kernel-ark/drivers/usb/core/usb.c
David Brownell fbf54dd320 USB: usb/dma doc updates
This patch updates some of the documentation about DMA buffer management
for USB, and ways to avoid extra copying.  Our understanding of the issues
has improved over time.

 - Most drivers should *avoid* the dma-coherent allocators.  There are
   a few exceptions (like the HID driver).

 - Some methods are currently commented out; it seems folk writing
   USB drivers aren't doing performance tuning at that level yet.

 - Just avoid highmem; there's no good way to pass an "I can do highmem
   DMA" capability through a driver stack.  This is easy, everything
   already avoids highmem.  But it'd be nice if x86_32 systems with much
   physical memory could use it directly with network adapters and mass
   storage devices.  (Patch, anyone?)

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-12 16:34:42 -07:00

985 lines
28 KiB
C

/*
* drivers/usb/core/usb.c
*
* (C) Copyright Linus Torvalds 1999
* (C) Copyright Johannes Erdfelt 1999-2001
* (C) Copyright Andreas Gal 1999
* (C) Copyright Gregory P. Smith 1999
* (C) Copyright Deti Fliegl 1999 (new USB architecture)
* (C) Copyright Randy Dunlap 2000
* (C) Copyright David Brownell 2000-2004
* (C) Copyright Yggdrasil Computing, Inc. 2000
* (usb_device_id matching changes by Adam J. Richter)
* (C) Copyright Greg Kroah-Hartman 2002-2003
*
* NOTE! This is not actually a driver at all, rather this is
* just a collection of helper routines that implement the
* generic USB things that the real drivers can use..
*
* Think of this as a "USB library" rather than anything else.
* It should be considered a slave, with no callbacks. Callbacks
* are evil.
*/
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/string.h>
#include <linux/bitops.h>
#include <linux/slab.h>
#include <linux/interrupt.h> /* for in_interrupt() */
#include <linux/kmod.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/errno.h>
#include <linux/usb.h>
#include <linux/mutex.h>
#include <linux/workqueue.h>
#include <asm/io.h>
#include <asm/scatterlist.h>
#include <linux/mm.h>
#include <linux/dma-mapping.h>
#include "hcd.h"
#include "usb.h"
const char *usbcore_name = "usbcore";
static int nousb; /* Disable USB when built into kernel image */
/* Workqueue for autosuspend and for remote wakeup of root hubs */
struct workqueue_struct *ksuspend_usb_wq;
#ifdef CONFIG_USB_SUSPEND
static int usb_autosuspend_delay = 2; /* Default delay value,
* in seconds */
module_param_named(autosuspend, usb_autosuspend_delay, int, 0644);
MODULE_PARM_DESC(autosuspend, "default autosuspend delay");
#else
#define usb_autosuspend_delay 0
#endif
/**
* usb_ifnum_to_if - get the interface object with a given interface number
* @dev: the device whose current configuration is considered
* @ifnum: the desired interface
*
* This walks the device descriptor for the currently active configuration
* and returns a pointer to the interface with that particular interface
* number, or null.
*
* Note that configuration descriptors are not required to assign interface
* numbers sequentially, so that it would be incorrect to assume that
* the first interface in that descriptor corresponds to interface zero.
* This routine helps device drivers avoid such mistakes.
* However, you should make sure that you do the right thing with any
* alternate settings available for this interfaces.
*
* Don't call this function unless you are bound to one of the interfaces
* on this device or you have locked the device!
*/
struct usb_interface *usb_ifnum_to_if(const struct usb_device *dev,
unsigned ifnum)
{
struct usb_host_config *config = dev->actconfig;
int i;
if (!config)
return NULL;
for (i = 0; i < config->desc.bNumInterfaces; i++)
if (config->interface[i]->altsetting[0]
.desc.bInterfaceNumber == ifnum)
return config->interface[i];
return NULL;
}
/**
* usb_altnum_to_altsetting - get the altsetting structure with a given
* alternate setting number.
* @intf: the interface containing the altsetting in question
* @altnum: the desired alternate setting number
*
* This searches the altsetting array of the specified interface for
* an entry with the correct bAlternateSetting value and returns a pointer
* to that entry, or null.
*
* Note that altsettings need not be stored sequentially by number, so
* it would be incorrect to assume that the first altsetting entry in
* the array corresponds to altsetting zero. This routine helps device
* drivers avoid such mistakes.
*
* Don't call this function unless you are bound to the intf interface
* or you have locked the device!
