Re: [PATCH 4/5] scsi: ufs: rework link start-up process

Sujit Reddy Thumma <sthumma@xxxxxxxxxxxxxx> · Thu, 25 Apr 2013 10:35:03 +0530

On 4/24/2013 9:36 PM, Seungwon Jeon wrote:
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.
And completion time of uic command is defined to avoid a
permanent wait.

I have similar patch posted few days back "scsi: ufs: Generalize UFS 
Interconnect Layer (UIC) command support" which does a bit more (mutex, 
error handling) than what is done here. Can that be used/improved?


Signed-off-by: Seungwon Jeon <tgih.jun@xxxxxxxxxxx>
---
  drivers/scsi/ufs/ufshcd.c |  114 +++++++++++++++++++++++++++++++++-----------
  drivers/scsi/ufs/ufshcd.h |    6 ++-
  2 files changed, 89 insertions(+), 31 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index efe2256..76ff332 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -38,6 +38,7 @@
  #define UFSHCD_ENABLE_INTRS	(UTP_TRANSFER_REQ_COMPL |\
  				 UTP_TASK_REQ_COMPL |\
  				 UFSHCD_ERROR_MASK)
+#define UIC_CMD_TIMEOUT	100

  enum {
  	UFSHCD_MAX_CHANNEL	= 0,
@@ -357,13 +358,15 @@ static inline void ufshcd_hba_capabilities(struct ufs_hba *hba)
  }

  /**
- * ufshcd_send_uic_command - Send UIC commands to unipro layers
+ * ufshcd_dispatch_uic_cmd - Dispatch UIC commands to unipro layers
   * @hba: per adapter instance
   * @uic_command: UIC command
   */
  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_cmnd)
  {
+	init_completion(&uic_cmnd->done);
+
  	/* Write Args */
  	ufshcd_writel(hba, REG_UIC_COMMAND_ARG_1, uic_cmnd->argument1);
  	ufshcd_writel(hba, REG_UIC_COMMAND_ARG_2, uic_cmnd->argument2);
@@ -375,6 +378,45 @@ ufshcd_send_uic_command(struct ufs_hba *hba, struct uic_command *uic_cmnd)
  }

  /**
+ * ufshcd_wait_for_uic_cmd - Wait complectioin of UIC command
+ * @hba: per adapter instance
+ * @uic_command: UIC command
+ *
+ * Returns 0 only if success.
+ */
+static int ufshcd_wait_for_uic_cmd(struct ufs_hba *hba)
+{
+	struct uic_command *uic_cmd = &hba->active_uic_cmd;
+	int ret;
+
+	if (wait_for_completion_timeout(&uic_cmd->done,
+					msecs_to_jiffies(UIC_CMD_TIMEOUT)))
+		ret = ufshcd_get_uic_cmd_result(hba);
+	else
+		ret = -ETIMEDOUT;
+
+	return ret;
+}
+
+/**
+ * ufshcd_ready_uic_cmd - Check if controller is ready
+ *                        to accept UIC commands
+ * @hba: per adapter instance
+ * Return true on success, else false
+ */
+static inline bool ufshcd_ready_uic_cmd(struct ufs_hba *hba)
+{
+	if (ufshcd_readl(hba, REG_CONTROLLER_STATUS) & UIC_COMMAND_READY) {
+		return true;
+	} else {
+		dev_err(hba->dev,
+				"Controller not ready"
+				" to accept UIC commands\n");
+		return false;
+	}
+}
+
+/**
   * ufshcd_map_sg - Map scatter-gather list to prdt
   * @lrbp - pointer to local reference block
   *
@@ -735,15 +777,10 @@ static int ufshcd_dme_link_startup(struct ufs_hba *hba)
  {
  	struct uic_command *uic_cmd;
  	unsigned long flags;
+	int ret;

-	/* 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");
+	if (!ufshcd_ready_uic_cmd(hba))
  		return -EIO;
-	}

  	spin_lock_irqsave(hba->host->host_lock, flags);

@@ -754,13 +791,16 @@ static int ufshcd_dme_link_startup(struct ufs_hba *hba)
  	uic_cmd->argument2 = 0;
  	uic_cmd->argument3 = 0;

-	/* enable UIC related interrupts */
-	ufshcd_enable_intr(hba, UIC_COMMAND_COMPL);
+	/* Dispatching UIC commands to controller */
+	ufshcd_dispatch_uic_cmd(hba, uic_cmd);

