diff options
Diffstat (limited to 'core/cortex-m0/task.c')
| -rw-r--r-- | core/cortex-m0/task.c | 691 |
1 files changed, 0 insertions, 691 deletions
diff --git a/core/cortex-m0/task.c b/core/cortex-m0/task.c deleted file mode 100644 index ba40b667b6..0000000000 --- a/core/cortex-m0/task.c +++ /dev/null @@ -1,691 +0,0 @@ -/* Copyright 2014 The Chromium OS Authors. All rights reserved. - * Use of this source code is governed by a BSD-style license that can be - * found in the LICENSE file. - */ - -/* Task scheduling / events module for Chrome EC operating system */ - -#include "atomic.h" -#include "common.h" -#include "console.h" -#include "cpu.h" -#include "link_defs.h" -#include "panic.h" -#include "task.h" -#include "timer.h" -#include "util.h" - -typedef union { - struct { - /* - * Note that sp must be the first element in the task struct - * for __switchto() to work. - */ - uint32_t sp; /* Saved stack pointer for context switch */ - uint32_t events; /* Bitmaps of received events */ - uint64_t runtime; /* Time spent in task */ - uint32_t *stack; /* Start of stack */ - }; -} task_; - -/* Value to store in unused stack */ -#define STACK_UNUSED_VALUE 0xdeadd00d - -/* declare task routine prototypes */ -#define TASK(n, r, d, s) void r(void *); -void __idle(void); -CONFIG_TASK_LIST -CONFIG_TEST_TASK_LIST -CONFIG_CTS_TASK_LIST -#undef TASK - -/* Task names for easier debugging */ -#define TASK(n, r, d, s) #n, -static const char * const task_names[] = { - "<< idle >>", - CONFIG_TASK_LIST - CONFIG_TEST_TASK_LIST - CONFIG_CTS_TASK_LIST -}; -#undef TASK - -#ifdef CONFIG_TASK_PROFILING -static uint64_t task_start_time; /* Time task scheduling started */ -/* - * We only keep 32-bit values for exception start/end time, to avoid - * accounting errors when we service interrupt when the timer wraps around. - */ -static uint32_t exc_start_time; /* Time of task->exception transition */ -static uint32_t exc_end_time; /* Time of exception->task transition */ -static uint64_t exc_total_time; /* Total time in exceptions */ -static uint32_t svc_calls; /* Number of service calls */ -static uint32_t task_switches; /* Number of times active task changed */ -static uint32_t irq_dist[CONFIG_IRQ_COUNT]; /* Distribution of IRQ calls */ -#endif - -extern int __task_start(int *task_stack_ready); - -#ifndef CONFIG_LOW_POWER_IDLE -/* Idle task. Executed when no tasks are ready to be scheduled. */ -void __idle(void) -{ - while (1) { - /* - * 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(); - cprints(CC_TASK, "Task %d (%s) exited!", i, task_names[i]); - /* Exited tasks simply sleep forever */ - while (1) - task_wait_event(-1); -} - -/* Startup parameters for all tasks. */ -#define TASK(n, r, d, s) { \ - .r0 = (uint32_t)d, \ - .pc = (uint32_t)r, \ - .stack_size = s, \ -}, -static const struct { - uint32_t r0; - uint32_t pc; - uint16_t stack_size; -} tasks_init[] = { - TASK(IDLE, __idle, 0, IDLE_TASK_STACK_SIZE) - CONFIG_TASK_LIST - CONFIG_TEST_TASK_LIST - CONFIG_CTS_TASK_LIST -}; -#undef TASK - -/* Contexts for all tasks */ -static task_ tasks[TASK_ID_COUNT]; -/* Validity checks about static task invariants */ -BUILD_ASSERT(TASK_ID_COUNT <= sizeof(unsigned) * 8); -BUILD_ASSERT(TASK_ID_COUNT < (1 << (sizeof(task_id_t) * 8))); - - -/* Stacks for all tasks */ -#define TASK(n, r, d, s) + s -uint8_t task_stacks[0 - TASK(IDLE, __idle, 