diff options
| -rw-r--r-- | hw/scsi/esp.c | 20 |
1 files changed, 13 insertions, 7 deletions
diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c index 62ba406149..ec9fcbeddf 100644 --- a/hw/scsi/esp.c +++ b/hw/scsi/esp.c @@ -487,8 +487,10 @@ static void esp_do_dma(ESPState *s) case STAT_MO: if (s->dma_memory_read) { len = MIN(len, fifo8_num_free(&s->cmdfifo)); - s->dma_memory_read(s->dma_opaque, buf, len); - esp_set_tc(s, esp_get_tc(s) - len); + if (len) { + s->dma_memory_read(s->dma_opaque, buf, len); + esp_set_tc(s, esp_get_tc(s) - len); + } } else { len = esp_fifo_pop_buf(s, buf, fifo8_num_used(&s->fifo)); len = MIN(fifo8_num_free(&s->cmdfifo), len); @@ -541,9 +543,11 @@ static void esp_do_dma(ESPState *s) trace_esp_do_dma(cmdlen, len); if (s->dma_memory_read) { len = MIN(len, fifo8_num_free(&s->cmdfifo)); - s->dma_memory_read(s->dma_opaque, buf, len); - fifo8_push_all(&s->cmdfifo, buf, len); - esp_set_tc(s, esp_get_tc(s) - len); + if (len) { + s->dma_memory_read(s->dma_opaque, buf, len); + fifo8_push_all(&s->cmdfifo, buf, len); + esp_set_tc(s, esp_get_tc(s) - len); + } } else { len = esp_fifo_pop_buf(s, buf, fifo8_num_used(&s->fifo)); len = MIN(fifo8_num_free(&s->cmdfifo), len); @@ -572,8 +576,10 @@ static void esp_do_dma(ESPState *s) switch (s->rregs[ESP_CMD]) { case CMD_TI | CMD_DMA: if (s->dma_memory_read) { - s->dma_memory_read(s->dma_opaque, s->async_buf, len); - esp_set_tc(s, esp_get_tc(s) - len); + if (len) { + s->dma_memory_read(s->dma_opaque, s->async_buf, len); + esp_set_tc(s, esp_get_tc(s) - len); + } } else { /* Copy FIFO data to device */ len = MIN(s->async_len, ESP_FIFO_SZ); |