diff options
Diffstat (limited to 'core/cortex-m/task.c')
| -rw-r--r-- | core/cortex-m/task.c | 142 |
1 files changed, 72 insertions, 70 deletions
diff --git a/core/cortex-m/task.c b/core/cortex-m/task.c index c48a5e3068..485e58e06d 100644 --- a/core/cortex-m/task.c +++ b/core/cortex-m/task.c @@ -5,8 +5,8 @@ /* Task scheduling / events module for Chrome EC operating system */ -#include "config.h" #include "atomic.h" +#include "common.h" #include "console.h" #include "cpu.h" #include "link_defs.h" @@ -64,20 +64,23 @@ extern int __task_start(int *task_stack_ready); /* Idle task. Executed when no tasks are ready to be scheduled. */ void __idle(void) { - /* Print when the idle task starts. This is the lowest priority task, + /* + * Print when the idle task starts. This is the lowest priority task, * so this only starts once all other tasks have gotten a chance to do - * their task inits and have gone to sleep. */ + * their task inits and have gone to sleep. + */ cprintf(CC_TASK, "[%T idle task started]\n"); while (1) { - /* Wait for the next irq event. This stops the CPU clock - * (sleep / deep sleep, depending on chip config). */ + /* + * Wait for the next irq event. This stops the CPU clock + * (sleep / deep sleep, depending on chip config). + */ asm("wfi"); } } #endif /* !CONFIG_LOW_POWER_IDLE */ - static void task_exit_trap(void) { int i = task_get_current(); @@ -87,7 +90,6 @@ static void task_exit_trap(void) task_wait_event(-1); } - /* Startup parameters for all tasks. */ #define TASK(n, r, d, s) { \ .r0 = (uint32_t)d, \ @@ -109,7 +111,6 @@ static const struct { static task_ tasks[TASK_ID_COUNT]; /* Stacks for all tasks */ -/* TODO: variable-size stacks */ #define TASK(n, r, d, s) + s #include TASK_LIST uint8_t task_stacks[0 @@ -128,7 +129,8 @@ uint32_t scratchpad[17]; static task_ *current_task = (task_ *)scratchpad; -/* Should IRQs chain to svc_handler()? This should be set if either of the +/* + * Should IRQs chain to svc_handler()? This should be set if either of the * following is true: * * 1) Task scheduling has started, and task profiling is enabled. Task @@ -136,11 +138,12 @@ static task_ *current_task = (task_ *)scratchpad; * * 2) An event was set by an interrupt; this could result in a higher-priority * task unblocking. After checking for a task switch, svc_handler() will clear - * the flag (unless profiling is also enabled; then the flag remains set). */ + * the flag (unless profiling is also enabled; then the flag remains set). + */ static int need_resched_or_profiling = 0; -/** - * bitmap of all tasks ready to be run +/* + * Bitmap of all tasks ready to be run. * * Currently all tasks are enabled at startup. */ @@ -153,19 +156,16 @@ static inline task_ *__task_id_to_ptr(task_id_t id) return tasks + id; } - void interrupt_disable(void) { asm("cpsid i"); } - void interrupt_enable(void) { asm("cpsie i"); } - inline int in_interrupt_context(void) { int ret; @@ -174,12 +174,11 @@ inline int in_interrupt_context(void) return ret; } - inline int get_interrupt_context(void) { int ret; asm("mrs %0, ipsr \n":"=r"(ret)); /* read exception number */ - return ret & 0x1ff; /* exception bits are the 9 LSB */ + return ret & 0x1ff; /* exception bits are the 9 LSB */ } task_id_t task_get_current(void) @@ -193,14 +192,14 @@ uint32_t *task_get_event_bitmap(task_id_t tskid) return &tsk->events; } - int task_start_called(void) { return start_called; } - -/* Scheduling system call */ +/** + * Scheduling