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I had the problem that the transmit FIFO size (= actual elements in FIFO) was slowly increasing over time, and was full after a few hours.

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The reason was that the code hit the line "canerr("ERROR: No available mailbox\n");" in stm32_cansend, so can_xmit thinks it has sent the packet to the hardware, but actually has not. Therefore the transmit interrupt never happens which would call can_txdone, and so the size of the FIFO size does not decrease.

The reason why the code actually hit the mentioned line above, is because stm32can_txready uses a different (incomplete) condition than stm32can_send to determine if the mailbox can be used for sending, and thus can_xmit forwards the packet to stm32can_send. stm32can_txready considered mailboxes OK for sending if the mailbox was empty, but did not consider that mailboxes may not yet be used if the request completed bit is set - stm32can_txinterrupt has to process these mailboxes first.

Note that I have also modified stm32can_txinterrupt - I removed the if condition, because the CAN controller retries to send the packet until it succeeds. Also if the condition would not evaluate to true, can_txdone would not be called and the FIFO size would not decrease also.
This commit is contained in:
Lederhilger Martin 2017-05-16 07:47:18 -06:00 committed by Gregory Nutt
parent 56c8456ff0
commit b8e7d5c455
1 changed files with 71 additions and 31 deletions
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102
arch/arm/src/stm32/stm32_can.c
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@ -1,7 +1,7 @@
/****************************************************************************
* arch/arm/src/stm32/stm32_can.c
*
* Copyright (C) 2011, 2016 Gregory Nutt. All rights reserved.
* Copyright (C) 2011, 2016-2017 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Copyright (C) 2016 Omni Hoverboards Inc. All rights reserved.
@ -74,10 +74,6 @@
#define INAK_TIMEOUT 65535
/* Mailboxes ****************************************************************/
#define CAN_ALL_MAILBOXES (CAN_TSR_TME0 | CAN_TSR_TME1 | CAN_TSR_TME2)
/* Bit timing ***************************************************************/
#define CAN_BIT_QUANTA (CONFIG_CAN_TSEG1 + CONFIG_CAN_TSEG2 + 1)
@ -172,6 +168,12 @@ static int stm32can_bittiming(FAR struct stm32_can_s *priv);
static int stm32can_cellinit(FAR struct stm32_can_s *priv);
static int stm32can_filterinit(FAR struct stm32_can_s *priv);
/* TX mailbox status */
static bool stm32can_txmb0empty(uint32_t tsr_regval);
static bool stm32can_txmb1empty(uint32_t tsr_regval);
static bool stm32can_txmb2empty(uint32_t tsr_regval);
/****************************************************************************
* Private Data
****************************************************************************/
@ -1170,15 +1172,15 @@ static int stm32can_send(FAR struct can_dev_s *dev,
/* Select one empty transmit mailbox */
regval = stm32can_getreg(priv, STM32_CAN_TSR_OFFSET);
if ((regval & CAN_TSR_TME0) != 0 && (regval & CAN_TSR_RQCP0) == 0)
if (stm32can_txmb0empty(regval))
{
txmb = 0;
}
else if ((regval & CAN_TSR_TME1) != 0 && (regval & CAN_TSR_RQCP1) == 0)
else if (stm32can_txmb1empty(regval))
{
txmb = 1;
}
else if ((regval & CAN_TSR_TME2) != 0 && (regval & CAN_TSR_RQCP2) == 0)
else if (stm32can_txmb2empty(regval))
{
txmb = 2;
}
@ -1321,7 +1323,8 @@ static bool stm32can_txready(FAR struct can_dev_s *dev)
regval = stm32can_getreg(priv, STM32_CAN_TSR_OFFSET);
caninfo("CAN%d TSR: %08x\n", priv->port, regval);
