mtd: spi-nor: core: rework struct spi_nor_erase_region

Encoding bitmask flags into offset worsen the code readability. The
erase type mask and flags should be stored in dedicated members. Also,
erase_map.uniform_erase_type can be removed as it is redundant.

Signed-off-by: Takahiro Kuwano <Takahiro.Kuwano@infineon.com>
Suggested-by: Michael Walle <mwalle@kernel.org>
Reviewed-by: Michael Walle <mwalle@kernel.org>
Link: https://lore.kernel.org/r/8e5e9e4081ed9f16ea9dce30693304a4b54d19b1.1708404584.git.Takahiro.Kuwano@infineon.com
[ta: remove spi_nor_region_end()]
Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>

Author: Kuwano-san

drivers/mtd/spi-nor/core.c

@@ -1158,7 +1158,7 @@ static u8 spi_nor_convert_3to4_erase(u8 opcode)
 
 static bool spi_nor_has_uniform_erase(const struct spi_nor *nor)
 {
-	return !!nor->params->erase_map.uniform_erase_type;
+	return !!nor->params->erase_map.uniform_region.erase_mask;
 }
 
 static void spi_nor_set_4byte_opcodes(struct spi_nor *nor)
@@ -1542,23 +1542,22 @@ spi_nor_find_best_erase_type(const struct spi_nor_erase_map *map,
 	const struct spi_nor_erase_type *erase;
 	u32 rem;
 	int i;
-	u8 erase_mask = region->offset & SNOR_ERASE_TYPE_MASK;
 
 	/*
 	 * Erase types are ordered by size, with the smallest erase type at
 	 * index 0.
 	 */
 	for (i = SNOR_ERASE_TYPE_MAX - 1; i >= 0; i--) {
 		/* Does the erase region support the tested erase type? */
-		if (!(erase_mask & BIT(i)))
+		if (!(region->erase_mask & BIT(i)))
 			continue;
 
 		erase = &map->erase_type[i];
 		if (!erase->size)
 			continue;
 
 		/* Alignment is not mandatory for overlaid regions */
-		if (region->offset & SNOR_OVERLAID_REGION &&
+		if (region->flags & SNOR_OVERLAID_REGION &&
 		    region->size <= len)
 			return erase;
 
@@ -1576,12 +1575,7 @@ spi_nor_find_best_erase_type(const struct spi_nor_erase_map *map,
 
 static u64 spi_nor_region_is_last(const struct spi_nor_erase_region *region)
 {
-	return region->offset & SNOR_LAST_REGION;
-}
-
-static u64 spi_nor_region_end(const struct spi_nor_erase_region *region)
-{
-	return (region->offset & ~SNOR_ERASE_FLAGS_MASK) + region->size;
+	return region->flags & SNOR_LAST_REGION;
 }
 
 /**
@@ -1612,16 +1606,14 @@ 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_start = region->offset & ~SNOR_ERASE_FLAGS_MASK;
-	u64 region_end = region_start + region->size;
+	u64 region_end = region->offset + region->size;
 
-	while (addr < region_start || addr >= region_end) {
+	while (addr < region->offset || addr >= region_end) {
 		region = spi_nor_region_next(region);
 		if (!region)
 			return ERR_PTR(-EINVAL);
 
-		region_start = region->offset & ~SNOR_ERASE_FLAGS_MASK;
-		region_end = region_start + region->size;
+		region_end = region->offset + region->size;
 	}
 
 	return region;
@@ -1649,7 +1641,7 @@ spi_nor_init_erase_cmd(const struct spi_nor_erase_region *region,
 	cmd->opcode = erase->opcode;
 	cmd->count = 1;
 
-	if (region->offset & SNOR_OVERLAID_REGION)
+	if (region->flags & SNOR_OVERLAID_REGION)
 		cmd->size = region->size;
 	else
 		cmd->size = erase->size;
@@ -1699,7 +1691,7 @@ static int spi_nor_init_erase_cmd_list(struct spi_nor *nor,
 	if (IS_ERR(region))
 		return PTR_ERR(region);
 
