usb: host: xhci: add platform driver support

This adds a fairly simple xhci-platform driver support. Currently it is
used by the dwc3 driver for supporting host mode.

Signed-off-by: Sebastian Andrzej Siewior <[e-mail]>
Signed-off-by: Felipe Balbi <[e-mail]>
Signed-off-by: Sarah Sharp <[e-mail]>

drivers/usb/host/Kconfig

···
 	  To compile this driver as a module, choose M here: the
 	  module will be called xhci-hcd.
 
+config USB_XHCI_PLATFORM
+	tristate
+	depends on USB_XHCI_HCD
+
 config USB_XHCI_HCD_DEBUGGING
 	bool "Debugging for the xHCI host controller"
 	depends on USB_XHCI_HCD

drivers/usb/host/Makefile

···
 xhci-hcd-y += xhci-ring.o xhci-hub.o xhci-dbg.o
 xhci-hcd-$(CONFIG_PCI)	+= xhci-pci.o
 
+ifneq ($(CONFIG_USB_XHCI_PLATFORM), )
+	xhci-hcd-y		+= xhci-plat.o
+endif
+
 obj-$(CONFIG_USB_WHCI_HCD)	+= whci/
 
 obj-$(CONFIG_PCI)		+= pci-quirks.o

drivers/usb/host/xhci-plat.c

···
+/*
+ * xhci-plat.c - xHCI host controller driver platform Bus Glue.
+ *
+ * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com
+ * Author: Sebastian Andrzej Siewior <[e-mail]>
+ *
+ * A lot of code borrowed from the Linux xHCI driver.
+ *
+ * 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.
+ */
+
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#include "xhci.h"
+
+static void xhci_plat_quirks(struct device *dev, struct xhci_hcd *xhci)
+{
+	/*
+	 * As of now platform drivers don't provide MSI support so we ensure
+	 * here that the generic code does not try to make a pci_dev from our
+	 * dev struct in order to setup MSI
+	 */
+	xhci->quirks |= XHCI_BROKEN_MSI;
+}
+
+/* called during probe() after chip reset completes */
+static int xhci_plat_setup(struct usb_hcd *hcd)
+{
+	return xhci_gen_setup(hcd, xhci_plat_quirks);
+}
+
+static const struct hc_driver xhci_plat_xhci_driver = {
+	.description =		"xhci-hcd",
+	.product_desc =		"xHCI Host Controller",
+	.hcd_priv_size =	sizeof(struct xhci_hcd *),
+
+	/*
+	 * generic hardware linkage
+	 */
+	.irq =			xhci_irq,
+	.flags =		HCD_MEMORY | HCD_USB3 | HCD_SHARED,
+
+	/*
+	 * basic lifecycle operations
+	 */
+	.reset =		xhci_plat_setup,
+	.start =		xhci_run,
+	.stop =			xhci_stop,
+	.shutdown =		xhci_shutdown,
+
+	/*
+	 * managing i/o requests and associated device resources
+	 */
+	.urb_enqueue =		xhci_urb_enqueue,
+	.urb_dequeue =		xhci_urb_dequeue,
+	.alloc_dev =		xhci_alloc_dev,
+	.free_dev =		xhci_free_dev,
+	.alloc_streams =	xhci_alloc_streams,
+	.free_streams =		xhci_free_streams,
+	.add_endpoint =		xhci_add_endpoint,
+	.drop_endpoint =	xhci_drop_endpoint,
+	.endpoint_reset =	xhci_endpoint_reset,
+	.check_bandwidth =	xhci_check_bandwidth,
+	.reset_bandwidth =	xhci_reset_bandwidth,
+	.address_device =	xhci_address_device,
+	.update_hub_device =	xhci_update_hub_device,
+	.reset_device =		xhci_discover_or_reset_device,
+
+	/*
+	 * scheduling support
+	 */
+	.get_frame_number =	xhci_get_frame,
+
+	/* Root hub support */
+	.hub_control =		xhci_hub_control,
+	.hub_status_data =	xhci_hub_status_data,
+	.bus_suspend =		xhci_bus_suspend,
+	.bus_resume =		xhci_bus_resume,
+};
+
+static int xhci_plat_probe(struct platform_device *pdev)
+{
+	const struct hc_driver	*driver;
+	struct xhci_hcd		*xhci;
+	struct resource         *res;
+	struct usb_hcd		*hcd;
+	int			ret;
+	int			irq;
+
+	if (usb_disabled())
+		return -ENODEV;
+
+	driver = &xhci_plat_xhci_driver;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return -ENODEV;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -ENODEV;
+
+	hcd = usb_create_hcd(driver, &pdev->dev, dev_name(&pdev->dev));
+	if (!hcd)
+		return -ENOMEM;
+
+	hcd->rsrc_start = res->start;
+	hcd->rsrc_len = resource_size(res);
+
+	if (!request_mem_region(hcd->rsrc_start, hcd->rsrc_len,
+				driver->description)) {
+		dev_dbg(&pdev->dev, "controller already in use\n");
+		ret = -EBUSY;
+		goto put_hcd;
+	}
+
+	hcd->regs = ioremap(hcd->rsrc_start, hcd->rsrc_len);
+	if (!hcd->regs) {
+		dev_dbg(&pdev->dev, "error mapping memory\n");
+		ret = -EFAULT;
+		goto release_mem_region;
+	}
+
+	ret = usb_add_hcd(hcd, irq, IRQF_SHARED);
+	if (ret)
+		goto unmap_registers;
+
+	/* USB 2.0 roothub is stored in the platform_device now. */
+	hcd = dev_get_drvdata(&pdev->dev);
+	xhci = hcd_to_xhci(hcd);
+	xhci->shared_hcd = usb_create_shared_hcd(driver, &pdev->dev,
+			dev_name(&pdev->dev), hcd);
+	if (!xhci->shared_hcd) {
+		ret = -ENOMEM;
+		goto dealloc_usb2_hcd;
+	}
+
+	/*
+	 * Set the xHCI pointer before xhci_plat_setup() (aka hcd_driver.reset)
+	 * is called by usb_add_hcd().
+	 */
+	*((struct xhci_hcd **) xhci->shared_hcd->hcd_priv) = xhci;
+
+	ret = usb_add_hcd(xhci->shared_hcd, irq, IRQF_SHARED);
+	if (ret)
+		goto put_usb3_hcd;
+
+	return 0;
+
+put_usb3_hcd:
+	usb_put_hcd(xhci->shared_hcd);
+
+dealloc_usb2_hcd:
+	usb_remove_hcd(hcd);
+
+unmap_registers:
+	iounmap(hcd->regs);
+
+release_mem_region:
+	release_mem_region(hcd->rsrc_start, hcd->rsrc_len);
+
+put_hcd:
+	usb_put_hcd(hcd);
+
+	return ret;
+}
+
+static int xhci_plat_remove(struct platform_device *dev)
+{
+	struct usb_hcd	*hcd = platform_get_drvdata(dev);
+	struct xhci_hcd	*xhci = hcd_to_xhci(hcd);
+
+	usb_remove_hcd(xhci->shared_hcd);
+	usb_put_hcd(xhci->shared_hcd);
+
+	usb_remove_hcd(hcd);
+	iounmap(hcd->regs);
+	usb_put_hcd(hcd);
+	kfree(xhci);
+
+	return 0;
+}
+
+static struct platform_driver usb_xhci_driver = {
+	.probe	= xhci_plat_probe,
+	.remove	= xhci_plat_remove,
+	.driver	= {
+		.name = "xhci-hcd",
+	},
+};
+MODULE_ALIAS("platform:xhci-hcd");
+
+int xhci_register_plat(void)
+{
+	return platform_driver_register(&usb_xhci_driver);
+}
+
+void xhci_unregister_plat(void)
+{
+	platform_driver_unregister(&usb_xhci_driver);
+}

