commit d576bb9f2769b315a795f77f0c33322a976add7a
author Michael Hanselmann <linux-kernel@hansmi.ch> Thu May 31 23:34:27 2007 +0200
committer Greg Kroah-Hartman <gregkh@suse.de> Thu Jul 12 16:34:29 2007 -0700
tree 56d59afa4d1e96b519e81434bd09598f76bf1fee
parent 020363384adfb02f26c1c038a127ed3da3d5cf37

USB: Fix NEC OHCI chip silicon bug

This patch fixes a silicon bug in some NEC OHCI chips. The bug appears
at random times and is very, very difficult to reproduce. Without the
following patch, Linux would shut the chip and its associated devices
down. In Apple PowerBooks this leads to an unusable keyboard and mouse
(SSH still working). The idea of restarting the chip is taken from
public Darwin code.

Signed-off-by: Michael Hanselmann <linux-kernel@hansmi.ch>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/host/ohci-hcd.c

diff --git a/drivers/usb/host/ohci-hcd.c b/drivers/usb/host/ohci-hcd.c
index ce05e5f..44717fa 100644
--- a/drivers/usb/host/ohci-hcd.c
+++ b/drivers/usb/host/ohci-hcd.c
@@ -35,6 +35,7 @@
 #include <linux/dma-mapping.h>
 #include <linux/dmapool.h>
 #include <linux/reboot.h>
+#include <linux/workqueue.h>
 
 #include <asm/io.h>
 #include <asm/irq.h>
@@ -82,6 +83,8 @@
 static void ohci_dump (struct ohci_hcd *ohci, int verbose);
 static int ohci_init (struct ohci_hcd *ohci);
 static void ohci_stop (struct usb_hcd *hcd);
+static int ohci_restart (struct ohci_hcd *ohci);
+static void ohci_quirk_nec_worker (struct work_struct *work);
 
 #include "ohci-hub.c"
 #include "ohci-dbg.c"
@@ -651,9 +654,20 @@
 	}
 
 	if (ints & OHCI_INTR_UE) {
-		disable (ohci);
-		ohci_err (ohci, "OHCI Unrecoverable Error, disabled\n");
 		// e.g. due to PCI Master/Target Abort
+		if (ohci->flags & OHCI_QUIRK_NEC) {
+			/* Workaround for a silicon bug in some NEC chips used
+			 * in Apple's PowerBooks. Adapted from Darwin code.
+			 */
+			ohci_err (ohci, "OHCI Unrecoverable Error, scheduling NEC chip restart\n");
+
+			ohci_writel (ohci, OHCI_INTR_UE, &regs->intrdisable);
+
+			schedule_work (&ohci->nec_work);
+		} else {
+			disable (ohci);
+			ohci_err (ohci, "OHCI Unrecoverable Error, disabled\n");
+		}
 
 		ohci_dump (ohci, 1);
 		ohci_usb_reset (ohci);
@@ -755,23 +769,16 @@
 /*-------------------------------------------------------------------------*/
 
 /* must not be called from interrupt context */
-
-#ifdef	CONFIG_PM
-
 static int ohci_restart (struct ohci_hcd *ohci)
 {
 	int temp;
 	int i;
 	struct urb_priv *priv;
 
-	/* mark any devices gone, so they do nothing till khubd disconnects.
-	 * recycle any "live" eds/tds (and urbs) right away.
-	 * later, khubd disconnect processing will recycle the other state,
-	 * (either as disconnect/reconnect, or maybe someday as a reset).
-	 */
 	spin_lock_irq(&ohci->lock);
 	disable (ohci);
-	usb_root_hub_lost_power(ohci_to_hcd(ohci)->self.root_hub);
+
+	/* Recycle any "live" eds/tds (and urbs). */
 	if (!list_empty (&ohci->pending))
 		ohci_dbg(ohci, "abort schedule...\n");
 	list_for_each_entry (priv, &ohci->pending, pending) {
@@ -822,7 +829,27 @@
 	ohci_dbg(ohci, "restart complete\n");
 	return 0;
 }
-#endif
+
+/*-------------------------------------------------------------------------*/
+
+/* NEC workaround */
+static void ohci_quirk_nec_worker(struct work_struct *work)
+{
+	struct ohci_hcd *ohci = container_of(work, struct ohci_hcd, nec_work);
+	int status;
+
+	status = ohci_init(ohci);
+	if (status != 0) {
+		ohci_err(ohci, "Restarting NEC controller failed "
+			 "in ohci_init, %d\n", status);
+		return;
+	}
+
+	status = ohci_restart(ohci);
+	if (status != 0)
+		ohci_err(ohci, "Restarting NEC controller failed "
+			 "in ohci_restart, %d\n", status);
+}
 
 /*-------------------------------------------------------------------------*/