[PATCH] xhci: Add quirk to workaround the errata seen on Cavium Thunder-X2 Soc

[PATCH] xhci: Add quirk to workaround the errata seen on Cavium Thunder-X2 Soc

[Cherian, George]

From: "Cherian, George" <George.Cherian@cavium.com>

commit 11644a7659529730eaf2f166efaabe7c3dc7af8c upstream

Implement workaround for ThunderX2 Errata-129 (documented in
CN99XX Known Issues" available at Cavium support site).
As per ThunderX2errata-129, USB 2 device may come up as USB 1
if a connection to a USB 1 device is followed by another connection to
a USB 2 device, the link will come up as USB 1 for the USB 2 device.

Resolution: Reset the PHY after the USB 1 device is disconnected.
The PHY reset sequence is done using private registers in XHCI register
space. After the PHY is reset we check for the PLL lock status and retry
the operation if it fails. From our tests, retrying 4 times is sufficient.

Add a new quirk flag XHCI_RESET_PLL_ON_DISCONNECT to invoke the workaround
in handle_xhci_port_status().

Cc: stable@vger.kernel.org
Cc: stable@vger.kernel.org # 4.14.x: 36b6857: xhci: Allow more than 32 quirks
Signed-off-by: George Cherian <george.cherian@cavium.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
There is a conflict while cherry-pick of 36b6857: xhci: Allow more than
32 quirks. It is trivial to resolve. Let me know in case if it is an
issue.

 drivers/usb/host/xhci-pci.c  |  5 +++++
 drivers/usb/host/xhci-ring.c | 35 ++++++++++++++++++++++++++++++++++-
 drivers/usb/host/xhci.h      |  1 +
 3 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index 9218f506f8e3..4b07b6859b4c 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -236,6 +236,11 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci)
 	if (pdev->vendor == PCI_VENDOR_ID_TI && pdev->device == 0x8241)
 		xhci->quirks |= XHCI_LIMIT_ENDPOINT_INTERVAL_7;
 
+	if ((pdev->vendor == PCI_VENDOR_ID_BROADCOM ||
+	     pdev->vendor == PCI_VENDOR_ID_CAVIUM) &&
+	     pdev->device == 0x9026)
+		xhci->quirks |= XHCI_RESET_PLL_ON_DISCONNECT;
+
 	if (xhci->quirks & XHCI_RESET_ON_RESUME)
 		xhci_dbg_trace(xhci, trace_xhci_dbg_quirks,
 				"QUIRK: Resetting on resume");
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 6996235e34a9..ea35f346d26b 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -1568,6 +1568,35 @@ static void handle_device_notification(struct xhci_hcd *xhci,
 		usb_wakeup_notification(udev->parent, udev->portnum);
 }
 
+/*
+ * Quirk hanlder for errata seen on Cavium ThunderX2 processor XHCI
+ * Controller.
+ * As per ThunderX2errata-129 USB 2 device may come up as USB 1
+ * If a connection to a USB 1 device is followed by another connection
+ * to a USB 2 device.
+ *
+ * Reset the PHY after the USB device is disconnected if device speed
+ * is less than HCD_USB3.
+ * Retry the reset sequence max of 4 times checking the PLL lock status.
+ *
+ */
+static void xhci_cavium_reset_phy_quirk(struct xhci_hcd *xhci)
+{
+	struct usb_hcd *hcd = xhci_to_hcd(xhci);
+	u32 pll_lock_check;
+	u32 retry_count = 4;
+
+	do {
+		/* Assert PHY reset */
+		writel(0x6F, hcd->regs + 0x1048);
+		udelay(10);
+		/* De-assert the PHY reset */
+		writel(0x7F, hcd->regs + 0x1048);
+		udelay(200);
+		pll_lock_check = readl(hcd->regs + 0x1070);
+	} while (!(pll_lock_check & 0x1) && --retry_count);
+}
+
 static void handle_port_status(struct xhci_hcd *xhci,
 		union xhci_trb *event)
 {
@@ -1725,9 +1754,13 @@ static void handle_port_status(struct xhci_hcd *xhci,
 		goto cleanup;
 	}
 
-	if (hcd->speed < HCD_USB3)
+	if (hcd->speed < HCD_USB3) {
 		xhci_test_and_clear_bit(xhci, port_array, faked_port_index,
 					PORT_PLC);
+		if ((xhci->quirks & XHCI_RESET_PLL_ON_DISCONNECT) &&
+		    (portsc & PORT_CSC) && !(portsc & PORT_CONNECT))
+			xhci_cavium_reset_phy_quirk(xhci);
+	}
 
 cleanup:
 	/* Update event ring dequeue pointer before dropping the lock */
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index d7d2a3dfafb8..84457fc192fc 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1836,6 +1836,7 @@ struct xhci_hcd {
 #define XHCI_U2_DISABLE_WAKE	BIT_ULL(27)
 #define XHCI_ASMEDIA_MODIFY_FLOWCONTROL	BIT_ULL(28)
 #define XHCI_SUSPEND_DELAY	BIT_ULL(30)
+#define XHCI_RESET_PLL_ON_DISCONNECT	BIT_ULL(34)
 
 	unsigned int		num_active_eps;
 	unsigned int		limit_active_eps;
-- 
2.19.2

Re: [PATCH] xhci: Add quirk to workaround the errata seen on Cavium Thunder-X2 Soc

[Greg Kroah-Hartman]

On Thu, Nov 29, 2018 at 07:28:10AM +0000, Cherian, George wrote:
> From: "Cherian, George" <George.Cherian@cavium.com>
> 
> commit 11644a7659529730eaf2f166efaabe7c3dc7af8c upstream
> 
> Implement workaround for ThunderX2 Errata-129 (documented in
> CN99XX Known Issues" available at Cavium support site).
> As per ThunderX2errata-129, USB 2 device may come up as USB 1
> if a connection to a USB 1 device is followed by another connection to
> a USB 2 device, the link will come up as USB 1 for the USB 2 device.
> 
> Resolution: Reset the PHY after the USB 1 device is disconnected.
> The PHY reset sequence is done using private registers in XHCI register
> space. After the PHY is reset we check for the PLL lock status and retry
> the operation if it fails. From our tests, retrying 4 times is sufficient.
> 
> Add a new quirk flag XHCI_RESET_PLL_ON_DISCONNECT to invoke the workaround
> in handle_xhci_port_status().
> 
> Cc: stable@vger.kernel.org
> Cc: stable@vger.kernel.org # 4.14.x: 36b6857: xhci: Allow more than 32 quirks
> Signed-off-by: George Cherian <george.cherian@cavium.com>
> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
> There is a conflict while cherry-pick of 36b6857: xhci: Allow more than
> 32 quirks. It is trivial to resolve. Let me know in case if it is an
> issue.

I fixed it up, thanks.

greg k-h