[PATCH v4 4/6] scsi: ufs: rework link start-up process

[Seungwon Jeon <tgih.jun@samsung.com>]

Link start-up requires long time with multiphase handshakes
between UFS host and device. This affects driver's probe time.
This patch let link start-up run asynchronously. Link start-up
will be executed at the end of prove separately.
Along with this change, the following is worked.

Defined completion time of uic command to avoid a permanent wait.
Added mutex to guarantee of uic command at a time.
Adapted some sequence of controller initialization after link statup
according to HCI standard.

Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org>
Tested-by: Maya Erez <merez@codeaurora.org>
---
Change in v4:
- Addressed late interrupt case (Sujit).
- Move print message in link startup (Maya).

 drivers/scsi/ufs/ufshcd.c |  295 ++++++++++++++++++++++++++++++--------------
 drivers/scsi/ufs/ufshcd.h |   10 +-
 2 files changed, 208 insertions(+), 97 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index e04c74e..8363b92 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -33,11 +33,15 @@
  * this program.
  */
 
+#include <linux/async.h>
+
 #include "ufshcd.h"
 
 #define UFSHCD_ENABLE_INTRS	(UTP_TRANSFER_REQ_COMPL |\
 				 UTP_TASK_REQ_COMPL |\
 				 UFSHCD_ERROR_MASK)
+/* UIC command timeout, unit: ms */
+#define UIC_CMD_TIMEOUT	500
 
 enum {
 	UFSHCD_MAX_CHANNEL	= 0,
@@ -401,24 +405,122 @@ static inline void ufshcd_hba_capabilities(struct ufs_hba *hba)
 }
 
 /**
- * ufshcd_send_uic_command - Send UIC commands to unipro layers
+ * ufshcd_ready_for_uic_cmd - Check if controller is ready
+ *                            to accept UIC commands
  * @hba: per adapter instance
- * @uic_command: UIC command
+ * Return true on success, else false
+ */
+static inline bool ufshcd_ready_for_uic_cmd(struct ufs_hba *hba)
+{
+	if (ufshcd_readl(hba, REG_CONTROLLER_STATUS) & UIC_COMMAND_READY)
+		return true;
+	else
+		return false;
+}
+
+/**
+ * ufshcd_dispatch_uic_cmd - Dispatch UIC commands to unipro layers
+ * @hba: per adapter instance
+ * @uic_cmd: UIC command
+ *
+ * Mutex must be held.
  */
 static inline void
-ufshcd_send_uic_command(struct ufs_hba *hba, struct uic_command *uic_cmnd)
+ufshcd_dispatch_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd)
 {
+	WARN_ON(hba->active_uic_cmd);
+
+	hba->active_uic_cmd = uic_cmd;
+
 	/* Write Args */
-	ufshcd_writel(hba, uic_cmnd->argument1, REG_UIC_COMMAND_ARG_1);
-	ufshcd_writel(hba, uic_cmnd->argument2, REG_UIC_COMMAND_ARG_2);
-	ufshcd_writel(hba, uic_cmnd->argument3, REG_UIC_COMMAND_ARG_3);
+	ufshcd_writel(hba, uic_cmd->argument1, REG_UIC_COMMAND_ARG_1);
+	ufshcd_writel(hba, uic_cmd->argument2, REG_UIC_COMMAND_ARG_2);
+	ufshcd_writel(hba, uic_cmd->argument3, REG_UIC_COMMAND_ARG_3);
 
 	/* Write UIC Cmd */
-	ufshcd_writel(hba, uic_cmnd->command & COMMAND_OPCODE_MASK,
+	ufshcd_writel(hba, uic_cmd->command & COMMAND_OPCODE_MASK,
 		      REG_UIC_COMMAND);
 }
 
