scsi: ufs: Change power mode at run-time via debug-fs

Add 'power_mode' entry to UFS debug-fs to allow query of current
power mode status and changing the power mode by writing to the
entry a string in the format 'GGLLMM' where:
G - selected gear
L - number of lanes
M - power mode
    (1=fast mode, 2=slow mode, 4=fast-auto mode, 5=slow-auto mode)
First letter is for RX, second is for TX.

Change-Id: Ia48cb2719bb11e66bca923c5f4647a33cbd6c43e
Signed-off-by: Gilad Broner <gbroner@codeaurora.org>
[gbroner@codeaurora.org: fix merge conflicts]
Signed-off-by: Gilad Broner <gbroner@codeaurora.org>
[subhashj@codeaurora.org: resolved merge conflicts and compilation error]
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
[venkatg@codeaurora.org: resolved trivial merge conflicts]
Signed-off-by: Venkat Gopalakrishnan <venkatg@codeaurora.org>

drivers/scsi/ufs/debugfs.c

@@ -19,6 +19,7 @@
 
 #include <linux/random.h>
 #include "debugfs.h"
+#include "unipro.h"
 
 enum field_width {
 	BYTE	= 1,
@@ -599,6 +600,123 @@ static const struct file_operations ufsdbg_dump_device_desc = {
 	.read		= seq_read,
 };
 
