[PATCH] Revised the detection for broken boot-region detection. MACRONIX parts have a custom implementation of the fixup. AMD implemtation restore to original version that has worked fine since 2001.

["Marc Singer" <elf@synapse.com>]

Signed-off-by: Marc Singer <elf@zealous.synapse.com>
---
 drivers/mtd/chips/cfi_cmdset_0002.c |   96 ++++++++++++++++++++++-------------
 1 files changed, 60 insertions(+), 36 deletions(-)

diff --git a/drivers/mtd/chips/cfi_cmdset_0002.c b/drivers/mtd/chips/cfi_cmdset_0002.c
index d74ec46..4f1b445 100644
--- a/drivers/mtd/chips/cfi_cmdset_0002.c
+++ b/drivers/mtd/chips/cfi_cmdset_0002.c
@@ -136,7 +136,21 @@ static void cfi_tell_features(struct cfi_pri_amdstd *extp)
 #endif
 
 #ifdef AMD_BOOTLOC_BUG
-/* Wheee. Bring me the head of someone at AMD. */
+/* Wheee. Bring me the head of someone at AMD,
+   and another from Macronix...just for good measure. */
+
+/* Some early AMD NOR flash parts (AM29LV160D, e.g.) and much
+ * more recent and inexcusably broken Macronix parts, do not
+ * accurately report whether or not the device is top-boot or
+ * bottom-boot in the CFI PRI data.  This detail is important
+ * to correctly sort the erase region information.  So, for
+ * CFI versions < 1.1 where we do not trust the veracity of
+ * the CFI PRI data, we look for explicit manufacturer/device
+ * IDs when we know them or for the high bit of the device ID.
+ * The latter test has been working reliably since 2001 even
+ * though we don't have documentation to support this as a
+ * convention. */
+
 static void fixup_amd_bootblock(struct mtd_info *mtd, void* param)
 {
 	struct map_info *map = mtd->priv;
@@ -148,43 +162,53 @@ static void fixup_amd_bootblock(struct mtd_info *mtd, void* param)
 	if (((major << 8) | minor) < 0x3131) {
 		/* CFI version 1.0 => don't trust bootloc */
 
+                extp->TopBottom = (cfi->id & 0x80)
+                        ? 3 /* top-boot */
+                        : 2 /* bottom-boot */;
+
 		DEBUG(MTD_DEBUG_LEVEL1,
-			"%s: JEDEC Vendor ID is 0x%02X Device ID is 0x%02X\n",
-			map->name, cfi->mfr, cfi->id);
+                      "%s: CFI PRI V%c.%c has no boot block field;"
+                      " deduced %s from Mfr/Device ID %0x/%0x\n",
+                      map->name, major, minor,
+                      extp->TopBottom == 2 ? "bottom" : "top",
+                      cfi->mfr, cfi->id);
+	}
+}
 
-		/* AFAICS all 29LV400 with a bottom boot block have a device ID
-		 * of 0x22BA in 16-bit mode and 0xBA in 8-bit mode.
-		 * These were badly detected as they have the 0x80 bit set
-		 * so treat them as a special case.
-		 */
-		if (((cfi->id == 0xBA) || (cfi->id == 0x22BA)) &&
-
-			/* Macronix added CFI to their 2nd generation
-			 * MX29LV400C B/T but AFAICS no other 29LV400 (AMD,
-			 * Fujitsu, Spansion, EON, ESI and older Macronix)
-			 * has CFI.
-			 *
-			 * Therefore also check the manufacturer.
-			 * This reduces the risk of false detection due to
-			 * the 8-bit device ID.
-			 */
-			(cfi->mfr == MANUFACTURER_MACRONIX)) {
-			DEBUG(MTD_DEBUG_LEVEL1,
-				"%s: Macronix MX29LV400C with bottom boot block"
-				" detected\n", map->name);
-			extp->TopBottom = 2;	/* bottom boot */
-		} else
-		if (cfi->id & 0x80) {
-			printk(KERN_WARNING "%s: JEDEC Device ID is 0x%02X. Assuming broken CFI table.\n", map->name, cfi->id);
-			extp->TopBottom = 3;	/* top boot */
-		} else {
-			extp->TopBottom = 2;	/* bottom boot */
-		}
+static void fixup_macronix_bootblock(struct mtd_info *mtd, void* param)
+{
+	struct map_info *map = mtd->priv;
+	struct cfi_private *cfi = map->fldrv_priv;
+	struct cfi_pri_amdstd *extp = cfi->cmdset_priv;
+	__u8 major = extp->MajorVersion;
+	__u8 minor = extp->MinorVersion;
+
+	if (((major << 8) | minor) < 0x3131) {
+		/* CFI version 1.0 => don't trust bootloc */
 
+                switch (cfi->id) {
+                                /* Macronix MX29LV400CT */
+                case 0x00ba:
+                case 0x22ba:
+                        extp->TopBottom = 2;                 /* bottom-boot */
+                        break;
+                        	/* Macronix MX29LV400CB */
+                case 0x00b9:
+                case 0x22b9:
+                        extp->TopBottom = 3;                 /* top-boot */
+                        break;
+                default:
+                                /* Fall back is to assume we have
+                                 * bottom-boot. */
+                        extp->TopBottom = 2; /* bottom-boot */
+                        break;
+                }
 		DEBUG(MTD_DEBUG_LEVEL1,
-			"%s: AMD CFI PRI V%c.%c has no boot block field;"
-			" deduced %s from Device ID\n", map->name, major, minor,
-			extp->TopBottom == 2 ? "bottom" : "top");
+                      "%s: CFI PRI V%c.%c has no boot block field;"
+                      " deduced %s from Mfr/Device ID %0x/%0x\n",
+                      map->name, major, minor,
+                      extp->TopBottom == 2 ? "bottom" : "top",
+                      cfi->mfr, cfi->id);
 	}
 }
 #endif
@@ -286,7 +310,7 @@ static struct cfi_fixup cfi_fixup_table[] = {
 	{ CFI_MFR_ATMEL, CFI_ID_ANY, fixup_convert_atmel_pri, NULL },
 #ifdef AMD_BOOTLOC_BUG
 	{ CFI_MFR_AMD, CFI_ID_ANY, fixup_amd_bootblock, NULL },
-	{ MANUFACTURER_MACRONIX, CFI_ID_ANY, fixup_amd_bootblock, NULL },
+	{ MANUFACTURER_MACRONIX, CFI_ID_ANY, fixup_macronix_bootblock, NULL },
 #endif
 	{ CFI_MFR_AMD, 0x0050, fixup_use_secsi, NULL, },
 	{ CFI_MFR_AMD, 0x0053, fixup_use_secsi, NULL, },
-- 
1.5.6.5