From a33f660026a08bed477bce550a9777a21f6d5159 Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Thu, 30 Mar 2017 22:33:12 -0400
Subject: [PATCH 01/32] Cherry-pick flash files from arty-soc branch. Add SPI
 flash bitbang test.

---
 firmware/Makefile |  1 +
 firmware/ci.c     |  8 ++++++++
 firmware/flash.c  | 31 +++++++++++++++++++++++++++++--
 firmware/flash.h  |  1 +
 4 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/firmware/Makefile b/firmware/Makefile
index 1076a6f8..91409c0d 100644
--- a/firmware/Makefile
+++ b/firmware/Makefile
@@ -24,6 +24,7 @@ OBJECTS=\
 	encoder.o \
 	etherbone.o \
 	ethernet.o \
+	flash.o \
 	fx2.o \
 	hdmi_in0.o \
 	hdmi_out0.o \
diff --git a/firmware/ci.c b/firmware/ci.c
index a8fdddb2..d02a14ed 100644
--- a/firmware/ci.c
+++ b/firmware/ci.c
@@ -31,6 +31,7 @@
 #include "config.h"
 #include "edid.h"
 #include "encoder.h"
+#include "flash.h"
 #include "fx2.h"
 #include "hdmi_in0.h"
 #include "hdmi_in1.h"
@@ -174,6 +175,9 @@ static void help_debug(void)
 #endif
 	wputs("  debug dna                      - show Board's DNA");
 	wputs("  debug edid                     - dump monitor EDID");
+#ifdef CSR_SPIFLASH_BASE
+	wputs("  debug spiflash                 - test bitbang write");
+#endif
 #ifdef CSR_CAS_BASE
 	wputs("  debug cas leds <value>         - change the status LEDs");
 	wputs("  debug cas switches             - read the control switches status");
@@ -1266,6 +1270,10 @@ void ci_service(void)
 #endif
 			if(found == 0)
 				wprintf("%s port has no EDID capabilities\r\n", token);
+#ifdef CSR_SPIFLASH_BASE
+		} else if(strcmp(token, "spiflash") == 0) {
+				bitbang_test();
+#endif
 #ifdef CSR_CAS_BASE
 		} else if(strcmp(token, "cas") == 0) {
 			token = get_token(&str);
diff --git a/firmware/flash.c b/firmware/flash.c
index ed3e1c8d..d30c58f6 100644
--- a/firmware/flash.c
+++ b/firmware/flash.c
@@ -1,4 +1,5 @@
 #include <generated/csr.h>
+#include <generated/mem.h>
 #ifdef SPIFLASH_PAGE_SIZE
 #include "flash.h"
 
@@ -7,6 +8,7 @@
 #include <stdint.h>
 #include <time.h>
 #include <console.h>
+#include <spiflash.h>
 #include "ci.h"
 
 
@@ -53,7 +55,7 @@ static void dump_bytes(unsigned int *ptr, int count, unsigned addr)
 
 static void mr(unsigned int addr, unsigned int length)
 {
-	dump_bytes(addr, length, (unsigned)addr);
+	dump_bytes((unsigned int *) addr, length, (unsigned)addr);
 }
 
 void flash_test(void) {
@@ -61,4 +63,29 @@ void flash_test(void) {
 	mr(0x20000000, test_size);
 }
 
-#endif
\ No newline at end of file
+void bitbang_test(void) {
+	unsigned int *flashbase;
+	unsigned int length;
+	unsigned int *free_start;
+	unsigned int free_space;
+	int i = 0;
+
+	unsigned int buf[512];
+
+	flashbase = (unsigned int *)FLASH_BOOT_ADDRESS;
+	length = *flashbase++;
+	free_start = flashbase + length;
+	free_space = (unsigned int *)(SPIFLASH_BASE + SPIFLASH_SIZE) - free_start;
+
+	printf("Free space begins at %X, size %d bytes.\n", free_start, free_space);
+	mr((unsigned int) free_start, 512);
+
+	for(i = 0; i < 512; i++) {
+		buf[i] = ~(*(free_start + i));
+	}
+
+	write_to_flash((unsigned int) free_start, (unsigned char *) buf, 512);
+	mr((unsigned int) free_start, 512);
+}
+
+#endif
diff --git a/firmware/flash.h b/firmware/flash.h
index 8e09be7a..7e1b4b31 100644
--- a/firmware/flash.h
+++ b/firmware/flash.h
@@ -2,5 +2,6 @@
 #define __FLASH_H
 
 void flash_test(void);
+void bitbang_test(void);
 
 #endif /* __FLASH_H */

From afb11eff9351b063673479665fd576a84918f907 Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Thu, 30 Mar 2017 21:57:33 -0400
Subject: [PATCH 02/32] Add erase free area to bitbang test.

---
 firmware/flash.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/firmware/flash.c b/firmware/flash.c
index d30c58f6..ce3b1b42 100644
--- a/firmware/flash.c
+++ b/firmware/flash.c
@@ -86,6 +86,7 @@ void bitbang_test(void) {
 
 	write_to_flash((unsigned int) free_start, (unsigned char *) buf, 512);
 	mr((unsigned int) free_start, 512);
+	erase_flash_sector((unsigned int) free_start);
 }
 
 #endif

From 0662522489d92822e292a608f09038e53fda2cfc Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Thu, 30 Mar 2017 21:58:09 -0400
Subject: [PATCH 03/32] Flush data cache between reads in bitbang test.

---
 firmware/flash.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/firmware/flash.c b/firmware/flash.c
index ce3b1b42..a59b1bc1 100644
--- a/firmware/flash.c
+++ b/firmware/flash.c
@@ -9,6 +9,7 @@
 #include <time.h>
 #include <console.h>
 #include <spiflash.h>
+#include <system.h>
 #include "ci.h"
 
 
@@ -85,6 +86,7 @@ void bitbang_test(void) {
 	}
 
 	write_to_flash((unsigned int) free_start, (unsigned char *) buf, 512);
+	flush_cpu_dcache();
 	mr((unsigned int) free_start, 512);
 	erase_flash_sector((unsigned int) free_start);
 }

From 13e75f1cd5f1d281ab8f8bf4b21cfb98de85ac6c Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Sun, 2 Apr 2017 00:07:02 -0400
Subject: [PATCH 04/32] Add non-zero write to spiflash debug.

---
 firmware/flash.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/firmware/flash.c b/firmware/flash.c
index a59b1bc1..3f542fae 100644
--- a/firmware/flash.c
+++ b/firmware/flash.c
@@ -82,7 +82,7 @@ void bitbang_test(void) {
 	mr((unsigned int) free_start, 512);
 
 	for(i = 0; i < 512; i++) {
-		buf[i] = ~(*(free_start + i));
+		buf[i] = (unsigned int) i;
 	}
 
 	write_to_flash((unsigned int) free_start, (unsigned char *) buf, 512);

From f435a0dc956e38a2adaf67a4e80a255e46e021eb Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Sun, 2 Apr 2017 01:50:38 -0400
Subject: [PATCH 05/32] Fix include guard for flash bitbang interface.

---
 firmware/flash.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/firmware/flash.c b/firmware/flash.c
index 3f542fae..5453ce24 100644
--- a/firmware/flash.c
+++ b/firmware/flash.c
@@ -1,6 +1,6 @@
 #include <generated/csr.h>
 #include <generated/mem.h>
-#ifdef SPIFLASH_PAGE_SIZE
+#if (defined CSR_SPIFLASH_BASE && defined SPIFLASH_PAGE_SIZE)
 #include "flash.h"
 
 #include <stdio.h>

From 0cfbf8517cf44546e4298cb13901df0faa990b79 Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thorr0505@comcast.net>
Date: Fri, 4 Aug 2017 18:48:36 -0400
Subject: [PATCH 06/32] Add stub xmodem/sfl implementation.

---
 firmware/ci.c    | 86 +++++++++++++++++++++++++++++++++++++++++++++++-
 firmware/flash.c | 40 +++++++++++++++++++---
 firmware/flash.h |  5 +++
 3 files changed, 126 insertions(+), 5 deletions(-)

diff --git a/firmware/ci.c b/firmware/ci.c
index d02a14ed..17294e51 100644
--- a/firmware/ci.c
+++ b/firmware/ci.c
@@ -186,6 +186,15 @@ static void help_debug(void)
 #endif
 }
 
+static void help_write(void)
+{
+	wputs("write commands");
+#ifdef CSR_SPIFLASH_BASE
+	wputs("  write spi xmodem addr len      - upload new spi flash firmware (xmodem)");
+	wputs("  write spi sfl addr len crc     - upload new spi flash firmware (flterm)");
+#endif
+}
+
 static void ci_help(void)
 {
 	wputs("help        - this command");
@@ -227,6 +236,7 @@ static void ci_help(void)
 	wputs("");
 #endif
 	help_debug();
+	help_write();
 }
 
 static char *readstr(void)
@@ -974,6 +984,68 @@ static void debug_ddr(void)
 }
 #endif
 
+#undef NEXT_TOKEN_OR_RETURN
+#define NEXT_TOKEN_OR_RETURN(s, t, reason)				\
+	if(!(t = get_token(&s))) {				\
+		wprintf("Parse failed - " reason " \r\n");	\
+		return;						\
+	}
+
+#ifdef CSR_SPIFLASH_BASE
+static void write_spi(char* str)
+{
+	char *token;
+	int rc;
+	unsigned long addr;
+	unsigned long len;
+	unsigned long crc;
+
+
+	token = get_token(&str);
+
+	if(strcmp(token, "xmodem") == 0) {
+		NEXT_TOKEN_OR_RETURN(str, token, "Invalid address.");
+		addr = atoi(token);
+
+		NEXT_TOKEN_OR_RETURN(str, token, "Invalid length.");
+		len = atoi(token);
+
+		// Get CRC anyway to consume the entire line just in case, but ignore it.
+		get_token(&str);
+		(void) crc;
+
+		wprintf("Will use xmodem with addr %lX, len %ld.\r\n", addr, len);
+		rc = write_xmodem(addr, len);
+	}
+	else if(strcmp(token, "sfl") == 0) {
+		NEXT_TOKEN_OR_RETURN(str, token, "Invalid address.");
+		addr = atoi(token);
+
+		NEXT_TOKEN_OR_RETURN(str, token, "Invalid length.");
+		len = atoi(token);
+
+		NEXT_TOKEN_OR_RETURN(str, token, "Invalid CRC.");
+		crc = atoi(token);
+
+		wprintf("Will use sfl with addr %lX, len %ld, and crc %lX.\r\n", addr, len, crc);
+		rc = write_sfl(addr, len, crc);
+	}
+	else {
+		wprintf("Protocol not supported.\r\n");
+		return;
+	}
+
+	if(rc == 0)
+		wprintf("New firmware written successfully.\r\n");
+	else if(rc == -1)
+		wprintf("CRC error transmitting firmware.\r\n");
+	else if(rc == -2)
+		wprintf("Flash comparison with in-memory image failed.\r\n");
+
+	return;
+}
+#endif
+
 void ci_prompt(void)
 {
 	wprintf("H2U %s>", uptime_str());
@@ -1022,6 +1094,8 @@ void ci_service(void)
 #endif
 		else if(strcmp(token, "debug") == 0)
 			help_debug();
+		else if(strcmp(token, "write") == 0)
+			help_write();
 		else
 			ci_help();
 		wputs("");
@@ -1303,7 +1377,17 @@ void ci_service(void)
 #endif
 		} else
 			help_debug();
-
+	} else if(strcmp(token, "write") == 0) {
+		token = get_token(&str);
+		if(false) { } // XXX: Replace with "command not supported?" if
+		// CSR_SPIFLASH_BASE isn't defined?
+#ifdef CSR_SPIFLASH_BASE
+		else if((strcmp(token, "spi") == 0) ) {
+			write_spi(str);
+		}
+#endif
+		else
+			help_write();
 	} else if(strcmp(token, "version") == 0) {
 		print_version();
 	} else {
diff --git a/firmware/flash.c b/firmware/flash.c
index 5453ce24..98fbd007 100644
--- a/firmware/flash.c
+++ b/firmware/flash.c
@@ -6,15 +6,18 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdint.h>
+#include <uart.h>
 #include <time.h>
 #include <console.h>
 #include <spiflash.h>
 #include <system.h>
 #include "ci.h"
 
-
 #define test_size 1024
 
+static char bitbang_buffer[128*1024];
+static char bus_buffer[128*1024];
+static char xmodem_buffer[1027];
 
 #define NUMBER_OF_BYTES_ON_A_LINE 16
 static void dump_bytes(unsigned int *ptr, int count, unsigned addr)
@@ -71,7 +74,8 @@ void bitbang_test(void) {
 	unsigned int free_space;
 	int i = 0;
 
