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path: root/drivers/usb/musb/musb_cppi41.c
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Diffstat (limited to 'drivers/usb/musb/musb_cppi41.c')
-rw-r--r--drivers/usb/musb/musb_cppi41.c17
1 files changed, 15 insertions, 2 deletions
diff --git a/drivers/usb/musb/musb_cppi41.c b/drivers/usb/musb/musb_cppi41.c
index 47ae6455d073..3ee133f675ab 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;
+ 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