[PATCH v2 1/6] scsi: ufs: Flush exception event before suspend

[PATCH v2 1/6] scsi: ufs: Flush exception event before suspend

[Can Guo]

From: Sayali Lokhande <sayalil@codeaurora.org>

Exception event can be raised by the device when system
suspend is in progress. This will result in unclocked
register access in exception event handler as clocks will
be turned off during suspend. This change makes sure to flush
exception event handler work in suspend before disabling
clocks to avoid unclocked register access issue.

Signed-off-by: Sayali Lokhande <sayalil@codeaurora.org>
Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
Signed-off-by: Can Guo <cang@codeaurora.org>
---
 drivers/scsi/ufs/ufshcd.c | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 1201578..c2de29f 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -4760,8 +4760,15 @@ static void ufshcd_slave_destroy(struct scsi_device *sdev)
 			 * UFS device needs urgent BKOPs.
 			 */
 			if (!hba->pm_op_in_progress &&
-			    ufshcd_is_exception_event(lrbp->ucd_rsp_ptr))
-				schedule_work(&hba->eeh_work);
+			    ufshcd_is_exception_event(lrbp->ucd_rsp_ptr)) {
+				/*
+				 * Prevent suspend once eeh_work is scheduled
+				 * to avoid deadlock between ufshcd_suspend
+				 * and exception event handler.
+				 */
+				if (schedule_work(&hba->eeh_work))
+					pm_runtime_get_noresume(hba->dev);
+			}
 			break;
 		case UPIU_TRANSACTION_REJECT_UPIU:
 			/* TODO: handle Reject UPIU Response */
@@ -5215,7 +5222,14 @@ static void ufshcd_exception_event_handler(struct work_struct *work)
 
 out:
 	scsi_unblock_requests(hba->host);
-	pm_runtime_put_sync(hba->dev);
+	/*
+	 * pm_runtime_get_noresume is called while scheduling
+	 * eeh_work to avoid suspend racing with exception work.
+	 * Hence decrement usage counter using pm_runtime_put_noidle
+	 * to allow suspend on completion of exception event handler.
+	 */
+	pm_runtime_put_noidle(hba->dev);
+	pm_runtime_put(hba->dev);
 	return;
 }
 
@@ -7901,6 +7915,7 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 			goto enable_gating;
 	}
 
+	flush_work(&hba->eeh_work);
 	ret = ufshcd_link_state_transition(hba, req_link_state, 1);
 	if (ret)
 		goto set_dev_active;
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

[PATCH v2 2/6] scsi: ufs: set load before setting voltage in regulators

[Can Guo]

From: Asutosh Das <asutoshd@codeaurora.org>

This sequence change is required to avoid dips in voltage
during boot-up.

Apparently, this dip is caused because in the original
sequence, the regulators are initialized in lpm mode.
And then when the load is set to high, and more current
is drawn, than is allowed in lpm, the dip is seen.

Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
Signed-off-by: Can Guo <cang@codeaurora.org>
---
 drivers/scsi/ufs/ufshcd.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index c2de29f..c386c2d 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -7225,6 +7225,11 @@ static int ufshcd_config_vreg(struct device *dev,
 	name = vreg->name;
 
 	if (regulator_count_voltages(reg) > 0) {
+		uA_load = on ? vreg->max_uA : 0;
+		ret = ufshcd_config_vreg_load(dev, vreg, uA_load);
+		if (ret)
+			goto out;
+
 		if (vreg->min_uV && vreg->max_uV) {
 			min_uV = on ? vreg->min_uV : 0;
 			ret = regulator_set_voltage(reg, min_uV, vreg->max_uV);
@@ -7235,11 +7240,6 @@ static int ufshcd_config_vreg(struct device *dev,
 				goto out;
 			}
 		}
-
-		uA_load = on ? vreg->max_uA : 0;
-		ret = ufshcd_config_vreg_load(dev, vreg, uA_load);
-		if (ret)
-			goto out;
 	}
 out:
 	return ret;
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

[PATCH v2 3/6] scsi: ufs: Remove the check before call setup clock notify vops

[Can Guo]

The functionality of vendor specific ops should be handled properly in
platform specific driver, but should not count on the UFS driver.

