mtd: spi-nor: core: get rid of SNOR_LAST_REGION flag

Introduce n_regions in spi_nor_erase_map structure and remove
SNOR_LAST_REGION flag. Loop logics that depend on the flag are also
reworked to use n_regions as loop condition.

Signed-off-by: Takahiro Kuwano <Takahiro.Kuwano@infineon.com>
Suggested-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Suggested-by: Michael Walle <mwalle@kernel.org>
Reviewed-by: Michael Walle <mwalle@kernel.org>
Link: https://lore.kernel.org/r/eded84294bd81e966d6f423e578fc2cfb9a4a5b6.1708404584.git.Takahiro.Kuwano@infineon.com
[ta: update spi_nor_init_erase_cmd_list() and break the for loop sooner.]
Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>

Author: Kuwano-san

drivers/mtd/spi-nor/core.c

@@ -1573,52 +1573,6 @@ spi_nor_find_best_erase_type(const struct spi_nor_erase_map *map,
 	return NULL;
 }
 
-static u64 spi_nor_region_is_last(const struct spi_nor_erase_region *region)
-{
-	return region->flags & SNOR_LAST_REGION;
-}
-
-/**
- * spi_nor_region_next() - get the next spi nor region
- * @region:	pointer to a structure that describes a SPI NOR erase region
- *
- * Return: the next spi nor region or NULL if last region.
- */
-struct spi_nor_erase_region *
-spi_nor_region_next(struct spi_nor_erase_region *region)
-{
-	if (spi_nor_region_is_last(region))
-		return NULL;
-	region++;
-	return region;
-}
-
-/**
- * spi_nor_find_erase_region() - find the region of the serial flash memory in
- *				 which the offset fits
- * @map:	the erase map of the SPI NOR
- * @addr:	offset in the serial flash memory
- *
- * Return: a pointer to the spi_nor_erase_region struct, ERR_PTR(-errno)
- *	   otherwise.
- */
-static struct spi_nor_erase_region *
-spi_nor_find_erase_region(const struct spi_nor_erase_map *map, u64 addr)
-{
-	struct spi_nor_erase_region *region = map->regions;
-	u64 region_end = region->offset + region->size;
-
-	while (addr < region->offset || addr >= region_end) {
-		region = spi_nor_region_next(region);
-		if (!region)
-			return ERR_PTR(-EINVAL);
-
-		region_end = region->offset + region->size;
-	}
-
-	return region;
-}
-
 /**
  * spi_nor_init_erase_cmd() - initialize an erase command
  * @region:	pointer to a structure that describes a SPI NOR erase region
@@ -1685,44 +1639,36 @@ static int spi_nor_init_erase_cmd_list(struct spi_nor *nor,
 	struct spi_nor_erase_region *region;
 	struct spi_nor_erase_command *cmd = NULL;
 	u64 region_end;
+	unsigned int i;
 	int ret = -EINVAL;
 
-	region = spi_nor_find_erase_region(map, addr);
-	if (IS_ERR(region))
-		return PTR_ERR(region);
-
-	region_end = region->offset + region->size;
+	for (i = 0; i < map->n_regions && len; i++) {
+		region = &map->regions[i];
+		region_end = region->offset + region->size;
 
-	while (len) {
-		erase = spi_nor_find_best_erase_type(map, region, addr, len);
-		if (!erase)
-			goto destroy_erase_cmd_list;
-
-		if (prev_erase != erase ||
-		    erase->size != cmd->size ||
-		    region->flags & SNOR_OVERLAID_REGION) {
-			cmd = spi_nor_init_erase_cmd(region, erase);
-			if (IS_ERR(cmd)) {
-				ret = PTR_ERR(cmd);
+		while (len && addr >= region->offset && addr < region_end) {
+			erase = spi_nor_find_best_erase_type(map, region, addr,
+							     len);
+			if (!erase)
 				goto destroy_erase_cmd_list;
-			}
-
-			list_add_tail(&cmd->list, erase_list);
-		} else {
-			cmd->count++;
-		}
 
-		addr += cmd->size;
-		len -= cmd->size;
+			if (prev_erase != erase || erase->size != cmd->size ||
+			    region->flags & SNOR_OVERLAID_REGION) {
+				cmd = spi_nor_init_erase_cmd(region, erase);
+				if (IS_ERR(cmd)) {
+					ret = PTR_ERR(cmd);
+					goto destroy_erase_cmd_list;
+				}
+
+				list_add_tail(&cmd->list, erase_list);
+			} else {
+				cmd->count++;
+			}
 
-		if (len && addr >= region_end) {
-			region = spi_nor_region_next(region);
-			if (!region)
-				goto destroy_erase_cmd_list;
-			region_end = region->offset + region->size;
+			len -= cmd->size;
+			addr += cmd->size;
+			prev_erase = erase;
 		}
-
-		prev_erase = erase;
 	}
 
 	return 0;
@@ -2463,8 +2409,8 @@ void spi_nor_init_uniform_erase_map(struct spi_nor_erase_map *map,
 	map->uniform_region.offset = 0;
 	map->uniform_region.size = flash_size;
 	map->uniform_region.erase_mask = erase_mask;
-	map->uniform_region.flags = SNOR_LAST_REGION;
 	map->regions = &map->uniform_region;
+	map->n_regions = 1;
 }
 
 int spi_nor_post_bfpt_fixups(struct spi_nor *nor,

drivers/mtd/spi-nor/core.h

@@ -245,8 +245,7 @@ struct spi_nor_erase_command {
  *			inside this region. The erase types are sorted in
  *			ascending order with the smallest Erase Type size being
  *			at BIT(0).
- * @flags:		flags to determine if this region is overlaid, if this
- *			region is the last in the SPI NOR flash memory
+ * @flags:		flags to determine if this region is overlaid.
  */
 struct spi_nor_erase_region {
 	u64		offset;
@@ -257,8 +256,7 @@ struct spi_nor_erase_region {
 