 /**
+ * ufshcd_wait_for_uic_cmd - Wait complectioin of UIC command
+ * @hba: per adapter instance
+ * @uic_command: UIC command
+ *
+ * Must be called with mutex held.
+ * Returns 0 only if success.
+ */
+static int
+ufshcd_wait_for_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd)
+{
+	int ret;
+	unsigned long flags;
+
+	if (wait_for_completion_timeout(&uic_cmd->done,
+					msecs_to_jiffies(UIC_CMD_TIMEOUT)))
+		ret = uic_cmd->argument2 & MASK_UIC_COMMAND_RESULT;
+	else
+		ret = -ETIMEDOUT;
+
+	spin_lock_irqsave(hba->host->host_lock, flags);
+	hba->active_uic_cmd = NULL;
+	spin_unlock_irqrestore(hba->host->host_lock, flags);
+
+	return ret;
+}
+
+/**
+ * __ufshcd_send_uic_cmd - Send UIC commands and retrieve the result
+ * @hba: per adapter instance
+ * @uic_cmd: UIC command
+ *
+ * Identical to ufshcd_send_uic_cmd() expect mutex. Must be called
+ * with mutex held.
+ * Returns 0 only if success.
+ */
+static int
+__ufshcd_send_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd)
+{
+	int ret;
+	unsigned long flags;
+
+	if (!ufshcd_ready_for_uic_cmd(hba)) {
+		dev_err(hba->dev,
+			"Controller not ready to accept UIC commands\n");
+		return -EIO;
+	}
+
+	init_completion(&uic_cmd->done);
+
+	spin_lock_irqsave(hba->host->host_lock, flags);
+	ufshcd_dispatch_uic_cmd(hba, uic_cmd);
+	spin_unlock_irqrestore(hba->host->host_lock, flags);
+
+	ret = ufshcd_wait_for_uic_cmd(hba, uic_cmd);
+
+	return ret;
+}
+
+/**
+ * ufshcd_send_uic_cmd - Send UIC commands and retrieve the result
+ * @hba: per adapter instance
+ * @uic_cmd: UIC command
+ *
+ * Returns 0 only if success.
+ */
+static int
+ufshcd_send_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd)
+{
+	int ret;
+
+	mutex_lock(&hba->uic_cmd_mutex);
+	ret = __ufshcd_send_uic_cmd(hba, uic_cmd);
+	mutex_unlock(&hba->uic_cmd_mutex);
+
+	return ret;
+}
+
+/**
  * ufshcd_map_sg - Map scatter-gather list to prdt
  * @lrbp - pointer to local reference block
  *
@@ -962,34 +1064,16 @@ static void ufshcd_host_memory_configure(struct ufs_hba *hba)
  */
 static int ufshcd_dme_link_startup(struct ufs_hba *hba)
 {
-	struct uic_command *uic_cmd;
-	unsigned long flags;
-
-	/* check if controller is ready to accept UIC commands */
-	if ((ufshcd_readl(hba, REG_CONTROLLER_STATUS) &
-	    UIC_COMMAND_READY) == 0x0) {
-		dev_err(hba->dev,
-			"Controller not ready"
-			" to accept UIC commands\n");
-		return -EIO;
-	}
+	struct uic_command uic_cmd = {0};
+	int ret;
 
-	spin_lock_irqsave(hba->host->host_lock, flags);
+	uic_cmd.command = UIC_CMD_DME_LINK_STARTUP;
 
-	/* form UIC command */
-	uic_cmd = &hba->active_uic_cmd;
-	uic_cmd->command = UIC_CMD_DME_LINK_STARTUP;
-	uic_cmd->argument1 = 0;
-	uic_cmd->argument2 = 0;
-	uic_cmd->argument3 = 0;
-
-	/* enable UIC related interrupts */
-	ufshcd_enable_intr(hba, UIC_COMMAND_COMPL);
-
-	/* sending UIC commands to controller */
-	ufshcd_send_uic_command(hba, uic_cmd);
-	spin_unlock_irqrestore(hba->host->host_lock, flags);
-	return 0;
+	ret = ufshcd_send_uic_cmd(hba, &uic_cmd);
+	if (ret)
+		dev_err(hba->dev,
+			"dme-link-startup: error code %d\n", ret);
+	return ret;
 }
 
