usb.c

omap3 linux 2.6 用nocc去除了冗余代码

			return -ENODEV;
		if (udev->state == USB_STATE_SUSPENDED)
			return -EHOSTUNREACH;
		if (iface && iface->condition != USB_INTERFACE_BOUND)
			return -EINTR;
	}
	return 1;
}


static struct usb_device *match_device(struct usb_device *dev,
				       u16 vendor_id, u16 product_id)
{
	struct usb_device *ret_dev = NULL;
	int child;

	dev_dbg(&dev->dev, "check for vendor %04x, product %04x ...\n",
	    le16_to_cpu(dev->descriptor.idVendor),
	    le16_to_cpu(dev->descriptor.idProduct));

	/* see if this device matches */
	if ((vendor_id == le16_to_cpu(dev->descriptor.idVendor)) &&
	    (product_id == le16_to_cpu(dev->descriptor.idProduct))) {
		dev_dbg(&dev->dev, "matched this device!\n");
		ret_dev = usb_get_dev(dev);
		goto exit;
	}

	/* look through all of the children of this device */
	for (child = 0; child < dev->maxchild; ++child) {
		if (dev->children[child]) {
			usb_lock_device(dev->children[child]);
			ret_dev = match_device(dev->children[child],
					       vendor_id, product_id);
			usb_unlock_device(dev->children[child]);
			if (ret_dev)
				goto exit;
		}
	}
exit:
	return ret_dev;
}

/**
 * usb_find_device - find a specific usb device in the system
 * @vendor_id: the vendor id of the device to find
 * @product_id: the product id of the device to find
 *
 * Returns a pointer to a struct usb_device if such a specified usb
 * device is present in the system currently.  The usage count of the
 * device will be incremented if a device is found.  Make sure to call
 * usb_put_dev() when the caller is finished with the device.
 *
 * If a device with the specified vendor and product id is not found,
 * NULL is returned.
 */
struct usb_device *usb_find_device(u16 vendor_id, u16 product_id)
{
	struct list_head *buslist;
	struct usb_bus *bus;
	struct usb_device *dev = NULL;
	
	mutex_lock(&usb_bus_list_lock);
	for (buslist = usb_bus_list.next;
	     buslist != &usb_bus_list; 
	     buslist = buslist->next) {
		bus = container_of(buslist, struct usb_bus, bus_list);
		if (!bus->root_hub)
			continue;
		usb_lock_device(bus->root_hub);
		dev = match_device(bus->root_hub, vendor_id, product_id);
		usb_unlock_device(bus->root_hub);
		if (dev)
			goto exit;
	}
exit:
	mutex_unlock(&usb_bus_list_lock);
	return dev;
}

/**
 * usb_get_current_frame_number - return current bus frame number
 * @dev: the device whose bus is being queried
 *
 * Returns the current frame number for the USB host controller
 * used with the given USB device.  This can be used when scheduling
 * isochronous requests.
 *
 * Note that different kinds of host controller have different
 * "scheduling horizons".  While one type might support scheduling only
 * 32 frames into the future, others could support scheduling up to
 * 1024 frames into the future.
 */
int usb_get_current_frame_number(struct usb_device *dev)
{
	return usb_hcd_get_frame_number(dev);
}

/*-------------------------------------------------------------------*/
/*
 * __usb_get_extra_descriptor() finds a descriptor of specific type in the
 * extra field of the interface and endpoint descriptor structs.
 */

int __usb_get_extra_descriptor(char *buffer, unsigned size,
	unsigned char type, void **ptr)
{
	struct usb_descriptor_header *header;

	while (size >= sizeof(struct usb_descriptor_header)) {
		header = (struct usb_descriptor_header *)buffer;

		if (header->bLength < 2) {
			printk(KERN_ERR
				"%s: bogus descriptor, type %d length %d\n",
				usbcore_name,
				header->bDescriptorType, 
				header->bLength);
			return -1;
		}

