On Mon, Nov 11 2013, David Cohen wrote:
> Due to USB controllers may have different restrictions, usb gadget layer
> needs to provide a generic way to inform gadget functions to complain
> with non-standard requirements.
>
> This patch adds 'quirk_ep_out_aligned_size' field to struct usb_gadget
> to inform when controller's epout requires buffer size to be aligned to
> MaxPacketSize. A helper is also provided to align buffer size when
> necessary.
>
> Signed-off-by: David Cohen <david.a.cohen@xxxxxxxxxxxxxxx>
> Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Acked-by: Michal Nazarewicz <mina86@xxxxxxxxxx>
> ---
>
> Michal,
>
> I added prefix 'usb: f_fs: ' to patch's subject. I did not add 'usb: gadget:
> f_fs' due to it would be too long.
>
>
> include/linux/usb/gadget.h | 16 ++++++++++++++++
> 1 file changed, 16 insertions(+)
>
> diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
> index 23b3bfd0a842..41e8834af57d 100644
> --- a/include/linux/usb/gadget.h
> +++ b/include/linux/usb/gadget.h
> @@ -441,6 +441,19 @@ static inline void usb_ep_fifo_flush(struct usb_ep *ep)
> ep->ops->fifo_flush(ep);
> }
>
> +/**
> + * usb_ep_align_maxpacketsize - returns @len aligned to ep's maxpacketsize
> + * @ep: the endpoint whose maxpacketsize is used to align @len
> + * @len: buffer size's length to align to @ep's maxpacketsize
> + *
> + * This helper is used in case it's required for any reason to align buffer's
> + * size to an ep's maxpacketsize.
> + */
> +static inline size_t usb_ep_align_maxpacketsize(struct usb_ep *ep, size_t len)
> +{
> + return round_up(len, (size_t)ep->desc->wMaxPacketSize);
> +}
> +
Come to think of it, perhaps even better helper would be:
static inline size_t usb_ep_align_maybe(
struct usb_gadget *gadget, struct usb_ep *ep, size_t len) {
return gadget->quir_ep_out_aligned_size ?
round_up(len, (size_t)ep->desc->wMaxPacketSize) : len;
}
>
> /*-------------------------------------------------------------------------*/
>
> @@ -502,6 +515,8 @@ struct usb_gadget_ops {
> * only supports HNP on a different root port.
> * @b_hnp_enable: OTG device feature flag, indicating that the A-Host
> * enabled HNP support.
> + * @quirk_ep_out_aligned_size: epout requires buffer size to be aligned to
> + * MaxPacketSize.
> *
> * Gadgets have a mostly-portable "gadget driver" implementing device
> * functions, handling all usb configurations and interfaces. Gadget
> @@ -541,6 +556,7 @@ struct usb_gadget {
> unsigned b_hnp_enable:1;
> unsigned a_hnp_support:1;
> unsigned a_alt_hnp_support:1;
> + unsigned quirk_ep_out_aligned_size:1;
> };
> #define work_to_gadget(w) (container_of((w), struct usb_gadget, work))
>
> --
> 1.8.4.rc3
>
--
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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