usb: musb: disable double buffering when it's broken

We know that blackfin doesn't support double
buffering feature as of today. So we add a
flag set by musb_platform_init() to forcefully
disable that feature.

Such flag is created and marked as deprecated
to force us to find a solution for the missing
double buffering support on blackfin.

Signed-off-by: Felipe Balbi <balbi@ti.com>

4 files changed, 28 insertions, 8 deletions

diff --git a/drivers/usb/musb/blackfin.c b/drivers/usb/musb/blackfin.c
index eeba228eb2af..9d49d1cd7ce2 100644
--- a/drivers/usb/musb/blackfin.c
+++ b/drivers/usb/musb/blackfin.c
@@ -404,6 +404,7 @@ static int bfin_musb_init(struct musb *musb)
                 musb->xceiv->set_power = bfin_musb_set_power;
 
         musb->isr = blackfin_interrupt;
+        musb->double_buffer_not_ok = true;
 
         return 0;
 }
diff --git a/drivers/usb/musb/musb_core.h b/drivers/usb/musb/musb_core.h
index d0c236f8e191..d74a8113ae74 100644
--- a/drivers/usb/musb/musb_core.h
+++ b/drivers/usb/musb/musb_core.h
@@ -488,6 +488,18 @@ struct musb {
         unsigned                set_address:1;
         unsigned                test_mode:1;
         unsigned                softconnect:1;
+        /*
+         * FIXME: Remove this flag.
+         *
+         * This is only added to allow Blackfin to work
+         * with current driver. For some unknown reason
+         * Blackfin doesn't work with double buffering
+         * and that's enabled by default.
+         *
+         * We added this flag to forcefully disable double
+         * buffering until we get it working.
+         */
+        unsigned                double_buffer_not_ok:1 __deprecated;
 
         u8                      address;
         u8                      test_mode_nr;
diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c
index ed58c6c8f15c..23dad4c8785d 100644
--- a/drivers/usb/musb/musb_gadget.c
+++ b/drivers/usb/musb/musb_gadget.c
@@ -989,7 +989,11 @@ static int musb_gadget_enable(struct usb_ep *ep,
                 /* Set TXMAXP with the FIFO size of the endpoint
                  * to disable double buffering mode.
                  */
-                musb_writew(regs, MUSB_TXMAXP, musb_ep->packet_sz | (musb_ep->hb_mult << 11));
+                if (musb->double_buffer_not_ok)
+                        musb_writew(regs, MUSB_TXMAXP, hw_ep->max_packet_sz_tx);
+                else
+                        musb_writew(regs, MUSB_TXMAXP, musb_ep->packet_sz
+                                        | (musb_ep->hb_mult << 11));
 
                 csr = MUSB_TXCSR_MODE | MUSB_TXCSR_CLRDATATOG;
                 if (musb_readw(regs, MUSB_TXCSR)
@@ -1025,7 +1029,11 @@ static int musb_gadget_enable(struct usb_ep *ep,
                 /* Set RXMAXP with the FIFO size of the endpoint
                  * to disable double buffering mode.
                  */
-                musb_writew(regs, MUSB_RXMAXP, musb_ep->packet_sz | (musb_ep->hb_mult << 11));
+                if (musb->double_buffer_not_ok)
+                        musb_writew(regs, MUSB_RXMAXP, hw_ep->max_packet_sz_tx);
+                else
+                        musb_writew(regs, MUSB_RXMAXP, musb_ep->packet_sz
+                                        | (musb_ep->hb_mult << 11));
 
                 /* force shared fifo to OUT-only mode */
                 if (hw_ep->is_shared_fifo) {
diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c
index 4d5bcb4e14d2..0f523d7db57b 100644
--- a/drivers/usb/musb/musb_host.c
+++ b/drivers/usb/musb/musb_host.c
@@ -609,7 +609,7 @@ musb_rx_reinit(struct musb *musb, struct musb_qh *qh, struct musb_hw_ep *ep)
         /* Set RXMAXP with the FIFO size of the endpoint
          * to disable double buffer mode.
          */
-        if (musb->hwvers < MUSB_HWVERS_2000)
+        if (musb->double_buffer_not_ok)
                 musb_writew(ep->regs, MUSB_RXMAXP, ep->max_packet_sz_rx);
         else
                 musb_writew(ep->regs, MUSB_RXMAXP,
@@ -784,14 +784,13 @@ static void musb_ep_program(struct musb *musb, u8 epnum,
                 /* protocol/endpoint/interval/NAKlimit */
                 if (epnum) {
                         musb_writeb(epio, MUSB_TXTYPE, qh->type_reg);
-                        if (can_bulk_split(musb, qh->type))
+                        if (musb->double_buffer_not_ok)
                                 musb_writew(epio, MUSB_TXMAXP,
-                                        packet_sz
-                                        | ((hw_ep->max_packet_sz_tx /
-                                                packet_sz) - 1) << 11);
+                                                hw_ep->max_packet_sz_tx);
                         else
                                 musb_writew(epio, MUSB_TXMAXP,
-                                        packet_sz);
+                                                qh->maxpacket |
+                                                ((qh->hb_mult - 1) << 11));
                         musb_writeb(epio, MUSB_TXINTERVAL, qh->intv_reg);
                 } else {
                         musb_writeb(epio, MUSB_NAKLIMIT0, qh->intv_reg);