usb: gadget: udc: add udc-core from linux kernel to u-boot

Added udc-core.c from linux kernel 3.19-rc1 (97bf6af1f9) to u-boot.
This will be adapted to work with u-boot in the
following patches.
Adding support for udc will help to seamlessly port dwc3 driver from
linux kernel to u-boot (since dwc3 uses udc-core) and it'll also help
to add support for multiple gadget controllers to be functional at the
same time.
All other gadget drivers can also be adapted to use udc-core.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Reviewed-by: Lukasz Majewski <l.majewski@samsung.com>

drivers/usb/gadget/udc/Makefile

@@ -0,0 +1,4 @@
+#
+# USB peripheral controller drivers
+#
+obj-$(CONFIG_USB_GADGET)	+= udc-core.o

drivers/usb/gadget/udc/udc-core.c

@@ -0,0 +1,637 @@
+/**
+ * udc.c - Core UDC Framework
+ *
+ * Copyright (C) 2010 Texas Instruments
+ * Author: Felipe Balbi <balbi@ti.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2  of
+ * the License 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.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/list.h>
+#include <linux/err.h>
+#include <linux/dma-mapping.h>
+#include <linux/workqueue.h>
+
+#include <linux/usb/ch9.h>
+#include <linux/usb/gadget.h>
+#include <linux/usb.h>
+
+/**
+ * struct usb_udc - describes one usb device controller
+ * @driver - the gadget driver pointer. For use by the class code
+ * @dev - the child device to the actual controller
+ * @gadget - the gadget. For use by the class code
+ * @list - for use by the udc class driver
+ *
+ * This represents the internal data structure which is used by the UDC-class
+ * to hold information about udc driver and gadget together.
+ */
+struct usb_udc {
+	struct usb_gadget_driver	*driver;
+	struct usb_gadget		*gadget;
+	struct device			dev;
+	struct list_head		list;
+};
+
+static struct class *udc_class;
+static LIST_HEAD(udc_list);
+static DEFINE_MUTEX(udc_lock);
+
+/* ------------------------------------------------------------------------- */
+
+#ifdef	CONFIG_HAS_DMA
+
+int usb_gadget_map_request(struct usb_gadget *gadget,
+		struct usb_request *req, int is_in)
+{
+	if (req->length == 0)
+		return 0;
+
+	if (req->num_sgs) {
+		int     mapped;
+
+		mapped = dma_map_sg(&gadget->dev, req->sg, req->num_sgs,
+				is_in ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
+		if (mapped == 0) {
+			dev_err(&gadget->dev, "failed to map SGs\n");
+			return -EFAULT;
+		}
+
+		req->num_mapped_sgs = mapped;
+	} else {
+		req->dma = dma_map_single(&gadget->dev, req->buf, req->length,
+				is_in ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
+
+		if (dma_mapping_error(&gadget->dev, req->dma)) {
+			dev_err(&gadget->dev, "failed to map buffer\n");
+			return -EFAULT;
+		}
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(usb_gadget_map_request);
+
+void usb_gadget_unmap_request(struct usb_gadget *gadget,
+		struct usb_request *req, int is_in)
+{
+	if (req->length == 0)
+		return;
+
+	if (req->num_mapped_sgs) {
+		dma_unmap_sg(&gadget->dev, req->sg, req->num_mapped_sgs,
+				is_in ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
+
+		req->num_mapped_sgs = 0;
+	} else {
+		dma_unmap_single(&gadget->dev, req->dma, req->length,
+				is_in ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
+	}
+}
+EXPORT_SYMBOL_GPL(usb_gadget_unmap_request);
+
+#endif	/* CONFIG_HAS_DMA */
+
+/* ------------------------------------------------------------------------- */
+
+/**
+ * usb_gadget_giveback_request - give the request back to the gadget layer
+ * Context: in_interrupt()
+ *
+ * This is called by device controller drivers in order to return the
+ * completed request back to the gadget layer.
