The Intel cherrytrail xhci controller has an extended cap mmio-range
which contains registers to control the muxing to the xhci (host mode)
or the dwc3 (device mode) and vbus-detection for the otg usb-phy.

Having a mux driver included in the xhci code (or under drivers/usb/host)
is not desirable. So this commit adds a simple handler for this extended
capability, which creates a platform device with the caps mmio region as
resource, this allows us to write a separate platform mux driver for the
mux.

Signed-off-by: Hans de Goede <hdego...@redhat.com>
---
Changes in v2:
-Check xHCI controller PCI device-id instead of only checking for the
 Intel Extended capability ID, as the Extended capability ID is used on
 other model Intel xHCI controllers too
---
 drivers/usb/host/Makefile            |  2 +-
 drivers/usb/host/xhci-intel-quirks.c | 85 ++++++++++++++++++++++++++++++++++++
 drivers/usb/host/xhci-pci.c          |  4 ++
 drivers/usb/host/xhci.h              |  2 +
 4 files changed, 92 insertions(+), 1 deletion(-)
 create mode 100644 drivers/usb/host/xhci-intel-quirks.c

diff --git a/drivers/usb/host/Makefile b/drivers/usb/host/Makefile
index cf2691fffcc0..441edf82eb1c 100644
--- a/drivers/usb/host/Makefile
+++ b/drivers/usb/host/Makefile
@@ -63,7 +63,7 @@ obj-$(CONFIG_USB_OHCI_HCD_DAVINCI)    += ohci-da8xx.o
 obj-$(CONFIG_USB_UHCI_HCD)     += uhci-hcd.o
 obj-$(CONFIG_USB_FHCI_HCD)     += fhci.o
 obj-$(CONFIG_USB_XHCI_HCD)     += xhci-hcd.o
-obj-$(CONFIG_USB_XHCI_PCI)     += xhci-pci.o
+obj-$(CONFIG_USB_XHCI_PCI)     += xhci-pci.o xhci-intel-quirks.o
 obj-$(CONFIG_USB_XHCI_PLATFORM) += xhci-plat-hcd.o
 obj-$(CONFIG_USB_XHCI_MTK)     += xhci-mtk.o
 obj-$(CONFIG_USB_XHCI_TEGRA)   += xhci-tegra.o
diff --git a/drivers/usb/host/xhci-intel-quirks.c 
b/drivers/usb/host/xhci-intel-quirks.c
new file mode 100644
index 000000000000..819f5f9da9ee
--- /dev/null
+++ b/drivers/usb/host/xhci-intel-quirks.c
@@ -0,0 +1,85 @@
+/*
+ * Intel Vendor Defined XHCI extended capability handling
+ *
+ * Copyright (c) 2016) Hans de Goede <hdego...@redhat.com>
+ *
+ * Loosely based on android x86 kernel code which is:
+ *
+ * Copyright (C) 2014 Intel Corp.
+ *
+ * Author: Wu, Hao
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program;
+ */
+
+#include <linux/platform_device.h>
+#include "xhci.h"
+
+/* Extended capability IDs for Intel Vendor Defined */
+#define XHCI_EXT_CAPS_INTEL_HOST_CAP   192
+
+static void xhci_intel_unregister_pdev(void *arg)
+{
+       platform_device_unregister(arg);
+}
+
+int xhci_create_intel_cht_mux_pdev(struct xhci_hcd *xhci)
+{
+       struct usb_hcd *hcd = xhci_to_hcd(xhci);
+       struct device *dev = hcd->self.controller;
+       struct platform_device *pdev;
+       struct resource res = { 0, };
+       int ret, ext_offset;
+
+       ext_offset = xhci_find_next_ext_cap(&xhci->cap_regs->hc_capbase, 0,
+                                           XHCI_EXT_CAPS_INTEL_HOST_CAP);
+       if (!ext_offset) {
+               xhci_err(xhci, "couldn't find Intel ext caps\n");
+               return -ENODEV;
+       }
+
+       pdev = platform_device_alloc("intel_cht_usb_mux", PLATFORM_DEVID_NONE);
+       if (!pdev) {
+               xhci_err(xhci, "couldn't allocate intel_cht_usb_mux pdev\n");
+               return -ENOMEM;
+       }
+
+       res.start = hcd->rsrc_start + ext_offset;
+       res.end   = res.start + 0x3ff;
+       res.name  = "intel_cht_usb_mux";
+       res.flags = IORESOURCE_MEM;
+
+       ret = platform_device_add_resources(pdev, &res, 1);
+       if (ret) {
+               dev_err(dev, "couldn't add resources to intel_cht_usb_mux 
pdev\n");
+               platform_device_put(pdev);
+               return ret;
+       }
+
+       pdev->dev.parent = dev;
+
+       ret = platform_device_add(pdev);
+       if (ret) {
+               dev_err(dev, "couldn't register intel_cht_usb_mux pdev\n");
+               platform_device_put(pdev);
+               return ret;
+       }
+
+       ret = devm_add_action_or_reset(dev, xhci_intel_unregister_pdev, pdev);
+       if (ret) {
+               dev_err(dev, "couldn't add unregister action for 
intel_cht_usb_mux pdev\n");
+               return ret;
+       }
+
+       return 0;
+}
diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index 8071c8fdd15e..b55c1e96abf0 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -188,6 +188,7 @@ static void xhci_pci_quirks(struct device *dev, struct 
xhci_hcd *xhci)
        if (pdev->vendor == PCI_VENDOR_ID_INTEL &&
                 pdev->device == PCI_DEVICE_ID_INTEL_CHERRYVIEW_XHCI) {
                xhci->quirks |= XHCI_SSIC_PORT_UNUSED;
+               xhci->quirks |= XHCI_INTEL_CHT_USB_MUX;
        }
        if (pdev->vendor == PCI_VENDOR_ID_INTEL &&
            (pdev->device == PCI_DEVICE_ID_INTEL_CHERRYVIEW_XHCI ||
@@ -328,6 +329,9 @@ static int xhci_pci_probe(struct pci_dev *dev, const struct 
pci_device_id *id)
        if (xhci->quirks & XHCI_PME_STUCK_QUIRK)
                xhci_pme_acpi_rtd3_enable(dev);
 
+       if (xhci->quirks & XHCI_INTEL_CHT_USB_MUX)
+               xhci_create_intel_cht_mux_pdev(xhci);
+
        /* USB-2 and USB-3 roothubs initialized, allow runtime pm suspend */
        pm_runtime_put_noidle(&dev->dev);
 
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index e3e935291ed6..f722ee31e50d 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1821,6 +1821,7 @@ struct xhci_hcd {
 #define XHCI_LIMIT_ENDPOINT_INTERVAL_7 (1 << 26)
 #define XHCI_U2_DISABLE_WAKE   (1 << 27)
 #define XHCI_ASMEDIA_MODIFY_FLOWCONTROL        (1 << 28)
+#define XHCI_INTEL_CHT_USB_MUX (1 << 29)
 
        unsigned int            num_active_eps;
        unsigned int            limit_active_eps;
@@ -2005,6 +2006,7 @@ void xhci_init_driver(struct hc_driver *drv,
                      const struct xhci_driver_overrides *over);
 int xhci_disable_slot(struct xhci_hcd *xhci,
                        struct xhci_command *command, u32 slot_id);
+int xhci_create_intel_cht_mux_pdev(struct xhci_hcd *xhci);
 
 int xhci_suspend(struct xhci_hcd *xhci, bool do_wakeup);
 int xhci_resume(struct xhci_hcd *xhci, bool hibernated);
-- 
2.13.5

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