ahci: fix signature generation

The initial register device-to-host FIS no longer needs to specially
set certain fields, as these can be handled generically by setting those
fields explicitly with the signatures we want at port reset time.

(1) Signatures are decomposed into their four component registers and
    set upon (AHCI) port reset.
(2) the signature cache register is no longer set manually per-each
    device type, but instead just once during ahci_init_d2h.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1441140641-17631-3-git-send-email-jsnow@redhat.com

hw/ide/ahci.c

@@ -540,20 +540,31 @@ static void ahci_init_d2h(AHCIDevice *ad)
 {
     uint8_t init_fis[20];
     IDEState *ide_state = &ad->port.ifs[0];
+    AHCIPortRegs *pr = &ad->port_regs;
 
     memset(init_fis, 0, sizeof(init_fis));
 
-    init_fis[4] = 1;
-    init_fis[12] = 1;
-
-    if (ide_state->drive_kind == IDE_CD) {
-        init_fis[5] = ide_state->lcyl;
-        init_fis[6] = ide_state->hcyl;
-    }
+    /* We're emulating receiving the first Reg H2D Fis from the device;
+     * Update the SIG register, but otherwise proceed as normal. */
+    pr->sig = (ide_state->hcyl << 24) |
+        (ide_state->lcyl << 16) |
+        (ide_state->sector << 8) |
+        (ide_state->nsector & 0xFF);
 
     ahci_write_fis_d2h(ad, init_fis);
 }
 
+static void ahci_set_signature(AHCIDevice *ad, uint32_t sig)
+{
+    IDEState *s = &ad->port.ifs[0];
+    s->hcyl = sig >> 24 & 0xFF;
+    s->lcyl = sig >> 16 & 0xFF;
+    s->sector = sig >> 8 & 0xFF;
+    s->nsector = sig & 0xFF;
+
+    DPRINTF(ad->port_no, "set hcyl:lcyl:sect:nsect = 0x%08x\n", sig);
+}
+
 static void ahci_reset_port(AHCIState *s, int port)
 {
     AHCIDevice *d = &s->dev[port];
@@ -603,13 +614,10 @@ static void ahci_reset_port(AHCIState *s, int port)
 
     s->dev[port].port_state = STATE_RUN;
     if (ide_state->drive_kind == IDE_CD) {
-        pr->sig = SATA_SIGNATURE_CDROM;
-        ide_state->lcyl = 0x14;
-        ide_state->hcyl = 0xeb;
-        DPRINTF(port, "set lcyl = %d\n", ide_state->lcyl);
+        ahci_set_signature(d, SATA_SIGNATURE_CDROM);\
         ide_state->status = SEEK_STAT | WRERR_STAT | READY_STAT;
     } else {
-        pr->sig = SATA_SIGNATURE_DISK;
+        ahci_set_signature(d, SATA_SIGNATURE_DISK);
         ide_state->status = SEEK_STAT | WRERR_STAT;
     }