Re: [linux-usb-devel] [PATCH] Fix NEC OHCI chip silicon bug

[Michael Hanselmann <linux-kernel@hansmi.ch>]

On Fri, Jun 01, 2007 at 10:19:30AM -0400, Alan Stern wrote:
> > @@ -779,7 +790,11 @@ static int ohci_restart (struct ohci_hcd
> >  	 */
> >  	spin_lock_irq(&ohci->lock);
> >  	disable (ohci);
> > +
> > +#ifdef CONFIG_PM
> >  	usb_root_hub_lost_power(ohci_to_hcd(ohci)->self.root_hub);
> > +#endif
> > +

> Suppose CONFIG_PM isn't defined.  How are you going to let usbcore 
> know about all the old connections which no longer exist?

You're right, something is wrong there. The patch below uses
usb_root_hub_lost_power again but disables CONFIG_PM specific code in it
when CONFIG_PM isn't defined. It seems to work for me with and without
CONFIG_PM, but I have to confess I might not know enough about Linux'
USB core. Is it better now?

Signed-off-by: Michael Hanselmann <linux-kernel@hansmi.ch>

---
diff -Nurp --exclude-from=linux-exclude-from linux-2.6.22-rc3.orig/drivers/usb/core/hub.c linux-2.6.22-rc3/drivers/usb/core/hub.c
--- linux-2.6.22-rc3.orig/drivers/usb/core/hub.c	2007-05-31 22:53:54.000000000 +0200
+++ linux-2.6.22-rc3/drivers/usb/core/hub.c	2007-06-02 14:34:13.000000000 +0200
@@ -1089,9 +1089,6 @@ void usb_set_device_state(struct usb_dev
 	spin_unlock_irqrestore(&device_state_lock, flags);
 }
 
-
-#ifdef	CONFIG_PM
-
 /**
  * usb_root_hub_lost_power - called by HCD if the root hub lost Vbus power
  * @rhdev: struct usb_device for the root hub
@@ -1109,10 +1106,12 @@ void usb_root_hub_lost_power(struct usb_
 
 	dev_warn(&rhdev->dev, "root hub lost power or was reset\n");
 
+#ifdef CONFIG_PM
 	/* Make sure no potential wakeup events get lost,
 	 * by forcing the root hub to be resumed.
 	 */
 	rhdev->dev.power.prev_state.event = PM_EVENT_ON;
+#endif /* CONFIG_PM */
 
 	spin_lock_irqsave(&device_state_lock, flags);
 	hub = hdev_to_hub(rhdev);
@@ -1127,8 +1126,6 @@ void usb_root_hub_lost_power(struct usb_
 }
 EXPORT_SYMBOL_GPL(usb_root_hub_lost_power);
 
-#endif	/* CONFIG_PM */
-
 static void choose_address(struct usb_device *udev)
 {
 	int		devnum;
diff -Nurp --exclude-from=linux-exclude-from linux-2.6.22-rc3.orig/drivers/usb/host/ohci.h linux-2.6.22-rc3/drivers/usb/host/ohci.h
--- linux-2.6.22-rc3.orig/drivers/usb/host/ohci.h	2007-05-31 22:53:54.000000000 +0200
+++ linux-2.6.22-rc3/drivers/usb/host/ohci.h	2007-05-31 22:54:27.000000000 +0200
@@ -397,8 +397,10 @@ struct ohci_hcd {
 #define	OHCI_QUIRK_BE_DESC	0x08			/* BE descriptors */
 #define	OHCI_QUIRK_BE_MMIO	0x10			/* BE registers */
 #define	OHCI_QUIRK_ZFMICRO	0x20			/* Compaq ZFMicro chipset*/
+#define	OHCI_QUIRK_NEC		0x40			/* lost interrupts */
 	// there are also chip quirks/bugs in init logic
 
+	struct work_struct	nec_work;	/* Worker for NEC quirk */
 };
 
 /* convert between an hcd pointer and the corresponding ohci_hcd */
diff -Nurp --exclude-from=linux-exclude-from linux-2.6.22-rc3.orig/drivers/usb/host/ohci-hcd.c linux-2.6.22-rc3/drivers/usb/host/ohci-hcd.c
--- linux-2.6.22-rc3.orig/drivers/usb/host/ohci-hcd.c	2007-05-31 22:53:54.000000000 +0200
+++ linux-2.6.22-rc3/drivers/usb/host/ohci-hcd.c	2007-06-02 14:35:18.000000000 +0200
@@ -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 const char	hcd_name [] = "ohci_hc
 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"
@@ -659,9 +662,20 @@ static irqreturn_t ohci_irq (struct usb_
 	}
 