+ */
+void usb_gadget_giveback_request(struct usb_ep *ep,
+		struct usb_request *req)
+{
+	if (likely(req->status == 0))
+		usb_led_activity(USB_LED_EVENT_GADGET);
+
+	req->complete(ep, req);
+}
+EXPORT_SYMBOL_GPL(usb_gadget_giveback_request);
+
+/* ------------------------------------------------------------------------- */
+
+static void usb_gadget_state_work(struct work_struct *work)
+{
+	struct usb_gadget	*gadget = work_to_gadget(work);
+	struct usb_udc		*udc = NULL;
+
+	mutex_lock(&udc_lock);
+	list_for_each_entry(udc, &udc_list, list)
+		if (udc->gadget == gadget)
+			goto found;
+	mutex_unlock(&udc_lock);
+
+	return;
+
+found:
+	mutex_unlock(&udc_lock);
+
+	sysfs_notify(&udc->dev.kobj, NULL, "state");
+}
+
+void usb_gadget_set_state(struct usb_gadget *gadget,
+		enum usb_device_state state)
+{
+	gadget->state = state;
+	schedule_work(&gadget->work);
+}
+EXPORT_SYMBOL_GPL(usb_gadget_set_state);
+
+/* ------------------------------------------------------------------------- */
+
+/**
+ * usb_gadget_udc_reset - notifies the udc core that bus reset occurs
+ * @gadget: The gadget which bus reset occurs
+ * @driver: The gadget driver we want to notify
+ *
+ * If the udc driver has bus reset handler, it needs to call this when the bus
+ * reset occurs, it notifies the gadget driver that the bus reset occurs as
+ * well as updates gadget state.
+ */
+void usb_gadget_udc_reset(struct usb_gadget *gadget,
+		struct usb_gadget_driver *driver)
+{
+	driver->reset(gadget);
+	usb_gadget_set_state(gadget, USB_STATE_DEFAULT);
+}
+EXPORT_SYMBOL_GPL(usb_gadget_udc_reset);
+
+/**
+ * usb_gadget_udc_start - tells usb device controller to start up
+ * @udc: The UDC to be started
+ *
+ * This call is issued by the UDC Class driver when it's about
+ * to register a gadget driver to the device controller, before
+ * calling gadget driver's bind() method.
+ *
+ * It allows the controller to be powered off until strictly
+ * necessary to have it powered on.
+ *
+ * Returns zero on success, else negative errno.
+ */
+static inline int usb_gadget_udc_start(struct usb_udc *udc)
+{
+	return udc->gadget->ops->udc_start(udc->gadget, udc->driver);
+}
+
+/**
+ * usb_gadget_udc_stop - tells usb device controller we don't need it anymore
+ * @gadget: The device we want to stop activity
+ * @driver: The driver to unbind from @gadget
+ *
+ * This call is issued by the UDC Class driver after calling
+ * gadget driver's unbind() method.
+ *
+ * The details are implementation specific, but it can go as
+ * far as powering off UDC completely and disable its data
+ * line pullups.
+ */
+static inline void usb_gadget_udc_stop(struct usb_udc *udc)
+{
+	udc->gadget->ops->udc_stop(udc->gadget);
+}
+
+/**
+ * usb_udc_release - release the usb_udc struct
+ * @dev: the dev member within usb_udc
+ *
+ * This is called by driver's core in order to free memory once the last
+ * reference is released.
+ */
+static void usb_udc_release(struct device *dev)
+{
+	struct usb_udc *udc;
+
+	udc = container_of(dev, struct usb_udc, dev);
+	dev_dbg(dev, "releasing '%s'\n", dev_name(dev));
+	kfree(udc);
+}
+
+static const struct attribute_group *usb_udc_attr_groups[];
+
+static void usb_udc_nop_release(struct device *dev)
+{
+	dev_vdbg(dev, "%s\n", __func__);
+}
+
+/**
+ * usb_add_gadget_udc_release - adds a new gadget to the udc class driver list
+ * @parent: the parent device to this udc. Usually the controller driver's
+ * device.
+ * @gadget: the gadget to be added to the list.
+ * @release: a gadget release function.
+ *
+ * Returns zero on success, negative errno otherwise.
