Hi,
Macpaul Lin <macpaul.lin@xxxxxxxxxxxx> writes:
> Some USB hardware like DMA engine can help to process (split) the data
> of each URB request into small packets. For example, the max packet size
> of high speed is 512 bytes. These kinds of hardware can help to split
> the continue Tx/Rx data requests into packets just at the max packet
> size during transmission. Hence upper layer software can reduce some
> effort for queueing many requests back and forth for larger data.
>
> Here we introduce "can_exceed_maxp" flag in gadget when these kinds of
> hardware is ready to support these operations.
>
> Signed-off-by: Macpaul Lin <macpaul.lin@xxxxxxxxxxxx>
> ---
> drivers/usb/mtu3/mtu3_qmu.c | 11 ++++++++++-
> include/linux/usb/gadget.h | 1 +
> 2 files changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/mtu3/mtu3_qmu.c b/drivers/usb/mtu3/mtu3_qmu.c
> index 3f414f9..2b51a20 100644
> --- a/drivers/usb/mtu3/mtu3_qmu.c
> +++ b/drivers/usb/mtu3/mtu3_qmu.c
> @@ -620,7 +620,7 @@ irqreturn_t mtu3_qmu_isr(struct mtu3 *mtu)
>
> int mtu3_qmu_init(struct mtu3 *mtu)
> {
> -
> + int i;
> compiletime_assert(QMU_GPD_SIZE == 16, "QMU_GPD size SHOULD be 16B");
>
> mtu->qmu_gpd_pool = dma_pool_create("QMU_GPD", mtu->dev,
> @@ -629,10 +629,19 @@ int mtu3_qmu_init(struct mtu3 *mtu)
> if (!mtu->qmu_gpd_pool)
> return -ENOMEM;
>
> + /* Let gadget know we can process request larger than max packet */
> + for (i = 1; i < mtu->num_eps; i++)
> + mtu->ep_array[i].ep.can_exceed_maxp = 1;
> +
> return 0;
> }
>
> void mtu3_qmu_exit(struct mtu3 *mtu)
> {
> + int i;
> dma_pool_destroy(mtu->qmu_gpd_pool);
> +
> + /* Disable large request support */
> + for (i = 1; i < mtu->num_eps; i++)
> + mtu->ep_array[i].ep.can_exceed_maxp = 0;
> }
> diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
> index 6a17817..60e0645 100644
> --- a/include/linux/usb/gadget.h
> +++ b/include/linux/usb/gadget.h
> @@ -236,6 +236,7 @@ struct usb_ep {
> unsigned max_streams:16;
> unsigned mult:2;
> unsigned maxburst:5;
> + unsigned can_exceed_maxp:1;
every driver does this without this flag. This is unnecessary.
--
balbi
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