-	unsigned int buf[512];
+	unsigned int buf_w[512];
+	unsigned int buf_r[512];
 
 	flashbase = (unsigned int *)FLASH_BOOT_ADDRESS;
 	length = *flashbase++;
@@ -82,13 +86,41 @@ void bitbang_test(void) {
 	mr((unsigned int) free_start, 512);
 
 	for(i = 0; i < 512; i++) {
-		buf[i] = (unsigned int) i;
+		buf_w[i] = (unsigned int) ( (i << 8) | i );
 	}
 
-	write_to_flash((unsigned int) free_start, (unsigned char *) buf, 512);
+	printf("Read using memory bus 1.\n");
+	write_to_flash((unsigned int) free_start, (unsigned char *) buf_w, 512);
 	flush_cpu_dcache();
 	mr((unsigned int) free_start, 512);
+
+	printf("Read using bitbang test.\n");
+	read_from_flash((unsigned int) free_start, (unsigned char *) buf_r, 512);
+	mr((unsigned int) &buf_r[0], 512); // &buf_r[0]: Collapse to ptr to first element.
+
+	printf("Read using memory bus 2.\n");
+	flush_cpu_dcache();
+	mr((unsigned int) free_start, 512);
+
 	erase_flash_sector((unsigned int) free_start);
 }
 
+
+#define SOH 1
+#define STX 2
+#define EOT 4
+#define ACK 6
+#define NAK 21
+#define CAN 24
+
+// Abbreviated xmodem.
+int write_xmodem(unsigned long addr, unsigned long len) {
+	return 0;
+}
+
+
+int write_sfl(unsigned long addr, unsigned long len, unsigned long crc) {
+	return 0;
+}
+
 #endif
diff --git a/firmware/flash.h b/firmware/flash.h
index 7e1b4b31..60838e4f 100644
--- a/firmware/flash.h
+++ b/firmware/flash.h
@@ -4,4 +4,9 @@
 void flash_test(void);
 void bitbang_test(void);
 
+#ifdef CSR_UART_BASE
+int write_xmodem(unsigned long addr, unsigned long len);
+int write_sfl(unsigned long addr, unsigned long len, unsigned long crc);
+#endif
+
 #endif /* __FLASH_H */

From 72a4bce82fd6bba71a7ecf602a2c9f6ac0c80e6b Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thorr0505@comcast.net>
Date: Fri, 4 Aug 2017 23:51:01 -0400
Subject: [PATCH 07/32] Add XMODEM implementation for SPI (currently
 nonfunctional).

---
 firmware/flash.c | 303 ++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 302 insertions(+), 1 deletion(-)

diff --git a/firmware/flash.c b/firmware/flash.c
index 98fbd007..ae8ee68f 100644
--- a/firmware/flash.c
+++ b/firmware/flash.c
@@ -4,8 +4,10 @@
 #include "flash.h"
 
 #include <stdio.h>
+#include <limits.h>
 #include <stdlib.h>
 #include <stdint.h>
+#include <string.h>
 #include <uart.h>
 #include <time.h>
 #include <console.h>
@@ -17,7 +19,7 @@
 
 static char bitbang_buffer[128*1024];
 static char bus_buffer[128*1024];
-static char xmodem_buffer[1027];
+static char xmodem_buffer[1029];
 
 #define NUMBER_OF_BYTES_ON_A_LINE 16
 static void dump_bytes(unsigned int *ptr, int count, unsigned addr)
@@ -106,6 +108,16 @@ void bitbang_test(void) {
 }
 
 
+// XMODEM:
+// 10 tries to receive first char of packet- 10 seconds each
+// First char of first packet special- either send NAK or C (for CRC)
+
+
+// 1 second timeout for each recv'd char otherwise.
+
+// XMODEM helpers
+
+
 #define SOH 1
 #define STX 2
 #define EOT 4
@@ -113,12 +125,301 @@ void bitbang_test(void) {
 #define NAK 21
 #define CAN 24
 
+static inline unsigned short generate_crc(char * data, size_t size)
+{
+	const unsigned int crc_poly = 0x1021;
+	unsigned int crc = 0x0000;
+
+	for(unsigned int octet_count = 0; octet_count < size; octet_count++)
+	{
+		crc = (crc ^ (unsigned int) (data[octet_count] & (0xFF)) << 8);
+		for(unsigned int bit_count = 1; bit_count <= 8; bit_count++)
+		{
+			if(crc & 0x8000)
+			{
+				crc = (crc << 1) ^ crc_poly;
+			}
+			else
+			{
+				crc <<= 1;
+			}       
+		}
+	}
+	return crc;
+}
+
+
+// Return:
+// 0- Read was okay.
+// 1- We timed out.
+static int recv_with_timeout(unsigned int timeout, char * recvd) {
+	// Software-based timeout for now while QEMU timer is broken.
+	// 1/100th of clock frequency worked well for me.
+	for(unsigned int i = 0; i < CONFIG_CLOCK_FREQUENCY/100; i++) {
+		for(unsigned int j = 0; j < timeout; j++) {
+			//printf("%d, %d", i, j);
+			if(uart_read_nonblock()) {
+				*recvd = uart_read();
+				return 0;
+			}	
+		}
+	}
+	
+	return -1;
+}
+
+
+// Clear UART buffer until timeout occurs.
+static void purge_uart_buffer(void) {
+	char dummy;
+	while(recv_with_timeout(1, &dummy) == 0);
+}
+
+
+// Return
+// 0- Recv okay
+// -1- Transmitter timed out
+// -2- Using 1k and checksum- This doesn't make sense.
+// Full packet (including already filled start char) should be
+// passed into this function.
+static int recv_packet_with_timeout(char * packet, int using_crc, int using_1k) {
+	int bytes_total = 3; // 2 bytes for block number and ones-compl
+	
+	if(using_crc) {
+		bytes_total += 2;
+	} else {
+		bytes_total += 1;
+	} 
+	
+	if(using_1k) {
+		if(using_crc) {
+			return -2;
+		} else {
+			bytes_total += 1024;
+		}
+	} else {
+		bytes_total += 128;
+	}
+
+	for(int i = 1; i < bytes_total; i++) {
+		char xmit;
+		
+		if(recv_with_timeout(1, &xmit) == -1) {
+			return -1;
+		} else {
+			packet[i] = xmit;	
+		}
+	}
+	
+	return 0;
+}
+
+// Return codes:
+// 128 or 1024
+// -1- Invalid config
+static inline int payload_len(int using_crc, int using_1k) {
+	if(using_1k) {
+		if(using_crc) {
+			return -1;
+		} else {
+			return 1024;
+		}
+	} else {
+		return 128;
+	}
+}
+
+
+// Return codes:
+// 1- Previous block was resent- everything else okay.
+// 0- All is okay
+// -1- Invalid configuration
+// -2- Block mismatch in header
+// -3- Unexpected block
+// -4- Bad CRC/Checksum
+static inline int verify_packet(char * packet, unsigned char expected_block, int using_crc, int using_1k) {
+	int rc = 0;
+	
+	if(packet[1] == (expected_block - 1)) {
+		rc = 1;
+	} else if(packet[1] == expected_block) {
+		rc = 0; // Do nothing
+	} else {
+		return -3;
+	}
+
+	if(!(packet[1] == !packet[2])) {
+		return -2;
+	}
+
+	if(using_crc) {
+		if(!(generate_crc(&packet[3], payload_len(using_crc, using_1k) == 0))) {
+			return -4;
+		}
+	} else {
+		return -4; // Not implemented yet
+	}
+	
+	return rc;
+}
+
+
 // Abbreviated xmodem.
 int write_xmodem(unsigned long addr, unsigned long len) {
+	int using_1k = 0;
+	int using_crc = 1;
+	int initial_retries = 0;
+	unsigned int data_offset = 0;
+	unsigned char expected_block = 1;
+	
+	// Initial handshake
+	for(initial_retries = 0; initial_retries < 10; initial_retries++) {
+		char first;
+		char send = using_crc ? 'C' : NAK;
+		uart_write(send);
+		int res = recv_with_timeout(10, &first);
+
+		if(res == 0) {
+			switch(first) {
+				case SOH:
+					xmodem_buffer[0] = first;
+					goto initial_handshake_over;
+					break;
+				case STX:
+					xmodem_buffer[0] = first;
+					using_1k = 1;
+					goto initial_handshake_over;
+					break;
+				default:
+					// Unexpected/invalid char.
+					purge_uart_buffer();
+					break;
+			}
+		}
+		
+		// Switch to checksum mode after three timeouts.
+		if(initial_retries == 3) {
+			using_crc = 0; // Only set here. 
+		}
+	}
+	
+initial_handshake_over:
+	if(initial_retries >= 10) {
+		return -1;
+	}
+	
+	int initial_handshake_occurred = 1;
+	int done = 0;
+	int num_errors = 0;
+	char send_code;
+	while(!done) {
+		// Skip this the first time around. For control flow purposes
+		// It makes sense to keep it at top of while loop.	
+		if(!initial_handshake_occurred) {
+			int res;
+			char first;
+			
+			if(num_errors >= 10) {
+				send_code = CAN;
+			}
+			
+			// Subsequent handshakes
+			if(send_code == NAK)
+			{
+				purge_uart_buffer();
+			}
+
+			uart_write(send_code);
+			if(send_code == CAN) {
+				return -1;
+			} else {
+				res = recv_with_timeout(10, &first);
+			}
+
+			if(res == 0) {
+				switch(first) {
+					case SOH:
+						xmodem_buffer[0] = first;
+						break;
+					case STX:
+						xmodem_buffer[0] = first;
+						using_1k = 1;
+						break;
+					case EOT:
+						done = 1;
+						continue;
+					default:
+						// Unexpected/invalid char.
+						send_code = NAK;
+						num_errors++;
+						continue;
+				}
+			} else {
+				send_code = NAK;
+				num_errors++;
+				continue;
+			}
+		}
+		
+		if(initial_handshake_occurred) {
+			initial_handshake_occurred = 0;
+		}
+		
+		
+		// Subsequent receives
+		int recv_rc = recv_packet_with_timeout(xmodem_buffer, using_crc, using_1k);
+		switch(recv_rc) {
+			case 0:
+				break;
+			case -2:
+				send_code = CAN;
+				num_errors++;
+				continue;
+			case -1:
+			default:
+				send_code = NAK;
+				num_errors++;
+				continue;
+		}
+		
+		int ver_rc = verify_packet(xmodem_buffer, expected_block, using_crc, using_1k);
+		switch(ver_rc) {
+			case 0:
+				// Assuming !using_crc && using_1k is impossible.
+				{
+					int len = payload_len(using_crc, using_1k);
+					memcpy(bus_buffer + data_offset + len, xmodem_buffer + 3, len);
+					data_offset += len;
+				}
+				send_code = ACK;
+				expected_block++;
+				break;
+			case 1: // Last block was resent. Nothing to do.
+				send_code = ACK;
+				break;
+			case -1:
+			case -3:
+				send_code = CAN;
+				num_errors++;
+				continue;
+			case -2:
+			case -4:
+			default:
+				send_code = NAK;
+				num_errors++;
+				continue;
+		}
+		
+		// Every time we successfully send a packet, reset error count.
+		num_errors = 0;
+	}
+	
 	return 0;
 }
 
 
+
+
 int write_sfl(unsigned long addr, unsigned long len, unsigned long crc) {
 	return 0;
 }

From 8ca8ed805a8051e9d7802df8c6d7cf5860f0b77c Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Fri, 18 Aug 2017 14:37:23 -0400
Subject: [PATCH 08/32] Integrate libmodem as submodule (library link
 compiles).

