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SubjectRE: [PATCH] can: flexcan: fix timeout when set small bitrate
Date

Kindly Ping...

Reviewed-by: Dong Aisheng <aisheng.dong@nxp.com>

Best Regards,
Joakim Zhang

> -----Original Message-----
> From: Joakim Zhang
> Sent: 2019年1月31日 17:37
> To: mkl@pengutronix.de; linux-can@vger.kernel.org
> Cc: wg@grandegger.com; netdev@vger.kernel.org;
> linux-kernel@vger.kernel.org; dl-linux-imx <linux-imx@nxp.com>; Joakim
> Zhang <qiangqing.zhang@nxp.com>
> Subject: [PATCH] can: flexcan: fix timeout when set small bitrate
>
> Current we can meet timeout issue when setting a small bitrate like 10000 as
> follows on i.MX6UL EVK board (ipg clock = 66MHZ, per clock = 30MHZ):
> root@imx6ul7d:~# ip link set can0 up type can bitrate 10000 A link change
> request failed with some changes committed already.
> Interface can0 may have been left with an inconsistent configuration, please
> check.
> RTNETLINK answers: Connection timed out
>
> It is caused by calling of flexcan_chip_unfreeze() timeout.
>
> Originally the code is using usleep_range(10, 20) for unfreeze operation, but
> the patch (8badd65 can: flexcan: avoid calling usleep_range from interrupt
> context) changed it into udelay(10) which is only a half delay of before,
> there're also some other delay changes.
>
> After double to FLEXCAN_TIMEOUT_US to 100 can fix the issue.
>
> Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
> ---
> drivers/net/can/flexcan.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c index
> 2bca867bcfaa..1f2b4db7da88 100644
> --- a/drivers/net/can/flexcan.c
> +++ b/drivers/net/can/flexcan.c
> @@ -166,7 +166,7 @@
> #define FLEXCAN_MB_CNT_LENGTH(x) (((x) & 0xf) << 16)
> #define FLEXCAN_MB_CNT_TIMESTAMP(x) ((x) & 0xffff)
>
> -#define FLEXCAN_TIMEOUT_US (50)
> +#define FLEXCAN_TIMEOUT_US (100)
>
> /* FLEXCAN hardware feature flags
> *
> --
> 2.17.1

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