0, IDLE_TASK_STACK_SIZE) - CONFIG_TASK_LIST - CONFIG_TEST_TASK_LIST - CONFIG_CTS_TASK_LIST -] __aligned(8); - -#undef TASK - -/* Reserve space to discard context on first context switch. */ -uint32_t scratchpad[17]; - -task_ *current_task = (task_ *)scratchpad; - -/* - * Bitmap of all tasks ready to be run. - * - * Start off with only the hooks task marked as ready such that all the modules - * can do their init within a task switching context. The hooks task will then - * make a call to enable all tasks. - */ -static uint32_t tasks_ready = BIT(TASK_ID_HOOKS); -/* - * Initially allow only the HOOKS and IDLE task to run, regardless of ready - * status, in order for HOOK_INIT to complete before other tasks. - * task_enable_all_tasks() will open the flood gates. - */ -static uint32_t tasks_enabled = BIT(TASK_ID_HOOKS) | BIT(TASK_ID_IDLE); - -static int start_called; /* Has task swapping started */ - -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 is_interrupt_enabled(void) -{ - int primask; - - /* Interrupts are enabled when PRIMASK bit is 0 */ - asm("mrs %0, primask":"=r"(primask)); - - return !(primask & 0x1); -} - -inline int in_interrupt_context(void) -{ - int ret; - asm("mrs %0, ipsr\n" /* read exception number */ - "lsl %0, #23\n" : "=r"(ret)); /* exception bits are the 9 LSB */ - return ret; -} - -static 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 */ -} - -task_id_t task_get_current(void) -{ -#ifdef CONFIG_DEBUG_BRINGUP - /* If we haven't done a context switch then our task ID isn't valid */ - ASSERT(current_task != (task_ *)scratchpad); -#endif - return current_task - tasks; -} - -uint32_t *task_get_event_bitmap(task_id_t tskid) -{ - task_ *tsk = __task_id_to_ptr(tskid); - return &tsk->events; -} - -int task_start_called(void) -{ - return start_called; -} - -/** - * Scheduling system call - */ -task_ __attribute__((noinline)) *__svc_handler(int desched, task_id_t resched) -{ - task_ *current, *next; -#ifdef CONFIG_TASK_PROFILING - int exc = get_interrupt_context(); - uint32_t t; -#endif - - /* Priority is already at 0 we cannot be interrupted */ - -#ifdef CONFIG_TASK_PROFILING - /* - * SVCall isn't triggered via DECLARE_IRQ(), so it needs to track its - * start time explicitly. - */ - if (exc == 0xb) { - t = get_time().le.lo; - current_task->runtime += (t - exc_end_time); - exc_end_time = t; - svc_calls++; - } -#endif - - current = current_task; - -#ifdef CONFIG_DEBUG_STACK_OVERFLOW - if (*current->stack != STACK_UNUSED_VALUE) { - panic_printf("\n\nStack overflow in %s task!\n", - task_names[current - tasks]); -#ifdef CONFIG_SOFTWARE_PANIC - software_panic(PANIC_SW_STACK_OVERFLOW, current - tasks); -#endif - } -#endif - - if (desched && !current->events) { - /* - * Remove our own ready bit (current - tasks is same as - * task_get_current()) - */ - tasks_ready &= ~(1 << (current - tasks)); - } - tasks_ready |= 1 << resched; - - ASSERT(tasks_ready & tasks_enabled); - next = __task_id_to_ptr(__fls(tasks_ready & tasks_enabled)); - -#ifdef CONFIG_TASK_PROFILING - /* Track additional time in re-sched exception context */ - t = get_time().le.lo; - exc_total_time += (t - exc_end_time); - - exc_end_time = t; -#endif - - /* Switch to new task */ -#ifdef CONFIG_TASK_PROFILING - if (next != current) - task_switches++; -#endif - current_task = next; - return current; -} - -void __schedule(int desched, int resched) -{ - register int p0 asm("r0") = desched; - register int p1 asm("r1") = resched; - - asm("svc 0" : : "r"(p0), "r"(p1)); -} - -#ifdef CONFIG_TASK_PROFILING -void task_start_irq_handler(void *excep_return) -{ - /* - * Get time before checking depth, in case this handler is - * pre-empted. - */ - uint32_t t = get_time().le.lo; - int irq = get_interrupt_context() - 16; - - /* - * 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 the tasks are ready and we are not called from another - * exception (as the time accouting is done in the outer irq). - */ - if (!start_called || ((uint32_t)excep_return & 0xf) == 1) - return; - - exc_start_time = t; - /* - * Bill the current task for time between the end of the last interrupt - * and the start of this one. - */ - current_task->runtime += (exc_start_time - exc_end_time); -} - -void task_end_irq_handler(void *excep_return) -{ - uint32_t t = get_time().le.lo; - /* - * Continue iff the tasks are ready and we are not called from another - * exception (as the time accouting is done in the outer irq). - */ - if (!start_called || ((uint32_t)excep_return & 0xf) == 1) - return; - - /* Track time in interrupts */ - exc_total_time += (t - exc_start_time); - exc_end_time = t; -} -#endif - -static uint32_t __wait_evt(int timeout_us, task_id_t resched) -{ - task_ *tsk = current_task; - task_id_t me = tsk - tasks; - uint32_t evt; - int ret __attribute__((unused)); - - /* - * Scheduling task when interrupts are disabled will result in Forced - * Hard Fault because disabling interrupt using 'cpsid i' also disables - * SVCall handler (because it has configurable priority) - */ - ASSERT(is_interrupt_enabled()); - ASSERT(!in_interrupt_context()); - - if (timeout_us > 0) { - timestamp_t deadline = get_time(); - deadline.val += timeout_us; - ret = timer_arm(deadline, me); - ASSERT(ret == EC_SUCCESS); - } - while (!(evt = atomic_clear(&tsk->events))) { - /* - * We need to ensure that the execution priority is actually - * decreased after the "cpsie i" in the atomic operation above - * else the "svc" in the __schedule call below will trigger - * a HardFault. Use a barrier to force it at that point. - */ - asm volatile("isb"); - /* Remove ourself and get the next task in the scheduler */ - __schedule(1, resched); - resched = TASK_ID_IDLE; - } - if (timeout_us > 0) { - timer_cancel(me); - /* Ensure timer event is clear, we no longer care about it */ - atomic_clear_bits(&tsk->events, TASK_EVENT_TIMER); - } - return evt; -} - -uint32_t task_set_event(task_id_t tskid, uint32_t event) -{ - task_ *receiver = __task_id_to_ptr(tskid); - ASSERT(receiver); - - /* Set the event bit in the receiver message bitmap */ - atomic_or(&receiver->events, event); - - /* Re-schedule if priorities have changed */ - if (in_interrupt_context() || !is_interrupt_enabled()) { - /* The receiver might run again */ - atomic_or(&tasks_ready, 1 << tskid); - if (start_called) { - /* - * Trigger the scheduler when there's - * no other irqs happening. - */ - CPU_SCB_ICSR = BIT(28); - } - } else { - /* - * We need to ensure that the execution priority is - * actually decreased after the "cpsie i" in the atomic - * operation above else the "svc" in the __schedule - * call below will trigger a HardFault. - * Use a barrier to force it at that point. - */ - asm volatile("isb"); - __schedule(0, tskid); - } - - return 0; -} - -uint32_t task_wait_event(int timeout_us) -{ - return __wait_evt(timeout_us, TASK_ID_IDLE); -} - -uint32_t task_wait_event_mask(uint32_t event_mask, int timeout_us) -{ - uint64_t deadline = get_time().val + timeout_us; - uint32_t events = 0; - int time_remaining_us = timeout_us; - - /* Add the timer event to the mask so we can indicate a timeout */ - event_mask |= TASK_EVENT_TIMER; - - while (!