Hi Bin,
On 08/12/2014 06:46 PM, Bin Liu wrote:
> drivers/usb/musb/musb_cppi41.c | 15 +++++++++++++--
> 1 file changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/musb/musb_cppi41.c b/drivers/usb/musb/musb_cppi41.c
> index 5989def..e9a0e54 100644
> --- a/drivers/usb/musb/musb_cppi41.c
> +++ b/drivers/usb/musb/musb_cppi41.c
> @@ -39,6 +39,7 @@ struct cppi41_dma_channel {
> u32 transferred;
> u32 packet_sz;
> struct list_head tx_check;
> + u32 tx_zlp;
'bool' might be easier to read later.
> };
>
> #define MUSB_DMA_NUM_CHANNELS 15
> @@ -122,6 +123,8 @@ static void cppi41_trans_done(struct cppi41_dma_channel
> *cppi41_channel)
> {
> struct musb_hw_ep *hw_ep = cppi41_channel->hw_ep;
> struct musb *musb = hw_ep->musb;
> + void __iomem *epio = hw_ep->regs;
> + u16 csr;
>
> if (!cppi41_channel->prog_len) {
>
> @@ -130,15 +133,22 @@ static void cppi41_trans_done(struct cppi41_dma_channel
> *cppi41_channel)
> cppi41_channel->transferred;
> cppi41_channel->channel.status = MUSB_DMA_STATUS_FREE;
> cppi41_channel->channel.rx_packet_done = true;
> +
> + /* transmit ZLP using PIO mode for transfers which size is
> + * multiple of EP packet size. */
I'd prefer this block to follow the kernel-style of comments, even
though this driver is full of other flavors.
> + if (cppi41_channel->tx_zlp && (cppi41_channel->transferred %
> + cppi41_channel->packet_sz) == 0) {
> + musb_ep_select(musb->mregs, hw_ep->epnum);
> + csr = MUSB_TXCSR_MODE | MUSB_TXCSR_TXPKTRDY;
> + musb_writew(epio, MUSB_TXCSR, csr);
> + }
> musb_dma_completion(musb, hw_ep->epnum, cppi41_channel->is_tx);
> } else {
> /* next iteration, reload */
> struct dma_chan *dc = cppi41_channel->dc;
> struct dma_async_tx_descriptor *dma_desc;
> enum dma_transfer_direction direction;
> - u16 csr;
> u32 remain_bytes;
> - void __iomem *epio = cppi41_channel->hw_ep->regs;
>
> cppi41_channel->buf_addr += cppi41_channel->packet_sz;
>
> @@ -362,6 +372,7 @@ static bool cppi41_configure_channel(struct dma_channel
> *channel,
> cppi41_channel->total_len = len;
> cppi41_channel->transferred = 0;
> cppi41_channel->packet_sz = packet_sz;
> + cppi41_channel->tx_zlp = (cppi41_channel->is_tx && mode) ? 1 : 0;
Don't you need to check for (urb->transfer_flags & URB_ZERO_PACKET)
somewhere here? I'd not expect an extra 0-byte packet at the end of a
transfer unless this flag is set.
Thanks,
Daniel
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