OHCI: final fix for NVIDIA problems (I hope)

Problems with NVIDIA's OHCI host controllers persist.  After looking
carefully through the spec, I finally realized that when a controller
is reset it then automatically goes into a SUSPEND state in which it
is completely quiescent (no DMA and no IRQs) and from which it will
not awaken until the system puts it into the OPERATIONAL state.

Therefore there's no need to worry about controllers being in the
RESET state for extended periods, or remaining in the OPERATIONAL
state during system shutdown.  The proper action for device
initialization is to put the controller into the RESET state (if it's
not there already) and then to issue a software reset.  Similarly, the
proper action for device shutdown is simply to do a software reset.

This patch (as1499) implements such an approach.  It simplifies
initialization and shutdown, and allows the NVIDIA shutdown-quirk code
to be removed.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Andre "Osku" Schmidt <andre.osku.schmidt@googlemail.com>
Tested-by: Arno Augustin <Arno.Augustin@web.de>
Cc: stable <stable@vger.kernel.org> [after tested in 3.2 for a while]
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/host/ohci-hcd.c

@@ -389,17 +389,14 @@ ohci_shutdown (struct usb_hcd *hcd)
 	struct ohci_hcd *ohci;
 
 	ohci = hcd_to_ohci (hcd);
-	ohci_writel (ohci, OHCI_INTR_MIE, &ohci->regs->intrdisable);
-	ohci->hc_control = ohci_readl(ohci, &ohci->regs->control);
+	ohci_writel(ohci, (u32) ~0, &ohci->regs->intrdisable);
 
-	/* If the SHUTDOWN quirk is set, don't put the controller in RESET */
-	ohci->hc_control &= (ohci->flags & OHCI_QUIRK_SHUTDOWN ?
-			OHCI_CTRL_RWC | OHCI_CTRL_HCFS :
-			OHCI_CTRL_RWC);
-	ohci_writel(ohci, ohci->hc_control, &ohci->regs->control);
+	/* Software reset, after which the controller goes into SUSPEND */
+	ohci_writel(ohci, OHCI_HCR, &ohci->regs->cmdstatus);
+	ohci_readl(ohci, &ohci->regs->cmdstatus);	/* flush the writes */
+	udelay(10);
 
-	/* flush the writes */
-	(void) ohci_readl (ohci, &ohci->regs->control);
+	ohci_writel(ohci, ohci->fminterval, &ohci->regs->fminterval);
 }
 
 static int check_ed(struct ohci_hcd *ohci, struct ed *ed)

drivers/usb/host/ohci-pci.c

@@ -175,28 +175,6 @@ static int ohci_quirk_amd700(struct usb_hcd *hcd)
 	return 0;
 }
 
-/* nVidia controllers continue to drive Reset signalling on the bus
- * even after system shutdown, wasting power.  This flag tells the
- * shutdown routine to leave the controller OPERATIONAL instead of RESET.
- */
-static int ohci_quirk_nvidia_shutdown(struct usb_hcd *hcd)
-{
-	struct pci_dev *pdev = to_pci_dev(hcd->self.controller);
-	struct ohci_hcd	*ohci = hcd_to_ohci(hcd);
-
-	/* Evidently nVidia fixed their later hardware; this is a guess at
-	 * the changeover point.
-	 */
-#define PCI_DEVICE_ID_NVIDIA_NFORCE_MCP51_USB		0x026d
-
-	if (pdev->device < PCI_DEVICE_ID_NVIDIA_NFORCE_MCP51_USB) {
-		ohci->flags |= OHCI_QUIRK_SHUTDOWN;
-		ohci_dbg(ohci, "enabled nVidia shutdown quirk\n");
-	}
-
-	return 0;
-}
-
 static void sb800_prefetch(struct ohci_hcd *ohci, int on)
 {
 	struct pci_dev *pdev;
@@ -260,10 +238,6 @@ static const struct pci_device_id ohci_pci_quirks[] = {
 		PCI_DEVICE(PCI_VENDOR_ID_ATI, 0x4399),
 		.driver_data = (unsigned long)ohci_quirk_amd700,
 	},
-	{
-		PCI_DEVICE(PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID),
-		.driver_data = (unsigned long) ohci_quirk_nvidia_shutdown,
-	},
 
