dmaengine: at_xdmac: fix bug about channel configuration

When using descriptor view 2 or higher, we don't write the configuration
into AT_XDMAC_CC register because this configuration will be fetch from
the descriptor. Unfortunately, the PROT bit is not updated with this
method, we have to do it manually before enabling the channel.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c
index cf1213de7865ecb95e20c9d273a57ec1981203a7..52ca1ccefa3f317a181dcb0d10043f5f198cf293 100644 (file)
--- a/drivers/dma/at_xdmac.c
+++ b/drivers/dma/at_xdmac.c
@@ -359,18 +359,19 @@ static void at_xdmac_start_xfer(struct at_xdmac_chan *atchan,
         * descriptor view 2 since some fields of the configuration register
         * depend on transfer size and src/dest addresses.
         */
-       if (at_xdmac_chan_is_cyclic(atchan)) {
+       if (at_xdmac_chan_is_cyclic(atchan))
                reg = AT_XDMAC_CNDC_NDVIEW_NDV1;
-               at_xdmac_chan_write(atchan, AT_XDMAC_CC, first->lld.mbr_cfg);
-       } else if (first->lld.mbr_ubc & AT_XDMAC_MBR_UBC_NDV3) {
+       else if (first->lld.mbr_ubc & AT_XDMAC_MBR_UBC_NDV3)
                reg = AT_XDMAC_CNDC_NDVIEW_NDV3;
-       } else {
-               /*
-                * No need to write AT_XDMAC_CC reg, it will be done when the
-                * descriptor is fecthed.
-                */
+       else
                reg = AT_XDMAC_CNDC_NDVIEW_NDV2;
-       }
+       /*
+        * Even if the register will be updated from the configuration in the
+        * descriptor when using view 2 or higher, the PROT bit won't be set
+        * properly. This bit can be modified only by using the channel
+        * configuration register.
+        */
+       at_xdmac_chan_write(atchan, AT_XDMAC_CC, first->lld.mbr_cfg);
 
        reg |= AT_XDMAC_CNDC_NDDUP
               | AT_XDMAC_CNDC_NDSUP