[patch 29/32] greybus: bridged phy usb driver

[Greg KH <gregkh@linuxfoundation.org>]

This driver implements the Greybus bridged phy USB class protocol.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/greybus/usb.c |  247 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 247 insertions(+)

--- /dev/null
+++ b/drivers/greybus/usb.c
@@ -0,0 +1,247 @@
+/*
+ * USB host driver for the Greybus "generic" USB module.
+ *
+ * Copyright 2014 Google Inc.
+ * Copyright 2014 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <linux/usb/hcd.h>
+
+#include "greybus.h"
+#include "gbphy.h"
+
+/* Greybus USB request types */
+#define GB_USB_TYPE_HCD_START		0x02
+#define GB_USB_TYPE_HCD_STOP		0x03
+#define GB_USB_TYPE_HUB_CONTROL		0x04
+
+struct gb_usb_hub_control_request {
+	__le16 typeReq;
+	__le16 wValue;
+	__le16 wIndex;
+	__le16 wLength;
+};
+
+struct gb_usb_hub_control_response {
+	u8 buf[0];
+};
+
+struct gb_usb_device {
+	struct gb_connection *connection;
+	struct gbphy_device *gbphy_dev;
+};
+
+static inline struct gb_usb_device *to_gb_usb_device(struct usb_hcd *hcd)
+{
+	return (struct gb_usb_device *)hcd->hcd_priv;
+}
+
+static inline struct usb_hcd *gb_usb_device_to_hcd(struct gb_usb_device *dev)
+{
+	return container_of((void *)dev, struct usb_hcd, hcd_priv);
+}
+
+static void hcd_stop(struct usb_hcd *hcd)
+{
+	struct gb_usb_device *dev = to_gb_usb_device(hcd);
+	int ret;
+
+	ret = gb_operation_sync(dev->connection, GB_USB_TYPE_HCD_STOP,
+				NULL, 0, NULL, 0);
+	if (ret)
+		dev_err(&dev->gbphy_dev->dev, "HCD stop failed '%d'\n", ret);
+}
+
+static int hcd_start(struct usb_hcd *hcd)
+{
+	struct usb_bus *bus = hcd_to_bus(hcd);
+	struct gb_usb_device *dev = to_gb_usb_device(hcd);
+	int ret;
+
+	ret = gb_operation_sync(dev->connection, GB_USB_TYPE_HCD_START,
+				NULL, 0, NULL, 0);
+	if (ret) {
+		dev_err(&dev->gbphy_dev->dev, "HCD start failed '%d'\n", ret);
+		return ret;
+	}
+
+	hcd->state = HC_STATE_RUNNING;
+	if (bus->root_hub)
+		usb_hcd_resume_root_hub(hcd);
+	return 0;
+}
+
+static int urb_enqueue(struct usb_hcd *hcd, struct urb *urb, gfp_t mem_flags)
+{
+	return -ENXIO;
+}
+
+static int urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
+{
+	return -ENXIO;
+}
+
+static int get_frame_number(struct usb_hcd *hcd)
+{
+	return 0;
+}
+
+static int hub_status_data(struct usb_hcd *hcd, char *buf)
+{
+	return 0;
+}
+
+static int hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue, u16 wIndex,
+		       char *buf, u16 wLength)
+{
+	struct gb_usb_device *dev = to_gb_usb_device(hcd);
+	struct gb_operation *operation;
+	struct gb_usb_hub_control_request *request;
+	struct gb_usb_hub_control_response *response;
+	size_t response_size;
+	int ret;
+
+	/* FIXME: handle unspecified lengths */
+	response_size = sizeof(*response) + wLength;
+
+	operation = gb_operation_create(dev->connection,
+					GB_USB_TYPE_HUB_CONTROL,
+					sizeof(*request),
+					response_size,
+					GFP_KERNEL);
+	if (!operation)
+		return -ENOMEM;
+
+	request = operation->request->payload;
+	request->typeReq = cpu_to_le16(typeReq);
