len0rd/rockbox
1
0
Fork 1
mirror of https://github.com/Rockbox/rockbox.git synced 2025-10-13 18:17:39 -04:00
Code Issues Projects Releases Packages Wiki Activity Actions

Put an end to priority inversion in the ata driver. Gave up trying to have fully atomic dual use mutexes so just replaced the ata driver locking with spins. Maybe I'll have better luck later. Things should run smoothly with database updates and such happening in the background.

Browse source 
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@12688 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Michael Sevakis 2007-03-09 08:03:18 +00:00
parent f4b83e6859
commit dee43ece20
6 changed files with 135 additions and 69 deletions
Download patch file Download diff file Expand all files Collapse all files

81
firmware/kernel.c
View file

@ -656,48 +656,73 @@ void mutex_init(struct mutex *m)
m->thread = NULL;
}
#ifdef CPU_PP
/* PortalPlayer chips have 2 cores, therefore need atomic mutexes */
static inline bool test_and_set(bool *x, bool v)
{
asm volatile (
"swpb %0, %0, [%1]\n"
: "+r"(v)
: "r"(x)
);
return v;
}
void mutex_lock(struct mutex *m)
{
if (test_and_set(&m->locked,true))
{
/* Wait until the lock is open... */
block_thread(&m->thread);
}
}
/* PortalPlayer chips have 2 cores, therefore need atomic mutexes
* Just use it for ARM, Coldfire and whatever else well...why not?
*/
/* Macros generate better code than an inline function is this case */
#if defined (CPU_PP) || defined (CPU_ARM)
#define test_and_set(x_, v_) \
({ \
uint32_t old; \
asm volatile ( \
"swpb %[old], %[v], [%[x]] \r\n" \
: [old]"=r"(old) \
: [v]"r"((uint32_t)v_), [x]"r"((uint32_t *)x_) \
); \
old; \
})
#elif defined (CPU_COLDFIRE)
#define test_and_set(x_, v_) \
({ \
uint8_t old; \
asm volatile ( \
"bset.l %[v], (%[x]) \r\n" \
"sne.b %[old] \r\n" \
: [old]"=d,d"(old) \
: [v]"i,d"((uint32_t)v_), [x]"a,a"((uint32_t *)x_) \
); \
old; \
})
#else
/* default for no asm version */
#define test_and_set(x_, v_) \
({ \
uint32_t old = *(uint32_t *)x_; \
*(uint32_t *)x_ = v_; \
old; \
})
#endif
void mutex_lock(struct mutex *m)
{
if (m->locked)
if (test_and_set(&m->locked, 1))
{
/* Wait until the lock is open... */
block_thread(&m->thread);
}
/* ...and lock it */
m->locked = true;
}
#endif
void mutex_unlock(struct mutex *m)
{
if (m->thread == NULL)
m->locked = false;
m->locked = 0;
else
wakeup_thread(&m->thread);
}
#endif
void spinlock_lock(struct mutex *m)
{
while (test_and_set(&m->locked, 1))
{
/* wait until the lock is open... */
switch_thread(true, NULL);
}
}
void spinlock_unlock(struct mutex *m)
{
m->locked = 0;
}
#endif /* ndef SIMULATOR */