[PATCH] shpchp: fix improper wait for command completion

Current SHPCHP driver uses msleep_interruptible() function to wait for
a command completion event. But I think this would cause an unnecessary
long wait until timeout, if command completion interrupt came before
task state was changed to TASK_INTERRUPTIBLE. This patch fixes this
issue. With this patch, command completion becomes faster as follows:

o Without this patch

	# time echo 1 > power

	real    0m4.708s
	user    0m0.000s
	sys     0m0.524s

o With this patch

	# time echo 1 > power

	real    0m2.221s
	user    0m0.000s
	sys     0m0.532s

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 27 insertions, 37 deletions

diff --git a/drivers/pci/hotplug/shpchp.h b/drivers/pci/hotplug/shpchp.h
index 55b0cd15f348..ce0e9b6ce833 100644
--- a/drivers/pci/hotplug/shpchp.h
+++ b/drivers/pci/hotplug/shpchp.h
@@ -101,6 +101,7 @@ struct controller {
         u32 cap_offset;
         unsigned long mmio_base;
         unsigned long mmio_size;
+        volatile int cmd_busy;
 };
 
 struct hotplug_params {
diff --git a/drivers/pci/hotplug/shpchp_ctrl.c b/drivers/pci/hotplug/shpchp_ctrl.c
index 58619359ad08..25ccb0e47593 100644
--- a/drivers/pci/hotplug/shpchp_ctrl.c
+++ b/drivers/pci/hotplug/shpchp_ctrl.c
@@ -248,7 +248,6 @@ static int change_bus_speed(struct controller *ctrl, struct slot *p_slot,
                 up(&ctrl->crit_sect);
                 return WRONG_BUS_FREQUENCY;
         }
-        wait_for_ctrl_irq (ctrl);
                 
         if ((rc = p_slot->hpc_ops->check_cmd_status(ctrl))) {
                 err("%s: Can't set bus speed/mode in the case of adapter & bus mismatch\n",
@@ -330,9 +329,6 @@ static int board_added(struct slot *p_slot)
                 up(&ctrl->crit_sect);
                 return -1;
         }
-                        
-        /* Wait for the command to complete */
-        wait_for_ctrl_irq (ctrl);
         
         rc = p_slot->hpc_ops->check_cmd_status(ctrl);
         if (rc) {
@@ -352,7 +348,6 @@ static int board_added(struct slot *p_slot)
                         up(&ctrl->crit_sect);
                         return WRONG_BUS_FREQUENCY;
                 }
-                wait_for_ctrl_irq (ctrl);
                 
                 if ((rc = p_slot->hpc_ops->check_cmd_status(ctrl))) {
                         err("%s: Can't set bus speed/mode in the case of adapter & bus mismatch\n",
@@ -367,7 +362,6 @@ static int board_added(struct slot *p_slot)
                         up(&ctrl->crit_sect);
                         return rc;
                 }
-                wait_for_ctrl_irq (ctrl);
 
                 if ((rc = p_slot->hpc_ops->check_cmd_status(ctrl))) {
                         err("%s: Failed to enable slot, error code(%d)\n", __FUNCTION__, rc);
@@ -494,7 +488,6 @@ static int board_added(struct slot *p_slot)
                 up(&ctrl->crit_sect);
                 return rc;
         }
-        wait_for_ctrl_irq (ctrl);
 
         if ((rc = p_slot->hpc_ops->check_cmd_status(ctrl))) {
                 err("%s: Failed to enable slot, error code(%d)\n", __FUNCTION__, rc);
@@ -532,9 +525,6 @@ static int board_added(struct slot *p_slot)
 
         p_slot->hpc_ops->green_led_on(p_slot);
 
-        /* Wait for the command to complete */
-        wait_for_ctrl_irq (ctrl);
-
         /* Done with exclusive hardware access */
         up(&ctrl->crit_sect);
 
@@ -552,8 +542,6 @@ err_exit:
                 up(&ctrl->crit_sect);
                 return rc;
         }
-        /* Wait for the command to complete */
-        wait_for_ctrl_irq (ctrl);
 
         rc = p_slot->hpc_ops->check_cmd_status(ctrl);
         if (rc) {
@@ -603,8 +591,6 @@ static int remove_board(struct slot *p_slot)
                 up(&ctrl->crit_sect);
                 return rc;
         }
-        /* Wait for the command to complete */
-        wait_for_ctrl_irq (ctrl);
 
         rc = p_slot->hpc_ops->check_cmd_status(ctrl);
         if (rc) {
@@ -621,8 +607,6 @@ static int remove_board(struct slot *p_slot)
                 up(&ctrl->crit_sect);
                 return rc;
         }
-        /* Wait for the command to complete */
-        wait_for_ctrl_irq (ctrl);
 
         /* Done with exclusive hardware access */
         up(&ctrl->crit_sect);
@@ -676,9 +660,6 @@ static void shpchp_pushbutton_thread (unsigned long slot)
 
                         p_slot->hpc_ops->green_led_off(p_slot);
 
