From 1d876acfd2cd445fe46e5bc4c531da2c6bef0c91 Mon Sep 17 00:00:00 2001 From: Marc Kleine-Budde Date: Fri, 4 Oct 2013 10:52:36 +0200 Subject: can: flexcan: flexcan_chip_start: fix regression, mark one MB for TX and abort pending TX MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit In patch 0d1862e 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 Cc: Lothar Waßmann Signed-off-by: Marc Kleine-Budde [backported for 3.0 kernel by Stefan Agner ] d5a7b406c529e4595ce03dc8f6dcf7fa36f106fa can: flexcan: flexcan_chip_start: fix regression, mark one MB for TX and abort pending TX --- drivers/net/can/flexcan.c | 17 ++++++----------- 1 file changed, 6 insertions(+), 11 deletions(-) diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c index 7ba80e5c00d1..9f5110d8fd63 100644 --- a/drivers/net/can/flexcan.c +++ b/drivers/net/can/flexcan.c @@ -738,7 +738,6 @@ static int flexcan_chip_start(struct net_device *dev) { struct flexcan_priv *priv = netdev_priv(dev); struct flexcan_regs __iomem *regs = priv->base; - unsigned int i; int err; u32 reg_mcr, reg_ctrl, reg_crl2, reg_mecr; @@ -774,10 +773,12 @@ static int flexcan_chip_start(struct net_device *dev) * */ reg_mcr = readl(®s->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_WAK_MSK | - FLEXCAN_MCR_SLF_WAK | FLEXCAN_MCR_SRX_DIS; + FLEXCAN_MCR_IDAM_C | FLEXCAN_MCR_SRX_DIS | + FLEXCAN_MCR_MAXMB(FLEXCAN_TX_BUF_ID); dev_dbg(dev->dev.parent, "%s: writing mcr=0x%08x", __func__, reg_mcr); writel(reg_mcr, ®s->mcr); @@ -807,15 +808,9 @@ static int flexcan_chip_start(struct net_device *dev) dev_dbg(dev->dev.parent, "%s: writing ctrl=0x%08x", __func__, reg_ctrl); writel(reg_ctrl, ®s->ctrl); - for (i = 0; i < ARRAY_SIZE(regs->cantxfg); i++) { - writel(0, ®s->cantxfg[i].can_ctrl); - writel(0, ®s->cantxfg[i].can_id); - writel(0, ®s->cantxfg[i].data[0]); - writel(0, ®s->cantxfg[i].data[1]); - - /* put MB into rx queue */ - writel(FLEXCAN_MB_CNT_CODE(0x4), ®s->cantxfg[i].can_ctrl); - } + /* Abort any pending TX, mark Mailbox as INACTIVE */ + writel(FLEXCAN_MB_CNT_CODE(0x4), + ®s->cantxfg[FLEXCAN_TX_BUF_ID].can_ctrl); /* acceptance mask/acceptance code (accept everything) */ writel(0x0, ®s->rxgmask); -- cgit v1.2.3