On Tue, Jan 14 2014, Robert Baldyga wrote:
> This patch adds poll function for file representing ep0.
>
> Ability of read from or write to ep0 file is related with actual state of ffs:
> - When desctiptors or strings are not written yet, POLLOUT flag is set.
> - If there is any event to read, POLLIN flag is set.
> - If setup request was read, POLLIN and POLLOUT flag is set, to allow
> send response (by performing I/O operation consistent with setup request
> direction) or set stall (by performing I/O operation opposite setup
> request direction).
>
> Signed-off-by: Robert Baldyga <r.baldyga@xxxxxxxxxxx>
> ---
> drivers/usb/gadget/f_fs.c | 43 +++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 41 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/gadget/f_fs.c b/drivers/usb/gadget/f_fs.c
> @@ -726,6 +725,45 @@ static long ffs_ep0_ioctl(struct file *file, unsigned code, unsigned long value)
> return ret;
> }
>
> +static unsigned int ffs_ep0_poll(struct file *file, poll_table *wait)
> +{
> + struct ffs_data *ffs = file->private_data;
> + unsigned int mask = POLLWRNORM;
> + int ret;
> +
> + ret = ffs_mutex_lock(&ffs->mutex, file->f_flags & O_NONBLOCK);
> + if (unlikely(ret < 0))
> + return mask;
> +
> + switch (ffs->state) {
> + case FFS_READ_DESCRIPTORS:
> + case FFS_READ_STRINGS:
> + mask |= POLLOUT;
> + break;
> +
> + case FFS_ACTIVE:
> + switch (FFS_SETUP_STATE(ffs)) {
> + case FFS_NO_SETUP:
> + if(ffs->ev.count)
> + mask |= POLLIN;
> + break;
> +
> + case FFS_SETUP_PENDING:
This should also be the case for:
case FFS_SETUP_CANCELED:
After all, we are waiting for user space to write/read something to the
end point so that we can return -EIDRM.
> + mask |= (POLLIN | POLLOUT);
> + break;
> +
> + default:
> + break;
This default is then unnecessary.
> + }
> + default:
> + break;
Having an explicit:
case FFS_CLOSING:
might assist the compiler in producing warnings later on if someone
decided to add some more values to ffs_state enum.
> + }
> +
> + mutex_unlock(&ffs->mutex);
> +
> + return mask;
> +}
> +
> static const struct file_operations ffs_ep0_operations = {
> .llseek = no_llseek,
>
--
Best regards, _ _
.o. | Liege of Serenely Enlightened Majesty of o' \,=./ `o
..o | Computer Science, Michał “mina86” Nazarewicz (o o)
ooo +--<mpn@xxxxxxxxxx>--<xmpp:mina86@xxxxxxxxxx>--ooO--(_)--Ooo--
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