[4.2.y-ckt stable] Patch "usb: host: xhci: add a new quirk XHCI_NO_64BIT_SUPPORT" has been added to the 4.2.y-ckt tree

[Kamal Mostafa]

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

    usb: host: xhci: add a new quirk XHCI_NO_64BIT_SUPPORT

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-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 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From 463cb5b6f00167a7bf464356328e8b3149079e3f Mon Sep 17 00:00:00 2001
From: Yoshihiro Shimoda <yoshihiro.shimoda.uh at renesas.com>
Date: Fri, 8 Apr 2016 16:25:07 +0300
Subject: usb: host: xhci: add a new quirk XHCI_NO_64BIT_SUPPORT

commit 0a380be8233dbf8dd20795b801c5d5d5ef3992f7 upstream.

On some xHCI controllers (e.g. R-Car SoCs), the AC64 bit (bit 0) of
HCCPARAMS1 is set to 1. However, the xHCs don't support 64-bit
address memory pointers actually. So, in this case, this driver should
call dma_set_coherent_mask(dev, DMA_BIT_MASK(32)) in xhci_gen_setup().
Otherwise, the xHCI controller will be died after a usb device is
connected if it runs on above 4GB physical memory environment.

So, this patch adds a new quirk XHCI_NO_64BIT_SUPPORT to resolve
such an issue.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh at renesas.com>
Reviewed-by: Felipe Balbi <felipe.balbi at linux.intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman at linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/usb/host/xhci.c | 10 ++++++++++
 drivers/usb/host/xhci.h |  1 +
 2 files changed, 11 insertions(+)

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index f2f3c0b..21f638d 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -4924,6 +4924,16 @@ int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks)
 		return retval;
 	xhci_dbg(xhci, "Reset complete\n");

+	/*
+	 * On some xHCI controllers (e.g. R-Car SoCs), the AC64 bit (bit 0)
+	 * of HCCPARAMS1 is set to 1. However, the xHCs don't support 64-bit
+	 * address memory pointers actually. So, this driver clears the AC64
+	 * bit of xhci->hcc_params to call dma_set_coherent_mask(dev,
+	 * DMA_BIT_MASK(32)) in this xhci_gen_setup().
+	 */
+	if (xhci->quirks & XHCI_NO_64BIT_SUPPORT)
+		xhci->hcc_params &= ~BIT(0);
+
 	/* Set dma_mask and coherent_dma_mask to 64-bits,
 	 * if xHC supports 64-bit addressing */
 	if (HCC_64BIT_ADDR(xhci->hcc_params) &&
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index d77ce5f..82be4b5 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1569,6 +1569,7 @@ struct xhci_hcd {
 #define XHCI_BROKEN_STREAMS	(1 << 19)
 #define XHCI_PME_STUCK_QUIRK	(1 << 20)
 #define XHCI_SSIC_PORT_UNUSED	(1 << 22)
+#define XHCI_NO_64BIT_SUPPORT	(1 << 23)
 	unsigned int		num_active_eps;
 	unsigned int		limit_active_eps;
 	/* There are two roothubs to keep track of bus suspend info for */
--
2.7.4