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msm: smd: provide atomic channel writes

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Some smd clients may write from multiple threads, in which case it's
not safe to call smd_write without holding a lock.  smd_write_atomic()
provides the same functionality as smd_write() but obtains the smd
lock first.

Signed-off-by: Brian Swetland <swetland@google.com>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>
This commit is contained in:
Brian Swetland 2009-12-07 15:28:08 -08:00 committed by Daniel Walker
parent 1207babdcd
commit 636eb9cbae
2 changed files with 11 additions and 0 deletions
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1
arch/arm/mach-msm/include/mach/msm_smd.h
View file

@ -38,6 +38,7 @@ int smd_read(smd_channel_t *ch, void *data, int len);
** it will return the requested length written or an error.
*/
int smd_write(smd_channel_t *ch, const void *data, int len);
int smd_write_atomic(smd_channel_t *ch, const void *data, int len);
int smd_write_avail(smd_channel_t *ch);
int smd_read_avail(smd_channel_t *ch);

10
arch/arm/mach-msm/smd.c
View file

@ -804,6 +804,16 @@ int smd_write(smd_channel_t *ch, const void *data, int len)
return ch->write(ch, data, len);
}
int smd_write_atomic(smd_channel_t *ch, const void *data, int len)
{
unsigned long flags;
int res;
spin_lock_irqsave(&smd_lock, flags);
res = ch->write(ch, data, len);
spin_unlock_irqrestore(&smd_lock, flags);
return res;
}
int smd_read_avail(smd_channel_t *ch)
{
return ch->read_avail(ch);