Signed-off-by: Can Guo <cang@codeaurora.org>
---
 drivers/scsi/ufs/ufshcd.c | 26 ++++++--------------------
 1 file changed, 6 insertions(+), 20 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index c386c2d..4dfd705 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -7379,16 +7379,9 @@ static int __ufshcd_setup_clocks(struct ufs_hba *hba, bool on,
 	if (list_empty(head))
 		goto out;
 
-	/*
-	 * vendor specific setup_clocks ops may depend on clocks managed by
-	 * this standard driver hence call the vendor specific setup_clocks
-	 * before disabling the clocks managed here.
-	 */
-	if (!on) {
-		ret = ufshcd_vops_setup_clocks(hba, on, PRE_CHANGE);
-		if (ret)
-			return ret;
-	}
+	ret = ufshcd_vops_setup_clocks(hba, on, PRE_CHANGE);
+	if (ret)
+		return ret;
 
 	list_for_each_entry(clki, head, list) {
 		if (!IS_ERR_OR_NULL(clki->clk)) {
@@ -7412,16 +7405,9 @@ static int __ufshcd_setup_clocks(struct ufs_hba *hba, bool on,
 		}
 	}
 
-	/*
-	 * vendor specific setup_clocks ops may depend on clocks managed by
-	 * this standard driver hence call the vendor specific setup_clocks
-	 * after enabling the clocks managed here.
-	 */
-	if (on) {
-		ret = ufshcd_vops_setup_clocks(hba, on, POST_CHANGE);
-		if (ret)
-			return ret;
-	}
+	ret = ufshcd_vops_setup_clocks(hba, on, POST_CHANGE);
+	if (ret)
+		return ret;
 
 out:
 	if (ret) {
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

[PATCH v2 4/6] scsi: ufs-qcom: Adjust bus bandwidth voting and unvoting

[Can Guo]

The bus bandwidth voting is required to be done before the bus clocks
are enabled, and the unvoting is required to be done only after the bus
clocks are disabled.

Signed-off-by: Can Guo <cang@codeaurora.org>
---
 drivers/scsi/ufs/ufs-qcom.c | 57 +++++++++++++++++++++++++++++++--------------
 1 file changed, 39 insertions(+), 18 deletions(-)

diff --git a/drivers/scsi/ufs/ufs-qcom.c b/drivers/scsi/ufs/ufs-qcom.c
index c69c29a1c..85d7c17 100644
--- a/drivers/scsi/ufs/ufs-qcom.c
+++ b/drivers/scsi/ufs/ufs-qcom.c
@@ -38,7 +38,6 @@ enum {
 
 static struct ufs_qcom_host *ufs_qcom_hosts[MAX_UFS_QCOM_HOSTS];
 
-static int ufs_qcom_set_bus_vote(struct ufs_qcom_host *host, int vote);
 static void ufs_qcom_get_default_testbus_cfg(struct ufs_qcom_host *host);
 static int ufs_qcom_set_dme_vs_core_clk_ctrl_clear_div(struct ufs_hba *hba,
 						       u32 clk_cycles);
@@ -674,7 +673,7 @@ static void ufs_qcom_get_speed_mode(struct ufs_pa_layer_attr *p, char *result)
 	}
 }
 
-static int ufs_qcom_set_bus_vote(struct ufs_qcom_host *host, int vote)
+static int __ufs_qcom_set_bus_vote(struct ufs_qcom_host *host, int vote)
 {
 	int err = 0;
 
@@ -705,7 +704,7 @@ static int ufs_qcom_update_bus_bw_vote(struct ufs_qcom_host *host)
 
 	vote = ufs_qcom_get_bus_vote(host, mode);
 	if (vote >= 0)
-		err = ufs_qcom_set_bus_vote(host, vote);
+		err = __ufs_qcom_set_bus_vote(host, vote);
 	else
 		err = vote;
 
@@ -716,6 +715,35 @@ static int ufs_qcom_update_bus_bw_vote(struct ufs_qcom_host *host)
 	return err;
 }
 
+static int ufs_qcom_set_bus_vote(struct ufs_hba *hba, bool on)
+{
+	struct ufs_qcom_host *host = ufshcd_get_variant(hba);
+	int vote, err;
+
+	/*
+	 * In case ufs_qcom_init() is not yet done, simply ignore.
+	 * This ufs_qcom_set_bus_vote() shall be called from
+	 * ufs_qcom_init() after init is done.
+	 */
+	if (!host)
+		return 0;
+
+	if (on) {
+		vote = host->bus_vote.saved_vote;
+		if (vote == host->bus_vote.min_bw_vote)
+			ufs_qcom_update_bus_bw_vote(host);
+	} else {
+		vote = host->bus_vote.min_bw_vote;
+	}
+
+	err = __ufs_qcom_set_bus_vote(host, vote);
+	if (err)
+		dev_err(hba->dev, "%s: set bus vote failed %d\n",
+				 __func__, err);
+
+	return err;
+}
+
 static ssize_t
 show_ufs_to_mem_max_bus_bw(struct device *dev, struct device_attribute *attr,
 			char *buf)
@@ -792,7 +820,7 @@ static int ufs_qcom_update_bus_bw_vote(struct ufs_qcom_host *host)
 	return 0;
 }
 