*/
struct usb_host_interface *usb_altnum_to_altsetting(const struct usb_interface *intf,
unsigned int altnum)
{
int i;
for (i = 0; i < intf->num_altsetting; i++) {
if (intf->altsetting[i].desc.bAlternateSetting == altnum)
return &intf->altsetting[i];
}
return NULL;
}
struct find_interface_arg {
int minor;
struct usb_interface *interface;
};
static int __find_interface(struct device * dev, void * data)
{
struct find_interface_arg *arg = data;
struct usb_interface *intf;
/* can't look at usb devices, only interfaces */
if (is_usb_device(dev))
return 0;
intf = to_usb_interface(dev);
if (intf->minor != -1 && intf->minor == arg->minor) {
arg->interface = intf;
return 1;
}
return 0;
}
/**
* usb_find_interface - find usb_interface pointer for driver and device
* @drv: the driver whose current configuration is considered
* @minor: the minor number of the desired device
*
* This walks the driver device list and returns a pointer to the interface
* with the matching minor. Note, this only works for devices that share the
* USB major number.
*/
struct usb_interface *usb_find_interface(struct usb_driver *drv, int minor)
{
struct find_interface_arg argb;
int retval;
argb.minor = minor;
argb.interface = NULL;
/* eat the error, it will be in argb.interface */
retval = driver_for_each_device(&drv->drvwrap.driver, NULL, &argb,
__find_interface);
return argb.interface;
}
/**
* usb_release_dev - free a usb device structure when all users of it are finished.
* @dev: device that's been disconnected
*
* Will be called only by the device core when all users of this usb device are
* done.
*/
static void usb_release_dev(struct device *dev)
{
struct usb_device *udev;
udev = to_usb_device(dev);
usb_destroy_configuration(udev);
usb_put_hcd(bus_to_hcd(udev->bus));
kfree(udev->product);
kfree(udev->manufacturer);
kfree(udev->serial);
kfree(udev);
}
struct device_type usb_device_type = {
.name = "usb_device",
.release = usb_release_dev,
};
#ifdef CONFIG_PM
static int ksuspend_usb_init(void)
{
/* This workqueue is supposed to be both freezable and
* singlethreaded. Its job doesn't justify running on more
* than one CPU.
*/
ksuspend_usb_wq = create_freezeable_workqueue("ksuspend_usbd");
if (!ksuspend_usb_wq)
return -ENOMEM;
return 0;
}
static void ksuspend_usb_cleanup(void)
{
destroy_workqueue(ksuspend_usb_wq);
}
#else
#define ksuspend_usb_init() 0
#define ksuspend_usb_cleanup() do {} while (0)
#endif /* CONFIG_PM */
/**
* usb_alloc_dev - usb device constructor (usbcore-internal)
* @parent: hub to which device is connected; null to allocate a root hub
* @bus: bus used to access the device
* @port1: one-based index of port; ignored for root hubs
* Context: !in_interrupt()
*
* Only hub drivers (including virtual root hub drivers for host
* controllers) should ever call this.
*
* This call may not be used in a non-sleeping context.
*/
struct usb_device *
usb_alloc_dev(struct usb_device *parent, struct usb_bus *bus, unsigned port1)
{
struct usb_device *dev;
dev = kzalloc(sizeof(*dev), GFP_KERNEL);
if (!dev)
return NULL;
if (!usb_get_hcd(bus_to_hcd(bus))) {
kfree(dev);
return NULL;
}
device_initialize(&dev->dev);
dev->dev.bus = &usb_bus_type;
dev->dev.type = &usb_device_type;
dev->dev.dma_mask = bus->controller->dma_mask;
set_dev_node(&dev->dev, dev_to_node(bus->controller));
dev->state = USB_STATE_ATTACHED;
INIT_LIST_HEAD(&dev->ep0.urb_list);
dev->ep0.desc.bLength = USB_DT_ENDPOINT_SIZE;
dev->ep0.desc.bDescriptorType = USB_DT_ENDPOINT;
/* ep0 maxpacket comes later, from device descriptor */
dev->ep_in[0] = dev->ep_out[0] = &dev->ep0;
/* Save readable and stable topology id, distinguishing devices
* by location for diagnostics, tools, driver model, etc. The
* string is a path along hub ports, from the root. Each device's
* dev->devpath will be stable until USB is re-cabled, and hubs
* are often labeled with these port numbers. The bus_id isn't
* as stable: bus->busnum changes easily from modprobe order,
* cardbus or pci hotplugging, and so on.
