scsi: ufs: remove unwanted checks from hibern8 sequence

We are unnecessarily checking for the request/task doorbell status
during hibern8 enter/exit path but it's very important to have the
minimal latencies for hibern8 enter/exit in order to achieve agressive
power management strategies for UFS. So these unecessary checks are moved
out of this hot path.

Change-Id: Ibaeddca7bd516d71eb03b02a1fc1a86f05038f08
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
[venkatg@codeaurora.org: resolved trivial merge conflicts]
Signed-off-by: Venkat Gopalakrishnan <venkatg@codeaurora.org>

4 files changed, 113 insertions, 33 deletions

diff --git a/drivers/scsi/ufs/debugfs.c b/drivers/scsi/ufs/debugfs.c
index 8790f7a80682..c9479e979a8c 100644
--- a/drivers/scsi/ufs/debugfs.c
+++ b/drivers/scsi/ufs/debugfs.c
@@ -668,6 +668,7 @@ static ssize_t ufsdbg_power_mode_write(struct file *file,
 	loff_t buff_pos = 0;
 	int ret;
 	int idx = 0;
+	#define DOORBELL_CLR_TOUT_US	(1000 * 1000) /* 1 sec */
 
 	ret = simple_write_to_buffer(pwr_mode_str, BUFF_LINE_CAPACITY,
 		&buff_pos, ubuf, cnt);
@@ -695,7 +696,11 @@ static ssize_t ufsdbg_power_mode_write(struct file *file,
 		pwr_mode.lane_tx, pwr_mode.pwr_rx, pwr_mode.pwr_tx);
 
 	pm_runtime_get_sync(hba->dev);
-	ret = ufshcd_config_pwr_mode(hba, &pwr_mode);
+	scsi_block_requests(hba->host);
+	ret = ufshcd_wait_for_doorbell_clr(hba, DOORBELL_CLR_TOUT_US);
+	if (!ret)
+		ret = ufshcd_config_pwr_mode(hba, &pwr_mode);
+	scsi_unblock_requests(hba->host);
 	pm_runtime_put_sync(hba->dev);
 	if (ret == -EBUSY)
 		dev_err(hba->dev,
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index cdc434ea1287..7fb477d4f97e 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -2715,43 +2715,13 @@ static int ufshcd_uic_pwr_ctrl(struct ufs_hba *hba, struct uic_command *cmd)
 	unsigned long flags;
 	u8 status;
 	int ret;
-	u32 tm_doorbell;
-	u32 tr_doorbell;
-	bool uic_ready;
-	int retries = POWER_MODE_RETRIES;
 
 	mutex_lock(&hba->uic_cmd_mutex);
 	init_completion(&uic_async_done);
 	ufshcd_add_delay_before_dme_cmd(hba);
 
-	/*
-	 * Before changing the power mode there should be no outstanding
-	 * tasks/transfer requests. Verify by checking the doorbell registers
-	 * are clear.
-	 */
-	do {
-		spin_lock_irqsave(hba->host->host_lock, flags);
-		uic_ready = ufshcd_ready_for_uic_cmd(hba);
-		tm_doorbell = ufshcd_readl(hba, REG_UTP_TASK_REQ_DOOR_BELL);
-		tr_doorbell = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL);
-		if (!tm_doorbell && !tr_doorbell && uic_ready)
-			break;
-
-		spin_unlock_irqrestore(hba->host->host_lock, flags);
-		schedule();
-		retries--;
-	} while (retries && (tm_doorbell || tr_doorbell || !uic_ready));
-
-	if (!retries) {
-		dev_err(hba->dev,
-			"%s: too many retries waiting for doorbell to clear (tm=0x%x, tr=0x%x, uicrdy=%d)\n",
-			__func__, tm_doorbell, tr_doorbell, uic_ready);
-		ret = -EBUSY;
-		goto out;
-	}
-
+	spin_lock_irqsave(hba->host->host_lock, flags);
 	hba->uic_async_done = &uic_async_done;
-
 	ret = __ufshcd_send_uic_cmd(hba, cmd);
 	spin_unlock_irqrestore(hba->host->host_lock, flags);
 	if (ret) {
@@ -2792,6 +2762,52 @@ out:
 	return ret;
 }
 