-static int ufs_qcom_set_bus_vote(struct ufs_qcom_host *host, int vote)
+static int ufs_qcom_set_bus_vote(struct ufs_hba *host, bool on)
 {
 	return 0;
 }
@@ -1030,8 +1058,7 @@ static int ufs_qcom_setup_clocks(struct ufs_hba *hba, bool on,
 				 enum ufs_notify_change_status status)
 {
 	struct ufs_qcom_host *host = ufshcd_get_variant(hba);
-	int err;
-	int vote = 0;
+	int err = 0;
 
 	/*
 	 * In case ufs_qcom_init() is not yet done, simply ignore.
@@ -1041,28 +1068,21 @@ static int ufs_qcom_setup_clocks(struct ufs_hba *hba, bool on,
 	if (!host)
 		return 0;
 
-	if (on && (status == POST_CHANGE)) {
+	if (on && (status == PRE_CHANGE)) {
+		err = ufs_qcom_set_bus_vote(hba, true);
+	} else if (on && (status == POST_CHANGE)) {
 		/* enable the device ref clock for HS mode*/
 		if (ufshcd_is_hs_mode(&hba->pwr_info))
 			ufs_qcom_dev_ref_clk_ctrl(host, true);
-		vote = host->bus_vote.saved_vote;
-		if (vote == host->bus_vote.min_bw_vote)
-			ufs_qcom_update_bus_bw_vote(host);
-
 	} else if (!on && (status == PRE_CHANGE)) {
 		if (!ufs_qcom_is_link_active(hba)) {
 			/* disable device ref_clk */
 			ufs_qcom_dev_ref_clk_ctrl(host, false);
 		}
-
-		vote = host->bus_vote.min_bw_vote;
+	} else if (!on && (status == POST_CHANGE)) {
+		err = ufs_qcom_set_bus_vote(hba, false);
 	}
 
-	err = ufs_qcom_set_bus_vote(host, vote);
-	if (err)
-		dev_err(hba->dev, "%s: set bus vote failed %d\n",
-				__func__, err);
-
 	return err;
 }
 
@@ -1238,6 +1258,7 @@ static int ufs_qcom_init(struct ufs_hba *hba)
 	ufs_qcom_set_caps(hba);
 	ufs_qcom_advertise_quirks(hba);
 
+	ufs_qcom_set_bus_vote(hba, true);
 	ufs_qcom_setup_clocks(hba, true, POST_CHANGE);
 
 	if (hba->dev->id < MAX_UFS_QCOM_HOSTS)
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

[PATCH v2 5/6] scsi: ufs: Add dev ref clock gating wait time support

[Can Guo]

In UFS version 3.0, a newly added attribute bRefClkGatingWaitTime defines
the minimum time for which the reference clock is required by device during
transition to LS-MODE or HIBERN8 state. Make this change to reflect the new
requirement by adding delays before turning off the clock.

Signed-off-by: Can Guo <cang@codeaurora.org>
---
 drivers/scsi/ufs/ufs.h    |  3 +++
 drivers/scsi/ufs/ufshcd.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+)

diff --git a/drivers/scsi/ufs/ufs.h b/drivers/scsi/ufs/ufs.h
index 3327981..385bac8 100644
--- a/drivers/scsi/ufs/ufs.h
+++ b/drivers/scsi/ufs/ufs.h
@@ -168,6 +168,7 @@ enum attr_idn {
 	QUERY_ATTR_IDN_FFU_STATUS		= 0x14,
 	QUERY_ATTR_IDN_PSA_STATE		= 0x15,
 	QUERY_ATTR_IDN_PSA_DATA_SIZE		= 0x16,
+	QUERY_ATTR_IDN_REF_CLK_GATING_WAIT_TIME	= 0x17,
 };
 
 /* Descriptor idn for Query requests */
@@ -530,6 +531,8 @@ struct ufs_dev_info {
 	bool f_power_on_wp_en;
 	/* Keeps information if any of the LU is power on write protected */
 	bool is_lu_power_on_wp;
+	u16 spec_version;
+	u32 clk_gating_wait_us;
 };
 
 #define MAX_MODEL_LEN 16
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 4dfd705..d2d56f8 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -91,6 +91,9 @@
 /* default delay of autosuspend: 2000 ms */
 #define RPM_AUTOSUSPEND_DELAY_MS 2000
 
+/* Default value of wait time before gating device ref clock */
+#define UFSHCD_REF_CLK_GATING_WAIT_US 0xFF /* microsecs */
+
 #define ufshcd_toggle_vreg(_dev, _vreg, _on)				\
 	({                                                              \
 		int _ret;                                               \
@@ -3352,6 +3355,37 @@ static inline int ufshcd_read_unit_desc_param(struct ufs_hba *hba,
 				      param_offset, param_read_buf, param_size);
 }
 