+ */
+int usb_add_gadget_udc_release(struct device *parent, struct usb_gadget *gadget,
+		void (*release)(struct device *dev))
+{
+	struct usb_udc		*udc;
+	int			ret = -ENOMEM;
+
+	udc = kzalloc(sizeof(*udc), GFP_KERNEL);
+	if (!udc)
+		goto err1;
+
+	dev_set_name(&gadget->dev, "gadget");
+	INIT_WORK(&gadget->work, usb_gadget_state_work);
+	gadget->dev.parent = parent;
+
+#ifdef	CONFIG_HAS_DMA
+	dma_set_coherent_mask(&gadget->dev, parent->coherent_dma_mask);
+	gadget->dev.dma_parms = parent->dma_parms;
+	gadget->dev.dma_mask = parent->dma_mask;
+#endif
+
+	if (release)
+		gadget->dev.release = release;
+	else
+		gadget->dev.release = usb_udc_nop_release;
+
+	ret = device_register(&gadget->dev);
+	if (ret)
+		goto err2;
+
+	device_initialize(&udc->dev);
+	udc->dev.release = usb_udc_release;
+	udc->dev.class = udc_class;
+	udc->dev.groups = usb_udc_attr_groups;
+	udc->dev.parent = parent;
+	ret = dev_set_name(&udc->dev, "%s", kobject_name(&parent->kobj));
+	if (ret)
+		goto err3;
+
+	udc->gadget = gadget;
+
+	mutex_lock(&udc_lock);
+	list_add_tail(&udc->list, &udc_list);
+
+	ret = device_add(&udc->dev);
+	if (ret)
+		goto err4;
+
+	usb_gadget_set_state(gadget, USB_STATE_NOTATTACHED);
+
+	mutex_unlock(&udc_lock);
+
+	return 0;
+
+err4:
+	list_del(&udc->list);
+	mutex_unlock(&udc_lock);
+
+err3:
+	put_device(&udc->dev);
+
+err2:
+	put_device(&gadget->dev);
+	kfree(udc);
+
+err1:
+	return ret;
+}
+EXPORT_SYMBOL_GPL(usb_add_gadget_udc_release);
+
+/**
+ * usb_add_gadget_udc - adds a new gadget to the udc class driver list
+ * @parent: the parent device to this udc. Usually the controller
+ * driver's device.
+ * @gadget: the gadget to be added to the list
+ *
+ * Returns zero on success, negative errno otherwise.
+ */
+int usb_add_gadget_udc(struct device *parent, struct usb_gadget *gadget)
+{
+	return usb_add_gadget_udc_release(parent, gadget, NULL);
+}
+EXPORT_SYMBOL_GPL(usb_add_gadget_udc);
+
+static void usb_gadget_remove_driver(struct usb_udc *udc)
+{
+	dev_dbg(&udc->dev, "unregistering UDC driver [%s]\n",
+			udc->driver->function);
+
+	kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE);
+
+	usb_gadget_disconnect(udc->gadget);
+	udc->driver->disconnect(udc->gadget);
+	udc->driver->unbind(udc->gadget);
+	usb_gadget_udc_stop(udc);
+
+	udc->driver = NULL;
+	udc->dev.driver = NULL;
+	udc->gadget->dev.driver = NULL;
+}
+
+/**
+ * usb_del_gadget_udc - deletes @udc from udc_list
+ * @gadget: the gadget to be removed.
+ *
+ * This, will call usb_gadget_unregister_driver() if
+ * the @udc is still busy.