-                        /* Wait for the command to complete */
-                        wait_for_ctrl_irq (p_slot->ctrl);
-
                         /* Done with exclusive hardware access */
                         up(&p_slot->ctrl->crit_sect);
                 }
@@ -790,14 +771,9 @@ static void interrupt_event_handler(struct controller *ctrl)
                                                 down(&ctrl->crit_sect);
 
                                                 p_slot->hpc_ops->green_led_on(p_slot);
-                                                /* Wait for the command to complete */
-                                                wait_for_ctrl_irq (ctrl);
 
                                                 p_slot->hpc_ops->set_attention_status(p_slot, 0);
 
-                                                /* Wait for the command to complete */
-                                                wait_for_ctrl_irq (ctrl);
-
                                                 /* Done with exclusive hardware access */
                                                 up(&ctrl->crit_sect);
                                                 break;
@@ -806,12 +782,8 @@ static void interrupt_event_handler(struct controller *ctrl)
                                                 down(&ctrl->crit_sect);
 
                                                 p_slot->hpc_ops->green_led_off(p_slot);
-                                                /* Wait for the command to complete */
-                                                wait_for_ctrl_irq (ctrl);
 
                                                 p_slot->hpc_ops->set_attention_status(p_slot, 0);
-                                                /* Wait for the command to complete */
-                                                wait_for_ctrl_irq (ctrl);
 
                                                 /* Done with exclusive hardware access */
                                                 up(&ctrl->crit_sect);
@@ -845,14 +817,9 @@ static void interrupt_event_handler(struct controller *ctrl)
 
                                         /* blink green LED and turn off amber */
                                         p_slot->hpc_ops->green_led_blink(p_slot);
-                                        /* Wait for the command to complete */
-                                        wait_for_ctrl_irq (ctrl);
                                         
                                         p_slot->hpc_ops->set_attention_status(p_slot, 0);
 
-                                        /* Wait for the command to complete */
-                                        wait_for_ctrl_irq (ctrl);
-
                                         /* Done with exclusive hardware access */
                                         up(&ctrl->crit_sect);
 
@@ -870,12 +837,8 @@ static void interrupt_event_handler(struct controller *ctrl)
                                         down(&ctrl->crit_sect);
 
                                         p_slot->hpc_ops->set_attention_status(p_slot, 1);
-                                        /* Wait for the command to complete */
-                                        wait_for_ctrl_irq (ctrl);
                                         
                                         p_slot->hpc_ops->green_led_off(p_slot);
-                                        /* Wait for the command to complete */
-                                        wait_for_ctrl_irq (ctrl);
 
                                         /* Done with exclusive hardware access */
                                         up(&ctrl->crit_sect);
diff --git a/drivers/pci/hotplug/shpchp_hpc.c b/drivers/pci/hotplug/shpchp_hpc.c
index f25e11645071..b4226ff3a854 100644
--- a/drivers/pci/hotplug/shpchp_hpc.c
+++ b/drivers/pci/hotplug/shpchp_hpc.c
@@ -275,6 +275,25 @@ static void start_int_poll_timer(struct php_ctlr_state_s *php_ctlr, int seconds)
         return;
 }
 
+static inline int shpc_wait_cmd(struct controller *ctrl)
+{
+        int retval = 0;
+        unsigned int timeout_msec = shpchp_poll_mode ? 2000 : 1000;
+        unsigned long timeout = msecs_to_jiffies(timeout_msec);
+        int rc = wait_event_interruptible_timeout(ctrl->queue,
+                                                  !ctrl->cmd_busy, timeout);
+        if (!rc) {
+                retval = -EIO;
+                err("Command not completed in %d msec\n", timeout_msec);
+        } else if (rc < 0) {
+                retval = -EINTR;
+                info("Command was interrupted by a signal\n");
+        }
+        ctrl->cmd_busy = 0;
+
+        return retval;
+}
+
 static int shpc_write_cmd(struct slot *slot, u8 t_slot, u8 cmd)
 {
         struct php_ctlr_state_s *php_ctlr = slot->ctrl->hpc_ctlr_handle;
@@ -314,8 +333,14 @@ static int shpc_write_cmd(struct slot *slot, u8 t_slot, u8 cmd)
         /* To make sure the Controller Busy bit is 0 before we send out the
          * command. 
          */
+        slot->ctrl->cmd_busy = 1;
         writew(temp_word, php_ctlr->creg + CMD);
 
+        /*
+         * Wait for command completion.
+         */
+        retval = shpc_wait_cmd(slot->ctrl);
+
         DBG_LEAVE_ROUTINE 
         return retval;
 }
@@ -1064,6 +1089,7 @@ static irqreturn_t shpc_isr(int IRQ, void *dev_id, struct pt_regs *regs)
                 temp_dword = readl(php_ctlr->creg + SERR_INTR_ENABLE);
                 temp_dword &= 0xfffdffff;
                 writel(temp_dword, php_ctlr->creg + SERR_INTR_ENABLE);
+                ctrl->cmd_busy = 0;
                 wake_up_interruptible(&ctrl->queue);
         }