[Qemu-devel] [PATCHv2] esp: Do not overwrite ESP_TCHI after reset

[Hannes Reinecke <hare@suse.de>]

After a reset ESP_TCHI should contain the unique ID
of the chip. This value will be overwritten with the
current tranfer count if the transfer count has
previously been set.
So we should always return the chip id if ESP_TCHI
has never been written to.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 hw/scsi/esp.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c
index 5ab44d8..2caac1c 100644
--- a/hw/scsi/esp.c
+++ b/hw/scsi/esp.c
@@ -364,7 +364,6 @@ void esp_hard_reset(ESPState *s)
 {
     memset(s->rregs, 0, ESP_REGS);
     memset(s->wregs, 0, ESP_REGS);
-    s->rregs[ESP_TCHI] = s->chip_id;
     s->ti_size = 0;
     s->ti_rptr = 0;
     s->ti_wptr = 0;
@@ -422,6 +421,11 @@ uint64_t esp_reg_read(ESPState *s, uint32_t saddr)
         esp_lower_irq(s);
 
         return old_val;
+    case ESP_TCHI:
+        /* Return the unique id if the value has never been written */
+        if (!s->wregs[ESP_TCHI]) {
+            return s->chip_id;
+        }
     default:
         break;
     }
-- 
1.7.12.4