Re: [PATCH V4 2/2] scsi: ufs: Allow an error return value from ->device_reset()

From: Stanley Chu
Date: Tue Nov 03 2020 - 21:55:49 EST


Hi Adrian,

On Tue, 2020-11-03 at 16:14 +0200, Adrian Hunter wrote:
> It is simpler for drivers to provide a ->device_reset() callback
> irrespective of whether the GPIO, or firmware interface necessary to do the
> reset, is discovered during probe.
>
> Change ->device_reset() to return an error code. Drivers that provide
> the callback, but do not do the reset operation should return -EOPNOTSUPP.
>
> Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> ---
> drivers/scsi/ufs/ufs-mediatek.c | 4 +++-
> drivers/scsi/ufs/ufs-qcom.c | 6 ++++--
> drivers/scsi/ufs/ufshcd.h | 11 +++++++----
> 3 files changed, 14 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/scsi/ufs/ufs-mediatek.c b/drivers/scsi/ufs/ufs-mediatek.c
> index 8df73bc2f8cb..914a827a93ee 100644
> --- a/drivers/scsi/ufs/ufs-mediatek.c
> +++ b/drivers/scsi/ufs/ufs-mediatek.c
> @@ -743,7 +743,7 @@ static int ufs_mtk_link_startup_notify(struct ufs_hba *hba,
> return ret;
> }
>
> -static void ufs_mtk_device_reset(struct ufs_hba *hba)
> +static int ufs_mtk_device_reset(struct ufs_hba *hba)
> {
> struct arm_smccc_res res;
>
> @@ -764,6 +764,8 @@ static void ufs_mtk_device_reset(struct ufs_hba *hba)
> usleep_range(10000, 15000);
>
> dev_info(hba->dev, "device reset done\n");
> +
> + return 0;
> }
>
> static int ufs_mtk_link_set_hpm(struct ufs_hba *hba)
> diff --git a/drivers/scsi/ufs/ufs-qcom.c b/drivers/scsi/ufs/ufs-qcom.c
> index 9a19c6d15d3b..357c3b49321d 100644
> --- a/drivers/scsi/ufs/ufs-qcom.c
> +++ b/drivers/scsi/ufs/ufs-qcom.c
> @@ -1422,13 +1422,13 @@ static void ufs_qcom_dump_dbg_regs(struct ufs_hba *hba)
> *
> * Toggles the (optional) reset line to reset the attached device.
> */
> -static void ufs_qcom_device_reset(struct ufs_hba *hba)
> +static int ufs_qcom_device_reset(struct ufs_hba *hba)
> {
> struct ufs_qcom_host *host = ufshcd_get_variant(hba);
>
> /* reset gpio is optional */
> if (!host->device_reset)
> - return;
> + return -EOPNOTSUPP;
>
> /*
> * The UFS device shall detect reset pulses of 1us, sleep for 10us to
> @@ -1439,6 +1439,8 @@ static void ufs_qcom_device_reset(struct ufs_hba *hba)
>
> gpiod_set_value_cansleep(host->device_reset, 0);
> usleep_range(10, 15);
> +
> + return 0;
> }
>
> #if IS_ENABLED(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND)
> diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
> index 213be0667b59..5191d87f6263 100644
> --- a/drivers/scsi/ufs/ufshcd.h
> +++ b/drivers/scsi/ufs/ufshcd.h
> @@ -323,7 +323,7 @@ struct ufs_hba_variant_ops {
> int (*resume)(struct ufs_hba *, enum ufs_pm_op);
> void (*dbg_register_dump)(struct ufs_hba *hba);
> int (*phy_initialization)(struct ufs_hba *);
> - void (*device_reset)(struct ufs_hba *hba);
> + int (*device_reset)(struct ufs_hba *hba);
> void (*config_scaling_param)(struct ufs_hba *hba,
> struct devfreq_dev_profile *profile,
> void *data);
> @@ -1207,9 +1207,12 @@ static inline void ufshcd_vops_dbg_register_dump(struct ufs_hba *hba)
> static inline void ufshcd_vops_device_reset(struct ufs_hba *hba)
> {
> if (hba->vops && hba->vops->device_reset) {
> - hba->vops->device_reset(hba);
> - ufshcd_set_ufs_dev_active(hba);
> - ufshcd_update_reg_hist(&hba->ufs_stats.dev_reset, 0);
> + int err = hba->vops->device_reset(hba);
> +
> + if (!err)
> + ufshcd_set_ufs_dev_active(hba);
> + if (err != -EOPNOTSUPP)
> + ufshcd_update_reg_hist(&hba->ufs_stats.dev_reset, err);
> }
> }

For ufs-mediatek part and related flow,

Reviewed-by: Stanley Chu <stanley.chu@xxxxxxxxxxxx>