		if (header->bDescriptorType == type) {
			*ptr = header;
			return 0;
		}

		buffer += header->bLength;
		size -= header->bLength;
	}
	return -1;
}

/**
 * usb_buffer_alloc - allocate dma-consistent buffer for URB_NO_xxx_DMA_MAP
 * @dev: device the buffer will be used with
 * @size: requested buffer size
 * @mem_flags: affect whether allocation may block
 * @dma: used to return DMA address of buffer
 *
 * Return value is either null (indicating no buffer could be allocated), or
 * the cpu-space pointer to a buffer that may be used to perform DMA to the
 * specified device.  Such cpu-space buffers are returned along with the DMA
 * address (through the pointer provided).
 *
 * These buffers are used with URB_NO_xxx_DMA_MAP set in urb->transfer_flags
 * to avoid behaviors like using "DMA bounce buffers", or tying down I/O
 * mapping hardware for long idle periods.  The implementation varies between
 * platforms, depending on details of how DMA will work to this device.
 * Using these buffers also helps prevent cacheline sharing problems on
 * architectures where CPU caches are not DMA-coherent.
 *
 * When the buffer is no longer used, free it with usb_buffer_free().
 */
void *usb_buffer_alloc(
	struct usb_device *dev,
	size_t size,
	gfp_t mem_flags,
	dma_addr_t *dma
)
{
	if (!dev || !dev->bus)
		return NULL;
	return hcd_buffer_alloc(dev->bus, size, mem_flags, dma);
}

/**
 * usb_buffer_free - free memory allocated with usb_buffer_alloc()
 * @dev: device the buffer was used with
 * @size: requested buffer size
 * @addr: CPU address of buffer
 * @dma: DMA address of buffer
 *
 * This reclaims an I/O buffer, letting it be reused.  The memory must have
 * been allocated using usb_buffer_alloc(), and the parameters must match
 * those provided in that allocation request. 
 */
void usb_buffer_free(
	struct usb_device *dev,
	size_t size,
	void *addr,
	dma_addr_t dma
)
{
	if (!dev || !dev->bus)
		return;
	if (!addr)
		return;
	hcd_buffer_free(dev->bus, size, addr, dma);
}

/**
 * usb_buffer_map - create DMA mapping(s) for an urb
 * @urb: urb whose transfer_buffer/setup_packet will be mapped
 *
 * Return value is either null (indicating no buffer could be mapped), or
 * the parameter.  URB_NO_TRANSFER_DMA_MAP and URB_NO_SETUP_DMA_MAP are
 * added to urb->transfer_flags if the operation succeeds.  If the device
 * is connected to this system through a non-DMA controller, this operation
 * always succeeds.
 *
 * This call would normally be used for an urb which is reused, perhaps
 * as the target of a large periodic transfer, with usb_buffer_dmasync()
 * calls to synchronize memory and dma state.
 *
 * Reverse the effect of this call with usb_buffer_unmap().
 */

/* XXX DISABLED, no users currently.  If you wish to re-enable this
 * XXX please determine whether the sync is to transfer ownership of
 * XXX the buffer from device to cpu or vice verse, and thusly use the
 * XXX appropriate _for_{cpu,device}() method.  -DaveM
 */

/**
 * usb_buffer_unmap - free DMA mapping(s) for an urb
 * @urb: urb whose transfer_buffer will be unmapped
 *
 * Reverses the effect of usb_buffer_map().
 */

/**
 * usb_buffer_map_sg - create scatterlist DMA mapping(s) for an endpoint
 * @dev: device to which the scatterlist will be mapped
 * @pipe: endpoint defining the mapping direction
 * @sg: the scatterlist to map
 * @nents: the number of entries in the scatterlist
 *
 * Return value is either < 0 (indicating no buffers could be mapped), or
 * the number of DMA mapping array entries in the scatterlist.
 *
 * The caller is responsible for placing the resulting DMA addresses from
 * the scatterlist into URB transfer buffer pointers, and for setting the
 * URB_NO_TRANSFER_DMA_MAP transfer flag in each of those URBs.
 *
 * Top I/O rates come from queuing URBs, instead of waiting for each one
 * to complete before starting the next I/O.   This is particularly easy
 * to do with scatterlists.  Just allocate and submit one URB for each DMA
 * mapping entry returned, stopping on the first error or when all succeed.
 * Better yet, use the usb_sg_*() calls, which do that (and more) for you.
 *
 * This call would normally be used when translating scatterlist requests,
 * rather than usb_buffer_map(), since on some hardware (with IOMMUs) it
 * may be able to coalesce mappings for improved I/O efficiency.
 *
 * Reverse the effect of this call with usb_buffer_unmap_sg().
 */
int usb_buffer_map_sg(const struct usb_device *dev, unsigned pipe,
		      struct scatterlist *sg, int nents)
{
	struct usb_bus		*bus;
	struct device		*controller;

	if (!dev
			|| usb_pipecontrol(pipe)
			|| !(bus = dev->bus)
			|| !(controller = bus->controller)
			|| !controller->dma_mask)
		return -1;

	// FIXME generic api broken like pci, can't report errors
	return dma_map_sg(controller, sg, nents,
			usb_pipein(pipe) ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
}

