esp: move handle_ti_cmd() cleanup code to esp_do_dma().

To prepare following patches move do_cmd and DMA special case
from handle_ti() to esp_do_dma().

This part of the code must be only executed with real DMA, not with
pseudo-DMA. And PDMA is detected in esp_do_dma(), so move this part
of the code in esp_do_dma(). We keep the code in handle_ti_cmd()
in the case no DMA is done.

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20191026164546.30020-2-laurent@vivier.eu>

hw/scsi/esp.c

@@ -249,10 +249,19 @@ static void esp_do_dma(ESPState *s)
 
     len = s->dma_left;
     if (s->do_cmd) {
+        /*
+         * handle_ti_cmd() case: esp_do_dma() is called only from
+         * handle_ti_cmd() with do_cmd != NULL (see the assert())
+         */
         trace_esp_do_dma(s->cmdlen, len);
         assert (s->cmdlen <= sizeof(s->cmdbuf) &&
                 len <= sizeof(s->cmdbuf) - s->cmdlen);
         s->dma_memory_read(s->dma_opaque, &s->cmdbuf[s->cmdlen], len);
+        trace_esp_handle_ti_cmd(s->cmdlen);
+        s->ti_size = 0;
+        s->cmdlen = 0;
+        s->do_cmd = 0;
+        do_cmd(s, s->cmdbuf);
         return;
     }
     if (s->async_len == 0) {
@@ -373,8 +382,7 @@ static void handle_ti(ESPState *s)
         s->dma_left = minlen;
         s->rregs[ESP_RSTAT] &= ~STAT_TC;
         esp_do_dma(s);
-    }
-    if (s->do_cmd) {
+    } else if (s->do_cmd) {
         trace_esp_handle_ti_cmd(s->cmdlen);
         s->ti_size = 0;
         s->cmdlen = 0;