+static int ufshcd_get_ref_clk_gating_wait(struct ufs_hba *hba)
+{
+	int err = 0;
+	u32 gating_wait = UFSHCD_REF_CLK_GATING_WAIT_US;
+
+	if (hba->dev_info.spec_version >= 0x300) {
+		err = ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_READ_ATTR,
+				QUERY_ATTR_IDN_REF_CLK_GATING_WAIT_TIME, 0, 0,
+				&gating_wait);
+		if (err)
+			dev_err(hba->dev, "Failed reading bRefClkGatingWait. err = %d, use default %uus\n",
+					 err, gating_wait);
+
+		if (gating_wait == 0) {
+			gating_wait = UFSHCD_REF_CLK_GATING_WAIT_US;
+			dev_err(hba->dev, "Undefined ref clk gating wait time, use default %uus\n",
+					 gating_wait);
+		}
+
+		/*
+		 * bRefClkGatingWaitTime defines the minimum time for which the
+		 * reference clock is required by device during transition from
+		 * HS-MODE to LS-MODE or HIBERN8 state. Give it more time to be
+		 * on the safe side.
+		 */
+		hba->dev_info.clk_gating_wait_us = gating_wait + 50;
+	}
+
+	return err;
+}
+
 /**
  * ufshcd_memory_alloc - allocate memory for host memory space data structures
  * @hba: per adapter instance
@@ -6623,6 +6657,10 @@ static int ufs_get_device_desc(struct ufs_hba *hba,
 	dev_desc->wmanufacturerid = desc_buf[DEVICE_DESC_PARAM_MANF_ID] << 8 |
 				     desc_buf[DEVICE_DESC_PARAM_MANF_ID + 1];
 
+	/* getting Specification Version in big endian format */
+	hba->dev_info.spec_version = desc_buf[DEVICE_DESC_PARAM_SPEC_VER] << 8 |
+				      desc_buf[DEVICE_DESC_PARAM_SPEC_VER + 1];
+
 	model_index = desc_buf[DEVICE_DESC_PARAM_PRDCT_NAME];
 	err = ufshcd_read_string_desc(hba, model_index,
 				      &dev_desc->model, SD_ASCII_STD);
@@ -7041,6 +7079,9 @@ static int ufshcd_probe_hba(struct ufs_hba *hba)
 
 		/* clear any previous UFS device information */
 		memset(&hba->dev_info, 0, sizeof(hba->dev_info));
+
+		ufshcd_get_ref_clk_gating_wait(hba);
+
 		if (!ufshcd_query_flag_retry(hba, UPIU_QUERY_OPCODE_READ_FLAG,
 				QUERY_FLAG_IDN_PWR_ON_WPE, &flag))
 			hba->dev_info.f_power_on_wp_en = flag;
@@ -7373,12 +7414,17 @@ static int __ufshcd_setup_clocks(struct ufs_hba *hba, bool on,
 	struct ufs_clk_info *clki;
 	struct list_head *head = &hba->clk_list_head;
 	unsigned long flags;
+	unsigned long gating_wait;
 	ktime_t start = ktime_get();
 	bool clk_state_changed = false;
 
 	if (list_empty(head))
 		goto out;
 
+	gating_wait = (unsigned long)hba->dev_info.clk_gating_wait_us;
+	if (!on && !skip_ref_clk && !!gating_wait)
+		usleep_range(gating_wait, gating_wait + 10);
+
 	ret = ufshcd_vops_setup_clocks(hba, on, PRE_CHANGE);
 	if (ret)
 		return ret;
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

[PATCH v2 6/6] scsi: ufs: Fix ufshcd_hold() caused scheduling while atomic

[Can Guo]

The async version of ufshcd_hold(async == true), which is only called
in queuecommand path as for now, is expected to work in atomic context,
thus it should not sleep or schedule out. When it runs into the condition
that clocks are ON but link is still in hibern8 state, it should bail out
without flushing the clock ungate work.

Signed-off-by: Can Guo <cang@codeaurora.org>
---
 drivers/scsi/ufs/ufshcd.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index d2d56f8..3910c58 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1545,6 +1545,11 @@ int ufshcd_hold(struct ufs_hba *hba, bool async)
 		 */
 		if (ufshcd_can_hibern8_during_gating(hba) &&
 		    ufshcd_is_link_hibern8(hba)) {
+			if (async) {
+				rc = -EAGAIN;
+				hba->clk_gating.active_reqs--;
+				break;
+			}
 			spin_unlock_irqrestore(hba->host->host_lock, flags);
 			flush_work(&hba->clk_gating.ungate_work);
 			spin_lock_irqsave(hba->host->host_lock, flags);
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project