usb: musb: gadget: don't program dma for zero byte tx
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@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c
index 49d7bee..8d2cce1 100644
--- a/drivers/usb/musb/musb_gadget.c
+++ b/drivers/usb/musb/musb_gadget.c
@@ -373,7 +373,7 @@
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 */