---
 .gitmodules          |  3 +++
 Makefile             |  8 +++++++-
 firmware/Makefile    | 15 ++++++++++++---
 third_party/libmodem |  1 +
 4 files changed, 23 insertions(+), 4 deletions(-)
 create mode 160000 third_party/libmodem

diff --git a/.gitmodules b/.gitmodules
index f2a04704..856c0dc9 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -28,3 +28,6 @@
 [submodule "third_party/flash_proxies"]
        path = third_party/flash_proxies
        url = https://github.com/jordens/bscan_spi_bitstreams
+[submodule "third_party/libmodem"]
+	path = third_party/libmodem
+	url = https://github.com/cr1901/libmodem
diff --git a/Makefile b/Makefile
index 8c937e05..c11664db 100644
--- a/Makefile
+++ b/Makefile
@@ -163,7 +163,11 @@ gateware-clean:
 
 # Firmware - the stuff which runs in the soft CPU inside the FPGA.
 # --------------------------------------
-firmware-cmd:
+FIRMWARE_MODULES=libmodem
+firmware-submodules: $(addsuffix /.git,$(addprefix third_party/,$(FIRMWARE_MODULES)))
+	@true
+
+firmware-cmd: firmware-submodules
 	mkdir -p $(TARGET_BUILD_DIR)
 ifneq ($(OS),Windows_NT)
 	$(MAKE_CMD) --no-compile-gateware \
@@ -199,6 +203,7 @@ firmware-clear: firmware-clear-$(PLATFORM)
 .PHONY: firmware-load-$(PLATFORM) firmware-flash-$(PLATFORM) firmware-connect-$(PLATFORM) firmware-clear-$(PLATFORM)
 
 firmware-clean:
+	cd third_party/libmodem && scons TARGET_OS=hdmi2usb-lm32 HDMI2USB_BUILD=$(PWD)/$(TARGET_BUILD_DIR) -c
 	rm -rf $(TARGET_BUILD_DIR)/software
 
 .PHONY: firmware-cmd $(FIRMWARE_FILEBASE).bin firmware firmware-load firmware-flash firmware-connect firmware-clean
@@ -353,6 +358,7 @@ reset: reset-$(PLATFORM)
 
 clean:
 	rm build/cache.mk
+	cd third_party/libmodem && scons TARGET_OS=hdmi2usb-lm32 HDMI2USB_BUILD=$(PWD)/$(TARGET_BUILD_DIR) -c
 	rm -rf $(TARGET_BUILD_DIR)
 	py3clean . || rm -rf $$(find -name __pycache__)
 
diff --git a/firmware/Makefile b/firmware/Makefile
index 91409c0d..fe46c3c5 100644
--- a/firmware/Makefile
+++ b/firmware/Makefile
@@ -16,6 +16,9 @@ CFLAGS += -DPLATFORM_$(UPLATFORM) -DTARGET_$(UTARGET)
 BUILD_DIRECTORY=$(BUILDINC_DIRECTORY)/../../
 FIRMBUILD_DIRECTORY=$(BUILD_DIRECTORY)/software/firmware
 
+LIBMODEM_DIR=../../../../third_party/libmodem
+LIBMODEM=$(LIBMODEM_DIR)/build/hdmi2usb-lm32/libmodem.a
+
 OBJECTS=\
 	bist.o \
 	ci.o \
@@ -53,7 +56,8 @@ OBJECTS=\
 
 CFLAGS += \
 	-I$(FIRMWARE_DIRECTORY) \
-	-I$(BUILD_DIRECTORY)/software/firmware
+	-I$(BUILD_DIRECTORY)/software/firmware \
+	-I$(LIBMODEM_DIR)/src
 
 CFLAGS += \
 	-Wall \
@@ -75,7 +79,7 @@ all: firmware.bin firmware.fbi
 	$(OBJCOPY) -O binary $< $@
 	chmod -x $@
 
-firmware.elf: $(FIRMWARE_DIRECTORY)/linker.ld $(OBJECTS)
+firmware.elf: $(FIRMWARE_DIRECTORY)/linker.ld $(OBJECTS) $(LIBMODEM)
 
 %.elf: ../libbase/crt0-$(CPU).o ../libbase/libbase-nofloat.a ../libcompiler_rt/libcompiler_rt.a ../uip/libuip.a
 	$(LD) $(LDFLAGS) \
@@ -88,7 +92,9 @@ firmware.elf: $(FIRMWARE_DIRECTORY)/linker.ld $(OBJECTS)
                 -L../libcompiler_rt \
 		-lcompiler_rt \
 		-L../uip \
-		-luip
+		-luip \
+		-L$(LIBMODEM_DIR)/build/hdmi2usb-lm32 \
+		-lmodem
 	chmod -x $@
 
 # pull in dependency info for *existing* .o files
@@ -133,4 +139,7 @@ $(FIRMBUILD_DIRECTORY)/hdmi_in1.c: $(FIRMWARE_DIRECTORY)/hdmi_in0.c $(FIRMWARE_D
 	# Check the files exist
 	[ -e $(FIRMBUILD_DIRECTORY)/hdmi_in1.c ]
 
+$(LIBMODEM):
+	cd $(LIBMODEM_DIR) && scons TARGET_OS=hdmi2usb-lm32 BUILD_TYPE=Release HDMI2USB_BUILD=$(BUILD_DIRECTORY)
+
 .PHONY: all clean libs version_data
diff --git a/third_party/libmodem b/third_party/libmodem
new file mode 160000
index 00000000..e3603ead
--- /dev/null
+++ b/third_party/libmodem
@@ -0,0 +1 @@
+Subproject commit e3603ead3525d70a316c7d6add50542a42a54d6d

From 9d90b0fb3b706c1bba8e78f12064c60f7cd829a2 Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Fri, 18 Aug 2017 23:35:18 -0400
Subject: [PATCH 09/32] Ensure rebuild of libmodem if contents change.

---
 firmware/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/firmware/Makefile b/firmware/Makefile
index fe46c3c5..95ff5543 100644
--- a/firmware/Makefile
+++ b/firmware/Makefile
@@ -139,7 +139,7 @@ $(FIRMBUILD_DIRECTORY)/hdmi_in1.c: $(FIRMWARE_DIRECTORY)/hdmi_in0.c $(FIRMWARE_D
 	# Check the files exist
 	[ -e $(FIRMBUILD_DIRECTORY)/hdmi_in1.c ]
 
-$(LIBMODEM):
+$(LIBMODEM): $(LIBMODEM_DIR)/src/*.c
 	cd $(LIBMODEM_DIR) && scons TARGET_OS=hdmi2usb-lm32 BUILD_TYPE=Release HDMI2USB_BUILD=$(BUILD_DIRECTORY)
 
 .PHONY: all clean libs version_data

From 36baad5404bedbd9dc6f41d7e225d365cd1da017 Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Fri, 18 Aug 2017 23:35:35 -0400
Subject: [PATCH 10/32] Start integrating libmodem into firmware.

---
 firmware/flash.c | 325 +++++------------------------------------------
 1 file changed, 35 insertions(+), 290 deletions(-)

diff --git a/firmware/flash.c b/firmware/flash.c
index ae8ee68f..f73e68ff 100644
--- a/firmware/flash.c
+++ b/firmware/flash.c
@@ -15,11 +15,23 @@
 #include <system.h>
 #include "ci.h"
 
+#include <modem.h>
+#include <serial.h>
+
 #define test_size 1024
 
-static char bitbang_buffer[128*1024];
-static char bus_buffer[128*1024];
-static char xmodem_buffer[1029];
+static unsigned char __attribute__ ((section ("main_ram"))) bitbang_buffer[128*1024];
+static unsigned char __attribute__ ((section ("main_ram"))) bus_buffer[128*1024];
+static unsigned char xmodem_buffer[1029];
+
+typedef struct flash_writer {
+	unsigned char * buf;
+	size_t inlen;
+	size_t bufpos;
+	size_t buflen;
+} flash_writer_t;
+
+int write_to_buf(const char * buf, const int buf_size, const int eof, void * const chan_state);
 
 #define NUMBER_OF_BYTES_ON_A_LINE 16
 static void dump_bytes(unsigned int *ptr, int count, unsigned addr)
@@ -118,310 +130,43 @@ void bitbang_test(void) {
 // XMODEM helpers
 
 
-#define SOH 1
-#define STX 2
-#define EOT 4
-#define ACK 6
-#define NAK 21
-#define CAN 24
+int write_to_buf(const char * buf, const int buf_size, const int eof, void * const chan_state) {
+	flash_writer_t * writer = chan_state;
 
-static inline unsigned short generate_crc(char * data, size_t size)
-{
-	const unsigned int crc_poly = 0x1021;
-	unsigned int crc = 0x0000;
-
-	for(unsigned int octet_count = 0; octet_count < size; octet_count++)
-	{
-		crc = (crc ^ (unsigned int) (data[octet_count] & (0xFF)) << 8);
-		for(unsigned int bit_count = 1; bit_count <= 8; bit_count++)
-		{
-			if(crc & 0x8000)
-			{
-				crc = (crc << 1) ^ crc_poly;
-			}
-			else
-			{
-				crc <<= 1;
-			}       
-		}
-	}
-	return crc;
-}
+	int space_left = writer->buflen - writer->bufpos;
 
+	int size_sent = space_left < buf_size ? space_left : buf_size;
+	memcpy(writer->buf, buf, size_sent);
 
-// Return:
-// 0- Read was okay.
-// 1- We timed out.
-static int recv_with_timeout(unsigned int timeout, char * recvd) {
-	// Software-based timeout for now while QEMU timer is broken.
-	// 1/100th of clock frequency worked well for me.
-	for(unsigned int i = 0; i < CONFIG_CLOCK_FREQUENCY/100; i++) {
-		for(unsigned int j = 0; j < timeout; j++) {
-			//printf("%d, %d", i, j);
-			if(uart_read_nonblock()) {
-				*recvd = uart_read();
-				return 0;
-			}	
-		}
-	}
-	
-	return -1;
+	writer->bufpos += size_sent;
+	return size_sent;
 }
 
+int write_xmodem(unsigned long addr, unsigned long len) {
+	flash_writer_t writer = { bitbang_buffer, len, 0, sizeof(bitbang_buffer)/sizeof(bitbang_buffer[0]) };
+	serial_handle_t uart;
 
-// Clear UART buffer until timeout occurs.
-static void purge_uart_buffer(void) {
 	char dummy;
-	while(recv_with_timeout(1, &dummy) == 0);
-}
 
+	serial_init(0, 0, &uart);
+	serial_flush(uart);
+	int xrc = xmodem_rx(write_to_buf, xmodem_buffer, &writer, uart, XMODEM_1K);
 
-// Return
-// 0- Recv okay
-// -1- Transmitter timed out
-// -2- Using 1k and checksum- This doesn't make sense.
-// Full packet (including already filled start char) should be
-// passed into this function.
-static int recv_packet_with_timeout(char * packet, int using_crc, int using_1k) {
-	int bytes_total = 3; // 2 bytes for block number and ones-compl
-	
-	if(using_crc) {
-		bytes_total += 2;
-	} else {
-		bytes_total += 1;
-	} 
-	
-	if(using_1k) {
-		if(using_crc) {
-			return -2;
-		} else {
-			bytes_total += 1024;
-		}
-	} else {
-		bytes_total += 128;
-	}
+	/* char data[] = "C";
+	for(int count = 0; count < 10; count++)
+	{
+		serial_rcv(&dummy, 1, 1, NULL, uart);
+		serial_snd(data, 1, uart);
+	} */
 
-	for(int i = 1; i < bytes_total; i++) {
-		char xmit;
-		
-		if(recv_with_timeout(1, &xmit) == -1) {
-			return -1;
-		} else {
-			packet[i] = xmit;	
-		}
-	}
-	
 	return 0;
 }
 
