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drivers/usbdev/cdcacm.c: Fix confusion between flow control being enabled and being active. Different things

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This commit is contained in:
Gregory Nutt 2017-09-27 06:41:32 -06:00
parent 7ceedd2b52
commit 8ad1e72536
1 changed files with 62 additions and 36 deletions
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98
drivers/usbdev/cdcacm.c
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@ -114,6 +114,7 @@ struct cdcacm_dev_s
#ifdef CONFIG_CDCACM_IFLOWCONTROL #ifdef CONFIG_CDCACM_IFLOWCONTROL
uint8_t serialstate; /* State of the DSR/DCD */ uint8_t serialstate; /* State of the DSR/DCD */
bool iflow; /* True: input flow control is enabled */ bool iflow; /* True: input flow control is enabled */
bool iactive; /* True: input flow control is active */
bool upper; /* True: RX buffer is (nearly) full */ bool upper; /* True: RX buffer is (nearly) full */
#endif #endif
bool rxenabled; /* true: UART RX "interrupts" enabled */ bool rxenabled; /* true: UART RX "interrupts" enabled */
@ -481,7 +482,7 @@ static int cdcacm_recvpacket(FAR struct cdcacm_dev_s *priv,
DEBUGASSERT(priv != NULL && rdcontainer != NULL); DEBUGASSERT(priv != NULL && rdcontainer != NULL);
#ifdef CONFIG_CDCACM_IFLOWCONTROL #ifdef CONFIG_CDCACM_IFLOWCONTROL
DEBUGASSERT(priv->rxenabled && !priv->iflow); DEBUGASSERT(priv->rxenabled && !priv->iactive);
#else #else
DEBUGASSERT(priv->rxenabled); DEBUGASSERT(priv->rxenabled);
#endif #endif
@ -619,9 +620,9 @@ static int cdcacm_release_rxpending(FAR struct cdcacm_dev_s *priv)
irqstate_t flags; irqstate_t flags;
int ret = -EBUSY; int ret = -EBUSY;
/* Note that the priv->rxpending queue, priv->rxenabled, priv->iflow may /* Note that the priv->rxpending queue, priv->rxenabled, priv->iactive
* be modified by interrupt level processing and, hence, interrupts must * may be modified by interrupt level processing and, hence, interrupts
* be disabled throughout the following. * must be disabled throughout the following.
*/ */
flags = enter_critical_section(); flags = enter_critical_section();
@ -637,7 +638,7 @@ static int cdcacm_release_rxpending(FAR struct cdcacm_dev_s *priv)
*/ */
#ifdef CONFIG_CDCACM_IFLOWCONTROL #ifdef CONFIG_CDCACM_IFLOWCONTROL
if (priv->rxenabled && !priv->iflow) if (priv->rxenabled && !priv->iactive)
#else #else
if (priv->rxenabled) if (priv->rxenabled)
#endif #endif
@ -2335,7 +2336,7 @@ static int cdcuart_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
if (!iflow) if (!iflow)
{ {
irqstate_t flags; irqstate_t flags = enter_critical_section();
/* Flow control has been disabled. We need to make sure /* Flow control has been disabled. We need to make sure
* that DSR is set unconditionally. * that DSR is set unconditionally.
@ -2357,26 +2358,38 @@ static int cdcuart_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
/* Save the new flow control setting. */ /* Save the new flow control setting. */
priv->iflow = false; priv->iflow = false;
priv->iactive = false;
leave_critical_section(flags); leave_critical_section(flags);
} }
/* Flow control has been enabled. If the RX buffer is already /* Flow control has been enabled. */
* (nearly) full, the we need to make sure the DSR is clear.
*
* NOTE: Here we assume that DSR is set so we don't check its
* current value nor to we handle the case where we would set
* DSR because the RX buffer is (nearly) empty!
*/
else if (priv->upper) else
{ {
/* Save the new flow control setting. */ /* Save the new flow control setting. */
priv->iflow = true; priv->iflow = true;
priv->serialstate &= ~CDCACM_UART_DSR; priv->iactive = false;
priv->serialstate |= CDCACM_UART_DCD;
ret = cdcacm_serialstate(priv); /* If the RX buffer is already (nearly) full, the we need to
* make sure the DSR is clear.
