pbio/os: Add context to process.

When using the same thread for multiple processes it can be useful to have a reference to the state that belongs to that instance.

This avoids having to use several cases of CONTAINER_OF to get to the parent of a state, which is not always available.

This also brings it one step closer to pbio tasks, which we might model in this way too.

Author: laurensvalk

lib/pbio/drv/charger/charger_mp2639a.c

@@ -178,7 +178,7 @@ static bool read_chg(void) {
 
 static pbio_os_process_t pbdrv_charger_mp2639a_process;
 
-pbio_error_t pbdrv_charger_mp2639a_process_thread(pbio_os_state_t *state) {
+pbio_error_t pbdrv_charger_mp2639a_process_thread(pbio_os_state_t *state, void *context) {
 
     static pbio_os_timer_t timer;
 
@@ -282,7 +282,7 @@ pbio_error_t pbdrv_charger_mp2639a_process_thread(pbio_os_state_t *state) {
 
 void pbdrv_charger_init(void) {
     pbdrv_init_busy_up();
-    pbio_os_start_process(&pbdrv_charger_mp2639a_process, pbdrv_charger_mp2639a_process_thread);
+    pbio_os_start_process(&pbdrv_charger_mp2639a_process, pbdrv_charger_mp2639a_process_thread, NULL);
 }
 
 #endif // PBDRV_CONFIG_CHARGER_MP2639A

lib/pbio/include/pbio/os.h

@@ -87,7 +87,7 @@ bool pbio_os_timer_is_expired(pbio_os_timer_t *timer);
  */
 typedef uint32_t pbio_os_state_t;
 
-typedef pbio_error_t (*pbio_os_process_func_t)(pbio_os_state_t *state);
+typedef pbio_error_t (*pbio_os_process_func_t)(pbio_os_state_t *state, void *context);
 
 typedef struct _pbio_os_process_t pbio_os_process_t;
 
@@ -107,6 +107,10 @@ struct _pbio_os_process_t {
      * The protothread.
      */
     pbio_os_process_func_t func;
+    /**
+     * Context passed on each call to the protothread.
+     */
+    void *context;
     /**
      * Most recent result of running one iteration of the protothread.
      */
@@ -187,7 +191,7 @@ void pbio_os_run_while_idle(void);
 
 void pbio_os_request_poll(void);
 
-void pbio_os_start_process(pbio_os_process_t *process, pbio_os_process_func_t func);
+void pbio_os_start_process(pbio_os_process_t *process, pbio_os_process_func_t func, void *context);
 
 /**
  * Disables interrupts and returns the previous interrupt state.

lib/pbio/src/os.c

@@ -53,8 +53,9 @@ static pbio_os_process_t *process_list = NULL;
  *
  * @param process   The process to start.
  * @param func      The process thread function.
+ * @param context   The context to pass to the process.
  */
-void pbio_os_start_process(pbio_os_process_t *process, pbio_os_process_func_t func) {
+void pbio_os_start_process(pbio_os_process_t *process, pbio_os_process_func_t func, void *context) {
 
     // Add the new process to the end of the list.
     pbio_os_process_t *last = process_list;
@@ -69,6 +70,7 @@ void pbio_os_start_process(pbio_os_process_t *process, pbio_os_process_func_t fu
 
     // Initialize the process.
     process->func = func;
+    process->context = context;
     process->next = NULL;
     process->err = PBIO_ERROR_AGAIN;
     process->state = 0;
@@ -103,7 +105,7 @@ bool pbio_os_run_processes_once(void) {
     while (process) {
         // Run one iteration of the process if not yet completed or errored.
         if (process->err == PBIO_ERROR_AGAIN) {
-            process->err = process->func(&process->state);
+            process->err = process->func(&process->state, process->context);
         }
         process = process->next;
     }