*/
if (unlikely(!parent)) {
dev->devpath[0] = '0';
dev->dev.parent = bus->controller;
sprintf(&dev->dev.bus_id[0], "usb%d", bus->busnum);
} else {
/* match any labeling on the hubs; it's one-based */
if (parent->devpath[0] == '0')
snprintf(dev->devpath, sizeof dev->devpath,
"%d", port1);
else
snprintf(dev->devpath, sizeof dev->devpath,
"%s.%d", parent->devpath, port1);
dev->dev.parent = &parent->dev;
sprintf(&dev->dev.bus_id[0], "%d-%s",
bus->busnum, dev->devpath);
/* hub driver sets up TT records */
}
dev->portnum = port1;
dev->bus = bus;
dev->parent = parent;
INIT_LIST_HEAD(&dev->filelist);
#ifdef CONFIG_PM
mutex_init(&dev->pm_mutex);
INIT_DELAYED_WORK(&dev->autosuspend, usb_autosuspend_work);
dev->autosuspend_delay = usb_autosuspend_delay * HZ;
#endif
return dev;
}
/**
* usb_get_dev - increments the reference count of the usb device structure
* @dev: the device being referenced
*
* Each live reference to a device should be refcounted.
*
* Drivers for USB interfaces should normally record such references in
* their probe() methods, when they bind to an interface, and release
* them by calling usb_put_dev(), in their disconnect() methods.
*
* A pointer to the device with the incremented reference counter is returned.
*/
struct usb_device *usb_get_dev(struct usb_device *dev)
{
if (dev)
get_device(&dev->dev);
return dev;
}
/**
* usb_put_dev - release a use of the usb device structure
* @dev: device that's been disconnected
*
* Must be called when a user of a device is finished with it. When the last
* user of the device calls this function, the memory of the device is freed.
*/
void usb_put_dev(struct usb_device *dev)
{
if (dev)
put_device(&dev->dev);
}
/**
* usb_get_intf - increments the reference count of the usb interface structure
* @intf: the interface being referenced
*
* Each live reference to a interface must be refcounted.
*
* Drivers for USB interfaces should normally record such references in
* their probe() methods, when they bind to an interface, and release
* them by calling usb_put_intf(), in their disconnect() methods.
*
* A pointer to the interface with the incremented reference counter is
* returned.
*/
struct usb_interface *usb_get_intf(struct usb_interface *intf)
{
if (intf)
get_device(&intf->dev);
return intf;
}
/**
* usb_put_intf - release a use of the usb interface structure
* @intf: interface that's been decremented
*
* Must be called when a user of an interface is finished with it. When the
* last user of the interface calls this function, the memory of the interface
* is freed.
*/
void usb_put_intf(struct usb_interface *intf)
{
if (intf)
put_device(&intf->dev);
}
/* USB device locking
*
* USB devices and interfaces are locked using the semaphore in their
* embedded struct device. The hub driver guarantees that whenever a
* device is connected or disconnected, drivers are called with the
* USB device locked as well as their particular interface.
*
* Complications arise when several devices are to be locked at the same
* time. Only hub-aware drivers that are part of usbcore ever have to
* do this; nobody else needs to worry about it. The rule for locking
* is simple:
*
* When locking both a device and its parent, always lock the
* the parent first.
*/
/**
* usb_lock_device_for_reset - cautiously acquire the lock for a
* usb device structure
* @udev: device that's being locked
* @iface: interface bound to the driver making the request (optional)
*
* Attempts to acquire the device lock, but fails if the device is
* NOTATTACHED or SUSPENDED, or if iface is specified and the interface
* is neither BINDING nor BOUND. Rather than sleeping to wait for the
* lock, the routine polls repeatedly. This is to prevent deadlock with
* disconnect; in some drivers (such as usb-storage) the disconnect()
* or suspend() method will block waiting for a device reset to complete.
*
* Returns a negative error code for failure, otherwise 1 or 0 to indicate
* that the device will or will not have to be unlocked. (0 can be
* returned when an interface is given and is BINDING, because in that
* case the driver already owns the device lock.)
*/
int usb_lock_device_for_reset(struct usb_device *udev,
const struct usb_interface *iface)
{
unsigned long jiffies_expire = jiffies + HZ;
if (udev->state == USB_STATE_NOTATTACHED)
return -ENODEV;
if (udev->state == USB_STATE_SUSPENDED)
return -EHOSTUNREACH;
if (iface) {
switch (iface->condition) {
case USB_INTERFACE_BINDING:
return 0;
case USB_INTERFACE_BOUND:
break;
default:
return -EINTR;
}
}
while (usb_trylock_device(udev) != 0) {
/* If we can't acquire the lock after waiting one second,
* we're probably deadlocked */
if (time_after(jiffies, jiffies_expire))
return -EBUSY;
msleep(15);
if (udev->state == USB_STATE_NOTATTACHED)
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 thrashing IOMMU
* hardware during URB completion/resubmit. The implementation varies between
* platforms, depending on details of how DMA will work to this device.
