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SAMA5/SAMv7: It is necessary to disable pre-emption and interrupts around a loop that copies TX data into the hardware in order to avoid a TX data underrun condition.

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This commit is contained in:
Anthony Merlino 2017-11-13 10:38:23 -06:00 committed by Gregory Nutt
parent 7b676c8a02
commit ea795c8cca
2 changed files with 16 additions and 4 deletions
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10
arch/arm/src/sama5/sam_hsmci.c
View File

@ -2213,6 +2213,7 @@ static int sam_sendsetup(FAR struct sdio_dev_s *dev, FAR const uint8_t *buffer,
unsigned int nwords;
const uint32_t *ptr;
uint32_t sr;
irqstate_t flags;
DEBUGASSERT(priv != NULL && buffer != NULL && buflen > 0);
DEBUGASSERT(((uint32_t)buffer & 3) == 0);
@ -2232,10 +2233,13 @@ static int sam_sendsetup(FAR struct sdio_dev_s *dev, FAR const uint8_t *buffer,
/* Copy each word to the TX FIFO
*
* REVISIT: If TX data underruns occur, then it may be necessary to
* disable pre-emption around this loop.
* It is necessary to disable pre-emption and interrupts around this loop
* in order to avoid a TX data underrun.
*/
sched_lock();
flags = enter_critical_section();
nwords = (buflen + 3) >> 2;
ptr = (const uint32_t *)buffer;
@ -2260,6 +2264,8 @@ static int sam_sendsetup(FAR struct sdio_dev_s *dev, FAR const uint8_t *buffer,
}
}
leave_critical_section(flags);
sched_unlock();
return OK;
}

10
arch/arm/src/samv7/sam_hsmci.c
View File

@ -2200,6 +2200,7 @@ static int sam_sendsetup(FAR struct sdio_dev_s *dev, FAR const uint8_t *buffer,
unsigned int remaining;
const uint32_t *src;
uint32_t sr;
irqstate_t flags;
DEBUGASSERT(priv != NULL && buffer != NULL && buflen > 0);
@ -2229,10 +2230,13 @@ static int sam_sendsetup(FAR struct sdio_dev_s *dev, FAR const uint8_t *buffer,
/* Copy each word to the TX FIFO
*
* REVISIT: If TX data underruns occur, then it may be necessary to
* disable pre-emption around this loop.
* It is necessary to disable pre-emption and interrupts around this loop
* in order to avoid a TX data underrun.
*/
sched_lock();
flags = enter_critical_section();
src = (const uint32_t *)buffer;
remaining = buflen;
@ -2302,6 +2306,8 @@ static int sam_sendsetup(FAR struct sdio_dev_s *dev, FAR const uint8_t *buffer,
}
}
leave_critical_section(flags);
sched_unlock();
return OK;
}