[SCSI] ufs: rework link start-up process

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>
Signed-off-by: Santosh Y <santoshsy@gmail.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

2 files changed, 208 insertions, 97 deletions

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 2e0248302e8d..48a76459a5c9 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,
@@ -349,24 +353,122 @@ 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
  *
@@ -725,34 +827,16 @@ 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;
+        struct uic_command uic_cmd = {0};
+        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");
-                return -EIO;
-        }
+        uic_cmd.command = UIC_CMD_DME_LINK_STARTUP;
 
-        spin_lock_irqsave(hba->host->host_lock, flags);
-
-        /* 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;
 }
 
 /**
@@ -761,9 +845,10 @@ 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
  */
@@ -780,6 +865,22 @@ 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
@@ -793,17 +894,11 @@ 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;
 }
@@ -872,34 +967,28 @@ 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);
+
+        ret = ufshcd_dme_link_startup(hba);
+        if (ret)
+                goto out;
+
+        ret = ufshcd_make_hba_operational(hba);
 
-        /* Initialize unipro link startup procedure */
-        return ufshcd_dme_link_startup(hba);
+out:
+        if (ret)
+                dev_err(hba->dev, "link startup failed %d\n", ret);
+        return ret;
 }
 
 /**
@@ -939,12 +1028,19 @@ 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;
 }
 
@@ -1176,6 +1272,19 @@ 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
  */
@@ -1215,28 +1324,6 @@ 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
  */
@@ -1297,7 +1384,7 @@ 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);
@@ -1520,6 +1607,21 @@ 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,
@@ -1681,9 +1783,11 @@ 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 UIC command mutex */
+        mutex_init(&hba->uic_cmd_mutex);
+
         /* IRQ registration */
         err = request_irq(irq, ufshcd_intr, IRQF_SHARED, UFSHCD, hba);
         if (err) {
@@ -1704,14 +1808,17 @@ 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 4213600b89d6..49590ee07acc 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>
@@ -75,6 +76,7 @@
  * @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;
@@ -83,6 +85,7 @@ struct uic_command {
         u32 argument3;
         int cmd_active;
         int result;
+        struct completion done;
 };
 
 /**
@@ -136,11 +139,11 @@ struct ufshcd_lrb {
  * @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
  */
@@ -171,7 +174,9 @@ 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;
 
@@ -179,7 +184,6 @@ struct ufs_hba {
         u32 intr_mask;
 
         /* Work Queues */
-        struct work_struct uic_workq;
         struct work_struct feh_workq;
 
         /* HBA Errors */