On Fri, Jan 17 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 | 42 ++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 42 insertions(+)
>
> diff --git a/drivers/usb/gadget/f_fs.c b/drivers/usb/gadget/f_fs.c
> @@ -558,6 +560,45 @@ 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:
> + mask |= (POLLIN | POLLOUT);
> + break;
> +
> + case FFS_SETUP_CANCELED:
The FFS_SETUP_CANCELED and FFS_SETUP_PENDING are the same case. ep0
never recovers from FFS_SETUP_CANCELED on its own, it waits for user
space to attempt to read or write something. So unless I'm missing
something the two cases should be merged together and in both POLLIN and
POLLOUT needs to be set.
> + break;
> + }
> + case FFS_CLOSING:
> + break;
> + }
> +
> + 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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