+static int ufsdbg_power_mode_show(struct seq_file *file, void *data)
+{
+	struct ufs_hba *hba = (struct ufs_hba *)file->private;
+	char *names[] = {
+		"INVALID MODE",
+		"FAST MODE",
+		"SLOW MODE",
+		"INVALID MODE",
+		"FASTAUTO MODE",
+		"SLOWAUTO MODE",
+		"INVALID MODE",
+	};
+
+	/* Print current status */
+	seq_puts(file, "UFS current power mode [RX, TX]:");
+	seq_printf(file, "gear=[%d,%d], lane=[%d,%d], pwr=[%s,%s], rate = %c",
+		 hba->pwr_info.gear_rx, hba->pwr_info.gear_tx,
+		 hba->pwr_info.lane_rx, hba->pwr_info.lane_tx,
+		 names[hba->pwr_info.pwr_rx],
+		 names[hba->pwr_info.pwr_tx],
+		 hba->pwr_info.hs_rate == PA_HS_MODE_B ? 'B' : 'A');
+	seq_puts(file, "\n\n");
+
+	/* Print usage */
+	seq_puts(file,
+		"To change power mode write 'GGLLMM' where:\n"
+		"G - selected gear\n"
+		"L - number of lanes\n"
+		"M - power mode:\n"
+		"\t1 = fast mode\n"
+		"\t2 = slow mode\n"
+		"\t4 = fast-auto mode\n"
+		"\t5 = slow-auto mode\n"
+		"first letter is for RX, second letter is for TX.\n\n");
+
+	return 0;
+}
+
+static bool ufsdbg_power_mode_validate(struct ufs_pa_layer_attr *pwr_mode)
+{
+	if (pwr_mode->gear_rx < UFS_PWM_G1 || pwr_mode->gear_rx > UFS_PWM_G7 ||
+		pwr_mode->gear_tx < UFS_PWM_G1 || pwr_mode->gear_tx > UFS_PWM_G7
+		|| pwr_mode->lane_rx < 1 || pwr_mode->lane_rx > 2 ||
+		pwr_mode->lane_tx < 1 || pwr_mode->lane_tx > 2 ||
+		(pwr_mode->pwr_rx != FAST_MODE &&
+		pwr_mode->pwr_rx != SLOW_MODE &&
+		pwr_mode->pwr_rx != FASTAUTO_MODE &&
+		pwr_mode->pwr_rx != SLOWAUTO_MODE) ||
+		(pwr_mode->pwr_tx != FAST_MODE &&
+		pwr_mode->pwr_tx != SLOW_MODE &&
+		pwr_mode->pwr_tx != FASTAUTO_MODE &&
+		pwr_mode->pwr_tx != SLOWAUTO_MODE))
+		return false;
+
+	return true;
+}
+
+static ssize_t ufsdbg_power_mode_write(struct file *file,
+				const char __user *ubuf, size_t cnt,
+				loff_t *ppos)
+{
+	struct ufs_hba *hba = file->f_mapping->host->i_private;
+	struct ufs_pa_layer_attr pwr_mode;
+	char pwr_mode_str[BUFF_LINE_CAPACITY] = {0};
+	loff_t buff_pos = 0;
+	int ret;
+	int idx = 0;
+
+	ret = simple_write_to_buffer(pwr_mode_str, BUFF_LINE_CAPACITY,
+		&buff_pos, ubuf, cnt);
+
+	pwr_mode.gear_rx = pwr_mode_str[idx++] - '0';
+	pwr_mode.gear_tx = pwr_mode_str[idx++] - '0';
+	pwr_mode.lane_rx = pwr_mode_str[idx++] - '0';
+	pwr_mode.lane_tx = pwr_mode_str[idx++] - '0';
+	pwr_mode.pwr_rx = pwr_mode_str[idx++] - '0';
+	pwr_mode.pwr_tx = pwr_mode_str[idx++] - '0';
+	/*
+	 * Switching between rates is not currently supported so use the
+	 * current rate.
+	 * TODO: add rate switching if and when it is supported in the future
+	 */
+	pwr_mode.hs_rate = hba->pwr_info.hs_rate;
+
+	/* Validate user input */
+	if (!ufsdbg_power_mode_validate(&pwr_mode))
+		return -EINVAL;
+
+	pr_debug(
+		"%s: new power mode requested [RX,TX]: Gear=[%d,%d] Lanes=[%d,%d], Mode=[%d,%d]\n",
+		__func__, pwr_mode.gear_rx, pwr_mode.gear_tx, pwr_mode.lane_rx,
+		pwr_mode.lane_tx, pwr_mode.pwr_rx, pwr_mode.pwr_tx);
+
+	ret = ufshcd_config_pwr_mode(hba, &pwr_mode);
+	if (ret == -EBUSY)
+		dev_err(hba->dev,
+			"%s: ufshcd_config_pwr_mode failed: system is busy, try again\n",
+			__func__);
+	else if (ret)
+		dev_err(hba->dev,
+			"%s: ufshcd_config_pwr_mode failed, ret=%d\n",
+			__func__, ret);
+
+	return cnt;
+}
+
+static int ufsdbg_power_mode_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, ufsdbg_power_mode_show, inode->i_private);
+}
+
+static const struct file_operations ufsdbg_power_mode_desc = {
+	.open		= ufsdbg_power_mode_open,
+	.read		= seq_read,
+	.write		= ufsdbg_power_mode_write,
+};
+
 void ufsdbg_add_debugfs(struct ufs_hba *hba)
 {
 	if (!hba) {
@@ -672,6 +790,16 @@ void ufsdbg_add_debugfs(struct ufs_hba *hba)
 		goto err;
 	}
 
+	hba->debugfs_files.power_mode =
+		debugfs_create_file("power_mode", S_IRUSR | S_IWUSR,
+				    hba->debugfs_files.debugfs_root, hba,
+				    &ufsdbg_power_mode_desc);
+	if (!hba->debugfs_files.power_mode) {
+		dev_err(hba->dev,
+			"%s:  NULL power_mode_desc file, exiting", __func__);
+		goto err;
+	}
+
 	ufsdbg_setup_fault_injection(hba);
 
 	return;

drivers/scsi/ufs/ufshcd.c

@@ -110,6 +110,9 @@
 /* UIC command timeout, unit: ms */
 #define UIC_CMD_TIMEOUT	500
 
