USB: musb: disable double buffering for older RTL versions
Trying to use double buffer modes in RTL versions <2.0 may result in
infinite hangs or data corruption. So avoid them with older versions.
Signed-off-by: Cliff Cai <cliff.cai@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c
index cbcf14a2..41de3a9 100644
--- a/drivers/usb/musb/musb_gadget.c
+++ b/drivers/usb/musb/musb_gadget.c
@@ -895,7 +895,14 @@
/* REVISIT if can_bulk_split(), use by updating "tmp";
* likewise high bandwidth periodic tx
*/
- musb_writew(regs, MUSB_TXMAXP, tmp);
+ /* Set TXMAXP with the FIFO size of the endpoint
+ * to disable double buffering mode. Currently, It seems that double
+ * buffering has problem if musb RTL revision number < 2.0.
+ */
+ if (musb->hwvers < MUSB_HWVERS_2000)
+ musb_writew(regs, MUSB_TXMAXP, hw_ep->max_packet_sz_tx);
+ else
+ musb_writew(regs, MUSB_TXMAXP, tmp);
csr = MUSB_TXCSR_MODE | MUSB_TXCSR_CLRDATATOG;
if (musb_readw(regs, MUSB_TXCSR)
@@ -925,7 +932,13 @@
/* REVISIT if can_bulk_combine() use by updating "tmp"
* likewise high bandwidth periodic rx
*/
- musb_writew(regs, MUSB_RXMAXP, tmp);
+ /* Set RXMAXP with the FIFO size of the endpoint
+ * to disable double buffering mode.
+ */
+ if (musb->hwvers < MUSB_HWVERS_2000)
+ musb_writew(regs, MUSB_RXMAXP, hw_ep->max_packet_sz_rx);
+ else
+ musb_writew(regs, MUSB_RXMAXP, tmp);
/* force shared fifo to OUT-only mode */
if (hw_ep->is_shared_fifo) {