 	/* FIXME for some of the early AMD 760 southbridges, OHCI
 	 * won't work at all.  blacklist them.

drivers/usb/host/ohci.h

@@ -403,7 +403,6 @@ struct ohci_hcd {
 #define	OHCI_QUIRK_HUB_POWER	0x100			/* distrust firmware power/oc setup */
 #define	OHCI_QUIRK_AMD_PLL	0x200			/* AMD PLL quirk*/
 #define	OHCI_QUIRK_AMD_PREFETCH	0x400			/* pre-fetch for ISO transfer */
-#define	OHCI_QUIRK_SHUTDOWN	0x800			/* nVidia power bug */
 	// there are also chip quirks/bugs in init logic
 
 	struct work_struct	nec_work;	/* Worker for NEC quirk */

drivers/usb/host/pci-quirks.c

@@ -37,6 +37,7 @@
 #define OHCI_INTRENABLE		0x10
 #define OHCI_INTRDISABLE	0x14
 #define OHCI_FMINTERVAL		0x34
+#define OHCI_HCFS		(3 << 6)	/* hc functional state */
 #define OHCI_HCR		(1 << 0)	/* host controller reset */
 #define OHCI_OCR		(1 << 3)	/* ownership change request */
 #define OHCI_CTRL_RWC		(1 << 9)	/* remote wakeup connected */
@@ -466,6 +467,8 @@ static void __devinit quirk_usb_handoff_ohci(struct pci_dev *pdev)
 {
 	void __iomem *base;
 	u32 control;
+	u32 fminterval;
+	int cnt;
 
 	if (!mmio_resource_enabled(pdev, 0))
 		return;
@@ -498,41 +501,32 @@ static void __devinit quirk_usb_handoff_ohci(struct pci_dev *pdev)
 	}
 #endif
 
-	/* reset controller, preserving RWC (and possibly IR) */
-	writel(control & OHCI_CTRL_MASK, base + OHCI_CONTROL);
-	readl(base + OHCI_CONTROL);
+	/* disable interrupts */
+	writel((u32) ~0, base + OHCI_INTRDISABLE);
 
-	/* Some NVIDIA controllers stop working if kept in RESET for too long */
-	if (pdev->vendor == PCI_VENDOR_ID_NVIDIA) {
-		u32 fminterval;
-		int cnt;
+	/* Reset the USB bus, if the controller isn't already in RESET */
+	if (control & OHCI_HCFS) {
+		/* Go into RESET, preserving RWC (and possibly IR) */
+		writel(control & OHCI_CTRL_MASK, base + OHCI_CONTROL);
+		readl(base + OHCI_CONTROL);
 
-		/* drive reset for at least 50 ms (7.1.7.5) */
+		/* drive bus reset for at least 50 ms (7.1.7.5) */
 		msleep(50);
+	}
 
-		/* software reset of the controller, preserving HcFmInterval */
-		fminterval = readl(base + OHCI_FMINTERVAL);
-		writel(OHCI_HCR, base + OHCI_CMDSTATUS);
+	/* software reset of the controller, preserving HcFmInterval */
+	fminterval = readl(base + OHCI_FMINTERVAL);
+	writel(OHCI_HCR, base + OHCI_CMDSTATUS);
 
-		/* reset requires max 10 us delay */
-		for (cnt = 30; cnt > 0; --cnt) {	/* ... allow extra time */
-			if ((readl(base + OHCI_CMDSTATUS) & OHCI_HCR) == 0)
-				break;
-			udelay(1);
-		}
-		writel(fminterval, base + OHCI_FMINTERVAL);
-
-		/* Now we're in the SUSPEND state with all devices reset
-		 * and wakeups and interrupts disabled
-		 */
+	/* reset requires max 10 us delay */
+	for (cnt = 30; cnt > 0; --cnt) {	/* ... allow extra time */
+		if ((readl(base + OHCI_CMDSTATUS) & OHCI_HCR) == 0)
+			break;
+		udelay(1);
 	}
+	writel(fminterval, base + OHCI_FMINTERVAL);
 
-	/*
-	 * disable interrupts
-	 */
-	writel(~(u32)0, base + OHCI_INTRDISABLE);
-	writel(~(u32)0, base + OHCI_INTRSTATUS);
-
+	/* Now the controller is safely in SUSPEND and nothing can wake it up */
 	iounmap(base);
 }