[U-Boot] [UBOOT RFC PATCH 02/13] usb: gadget: udc-core: Add minimal udc-core from linux kernel

[Kishon Vijay Abraham I <kishon@ti.com>]

In order to support multiple USB device controllers in uboot,
udc-core is needed. udc-core also helps to cleanly link the USB peripheral
driver with the gadget driver. Hence Ported minimal udc-core from
linux kernel.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
---
 drivers/usb/gadget/Makefile   |   1 +
 drivers/usb/gadget/udc-core.c | 229 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 230 insertions(+)
 create mode 100644 drivers/usb/gadget/udc-core.c

diff --git a/drivers/usb/gadget/Makefile b/drivers/usb/gadget/Makefile
index 66becdc..74875a2 100644
--- a/drivers/usb/gadget/Makefile
+++ b/drivers/usb/gadget/Makefile
@@ -19,6 +19,7 @@ obj-$(CONFIG_USBDOWNLOAD_GADGET) += g_dnl.o
 obj-$(CONFIG_DFU_FUNCTION) += f_dfu.o
 obj-$(CONFIG_USB_GADGET_MASS_STORAGE) += f_mass_storage.o
 obj-$(CONFIG_CMD_FASTBOOT) += f_fastboot.o
+obj-y += udc-core.o
 endif
 ifdef CONFIG_USB_ETHER
 obj-y += ether.o
diff --git a/drivers/usb/gadget/udc-core.c b/drivers/usb/gadget/udc-core.c
new file mode 100644
index 0000000..bbe919c
--- /dev/null
+++ b/drivers/usb/gadget/udc-core.c
@@ -0,0 +1,229 @@
+/**
+ * udc-core.c - Core UDC Framework
+ *
+ * Copyright (C) 2014 Texas Instruments Incorporated - http://www.ti.com
+ *
+ * Author: Felipe Balbi <balbi@ti.com>
+ *
+ * Taken from Linux Kernel v3.16 (drivers/usb/gadget/udc-core.c) and ported
+ * to uboot.
+ *
+ * SPDX-License-Identifier:     GPL-2.0+
+ */
+
+#include <linux/compat.h>
+#include <malloc.h>
+#include <asm/cache.h>
+#include <common.h>
+
+#include <linux/usb/ch9.h>
+#include <linux/usb/gadget.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 list_head		list;
+};
+
+static LIST_HEAD(udc_list);
+
+void usb_gadget_set_state(struct usb_gadget *gadget,
+		enum usb_device_state state)
+{
+	gadget->state = state;
+}
+
+/**
+ * usb_gadget_udc_start - tells usb device controller to start up
+ * @gadget: The gadget we want to get started
+ * @driver: The driver we want to bind to @gadget
+ *
+ * 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_gadget *gadget,
+		struct usb_gadget_driver *driver)
+{
+	return gadget->ops->udc_start(gadget, 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_gadget *gadget,
+		struct usb_gadget_driver *driver)
+{
+	gadget->ops->udc_stop(gadget, driver);
+}
+
+/**
+ * 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 usb_gadget *gadget)
+{
+	struct usb_udc		*udc;
+	int			ret = -ENOMEM;
+
+	udc = kzalloc(sizeof(*udc), GFP_KERNEL);
+	if (!udc)
+		return ret;
+
+	udc->gadget = gadget;
+	list_add_tail(&udc->list, &udc_list);
+	usb_gadget_set_state(gadget, USB_STATE_NOTATTACHED);
+	return 0;
+}
+
+/**
+ * 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 usb_gadget *gadget)
+{
+	return usb_add_gadget_udc_release(gadget);
+}
+
+static void usb_gadget_remove_driver(struct usb_udc *udc)
+{
+	dev_dbg(&udc->dev, "unregistering UDC driver [%s]\n",
+			udc->gadget->name);
+	usb_gadget_disconnect(udc->gadget);
+	udc->driver->disconnect(udc->gadget);
+	udc->driver->unbind(udc->gadget);
+	usb_gadget_udc_stop(udc->gadget, NULL);
+
+	udc->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;
+	list_for_each_entry(udc, &udc_list, list)
+		if (udc->gadget == gadget)
+			goto found;
+
+	dev_err(gadget->dev.parent, "gadget not registered.\n");
+	return;
+
+found:
+	dev_vdbg(gadget->dev.parent, "unregistering gadget\n");
+
+	list_del(&udc->list);
+
+	if (udc->driver)
+		usb_gadget_remove_driver(udc);
+
+	kfree(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;
+
+	ret = driver->bind(udc->gadget);
+	if (ret)
+		goto err1;
+
+	ret = usb_gadget_udc_start(udc->gadget, driver);
+	if (ret) {
+		driver->unbind(udc->gadget);
+		goto err1;
+	}
+	usb_gadget_connect(udc->gadget);
+
+	return 0;
+err1:
+	if (ret != -EISNAM)
+		dev_err(&udc->dev, "failed to start %s: %d\n",
+			udc->driver->function, ret);
+	udc->driver = NULL;
+	return ret;
+}
+
+int usb_gadget_register_driver(struct usb_gadget_driver *driver)
+{
+	struct usb_udc		*udc = NULL;
+	int			ret;
+
+	if (!driver || !driver->bind || !driver->setup)
+		return -EINVAL;
+
+	list_for_each_entry(udc, &udc_list, list) {
+		/* For now we take the first one */
+		if (!udc->driver)
+			goto found;
+	}
+
+	debug("couldn't find an available UDC\n");
+	return -ENODEV;
+found:
+	ret = udc_bind_to_driver(udc, driver);
+	return ret;
+}
+
+int usb_gadget_unregister_driver(struct usb_gadget_driver *driver)
+{
+	struct usb_udc		*udc = NULL;
+	int			ret = -ENODEV;
+
+	if (!driver || !driver->unbind)
+		return -EINVAL;
+
+	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;
+		}
+
+	return ret;
+}
-- 
1.9.1