 /**
@@ -998,9 +1082,10 @@ static int ufshcd_dme_link_startup(struct ufs_hba *hba)
  *
  * To bring UFS host controller to operational state,
  * 1. Check if device is present
- * 2. Configure run-stop-registers
- * 3. Enable required interrupts
- * 4. Configure interrupt aggregation
+ * 2. Enable required interrupts
+ * 3. Configure interrupt aggregation
+ * 4. Program UTRL and UTMRL base addres
+ * 5. Configure run-stop-registers
  *
  * Returns 0 on success, non-zero value on failure
  */
@@ -1017,6 +1102,22 @@ static int ufshcd_make_hba_operational(struct ufs_hba *hba)
 		goto out;
 	}
 
+	/* Enable required interrupts */
+	ufshcd_enable_intr(hba, UFSHCD_ENABLE_INTRS);
+
+	/* Configure interrupt aggregation */
+	ufshcd_config_int_aggr(hba, INT_AGGR_CONFIG);
+
+	/* Configure UTRL and UTMRL base address registers */
+	ufshcd_writel(hba, lower_32_bits(hba->utrdl_dma_addr),
+			REG_UTP_TRANSFER_REQ_LIST_BASE_L);
+	ufshcd_writel(hba, upper_32_bits(hba->utrdl_dma_addr),
+			REG_UTP_TRANSFER_REQ_LIST_BASE_H);
+	ufshcd_writel(hba, lower_32_bits(hba->utmrdl_dma_addr),
+			REG_UTP_TASK_REQ_LIST_BASE_L);
+	ufshcd_writel(hba, upper_32_bits(hba->utmrdl_dma_addr),
+			REG_UTP_TASK_REQ_LIST_BASE_H);
+
 	/*
 	 * UCRDY, UTMRLDY and UTRLRDY bits must be 1
 	 * DEI, HEI bits must be 0
@@ -1030,17 +1131,11 @@ static int ufshcd_make_hba_operational(struct ufs_hba *hba)
 		goto out;
 	}
 
-	/* Enable required interrupts */
-	ufshcd_enable_intr(hba, UFSHCD_ENABLE_INTRS);
-
-	/* Configure interrupt aggregation */
-	ufshcd_config_int_aggr(hba, INT_AGGR_CONFIG);
-
 	if (hba->ufshcd_state == UFSHCD_STATE_RESET)
 		scsi_unblock_requests(hba->host);
 
 	hba->ufshcd_state = UFSHCD_STATE_OPERATIONAL;
-	scsi_scan_host(hba->host);
+
 out:
 	return err;
 }
@@ -1109,34 +1204,28 @@ static int ufshcd_hba_enable(struct ufs_hba *hba)
 }
 
 /**
- * ufshcd_initialize_hba - start the initialization process
+ * ufshcd_link_startup - Initialize unipro link startup
  * @hba: per adapter instance
  *
- * 1. Enable the controller via ufshcd_hba_enable.
- * 2. Program the Transfer Request List Address with the starting address of
- * UTRDL.
- * 3. Program the Task Management Request List Address with starting address
- * of UTMRDL.
- *
- * Returns 0 on success, non-zero value on failure.
+ * Returns 0 for success, non-zero in case of failure
  */
-static int ufshcd_initialize_hba(struct ufs_hba *hba)
+static int ufshcd_link_startup(struct ufs_hba *hba)
 {
-	if (ufshcd_hba_enable(hba))
-		return -EIO;
+	int ret;
 
