From: Kei Tokunaga<ktokunag@redhat.com>
Subject: [RHEL5 PATCH] SHPCHP driver doesn't work in poll mode
Date: Tue, 14 Nov 2006 16:19:17
Bugzilla: 211679
Message-Id: <455A32D5.5090404@redhat.com>
Changelog: SHPCHP driver doesn't work in poll mode

BZ211679
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=211679

This patch is in upstream.
http://www.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=b4a1efffcf8070dbc7734f27da10ce49fb9f2a34

SHPC command always fails with the following message if
the SHPCHP driver is loaded with poll event mode enabled.

   shpchp: Command not completed in 2000 msec
   shpchp: hpc_slot_disable: Write command failed!
   shpchp: remove_board: Issue of Slot Disable command failed

wait_event_interruptible_timeout() was called in shpc_wait_cmd()
even in polling mode, which caused this issue.  This patch adds
a new function 'shpc_poll_ctrl_busy()', which was the same code
performed in shpc_write_cmd(), for polling mode and makes
shpc_wait_cmd() and shpc_write_cmd() call the function.

The patch applies to 2.6.18-1.2747.el5.

BZ215561 depends on this bug.

Thanks,
Kei
--
Fujitsu On-site Engineer
---

 linux-2.6.18-1.2747.el5-kei/./drivers/pci/hotplug/shpchp_hpc.c |   54 ++++++----
 1 file changed, 35 insertions(+), 19 deletions(-)

diff -puN ./drivers/pci/hotplug/shpchp_hpc.c~bz211679-fix_SHPCHP-poll_mode ./drivers/pci/hotplug/shpchp_hpc.c
--- linux-2.6.18-1.2747.el5/./drivers/pci/hotplug/shpchp_hpc.c~bz211679-fix_SHPCHP-poll_mode	2006-11-14 14:32:39.000000000 -0500
+++ linux-2.6.18-1.2747.el5-kei/./drivers/pci/hotplug/shpchp_hpc.c	2006-11-14 14:36:59.000000000 -0500
@@ -302,16 +302,43 @@ static void start_int_poll_timer(struct 
 	add_timer(&php_ctlr->int_poll_timer);
 }
 
+/*
+ * Returns 1 if SHPC finishes executing a command within 1 sec,
+ * otherwise returns 0.
+ */
+static inline int shpc_poll_ctrl_busy(struct controller *ctrl)
+{
+	int i;
+	u16 cmd_status = shpc_readw(ctrl, CMD_STATUS);
+
+	if (!(cmd_status & 0x1))
+		return 1;
+
+	/* Check every 0.1 sec for a total of 1 sec */
+	for (i = 0; i < 10; i++) {
+		msleep(100);
+		cmd_status = shpc_readw(ctrl, CMD_STATUS);
+		if (!(cmd_status & 0x1))
+			return 1;
+	}
+
+	return 0;
+}
+
 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);
+	unsigned long timeout = msecs_to_jiffies(1000);
+	int rc;
+
+	if (shpchp_poll_mode)
+		rc = shpc_poll_ctrl_busy(ctrl);
+	else
+		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);
+		err("Command not completed in 1000 msec\n");
 	} else if (rc < 0) {
 		retval = -EINTR;
 		info("Command was interrupted by a signal\n");
@@ -327,26 +354,15 @@ static int shpc_write_cmd(struct slot *s
 	u16 cmd_status;
 	int retval = 0;
 	u16 temp_word;
-	int i;
 
 	DBG_ENTER_ROUTINE 
 
 	mutex_lock(&slot->ctrl->cmd_lock);
 
-	for (i = 0; i < 10; i++) {
-		cmd_status = shpc_readw(ctrl, CMD_STATUS);
-		
-		if (!(cmd_status & 0x1))
-			break;
-		/*  Check every 0.1 sec for a total of 1 sec*/
-		msleep(100);
-	}
-
-	cmd_status = shpc_readw(ctrl, CMD_STATUS);
-	
-	if (cmd_status & 0x1) { 
+	if (!shpc_poll_ctrl_busy(ctrl)) {
 		/* After 1 sec and and the controller is still busy */
-		err("%s : Controller is still busy after 1 sec.\n", __FUNCTION__);
+		err("%s : Controller is still busy after 1 sec.\n",
+		    __FUNCTION__);
 		retval = -EBUSY;
 		goto out;
 	}

_