[PATCH v2 3/4] usb: musb: gadget: don't program dma for zero byte tx

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This is to reduce the overhead of dma programming for zero byte
transmit as same can be done using pio mode.

Signed-off-by: Ajay Kumar Gupta <ajay.gupta@xxxxxx>
---
 drivers/usb/musb/musb_gadget.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c
index b330ea6..841b442 100644
--- a/drivers/usb/musb/musb_gadget.c
+++ b/drivers/usb/musb/musb_gadget.c
@@ -366,7 +366,7 @@ static void txstate(struct musb *musb, struct musb_request *req)
 		request_size = min_t(size_t, request->length - request->actual,
 					musb_ep->dma->max_len);
 
-		use_dma = (request->dma != DMA_ADDR_INVALID);
+		use_dma = (request->dma != DMA_ADDR_INVALID && request_size);
 
 		/* MUSB_TXCSR_P_ISO is still set correctly */
 
-- 
1.7.0.4

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