/* XXX DISABLED, no users currently.  If you wish to re-enable this
 * XXX please determine whether the sync is to transfer ownership of
 * XXX the buffer from device to cpu or vice verse, and thusly use the
 * XXX appropriate _for_{cpu,device}() method.  -DaveM
 */

/**
 * usb_buffer_unmap_sg - free DMA mapping(s) for a scatterlist
 * @dev: device to which the scatterlist will be mapped
 * @pipe: endpoint defining the mapping direction
 * @sg: the scatterlist to unmap
 * @n_hw_ents: the positive return value from usb_buffer_map_sg
 *
 * Reverses the effect of usb_buffer_map_sg().
 */
void usb_buffer_unmap_sg(const struct usb_device *dev, unsigned pipe,
			 struct scatterlist *sg, int n_hw_ents)
{
	struct usb_bus		*bus;
	struct device		*controller;

	if (!dev
			|| !(bus = dev->bus)
			|| !(controller = bus->controller)
			|| !controller->dma_mask)
		return;

	dma_unmap_sg(controller, sg, n_hw_ents,
			usb_pipein(pipe) ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
}

/* format to disable USB on kernel command line is: nousb */
__module_param_call("", nousb, param_set_bool, param_get_bool, &nousb, 0444);

/*
 * for external read access to <nousb>
 */
int usb_disabled(void)
{
	return nousb;
}

/*
 * Init
 */
static int __init usb_init(void)
{
	int retval;
	if (nousb) {
		pr_info("%s: USB support disabled\n", usbcore_name);
		return 0;
	}

	retval = ksuspend_usb_init();
	if (retval)
		goto out;
	retval = bus_register(&usb_bus_type);
	if (retval) 
		goto bus_register_failed;
	retval = usb_host_init();
	if (retval)
		goto host_init_failed;
	retval = usb_major_init();
	if (retval)
		goto major_init_failed;
	retval = usb_register(&usbfs_driver);
	if (retval)
		goto driver_register_failed;
	retval = usb_devio_init();
	if (retval)
		goto usb_devio_init_failed;
	retval = usbfs_init();
	if (retval)
		goto fs_init_failed;
	retval = usb_hub_init();
	if (retval)
		goto hub_init_failed;
	retval = usb_register_device_driver(&usb_generic_driver, THIS_MODULE);
	if (!retval)
		goto out;

	usb_hub_cleanup();
hub_init_failed:
	usbfs_cleanup();
fs_init_failed:
	usb_devio_cleanup();
usb_devio_init_failed:
	usb_deregister(&usbfs_driver);
driver_register_failed:
	usb_major_cleanup();
major_init_failed:
	usb_host_cleanup();
host_init_failed:
	bus_unregister(&usb_bus_type);
bus_register_failed:
	ksuspend_usb_cleanup();
out:
	return retval;
}

/*
 * Cleanup
 */
static void __exit usb_exit(void)
{
	/* This will matter if shutdown/reboot does exitcalls. */
	if (nousb)
		return;

	usb_deregister_device_driver(&usb_generic_driver);
	usb_major_cleanup();
	usbfs_cleanup();
	usb_deregister(&usbfs_driver);
	usb_devio_cleanup();
	usb_hub_cleanup();
	usb_host_cleanup();
	bus_unregister(&usb_bus_type);
	ksuspend_usb_cleanup();
}

subsys_initcall(usb_init);
module_exit(usb_exit);

/*
 * USB may be built into the kernel or be built as modules.
 * These symbols are exported for device (or host controller)
 * driver modules to use.
 */

EXPORT_SYMBOL(usb_disabled);

EXPORT_SYMBOL_GPL(usb_get_intf);
EXPORT_SYMBOL_GPL(usb_put_intf);

EXPORT_SYMBOL(usb_put_dev);
EXPORT_SYMBOL(usb_get_dev);
EXPORT_SYMBOL(usb_hub_tt_clear_buffer);

EXPORT_SYMBOL(usb_lock_device_for_reset);

EXPORT_SYMBOL(usb_find_interface);
EXPORT_SYMBOL(usb_ifnum_to_if);
EXPORT_SYMBOL(usb_altnum_to_altsetting);

EXPORT_SYMBOL(__usb_get_extra_descriptor);

EXPORT_SYMBOL(usb_find_device);
EXPORT_SYMBOL(usb_get_current_frame_number);

EXPORT_SYMBOL(usb_buffer_alloc);
EXPORT_SYMBOL(usb_buffer_free);


EXPORT_SYMBOL(usb_buffer_map_sg);
EXPORT_SYMBOL(usb_buffer_unmap_sg);

MODULE_LICENSE("GPL");