diff options
| author | Aaron Sierra <asierra@xes-inc.com> | 2014-09-25 12:20:24 -0500 |
|---|---|---|
| committer | Brian Norris <computersforpeace@gmail.com> | 2015-01-09 23:24:27 -0800 |
| commit | 6958024ad5cdd78deae4da47a8722b06317dff45 (patch) | |
| tree | 14e081920d299eab8c7fa7ece0f67aefd60c37df | |
| parent | 3fc1cf5f0af4b625adff03c610f188fa8bc89911 (diff) | |
mtd: map_rom: Support UBI on ROM
UBI needs to know the physical erase block size, even on read-only
devices, since it defines the on-device layout. Use a device-tree
provided value to support previously written UBI on read-only NOR.
UBI also needs a non-zero writebufsize, so we set it to one.
Note: This was implemented because hardware write-protected CFI
NOR cannot be probed for the physical erase block size.
Signed-off-by: Joe Schultz <jschultz@xes-inc.ccom>
Signed-off-by: Aaron Sierra <asierra@xes-inc.ccom>
[Brian: removed unneeded #ifdef, note 'optional' erase-size property]
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
| -rw-r--r-- | Documentation/devicetree/bindings/mtd/mtd-physmap.txt | 5 | ||||
| -rw-r--r-- | drivers/mtd/chips/map_rom.c | 13 |
2 files changed, 17 insertions, 1 deletions
diff --git a/Documentation/devicetree/bindings/mtd/mtd-physmap.txt b/Documentation/devicetree/bindings/mtd/mtd-physmap.txt index 6b9f680cb579..4a0a48bf4ecb 100644 --- a/Documentation/devicetree/bindings/mtd/mtd-physmap.txt +++ b/Documentation/devicetree/bindings/mtd/mtd-physmap.txt @@ -36,6 +36,11 @@ are defined: - vendor-id : Contains the flash chip's vendor id (1 byte). - device-id : Contains the flash chip's device id (1 byte). +For ROM compatible devices (and ROM fallback from cfi-flash), the following +additional (optional) property is defined: + + - erase-size : The chip's physical erase block size in bytes. + The device tree may optionally contain sub-nodes describing partitions of the address space. See partition.txt for more detail. diff --git a/drivers/mtd/chips/map_rom.c b/drivers/mtd/chips/map_rom.c index 47a43cf7e5c6..e67f73ab44c9 100644 --- a/drivers/mtd/chips/map_rom.c +++ b/drivers/mtd/chips/map_rom.c @@ -11,6 +11,7 @@ #include <linux/errno.h> #include <linux/slab.h> #include <linux/init.h> +#include <linux/of.h> #include <linux/mtd/mtd.h> #include <linux/mtd/map.h> @@ -28,6 +29,15 @@ static struct mtd_chip_driver maprom_chipdrv = { .module = THIS_MODULE }; +static unsigned int default_erasesize(struct map_info *map) +{ + const __be32 *erase_size = NULL; + + erase_size = of_get_property(map->device_node, "erase-size", NULL); + + return !erase_size ? map->size : be32_to_cpu(*erase_size); +} + static struct mtd_info *map_rom_probe(struct map_info *map) { struct mtd_info *mtd; @@ -47,8 +57,9 @@ static struct mtd_info *map_rom_probe(struct map_info *map) mtd->_sync = maprom_nop; mtd->_erase = maprom_erase; mtd->flags = MTD_CAP_ROM; - mtd->erasesize = map->size; + mtd->erasesize = default_erasesize(map); mtd->writesize = 1; + mtd->writebufsize = 1; __module_get(THIS_MODULE); return mtd; |