-// Return codes:
-// 128 or 1024
-// -1- Invalid config
-static inline int payload_len(int using_crc, int using_1k) {
-	if(using_1k) {
-		if(using_crc) {
-			return -1;
-		} else {
-			return 1024;
-		}
-	} else {
-		return 128;
-	}
-}
-
-
-// Return codes:
-// 1- Previous block was resent- everything else okay.
-// 0- All is okay
-// -1- Invalid configuration
-// -2- Block mismatch in header
-// -3- Unexpected block
-// -4- Bad CRC/Checksum
-static inline int verify_packet(char * packet, unsigned char expected_block, int using_crc, int using_1k) {
-	int rc = 0;
-	
-	if(packet[1] == (expected_block - 1)) {
-		rc = 1;
-	} else if(packet[1] == expected_block) {
-		rc = 0; // Do nothing
-	} else {
-		return -3;
-	}
-
-	if(!(packet[1] == !packet[2])) {
-		return -2;
-	}
-
-	if(using_crc) {
-		if(!(generate_crc(&packet[3], payload_len(using_crc, using_1k) == 0))) {
-			return -4;
-		}
-	} else {
-		return -4; // Not implemented yet
-	}
-	
-	return rc;
-}
-
-
-// Abbreviated xmodem.
-int write_xmodem(unsigned long addr, unsigned long len) {
-	int using_1k = 0;
-	int using_crc = 1;
-	int initial_retries = 0;
-	unsigned int data_offset = 0;
-	unsigned char expected_block = 1;
-	
-	// Initial handshake
-	for(initial_retries = 0; initial_retries < 10; initial_retries++) {
-		char first;
-		char send = using_crc ? 'C' : NAK;
-		uart_write(send);
-		int res = recv_with_timeout(10, &first);
-
-		if(res == 0) {
-			switch(first) {
-				case SOH:
-					xmodem_buffer[0] = first;
-					goto initial_handshake_over;
-					break;
-				case STX:
-					xmodem_buffer[0] = first;
-					using_1k = 1;
-					goto initial_handshake_over;
-					break;
-				default:
-					// Unexpected/invalid char.
-					purge_uart_buffer();
-					break;
-			}
-		}
-		
-		// Switch to checksum mode after three timeouts.
-		if(initial_retries == 3) {
-			using_crc = 0; // Only set here. 
-		}
-	}
-	
-initial_handshake_over:
-	if(initial_retries >= 10) {
-		return -1;
-	}
-	
-	int initial_handshake_occurred = 1;
-	int done = 0;
-	int num_errors = 0;
-	char send_code;
-	while(!done) {
-		// Skip this the first time around. For control flow purposes
-		// It makes sense to keep it at top of while loop.	
-		if(!initial_handshake_occurred) {
-			int res;
-			char first;
-			
-			if(num_errors >= 10) {
-				send_code = CAN;
-			}
-			
-			// Subsequent handshakes
-			if(send_code == NAK)
-			{
-				purge_uart_buffer();
-			}
-
-			uart_write(send_code);
-			if(send_code == CAN) {
-				return -1;
-			} else {
-				res = recv_with_timeout(10, &first);
-			}
-
-			if(res == 0) {
-				switch(first) {
-					case SOH:
-						xmodem_buffer[0] = first;
-						break;
-					case STX:
-						xmodem_buffer[0] = first;
-						using_1k = 1;
-						break;
-					case EOT:
-						done = 1;
-						continue;
-					default:
-						// Unexpected/invalid char.
-						send_code = NAK;
-						num_errors++;
-						continue;
-				}
-			} else {
-				send_code = NAK;
-				num_errors++;
-				continue;
-			}
-		}
-		
-		if(initial_handshake_occurred) {
-			initial_handshake_occurred = 0;
-		}
-		
-		
-		// Subsequent receives
-		int recv_rc = recv_packet_with_timeout(xmodem_buffer, using_crc, using_1k);
-		switch(recv_rc) {
-			case 0:
-				break;
-			case -2:
-				send_code = CAN;
-				num_errors++;
-				continue;
-			case -1:
-			default:
-				send_code = NAK;
-				num_errors++;
-				continue;
-		}
-		
-		int ver_rc = verify_packet(xmodem_buffer, expected_block, using_crc, using_1k);
-		switch(ver_rc) {
-			case 0:
-				// Assuming !using_crc && using_1k is impossible.
-				{
-					int len = payload_len(using_crc, using_1k);
-					memcpy(bus_buffer + data_offset + len, xmodem_buffer + 3, len);
-					data_offset += len;
-				}
-				send_code = ACK;
-				expected_block++;
-				break;
-			case 1: // Last block was resent. Nothing to do.
-				send_code = ACK;
-				break;
-			case -1:
-			case -3:
-				send_code = CAN;
-				num_errors++;
-				continue;
-			case -2:
-			case -4:
-			default:
-				send_code = NAK;
-				num_errors++;
-				continue;
-		}
-		
-		// Every time we successfully send a packet, reset error count.
-		num_errors = 0;
-	}
-	
+int write_sfl(unsigned long addr, unsigned long len, unsigned long crc) {
 	return 0;
 }
 
 
 
 
-int write_sfl(unsigned long addr, unsigned long len, unsigned long crc) {
-	return 0;
-}
-
 #endif

From beb0f356a50c58813076ebcf1b9820e6d7fdaaff Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Sat, 19 Aug 2017 20:19:57 -0400
Subject: [PATCH 11/32] XMODEM xfers now succeed with libmodem. Update libmodem
 submodule.

---
 firmware/ci.c        |  2 ++
 firmware/flash.c     | 21 +++++++++++----------
 third_party/libmodem |  2 +-
 3 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/firmware/ci.c b/firmware/ci.c
index 17294e51..acffcaff 100644
--- a/firmware/ci.c
+++ b/firmware/ci.c
@@ -1041,6 +1041,8 @@ static void write_spi(char* str)
 		wprintf("CRC error transmitting firmware.\r\n");
 	else if(rc == -2)
 		wprintf("Flash comparison with in-memory image failed.\r\n");
+	else
+		wprintf("Unspecified error: %d\r\n", rc);
 
 	return;
 }
diff --git a/firmware/flash.c b/firmware/flash.c
index f73e68ff..eb19fa88 100644
--- a/firmware/flash.c
+++ b/firmware/flash.c
@@ -146,18 +146,19 @@ int write_xmodem(unsigned long addr, unsigned long len) {
 	flash_writer_t writer = { bitbang_buffer, len, 0, sizeof(bitbang_buffer)/sizeof(bitbang_buffer[0]) };
 	serial_handle_t uart;
 
-	char dummy;
+	//if(addr < FLASH_BOOT_ADDRESS || addr > )
 
 	serial_init(0, 0, &uart);
-	serial_flush(uart);
-	int xrc = xmodem_rx(write_to_buf, xmodem_buffer, &writer, uart, XMODEM_1K);
-
-	/* char data[] = "C";
-	for(int count = 0; count < 10; count++)
-	{
-		serial_rcv(&dummy, 1, 1, NULL, uart);
-		serial_snd(data, 1, uart);
-	} */
+	int rc = xmodem_rx(write_to_buf, xmodem_buffer, &writer, uart, XMODEM_1K);
+	serial_close(&uart);
+
+	if(rc != MODEM_NO_ERRORS) {
+		return -1;
+	}
+
+	memcpy(bus_buffer, (void *) FLASH_BOOT_ADDRESS, len);
+	mr((unsigned int) &bus_buffer[0], 512);
+	mr((unsigned int) &bitbang_buffer[0], 512);
 
 	return 0;
 }
diff --git a/third_party/libmodem b/third_party/libmodem
index e3603ead..316bb2e2 160000
--- a/third_party/libmodem
+++ b/third_party/libmodem
@@ -1 +1 @@
-Subproject commit e3603ead3525d70a316c7d6add50542a42a54d6d
+Subproject commit 316bb2e270b3e0b9f1bec6478a6c3a2d63d0d804

From 61c0b008f113cfb93d001f913cec049b0c400a68 Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Sat, 19 Aug 2017 20:36:19 -0400
Subject: [PATCH 12/32] CRC token required for all xfer modes; BIOS uses it.

---
 firmware/ci.c    | 7 +++----
 firmware/flash.c | 6 ++++--
 firmware/flash.h | 2 +-
 3 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/firmware/ci.c b/firmware/ci.c
index acffcaff..491def17 100644
--- a/firmware/ci.c
+++ b/firmware/ci.c
@@ -1010,12 +1010,11 @@ static void write_spi(char* str)
 		NEXT_TOKEN_OR_RETURN(str, token, "Invalid length.");
 		len = atoi(token);
 
-		// Get CRC anyway to consume the entire line just in case, but ignore it.
-		get_token(&str);
-		(void) crc;
+		NEXT_TOKEN_OR_RETURN(str, token, "Invalid CRC.");
+		crc = atoi(token);
 
 		wprintf("Will use xmodem with addr %lX, len %ld.\r\n", addr, len);
-		rc = write_xmodem(addr, len);
+		rc = write_xmodem(addr, len, crc);
 	}
 	else if(strcmp(token, "sfl") == 0) {
 		NEXT_TOKEN_OR_RETURN(str, token, "Invalid address.");
diff --git a/firmware/flash.c b/firmware/flash.c
index eb19fa88..fab1d4eb 100644
--- a/firmware/flash.c
+++ b/firmware/flash.c
@@ -142,10 +142,12 @@ int write_to_buf(const char * buf, const int buf_size, const int eof, void * con
 	return size_sent;
 }
 
-int write_xmodem(unsigned long addr, unsigned long len) {
-	flash_writer_t writer = { bitbang_buffer, len, 0, sizeof(bitbang_buffer)/sizeof(bitbang_buffer[0]) };
+int write_xmodem(unsigned long addr, unsigned long len, unsigned long crc) {
+	flash_writer_t writer = { bitbang_buffer + 8, len, 0, sizeof(bitbang_buffer)/sizeof(bitbang_buffer[0]) };
 	serial_handle_t uart;
 
+	memcpy((void *) bitbang_buffer + 0, &len, sizeof(unsigned int));
+	memcpy((void *) bitbang_buffer + 4, &crc, sizeof(unsigned int));
 	//if(addr < FLASH_BOOT_ADDRESS || addr > )
 
 	serial_init(0, 0, &uart);
diff --git a/firmware/flash.h b/firmware/flash.h
index 60838e4f..eb40131f 100644
--- a/firmware/flash.h
+++ b/firmware/flash.h
@@ -5,7 +5,7 @@ void flash_test(void);
 void bitbang_test(void);
 
 #ifdef CSR_UART_BASE
-int write_xmodem(unsigned long addr, unsigned long len);
+int write_xmodem(unsigned long addr, unsigned long len, unsigned long crc);
 int write_sfl(unsigned long addr, unsigned long len, unsigned long crc);
 #endif
 

From f6d4830a28d2a3206258263b7b39782d3648f22c Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Sat, 19 Aug 2017 22:20:02 -0400
Subject: [PATCH 13/32] Move .bss to main_ram so file buffers fit.

---
 firmware/flash.c   | 4 ++--
 firmware/linker.ld | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/firmware/flash.c b/firmware/flash.c
index fab1d4eb..b9b73a30 100644
--- a/firmware/flash.c
+++ b/firmware/flash.c
@@ -20,8 +20,8 @@
 
 #define test_size 1024
 
-static unsigned char __attribute__ ((section ("main_ram"))) bitbang_buffer[128*1024];
-static unsigned char __attribute__ ((section ("main_ram"))) bus_buffer[128*1024];
+static unsigned char bitbang_buffer[128*1024];
+static unsigned char bus_buffer[128*1024];
 static unsigned char xmodem_buffer[1029];
 
 typedef struct flash_writer {
diff --git a/firmware/linker.ld b/firmware/linker.ld
index 420a48d1..3cc8aff8 100644
--- a/firmware/linker.ld
+++ b/firmware/linker.ld
@@ -47,7 +47,7 @@ SECTIONS
 		. = ALIGN(4);
 		_ebss = .;
 		_end = .;
-	} > sram
+	} > main_ram
 }
 
 PROVIDE(_fstack = ORIGIN(sram) + LENGTH(sram) - 4);

From 3ccd4862504b50430e8f6be4357b50d69a4e0252 Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Sat, 19 Aug 2017 22:38:58 -0400
Subject: [PATCH 14/32] Allow hex values for write commands.

---
 firmware/ci.c    | 33 ++++++++++++++++++++++++++-------
 firmware/flash.c |  8 ++++++++
 2 files changed, 34 insertions(+), 7 deletions(-)

diff --git a/firmware/ci.c b/firmware/ci.c
index 491def17..f1400f38 100644
--- a/firmware/ci.c
+++ b/firmware/ci.c
@@ -996,6 +996,7 @@ static void write_spi(char* str)
 {
 	char *token;
 	int rc;
+	char * endptr;
 	unsigned long addr;
 	unsigned long len;
 	unsigned long crc;
@@ -1005,26 +1006,44 @@ static void write_spi(char* str)
 
 	if(strcmp(token, "xmodem") == 0) {
 		NEXT_TOKEN_OR_RETURN(str, token, "Invalid address.");
-		addr = atoi(token);
+		addr = strtoul(token, &endptr, 0);
+		if(*endptr != '\0') {
+			wprintf("Invalid chars in address.");
+		}
 
 		NEXT_TOKEN_OR_RETURN(str, token, "Invalid length.");
-		len = atoi(token);
+		len = strtoul(token, &endptr, 0);
+		if(*endptr != '\0') {
+			wprintf("Invalid chars in length.");
+		}
 
 		NEXT_TOKEN_OR_RETURN(str, token, "Invalid CRC.");
-		crc = atoi(token);
+		crc = strtoul(token, &endptr, 0);
+		if(*endptr != '\0') {
+			wprintf("Invalid chars in CRC.");
+		}
 
-		wprintf("Will use xmodem with addr %lX, len %ld.\r\n", addr, len);
+		wprintf("Will use xmodem with addr %lX, len %ld and crc %lX.\r\n", addr, len, crc);
 		rc = write_xmodem(addr, len, crc);
 	}
 	else if(strcmp(token, "sfl") == 0) {
 		NEXT_TOKEN_OR_RETURN(str, token, "Invalid address.");
-		addr = atoi(token);
+		addr = strtoul(token, &endptr, 0);
+		if(*endptr != '\0') {
+			wprintf("Invalid chars in address.");
+		}
 
 		NEXT_TOKEN_OR_RETURN(str, token, "Invalid length.");
-		len = atoi(token);
+		len = strtoul(token, &endptr, 0);
+		if(*endptr != '\0') {
+			wprintf("Invalid chars in length.");
+		}
 
 		NEXT_TOKEN_OR_RETURN(str, token, "Invalid CRC.");
-		crc = atoi(token);
+		crc = strtoul(token, &endptr, 0);
+		if(*endptr != '\0') {
+			wprintf("Invalid chars in CRC.");
+		}
 
 		wprintf("Will use sfl with addr %lX, len %ld, and crc %lX.\r\n", addr, len, crc);
 		rc = write_sfl(addr, len, crc);
diff --git a/firmware/flash.c b/firmware/flash.c
index b9b73a30..60909d59 100644
--- a/firmware/flash.c
+++ b/firmware/flash.c
@@ -159,6 +159,14 @@ int write_xmodem(unsigned long addr, unsigned long len, unsigned long crc) {
 	}
 
 	memcpy(bus_buffer, (void *) FLASH_BOOT_ADDRESS, len);
+
+	for(unsigned int count = 0; count < len; count++) {
+		if(bus_buffer[count] != bitbang_buffer[count]) {
+			wprintf("Comparison failed at offset %X\r\n", count)
+			return -2;
+		}
+	}
+
 	mr((unsigned int) &bus_buffer[0], 512);
 	mr((unsigned int) &bitbang_buffer[0], 512);
 

From 41d62786681e77d8a8db9ecacf67148a782b4a0a Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Sun, 20 Aug 2017 02:03:16 -0400
Subject: [PATCH 15/32] write_to_buf needs to move offset into buffer to avoid
 overwriting data.

