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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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80
drivers/usbdev/cdcacm.c
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@ -114,6 +114,7 @@ struct cdcacm_dev_s
#ifdef CONFIG_CDCACM_IFLOWCONTROL
uint8_t serialstate; /* State of the DSR/DCD */
bool iflow; /* True: input flow control is enabled */
bool iactive; /* True: input flow control is active */
bool upper; /* True: RX buffer is (nearly) full */
#endif
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);
#ifdef CONFIG_CDCACM_IFLOWCONTROL
DEBUGASSERT(priv->rxenabled && !priv->iflow);
DEBUGASSERT(priv->rxenabled && !priv->iactive);
#else
DEBUGASSERT(priv->rxenabled);
#endif
@ -619,9 +620,9 @@ static int cdcacm_release_rxpending(FAR struct cdcacm_dev_s *priv)
irqstate_t flags;
int ret = -EBUSY;
/* Note that the priv->rxpending queue, priv->rxenabled, priv->iflow may
* be modified by interrupt level processing and, hence, interrupts must
* be disabled throughout the following.
/* Note that the priv->rxpending queue, priv->rxenabled, priv->iactive
* may be modified by interrupt level processing and, hence, interrupts
* must be disabled throughout the following.
*/
flags = enter_critical_section();
@ -637,7 +638,7 @@ static int cdcacm_release_rxpending(FAR struct cdcacm_dev_s *priv)
*/
#ifdef CONFIG_CDCACM_IFLOWCONTROL
if (priv->rxenabled && !priv->iflow)
if (priv->rxenabled && !priv->iactive)
#else
if (priv->rxenabled)
#endif
@ -2335,7 +2336,7 @@ static int cdcuart_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
if (!iflow)
{
irqstate_t flags;
irqstate_t flags = enter_critical_section();
/* Flow control has been disabled. We need to make sure
* that DSR is set unconditionally.
@ -2358,25 +2359,37 @@ static int cdcuart_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
/* Save the new flow control setting. */
priv->iflow = false;
priv->iactive = false;
leave_critical_section(flags);
}
/* Flow control has been enabled. If the RX buffer is already
* (nearly) full, the we need to make sure the DSR is clear.
/* Flow control has been enabled. */
else
{
/* Save the new flow control setting. */
priv->iflow = true;
priv->iactive = false;
/* 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!
*/
else if (priv->upper)
if (priv->upper)
{
/* Save the new flow control setting. */
priv->iflow = true;
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 */
@ -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,
* 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)
@ -2629,15 +2642,17 @@ static bool cdcuart_rxflowcontrol(FAR struct uart_dev_s *dev,
priv->serialstate &= ~CDCACM_UART_DSR;
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);
if (ret >= 0)
{
priv->iflow = true;
return true;
}
(void)cdcacm_serialstate(priv);
}
/* Flow control is active */
priv->iactive = true;
}
/* 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);
/* 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);
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,
* incoming packets were queued in priv->rxpending. We
@ -2682,16 +2702,22 @@ static bool cdcuart_rxflowcontrol(FAR struct uart_dev_s *dev,
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);
/* 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->iflow;
return priv->iactive;
#else
return false;