Hi Tero,
On Wed, 2019-08-28 at 10:19 +0300, Tero Kristo wrote:
> Poll for reset completion status during de-assertion of reset, otherwise
> the IP in question might be accessed before it has left reset properly.
>
> Signed-off-by: Tero Kristo <t-kristo@xxxxxx>
> ---
> drivers/soc/ti/omap_prm.c | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/drivers/soc/ti/omap_prm.c b/drivers/soc/ti/omap_prm.c
> index fd5c431f8736..afeb70761b27 100644
> --- a/drivers/soc/ti/omap_prm.c
> +++ b/drivers/soc/ti/omap_prm.c
> @@ -127,6 +127,7 @@ static int omap_reset_deassert(struct reset_controller_dev *rcdev,
> u32 v;
> int st_bit;
> bool has_rstst;
> + int timeout = 0;
>
> if (!_is_valid_reset(reset, id))
> return -EINVAL;
> @@ -153,6 +154,25 @@ static int omap_reset_deassert(struct reset_controller_dev *rcdev,
> v &= ~(1 << id);
> writel_relaxed(v, reset->prm->base + reset->prm->data->rstctrl);
>
> + if (!has_rstst)
> + return 0;
> +
> + /* wait for the status to be set */
> + while (1) {
> + v = readl_relaxed(reset->prm->base + reset->prm->data->rstst);
> + v &= 1 << st_bit;
> + if (v)
> + break;
> + timeout++;
> + if (timeout > OMAP_RESET_MAX_WAIT) {
> + pr_err("%s: timedout waiting for %s:%lu\n", __func__,
> + dev_name(rcdev->dev), id);
> + return -EBUSY;
> + }
> +
> + udelay(1);
> + }
This looks like you could use
readl_relaxed_poll_timeout(_atomic)
regards
Philipp
