xhci: Add Intel extended cap / otg phy mux handling

The xHCI controller on various Intel SoCs 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 role-sw driver included in the xHCI code (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 role-sw driver for
the role-switch.

Note this commit adds a call to the new xhci_ext_cap_init() function
to xhci_pci_probe(), it is added here because xhci_ext_cap_init() must
be called only once. If in the future we also want to handle ext-caps
on non pci xHCI HCDs from xhci_ext_cap_init() a call to it should also
be added to other bus probe paths.

Signed-off-by: Hans de Goede <[e-mail]>
Acked-by: Mathias Nyman <[e-mail]>
Reviewed-by: Andy Shevchenko <[e-mail]>
Signed-off-by: Heikki Krogerus <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/host/Makefile

···
 
 fhci-$(CONFIG_FHCI_DEBUG) += fhci-dbg.o
 
-xhci-hcd-y := xhci.o xhci-mem.o
+xhci-hcd-y := xhci.o xhci-mem.o xhci-ext-caps.o
 xhci-hcd-y += xhci-ring.o xhci-hub.o xhci-dbg.o
 xhci-hcd-y += xhci-trace.o
 

drivers/usb/host/xhci-ext-caps.c

···
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * XHCI extended capability handling
+ *
+ * Copyright (c) 2017 Hans de Goede <[e-mail]>
+ */
+
+#include <linux/platform_device.h>
+#include "xhci.h"
+
+#define USB_SW_DRV_NAME		"intel_xhci_usb_sw"
+#define USB_SW_RESOURCE_SIZE	0x400
+
+static void xhci_intel_unregister_pdev(void *arg)
+{
+	platform_device_unregister(arg);
+}
+
+static int xhci_create_intel_xhci_sw_pdev(struct xhci_hcd *xhci, u32 cap_offset)
+{
+	struct usb_hcd *hcd = xhci_to_hcd(xhci);
+	struct device *dev = hcd->self.controller;
+	struct platform_device *pdev;
+	struct resource	res = { 0, };
+	int ret;
+
+	pdev = platform_device_alloc(USB_SW_DRV_NAME, PLATFORM_DEVID_NONE);
+	if (!pdev) {
+		xhci_err(xhci, "couldn't allocate %s platform device\n",
+			 USB_SW_DRV_NAME);
+		return -ENOMEM;
+	}
+
+	res.start = hcd->rsrc_start + cap_offset;
+	res.end	  = res.start + USB_SW_RESOURCE_SIZE - 1;
+	res.name  = USB_SW_DRV_NAME;
+	res.flags = IORESOURCE_MEM;
+
+	ret = platform_device_add_resources(pdev, &res, 1);
+	if (ret) {
+		dev_err(dev, "couldn't add resources to intel_xhci_usb_sw 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_xhci_usb_sw 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_xhci_usb_sw pdev\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+int xhci_ext_cap_init(struct xhci_hcd *xhci)
+{
+	void __iomem *base = &xhci->cap_regs->hc_capbase;
+	u32 offset, val;
+	int ret;
+
+	offset = xhci_find_next_ext_cap(base, 0, 0);
+
+	while (offset) {
+		val = readl(base + offset);
+
+		switch (XHCI_EXT_CAPS_ID(val)) {
+		case XHCI_EXT_CAPS_VENDOR_INTEL:
+			if (xhci->quirks & XHCI_INTEL_USB_ROLE_SW) {
+				ret = xhci_create_intel_xhci_sw_pdev(xhci,
+								     offset);
+				if (ret)
+					return ret;
+			}
+			break;
+		}
+		offset = xhci_find_next_ext_cap(base, offset, 0);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(xhci_ext_cap_init);

drivers/usb/host/xhci-ext-caps.h

···
 #define XHCI_EXT_CAPS_ROUTE	5
 /* IDs 6-9 reserved */
 #define XHCI_EXT_CAPS_DEBUG	10
+/* Vendor caps */
+#define XHCI_EXT_CAPS_VENDOR_INTEL	192
 /* USB Legacy Support Capability - section 7.1.1 */
 #define XHCI_HC_BIOS_OWNED	(1 << 16)
 #define XHCI_HC_OS_OWNED	(1 << 24)

drivers/usb/host/xhci-pci.c

···
 	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_USB_ROLE_SW;
 	}
 	if (pdev->vendor == PCI_VENDOR_ID_INTEL &&
 	    (pdev->device == PCI_DEVICE_ID_INTEL_CHERRYVIEW_XHCI ||
···
 		retval = -ENOMEM;
 		goto dealloc_usb2_hcd;
 	}
+
+	retval = xhci_ext_cap_init(xhci);
+	if (retval)
+		goto put_usb3_hcd;
 
 	retval = usb_add_hcd(xhci->shared_hcd, dev->irq,
 			IRQF_SHARED);

drivers/usb/host/xhci.h

···
 #define XHCI_ASMEDIA_MODIFY_FLOWCONTROL	(1 << 28)
 #define XHCI_HW_LPM_DISABLE	(1 << 29)
 #define XHCI_SUSPEND_DELAY	(1 << 30)
+#define XHCI_INTEL_USB_ROLE_SW	(1 << 31)
 
 	unsigned int		num_active_eps;
 	unsigned int		limit_active_eps;
···
 void xhci_init_driver(struct hc_driver *drv,
 		      const struct xhci_driver_overrides *over);
 int xhci_disable_slot(struct xhci_hcd *xhci, u32 slot_id);
+int xhci_ext_cap_init(struct xhci_hcd *xhci);
 
 int xhci_suspend(struct xhci_hcd *xhci, bool do_wakeup);
 int xhci_resume(struct xhci_hcd *xhci, bool hibernated);