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

[Lukasz Majewski <l.majewski@samsung.com>]

Hi Kishon,

> In order to support multiple USB device controllers in uboot,
> udc-core is needed.

Is it? In u-boot at best only one UDC is operational at a time.

> udc-core also helps to cleanly link the USB
> peripheral driver with the gadget driver. Hence Ported minimal
> udc-core from linux kernel.

I'd appreciate the exact SHA for this udc-core.c code. And the SHA
should be from some already released mainline code (like final 3.16),
not any private branch nor linux-next.

> 
> 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+

It seems like the author is the same, but the GPL license is different:

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


/**                                                                                                                                                                                                              
 * udc.c - Core UDCFramework                                                                                                                                                                                    
 *                                                                                                                                                                                                               
 * Copyright (C) 2010 TexasInstruments                                                                                                                                                                          
 * 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.         

If Felipe don't mind then he should give you the permission to add + to
the GPL2.

> + */
> +
> +#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;
> +}



-- 
Best regards,

Lukasz Majewski

Samsung R&D Institute Poland (SRPOL) | Linux Platform Group