-	/* Configure UTRL and UTMRL base address registers */
-	ufshcd_writel(hba, lower_32_bits(hba->utrdl_dma_addr),
-		      REG_UTP_TRANSFER_REQ_LIST_BASE_L);
-	ufshcd_writel(hba, upper_32_bits(hba->utrdl_dma_addr),
-		      REG_UTP_TRANSFER_REQ_LIST_BASE_H);
-	ufshcd_writel(hba, lower_32_bits(hba->utmrdl_dma_addr),
-		      REG_UTP_TASK_REQ_LIST_BASE_L);
-	ufshcd_writel(hba, upper_32_bits(hba->utmrdl_dma_addr),
-		      REG_UTP_TASK_REQ_LIST_BASE_H);
+	/* enable UIC related interrupts */
+	ufshcd_enable_intr(hba, UIC_COMMAND_COMPL);
 
-	/* Initialize unipro link startup procedure */
-	return ufshcd_dme_link_startup(hba);
+	ret = ufshcd_dme_link_startup(hba);
+	if (ret)
+		goto out;
+
+	ret = ufshcd_make_hba_operational(hba);
+
+out:
+	if (ret)
+		dev_err(hba->dev, "link startup failed %d\n", ret);
+	return ret;
 }
 
 /**
@@ -1176,12 +1265,19 @@ static int ufshcd_do_reset(struct ufs_hba *hba)
 	hba->outstanding_reqs = 0;
 	hba->outstanding_tasks = 0;
 
-	/* start the initialization process */
-	if (ufshcd_initialize_hba(hba)) {
+	/* Host controller enable */
+	if (ufshcd_hba_enable(hba)) {
 		dev_err(hba->dev,
 			"Reset: Controller initialization failed\n");
 		return FAILED;
 	}
+
+	if (ufshcd_link_startup(hba)) {
+		dev_err(hba->dev,
+			"Reset: Link start-up failed\n");
+		return FAILED;
+	}
+
 	return SUCCESS;
 }
 
@@ -1434,6 +1530,19 @@ ufshcd_transfer_rsp_status(struct ufs_hba *hba, struct ufshcd_lrb *lrbp)
 }
 
 /**
+ * ufshcd_uic_cmd_compl - handle completion of uic command
+ * @hba: per adapter instance
+ */
+static void ufshcd_uic_cmd_compl(struct ufs_hba *hba)
+{
+	if (hba->active_uic_cmd) {
+		hba->active_uic_cmd->argument2 |=
+			ufshcd_get_uic_cmd_result(hba);
+		complete(&hba->active_uic_cmd->done);
+	}
+}
+
+/**
  * ufshcd_transfer_req_compl - handle SCSI and query command completion
  * @hba: per adapter instance
  */
@@ -1473,28 +1582,6 @@ static void ufshcd_transfer_req_compl(struct ufs_hba *hba)
 }
 
 /**
- * ufshcd_uic_cc_handler - handle UIC command completion
- * @work: pointer to a work queue structure
- *
- * Returns 0 on success, non-zero value on failure
- */
-static void ufshcd_uic_cc_handler (struct work_struct *work)
-{
-	struct ufs_hba *hba;
-
-	hba = container_of(work, struct ufs_hba, uic_workq);
-
-	if ((hba->active_uic_cmd.command == UIC_CMD_DME_LINK_STARTUP) &&
-	    !(ufshcd_get_uic_cmd_result(hba))) {
-
-		if (ufshcd_make_hba_operational(hba))
-			dev_err(hba->dev,
-				"cc: hba not operational state\n");
-		return;
-	}
-}
-
-/**
  * ufshcd_fatal_err_handler - handle fatal errors
  * @hba: per adapter instance
  */
@@ -1555,7 +1642,7 @@ static void ufshcd_sl_intr(struct ufs_hba *hba, u32 intr_status)
 		ufshcd_err_handler(hba);
 
 	if (intr_status & UIC_COMMAND_COMPL)
-		schedule_work(&hba->uic_workq);
+		ufshcd_uic_cmd_compl(hba);
 
 	if (intr_status & UTP_TASK_REQ_COMPL)
 		ufshcd_tmc_handler(hba);
@@ -1778,6 +1865,21 @@ out:
 	return err;
 }
 