(events & event_mask)) { - /* Collect events to re-post later */ - events |= __wait_evt(time_remaining_us, TASK_ID_IDLE); - - time_remaining_us = deadline - get_time().val; - if (timeout_us > 0 && time_remaining_us <= 0) { - /* Ensure we return a TIMER event if we timeout */ - events |= TASK_EVENT_TIMER; - break; - } - } - - /* Re-post any other events collected */ - if (events & ~event_mask) - atomic_or(¤t_task->events, events & ~event_mask); - - return events & event_mask; -} - -void task_enable_all_tasks(void) -{ - /* Mark all tasks as ready and able to run. */ - tasks_ready = tasks_enabled = BIT(TASK_ID_COUNT) - 1; - /* Reschedule the highest priority task. */ - if (is_interrupt_enabled()) - __schedule(0, 0); -} - -void task_enable_task(task_id_t tskid) -{ - atomic_or(&tasks_enabled, BIT(tskid)); -} - -void task_disable_task(task_id_t tskid) -{ - atomic_clear_bits(&tasks_enabled, BIT(tskid)); - - if (!in_interrupt_context() && is_interrupt_enabled() && - tskid == task_get_current()) - __schedule(0, 0); -} - -void task_enable_irq(int irq) -{ - CPU_NVIC_EN(0) = 1 << irq; -} - -void task_disable_irq(int irq) -{ - CPU_NVIC_DIS(0) = 1 << irq; -} - -void task_clear_pending_irq(int irq) -{ - CPU_NVIC_UNPEND(0) = 1 << irq; -} - -void task_trigger_irq(int irq) -{ - CPU_NVIC_ISPR(0) = 1 << irq; -} - -/* - * 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 */ - int exc_calls = __irqprio_end - __irqprio; - int i; - - /* Mask and clear all pending interrupts */ - CPU_NVIC_DIS(0) = 0xffffffff; - CPU_NVIC_UNPEND(0) = 0xffffffff; - - /* - * 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. - */ - interrupt_enable(); - - /* Set priorities */ - for (i = 0; i < exc_calls; i++) { - cpu_set_interrupt_priority(__irqprio[i].irq, - __irqprio[i].priority); - } -} - -void mutex_lock(struct mutex *mtx) -{ - uint32_t id = 1 << task_get_current(); - - ASSERT(id != TASK_ID_INVALID); - atomic_or(&mtx->waiters, id); - - while (1) { - /* Try to get the lock (set 2 into the lock field) */ - __asm__ __volatile__("cpsid i"); - if (mtx->lock == 0) - break; - __asm__ __volatile__("cpsie i"); - /* Contention on the mutex */ - task_wait_event_mask(TASK_EVENT_MUTEX, 0); - } - mtx->lock = 2; - __asm__ __volatile__("cpsie i"); - - atomic_clear_bits(&mtx->waiters, id); -} - -void mutex_unlock(struct mutex *mtx) -{ - uint32_t waiters; - task_ *tsk = current_task; - - /* - * Add a critical section to keep the unlock and the snapshotting of - * waiters atomic in case a task switching occurs between them. - */ - interrupt_disable(); - waiters = mtx->waiters; - mtx->lock = 0; - interrupt_enable(); - - while (waiters) { - task_id_t id = __fls(waiters); - waiters &= ~BIT(id); - - /* Somebody is waiting on the mutex */ - task_set_event(id, TASK_EVENT_MUTEX); - } - - /* Ensure no event is remaining from mutex wake-up */ - atomic_clear_bits(&tsk->events, TASK_EVENT_MUTEX); -} - -void task_print_list(void) -{ - int i; - - ccputs("Task Ready Name Events Time (s) StkUsed\n"); - - for (i = 0; i < TASK_ID_COUNT; i++) { - char is_ready = (tasks_ready & (1<<i)) ? 