* Using these buffers also eliminates cacheline sharing problems on
* architectures where CPU caches are not DMA-coherent. On systems without
* bus-snooping caches, these buffers are uncached.
*
* 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().
*/
#if 0
struct urb *usb_buffer_map(struct urb *urb)
{
struct usb_bus *bus;
struct device *controller;
if (!urb
|| !urb->dev
|| !(bus = urb->dev->bus)
|| !(controller = bus->controller))
return NULL;
if (controller->dma_mask) {
urb->transfer_dma = dma_map_single(controller,
urb->transfer_buffer, urb->transfer_buffer_length,
usb_pipein(urb->pipe)
? DMA_FROM_DEVICE : DMA_TO_DEVICE);
if (usb_pipecontrol(urb->pipe))
urb->setup_dma = dma_map_single(controller,
urb->setup_packet,
sizeof(struct usb_ctrlrequest),
DMA_TO_DEVICE);
// FIXME generic api broken like pci, can't report errors
// if (urb->transfer_dma == DMA_ADDR_INVALID) return 0;
} else
urb->transfer_dma = ~0;
urb->transfer_flags |= (URB_NO_TRANSFER_DMA_MAP
| URB_NO_SETUP_DMA_MAP);
return urb;
}
#endif /* 0 */
/* 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
*/
#if 0
/**
* usb_buffer_dmasync - synchronize DMA and CPU view of buffer(s)
* @urb: urb whose transfer_buffer/setup_packet will be synchronized
*/
void usb_buffer_dmasync(struct urb *urb)
{
struct usb_bus *bus;
struct device *controller;
if (!urb
|| !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)
|| !urb->dev
|| !(bus = urb->dev->bus)
|| !(controller = bus->controller))
return;
if (controller->dma_mask) {
dma_sync_single(controller,
urb->transfer_dma, urb->transfer_buffer_length,
usb_pipein(urb->pipe)
? DMA_FROM_DEVICE : DMA_TO_DEVICE);
if (usb_pipecontrol(urb->pipe))
dma_sync_single(controller,
urb->setup_dma,
sizeof(struct usb_ctrlrequest),
DMA_TO_DEVICE);
}
}
#endif
/**
* 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().
*/
#if 0
void usb_buffer_unmap(struct urb *urb)
{
struct usb_bus *bus;
struct device *controller;
if (!urb
|| !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)
|| !urb->dev
|| !(bus = urb->dev->bus)
|| !(controller = bus->controller))
return;
if (controller->dma_mask) {
dma_unmap_single(controller,
urb->transfer_dma, urb->transfer_buffer_length,
usb_pipein(urb->pipe)
? DMA_FROM_DEVICE : DMA_TO_DEVICE);
if (usb_pipecontrol(urb->pipe))
dma_unmap_single(controller,
urb->setup_dma,
sizeof(struct usb_ctrlrequest),
DMA_TO_DEVICE);
}
urb->transfer_flags &= ~(URB_NO_TRANSFER_DMA_MAP
| URB_NO_SETUP_DMA_MAP);
}
#endif /* 0 */
/**
* 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
*/
#if 0
/**
* usb_buffer_dmasync_sg - synchronize DMA and CPU view of scatterlist buffer(s)
* @dev: device to which the scatterlist will be mapped
* @pipe: endpoint defining the mapping direction
* @sg: the scatterlist to synchronize
* @n_hw_ents: the positive return value from usb_buffer_map_sg
*
* Use this when you are re-using a scatterlist's data buffers for
* another USB request.
*/
void usb_buffer_dmasync_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_sync_sg(controller, sg, n_hw_ents,
usb_pipein(pipe) ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
}
#endif
/**
* 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);
#if 0
EXPORT_SYMBOL(usb_buffer_map);
EXPORT_SYMBOL(usb_buffer_dmasync);
EXPORT_SYMBOL(usb_buffer_unmap);
#endif
EXPORT_SYMBOL(usb_buffer_map_sg);
#if 0
EXPORT_SYMBOL(usb_buffer_dmasync_sg);
#endif
EXPORT_SYMBOL(usb_buffer_unmap_sg);
MODULE_LICENSE("GPL");