Merge tag 'v2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6

[mv-sheeva.git] / drivers / media / video / ivtv / ivtv-irq.c

diff --git a/drivers/media/video/ivtv/ivtv-irq.c b/drivers/media/video/ivtv/ivtv-irq.c
index 9b4faf009196afad6de8f4b3ffeebc0dbd2f05e6..9c29e964d400b955d36074487c17c22e1195bbcd 100644 (file)
--- a/drivers/media/video/ivtv/ivtv-irq.c
+++ b/drivers/media/video/ivtv/ivtv-irq.c
@@ -628,22 +628,66 @@ static void ivtv_irq_enc_pio_complete(struct ivtv *itv)
 static void ivtv_irq_dma_err(struct ivtv *itv)
 {
        u32 data[CX2341X_MBOX_MAX_DATA];
+       u32 status;
 
        del_timer(&itv->dma_timer);
+
        ivtv_api_get_data(&itv->enc_mbox, IVTV_MBOX_DMA_END, 2, data);
+       status = read_reg(IVTV_REG_DMASTATUS);
        IVTV_DEBUG_WARN("DMA ERROR %08x %08x %08x %d\n", data[0], data[1],
-                               read_reg(IVTV_REG_DMASTATUS), itv->cur_dma_stream);
-       write_reg(read_reg(IVTV_REG_DMASTATUS) & 3, IVTV_REG_DMASTATUS);
+                               status, itv->cur_dma_stream);
+       /*
+        * We do *not* write back to the IVTV_REG_DMASTATUS register to
+        * clear the error status, if either the encoder write (0x02) or
+        * decoder read (0x01) bus master DMA operation do not indicate
+        * completed.  We can race with the DMA engine, which may have
+        * transitioned to completed status *after* we read the register.
+        * Setting a IVTV_REG_DMASTATUS flag back to "busy" status, after the
+        * DMA engine has completed, will cause the DMA engine to stop working.
+        */
+       status &= 0x3;
+       if (status == 0x3)
+               write_reg(status, IVTV_REG_DMASTATUS);
+
        if (!test_bit(IVTV_F_I_UDMA, &itv->i_flags) &&
            itv->cur_dma_stream >= 0 && itv->cur_dma_stream < IVTV_MAX_STREAMS) {
                struct ivtv_stream *s = &itv->streams[itv->cur_dma_stream];
 
-               /* retry */
-               if (s->type >= IVTV_DEC_STREAM_TYPE_MPG)
+               if (s->type >= IVTV_DEC_STREAM_TYPE_MPG) {
+                       /* retry */
+                       /*
+                        * FIXME - handle cases of DMA error similar to
+                        * encoder below, except conditioned on status & 0x1
+                        */
                        ivtv_dma_dec_start(s);
-               else
-                       ivtv_dma_enc_start(s);
-               return;
+                       return;
+               } else {
+                       if ((status & 0x2) == 0) {
+                               /*
+                                * CX2341x Bus Master DMA write is ongoing.
+                                * Reset the timer and let it complete.
+                                */
+                               itv->dma_timer.expires =
+                                               jiffies + msecs_to_jiffies(600);
+                               add_timer(&itv->dma_timer);
+                               return;
+                       }
+
+                       if (itv->dma_retries < 3) {
+                               /*
+                                * CX2341x Bus Master DMA write has ended.
+                                * Retry the write, starting with the first
+                                * xfer segment. Just retrying the current
+                                * segment is not sufficient.
+                                */
+                               s->sg_processed = 0;
+                               itv->dma_retries++;
+                               ivtv_dma_enc_start_xfer(s);
+                               return;
+                       }
+                       /* Too many retries, give up on this one */
+               }
+
        }
        if (test_bit(IVTV_F_I_UDMA, &itv->i_flags)) {
                ivtv_udma_start(itv);