+	request->wValue = cpu_to_le16(wValue);
+	request->wIndex = cpu_to_le16(wIndex);
+	request->wLength = cpu_to_le16(wLength);
+
+	ret = gb_operation_request_send_sync(operation);
+	if (ret)
+		goto out;
+
+	if (wLength) {
+		/* Greybus core has verified response size */
+		response = operation->response->payload;
+		memcpy(buf, response->buf, wLength);
+	}
+out:
+	gb_operation_put(operation);
+
+	return ret;
+}
+
+static struct hc_driver usb_gb_hc_driver = {
+	.description = "greybus-hcd",
+	.product_desc = "Greybus USB Host Controller",
+	.hcd_priv_size = sizeof(struct gb_usb_device),
+
+	.flags = HCD_USB2,
+
+	.start = hcd_start,
+	.stop = hcd_stop,
+
+	.urb_enqueue = urb_enqueue,
+	.urb_dequeue = urb_dequeue,
+
+	.get_frame_number = get_frame_number,
+	.hub_status_data = hub_status_data,
+	.hub_control = hub_control,
+};
+
+static int gb_usb_probe(struct gbphy_device *gbphy_dev,
+			const struct gbphy_device_id *id)
+{
+	struct gb_connection *connection;
+	struct device *dev = &gbphy_dev->dev;
+	struct gb_usb_device *gb_usb_dev;
+	struct usb_hcd *hcd;
+	int retval;
+
+	hcd = usb_create_hcd(&usb_gb_hc_driver, dev, dev_name(dev));
+	if (!hcd)
+		return -ENOMEM;
+
+	connection = gb_connection_create(gbphy_dev->bundle,
+					  le16_to_cpu(gbphy_dev->cport_desc->id),
+					  NULL);
+	if (IS_ERR(connection)) {
+		retval = PTR_ERR(connection);
+		goto exit_usb_put;
+	}
+
+	gb_usb_dev = to_gb_usb_device(hcd);
+	gb_usb_dev->connection = connection;
+	gb_connection_set_data(connection, gb_usb_dev);
+	gb_usb_dev->gbphy_dev = gbphy_dev;
+	gb_gbphy_set_data(gbphy_dev, gb_usb_dev);
+
+	hcd->has_tt = 1;
+
+	retval = gb_connection_enable(connection);
+	if (retval)
+		goto exit_connection_destroy;
+
+	/*
+	 * FIXME: The USB bridged-PHY protocol driver depends on changes to
+	 *        USB core which are not yet upstream.
+	 *
+	 *        Disable for now.
+	 */
+	if (1) {
+		dev_warn(dev, "USB protocol disabled\n");
+		retval = -EPROTONOSUPPORT;
+		goto exit_connection_disable;
+	}
+
+	retval = usb_add_hcd(hcd, 0, 0);
+	if (retval)
+		goto exit_connection_disable;
+
+	return 0;
+
+exit_connection_disable:
+	gb_connection_disable(connection);
+exit_connection_destroy:
+	gb_connection_destroy(connection);
+exit_usb_put:
+	usb_put_hcd(hcd);
+
+	return retval;
+}
+
+static void gb_usb_remove(struct gbphy_device *gbphy_dev)
+{
+	struct gb_usb_device *gb_usb_dev = gb_gbphy_get_data(gbphy_dev);
+	struct gb_connection *connection = gb_usb_dev->connection;
+	struct usb_hcd *hcd = gb_usb_device_to_hcd(gb_usb_dev);
+
+	usb_remove_hcd(hcd);
+	gb_connection_disable(connection);
+	gb_connection_destroy(connection);
+	usb_put_hcd(hcd);
+}
+
+static const struct gbphy_device_id gb_usb_id_table[] = {
+	{ GBPHY_PROTOCOL(GREYBUS_PROTOCOL_USB) },
+	{ },
+};
+MODULE_DEVICE_TABLE(gbphy, gb_usb_id_table);
+
+static struct gbphy_driver usb_driver = {
+	.name		= "usb",
+	.probe		= gb_usb_probe,
+	.remove		= gb_usb_remove,
+	.id_table	= gb_usb_id_table,
+};
+
+module_gbphy_driver(usb_driver);
+MODULE_LICENSE("GPL v2");