patch "usb: host: xhci: add a new quirk XHCI_NO_64BIT_SUPPORT" added to usb-linus

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 my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

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

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(+)

index b60928802686..9283d3331b59 100644
@@ -4948,6 +4948,16 @@ 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) &&

index e293e0974f48..70f215c20b2b 100644
@@ -1641,6 +1641,7 @@ 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 */

2.8.0