 #define SNOR_ERASE_TYPE_MAX	4
 
-#define SNOR_LAST_REGION	BIT(0)
-#define SNOR_OVERLAID_REGION	BIT(1)
+#define SNOR_OVERLAID_REGION	BIT(0)
 
 /**
  * struct spi_nor_erase_map - Structure to describe the SPI NOR erase map
@@ -271,11 +269,13 @@ struct spi_nor_erase_region {
  *			The erase types are sorted in ascending order, with the
  *			smallest Erase Type size being the first member in the
  *			erase_type array.
+ * @n_regions:		number of erase regions.
  */
 struct spi_nor_erase_map {
 	struct spi_nor_erase_region	*regions;
 	struct spi_nor_erase_region	uniform_region;
 	struct spi_nor_erase_type	erase_type[SNOR_ERASE_TYPE_MAX];
+	unsigned int			n_regions;
 };
 
 /**
@@ -667,8 +667,6 @@ void spi_nor_set_pp_settings(struct spi_nor_pp_command *pp, u8 opcode,
 void spi_nor_set_erase_type(struct spi_nor_erase_type *erase, u32 size,
 			    u8 opcode);
 void spi_nor_mask_erase_type(struct spi_nor_erase_type *erase);
-struct spi_nor_erase_region *
-spi_nor_region_next(struct spi_nor_erase_region *region);
 void spi_nor_init_uniform_erase_map(struct spi_nor_erase_map *map,
 				    u8 erase_mask, u64 flash_size);
 

drivers/mtd/spi-nor/debugfs.c

@@ -78,10 +78,10 @@ static int spi_nor_params_show(struct seq_file *s, void *data)
 	struct spi_nor *nor = s->private;
 	struct spi_nor_flash_parameter *params = nor->params;
 	struct spi_nor_erase_map *erase_map = &params->erase_map;
-	struct spi_nor_erase_region *region;
+	struct spi_nor_erase_region *region = erase_map->regions;
 	const struct flash_info *info = nor->info;
 	char buf[16], *str;
-	int i;
+	unsigned int i;
 
 	seq_printf(s, "name\t\t%s\n", info->name);
 	seq_printf(s, "id\t\t%*ph\n", SPI_NOR_MAX_ID_LEN, nor->id);
@@ -144,13 +144,11 @@ static int spi_nor_params_show(struct seq_file *s, void *data)
 	seq_puts(s, "\nsector map\n");
 	seq_puts(s, " region (in hex)   | erase mask | flags\n");
 	seq_puts(s, " ------------------+------------+----------\n");
-	for (region = erase_map->regions;
-	     region;
-	     region = spi_nor_region_next(region)) {
-		u64 start = region->offset;
-		u64 end = start + region->size - 1;
-		u8 erase_mask = region->erase_mask;
-		u8 flags = region->flags;
+	for (i = 0; i < erase_map->n_regions; i++) {
+		u64 start = region[i].offset;
+		u64 end = start + region[i].size - 1;
+		u8 erase_mask = region[i].erase_mask;
+		u8 flags = region[i].flags;
 
 		seq_printf(s, " %08llx-%08llx |     [%c%c%c%c] | %s\n",
 			   start, end,

drivers/mtd/spi-nor/sfdp.c

@@ -390,15 +390,14 @@ static void spi_nor_regions_sort_erase_types(struct spi_nor_erase_map *map)
 {
 	struct spi_nor_erase_region *region = map->regions;
 	u8 sorted_erase_mask;
+	unsigned int i;
 
-	while (region) {
-		sorted_erase_mask = spi_nor_sort_erase_mask(map,
-							    region->erase_mask);
+	for (i = 0; i < map->n_regions; i++) {
+		sorted_erase_mask =
+			spi_nor_sort_erase_mask(map, region[i].erase_mask);
 
 		/* Overwrite erase mask. */
-		region->erase_mask = sorted_erase_mask;
-
-		region = spi_nor_region_next(region);
+		region[i].erase_mask = sorted_erase_mask;
 	}
 }
 
@@ -801,11 +800,6 @@ static const u32 *spi_nor_get_map_in_use(struct spi_nor *nor, const u32 *smpt,
 	return ret;
 }
 
-static void spi_nor_region_mark_end(struct spi_nor_erase_region *region)
-{
-	region->flags |= SNOR_LAST_REGION;
-}
-
 static void spi_nor_region_mark_overlay(struct spi_nor_erase_region *region)
 {
 	region->flags |= SNOR_OVERLAID_REGION;
@@ -863,6 +857,7 @@ static int spi_nor_init_non_uniform_erase_map(struct spi_nor *nor,
 	if (!region)
 		return -ENOMEM;
 	map->regions = region;
+	map->n_regions = region_count;
 
 	uniform_erase_type = 0xff;
 	regions_erase_type = 0;
@@ -891,7 +886,6 @@ static int spi_nor_init_non_uniform_erase_map(struct spi_nor *nor,
 
 		offset = region[i].offset + region[i].size;
 	}
-	spi_nor_region_mark_end(&region[i - 1]);
 
 	save_uniform_erase_type = map->uniform_region.erase_mask;
 	map->uniform_region.erase_mask =