Re: [PATCH] media: st_rc: Handle errors of clk_prepare_enable()

From: Sean Young
Date: Mon May 31 2021 - 06:10:18 EST


On Sat, May 15, 2021 at 03:39:09PM +0300, Evgeny Novikov wrote:
> Hadle errors of clk_prepare_enable() in st_rc_hardware_init() and its
> callers.
>
> Found by Linux Driver Verification project (linuxtesting.org).
>
> Signed-off-by: Evgeny Novikov <novikov@xxxxxxxxx>
> ---
> drivers/media/rc/st_rc.c | 20 ++++++++++++++++----
> 1 file changed, 16 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/media/rc/st_rc.c b/drivers/media/rc/st_rc.c
> index 3237fef5d502..f524fcf55acf 100644
> --- a/drivers/media/rc/st_rc.c
> +++ b/drivers/media/rc/st_rc.c
> @@ -157,8 +157,9 @@ static irqreturn_t st_rc_rx_interrupt(int irq, void *data)
> return IRQ_HANDLED;
> }
>
> -static void st_rc_hardware_init(struct st_rc_device *dev)
> +static int st_rc_hardware_init(struct st_rc_device *dev)
> {
> + int ret;
> int baseclock, freqdiff;
> unsigned int rx_max_symbol_per = MAX_SYMB_TIME;
> unsigned int rx_sampling_freq_div;
> @@ -166,7 +167,10 @@ static void st_rc_hardware_init(struct st_rc_device *dev)
> /* Enable the IP */
> reset_control_deassert(dev->rstc);
>
> - clk_prepare_enable(dev->sys_clock);
> + ret = clk_prepare_enable(dev->sys_clock);
> + if (ret)
> + return ret;

Now if probe or resume fails because of clk_prepare_enable() failing, no
error is logged. Please add a dev_err().

Thanks

Sean

> +
> baseclock = clk_get_rate(dev->sys_clock);
>
> /* IRB input pins are inverted internally from high to low. */
> @@ -184,6 +188,8 @@ static void st_rc_hardware_init(struct st_rc_device *dev)
> }
>
> writel(rx_max_symbol_per, dev->rx_base + IRB_MAX_SYM_PERIOD);
> +
> + return 0;
> }
>
> static int st_rc_remove(struct platform_device *pdev)
> @@ -287,7 +293,9 @@ static int st_rc_probe(struct platform_device *pdev)
>
> rc_dev->dev = dev;
> platform_set_drvdata(pdev, rc_dev);
> - st_rc_hardware_init(rc_dev);
> + ret = st_rc_hardware_init(rc_dev);
> + if (ret)
> + goto err;
>
> rdev->allowed_protocols = RC_PROTO_BIT_ALL_IR_DECODER;
> /* rx sampling rate is 10Mhz */
> @@ -359,6 +367,7 @@ static int st_rc_suspend(struct device *dev)
>
> static int st_rc_resume(struct device *dev)
> {
> + int ret;
> struct st_rc_device *rc_dev = dev_get_drvdata(dev);
> struct rc_dev *rdev = rc_dev->rdev;
>
> @@ -367,7 +376,10 @@ static int st_rc_resume(struct device *dev)
> rc_dev->irq_wake = 0;
> } else {
> pinctrl_pm_select_default_state(dev);
> - st_rc_hardware_init(rc_dev);
> + ret = st_rc_hardware_init(rc_dev);
> + if (ret)
> + return ret;
> +
> if (rdev->users) {
> writel(IRB_RX_INTS, rc_dev->rx_base + IRB_RX_INT_EN);
> writel(0x01, rc_dev->rx_base + IRB_RX_EN);
> --
> 2.26.2