1 files changed, 43 insertions, 26 deletions

diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c
index 44b331a74d5..82434dde6e9 100644
--- a/drivers/usb/musb/musb_gadget.c
+++ b/drivers/usb/musb/musb_gadget.c
@@ -634,6 +634,7 @@ static void rxstate(struct musb *musb, struct musb_request *req)
         u16                     len;
         u16                     csr = musb_readw(epio, MUSB_RXCSR);
         struct musb_hw_ep       *hw_ep = &musb->endpoints[epnum];
+        u8                      use_mode_1;
 
         if (hw_ep->is_shared_fifo)
                 musb_ep = &hw_ep->ep_in;
@@ -683,6 +684,18 @@ static void rxstate(struct musb *musb, struct musb_request *req)
 
         if (csr & MUSB_RXCSR_RXPKTRDY) {
                 len = musb_readw(epio, MUSB_RXCOUNT);
+
+                /*
+                 * Enable Mode 1 on RX transfers only when short_not_ok flag
+                 * is set. Currently short_not_ok flag is set only from
+                 * file_storage and f_mass_storage drivers
+                 */
+
+                if (request->short_not_ok && len == musb_ep->packet_sz)
+                        use_mode_1 = 1;
+                else
+                        use_mode_1 = 0;
+
                 if (request->actual < request->length) {
 #ifdef CONFIG_USB_INVENTRA_DMA
                         if (is_buffer_mapped(req)) {
@@ -714,37 +727,41 @@ static void rxstate(struct musb *musb, struct musb_request *req)
          * then becomes usable as a runtime "use mode 1" hint...
          */
 
-                                csr |= MUSB_RXCSR_DMAENAB;
-#ifdef USE_MODE1
-                                csr |= MUSB_RXCSR_AUTOCLEAR;
-                                /* csr |= MUSB_RXCSR_DMAMODE; */
-
-                                /* this special sequence (enabling and then
-                                 * disabling MUSB_RXCSR_DMAMODE) is required
-                                 * to get DMAReq to activate
-                                 */
-                                musb_writew(epio, MUSB_RXCSR,
-                                        csr | MUSB_RXCSR_DMAMODE);
-#else
-                                if (!musb_ep->hb_mult &&
-                                        musb_ep->hw_ep->rx_double_buffered)
+                                /* Experimental: Mode1 works with mass storage use cases */
+                                if (use_mode_1) {
                                         csr |= MUSB_RXCSR_AUTOCLEAR;
-#endif
-                                musb_writew(epio, MUSB_RXCSR, csr);
+                                        musb_writew(epio, MUSB_RXCSR, csr);
+                                        csr |= MUSB_RXCSR_DMAENAB;
+                                        musb_writew(epio, MUSB_RXCSR, csr);
+
+                                        /*
+                                         * this special sequence (enabling and then
+                                         * disabling MUSB_RXCSR_DMAMODE) is required
+                                         * to get DMAReq to activate
+                                         */
+                                        musb_writew(epio, MUSB_RXCSR,
+                                                csr | MUSB_RXCSR_DMAMODE);
+                                        musb_writew(epio, MUSB_RXCSR, csr);
+
+                                } else {
+                                        if (!musb_ep->hb_mult &&
+                                                musb_ep->hw_ep->rx_double_buffered)
+                                                csr |= MUSB_RXCSR_AUTOCLEAR;
+                                        csr |= MUSB_RXCSR_DMAENAB;
+                                        musb_writew(epio, MUSB_RXCSR, csr);
+                                }
 
                                 if (request->actual < request->length) {
                                         int transfer_size = 0;
-#ifdef USE_MODE1
-                                        transfer_size = min(request->length - request->actual,
-                                                        channel->max_len);
-#else
-                                        transfer_size = min(request->length - request->actual,
-                                                        (unsigned)len);
-#endif
-                                        if (transfer_size <= musb_ep->packet_sz)
-                                                musb_ep->dma->desired_mode = 0;
-                                        else
+                                        if (use_mode_1) {
+                                                transfer_size = min(request->length - request->actual,
+                                                                channel->max_len);
                                                 musb_ep->dma->desired_mode = 1;
+                                        } else {
+                                                transfer_size = min(request->length - request->actual,
+                                                                (unsigned)len);
+                                                musb_ep->dma->desired_mode = 0;
+                                        }
 
                                         use_dma = c->channel_program(
                                                         channel,