[PATCH] lsi53c895a: Add missing registers and workaround for OS/2 Warp SYM8XX.ADD driver

["Nicholas A. Bellinger" <nab@linux-iscsi.org>]

From: Nicholas Bellinger <nab@linux-iscsi.org>

This patch adds support for using lsi53c895a HBA with SYM8XXX.ADD driver v4.10.
This includes adding the missing SOCL and STIME1 registers from lsi_reg_readb(),
and missing SOCL and a workaround for bogus SDID WRITE that is requred to
function with the SYM8XXX.ADD driver.

Note that this patch also includes ISTAT1 in lsi_reg_writeb(), which currently
will BADF() as this register is (supposed) to be reserved for 53c896 silicon.
Note that the other lsi53c895a capable driver from LSI (SYM_HI.ADD) currently
tries to read these, even though we are reporting PCI_DEVICE_ID_LSI_53C895A.

So far this patch is able to successfully boot OS/2 Warp v4 (SP15) and complete
the LUN scan with a scsi-generic <-> TCM_Loop + TCM/FILEIO connected LUN running
on TCM/KVM host.

Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
---
 hw/lsi53c895a.c |   26 ++++++++++++++++++++++----
 1 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/hw/lsi53c895a.c b/hw/lsi53c895a.c
index 983f6cb..87e1a04 100644
--- a/hw/lsi53c895a.c
+++ b/hw/lsi53c895a.c
@@ -437,8 +437,8 @@ static void lsi_update_irq(LSIState *s)
         level = 1;
 
     if (level != last_level) {
-        DPRINTF("Update IRQ level %d dstat %02x sist %02x%02x\n",
-                level, s->dstat, s->sist1, s->sist0);
+        DPRINTF("Update IRQ level %d dstat %02x sist %02x%02x, istat: %02x%02x\n",
+                level, s->dstat, s->sist1, s->sist0, s->istat1, s->istat0);
         last_level = level;
     }
     qemu_set_irq(s->dev.irq[0], level);
@@ -1425,6 +1425,8 @@ static uint8_t lsi_reg_readb(LSIState *s, int offset)
         return 0x7f;
     case 0x08: /* Revision ID */
         return 0x00;
+    case 0x09: /* SOCL */
+        return s->socl;
     case 0xa: /* SSID */
         return s->ssid;
     case 0xb: /* SBCL */
@@ -1509,6 +1511,10 @@ static uint8_t lsi_reg_readb(LSIState *s, int offset)
         return 0x0f;
     case 0x48: /* STIME0 */
         return s->stime0;
+    case 0x49: /* STIME1 */
+        /* Generate purpose timer, disabled by default in the Linux driver
+           and  required for the OS/2 SYM_HI.ADD driver  */
+        return 0;
     case 0x4a: /* RESPID0 */
         return s->respid0;
     case 0x4b: /* RESPID1 */
@@ -1625,8 +1631,14 @@ static void lsi_reg_writeb(LSIState *s, int offset, uint8_t val)
         s->sxfer = val;
         break;
     case 0x06: /* SDID */
-        if ((val & 0xf) != (s->ssid & 0xf))
-            BADF("Destination ID does not match SSID\n");
+        /*
+         * This workaround is required by the SYM8XX.ADD driver for OS/2 Warp.
+         */
+        if ((val & 0xf) != (s->ssid & 0xf)) {
+            DPRINTF("Destination ID does not match SSID, val: %02x"
+                    " s->ssid: %02x, fixing up val\n", val, s->ssid);
+            val = s->ssid;
+        }
         s->sdid = val & 0xf;
         break;
     case 0x07: /* GPREG0 */
@@ -1636,6 +1648,9 @@ static void lsi_reg_writeb(LSIState *s, int offset, uint8_t val)
            SCRIPTS register move instructions are.  */
         s->sfbr = val;
         break;
+    case 0x09: /* SOCL - SCSI Output Control Latch */
+        s->socl = val; 
+        break;
     case 0x0a: case 0x0b:
         /* Openserver writes to these readonly registers on startup */
 	return;
@@ -1662,6 +1677,9 @@ static void lsi_reg_writeb(LSIState *s, int offset, uint8_t val)
             lsi_soft_reset(s);
         }
         break;
+    case 0x15: /* ISTAT1 */
+        BADF(" ISTAT1 not implemented for 53c896 silicon");
+        break;
     case 0x16: /* MBOX0 */
         s->mbox0 = val;
         break;
-- 
1.5.6.5