media: coda: disable BWB only while decoding on CODA 960

Disabling the BWB works around hangups observed while decoding. Since no
issues have been observed while encoding, and disabling BWB also reduces
encoding performance, reenable it for encoding.

Fixes: 89ed025d ("[media] coda: disable BWB for all codecs on CODA 960")
Reported-by: Ian Arkver <ian.arkver.dev@gmail.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Tested-by: Ian Arkver <ian.arkver.dev@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/platform/coda/coda-common.c

@@ -73,7 +73,7 @@ MODULE_PARM_DESC(disable_vdoa, "Disable Video Data Order Adapter tiled to raster
 
 static int enable_bwb = 0;
 module_param(enable_bwb, int, 0644);
-MODULE_PARM_DESC(enable_bwb, "Enable BWB unit, may crash on certain streams");
+MODULE_PARM_DESC(enable_bwb, "Enable BWB unit for decoding, may crash on certain streams");
 
 void coda_write(struct coda_dev *dev, u32 data, u32 reg)
 {
@@ -1988,7 +1988,13 @@ static int coda_open(struct file *file)
 	ctx->idx = idx;
 	switch (dev->devtype->product) {
 	case CODA_960:
-		if (enable_bwb)
+		/*
+		 * Enabling the BWB when decoding can hang the firmware with
+		 * certain streams. The issue was tracked as ENGR00293425 by
+		 * Freescale. As a workaround, disable BWB for all decoders.
+		 * The enable_bwb module parameter allows to override this.
+		 */
+		if (enable_bwb || ctx->inst_type == CODA_INST_ENCODER)
 			ctx->frame_mem_ctrl = CODA9_FRAME_ENABLE_BWB;
 		/* fallthrough */
 	case CODA_7541:
@@ -2192,7 +2198,8 @@ static int coda_hw_init(struct coda_dev *dev)
 			   CODA_REG_BIT_STREAM_CTRL);
 	}
 	if (dev->devtype->product == CODA_960)
-		coda_write(dev, 1 << 12, CODA_REG_BIT_FRAME_MEM_CTRL);
+		coda_write(dev, CODA9_FRAME_ENABLE_BWB,
+				CODA_REG_BIT_FRAME_MEM_CTRL);
 	else
 		coda_write(dev, 0, CODA_REG_BIT_FRAME_MEM_CTRL);