ssb: Handle alternate SSPROM location

In kernel Bugzilla #15825 (2 users), in a wireless mailing list thread
(http://lists.infradead.org/pipermail/b43-dev/2010-May/000124.html), and on a
netbook owned by John Linville
(http://marc.info/?l=linux-wireless&m=127230751408818&w=4), there are reports
of ssb failing to detect an SPROM at the normal location. After studying the
MMIO trace dump for the Broadcom wl driver, it was determined that the affected
boxes had a relocated SPROM.

This patch fixes all systems that have reported this problem.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Stable <stable@kernel.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/ssb/driver_chipcommon.c

@@ -259,6 +259,7 @@ void ssb_chipcommon_init(struct ssb_chipcommon *cc)
 		return; /* We don't have a ChipCommon */
 	if (cc->dev->id.revision >= 11)
 		cc->status = chipco_read32(cc, SSB_CHIPCO_CHIPSTAT);
+	ssb_dprintk(KERN_INFO PFX "chipcommon status is 0x%x\n", cc->status);
 	ssb_pmu_init(cc);
 	chipco_powercontrol_init(cc);
 	ssb_chipco_set_clockmode(cc, SSB_CLKMODE_FAST);

drivers/ssb/pci.c

@@ -626,11 +626,22 @@ static int ssb_pci_sprom_get(struct ssb_bus *bus,
 		return -ENODEV;
 	}
 	if (bus->chipco.dev) {	/* can be unavailible! */
-		bus->sprom_offset = (bus->chipco.dev->id.revision < 31) ?
-			SSB_SPROM_BASE1 : SSB_SPROM_BASE31;
+		/*
+		 * get SPROM offset: SSB_SPROM_BASE1 except for
+		 * chipcommon rev >= 31 or chip ID is 0x4312 and
+		 * chipcommon status & 3 == 2
+		 */
+		if (bus->chipco.dev->id.revision >= 31)
+			bus->sprom_offset = SSB_SPROM_BASE31;
+		else if (bus->chip_id == 0x4312 &&
+			 (bus->chipco.status & 0x03) == 2)
+			bus->sprom_offset = SSB_SPROM_BASE31;
+		else
+			bus->sprom_offset = SSB_SPROM_BASE1;
 	} else {
 		bus->sprom_offset = SSB_SPROM_BASE1;
 	}
+	ssb_dprintk(KERN_INFO PFX "SPROM offset is 0x%x\n", bus->sprom_offset);
 
 	buf = kcalloc(SSB_SPROMSIZE_WORDS_R123, sizeof(u16), GFP_KERNEL);
 	if (!buf)