[U-Boot] [PATCH 1/3] dm: timer: refuse timers with zero clock_rate

[Bin Meng <bmeng.cn@gmail.com>]

On Thu, Jan 7, 2016 at 1:33 AM, Stephen Warren <swarren@wwwdotorg.org> wrote:
> From: Stephen Warren <swarren@nvidia.com>
>
> If a timer has a zero clock_rate, get_tbclk() will return zero for it,
> which will cause tick_to_time() to perform a division-by-zero, which will
> crash U-Boot.
>
> Signed-off-by: Stephen Warren <swarren@nvidia.com>
> ---
>  drivers/timer/timer-uclass.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
>
> diff --git a/drivers/timer/timer-uclass.c b/drivers/timer/timer-uclass.c
> index aca421bdea33..0771562c600d 100644
> --- a/drivers/timer/timer-uclass.c
> +++ b/drivers/timer/timer-uclass.c
> @@ -47,6 +47,16 @@ static int timer_pre_probe(struct udevice *dev)
>         return 0;
>  }
>
> +static int timer_post_probe(struct udevice *dev)
> +{
> +       struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
> +
> +       if (!uc_priv->clock_rate)
> +               return -EINVAL;

Should we just panic here?

> +
> +       return 0;
> +}
> +
>  u64 timer_conv_64(u32 count)
>  {
>         /* increment tbh if tbl has rolled over */
> @@ -60,5 +70,6 @@ UCLASS_DRIVER(timer) = {
>         .id             = UCLASS_TIMER,
>         .name           = "timer",
>         .pre_probe      = timer_pre_probe,
> +       .post_probe     = timer_post_probe,
>         .per_device_auto_alloc_size = sizeof(struct timer_dev_priv),
>  };
> --

Regards,
Bin