[3.16.y-ckt stable] Patch "xhci: Workaround for PME stuck issues in Intel xhci" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    xhci: Workaround for PME stuck issues in Intel xhci

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt9.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 41f2c3775f077fbfdc301b185c2ff24cd683c337 Mon Sep 17 00:00:00 2001
From: Mathias Nyman <mathias.nyman at linux.intel.com>
Date: Fri, 6 Mar 2015 17:23:19 +0200
Subject: xhci: Workaround for PME stuck issues in Intel xhci

commit b8cb91e058cd0c0f02059c1207293c5b31d350fa upstream.

The xhci in Intel Sunrisepoint and Cherryview platforms need a driver
workaround for a Stuck PME that might either block PME events in suspend,
or create spurious PME events preventing runtime suspend.

Workaround is to clear a internal PME flag, BIT(28) in a vendor specific
PMCTRL register at offset 0x80a4, in both suspend resume callbacks

Without this, xhci connected usb devices might never be able to wake up the
system from suspend, or prevent device from going to suspend (xhci d3)

Signed-off-by: Mathias Nyman <mathias.nyman at linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/usb/host/xhci-pci.c | 30 ++++++++++++++++++++++++++++++
 drivers/usb/host/xhci.h     |  1 +
 2 files changed, 31 insertions(+)

diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index fd8c8e669cac..c947bfd260a9 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -37,6 +37,9 @@

 #define PCI_DEVICE_ID_INTEL_LYNXPOINT_XHCI	0x8c31
 #define PCI_DEVICE_ID_INTEL_LYNXPOINT_LP_XHCI	0x9c31
+#define PCI_DEVICE_ID_INTEL_CHERRYVIEW_XHCI		0x22b5
+#define PCI_DEVICE_ID_INTEL_SUNRISEPOINT_H_XHCI		0xa12f
+#define PCI_DEVICE_ID_INTEL_SUNRISEPOINT_LP_XHCI	0x9d2f

 static const char hcd_name[] = "xhci_hcd";

@@ -131,6 +134,12 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci)
 		pdev->device == PCI_DEVICE_ID_INTEL_LYNXPOINT_LP_XHCI) {
 		xhci->quirks |= XHCI_SPURIOUS_REBOOT;
 	}
+	if (pdev->vendor == PCI_VENDOR_ID_INTEL &&
+		(pdev->device == PCI_DEVICE_ID_INTEL_SUNRISEPOINT_LP_XHCI ||
+		 pdev->device == PCI_DEVICE_ID_INTEL_SUNRISEPOINT_H_XHCI ||
+		 pdev->device == PCI_DEVICE_ID_INTEL_CHERRYVIEW_XHCI)) {
+		xhci->quirks |= XHCI_PME_STUCK_QUIRK;
+	}
 	if (pdev->vendor == PCI_VENDOR_ID_ETRON &&
 			pdev->device == PCI_DEVICE_ID_ASROCK_P67) {
 		xhci->quirks |= XHCI_RESET_ON_RESUME;
@@ -157,6 +166,21 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci)
 				"QUIRK: Resetting on resume");
 }

+/*
+ * Make sure PME works on some Intel xHCI controllers by writing 1 to clear
+ * the Internal PME flag bit in vendor specific PMCTRL register at offset 0x80a4
+ */
+static void xhci_pme_quirk(struct xhci_hcd *xhci)
+{
+	u32 val;
+	void __iomem *reg;
+
+	reg = (void __iomem *) xhci->cap_regs + 0x80a4;
+	val = readl(reg);
+	writel(val | BIT(28), reg);
+	readl(reg);
+}
+
 /* called during probe() after chip reset completes */
 static int xhci_pci_setup(struct usb_hcd *hcd)
 {
@@ -281,6 +305,9 @@ static int xhci_pci_suspend(struct usb_hcd *hcd, bool do_wakeup)
 	if (xhci_compliance_mode_recovery_timer_quirk_check())
 		pdev->no_d3cold = true;

+	if (xhci->quirks & XHCI_PME_STUCK_QUIRK)
+		xhci_pme_quirk(xhci);
+
 	return xhci_suspend(xhci, do_wakeup);
 }

@@ -311,6 +338,9 @@ static int xhci_pci_resume(struct usb_hcd *hcd, bool hibernated)
 	if (pdev->vendor == PCI_VENDOR_ID_INTEL)
 		usb_enable_intel_xhci_ports(pdev);

+	if (xhci->quirks & XHCI_PME_STUCK_QUIRK)
+		xhci_pme_quirk(xhci);
+
 	retval = xhci_resume(xhci, hibernated);
 	return retval;
 }
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 5b6a8ddda5cb..d40a72b69f26 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1564,6 +1564,7 @@ struct xhci_hcd {
 #define XHCI_SPURIOUS_WAKEUP	(1 << 18)
 /* For controllers with a broken beyond repair streams implementation */
 #define XHCI_BROKEN_STREAMS	(1 << 19)
+#define XHCI_PME_STUCK_QUIRK	(1 << 20)
 	unsigned int		num_active_eps;
 	unsigned int		limit_active_eps;
 	/* There are two roothubs to keep track of bus suspend info for */