---
 firmware/flash.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/firmware/flash.c b/firmware/flash.c
index 60909d59..66c1b250 100644
--- a/firmware/flash.c
+++ b/firmware/flash.c
@@ -136,7 +136,7 @@ int write_to_buf(const char * buf, const int buf_size, const int eof, void * con
 	int space_left = writer->buflen - writer->bufpos;
 
 	int size_sent = space_left < buf_size ? space_left : buf_size;
-	memcpy(writer->buf, buf, size_sent);
+	memcpy(writer->buf + writer->bufpos, buf, size_sent);
 
 	writer->bufpos += size_sent;
 	return size_sent;

From d99096eae2363cded6decfe5015a966701b345fc Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Sun, 20 Aug 2017 02:03:57 -0400
Subject: [PATCH 16/32] Do not write len/CRC; assume arbitrary data input.

---
 firmware/flash.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/firmware/flash.c b/firmware/flash.c
index 66c1b250..c6fd9b51 100644
--- a/firmware/flash.c
+++ b/firmware/flash.c
@@ -143,13 +143,9 @@ int write_to_buf(const char * buf, const int buf_size, const int eof, void * con
 }
 
 int write_xmodem(unsigned long addr, unsigned long len, unsigned long crc) {
-	flash_writer_t writer = { bitbang_buffer + 8, len, 0, sizeof(bitbang_buffer)/sizeof(bitbang_buffer[0]) };
+	flash_writer_t writer = { bitbang_buffer, len, 0, sizeof(bitbang_buffer)/sizeof(bitbang_buffer[0]) };
 	serial_handle_t uart;
 
-	memcpy((void *) bitbang_buffer + 0, &len, sizeof(unsigned int));
-	memcpy((void *) bitbang_buffer + 4, &crc, sizeof(unsigned int));
-	//if(addr < FLASH_BOOT_ADDRESS || addr > )
-
 	serial_init(0, 0, &uart);
 	int rc = xmodem_rx(write_to_buf, xmodem_buffer, &writer, uart, XMODEM_1K);
 	serial_close(&uart);

From ed8d2031f29631f21dc0787d8754dfe3dfd90b31 Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Sun, 20 Aug 2017 02:05:33 -0400
Subject: [PATCH 17/32] write_xmodem() at arbitrary flash addresses is
 functional.

---
 firmware/flash.c | 59 ++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 55 insertions(+), 4 deletions(-)

diff --git a/firmware/flash.c b/firmware/flash.c
index c6fd9b51..8a0e6a32 100644
--- a/firmware/flash.c
+++ b/firmware/flash.c
@@ -23,6 +23,8 @@
 static unsigned char bitbang_buffer[128*1024];
 static unsigned char bus_buffer[128*1024];
 static unsigned char xmodem_buffer[1029];
+static unsigned char sector_buf_pre[SPIFLASH_SECTOR_SIZE];
+static unsigned char sector_buf_post[SPIFLASH_SECTOR_SIZE];
 
 typedef struct flash_writer {
 	unsigned char * buf;
@@ -154,17 +156,66 @@ int write_xmodem(unsigned long addr, unsigned long len, unsigned long crc) {
 		return -1;
 	}
 
-	memcpy(bus_buffer, (void *) FLASH_BOOT_ADDRESS, len);
+	// Do CRC check. Return if no match.
+
+	printf("Phase 3: Erase flash region.\r\n");
+	/* All end ptrs are "one past the last byte used for data of the
+	previous start ptr". */
+	unsigned int erase_addr = addr;
+	unsigned int erase_end = erase_addr + len;
+	unsigned int sector_start = erase_addr & ~(SPIFLASH_SECTOR_SIZE - 1);
+	unsigned int sector_end = (erase_end & ~(SPIFLASH_SECTOR_SIZE - 1)) + SPIFLASH_SECTOR_SIZE;
+	unsigned int prepend_len = erase_addr - sector_start;
+	unsigned int append_len = sector_end - erase_end;
+
+	memcpy(sector_buf_pre, (void *) sector_start, prepend_len);
+	memcpy(sector_buf_post, (void *) erase_end, append_len);
+	erase_flash_sector(sector_start);
+	printf("Write leading data.\r\n");
+	write_to_flash(sector_start, sector_buf_pre, prepend_len);
+	flush_cpu_dcache();
+
+	unsigned int middle_sectors = sector_start + SPIFLASH_SECTOR_SIZE;
+
+	while(middle_sectors < sector_end) {
+		erase_flash_sector(middle_sectors);
+		middle_sectors += SPIFLASH_SECTOR_SIZE;
+	}
+
+	printf("Write trailing data.\r\n");
+	write_to_flash(erase_end, sector_buf_post, append_len);
+	flush_cpu_dcache();
+
+	printf("Phase 4: Writing new data to flash.\r\n");
+	write_to_flash(addr, (unsigned char *) bitbang_buffer, len);
+	flush_cpu_dcache();
 
+	memcpy(bus_buffer, (void *) addr, len);
+	printf("Phase 5: Comparing memory bus to received data.\r\n");
 	for(unsigned int count = 0; count < len; count++) {
 		if(bus_buffer[count] != bitbang_buffer[count]) {
-			wprintf("Comparison failed at offset %X\r\n", count)
+			printf("Comparison failed at offset %X\r\n", count);
+			mr((unsigned int) &bus_buffer[count], 512);
+			mr((unsigned int) &bitbang_buffer[count], 512);
 			return -2;
 		}
 	}
 
-	mr((unsigned int) &bus_buffer[0], 512);
-	mr((unsigned int) &bitbang_buffer[0], 512);
+	/* Phase 6 comparison. */
+	memset(bitbang_buffer, '\0', len);
+	printf("Phase 6: Comparing memory bus to bitbang reads.\r\n");
+	read_from_flash(addr, (unsigned char *) bitbang_buffer, len);
+	for(unsigned int count = 0; count < len; count++) {
+		if(bus_buffer[count] != bitbang_buffer[count]) {
+			printf("Comparison failed at offset %X\r\n", count);
+			mr((unsigned int) &bus_buffer[count], 512);
+			mr((unsigned int) &bitbang_buffer[count], 512);
+			return -2;
+		}
+	}
+
+	flush_cpu_dcache();
+	mr(addr, 512);
 
 	return 0;
 }

From 86a116a2d814773d6d99ae636d778fe1bfdccaa8 Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Sun, 20 Aug 2017 02:44:13 -0400
Subject: [PATCH 18/32] Mild refactor of SPI flash write code paths.

---
 firmware/ci.c    | 78 ++++++++++++++++++++++--------------------------
 firmware/flash.c | 67 ++++++++++++++++++++++-------------------
 2 files changed, 72 insertions(+), 73 deletions(-)

diff --git a/firmware/ci.c b/firmware/ci.c
index f1400f38..dce67aa9 100644
--- a/firmware/ci.c
+++ b/firmware/ci.c
@@ -995,64 +995,58 @@ static void debug_ddr(void)
 static void write_spi(char* str)
 {
 	char *token;
-	int rc;
+	int rc = 0;
 	char * endptr;
 	unsigned long addr;
 	unsigned long len;
 	unsigned long crc;
-
+	int use_xmodem = 0, use_sfl = 0;
+	char * proto_str;
 
 	token = get_token(&str);
 
 	if(strcmp(token, "xmodem") == 0) {
-		NEXT_TOKEN_OR_RETURN(str, token, "Invalid address.");
-		addr = strtoul(token, &endptr, 0);
-		if(*endptr != '\0') {
-			wprintf("Invalid chars in address.");
-		}
-
-		NEXT_TOKEN_OR_RETURN(str, token, "Invalid length.");
-		len = strtoul(token, &endptr, 0);
-		if(*endptr != '\0') {
-			wprintf("Invalid chars in length.");
-		}
-
-		NEXT_TOKEN_OR_RETURN(str, token, "Invalid CRC.");
-		crc = strtoul(token, &endptr, 0);
-		if(*endptr != '\0') {
-			wprintf("Invalid chars in CRC.");
-		}
-
-		wprintf("Will use xmodem with addr %lX, len %ld and crc %lX.\r\n", addr, len, crc);
-		rc = write_xmodem(addr, len, crc);
+		use_xmodem = 1;
+		proto_str = "xmodem";
 	}
 	else if(strcmp(token, "sfl") == 0) {
-		NEXT_TOKEN_OR_RETURN(str, token, "Invalid address.");
-		addr = strtoul(token, &endptr, 0);
-		if(*endptr != '\0') {
-			wprintf("Invalid chars in address.");
-		}
-
-		NEXT_TOKEN_OR_RETURN(str, token, "Invalid length.");
-		len = strtoul(token, &endptr, 0);
-		if(*endptr != '\0') {
-			wprintf("Invalid chars in length.");
-		}
-
-		NEXT_TOKEN_OR_RETURN(str, token, "Invalid CRC.");
-		crc = strtoul(token, &endptr, 0);
-		if(*endptr != '\0') {
-			wprintf("Invalid chars in CRC.");
-		}
-
-		wprintf("Will use sfl with addr %lX, len %ld, and crc %lX.\r\n", addr, len, crc);
-		rc = write_sfl(addr, len, crc);
+		use_sfl = 1;
+		proto_str = "sfl";
 	}
 	else {
 		wprintf("Protocol not supported.\r\n");
 		return;
 	}
 
+	NEXT_TOKEN_OR_RETURN(str, token, "Invalid address.");
+	addr = strtoul(token, &endptr, 0);
+	if(*endptr != '\0') {
+		wprintf("Invalid chars in address.");
+		return;
+	}
+
+	NEXT_TOKEN_OR_RETURN(str, token, "Invalid length.");
+	len = strtoul(token, &endptr, 0);
+	if(*endptr != '\0') {
+		wprintf("Invalid chars in length.");
+		return;
+	}
+
+	NEXT_TOKEN_OR_RETURN(str, token, "Invalid CRC.");
+	crc = strtoul(token, &endptr, 0);
+	if(*endptr != '\0') {
+		wprintf("Invalid chars in CRC.");
+		return;
+	}
+
+	wprintf("Will use %s with addr %lX, len %ld and crc %lX.\r\n", proto_str, addr, len, crc);
+	if(use_xmodem)
+		rc = write_xmodem(addr, len, crc);
+	else if(use_sfl)
+		rc = write_sfl(addr, len, crc);
+	else
+		rc = -3;
+
 	if(rc == 0)
 		wprintf("New firmware written successfully.\r\n");
 	else if(rc == -1)
diff --git a/firmware/flash.c b/firmware/flash.c
index 8a0e6a32..09feac19 100644
--- a/firmware/flash.c
+++ b/firmware/flash.c
@@ -34,6 +34,7 @@ typedef struct flash_writer {
 } flash_writer_t;
 
 int write_to_buf(const char * buf, const int buf_size, const int eof, void * const chan_state);
+static void write_to_flash_arb(unsigned int addr, unsigned int len, unsigned char * prepend_buf, unsigned char * append_buf);
 
 #define NUMBER_OF_BYTES_ON_A_LINE 16
 static void dump_bytes(unsigned int *ptr, int count, unsigned addr)
@@ -158,37 +159,7 @@ int write_xmodem(unsigned long addr, unsigned long len, unsigned long crc) {
 
 	// Do CRC check. Return if no match.
 
