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

[Asutosh Das (asd)]

On 11/3/2020 6:14 AM, 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.hun...@intel.com>

Reviewed-by: Asutosh Das <asuto...@codeaurora.org>

---
  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);
        }
  }

--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
Linux Foundation Collaborative Project