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

Seungwon Jeon
2013-04-24T16:06:36Z

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.

Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
---
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 */
--
1.7.0.4