-	printf("Phase 3: Erase flash region.\r\n");
-	/* All end ptrs are "one past the last byte used for data of the
-	previous start ptr". */
-	unsigned int erase_addr = addr;
-	unsigned int erase_end = erase_addr + len;
-	unsigned int sector_start = erase_addr & ~(SPIFLASH_SECTOR_SIZE - 1);
-	unsigned int sector_end = (erase_end & ~(SPIFLASH_SECTOR_SIZE - 1)) + SPIFLASH_SECTOR_SIZE;
-	unsigned int prepend_len = erase_addr - sector_start;
-	unsigned int append_len = sector_end - erase_end;
-
-	memcpy(sector_buf_pre, (void *) sector_start, prepend_len);
-	memcpy(sector_buf_post, (void *) erase_end, append_len);
-	erase_flash_sector(sector_start);
-	printf("Write leading data.\r\n");
-	write_to_flash(sector_start, sector_buf_pre, prepend_len);
-	flush_cpu_dcache();
-
-	unsigned int middle_sectors = sector_start + SPIFLASH_SECTOR_SIZE;
-
-	while(middle_sectors < sector_end) {
-		erase_flash_sector(middle_sectors);
-		middle_sectors += SPIFLASH_SECTOR_SIZE;
-	}
-
-	printf("Write trailing data.\r\n");
-	write_to_flash(erase_end, sector_buf_post, append_len);
-	flush_cpu_dcache();
-
-	printf("Phase 4: Writing new data to flash.\r\n");
-	write_to_flash(addr, (unsigned char *) bitbang_buffer, len);
-	flush_cpu_dcache();
+	write_to_flash_arb(addr, len, sector_buf_pre, sector_buf_post);
 
 	memcpy(bus_buffer, (void *) addr, len);
 	printf("Phase 5: Comparing memory bus to received data.\r\n");
@@ -224,6 +195,40 @@ int write_sfl(unsigned long addr, unsigned long len, unsigned long crc) {
 	return 0;
 }
 
+static void write_to_flash_arb(unsigned int addr, unsigned int len, unsigned char * prepend_buf, unsigned char * append_buf) {
+	printf("Phase 3: Erase flash region.\r\n");
+	/* All end ptrs are "one past the last byte used for data of the
+	previous start ptr". */
+	unsigned int erase_addr = addr;
+	unsigned int erase_end = erase_addr + len;
+	unsigned int sector_start = erase_addr & ~(SPIFLASH_SECTOR_SIZE - 1);
+	unsigned int sector_end = (erase_end & ~(SPIFLASH_SECTOR_SIZE - 1)) + SPIFLASH_SECTOR_SIZE;
+	unsigned int prepend_len = erase_addr - sector_start;
+	unsigned int append_len = sector_end - erase_end;
+
+	memcpy(prepend_buf, (void *) sector_start, prepend_len);
+	memcpy(append_buf, (void *) erase_end, append_len);
+	erase_flash_sector(sector_start);
+	printf("Write leading data.\r\n");
+	write_to_flash(sector_start, prepend_buf, prepend_len);
+	flush_cpu_dcache();
+
+	unsigned int middle_sectors = sector_start + SPIFLASH_SECTOR_SIZE;
+
+	while(middle_sectors < sector_end) {
+		erase_flash_sector(middle_sectors);
+		middle_sectors += SPIFLASH_SECTOR_SIZE;
+	}
+
+	printf("Write trailing data.\r\n");
+	write_to_flash(erase_end, append_buf, append_len);
+	flush_cpu_dcache();
+
+	printf("Phase 4: Writing new data to flash.\r\n");
+	write_to_flash(addr, (unsigned char *) bitbang_buffer, len);
+	flush_cpu_dcache();
+}
+
 
 
 

From 220a547c31608e23c5ee57922bbc52f6984f6958 Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Sun, 20 Aug 2017 03:32:37 -0400
Subject: [PATCH 19/32] Add CRC32 support to upload (and helper script).

---
 firmware/flash.c |  9 +++++++++
 getcrc32.py      | 30 ++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+)
 create mode 100644 getcrc32.py

diff --git a/firmware/flash.c b/firmware/flash.c
index 09feac19..50f44f19 100644
--- a/firmware/flash.c
+++ b/firmware/flash.c
@@ -12,6 +12,7 @@
 #include <time.h>
 #include <console.h>
 #include <spiflash.h>
+#include <crc.h>
 #include <system.h>
 #include "ci.h"
 
@@ -148,7 +149,9 @@ int write_to_buf(const char * buf, const int buf_size, const int eof, void * con
 int write_xmodem(unsigned long addr, unsigned long len, unsigned long crc) {
 	flash_writer_t writer = { bitbang_buffer, len, 0, sizeof(bitbang_buffer)/sizeof(bitbang_buffer[0]) };
 	serial_handle_t uart;
+	unsigned int calc_crc;
 
+	printf("Phase 1: Receive file (Please start XMODEM transmission).\r\n");
 	serial_init(0, 0, &uart);
 	int rc = xmodem_rx(write_to_buf, xmodem_buffer, &writer, uart, XMODEM_1K);
 	serial_close(&uart);
@@ -158,6 +161,12 @@ int write_xmodem(unsigned long addr, unsigned long len, unsigned long crc) {
 	}
 
 	// Do CRC check. Return if no match.
+	printf("Phase 2: CRC check.\r\n");
+	calc_crc = crc32((unsigned char *) bitbang_buffer, len);
+	if(crc != calc_crc) {
+		printf("CRC failed (expected %08x, got %08x)\n", crc, calc_crc);
+		return -1;
+	}
 
 	write_to_flash_arb(addr, len, sector_buf_pre, sector_buf_post);
 
diff --git a/getcrc32.py b/getcrc32.py
new file mode 100644
index 00000000..a9dd1270
--- /dev/null
+++ b/getcrc32.py
@@ -0,0 +1,30 @@
+#!/usr/bin/env python3
+
+import os
+import argparse
+import binascii
+
+def main():
+    parser = argparse.ArgumentParser(description="Print file length and CRC32.")
+    parser.add_argument("-n", help="List filenames of input files.")
+    parser.add_argument("-l", help="List length of input files.")
+    parser.add_argument("files", metavar="f", type=str, nargs="+",
+        help="Files to calculate CRC32")
+
+    args = parser.parse_args()
+
+    lens = []
+    crcs = []
+    for f in args.files:
+        lens.append(os.path.getsize(f))
+        with open(f, "rb") as fp:
+            crcs.append(binascii.crc32(fp.read()))
+
+    for n in range(len(args.files)):
+        print("{}: {} {:#0X}".format(args.files[n], lens[n], crcs[n]))
+
+
+
+
+if __name__ == "__main__":
+    main()

From ab9443ce13d3d472af299a64e4cf52d9b79c4ae4 Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Thu, 24 Aug 2017 04:09:16 -0400
Subject: [PATCH 20/32] Bump third_party/libmodem up to documentation commits.

---
 third_party/libmodem | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/third_party/libmodem b/third_party/libmodem
index 316bb2e2..224b25b0 160000
--- a/third_party/libmodem
+++ b/third_party/libmodem
@@ -1 +1 @@
-Subproject commit 316bb2e270b3e0b9f1bec6478a6c3a2d63d0d804
+Subproject commit 224b25b0d4bd21a2490ddd60a26b12545993fa45

From 7dae4bc6fa200e16bc63006a0435d56e77b95bd9 Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Wed, 6 Sep 2017 02:21:09 -0400
Subject: [PATCH 21/32] libmodem uses Meson build system now. Integrate
 libmodem build like libuip.

---
 firmware/Makefile          | 12 +++---------
 firmware/modem/Makefile    | 17 +++++++++++++++++
 firmware/modem/Makefile.mk |  5 +++++
 firmware/modem/README.md   | 12 ++++++++++++
 make.py                    |  1 +
 third_party/libmodem       |  2 +-
 6 files changed, 39 insertions(+), 10 deletions(-)
 create mode 100644 firmware/modem/Makefile
 create mode 100644 firmware/modem/Makefile.mk
 create mode 100644 firmware/modem/README.md

diff --git a/firmware/Makefile b/firmware/Makefile
index 95ff5543..d2e50af7 100644
--- a/firmware/Makefile
+++ b/firmware/Makefile
@@ -16,9 +16,6 @@ CFLAGS += -DPLATFORM_$(UPLATFORM) -DTARGET_$(UTARGET)
 BUILD_DIRECTORY=$(BUILDINC_DIRECTORY)/../../
 FIRMBUILD_DIRECTORY=$(BUILD_DIRECTORY)/software/firmware
 
-LIBMODEM_DIR=../../../../third_party/libmodem
-LIBMODEM=$(LIBMODEM_DIR)/build/hdmi2usb-lm32/libmodem.a
-
 OBJECTS=\
 	bist.o \
 	ci.o \
@@ -57,7 +54,6 @@ OBJECTS=\
 CFLAGS += \
 	-I$(FIRMWARE_DIRECTORY) \
 	-I$(BUILD_DIRECTORY)/software/firmware \
-	-I$(LIBMODEM_DIR)/src
 
 CFLAGS += \
 	-Wall \
@@ -67,6 +63,7 @@ CFLAGS += \
 
 
 include $(UIP_DIRECTORY)/Makefile.mk
+include $(MODEM_DIRECTORY)/Makefile.mk
 
 LDFLAGS += \
 
@@ -79,7 +76,7 @@ all: firmware.bin firmware.fbi
 	$(OBJCOPY) -O binary $< $@
 	chmod -x $@
 
-firmware.elf: $(FIRMWARE_DIRECTORY)/linker.ld $(OBJECTS) $(LIBMODEM)
+firmware.elf: $(FIRMWARE_DIRECTORY)/linker.ld $(OBJECTS)
 
 %.elf: ../libbase/crt0-$(CPU).o ../libbase/libbase-nofloat.a ../libcompiler_rt/libcompiler_rt.a ../uip/libuip.a
 	$(LD) $(LDFLAGS) \
@@ -93,7 +90,7 @@ firmware.elf: $(FIRMWARE_DIRECTORY)/linker.ld $(OBJECTS) $(LIBMODEM)
 		-lcompiler_rt \
 		-L../uip \
 		-luip \
-		-L$(LIBMODEM_DIR)/build/hdmi2usb-lm32 \
+		-L../modem \
 		-lmodem
 	chmod -x $@
 
@@ -139,7 +136,4 @@ $(FIRMBUILD_DIRECTORY)/hdmi_in1.c: $(FIRMWARE_DIRECTORY)/hdmi_in0.c $(FIRMWARE_D
 	# Check the files exist
 	[ -e $(FIRMBUILD_DIRECTORY)/hdmi_in1.c ]
 
-$(LIBMODEM): $(LIBMODEM_DIR)/src/*.c
-	cd $(LIBMODEM_DIR) && scons TARGET_OS=hdmi2usb-lm32 BUILD_TYPE=Release HDMI2USB_BUILD=$(BUILD_DIRECTORY)
-
 .PHONY: all clean libs version_data
diff --git a/firmware/modem/Makefile b/firmware/modem/Makefile
new file mode 100644
index 00000000..888ba7f7
--- /dev/null
+++ b/firmware/modem/Makefile
@@ -0,0 +1,17 @@
+include ../include/generated/variables.mak
+include $(SOC_DIRECTORY)/software/common.mak
+
+VPATH=$(MODEM_DIRECTORY)
+
+include $(MODEM_DIRECTORY)/Makefile.mk
+
+libmodem.a: $(LIBMODEMDIR)/build.ninja ninja-hack
+	ninja -f $<
+
+# meson doesn't understand vpath
+REALSRCDIR=$(MODEM_DIRECTORY)/$(LIBMODEMDIR)
+
+$(LIBMODEMDIR)/build.ninja: $(LIBMODEMDIR)/meson.build $(LIBMODEMDIR)/targets/hdmi2usb-$(CPU).txt
+	meson.py $(LIBMODEMDIR) $(REALSRCDIR) --cross-file=$(REALSRCDIR)/targets/hdmi2usb-$(CPU).txt
+
+.PHONY: ninja-hack
diff --git a/firmware/modem/Makefile.mk b/firmware/modem/Makefile.mk
new file mode 100644
index 00000000..e2502b42
--- /dev/null
+++ b/firmware/modem/Makefile.mk
@@ -0,0 +1,5 @@
+LIBMODEMDIR=../../third_party/libmodem
+MODEMDIR=.
+
+CFLAGS += \
+	-I$(MODEMDIR)/$(LIBMODEMDIR)/src
diff --git a/firmware/modem/README.md b/firmware/modem/README.md
new file mode 100644
index 00000000..fad40344
--- /dev/null
+++ b/firmware/modem/README.md
@@ -0,0 +1,12 @@
+`libmodem` currently uses a separate build system from the rest of HDMI2USB.
+
+The purpose of this directory is to provide a make wrapper around `libmodem`
+that Litex picks up as a dependency.
+
+When building `libmodem` as a dependency of HDMI2USB, there are four directories
+used (relative to `$HDMI2USB_ROOT` and for a given `$TARGET`):
+
+* `$HDMI2USB_ROOT/firmware/modem`: This directory, where Makefiles live.
+* `$HDMI2USB_ROOT/third_party/libmodem`: `libmodem` source code.
+* `$HDMI2USB_ROOT/build/$TARGET/third_party/libmodem`: Meson output/`build.ninja` are generated here.
+* `$HDMI2USB_ROOT/build/$TARGET/software/modem`: Object files and `libmodem.a` are generated here.
diff --git a/make.py b/make.py
index d6b781be..ec4fda58 100755
--- a/make.py
+++ b/make.py
@@ -117,6 +117,7 @@ def main():
     builder = Builder(soc, **buildargs)
     if not args.no_compile_firmware or args.override_firmware:
         builder.add_software_package("uip", "{}/firmware/uip".format(os.getcwd()))
+        builder.add_software_package("modem", "{}/firmware/modem".format(os.getcwd()))
         builder.add_software_package("firmware", "{}/firmware".format(os.getcwd()))
     vns = builder.build(**dict(args.build_option))
 
diff --git a/third_party/libmodem b/third_party/libmodem
index 224b25b0..a3d26a03 160000
--- a/third_party/libmodem
+++ b/third_party/libmodem
@@ -1 +1 @@
-Subproject commit 224b25b0d4bd21a2490ddd60a26b12545993fa45
+Subproject commit a3d26a03fff4c03d9c7d5b6662ca7c22f489c434

