flexcan driver issue

mohammedtalha — Mon, 02 Jul 2018 14:50:15 GMT

I'm working with udoo quad (IMX6q). I've got the can bus up and running. However i have run into a similar issue referred to in this blog post

https://community.nxp.com/message/432806?q=flexcan%20bug%20atomic

iMX6 FlexCAN generates 'BUG: scheduling while atomic' on every CAN send

[ 187.633144] BUG: scheduling while atomic: swapper/0/0/0x00000102
[ 254.513103] INFO: rcu_preempt detected stalls on CPUs/tasks: { 0} (detected by 1, t=2439 jiffies, g=4294967258, c=4294967257, q=2)
[ 254.524955] Task dump for CPU 0:
[ 254.528201] swapper/0 D 804e8630 0 0 0 0x00000002

i'm currently working with udooneo(imx6sx) and udooquad(imx6q). Applying the patch suggested in the post above fixed the issue on imx6sx board. But on udooquad it has become intermittent. It happens sometimes on "ifconfig can0 up" or when the communication is started. Below is the patch i have applied to both imx6sx and imx6q. I'm using kernel 3.14.56-r0 (yocto poky distro).

---
drivers/net/can/flexcan.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index 8de484b..42c8e63 100644
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -340,7 +340,7 @@ static int flexcan_chip_enable(struct flexcan_priv *priv)
flexcan_write(reg, &regs->mcr);

while (timeout-- && (flexcan_read(&regs->mcr) & FLEXCAN_MCR_LPM_ACK))
- usleep_range(10, 20);
+ udelay(10);

if (flexcan_read(&regs->mcr) & FLEXCAN_MCR_LPM_ACK)
return -ETIMEDOUT;
@@ -359,7 +359,7 @@ static int flexcan_chip_disable(struct flexcan_priv *priv)
flexcan_write(reg, &regs->mcr);

while (timeout-- && !(flexcan_read(&regs->mcr) & FLEXCAN_MCR_LPM_ACK))
- usleep_range(10, 20);
+ udelay(10);

if (!(flexcan_read(&regs->mcr) & FLEXCAN_MCR_LPM_ACK))
return -ETIMEDOUT;
@@ -378,7 +378,7 @@ static int flexcan_chip_freeze(struct flexcan_priv *priv)
flexcan_write(reg, &regs->mcr);

while (timeout-- && !(flexcan_read(&regs->mcr) & FLEXCAN_MCR_FRZ_ACK))
- usleep_range(100, 200);
+ udelay(100);

if (!(flexcan_read(&regs->mcr) & FLEXCAN_MCR_FRZ_ACK))
return -ETIMEDOUT;
@@ -397,7 +397,7 @@ static int flexcan_chip_unfreeze(struct flexcan_priv *priv)
flexcan_write(reg, &regs->mcr);

while (timeout-- && (flexcan_read(&regs->mcr) & FLEXCAN_MCR_FRZ_ACK))
- usleep_range(10, 20);
+ udelay(10);

if (flexcan_read(&regs->mcr) & FLEXCAN_MCR_FRZ_ACK)
return -ETIMEDOUT;
@@ -412,7 +412,7 @@ static int flexcan_chip_softreset(struct flexcan_priv *priv)

flexcan_write(FLEXCAN_MCR_SOFTRST, &regs->mcr);
while (timeout-- && (flexcan_read(&regs->mcr) & FLEXCAN_MCR_SOFTRST))
- usleep_range(10, 20);
+ udelay(10);

if (flexcan_read(&regs->mcr) & FLEXCAN_MCR_SOFTRST)
return -ETIMEDOUT;
--
2.7.4

Re: flexcan driver issue

igorpadykov — Mon, 02 Jul 2018 23:13:44 GMT

Hi Mohammed

3.14.56 kernel not is maintained by nxp, recommended to try with official bsps

described on below link, for example L3.14.52

linux-imx - i.MX Linux kernel

https://www.nxp.com/support/developer-resources/run-time-software/i.mx-developer-resources/i.mx-6series-i.mx-7series-software-and-development-tool-resources:IMX_SW

Best regards
igor
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