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From:   Adrian Hunter <adrian.hunter@intel.com>
To:     "Martin K . Petersen" <martin.petersen@oracle.com>,
        "James E . J . Bottomley" <jejb@linux.ibm.com>
Cc:     linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
        Alim Akhtar <alim.akhtar@samsung.com>,
        Avri Altman <avri.altman@wdc.com>,
        Bean Huo <huobean@gmail.com>, Can Guo <cang@codeaurora.org>,
        Stanley Chu <stanley.chu@mediatek.com>
Subject: [PATCH V4 2/2] scsi: ufs: Allow an error return value from ->device_reset()
Date:   Tue,  3 Nov 2020 16:14:03 +0200
Message-Id: <20201103141403.2142-3-adrian.hunter@intel.com>
In-Reply-To: <20201103141403.2142-1-adrian.hunter@intel.com>
References: <20201103141403.2142-1-adrian.hunter@intel.com>
Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki
Precedence: bulk

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@intel.com>
---
 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);
 	}
 }
 
-- 
2.17.1