[PATCH v10 4/6] scsi: ufs: Add core reset support

[Can Guo <cang@codeaurora.org>]

From: Dov Levenglick <dovl@codeaurora.org>

Enables core reset support. Add full initialization of the PHY and the
controller before initializing UFS PHY and during link recovery.

Signed-off-by: Dov Levenglick <dovl@codeaurora.org>
Signed-off-by: Amit Nischal <anischal@codeaurora.org>
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Can Guo <cang@codeaurora.org>
---
 drivers/scsi/ufs/ufs-qcom.c      | 30 ++++++++++++++++++++++++++++++
 drivers/scsi/ufs/ufshcd-pltfrm.c | 22 ++++++++++++++++++++++
 drivers/scsi/ufs/ufshcd.c        | 13 +++++++++++++
 drivers/scsi/ufs/ufshcd.h        | 12 ++++++++++++
 4 files changed, 77 insertions(+)

diff --git a/drivers/scsi/ufs/ufs-qcom.c b/drivers/scsi/ufs/ufs-qcom.c
index 2b38db2..698b92d 100644
--- a/drivers/scsi/ufs/ufs-qcom.c
+++ b/drivers/scsi/ufs/ufs-qcom.c
@@ -616,6 +616,35 @@ static int ufs_qcom_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 	return err;
 }
 
+static int ufs_qcom_core_reset(struct ufs_hba *hba)
+{
+	int ret = -ENOTSUPP;
+
+	if (!hba->core_reset) {
+		dev_err(hba->dev, "%s: failed, err = %d\n", __func__,
+				ret);
+		goto out;
+	}
+
+	ret = reset_control_assert(hba->core_reset);
+	if (ret) {
+		dev_err(hba->dev, "core_reset assert failed, err = %d\n",
+				ret);
+		goto out;
+	}
+
+	/* As per spec, delay is required to let reset assert go through */
+	usleep_range(1, 2);
+
+	ret = reset_control_deassert(hba->core_reset);
+	if (ret)
+		dev_err(hba->dev, "core_reset deassert failed, err = %d\n",
+				ret);
+
+out:
+	return ret;
+}
+
 struct ufs_qcom_dev_params {
 	u32 pwm_rx_gear;	/* pwm rx gear to work in */
 	u32 pwm_tx_gear;	/* pwm tx gear to work in */
@@ -1670,6 +1699,7 @@ static void ufs_qcom_dump_dbg_regs(struct ufs_hba *hba)
 	.apply_dev_quirks	= ufs_qcom_apply_dev_quirks,
 	.suspend		= ufs_qcom_suspend,
 	.resume			= ufs_qcom_resume,
+	.core_reset		= ufs_qcom_core_reset,
 	.dbg_register_dump	= ufs_qcom_dump_dbg_regs,
 };
 
diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c b/drivers/scsi/ufs/ufshcd-pltfrm.c
index e82bde0..dab11a7 100644
--- a/drivers/scsi/ufs/ufshcd-pltfrm.c
+++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
@@ -42,6 +42,22 @@
 
 #define UFSHCD_DEFAULT_LANES_PER_DIRECTION		2
 
+static int ufshcd_parse_reset_info(struct ufs_hba *hba)
+{
+	int ret = 0;
+
+	hba->core_reset = devm_reset_control_get_optional_exclusive(hba->dev,
+				"rst");
+	if (IS_ERR(hba->core_reset)) {
+		ret = PTR_ERR(hba->core_reset);
+		dev_err(hba->dev, "core_reset unavailable,err = %d\n",
+				ret);
+		hba->core_reset = NULL;
+	}
+
+	return ret;
+}
+
 static int ufshcd_parse_clock_info(struct ufs_hba *hba)
 {
 	int ret = 0;
@@ -340,6 +356,12 @@ int ufshcd_pltfrm_init(struct platform_device *pdev,
 		goto dealloc_host;
 	}
 
+	err = ufshcd_parse_reset_info(hba);
+	if (err) {
+		dev_err(&pdev->dev, "%s: reset parse failed %d\n",
+				__func__, err);
+	}
+
 	pm_runtime_set_active(&pdev->dev);
 	pm_runtime_enable(&pdev->dev);
 
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index a355d98..d18c3af 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -3657,6 +3657,15 @@ static int ufshcd_link_recovery(struct ufs_hba *hba)
 	ufshcd_set_eh_in_progress(hba);
 	spin_unlock_irqrestore(hba->host->host_lock, flags);
 
+	if (hba->core_reset) {
+		ret = ufshcd_vops_core_reset(hba);
+		if (ret)
+			dev_err(hba->dev,
+				"full reset returned %d, trying to recover the link\n",
+				ret);
+		return ret;
+	}
+
 	ret = ufshcd_host_reset_and_restore(hba);
 
 	spin_lock_irqsave(hba->host->host_lock, flags);
@@ -7948,6 +7957,10 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
 		goto exit_gating;
 	}
 
+	/* Reset controller to power on reset (POR) state */
+	if (hba->core_reset)
+		ufshcd_vops_core_reset(hba);
+
 	/* Host controller enable */
 	err = ufshcd_hba_enable(hba);
 	if (err) {
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index 1332e54..aa046a1 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -55,6 +55,7 @@
 #include <linux/clk.h>
 #include <linux/completion.h>
 #include <linux/regulator/consumer.h>
+#include <linux/reset.h>
 #include "unipro.h"
 
 #include <asm/irq.h>
@@ -295,6 +296,8 @@ struct ufs_pwr_mode_info {
  * @apply_dev_quirks: called to apply device specific quirks
  * @suspend: called during host controller PM callback
  * @resume: called during host controller PM callback
+ * @core_reset:  called before UFS PHY init and during link recovery for
+ *		 handling variant specific implementations of resetting the hci
  * @dbg_register_dump: used to dump controller debug information
  * @phy_initialization: used to initialize phys
  */
@@ -323,6 +326,7 @@ struct ufs_hba_variant_ops {
 	int	(*apply_dev_quirks)(struct ufs_hba *);
 	int     (*suspend)(struct ufs_hba *, enum ufs_pm_op);
 	int     (*resume)(struct ufs_hba *, enum ufs_pm_op);
+	int	(*core_reset)(struct ufs_hba *);
 	void	(*dbg_register_dump)(struct ufs_hba *hba);
 	int	(*phy_initialization)(struct ufs_hba *);
 };
@@ -678,6 +682,7 @@ struct ufs_hba {
 	bool is_urgent_bkops_lvl_checked;
 
 	struct rw_semaphore clk_scaling_lock;
+	struct reset_control *core_reset;
 	struct ufs_desc_size desc_size;
 };
 
@@ -979,6 +984,13 @@ static inline int ufshcd_vops_resume(struct ufs_hba *hba, enum ufs_pm_op op)
 	return 0;
 }
 
+static inline int ufshcd_vops_core_reset(struct ufs_hba *hba)
+{
+	if (hba->vops && hba->vops->core_reset)
+		return hba->vops->core_reset(hba);
+	return 0;
+}
+
 static inline void ufshcd_vops_dbg_register_dump(struct ufs_hba *hba)
 {
 	if (hba->vops && hba->vops->dbg_register_dump)
-- 
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