+/**
+ * ufshcd_async_scan - asynchronous execution for link startup
+ * @data: data pointer to pass to this function
+ * @cookie: cookie data
+ */
+static void ufshcd_async_scan(void *data, async_cookie_t cookie)
+{
+	struct ufs_hba *hba = (struct ufs_hba *)data;
+	int ret;
+
+	ret = ufshcd_link_startup(hba);
+	if (!ret)
+		scsi_scan_host(hba->host);
+}
+
 static struct scsi_host_template ufshcd_driver_template = {
 	.module			= THIS_MODULE,
 	.name			= UFSHCD,
@@ -1939,12 +2041,14 @@ int ufshcd_init(struct device *dev, struct ufs_hba **hba_handle,
 	init_waitqueue_head(&hba->ufshcd_tm_wait_queue);
 
 	/* Initialize work queues */
-	INIT_WORK(&hba->uic_workq, ufshcd_uic_cc_handler);
 	INIT_WORK(&hba->feh_workq, ufshcd_fatal_err_handler);
 
 	/* Initialize mutex for query requests */
 	mutex_init(&hba->query.lock_ufs_query);
 
+	/* Initialize UIC command mutex */
+	mutex_init(&hba->uic_cmd_mutex);
+
 	/* IRQ registration */
 	err = request_irq(irq, ufshcd_intr, IRQF_SHARED, UFSHCD, hba);
 	if (err) {
@@ -1965,14 +2069,17 @@ int ufshcd_init(struct device *dev, struct ufs_hba **hba_handle,
 		goto out_free_irq;
 	}
 
-	/* Initialization routine */
-	err = ufshcd_initialize_hba(hba);
+	/* Host controller enable */
+	err = ufshcd_hba_enable(hba);
 	if (err) {
-		dev_err(hba->dev, "Initialization failed\n");
+		dev_err(hba->dev, "Host controller enable failed\n");
 		goto out_remove_scsi_host;
 	}
+
 	*hba_handle = hba;
 
+	async_schedule(ufshcd_async_scan, hba);
+
 	return 0;
 
 out_remove_scsi_host:
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index d98e046..974bd07 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -51,6 +51,7 @@
 #include <linux/bitops.h>
 #include <linux/pm_runtime.h>
 #include <linux/clk.h>
+#include <linux/completion.h>
 
 #include <asm/irq.h>
 #include <asm/byteorder.h>
@@ -76,6 +77,7 @@
  * @argument3: UIC command argument 3
  * @cmd_active: Indicate if UIC command is outstanding
  * @result: UIC command result
+ * @done: UIC command completion
  */
 struct uic_command {
 	u32 command;
@@ -84,6 +86,7 @@ struct uic_command {
 	u32 argument3;
 	int cmd_active;
 	int result;
+	struct completion done;
 };
 
 /**
@@ -150,11 +153,11 @@ struct ufs_query {
  * @ufs_version: UFS Version to which controller complies
  * @irq: Irq number of the controller
  * @active_uic_cmd: handle of active UIC command
+ * @uic_cmd_mutex: mutex for uic command
  * @ufshcd_tm_wait_queue: wait queue for task management
  * @tm_condition: condition variable for task management
  * @ufshcd_state: UFSHCD states
  * @intr_mask: Interrupt Mask Bits
- * @uic_workq: Work queue for UIC completion handling
  * @feh_workq: Work queue for fatal controller error handling
  * @errors: HBA errors
  * @query: query request information
@@ -186,7 +189,9 @@ struct ufs_hba {
 	u32 ufs_version;
 	unsigned int irq;
 
-	struct uic_command active_uic_cmd;
+	struct uic_command *active_uic_cmd;
+	struct mutex uic_cmd_mutex;
+
 	wait_queue_head_t ufshcd_tm_wait_queue;
 	unsigned long tm_condition;
 
@@ -194,7 +199,6 @@ struct ufs_hba {
 	u32 intr_mask;
 
 	/* Work Queues */
-	struct work_struct uic_workq;
 	struct work_struct feh_workq;
 
 	/* HBA Errors */
-- 
1.7.0.4