+/* Retries waiting for doorbells to clear */
+#define POWER_MODE_RETRIES	10
+
 /* NOP OUT retries waiting for NOP IN response */
 #define NOP_OUT_RETRIES    10
 /* Timeout after 30 msecs if NOP OUT hangs without response */
@@ -278,8 +281,6 @@ static int ufshcd_host_reset_and_restore(struct ufs_hba *hba);
 static void ufshcd_resume_clkscaling(struct ufs_hba *hba);
 static void ufshcd_suspend_clkscaling(struct ufs_hba *hba);
 static irqreturn_t ufshcd_intr(int irq, void *__hba);
-static int ufshcd_config_pwr_mode(struct ufs_hba *hba,
-		struct ufs_pa_layer_attr *desired_pwr_mode);
 static int ufshcd_change_power_mode(struct ufs_hba *hba,
 			     struct ufs_pa_layer_attr *pwr_mode);
 
@@ -1259,6 +1260,7 @@ ufshcd_send_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd)
 	unsigned long flags;
 
 	ufshcd_hold(hba, false);
+	pm_runtime_get_sync(hba->dev);
 	mutex_lock(&hba->uic_cmd_mutex);
 	ufshcd_add_delay_before_dme_cmd(hba);
 
@@ -1269,7 +1271,7 @@ ufshcd_send_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd)
 		ret = ufshcd_wait_for_uic_cmd(hba, uic_cmd);
 
 	mutex_unlock(&hba->uic_cmd_mutex);
-
+	pm_runtime_put_sync(hba->dev);
 	ufshcd_release(hba);
 	return ret;
 }
@@ -2709,14 +2711,45 @@ 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;
 
 	ufshcd_hold(hba, false);
+	pm_runtime_get_sync(hba->dev);
 	mutex_lock(&hba->uic_cmd_mutex);
 	init_completion(&uic_async_done);
 	ufshcd_add_delay_before_dme_cmd(hba);
 
-	spin_lock_irqsave(hba->host->host_lock, flags);
+	/*
+	 * 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;
+	}
+
 	hba->uic_async_done = &uic_async_done;
+
 	ret = __ufshcd_send_uic_cmd(hba, cmd);
 	spin_unlock_irqrestore(hba->host->host_lock, flags);
 	if (ret) {
@@ -2754,7 +2787,7 @@ out:
 	hba->uic_async_done = NULL;
 	spin_unlock_irqrestore(hba->host->host_lock, flags);
 	mutex_unlock(&hba->uic_cmd_mutex);
-
+	pm_runtime_put_sync(hba->dev);
 	ufshcd_release(hba);
 	return ret;
 }
@@ -2981,7 +3014,7 @@ static int ufshcd_change_power_mode(struct ufs_hba *hba,
  * @hba: per-adapter instance
  * @desired_pwr_mode: desired power configuration
  */
-static int ufshcd_config_pwr_mode(struct ufs_hba *hba,
+int ufshcd_config_pwr_mode(struct ufs_hba *hba,
 		struct ufs_pa_layer_attr *desired_pwr_mode)
 {
 	struct ufs_pa_layer_attr final_params = { 0 };

drivers/scsi/ufs/ufshcd.h

@@ -377,6 +377,7 @@ struct debugfs_files {
 	struct dentry *show_hba;
 	struct dentry *host_regs;
 	struct dentry *dump_dev_desc;
+	struct dentry *power_mode;
 #ifdef CONFIG_UFS_FAULT_INJECTION
 	struct fault_attr fail_attr;
 #endif
@@ -717,6 +718,8 @@ extern int ufshcd_dme_set_attr(struct ufs_hba *hba, u32 attr_sel,
 			       u8 attr_set, u32 mib_val, u8 peer);
 extern int ufshcd_dme_get_attr(struct ufs_hba *hba, u32 attr_sel,
 			       u32 *mib_val, u8 peer);
+extern int ufshcd_config_pwr_mode(struct ufs_hba *hba,
+		struct ufs_pa_layer_attr *desired_pwr_mode);
 
 /* UIC command interfaces for DME primitives */
 #define DME_LOCAL	0