-	region_end = spi_nor_region_end(region);
+	region_end = region->offset + region->size;
 
 	while (len) {
 		erase = spi_nor_find_best_erase_type(map, region, addr, len);
@@ -1708,7 +1700,7 @@ static int spi_nor_init_erase_cmd_list(struct spi_nor *nor,
 
 		if (prev_erase != erase ||
 		    erase->size != cmd->size ||
-		    region->offset & SNOR_OVERLAID_REGION) {
+		    region->flags & SNOR_OVERLAID_REGION) {
 			cmd = spi_nor_init_erase_cmd(region, erase);
 			if (IS_ERR(cmd)) {
 				ret = PTR_ERR(cmd);
@@ -1727,7 +1719,7 @@ static int spi_nor_init_erase_cmd_list(struct spi_nor *nor,
 			region = spi_nor_region_next(region);
 			if (!region)
 				goto destroy_erase_cmd_list;
-			region_end = spi_nor_region_end(region);
+			region_end = region->offset + region->size;
 		}
 
 		prev_erase = erase;
@@ -2468,12 +2460,11 @@ void spi_nor_mask_erase_type(struct spi_nor_erase_type *erase)
 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 = 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->uniform_erase_type = erase_mask;
 }
 
 int spi_nor_post_bfpt_fixups(struct spi_nor *nor,
@@ -2560,7 +2551,7 @@ spi_nor_select_uniform_erase(struct spi_nor_erase_map *map)
 {
 	const struct spi_nor_erase_type *tested_erase, *erase = NULL;
 	int i;
-	u8 uniform_erase_type = map->uniform_erase_type;
+	u8 uniform_erase_type = map->uniform_region.erase_mask;
 
 	/*
 	 * Search for the biggest erase size, except for when compiled
@@ -2599,8 +2590,7 @@ spi_nor_select_uniform_erase(struct spi_nor_erase_map *map)
 		return NULL;
 
 	/* Disable all other Sector Erase commands. */
-	map->uniform_erase_type &= ~SNOR_ERASE_TYPE_MASK;
-	map->uniform_erase_type |= BIT(erase - map->erase_type);
+	map->uniform_region.erase_mask = BIT(erase - map->erase_type);
 	return erase;
 }
 

drivers/mtd/spi-nor/core.h

@@ -240,27 +240,25 @@ struct spi_nor_erase_command {
 /**
  * struct spi_nor_erase_region - Structure to describe a SPI NOR erase region
  * @offset:		the offset in the data array of erase region start.
- *			LSB bits are used as a bitmask encoding flags to
- *			determine if this region is overlaid, if this region is
- *			the last in the SPI NOR flash memory and to indicate
- *			all the supported erase commands inside this region.
- *			The erase types are sorted in ascending order with the
- *			smallest Erase Type size being at BIT(0).
  * @size:		the size of the region in bytes.
+ * @erase_mask:		bitmask to indicate all the supported erase commands
+ *			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
  */
 struct spi_nor_erase_region {
 	u64		offset;
 	u64		size;
+	u8		erase_mask;
+	u8		flags;
 };
 
 #define SNOR_ERASE_TYPE_MAX	4
-#define SNOR_ERASE_TYPE_MASK	GENMASK_ULL(SNOR_ERASE_TYPE_MAX - 1, 0)
 
-#define SNOR_LAST_REGION	BIT(4)
-#define SNOR_OVERLAID_REGION	BIT(5)
-
-#define SNOR_ERASE_FLAGS_MAX	6
-#define SNOR_ERASE_FLAGS_MASK	GENMASK_ULL(SNOR_ERASE_FLAGS_MAX - 1, 0)
+#define SNOR_LAST_REGION	BIT(0)
+#define SNOR_OVERLAID_REGION	BIT(1)
 
 /**
  * struct spi_nor_erase_map - Structure to describe the SPI NOR erase map
@@ -273,17 +271,11 @@ 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.
- * @uniform_erase_type:	bitmask encoding erase types that can erase the
- *			entire memory. This member is completed at init by
- *			uniform and non-uniform SPI NOR flash memories if they
- *			support at least one erase type that can erase the
- *			entire memory.
  */
 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];
-	u8				uniform_erase_type;
 };
 
 /**

drivers/mtd/spi-nor/debugfs.c

@@ -147,16 +147,17 @@ static int spi_nor_params_show(struct seq_file *s, void *data)
 	for (region = erase_map->regions;
 	     region;
 	     region = spi_nor_region_next(region)) {
-		u64 start = region->offset & ~SNOR_ERASE_FLAGS_MASK;
-		u64 flags = region->offset & SNOR_ERASE_FLAGS_MASK;
+		u64 start = region->offset;
 		u64 end = start + region->size - 1;
+		u8 erase_mask = region->erase_mask;
+		u8 flags = region->flags;
 
