Hi Daniel,
On Tue, Aug 12, 2014 at 11:58 AM, Daniel Mack <zonque@xxxxxxxxx> wrote:
> 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.
Sure.
>
>> };
>>
>> #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.
I will read the kernel style doc and fix this.
>
>> + 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.
mode is set to 1 when (urb->transfer_flags & URB_ZERO_PACKET), in
musb_tx_dma_program in musb_host.c.
Regards,
-Bin.
>
>
> Thanks,
> Daniel
>
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