*
* NOTE: Here we assume that DSR is set so we don't check its
* current value nor to we handle the case where we would set
* DSR because the RX buffer is (nearly) empty!
*/
if (priv->upper)
{
priv->serialstate &= ~CDCACM_UART_DSR;
priv->serialstate |= CDCACM_UART_DCD;
ret = cdcacm_serialstate(priv);
/* Input flow control is now active */
priv->iactive = true;
}
} }
/* RX "interrupts are no longer disabled */ /* RX "interrupts are no longer disabled */
@ -2529,7 +2542,7 @@ static void cdcuart_rxint(FAR struct uart_dev_s *dev, bool enable)
* *
* We also need to check if input control flow is in effect. If so, * We also need to check if input control flow is in effect. If so,
* then we should not call uart_datareceived() until both * then we should not call uart_datareceived() until both
* priv->rxenabled is true and priv->iflow are false. * priv->rxenabled is true and priv->iactive are false.
*/ */
if (!priv->rxenabled) if (!priv->rxenabled)
@ -2629,15 +2642,17 @@ static bool cdcuart_rxflowcontrol(FAR struct uart_dev_s *dev,
priv->serialstate &= ~CDCACM_UART_DSR; priv->serialstate &= ~CDCACM_UART_DSR;
priv->serialstate |= CDCACM_UART_DCD; priv->serialstate |= CDCACM_UART_DCD;
/* And send the SerialState message */ /* And send the SerialState message.
* REVISIT: Error return case. Would an error mean DSR is not
* set?
*/
ret = cdcacm_serialstate(priv); (void)cdcacm_serialstate(priv);
if (ret >= 0)
{
priv->iflow = true;
return true;
}
} }
/* Flow control is active */
priv->iactive = true;
} }
/* Lower watermark crossing. Don't do anything unless this results in /* Lower watermark crossing. Don't do anything unless this results in
@ -2650,14 +2665,19 @@ static bool cdcuart_rxflowcontrol(FAR struct uart_dev_s *dev,
priv->serialstate |= (CDCACM_UART_DSR | CDCACM_UART_DCD); priv->serialstate |= (CDCACM_UART_DSR | CDCACM_UART_DCD);
/* And send the SerialState message */ /* And send the SerialState message.
* REVISIT: Error return case. Would an error mean DSR is still
* clear?
*/
ret = cdcacm_serialstate(priv); ret = cdcacm_serialstate(priv);
if (ret >= 0) if (ret >= 0)
{ {
/* Needed by cdcacm_release_rxpending() */ /* Flow control is not active (Needed before calling
* cdcacm_release_rxpending())
*/
priv->iflow = false; priv->iactive = false;
/* During the time that flow control ws disabled, /* During the time that flow control ws disabled,
* incoming packets were queued in priv->rxpending. We * incoming packets were queued in priv->rxpending. We
@ -2678,20 +2698,26 @@ static bool cdcuart_rxflowcontrol(FAR struct uart_dev_s *dev,
if ((priv->serialstate & CDCACM_UART_DSR) == 0) if ((priv->serialstate & CDCACM_UART_DSR) == 0)
{ {
/* Set DSR and DCD */ /* Set DSR and DCD */
priv->serialstate |= (CDCACM_UART_DSR | CDCACM_UART_DCD); priv->serialstate |= (CDCACM_UART_DSR | CDCACM_UART_DCD);
/* And send the SerialState message */ /* And send the SerialState message
* REVISIT: Error return case. Would an error mean DSR is still
* not set?
*/
(void)cdcacm_serialstate(priv); (void)cdcacm_serialstate(priv);
/* Flow control is not active */
priv->iactive = false;
} }
} }
/* Return true of DSR is not set */ /* Return true flow control is active */
priv->iflow = ((priv->serialstate & CDCACM_UART_DSR) == 0); return priv->iactive;
return priv->iflow;
#else #else
return false; return false;