+ */
+void usb_del_gadget_udc(struct usb_gadget *gadget)
+{
+	struct usb_udc		*udc = NULL;
+
+	mutex_lock(&udc_lock);
+	list_for_each_entry(udc, &udc_list, list)
+		if (udc->gadget == gadget)
+			goto found;
+
+	dev_err(gadget->dev.parent, "gadget not registered.\n");
+	mutex_unlock(&udc_lock);
+
+	return;
+
+found:
+	dev_vdbg(gadget->dev.parent, "unregistering gadget\n");
+
+	list_del(&udc->list);
+	mutex_unlock(&udc_lock);
+
+	if (udc->driver)
+		usb_gadget_remove_driver(udc);
+
+	kobject_uevent(&udc->dev.kobj, KOBJ_REMOVE);
+	flush_work(&gadget->work);
+	device_unregister(&udc->dev);
+	device_unregister(&gadget->dev);
+}
+EXPORT_SYMBOL_GPL(usb_del_gadget_udc);
+
+/* ------------------------------------------------------------------------- */
+
+static int udc_bind_to_driver(struct usb_udc *udc, struct usb_gadget_driver *driver)
+{
+	int ret;
+
+	dev_dbg(&udc->dev, "registering UDC driver [%s]\n",
+			driver->function);
+
+	udc->driver = driver;
+	udc->dev.driver = &driver->driver;
+	udc->gadget->dev.driver = &driver->driver;
+
+	ret = driver->bind(udc->gadget, driver);
+	if (ret)
+		goto err1;
+	ret = usb_gadget_udc_start(udc);
+	if (ret) {
+		driver->unbind(udc->gadget);
+		goto err1;
+	}
+	usb_gadget_connect(udc->gadget);
+
+	kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE);
+	return 0;
+err1:
+	if (ret != -EISNAM)
+		dev_err(&udc->dev, "failed to start %s: %d\n",
+			udc->driver->function, ret);
+	udc->driver = NULL;
+	udc->dev.driver = NULL;
+	udc->gadget->dev.driver = NULL;
+	return ret;
+}
+
+int usb_udc_attach_driver(const char *name, struct usb_gadget_driver *driver)
+{
+	struct usb_udc *udc = NULL;
+	int ret = -ENODEV;
+
+	mutex_lock(&udc_lock);
+	list_for_each_entry(udc, &udc_list, list) {
+		ret = strcmp(name, dev_name(&udc->dev));
+		if (!ret)
+			break;
+	}
+	if (ret) {
+		ret = -ENODEV;
+		goto out;
+	}
+	if (udc->driver) {
+		ret = -EBUSY;
+		goto out;
+	}
+	ret = udc_bind_to_driver(udc, driver);
+out:
+	mutex_unlock(&udc_lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(usb_udc_attach_driver);
+
+int usb_gadget_probe_driver(struct usb_gadget_driver *driver)
+{
+	struct usb_udc		*udc = NULL;
+	int			ret;
+
+	if (!driver || !driver->bind || !driver->setup)
+		return -EINVAL;
+
+	mutex_lock(&udc_lock);
+	list_for_each_entry(udc, &udc_list, list) {
+		/* For now we take the first one */
+		if (!udc->driver)
+			goto found;
+	}
+
+	pr_debug("couldn't find an available UDC\n");
+	mutex_unlock(&udc_lock);
+	return -ENODEV;
+found:
+	ret = udc_bind_to_driver(udc, driver);
+	mutex_unlock(&udc_lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(usb_gadget_probe_driver);
+
+int usb_gadget_unregister_driver(struct usb_gadget_driver *driver)
+{
+	struct usb_udc		*udc = NULL;
+	int			ret = -ENODEV;
+
+	if (!driver || !driver->unbind)
+		return -EINVAL;
+
+	mutex_lock(&udc_lock);
+	list_for_each_entry(udc, &udc_list, list)
+		if (udc->driver == driver) {
+			usb_gadget_remove_driver(udc);
+			usb_gadget_set_state(udc->gadget,
+					USB_STATE_NOTATTACHED);
+			ret = 0;
+			break;
+		}
+
+	mutex_unlock(&udc_lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(usb_gadget_unregister_driver);
+
+/* ------------------------------------------------------------------------- */
+
+static ssize_t usb_udc_srp_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t n)
+{
+	struct usb_udc		*udc = container_of(dev, struct usb_udc, dev);
+
+	if (sysfs_streq(buf, "1"))
+		usb_gadget_wakeup(udc->gadget);
+
+	return n;
+}
+static DEVICE_ATTR(srp, S_IWUSR, NULL, usb_udc_srp_store);
+
+static ssize_t usb_udc_softconn_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t n)
