esp.c: don't raise INTR_BS interrupt in DATA IN phase until TI command issued

In the case where a SCSI command with a DATA IN phase has been issued, the host
may preload the FIFO with unaligned bytes before issuing the main DMA transfer.

When accumulating data in the FIFO don't raise the INTR_BS interrupt until the
TI command is issued, otherwise the unexpected interrupt can confuse the host.
In particular this is needed to prevent the MacOS Disk Utility from failing
when switching non-DMA transfers to use esp_do_nodma().

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Tested-by: Helge Deller <deller@gmx.de>
Tested-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20240112125420.514425-65-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>

diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c
index bcebd008317ba295dadf193dbbdeb39cb0913b3f..dd6bf6f0335a8f6176f027d10144bfe4e92d32be 100644 (file)
--- a/hw/scsi/esp.c
+++ b/hw/scsi/esp.c
@@ -786,6 +786,11 @@ static void esp_do_nodma(ESPState *s)
             return;
         }
 
+        /* If preloading the FIFO, defer until TI command issued */
+        if (s->rregs[ESP_CMD] != CMD_TI) {
+            return;
+        }
+
         s->rregs[ESP_RINTR] |= INTR_BS;
         esp_raise_irq(s);
         break;