From 01b6d8f116a8d1b61600b971480df960f6c1cd3f Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Thu, 7 Sep 2017 22:11:51 -0400
Subject: [PATCH 22/32] Fix libmodem compilation so that hdmi2usb_dir is set
 properly, uses only single build directory.

---
 firmware/modem/Makefile | 6 +++---
 third_party/libmodem    | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/firmware/modem/Makefile b/firmware/modem/Makefile
index 888ba7f7..28698ff3 100644
--- a/firmware/modem/Makefile
+++ b/firmware/modem/Makefile
@@ -5,13 +5,13 @@ VPATH=$(MODEM_DIRECTORY)
 
 include $(MODEM_DIRECTORY)/Makefile.mk
 
-libmodem.a: $(LIBMODEMDIR)/build.ninja ninja-hack
+libmodem.a: build.ninja ninja-hack
 	ninja -f $<
 
 # meson doesn't understand vpath
 REALSRCDIR=$(MODEM_DIRECTORY)/$(LIBMODEMDIR)
 
-$(LIBMODEMDIR)/build.ninja: $(LIBMODEMDIR)/meson.build $(LIBMODEMDIR)/targets/hdmi2usb-$(CPU).txt
-	meson.py $(LIBMODEMDIR) $(REALSRCDIR) --cross-file=$(REALSRCDIR)/targets/hdmi2usb-$(CPU).txt
+build.ninja: $(LIBMODEMDIR)/meson.build $(LIBMODEMDIR)/targets/hdmi2usb-$(CPU).txt
+	meson.py . $(REALSRCDIR) -Dhdmi2usb_dir=$(BUILDINC_DIRECTORY)/../.. --cross-file=$(REALSRCDIR)/targets/hdmi2usb-$(CPU).txt
 
 .PHONY: ninja-hack
diff --git a/third_party/libmodem b/third_party/libmodem
index a3d26a03..2906c00c 160000
--- a/third_party/libmodem
+++ b/third_party/libmodem
@@ -1 +1 @@
-Subproject commit a3d26a03fff4c03d9c7d5b6662ca7c22f489c434
+Subproject commit 2906c00ccb404bd49aec053c5047d0554673aeef

From 0e3b1380ee1677939751ebd6667a680b5701cddb Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Mon, 11 Sep 2017 18:09:58 -0400
Subject: [PATCH 23/32] Fix libmodem include path, remove scons remnants.

---
 Makefile                   | 2 --
 firmware/modem/Makefile.mk | 2 +-
 2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/Makefile b/Makefile
index c11664db..83394750 100644
--- a/Makefile
+++ b/Makefile
@@ -203,7 +203,6 @@ firmware-clear: firmware-clear-$(PLATFORM)
 .PHONY: firmware-load-$(PLATFORM) firmware-flash-$(PLATFORM) firmware-connect-$(PLATFORM) firmware-clear-$(PLATFORM)
 
 firmware-clean:
-	cd third_party/libmodem && scons TARGET_OS=hdmi2usb-lm32 HDMI2USB_BUILD=$(PWD)/$(TARGET_BUILD_DIR) -c
 	rm -rf $(TARGET_BUILD_DIR)/software
 
 .PHONY: firmware-cmd $(FIRMWARE_FILEBASE).bin firmware firmware-load firmware-flash firmware-connect firmware-clean
@@ -358,7 +357,6 @@ reset: reset-$(PLATFORM)
 
 clean:
 	rm build/cache.mk
-	cd third_party/libmodem && scons TARGET_OS=hdmi2usb-lm32 HDMI2USB_BUILD=$(PWD)/$(TARGET_BUILD_DIR) -c
 	rm -rf $(TARGET_BUILD_DIR)
 	py3clean . || rm -rf $$(find -name __pycache__)
 
diff --git a/firmware/modem/Makefile.mk b/firmware/modem/Makefile.mk
index e2502b42..6c07f3ad 100644
--- a/firmware/modem/Makefile.mk
+++ b/firmware/modem/Makefile.mk
@@ -2,4 +2,4 @@ LIBMODEMDIR=../../third_party/libmodem
 MODEMDIR=.
 
 CFLAGS += \
-	-I$(MODEMDIR)/$(LIBMODEMDIR)/src
+	-I$(MODEM_DIRECTORY)/$(LIBMODEMDIR)/src

From 308b27e49292271c34034a2f108a5dc27fbc3a21 Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Wed, 27 Sep 2017 02:36:15 -0400
Subject: [PATCH 24/32] Disable PIC option added by meson when compiling
 libmodem- crashes firmware.

---
 firmware/modem/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/firmware/modem/Makefile b/firmware/modem/Makefile
index 28698ff3..93dd3428 100644
--- a/firmware/modem/Makefile
+++ b/firmware/modem/Makefile
@@ -12,6 +12,6 @@ libmodem.a: build.ninja ninja-hack
 REALSRCDIR=$(MODEM_DIRECTORY)/$(LIBMODEMDIR)
 
 build.ninja: $(LIBMODEMDIR)/meson.build $(LIBMODEMDIR)/targets/hdmi2usb-$(CPU).txt
-	meson.py . $(REALSRCDIR) -Dhdmi2usb_dir=$(BUILDINC_DIRECTORY)/../.. --cross-file=$(REALSRCDIR)/targets/hdmi2usb-$(CPU).txt
+	meson.py . $(REALSRCDIR) -Db_staticpic=false -Dhdmi2usb_dir=$(BUILDINC_DIRECTORY)/../.. --cross-file=$(REALSRCDIR)/targets/hdmi2usb-$(CPU).txt
 
 .PHONY: ninja-hack

From 955cf6d09263e7aea2a45a84d0bf769e9a6ee747 Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Sat, 7 Oct 2017 10:33:59 -0400
Subject: [PATCH 25/32] Ensure firmware compiles successfully after merge.

---
 firmware/Makefile     |   1 +
 firmware/flash.c      |   2 +-
 firmware/spiflash.c   | 183 ++++++++++++++++++++++++++++++++++++++++++
 firmware/spiflash.h   |   9 +++
 gateware/spi_flash.py |   1 -
 5 files changed, 194 insertions(+), 2 deletions(-)
 create mode 100644 firmware/spiflash.c
 create mode 100644 firmware/spiflash.h

diff --git a/firmware/Makefile b/firmware/Makefile
index d2e50af7..2936bc77 100644
--- a/firmware/Makefile
+++ b/firmware/Makefile
@@ -41,6 +41,7 @@ OBJECTS=\
 	pll.o \
 	processor.o \
 	reboot.o \
+	spiflash.o \
 	stdio_wrap.o \
 	telnet.o \
 	tofe_eeprom.o \
diff --git a/firmware/flash.c b/firmware/flash.c
index 50f44f19..f571f5d7 100644
--- a/firmware/flash.c
+++ b/firmware/flash.c
@@ -1,6 +1,7 @@
 #include <generated/csr.h>
 #include <generated/mem.h>
 #if (defined CSR_SPIFLASH_BASE && defined SPIFLASH_PAGE_SIZE)
+#include "spiflash.h"
 #include "flash.h"
 