+{
+	struct usb_udc		*udc = container_of(dev, struct usb_udc, dev);
+
+	if (!udc->driver) {
+		dev_err(dev, "soft-connect without a gadget driver\n");
+		return -EOPNOTSUPP;
+	}
+
+	if (sysfs_streq(buf, "connect")) {
+		usb_gadget_udc_start(udc);
+		usb_gadget_connect(udc->gadget);
+	} else if (sysfs_streq(buf, "disconnect")) {
+		usb_gadget_disconnect(udc->gadget);
+		udc->driver->disconnect(udc->gadget);
+		usb_gadget_udc_stop(udc);
+	} else {
+		dev_err(dev, "unsupported command '%s'\n", buf);
+		return -EINVAL;
+	}
+
+	return n;
+}
+static DEVICE_ATTR(soft_connect, S_IWUSR, NULL, usb_udc_softconn_store);
+
+static ssize_t state_show(struct device *dev, struct device_attribute *attr,
+			  char *buf)
+{
+	struct usb_udc		*udc = container_of(dev, struct usb_udc, dev);
+	struct usb_gadget	*gadget = udc->gadget;
+
+	return sprintf(buf, "%s\n", usb_state_string(gadget->state));
+}
+static DEVICE_ATTR_RO(state);
+
+#define USB_UDC_SPEED_ATTR(name, param)					\
+ssize_t name##_show(struct device *dev,					\
+		struct device_attribute *attr, char *buf)		\
+{									\
+	struct usb_udc *udc = container_of(dev, struct usb_udc, dev);	\
+	return snprintf(buf, PAGE_SIZE, "%s\n",				\
+			usb_speed_string(udc->gadget->param));		\
+}									\
+static DEVICE_ATTR_RO(name)
+
+static USB_UDC_SPEED_ATTR(current_speed, speed);
+static USB_UDC_SPEED_ATTR(maximum_speed, max_speed);
+
+#define USB_UDC_ATTR(name)					\
+ssize_t name##_show(struct device *dev,				\
+		struct device_attribute *attr, char *buf)	\
+{								\
+	struct usb_udc		*udc = container_of(dev, struct usb_udc, dev); \
+	struct usb_gadget	*gadget = udc->gadget;		\
+								\
+	return snprintf(buf, PAGE_SIZE, "%d\n", gadget->name);	\
+}								\
+static DEVICE_ATTR_RO(name)
+
+static USB_UDC_ATTR(is_otg);
+static USB_UDC_ATTR(is_a_peripheral);
+static USB_UDC_ATTR(b_hnp_enable);
+static USB_UDC_ATTR(a_hnp_support);
+static USB_UDC_ATTR(a_alt_hnp_support);
+
+static struct attribute *usb_udc_attrs[] = {
+	&dev_attr_srp.attr,
+	&dev_attr_soft_connect.attr,
+	&dev_attr_state.attr,
+	&dev_attr_current_speed.attr,
+	&dev_attr_maximum_speed.attr,
+
+	&dev_attr_is_otg.attr,
+	&dev_attr_is_a_peripheral.attr,
+	&dev_attr_b_hnp_enable.attr,
+	&dev_attr_a_hnp_support.attr,
+	&dev_attr_a_alt_hnp_support.attr,
+	NULL,
+};
+
+static const struct attribute_group usb_udc_attr_group = {
+	.attrs = usb_udc_attrs,
+};
+
+static const struct attribute_group *usb_udc_attr_groups[] = {
+	&usb_udc_attr_group,
+	NULL,
+};
+
+static int usb_udc_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	struct usb_udc		*udc = container_of(dev, struct usb_udc, dev);
+	int			ret;
+
+	ret = add_uevent_var(env, "USB_UDC_NAME=%s", udc->gadget->name);
+	if (ret) {
+		dev_err(dev, "failed to add uevent USB_UDC_NAME\n");
+		return ret;
+	}
+
+	if (udc->driver) {
+		ret = add_uevent_var(env, "USB_UDC_DRIVER=%s",
+				udc->driver->function);
+		if (ret) {
+			dev_err(dev, "failed to add uevent USB_UDC_DRIVER\n");
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int __init usb_udc_init(void)
+{
+	udc_class = class_create(THIS_MODULE, "udc");
+	if (IS_ERR(udc_class)) {
+		pr_err("failed to create udc class --> %ld\n",
+				PTR_ERR(udc_class));
+		return PTR_ERR(udc_class);
+	}
+
+	udc_class->dev_uevent = usb_udc_uevent;
+	return 0;
+}
+subsys_initcall(usb_udc_init);
+
+static void __exit usb_udc_exit(void)
+{
+	class_destroy(udc_class);
+}
+module_exit(usb_udc_exit);
+
+MODULE_DESCRIPTION("UDC Framework");
+MODULE_AUTHOR("Felipe Balbi <balbi@ti.com>");
+MODULE_LICENSE("GPL v2");