djsundog/circuitpython
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

stmhal/pybthread: Allow interrupts to work during lock/unlock of mutex.

Browse Source 
When locking/unlocking a mutex we only need to protect against a thread
switch, not general interrupts.
This commit is contained in:
Damien George 2017-03-22 12:44:04 +11:00
parent 080210ddc6
commit 96c35d0ac4
1 changed files with 11 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
stmhal/pybthread.c
View File

@ -37,6 +37,11 @@
#define PYB_MUTEX_UNLOCKED ((void*)0)
#define PYB_MUTEX_LOCKED ((void*)1)
// These macros are used when we only need to protect against a thread
// switch; other interrupts are still allowed to proceed.
#define RAISE_IRQ_PRI() raise_irq_pri(IRQ_PRI_PENDSV)
#define RESTORE_IRQ_PRI(state) restore_irq_pri(state)
extern void __fatal_error(const char*);
volatile int pyb_thread_enabled;
@ -176,15 +181,15 @@ void pyb_mutex_init(pyb_mutex_t *m) {
}
int pyb_mutex_lock(pyb_mutex_t *m, int wait) {
uint32_t irq_state = disable_irq();
uint32_t irq_state = RAISE_IRQ_PRI();
if (*m == PYB_MUTEX_UNLOCKED) {
// mutex is available
*m = PYB_MUTEX_LOCKED;
enable_irq(irq_state);
RESTORE_IRQ_PRI(irq_state);
} else {
// mutex is locked
if (!wait) {
enable_irq(irq_state);
RESTORE_IRQ_PRI(irq_state);
return 0; // failed to lock mutex
}
if (*m == PYB_MUTEX_LOCKED) {
@ -202,14 +207,14 @@ int pyb_mutex_lock(pyb_mutex_t *m, int wait) {
pyb_thread_remove_from_runable(pyb_thread_cur);
// thread switch will occur after we enable irqs
SCB->ICSR = SCB_ICSR_PENDSVSET_Msk;
enable_irq(irq_state);
RESTORE_IRQ_PRI(irq_state);
// when we come back we have the mutex
}
return 1; // have mutex
}
void pyb_mutex_unlock(pyb_mutex_t *m) {
uint32_t irq_state = disable_irq();
uint32_t irq_state = RAISE_IRQ_PRI();
if (*m == PYB_MUTEX_LOCKED) {
// no threads are blocked on the mutex
*m = PYB_MUTEX_UNLOCKED;
@ -226,7 +231,7 @@ void pyb_mutex_unlock(pyb_mutex_t *m) {
// put unblocked thread on runable list
pyb_thread_add_to_runable(th);
}
enable_irq(irq_state);
RESTORE_IRQ_PRI(irq_state);
}
#endif // MICROPY_PY_THREAD