[PATCH] can: flexcan: fix chip freeze for missing bitrate

From: Angelo Dureghello <angelo@kernel-space.org>
To: wg@grandegger.com
Cc: qiangqing.zhang@nxp.com, mkl@pengutronix.de,
	linux-can@vger.kernel.org,
	Angelo Dureghello <angelo@kernel-space.org>
Subject: [PATCH] can: flexcan: fix chip freeze for missing bitrate
Date: Tue, 16 Mar 2021 00:15:10 +0100	[thread overview]
Message-ID: <20210315231510.650593-1-angelo@kernel-space.org> (raw)

For cases when flexcan is built-in, bitrate is still not set
at registering. So flexcan_chip_freeze() generates:

[    1.860000] *** ZERO DIVIDE ***   FORMAT=4
[    1.860000] Current process id is 1
[    1.860000] BAD KERNEL TRAP: 00000000
[    1.860000] PC: [<402e70c8>] flexcan_chip_freeze+0x1a/0xa8

To allow chip freeze, using an hardcoded timeout when bitrate is still
not set.

Signed-off-by: Angelo Dureghello <angelo@kernel-space.org>
---
 drivers/net/can/flexcan.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index 134c05757a3b..bb41ff3d2d1e 100644
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -697,9 +697,13 @@ static int flexcan_chip_disable(struct flexcan_priv *priv)
 static int flexcan_chip_freeze(struct flexcan_priv *priv)
 {
 	struct flexcan_regs __iomem *regs = priv->regs;
-	unsigned int timeout = 1000 * 1000 * 10 / priv->can.bittiming.bitrate;
+	unsigned int timeout;
+	u32 bitrate = priv->can.bittiming.bitrate;
 	u32 reg;
 
+	timeout = bitrate ? 1000 * 1000 * 10 / bitrate :
+			FLEXCAN_TIMEOUT_US / 10;
+
 	reg = priv->read(&regs->mcr);
 	reg |= FLEXCAN_MCR_FRZ | FLEXCAN_MCR_HALT;
 	priv->write(reg, &regs->mcr);
-- 
2.30.1

