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    SubjectRe: [PATCH v3 3/4] can: flexcan: switch on clocks before accessing ecr register
    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!


    Lothar Waßmann
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