Patch "usb: host: xhci: add a new quirk XHCI_NO_64BIT_SUPPORT" has been added to the 4.5-stable tree

This is a note to let you know that I've just added the patch titled

usb: host: xhci: add a new quirk XHCI_NO_64BIT_SUPPORT

to the 4.5-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
usb-host-xhci-add-a-new-quirk-xhci_no_64bit_support.patch
and it can be found in the queue-4.5 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Yoshihiro Shimoda <[email protected]>
Date: Fri, 8 Apr 2016 16:25:07 +0300
Subject: usb: host: xhci: add a new quirk XHCI_NO_64BIT_SUPPORT

From: Yoshihiro Shimoda <[email protected]>

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.

---
 drivers/usb/host/xhci.c |   10 ++++++++++
 drivers/usb/host/xhci.h |    1 +
 2 files changed, 11 insertions(+)

@@ -4944,6 +4944,16 @@ int xhci_gen_setup(struct usb_hcd *hcd,
 		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) &&

@@ -1632,6 +1632,7 @@ struct xhci_hcd {
 #define XHCI_PME_STUCK_QUIRK	(1 << 20)
 #define XHCI_MTK_HOST		(1 << 21)
 #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 */

Patches currently in stable-queue which might be from [email protected] are

queue-4.5/usb-host-xhci-plat-make-enum-xhci_plat_type-start-at-a-non-zero-value.patch queue-4.5/usb-host-xhci-plat-fix-cannot-work-if-r-car-gen2-3-run-on-above-4gb-phys.patch queue-4.5/usb-host-xhci-add-a-new-quirk-xhci_no_64bit_support.patch