system call + */ void svc_handler(int desched, task_id_t resched) { task_ *current, *next; @@ -209,14 +208,18 @@ void svc_handler(int desched, task_id_t resched) uint64_t t; #endif - /* Push the priority to -1 until the return, to avoid being - * interrupted */ + /* + * Push the priority to -1 until the return, to avoid being + * interrupted. + */ asm volatile("cpsid f\n" "isb\n"); #ifdef CONFIG_TASK_PROFILING - /* SVCall isn't triggered via DECLARE_IRQ(), so it needs to track its - * start time explicitly. */ + /* + * SVCall isn't triggered via DECLARE_IRQ(), so it needs to track its + * start time explicitly. + */ if (exc == 0xb) { exc_start_time = get_time().val; svc_calls++; @@ -245,13 +248,17 @@ void svc_handler(int desched, task_id_t resched) t = get_time().val; exc_total_time += (t - exc_start_time); - /* Bill the current task for time between the end of the last interrupt - * and the start of this one. */ + /* + * Bill the current task for time between the end of the last interrupt + * and the start of this one. + */ current->runtime += (exc_start_time - exc_end_time); exc_end_time = t; #else - /* Don't chain here from interrupts until the next time an interrupt - * sets an event. */ + /* + * Don't chain here from interrupts until the next time an interrupt + * sets an event. + */ need_resched_or_profiling = 0; #endif @@ -267,13 +274,14 @@ void svc_handler(int desched, task_id_t resched) __switchto(current, next); } - void __schedule(int desched, int resched) { register int p0 asm("r0") = desched; register int p1 asm("r1") = resched; - /* TODO: remove hardcoded opcode. SWI is not compiled properly for - * ARMv7-M on our current chroot toolchain. */ + /* + * TODO: remove hardcoded opcode. SWI is not compiled properly for + * ARMv7-M on our current chroot toolchain. + */ asm(".hword 0xdf00 @swi 0"::"r"(p0),"r"(p1)); } @@ -281,19 +289,25 @@ void __schedule(int desched, int resched) #ifdef CONFIG_TASK_PROFILING void task_start_irq_handler(void *excep_return) { - /* Get time before checking depth, in case this handler is - * pre-empted */ + /* + * Get time before checking depth, in case this handler is + * pre-empted. + */ uint64_t t = get_time().val; int irq = get_interrupt_context() - 16; - /* Track IRQ distribution. No need for atomic add, because an IRQ - * can't pre-empt itself. */ + /* + * Track IRQ distribution. No need for atomic add, because an IRQ + * can't pre-empt itself. + */ if (irq < ARRAY_SIZE(irq_dist)) irq_dist[irq]++; - /* Continue iff a rescheduling event happened or profiling is active, + /* + * Continue iff a rescheduling event happened or profiling is active, * and we are not called from another exception (this must match the - * logic for when we chain to svc_handler() below). */ + * logic for when we chain to svc_handler() below). + */ if (!need_resched_or_profiling || (((uint32_t)excep_return & 0xf) == 1)) return; @@ -301,18 +315,18 @@ void task_start_irq_handler(void *excep_return) } #endif - void task_resched_if_needed(void *excep_return) { - /* Continue iff a rescheduling event happened or profiling is active, - * and we are not called from another exception. */ + /* + * Continue iff a rescheduling event happened or profiling is active, + * and we are not called from another exception. + */ if (!need_resched_or_profiling || (((uint32_t)excep_return & 0xf) == 1)) return; svc_handler(0, 0); } - static uint32_t __wait_evt(int timeout_us, task_id_t resched) { task_ *tsk = current_task; @@ -339,7 +353,6 @@ static uint32_t __wait_evt(int timeout_us, task_id_t resched) return evt; } - uint32_t task_set_event(task_id_t tskid, uint32_t event, int wait) { task_ *receiver = __task_id_to_ptr(tskid); @@ -365,39 +378,35 @@ uint32_t task_set_event(task_id_t tskid, uint32_t event, int wait) return 0; } - uint32_t task_wait_event(int timeout_us) { return __wait_evt(timeout_us, TASK_ID_IDLE); } - void task_enable_irq(int irq) { CPU_NVIC_EN(irq / 32) = 1 << (irq % 32); } - void task_disable_irq(int irq) { CPU_NVIC_DIS(irq / 32) = 1 << (irq % 32); } - void task_clear_pending_irq(int irq) { CPU_NVIC_UNPEND(irq / 32) = 1 << (irq % 32); } - void task_trigger_irq(int irq) { CPU_NVIC_SWTRIG = irq; } - -/* Initialize IRQs in the NVIC and set their priorities as defined by the - * DECLARE_IRQ statements. */ +/* + * Initialize IRQs in the NVIC and set their priorities as defined by the + * DECLARE_IRQ statements. + */ static void __nvic_init_irqs(void) { /* Get the IRQ priorities section from the linker */ @@ -410,9 +419,11 @@ static void __nvic_init_irqs(void) CPU_NVIC_UNPEND(i) = 0xffffffff; } - /* Re-enable global interrupts in case they're disabled. On a reboot, + /* + * Re-enable global interrupts in case they're disabled. On a reboot, * they're already enabled; if we've jumped here from another image, - * they're not. */ + * they're not. + */ interrupt_enable(); /* Set priorities */ @@ -427,7 +438,6 @@ static void __nvic_init_irqs(void) } } - void mutex_lock(struct mutex *mtx) { uint32_t value; @@ -437,26 +447,24 @@ void mutex_lock(struct mutex *mtx) atomic_or(&mtx->waiters, id); do { - /* try to get the lock (set 1 into the lock field) */ + /* Try to get the lock (set 1 into the lock field) */ __asm__ __volatile__(" ldrex %0, [%1]\n" " teq %0, #0\n" " it eq\n" " strexeq %0, %2, [%1]\n" : "=&r" (value) : "r" (&mtx->lock), "r" (2) : "cc"); - /* "value" is equals to 1 if the store conditional failed, + /* + * "value" is equals to 1 if the store conditional failed, * 2 if somebody else owns the mutex, 0 else. */ - if (value == 2) { - /* contention on the mutex */ - task_wait_event(0); - } + if (value == 2) + task_wait_event(0); /* Contention on the mutex */ } while (value); atomic_clear(&mtx->waiters, id); } - void mutex_unlock(struct mutex *mtx) { uint32_t waiters; @@ -469,10 +477,12 @@ void mutex_unlock(struct mutex *mtx) : "cc"); while (waiters) { task_id_t id = 31 - __builtin_clz(waiters); - /* somebody is waiting on the mutex */ + + /* Somebody is waiting on the mutex */ task_set_event(id, TASK_EVENT_MUTEX, 0); waiters &= ~(1 << id); } + /* Ensure no event is remaining from mutex wake-up */ atomic_clear(&tsk->events, TASK_EVENT_MUTEX); } @@ -501,10 +511,8 @@ void task_print_list(void) } } - #ifdef CONFIG_DEBUG - int command_task_info(int argc, char **argv) { #ifdef CONFIG_TASK_PROFILING @@ -539,7 +547,6 @@ DECLARE_CONSOLE_COMMAND(taskinfo, command_task_info, "Print task info", NULL); - static int command_task_ready(int argc, char **argv) { if (argc < 2) { @@ -557,11 +564,9 @@ DECLARE_CONSOLE_COMMAND(taskready, command_task_ready, "Print/set ready tasks", NULL); - #endif /* CONFIG_DEBUG */ - -int task_pre_init(void) +void task_pre_init(void) { uint32_t *stack_next = (uint32_t *)task_stacks; int i; @@ -614,11 +619,8 @@ int task_pre_init(void) /* Initialize IRQs */ __nvic_init_irqs(); - - return EC_SUCCESS; } - int task_start(void) { #ifdef CONFIG_TASK_PROFILING |