CFI: fix eraseregions numblocks

eraseregions numblocks was sometimes one less than actual, possibly producing
erase regions with zero blocks. As MTD code touches eraseregions only if
numeraseregions is greater that zero, allocate eraseregions only for non
uniform erase size flash.

Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Signed-off-by: Stefan Roese <sr@denx.de>

drivers/mtd/cfi_mtd.c

@@ -161,8 +161,8 @@ static int cfi_mtd_set_erasesize(struct mtd_info *mtd, flash_info_t *fi)
 	int sect;
 	int regions = 0;
 	int numblocks = 0;
-	ulong offset = 0;
-	ulong base_addr = fi->start[0];
+	ulong offset;
+	ulong base_addr;
 
 	/*
 	 * First detect the number of eraseregions so that we can allocate
@@ -174,29 +174,35 @@ static int cfi_mtd_set_erasesize(struct mtd_info *mtd, flash_info_t *fi)
 		sect_size_old = flash_sector_size(fi, sect);
 	}
 
+	switch (regions) {
+	case 0:
+		return 1;
+	case 1:	/* flash has uniform erase size */
+		mtd->numeraseregions = 0;
+		mtd->erasesize = sect_size_old;
+		return 0;
+	}
+
+	mtd->numeraseregions = regions;
 	mtd->eraseregions = malloc(sizeof(struct mtd_erase_region_info) * regions);
 
 	/*
 	 * Now detect the largest sector and fill the eraseregions
 	 */
-	sect_size_old = 0;
 	regions = 0;
+	base_addr = offset = fi->start[0];
+	sect_size_old = flash_sector_size(fi, 0);
 	for (sect = 0; sect < fi->sector_count; sect++) {
-		if ((sect_size_old != flash_sector_size(fi, sect)) &&
-		    (sect_size_old != 0)) {
+		if (sect_size_old != flash_sector_size(fi, sect)) {
 			mtd->eraseregions[regions].offset = offset - base_addr;
 			mtd->eraseregions[regions].erasesize = sect_size_old;
 			mtd->eraseregions[regions].numblocks = numblocks;
-
 			/* Now start counting the next eraseregions */
 			numblocks = 0;
 			regions++;
-		} else {
-			numblocks++;
-		}
-
-		if (sect_size_old != flash_sector_size(fi, sect))
 			offset = fi->start[sect];
+		}
+		numblocks++;
 
 		/*
 		 * Select the largest sector size as erasesize (e.g. for UBI)
@@ -212,12 +218,7 @@ static int cfi_mtd_set_erasesize(struct mtd_info *mtd, flash_info_t *fi)
 	 */
 	mtd->eraseregions[regions].offset = offset - base_addr;
 	mtd->eraseregions[regions].erasesize = sect_size_old;
-	mtd->eraseregions[regions].numblocks = numblocks + 1;
-
-	if (regions)
-		mtd->numeraseregions = regions + 1;
-	else
-		mtd->numeraseregions = 0;
+	mtd->eraseregions[regions].numblocks = numblocks;
 
 	mtd->erasesize = sect_size;