From 7ad0f53a394ba829e45682c2e21175791e36b649 Mon Sep 17 00:00:00 2001 From: Pankaj Bansal Date: Mon, 13 Aug 2018 23:50:48 +0530 Subject: can: flexcan: flexcan_chip_start(): enable loopback mode in flexcan Self reception disable bit needs to be cleared for loopback mode to work in flexcan. Signed-off-by: Pankaj Bansal Signed-off-by: Marc Kleine-Budde --- drivers/net/can/flexcan.c | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-) (limited to 'drivers/net/can/flexcan.c') diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c index cfdeb5bc77b7..f16668b8dd61 100644 --- a/drivers/net/can/flexcan.c +++ b/drivers/net/can/flexcan.c @@ -995,7 +995,6 @@ static int flexcan_chip_start(struct net_device *dev) * halt now * only supervisor access * enable warning int - * disable local echo * enable individual RX masking * choose format C * set max mailbox number @@ -1003,8 +1002,8 @@ static int flexcan_chip_start(struct net_device *dev) reg_mcr = priv->read(®s->mcr); reg_mcr &= ~FLEXCAN_MCR_MAXMB(0xff); reg_mcr |= FLEXCAN_MCR_FRZ | FLEXCAN_MCR_HALT | FLEXCAN_MCR_SUPV | - FLEXCAN_MCR_WRN_EN | FLEXCAN_MCR_SRX_DIS | FLEXCAN_MCR_IRMQ | - FLEXCAN_MCR_IDAM_C | FLEXCAN_MCR_MAXMB(FLEXCAN_TX_MB); + FLEXCAN_MCR_WRN_EN | FLEXCAN_MCR_IRMQ | FLEXCAN_MCR_IDAM_C | + FLEXCAN_MCR_MAXMB(FLEXCAN_TX_MB); /* MCR * @@ -1017,6 +1016,23 @@ static int flexcan_chip_start(struct net_device *dev) else reg_mcr |= FLEXCAN_MCR_FEN; + /* MCR + * + * NOTE: In loopback mode, the CAN_MCR[SRXDIS] cannot be + * asserted because this will impede the self reception + * of a transmitted message. This is not documented in + * earlier versions of flexcan block guide. + * + * Self Reception: + * - enable Self Reception for loopback mode + * (by clearing "Self Reception Disable" bit) + * - disable for normal operation + */ + if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK) + reg_mcr &= ~FLEXCAN_MCR_SRX_DIS; + else + reg_mcr |= FLEXCAN_MCR_SRX_DIS; + netdev_dbg(dev, "%s: writing mcr=0x%08x", __func__, reg_mcr); priv->write(reg_mcr, ®s->mcr); -- cgit v1.2.3-59-g8ed1b