Re: [PATCH v2 2/2] bcm2835_dma: Re-initialize xlen in TD mode

[Philippe Mathieu-Daudé]

On 2/3/20 4:40 PM, Rene Stange wrote:
TD (two dimensions) DMA mode did not work, because the xlen variable
has not been re-initialized before each additional ylen run through
in bcm2835_dma_update(), which has been fixed.

"which has been fixed" confused me, because this current patch is fixing 
it. Using present tense makes it easier to understand for non-native 
English speakers IMHO:

  TD (two dimensions) DMA mode does not work, because the xlen
  variable is not re-initialized before each additional ylen
  run through in bcm2835_dma_update(). Fix it.

If you agree, maybe Peter (the maintainer who will take your patch) can 
make the change for you.

Reviewed-by: Philippe Mathieu-Daudé <phi...@redhat.com>


Signed-off-by: Rene Stange <rs...@o2online.de>
---
  hw/dma/bcm2835_dma.c | 4 +++-
  1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/hw/dma/bcm2835_dma.c b/hw/dma/bcm2835_dma.c
index 667d951a6f..ccff5ed55b 100644
--- a/hw/dma/bcm2835_dma.c
+++ b/hw/dma/bcm2835_dma.c
@@ -54,7 +54,7 @@
  static void bcm2835_dma_update(BCM2835DMAState *s, unsigned c)
  {
      BCM2835DMAChan *ch = &s->chan[c];
-    uint32_t data, xlen, ylen;
+    uint32_t data, xlen, xlen_td, ylen;
      int16_t dst_stride, src_stride;
  
      if (!(s->enable & (1 << c))) {
@@ -82,6 +82,7 @@ static void bcm2835_dma_update(BCM2835DMAState *s, unsigned c)
              dst_stride = 0;
              src_stride = 0;
          }
+        xlen_td = xlen;
  
          while (ylen != 0) {
              /* Normal transfer mode */
@@ -117,6 +118,7 @@ static void bcm2835_dma_update(BCM2835DMAState *s, unsigned 
c)
              if (--ylen != 0) {
                  ch->source_ad += src_stride;
                  ch->dest_ad += dst_stride;
+                xlen = xlen_td;
              }
          }
          ch->cs |= BCM2708_DMA_END;