return (regval & CAN_ALL_MAILBOXES) != 0;
return stm32can_txmb0empty(regval) || stm32can_txmb1empty(regval) ||
stm32can_txmb2empty(regval);
}
/****************************************************************************
@ -1352,7 +1355,8 @@ static bool stm32can_txempty(FAR struct can_dev_s *dev)
regval = stm32can_getreg(priv, STM32_CAN_TSR_OFFSET);
caninfo("CAN%d TSR: %08x\n", priv->port, regval);
return (regval & CAN_ALL_MAILBOXES) == CAN_ALL_MAILBOXES;
return stm32can_txmb0empty(regval) && stm32can_txmb1empty(regval) &&
stm32can_txmb2empty(regval);
}
/****************************************************************************
@ -1553,14 +1557,9 @@ static int stm32can_txinterrupt(int irq, FAR void *context, FAR void *arg)
stm32can_putreg(priv, STM32_CAN_TSR_OFFSET, CAN_TSR_RQCP0);
/* Check for errors */
/* Tell the upper half that the transfer is finished. */
if ((regval & CAN_TSR_TXOK0) != 0)
{
/* Tell the upper half that the tansfer is finished. */
(void)can_txdone(dev);
}
(void)can_txdone(dev);
}
/* Check for RQCP1: Request completed mailbox 1 */
@ -1573,14 +1572,9 @@ static int stm32can_txinterrupt(int irq, FAR void *context, FAR void *arg)
stm32can_putreg(priv, STM32_CAN_TSR_OFFSET, CAN_TSR_RQCP1);
/* Check for errors */
/* Tell the upper half that the transfer is finished. */
if ((regval & CAN_TSR_TXOK1) != 0)
{
/* Tell the upper half that the tansfer is finished. */
(void)can_txdone(dev);
}
(void)can_txdone(dev);
}
/* Check for RQCP2: Request completed mailbox 2 */
@ -1593,14 +1587,9 @@ static int stm32can_txinterrupt(int irq, FAR void *context, FAR void *arg)
stm32can_putreg(priv, STM32_CAN_TSR_OFFSET, CAN_TSR_RQCP2);
/* Check for errors */
/* Tell the upper half that the transfer is finished. */
if ((regval & CAN_TSR_TXOK2) != 0)
{
/* Tell the upper half that the tansfer is finished. */
(void)can_txdone(dev);
}
(void)can_txdone(dev);
}
return OK;
@ -2111,6 +2100,57 @@ static int stm32can_delstdfilter(FAR struct stm32_can_s *priv, int arg)
return -ENOTTY;
}
/****************************************************************************
* Name: stm32can_txmb0empty
*
* Input Parameter:
* tsr_regval - value of CAN transmit status register
*
* Returned Value:
* Returns true if mailbox 0 is empty and can be used for sending.
*
****************************************************************************/
static bool stm32can_txmb0empty(uint32_t tsr_regval)
{
return (tsr_regval & CAN_TSR_TME0) != 0 &&
(tsr_regval & CAN_TSR_RQCP0) == 0;
}
/****************************************************************************
* Name: stm32can_txmb1empty
*
* Input Parameter:
* tsr_regval - value of CAN transmit status register
*
* Returned Value:
* Returns true if mailbox 1 is empty and can be used for sending.
*
****************************************************************************/
static bool stm32can_txmb1empty(uint32_t tsr_regval)
{
return (tsr_regval & CAN_TSR_TME1) != 0 &&
(tsr_regval & CAN_TSR_RQCP1) == 0;
}
/****************************************************************************
* Name: stm32can_txmb2empty
*
* Input Parameter:
* tsr_regval - value of CAN transmit status register
*
* Returned Value:
* Returns true if mailbox 2 is empty and can be used for sending.
*
****************************************************************************/
static bool stm32can_txmb2empty(uint32_t tsr_regval)
{
return (tsr_regval & CAN_TSR_TME2) != 0 &&
(tsr_regval & CAN_TSR_RQCP2) == 0;
}
/****************************************************************************
* Public Functions
****************************************************************************/