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usb: musb: cppi41: fix not transmitting zero length packet issue

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CPPI TX does not transmit ZLP for TX transfers which
- transfer size is multiple of EP packet size,
- and URB_ZERO_PACKET is set in urb->transfer_flags.

The fix is transmitting the ZLP using PIO mode after the CPPI TX is
done.

Validated using the following usbtest write case in MUSB host mode.

  # testusb -t1 -c1

Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
This commit is contained in:
Bin Liu 2014-08-12 14:18:43 -05:00 committed by Felipe Balbi
parent 69e273c0b0
commit 9267edaf8c
1 changed files with 15 additions and 2 deletions
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17
drivers/usb/musb/musb_cppi41.c
View File

@ -39,6 +39,7 @@ struct cppi41_dma_channel {
u32 transferred;
u32 packet_sz;
struct list_head tx_check;
int tx_zlp;
};
#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 ||
(cppi41_channel->channel.status == MUSB_DMA_STATUS_FREE)) {
@ -131,15 +134,24 @@ 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.
*/
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;
@ -363,6 +375,7 @@ 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;
/*
* Due to AM335x' Advisory 1.0.13 we are not allowed to transfer more