 	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);
@@ -763,9 +777,6 @@ static void ohci_stop (struct usb_hcd *h
 /*-------------------------------------------------------------------------*/
 
 /* must not be called from interrupt context */
-
-#ifdef	CONFIG_PM
-
 static int ohci_restart (struct ohci_hcd *ohci)
 {
 	int temp;
@@ -839,7 +850,27 @@ static int ohci_restart (struct ohci_hcd
 	}
 	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);
+}
 
 /*-------------------------------------------------------------------------*/
 
diff -Nurp --exclude-from=linux-exclude-from linux-2.6.22-rc3.orig/drivers/usb/host/ohci-hub.c linux-2.6.22-rc3/drivers/usb/host/ohci-hub.c
--- linux-2.6.22-rc3.orig/drivers/usb/host/ohci-hub.c	2007-05-31 22:53:54.000000000 +0200
+++ linux-2.6.22-rc3/drivers/usb/host/ohci-hub.c	2007-05-31 22:54:27.000000000 +0200
@@ -55,8 +55,6 @@ static void dl_done_list (struct ohci_hc
 static void finish_unlinks (struct ohci_hcd *, u16);
 
 #ifdef	CONFIG_PM
-static int ohci_restart(struct ohci_hcd *ohci);
-
 static int ohci_rh_suspend (struct ohci_hcd *ohci, int autostop)
 __releases(ohci->lock)
 __acquires(ohci->lock)
diff -Nurp --exclude-from=linux-exclude-from linux-2.6.22-rc3.orig/drivers/usb/host/ohci-mem.c linux-2.6.22-rc3/drivers/usb/host/ohci-mem.c
--- linux-2.6.22-rc3.orig/drivers/usb/host/ohci-mem.c	2007-05-31 22:53:54.000000000 +0200
+++ linux-2.6.22-rc3/drivers/usb/host/ohci-mem.c	2007-05-31 23:24:43.000000000 +0200
@@ -28,6 +28,7 @@ static void ohci_hcd_init (struct ohci_h
 	ohci->next_statechange = jiffies;
 	spin_lock_init (&ohci->lock);
 	INIT_LIST_HEAD (&ohci->pending);
+	INIT_WORK (&ohci->nec_work, ohci_quirk_nec_worker);
 }
 
 /*-------------------------------------------------------------------------*/
diff -Nurp --exclude-from=linux-exclude-from linux-2.6.22-rc3.orig/drivers/usb/host/ohci-pci.c linux-2.6.22-rc3/drivers/usb/host/ohci-pci.c
--- linux-2.6.22-rc3.orig/drivers/usb/host/ohci-pci.c	2007-05-31 22:53:54.000000000 +0200
+++ linux-2.6.22-rc3/drivers/usb/host/ohci-pci.c	2007-05-31 22:54:27.000000000 +0200
@@ -111,6 +111,18 @@ static int ohci_quirk_toshiba_scc(struct
 #endif
 }
 
+/* Check for NEC chip and apply quirk for allegedly lost interrupts.
+ */
+static int ohci_quirk_nec(struct usb_hcd *hcd)
+{
+	struct ohci_hcd	*ohci = hcd_to_ohci (hcd);
+
+	ohci->flags |= OHCI_QUIRK_NEC;
+	ohci_dbg (ohci, "enabled NEC chipset lost interrupt quirk\n");
+
+	return 0;
+}
+
 /* List of quirks for OHCI */
 static const struct pci_device_id ohci_pci_quirks[] = {
 	{
@@ -134,6 +146,10 @@ static const struct pci_device_id ohci_p
 		.driver_data = (unsigned long)ohci_quirk_toshiba_scc,
 	},
 	{
+		PCI_DEVICE(PCI_VENDOR_ID_NEC, PCI_DEVICE_ID_NEC_USB),
+		.driver_data = (unsigned long)ohci_quirk_nec,
+	},
+	{
 		/* Toshiba portege 4000 */
 		.vendor		= PCI_VENDOR_ID_AL,
 		.device		= 0x5237,