+int ufshcd_wait_for_doorbell_clr(struct ufs_hba *hba, u64 wait_timeout_us)
+{
+	unsigned long flags;
+	int ret = 0;
+	u32 tm_doorbell;
+	u32 tr_doorbell;
+	bool timeout = false;
+	ktime_t start = ktime_get();
+
+	spin_lock_irqsave(hba->host->host_lock, flags);
+	if (hba->ufshcd_state != UFSHCD_STATE_OPERATIONAL) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	/*
+	 * Wait for all the outstanding tasks/transfer requests.
+	 * Verify by checking the doorbell registers are clear.
+	 */
+	do {
+		tm_doorbell = ufshcd_readl(hba, REG_UTP_TASK_REQ_DOOR_BELL);
+		tr_doorbell = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL);
+		if (!tm_doorbell && !tr_doorbell) {
+			timeout = false;
+			break;
+		}
+
+		spin_unlock_irqrestore(hba->host->host_lock, flags);
+		schedule();
+		if (ktime_to_us(ktime_sub(ktime_get(), start)) >
+		    wait_timeout_us)
+			timeout = true;
+		spin_lock_irqsave(hba->host->host_lock, flags);
+	} while (tm_doorbell || tr_doorbell);
+
+	if (timeout) {
+		dev_err(hba->dev,
+			"%s: timedout waiting for doorbell to clear (tm=0x%x, tr=0x%x)\n",
+			__func__, tm_doorbell, tr_doorbell);
+		ret = -EBUSY;
+	}
+out:
+	spin_unlock_irqrestore(hba->host->host_lock, flags);
+	return ret;
+}
+
 /**
  * ufshcd_uic_change_pwr_mode - Perform the UIC power mode chage
  *				using DME_SET primitives.
diff --git a/include/linux/phy/phy-qcom-ufs.h~HEAD b/include/linux/phy/phy-qcom-ufs.h~HEAD
new file mode 100644
index 000000000000..9d18e9f948e9
--- /dev/null
+++ b/include/linux/phy/phy-qcom-ufs.h~HEAD
@@ -0,0 +1,59 @@
+/*
+ * Copyright (c) 2013-2015, Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef PHY_QCOM_UFS_H_
+#define PHY_QCOM_UFS_H_
+
+#include "phy.h"
+
+/**
+ * ufs_qcom_phy_enable_ref_clk() - Enable the phy
+ * ref clock.
+ * @phy: reference to a generic phy
+ *
+ * returns 0 for success, and non-zero for error.
+ */
+int ufs_qcom_phy_enable_ref_clk(struct phy *phy);
+
+/**
+ * ufs_qcom_phy_disable_ref_clk() - Disable the phy
+ * ref clock.
+ * @phy: reference to a generic phy.
+ */
+void ufs_qcom_phy_disable_ref_clk(struct phy *phy);
+
+/**
+ * ufs_qcom_phy_enable_dev_ref_clk() - Enable the device
+ * ref clock.
+ * @phy: reference to a generic phy.
+ */
+void ufs_qcom_phy_enable_dev_ref_clk(struct phy *phy);
+
+/**
+ * ufs_qcom_phy_disable_dev_ref_clk() - Disable the device
+ * ref clock.
+ * @phy: reference to a generic phy.
+ */
+void ufs_qcom_phy_disable_dev_ref_clk(struct phy *phy);
+
+int ufs_qcom_phy_enable_iface_clk(struct phy *phy);
+void ufs_qcom_phy_disable_iface_clk(struct phy *phy);
+int ufs_qcom_phy_start_serdes(struct phy *phy);
+int ufs_qcom_phy_set_tx_lane_enable(struct phy *phy, u32 tx_lanes);
+int ufs_qcom_phy_calibrate_phy(struct phy *phy, bool is_rate_B);
+int ufs_qcom_phy_is_pcs_ready(struct phy *phy);
+void ufs_qcom_phy_save_controller_version(struct phy *phy,
+			u8 major, u16 minor, u16 step);
+
+#endif /* PHY_QCOM_UFS_H_ */
diff --git a/include/linux/scsi/ufs/ufshcd.h b/include/linux/scsi/ufs/ufshcd.h
index bb24bcb3bf30..9a35a4cd170a 100644
--- a/include/linux/scsi/ufs/ufshcd.h
+++ b/include/linux/scsi/ufs/ufshcd.h
@@ -771,6 +771,7 @@ int ufshcd_query_descriptor(struct ufs_hba *hba, enum query_opcode opcode,
 
 int ufshcd_hold(struct ufs_hba *hba, bool async);
 void ufshcd_release(struct ufs_hba *hba);
+int ufshcd_wait_for_doorbell_clr(struct ufs_hba *hba, u64 wait_timeout_us);
 
 /* Wrapper functions for safely calling variant operations */
 static inline const char *ufshcd_get_var_name(struct ufs_hba *hba)
@@ -875,5 +876,4 @@ static inline void ufshcd_vops_dbg_register_dump(struct ufs_hba *hba)
 	if (hba->vops && hba->vops->dbg_register_dump)
 		hba->vops->dbg_register_dump(hba);
 }
-
 #endif /* End of Header */