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Commit d5a7b406 authored by Marc Kleine-Budde's avatar Marc Kleine-Budde
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can: flexcan: flexcan_chip_start: fix regression, mark one MB for TX and abort pending TX 



In patch

    0d1862ea can: flexcan: fix flexcan_chip_start() on imx6

the loop in flexcan_chip_start() that iterates over all mailboxes after the
soft reset of the CAN core was removed. This loop put all mailboxes (even the
ones marked as reserved 1...7) into EMPTY/INACTIVE mode. On mailboxes 8...63,
this aborts any pending TX messages.

After a cold boot there is random garbage in the mailboxes, which leads to
spontaneous transmit of CAN frames during first activation. Further if the
interface was disabled with a pending message (usually due to an error
condition on the CAN bus), this message is retransmitted after enabling the
interface again.

This patch fixes the regression by:
1) Limiting the maximum number of used mailboxes to 8, 0...7 are used by the RX
FIFO, 8 is used by TX.
2) Marking the TX mailbox as EMPTY/INACTIVE, so that any pending TX of that
mailbox is aborted.

Cc: linux-stable <stable@vger.kernel.org>
Cc: Lothar Waßmann <LW@KARO-electronics.de>
Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent 87b0a0b5

drivers/net/can/flexcan.c

+8 −2
Original line number Diff line number Diff line
@@ -62,7 +62,7 @@ 
#define FLEXCAN_MCR_BCC			BIT(16)

#define FLEXCAN_MCR_LPRIO_EN		BIT(13)

#define FLEXCAN_MCR_AEN			BIT(12)

#define FLEXCAN_MCR_MAXMB(x)		((x) & 0xf)

#define FLEXCAN_MCR_MAXMB(x)		((x) & 0x1f)

#define FLEXCAN_MCR_IDAM_A		(0 << 8)

#define FLEXCAN_MCR_IDAM_B		(1 << 8)

#define FLEXCAN_MCR_IDAM_C		(2 << 8)
@@ -735,9 +735,11 @@ static int flexcan_chip_start(struct net_device *dev) 
	 *

	 */

	reg_mcr = flexcan_read(&regs->mcr);

	reg_mcr &= ~FLEXCAN_MCR_MAXMB(0xff);

	reg_mcr |= FLEXCAN_MCR_FRZ | FLEXCAN_MCR_FEN | FLEXCAN_MCR_HALT |

		FLEXCAN_MCR_SUPV | FLEXCAN_MCR_WRN_EN |

		FLEXCAN_MCR_IDAM_C | FLEXCAN_MCR_SRX_DIS;

		FLEXCAN_MCR_IDAM_C | FLEXCAN_MCR_SRX_DIS |

		FLEXCAN_MCR_MAXMB(FLEXCAN_TX_BUF_ID);

	netdev_dbg(dev, "%s: writing mcr=0x%08x", __func__, reg_mcr);

	flexcan_write(reg_mcr, &regs->mcr);
@@ -771,6 +773,10 @@ static int flexcan_chip_start(struct net_device *dev) 
	netdev_dbg(dev, "%s: writing ctrl=0x%08x", __func__, reg_ctrl);

	flexcan_write(reg_ctrl, &regs->ctrl);



	/* Abort any pending TX, mark Mailbox as INACTIVE */

	flexcan_write(FLEXCAN_MB_CNT_CODE(0x4),

		      &regs->cantxfg[FLEXCAN_TX_BUF_ID].can_ctrl);



	/* acceptance mask/acceptance code (accept everything) */

	flexcan_write(0x0, &regs->rxgmask);

	flexcan_write(0x0, &regs->rx14mask);