esp.c: only transfer non-DMA COMMAND phase data for specific commands

The contents of the FIFO should only be copied to cmdfifo for ESP commands that
are sending data to the SCSI bus, which are the SEL_* commands and the TI
command. Otherwise any incoming data should be held in the FIFO as normal.

This fixes booting of really old 32-bit SPARC Linux kernels such as Aurelien's
debian_etch_sparc_small.qcow2 test image.

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: <20240112125420.514425-77-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 ca26415d5fb57027ab28bab21e1d6589d1570f32..17e2db442c82d48016fd99d5bc3069c4817c676f 100644 (file)
--- a/hw/scsi/esp.c
+++ b/hw/scsi/esp.c
@@ -757,13 +757,13 @@ static void esp_do_nodma(ESPState *s)
         break;
 
     case STAT_CD:
-        /* Copy FIFO into cmdfifo */
-        n = esp_fifo_pop_buf(&s->fifo, buf, fifo8_num_used(&s->fifo));
-        n = MIN(fifo8_num_free(&s->cmdfifo), n);
-        fifo8_push_all(&s->cmdfifo, buf, n);
-
         switch (s->rregs[ESP_CMD]) {
         case CMD_TI:
+            /* Copy FIFO into cmdfifo */
+            n = esp_fifo_pop_buf(&s->fifo, buf, fifo8_num_used(&s->fifo));
+            n = MIN(fifo8_num_free(&s->cmdfifo), n);
+            fifo8_push_all(&s->cmdfifo, buf, n);
+
             cmdlen = fifo8_num_used(&s->cmdfifo);
             trace_esp_handle_ti_cmd(cmdlen);
 
@@ -788,6 +788,11 @@ static void esp_do_nodma(ESPState *s)
 
         case CMD_SEL | CMD_DMA:
         case CMD_SELATN | CMD_DMA:
+            /* Copy FIFO into cmdfifo */
+            n = esp_fifo_pop_buf(&s->fifo, buf, fifo8_num_used(&s->fifo));
+            n = MIN(fifo8_num_free(&s->cmdfifo), n);
+            fifo8_push_all(&s->cmdfifo, buf, n);
+
             /* Handle when DMA transfer is terminated by non-DMA FIFO write */
             if (esp_cdb_length(s) && esp_cdb_length(s) ==
                 fifo8_num_used(&s->cmdfifo) - s->cmdfifo_cdb_offset) {
@@ -798,7 +803,11 @@ static void esp_do_nodma(ESPState *s)
 
         case CMD_SEL:
         case CMD_SELATN:
-            /* FIFO already contain entire CDB */
+            /* FIFO already contain entire CDB: copy to cmdfifo and execute */
+            n = esp_fifo_pop_buf(&s->fifo, buf, fifo8_num_used(&s->fifo));
+            n = MIN(fifo8_num_free(&s->cmdfifo), n);
+            fifo8_push_all(&s->cmdfifo, buf, n);
+
             do_cmd(s);
             break;
         }