 		seq_printf(s, " %08llx-%08llx |     [%c%c%c%c] | %s\n",
 			   start, end,
-			   flags & BIT(0) ? '0' : ' ',
-			   flags & BIT(1) ? '1' : ' ',
-			   flags & BIT(2) ? '2' : ' ',
-			   flags & BIT(3) ? '3' : ' ',
+			   erase_mask & BIT(0) ? '0' : ' ',
+			   erase_mask & BIT(1) ? '1' : ' ',
+			   erase_mask & BIT(2) ? '2' : ' ',
+			   erase_mask & BIT(3) ? '3' : ' ',
 			   flags & SNOR_OVERLAID_REGION ? "overlaid" : "");
 	}
 

drivers/mtd/spi-nor/sfdp.c

@@ -389,17 +389,14 @@ static u8 spi_nor_sort_erase_mask(struct spi_nor_erase_map *map, u8 erase_mask)
 static void spi_nor_regions_sort_erase_types(struct spi_nor_erase_map *map)
 {
 	struct spi_nor_erase_region *region = map->regions;
-	u8 region_erase_mask, sorted_erase_mask;
+	u8 sorted_erase_mask;
 
 	while (region) {
-		region_erase_mask = region->offset & SNOR_ERASE_TYPE_MASK;
-
 		sorted_erase_mask = spi_nor_sort_erase_mask(map,
-							    region_erase_mask);
+							    region->erase_mask);
 
 		/* Overwrite erase mask. */
-		region->offset = (region->offset & ~SNOR_ERASE_TYPE_MASK) |
-				 sorted_erase_mask;
+		region->erase_mask = sorted_erase_mask;
 
 		region = spi_nor_region_next(region);
 	}
@@ -554,8 +551,6 @@ static int spi_nor_parse_bfpt(struct spi_nor *nor,
 	 * selecting the uniform erase.
 	 */
 	spi_nor_regions_sort_erase_types(map);
-	map->uniform_erase_type = map->uniform_region.offset &
-				  SNOR_ERASE_TYPE_MASK;
 
 	/* Stop here if not JESD216 rev A or later. */
 	if (bfpt_header->length == BFPT_DWORD_MAX_JESD216)
@@ -808,12 +803,12 @@ static const u32 *spi_nor_get_map_in_use(struct spi_nor *nor, const u32 *smpt,
 
 static void spi_nor_region_mark_end(struct spi_nor_erase_region *region)
 {
-	region->offset |= SNOR_LAST_REGION;
+	region->flags |= SNOR_LAST_REGION;
 }
 
 static void spi_nor_region_mark_overlay(struct spi_nor_erase_region *region)
 {
-	region->offset |= SNOR_OVERLAID_REGION;
+	region->flags |= SNOR_OVERLAID_REGION;
 }
 
 /**
@@ -875,9 +870,10 @@ static int spi_nor_init_non_uniform_erase_map(struct spi_nor *nor,
 	/* Populate regions. */
 	for (i = 0; i < region_count; i++) {
 		j = i + 1; /* index for the region dword */
+		region[i].offset = offset;
 		region[i].size = SMPT_MAP_REGION_SIZE(smpt[j]);
 		erase_type = SMPT_MAP_REGION_ERASE_TYPE(smpt[j]);
-		region[i].offset = offset | erase_type;
+		region[i].erase_mask = erase_type;
 
 		spi_nor_region_check_overlay(&region[i], erase, erase_type);
 
@@ -893,21 +889,21 @@ static int spi_nor_init_non_uniform_erase_map(struct spi_nor *nor,
 		 */
 		regions_erase_type |= erase_type;
 
-		offset = (region[i].offset & ~SNOR_ERASE_FLAGS_MASK) +
-			 region[i].size;
+		offset = region[i].offset + region[i].size;
 	}
 	spi_nor_region_mark_end(&region[i - 1]);
 
-	save_uniform_erase_type = map->uniform_erase_type;
-	map->uniform_erase_type = spi_nor_sort_erase_mask(map,
-							  uniform_erase_type);
+	save_uniform_erase_type = map->uniform_region.erase_mask;
+	map->uniform_region.erase_mask =
+				spi_nor_sort_erase_mask(map,
+							uniform_erase_type);
 
 	if (!regions_erase_type) {
 		/*
 		 * Roll back to the previous uniform_erase_type mask, SMPT is
 		 * broken.
 		 */
-		map->uniform_erase_type = save_uniform_erase_type;
+		map->uniform_region.erase_mask = save_uniform_erase_type;
 		return -EINVAL;
 	}