drivers/usb/host/xhci.c

···
 		printk(KERN_DEBUG "Problem registering PCI driver.");
 		return retval;
 	}
+	retval = xhci_register_plat();
+	if (retval < 0) {
+		printk(KERN_DEBUG "Problem registering platform driver.");
+		goto unreg_pci;
+	}
 	/*
 	 * Check the compiler generated sizes of structures that must be laid
 	 * out in specific ways for hardware access.
···
 	BUILD_BUG_ON(sizeof(struct xhci_run_regs) != (8+8*128)*32/8);
 	BUILD_BUG_ON(sizeof(struct xhci_doorbell_array) != 256*32/8);
 	return 0;
+unreg_pci:
+	xhci_unregister_pci();
+	return retval;
 }
 module_init(xhci_hcd_init);
 
 static void __exit xhci_hcd_cleanup(void)
 {
 	xhci_unregister_pci();
+	xhci_unregister_plat();
 }
 module_exit(xhci_hcd_cleanup);

drivers/usb/host/xhci.h

···
 static inline void xhci_unregister_pci(void) {}
 #endif
 
+#if defined(CONFIG_USB_XHCI_PLATFORM) \
+	|| defined(CONFIG_USB_XHCI_PLATFORM_MODULE)
+int xhci_register_plat(void);
+void xhci_unregister_plat(void);
+#else
+static inline int xhci_register_plat(void)
+{ return 0; }
+static inline void xhci_unregister_plat(void)
+{  }
+#endif
+
 /* xHCI host controller glue */
 typedef void (*xhci_get_quirks_t)(struct device *, struct xhci_hcd *);
 void xhci_quiesce(struct xhci_hcd *xhci);