--- 9e50896233aa969e5fa145bcf630dd0ba9055363
+++ 17a178139548c781b4c78e55641b6e0455165b45
@@ -22,6 +22,7 @@
 
 #include "ssb_private.h"
 
+bool ssb_is_sprom_available(struct ssb_bus *bus);
 
 /* Define the following to 1 to enable a printk on each coreswitch. */
 #define SSB_VERBOSE_PCICORESWITCH_DEBUG		0
@@ -167,7 +168,7 @@ err_pci:
 }
 
 /* Get the word-offset for a SSB_SPROM_XXX define. */
-#define SPOFF(offset)	(((offset) - SSB_SPROM_BASE) / sizeof(u16))
+#define SPOFF(offset)	((offset) / sizeof(u16))
 /* Helper to extract some _offset, which is one of the SSB_SPROM_XXX defines. */
 #define SPEX16(_outvar, _offset, _mask, _shift)	\
 	out->_outvar = ((in[SPOFF(_offset)] & (_mask)) >> (_shift))
@@ -252,8 +253,13 @@ static int sprom_do_read(struct ssb_bus
 {
 	int i;
 
+	/* Check if SPROM can be read */
+	if (ioread16(bus->mmio + bus->sprom_offset) == 0xFFFF) {
+		ssb_printk(KERN_ERR PFX "Unable to read SPROM\n");
+		return -ENODEV;
+	}
 	for (i = 0; i < bus->sprom_size; i++)
-		sprom[i] = ioread16(bus->mmio + SSB_SPROM_BASE + (i * 2));
+		sprom[i] = ioread16(bus->mmio + bus->sprom_offset + (i * 2));
 
 	return 0;
 }
@@ -284,7 +290,7 @@ static int sprom_do_write(struct ssb_bus
 			ssb_printk("75%%");
 		else if (i % 2)
 			ssb_printk(".");
-		writew(sprom[i], bus->mmio + SSB_SPROM_BASE + (i * 2));
+		writew(sprom[i], bus->mmio + bus->sprom_offset + (i * 2));
 		mmiowb();
 		msleep(20);
 	}
@@ -620,21 +626,49 @@ static int ssb_pci_sprom_get(struct ssb_
 	int err = -ENOMEM;
 	u16 *buf;
 
+	if (!ssb_is_sprom_available(bus)) {
+		ssb_printk(KERN_ERR PFX "No SPROM available!\n");
+		return -ENODEV;
+	}
+	if (bus->chipco.dev) {	/* can be unavailible! */
+		/*
+		 * 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)
 		goto out;
 	bus->sprom_size = SSB_SPROMSIZE_WORDS_R123;
-	sprom_do_read(bus, buf);
+	err = sprom_do_read(bus, buf);
+	if (err)
+		goto out_free;
 	err = sprom_check_crc(buf, bus->sprom_size);
 	if (err) {
 		/* try for a 440 byte SPROM - revision 4 and higher */
 		kfree(buf);
 		buf = kcalloc(SSB_SPROMSIZE_WORDS_R4, sizeof(u16),
 			      GFP_KERNEL);
-		if (!buf)
+		if (!buf) {
+			err = -ENOMEM;
 			goto out;
+		}
 		bus->sprom_size = SSB_SPROMSIZE_WORDS_R4;
-		sprom_do_read(bus, buf);
+		err = sprom_do_read(bus, buf);
+		if (err)
+			goto out_free;
 		err = sprom_check_crc(buf, bus->sprom_size);
 		if (err) {
 			/* All CRC attempts failed.