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usb: gadget: function: f_fs: Let ffs_epfile_ioctl wait for enable.

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This allows users to make an ioctl call as the first action on a
connection. Ex, some functions might want to get endpoint size
before making any i/os.

Previously, calling ioctls before read/write would depending on the
timing of endpoints being enabled.

ESHUTDOWN is now a possible return value and ENODEV is not, so change
docs accordingly.

Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Jerry Zhang <zhangjerry@google.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
This commit is contained in:
Jerry Zhang
2017-04-19 18:23:38 -07:00
committed by Felipe Balbi
parent 8a8b161df5
commit 222155de45
2 changed files with 58 additions and 42 deletions
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23
drivers/usb/gadget/function/f_fs.c
View File

@@ -1189,6 +1189,7 @@ static long ffs_epfile_ioctl(struct file *file, unsigned code,
unsigned long value)
{
struct ffs_epfile *epfile = file->private_data;
struct ffs_ep *ep;
int ret;
ENTER();
@@ -1196,8 +1197,25 @@ static long ffs_epfile_ioctl(struct file *file, unsigned code,
if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
return -ENODEV;
/* Wait for endpoint to be enabled */
ep = epfile->ep;
if (!ep) {
if (file->f_flags & O_NONBLOCK)
return -EAGAIN;
ret = wait_event_interruptible(epfile->wait, (ep = epfile->ep));
if (ret)
return -EINTR;
}
spin_lock_irq(&epfile->ffs->eps_lock);
if (likely(epfile->ep)) {
/* In the meantime, endpoint got disabled or changed. */
if (epfile->ep != ep) {
spin_unlock_irq(&epfile->ffs->eps_lock);
return -ESHUTDOWN;
}
switch (code) {
case FUNCTIONFS_FIFO_STATUS:
ret = usb_ep_fifo_status(epfile->ep->ep);
@@ -1238,9 +1256,6 @@ static long ffs_epfile_ioctl(struct file *file, unsigned code,
default:
ret = -ENOTTY;
}
} else {
ret = -ENODEV;
}
spin_unlock_irq(&epfile->ffs->eps_lock);
return ret;

7
include/uapi/linux/usb/functionfs.h
View File

@@ -275,13 +275,14 @@ struct usb_functionfs_event {
#define FUNCTIONFS_INTERFACE_REVMAP _IO('g', 128)
/*
* Returns real bEndpointAddress of an endpoint. If function is not
* active returns -ENODEV.
* Returns real bEndpointAddress of an endpoint. If endpoint shuts down
* during the call, returns -ESHUTDOWN.
*/
#define FUNCTIONFS_ENDPOINT_REVMAP _IO('g', 129)
/*
* Returns endpoint descriptor. If function is not active returns -ENODEV.
* Returns endpoint descriptor. If endpoint shuts down during the call,
* returns -ESHUTDOWN.
*/
#define FUNCTIONFS_ENDPOINT_DESC _IOR('g', 130, \
struct usb_endpoint_descriptor)