'R' : ' '; - uint32_t *sp; - - int stackused = tasks_init[i].stack_size; - - for (sp = tasks[i].stack; - sp < (uint32_t *)tasks[i].sp && *sp == STACK_UNUSED_VALUE; - sp++) - stackused -= sizeof(uint32_t); - - ccprintf("%4d %c %-16s %08x %11.6lld %3d/%3d\n", i, is_ready, - task_names[i], tasks[i].events, tasks[i].runtime, - stackused, tasks_init[i].stack_size); - cflush(); - } -} - -int command_task_info(int argc, char **argv) -{ -#ifdef CONFIG_TASK_PROFILING - int total = 0; - int i; -#endif - - task_print_list(); - -#ifdef CONFIG_TASK_PROFILING - ccputs("IRQ counts by type:\n"); - cflush(); - for (i = 0; i < ARRAY_SIZE(irq_dist); i++) { - if (irq_dist[i]) { - ccprintf("%4d %8d\n", i, irq_dist[i]); - total += irq_dist[i]; - } - } - ccprintf("Service calls: %11d\n", svc_calls); - ccprintf("Total exceptions: %11d\n", total + svc_calls); - ccprintf("Task switches: %11d\n", task_switches); - ccprintf("Task switching started: %11.6lld s\n", task_start_time); - ccprintf("Time in tasks: %11.6lld s\n", - get_time().val - task_start_time); - ccprintf("Time in exceptions: %11.6lld s\n", exc_total_time); -#endif - - return EC_SUCCESS; -} -DECLARE_CONSOLE_COMMAND(taskinfo, command_task_info, - NULL, - "Print task info"); - -#ifdef CONFIG_CMD_TASKREADY -static int command_task_ready(int argc, char **argv) -{ - if (argc < 2) { - ccprintf("tasks_ready: 0x%08x\n", tasks_ready); - } else { - tasks_ready = strtoi(argv[1], NULL, 16); - ccprintf("Setting tasks_ready to 0x%08x\n", tasks_ready); - __schedule(0, 0); - } - - return EC_SUCCESS; -} -DECLARE_CONSOLE_COMMAND(taskready, command_task_ready, - "[setmask]", - "Print/set ready tasks"); -#endif - -void task_pre_init(void) -{ - uint32_t *stack_next = (uint32_t *)task_stacks; - int i; - - /* Fill the task memory with initial values */ - for (i = 0; i < TASK_ID_COUNT; i++) { - uint32_t *sp; - /* Stack size in words */ - uint32_t ssize = tasks_init[i].stack_size / 4; - - tasks[i].stack = stack_next; - - /* - * Update stack used by first frame: 8 words for the normal - * stack, plus 8 for R4-R11. With FP enabled, we need another - * 18 words for S0-S15 and FPCSR and to align to 64-bit. - */ - sp = stack_next + ssize - 16; - tasks[i].sp = (uint32_t)sp; - - /* Initial context on stack (see __switchto()) */ - sp[8] = tasks_init[i].r0; /* r0 */ - sp[13] = (uint32_t)task_exit_trap; /* lr */ - sp[14] = tasks_init[i].pc; /* pc */ - sp[15] = 0x01000000; /* psr */ - - /* Fill unused stack; also used to detect stack overflow. */ - for (sp = stack_next; sp < (uint32_t *)tasks[i].sp; sp++) - *sp = STACK_UNUSED_VALUE; - - stack_next += ssize; - } - - /* - * Fill in guard value in scratchpad to prevent stack overflow - * detection failure on the first context switch. This works because - * the first word in the scratchpad is where the switcher will store - * sp, so it's ok to blow away. - */ - ((task_ *)scratchpad)->stack = (uint32_t *)scratchpad; - *(uint32_t *)scratchpad = STACK_UNUSED_VALUE; - - /* Initialize IRQs */ - __nvic_init_irqs(); -} - -int task_start(void) -{ -#ifdef CONFIG_TASK_PROFILING - timestamp_t t = get_time(); - - task_start_time = t.val; - exc_end_time = t.le.lo; -#endif - - return __task_start(&start_called); -} |