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Commit 9267edaf authored by Bin Liu's avatar Bin Liu Committed by Felipe Balbi
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usb: musb: cppi41: fix not transmitting zero length packet issue 



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: default avatarBin Liu <b-liu@ti.com>
Signed-off-by: default avatarFelipe Balbi <balbi@ti.com>
parent 69e273c0

drivers/usb/musb/musb_cppi41.c

+15 −2
Original line number Diff line number Diff line
@@ -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