 #include <stdio.h>
@@ -11,7 +12,6 @@
 #include <uart.h>
 #include <time.h>
 #include <console.h>
-#include <spiflash.h>
 #include <crc.h>
 #include <system.h>
 #include "ci.h"
diff --git a/firmware/spiflash.c b/firmware/spiflash.c
new file mode 100644
index 00000000..c77dcf33
--- /dev/null
+++ b/firmware/spiflash.c
@@ -0,0 +1,183 @@
+#include <generated/csr.h>
+
+#if (defined CSR_SPIFLASH_BASE && defined SPIFLASH_PAGE_SIZE)
+
+#include "spiflash.h"
+
+#define PAGE_PROGRAM_CMD 0x02
+#define WRDI_CMD         0x04
+#define RDSR_CMD         0x05
+#define WREN_CMD         0x06
+#define RD_CMD           0x0b
+#define SE_CMD           0xd8
+
+#define BITBANG_CLK         (1 << 1)
+#define BITBANG_CS_N        (1 << 2)
+#define BITBANG_DQ_INPUT    (1 << 3) // This bit is only used for Dual/Quad SPI
+// flash, where MISO/MOSI pins are bidirectional depending on SPI flash command.
+// The bitbang interface does not support Dual/Quad reads.
+
+#define SR_WIP              1
+
+static void flash_write_byte(unsigned char b);
+static void flash_write_addr(unsigned int addr);
+static void wait_for_device_ready(void);
+
+#define min(a,b)  (a>b?b:a)
+
+// flash_read/flash_write fcns make no assumptions on bitbang reg on entry.
+// They will all leave the bitbang reg as 0x00 on exit.
+// We latch on positive edge, so only Modes 0 and 3 supported.
+// FIXME: Bitbang commands that use the read/write primitives
+// leave ~CLK as 0 on exit, which is Mode 0 compatible only.
+// How should we handle Mode 3? Set-once global and mask?
+static unsigned char flash_read_byte(void)
+{
+    int i;
+    unsigned char b = 0;
+    spiflash_bitbang_write(BITBANG_DQ_INPUT); // ~CS_N ~CLK DQ_INPUT
+
+    for(i = 0; i < 8; i++) {
+        b <<= 1;
+        spiflash_bitbang_write(BITBANG_CLK | BITBANG_DQ_INPUT);
+        b |= spiflash_miso_read();
+        spiflash_bitbang_write(0           | BITBANG_DQ_INPUT);
+    }
+
+    spiflash_bitbang_write(0); // ~CS_N ~CLK
+    return b;
+}
+
+static void flash_write_byte(unsigned char b)
+{
+    int i;
+    spiflash_bitbang_write(0); // ~CS_N ~CLK
+
+    for(i = 0; i < 8; i++, b <<= 1) {
+
+        spiflash_bitbang_write((b & 0x80) >> 7);
+        spiflash_bitbang_write(((b & 0x80) >> 7) | BITBANG_CLK);
+    }
+
+    spiflash_bitbang_write(0); // ~CS_N ~CLK
+}
+
+static void flash_write_addr(unsigned int addr)
+{
+    int i;
+    spiflash_bitbang_write(0);
+
+    for(i = 0; i < 24; i++, addr <<= 1) {
+        spiflash_bitbang_write((addr & 0x800000) >> 23);
+        spiflash_bitbang_write(((addr & 0x800000) >> 23) | BITBANG_CLK);
+    }
+
+    spiflash_bitbang_write(0);
+}
+
+// Bitbang commands will have flash_read/write fcns set up the bitbang reg
+// on entry. On exit, bitbang command fcns will deassert CS_N bitbang
+// regs (required) and then disable bitbang interface.
+// XXX: write_to_flash_page leaves CS_N as 0. Why?
+static void wait_for_device_ready(void)
+{
+    unsigned char sr;
+    unsigned char i;
+    do {
+        sr = 0;
+        flash_write_byte(RDSR_CMD);
+        sr = flash_read_byte();
+        spiflash_bitbang_write(BITBANG_CS_N);
+    } while(sr & SR_WIP);
+}
+
+void erase_flash_sector(unsigned int addr)
+{
+    unsigned int sector_addr = addr & ~(SPIFLASH_SECTOR_SIZE - 1);
+
+    spiflash_bitbang_en_write(1);
+
+    wait_for_device_ready();
+
+    flash_write_byte(WREN_CMD);
+    spiflash_bitbang_write(BITBANG_CS_N);
+
+    flash_write_byte(SE_CMD);
+    flash_write_addr(sector_addr);
+    spiflash_bitbang_write(BITBANG_CS_N);
+
+    wait_for_device_ready();
+
+    spiflash_bitbang_en_write(0);
+}
+
+void read_from_flash(unsigned int addr, unsigned char *c, unsigned int len)
+{
+    unsigned int i;
+
+    spiflash_bitbang_en_write(1);
+
+    wait_for_device_ready();
+
+    flash_write_byte(RD_CMD);
+    flash_write_addr(addr);
+    (void) flash_read_byte(); // Higher-speed read has a dummy byte.
+    for(i = 0; i < len; i++)
+        *c++ = flash_read_byte();
+    spiflash_bitbang_write(BITBANG_CS_N);
+
+    wait_for_device_ready();
+
+    spiflash_bitbang_en_write(0);
+}
+
+void write_to_flash_page(unsigned int addr, const unsigned char *c, unsigned int len)
+{
+    unsigned int i;
+
+    if(len > SPIFLASH_PAGE_SIZE)
+        len = SPIFLASH_PAGE_SIZE;
+
+    spiflash_bitbang_en_write(1);
+
+    wait_for_device_ready();
+
+    flash_write_byte(WREN_CMD);
+    spiflash_bitbang_write(BITBANG_CS_N);
+    flash_write_byte(PAGE_PROGRAM_CMD);
+    flash_write_addr((unsigned int)addr);
+    for(i = 0; i < len; i++)
+        flash_write_byte(*c++);
+
+    spiflash_bitbang_write(BITBANG_CS_N);
+    spiflash_bitbang_write(0);
+
+    wait_for_device_ready();
+
+    spiflash_bitbang_en_write(0);
+}
+
+#define SPIFLASH_PAGE_MASK (SPIFLASH_PAGE_SIZE - 1)
+
+void write_to_flash(unsigned int addr, const unsigned char *c, unsigned int len)
+{
+   unsigned int written = 0;
+
+   if(addr & SPIFLASH_PAGE_MASK) {
+       written = min(SPIFLASH_PAGE_SIZE - (addr & SPIFLASH_PAGE_MASK), len);
+       write_to_flash_page(addr, c, written);
+       c += written;
+       addr += written;
+       len -= written;
+   }
+
+   while(len > 0) {
+       written = min(len, SPIFLASH_PAGE_SIZE);
+       write_to_flash_page(addr, c, written);
+       c += written;
+       addr += written;
+       len -= written;
+   }
+}
+
+#endif /* CSR_SPIFLASH_BASE && SPIFLASH_PAGE_SIZE */
diff --git a/firmware/spiflash.h b/firmware/spiflash.h
new file mode 100644
index 00000000..bfbd7672
--- /dev/null
+++ b/firmware/spiflash.h
@@ -0,0 +1,9 @@
+#ifndef __SPIFLASH_H
+#define __SPIFLASH_H
+
+void write_to_flash_page(unsigned int addr, const unsigned char *c, unsigned int len);
+void erase_flash_sector(unsigned int addr);
+void write_to_flash(unsigned int addr, const unsigned char *c, unsigned int len);
+void read_from_flash(unsigned int addr, unsigned char *c, unsigned int len);
+
+#endif /* __SPIFLASH_H */
diff --git a/gateware/spi_flash.py b/gateware/spi_flash.py
index 02f3dcfb..d85e5bdc 100644
--- a/gateware/spi_flash.py
+++ b/gateware/spi_flash.py
@@ -258,4 +258,3 @@ def SpiFlash(pads, *args, **kw):
         return SpiFlashSingle(pads, *args, **kw)
     else:
         return SpiFlashDualQuad(pads, *args, **kw)
-

From bc8dd4784d44ca9506f60d7efadf4cf52bdfff6e Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Wed, 13 Dec 2017 10:44:11 -0500
Subject: [PATCH 26/32] Parameterize meson executable name, which may be
 available as 'meson' or 'meson.py'.

---
 Makefile                | 3 +++
 firmware/modem/Makefile | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index 83394750..50d4bc1f 100644
--- a/Makefile
+++ b/Makefile
@@ -7,6 +7,9 @@ endif
 PYTHON ?= python
 export PYTHON
 
+MESON ?= meson
+export MESON
+
 PLATFORM ?= opsis
 export PLATFORM
 # Default board
diff --git a/firmware/modem/Makefile b/firmware/modem/Makefile
index 93dd3428..8398fb96 100644
--- a/firmware/modem/Makefile
+++ b/firmware/modem/Makefile
@@ -12,6 +12,6 @@ libmodem.a: build.ninja ninja-hack
 REALSRCDIR=$(MODEM_DIRECTORY)/$(LIBMODEMDIR)
 
 build.ninja: $(LIBMODEMDIR)/meson.build $(LIBMODEMDIR)/targets/hdmi2usb-$(CPU).txt
-	meson.py . $(REALSRCDIR) -Db_staticpic=false -Dhdmi2usb_dir=$(BUILDINC_DIRECTORY)/../.. --cross-file=$(REALSRCDIR)/targets/hdmi2usb-$(CPU).txt
+	$(MESON) . $(REALSRCDIR) -Db_staticpic=false -Dhdmi2usb_dir=$(BUILDINC_DIRECTORY)/../.. --cross-file=$(REALSRCDIR)/targets/hdmi2usb-$(CPU).txt
 
 .PHONY: ninja-hack

From 02fbd6628b948abcf82b94a1db3a073db7a1999e Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Wed, 13 Dec 2017 10:45:15 -0500
Subject: [PATCH 27/32] Add meson as travis CI dependency to build libmodem.

---
 .travis.yml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/.travis.yml b/.travis.yml
index 00bec819..81b1c73e 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -14,6 +14,7 @@ addons:
     - libftdi-dev
     - libreadline-dev
     - libusb-1.0-0-dev
+    - meson
     - python-yaml
     - realpath
     - util-linux

From 02296eb015156d6ca1707a23eae3c9b24d5a1010 Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Wed, 13 Dec 2017 11:12:19 -0500
Subject: [PATCH 28/32] Fix travis CI dependencies.

---
 .travis.yml | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/.travis.yml b/.travis.yml
index 81b1c73e..cac740f1 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -14,7 +14,7 @@ addons:
     - libftdi-dev
     - libreadline-dev
     - libusb-1.0-0-dev
-    - meson
+    - python3-pip
     - python-yaml
     - realpath
     - util-linux
@@ -27,6 +27,12 @@ env:
    - HDMI2USB_UDEV_IGNORE=1
    - CLEAN_CHECK=1
 
+before_install:
+ - wget https://github.com/ninja-build/ninja/releases/download/v1.8.2/ninja-linux.zip -O /tmp/ninja.zip
+ - unzip -d ninja-1.8.2 /tmp/ninja.zip
+ - export PATH=$PATH:$PWD/ninja-1.8.2/
+ - pip3 install --user meson
+
 install:
  - export CPU="$C"
  - export PLATFORMS="$P"

From 96428a293b73be483c4455186b9c0d958d582f6a Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Thu, 14 Dec 2017 12:19:06 -0500
Subject: [PATCH 29/32] CC needs to be set to a dummy value for meson. Add
 comment explaining.

---
 firmware/modem/Makefile | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/firmware/modem/Makefile b/firmware/modem/Makefile
index 8398fb96..0e5f19fb 100644
--- a/firmware/modem/Makefile
+++ b/firmware/modem/Makefile
@@ -12,6 +12,10 @@ libmodem.a: build.ninja ninja-hack
 REALSRCDIR=$(MODEM_DIRECTORY)/$(LIBMODEMDIR)
 
 build.ninja: $(LIBMODEMDIR)/meson.build $(LIBMODEMDIR)/targets/hdmi2usb-$(CPU).txt
-	$(MESON) . $(REALSRCDIR) -Db_staticpic=false -Dhdmi2usb_dir=$(BUILDINC_DIRECTORY)/../.. --cross-file=$(REALSRCDIR)/targets/hdmi2usb-$(CPU).txt
+	# If $CC was exported at all from a parent, make will set it to $(CC_quiet).
+	# This will confuse meson and cause the build to fail, so set it to a dummy
+	# value for the time being. Since this is a cross-build, cc won't be used
+	# after meson runs.
+	CC=cc $(MESON) . $(REALSRCDIR) -Db_staticpic=false -Dhdmi2usb_dir=$(BUILDINC_DIRECTORY)/../.. --cross-file=$(REALSRCDIR)/targets/hdmi2usb-$(CPU).txt
 
 .PHONY: ninja-hack

From 2f87f9d507a4353402ca32ab36d6dd59dc8f52fe Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Thu, 14 Dec 2017 12:45:46 -0500
Subject: [PATCH 30/32] Update libmodem to include hdmi2usb-or1k backend.

---
 third_party/libmodem | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/third_party/libmodem b/third_party/libmodem
index 2906c00c..a3a2f804 160000
--- a/third_party/libmodem
+++ b/third_party/libmodem
@@ -1 +1 @@
-Subproject commit 2906c00ccb404bd49aec053c5047d0554673aeef
+Subproject commit a3a2f804cd3b88cf3eb9ec921569780ab6f65b87

From 3f0c3299155c18d4cd464b12749c4eb31b4d11aa Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Thu, 14 Dec 2017 12:55:40 -0500
Subject: [PATCH 31/32] Improve conditional compilation for bitbang_test.

---
 firmware/ci.c    | 4 ++--
 firmware/flash.c | 2 ++
 firmware/flash.h | 2 ++
 3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/firmware/ci.c b/firmware/ci.c
index dce67aa9..319b2ac3 100644
--- a/firmware/ci.c
+++ b/firmware/ci.c
@@ -175,7 +175,7 @@ static void help_debug(void)
 #endif
 	wputs("  debug dna                      - show Board's DNA");
 	wputs("  debug edid                     - dump monitor EDID");
-#ifdef CSR_SPIFLASH_BASE
+#if defined(CSR_SPIFLASH_BASE) && defined(FLASH_BOOT_ADDRESS)
 	wputs("  debug spiflash                 - test bitbang write");
 #endif
 #ifdef CSR_CAS_BASE
@@ -1358,7 +1358,7 @@ void ci_service(void)
 #endif
 			if(found == 0)
 				wprintf("%s port has no EDID capabilities\r\n", token);
-#ifdef CSR_SPIFLASH_BASE
+#if defined(CSR_SPIFLASH_BASE) && defined(FLASH_BOOT_ADDRESS)
 		} else if(strcmp(token, "spiflash") == 0) {
 				bitbang_test();
 #endif
diff --git a/firmware/flash.c b/firmware/flash.c
index f571f5d7..f74db568 100644
--- a/firmware/flash.c
+++ b/firmware/flash.c
@@ -85,6 +85,7 @@ void flash_test(void) {
 	mr(0x20000000, test_size);
 }
 
+#ifdef FLASH_BOOT_ADDRESS
 void bitbang_test(void) {
 	unsigned int *flashbase;
 	unsigned int length;
@@ -122,6 +123,7 @@ void bitbang_test(void) {
 
 	erase_flash_sector((unsigned int) free_start);
 }
+#endif
 
 
 // XMODEM:
diff --git a/firmware/flash.h b/firmware/flash.h
index eb40131f..5df3b3c6 100644
--- a/firmware/flash.h
+++ b/firmware/flash.h
@@ -2,7 +2,9 @@
 #define __FLASH_H
 
 void flash_test(void);
+#ifdef FLASH_BOOT_ADDRESS
 void bitbang_test(void);
+#endif
 
 #ifdef CSR_UART_BASE
 int write_xmodem(unsigned long addr, unsigned long len, unsigned long crc);

From 6a4935aa34a5104e04db3185c22ba4571160428b Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Thu, 14 Dec 2017 13:14:05 -0500
Subject: [PATCH 32/32] Fix bad libmodem update.

---
 third_party/libmodem | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/third_party/libmodem b/third_party/libmodem
index a3a2f804..1499a0bc 160000
--- a/third_party/libmodem
+++ b/third_party/libmodem
@@ -1 +1 @@
-Subproject commit a3a2f804cd3b88cf3eb9ec921569780ab6f65b87
+Subproject commit 1499a0bcc545668413a21ed3ec43e102b46621fa