-	/* sending UIC commands to controller */
-	ufshcd_send_uic_command(hba, uic_cmd);
  	spin_unlock_irqrestore(hba->host->host_lock, flags);
-	return 0;
+
+	ret = ufshcd_wait_for_uic_cmd(hba);
+	if (ret)
+		dev_err(hba->dev, "link startup: error code %d returned\n", ret);
+
+	return ret;
  }

  /**
@@ -898,6 +938,9 @@ static int ufshcd_initialize_hba(struct ufs_hba *hba)
  	if (ufshcd_hba_enable(hba))
  		return -EIO;

+	/* enable UIC related interrupts */
+	ufshcd_enable_intr(hba, UIC_COMMAND_COMPL | UIC_ERROR);
+
  	/* Configure UTRL and UTMRL base address registers */
  	ufshcd_writel(hba, REG_UTP_TRANSFER_REQ_LIST_BASE_L,
  		      lower_32_bits(hba->utrdl_dma_addr));
@@ -909,7 +952,9 @@ static int ufshcd_initialize_hba(struct ufs_hba *hba)
  		      upper_32_bits(hba->utmrdl_dma_addr));

  	/* Initialize unipro link startup procedure */
-	return ufshcd_dme_link_startup(hba);
+	schedule_work(&hba->link_startup_wq);
+
+	return 0;
  }

  /**
@@ -1186,6 +1231,16 @@ 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, u32 intr_status)
+{
+	if (intr_status & UIC_COMMAND_COMPL)
+		complete(&hba->active_uic_cmd.done);
+}
+
+/**
   * ufshcd_transfer_req_compl - handle SCSI and query command completion
   * @hba: per adapter instance
   */
@@ -1225,25 +1280,26 @@ static void ufshcd_transfer_req_compl(struct ufs_hba *hba)
  }

  /**
- * ufshcd_uic_cc_handler - handle UIC command completion
+ * ufshcd_link_startup - link initialization
   * @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)
+static void ufshcd_link_startup(struct work_struct *work)
  {
  	struct ufs_hba *hba;
+	int ret;

-	hba = container_of(work, struct ufs_hba, uic_workq);
+	hba = container_of(work, struct ufs_hba, link_startup_wq);

-	if ((hba->active_uic_cmd.command == UIC_CMD_DME_LINK_STARTUP) &&
-	    !(ufshcd_get_uic_cmd_result(hba))) {
+	ret = ufshcd_dme_link_startup(hba);
+	if (ret)
+		goto out;

-		if (ufshcd_make_hba_operational(hba))
-			dev_err(hba->dev,
-				"cc: hba not operational state\n");
-		return;
-	}
+	ret = ufshcd_make_hba_operational(hba);
+	if (ret)
+		goto out;
+	return;
+out:
+	dev_err(hba->dev, "link startup failed %d\n", ret);
  }

  /**
@@ -1307,7 +1363,7 @@ 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, intr_status);

  	if (intr_status & UTP_TASK_REQ_COMPL)
  		ufshcd_tmc_handler(hba);
@@ -1694,7 +1750,7 @@ 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->link_startup_wq, ufshcd_link_startup);
  	INIT_WORK(&hba->feh_workq, ufshcd_fatal_err_handler);

  	/* IRQ registration */
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index 87d5a94..2fb4d94 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>
@@ -83,6 +84,7 @@ struct uic_command {
  	u32 argument3;
  	int cmd_active;
  	int result;
+	struct completion done;
  };

  /**
@@ -140,7 +142,7 @@ struct ufshcd_lrb {
   * @tm_condition: condition variable for task management
   * @ufshcd_state: UFSHCD states
   * @intr_mask: Interrupt Mask Bits
- * @uic_workq: Work queue for UIC completion handling
+ * @link_startup_wq: Work queue for link start-up
   * @feh_workq: Work queue for fatal controller error handling
   * @errors: HBA errors
   */
@@ -179,7 +181,7 @@ struct ufs_hba {
  	u32 intr_mask;

  	/* Work Queues */
-	struct work_struct uic_workq;
+	struct work_struct link_startup_wq;
  	struct work_struct feh_workq;

  	/* HBA Errors */


--
Regards,
Sujit
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