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    SubjectRe: [PATCH v3 3/4] can: flexcan: switch on clocks before accessing ecr register
    On 07/15/2014 03:54 PM, Lothar Waßmann wrote:
    > Hi,
    >
    > Stefan Agner wrote:
    >> Reported-by: Ashutosh Singh <ashuleapyear@gmail.com>
    >> Suggested-by: Marc Kleine-Budde <mkl@pengutronix.de>
    >> [stefan@agner.ch: added return check for clk_enable_prepare]
    >>
    >> Signed-off-by: Stefan Agner <stefan@agner.ch>
    >> ---
    >> drivers/net/can/flexcan.c | 18 ++++++++++++++++--
    >> 1 file changed, 16 insertions(+), 2 deletions(-)
    >>
    >> diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
    >> index f425ec2..89745aa 100644
    >> --- a/drivers/net/can/flexcan.c
    >> +++ b/drivers/net/can/flexcan.c
    >> @@ -383,12 +383,26 @@ static int flexcan_get_berr_counter(const struct net_device *dev,
    >> {
    >> const struct flexcan_priv *priv = netdev_priv(dev);
    >> struct flexcan_regs __iomem *regs = priv->base;
    >> - u32 reg = flexcan_read(&regs->ecr);
    >> + u32 reg, err;
    >> +
    >> + err = clk_prepare_enable(priv->clk_ipg);
    >> + if (err)
    >> + return err;
    >> +
    >> + err = clk_prepare_enable(priv->clk_per);
    >> + if (err)
    >> + goto out_disable_ipg;
    >> +
    >> + reg = flexcan_read(&regs->ecr);
    >>
    > flexcan_get_berr_counter() may be called from interrupt context and
    > thus must not call any functions that can sleep.
    > Compiling the driver with CONFIG_DEBUG_ATOMIC_SLEEP would catch this!

    It's called from the NAPI softirq. I'll prepare a patch.

    Marc

    --
    Pengutronix e.K. | Marc Kleine-Budde |
    Industrial Linux Solutions | Phone: +49-231-2826-924 |
    Vertretung West/Dortmund | Fax: +49-5121-206917-5555 |
    Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de |

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