Revert "mtd: spi-nor: fix setting of SNOR_LAST_REGION bit"

This reverts commit 908bf46.

There are slightly different changes between what we applied back in
linux4sam-6.0 and what reached mainline. Revert the 4BAIT, SMPT and
non-uniform erase support and backport the support and fixes from
mainline.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>

Author: ambarus

drivers/mtd/spi-nor/spi-nor.c

@@ -2413,9 +2413,8 @@ static inline void
 spi_nor_init_uniform_erase_map(struct spi_nor_erase_map *map,
 			       u8 erase_mask, u64 flash_size)
 {
-	/* Offset 0 with erase_mask and SNOR_LAST_REGION bit set */
-	map->uniform_region.offset = (erase_mask & SNOR_ERASE_TYPE_MASK) |
-				     SNOR_LAST_REGION;
+	map->uniform_region.offset = SNOR_ERASE_FLAGS_OFFSET(erase_mask, 1, 0,
+							     0);
 	map->uniform_region.size = flash_size;
 	map->regions = &map->uniform_region;
 	map->uniform_erase_type = erase_mask;

include/linux/mtd/spi-nor.h

@@ -296,6 +296,13 @@ struct spi_nor_erase_region {
 #define SNOR_ERASE_FLAGS_MAX	6
 #define SNOR_ERASE_FLAGS_MASK	GENMASK_ULL(SNOR_ERASE_FLAGS_MAX - 1, 0)
 
+#define SNOR_ERASE_FLAGS_OFFSET(_cmd_mask, _last_region, _overlaid_region, \
+				_offset)				\
+	((((u64)(_offset)) & ~SNOR_ERASE_FLAGS_MASK)	|		\
+	 (((u64)(_cmd_mask)) & SNOR_ERASE_TYPE_MASK)	|		\
+	 (((u64)(_last_region)) & SNOR_LAST_REGION)	|		\
+	 (((u64)(_overlaid_region)) & SNOR_OVERLAID_REGION))
+
 /**
  * struct spi_nor_erase_map - Structure to describe the SPI NOR erase map
  * @regions:		array of erase regions. The regions are consecutive in