Messages in this thread Patch in this message | | | From | John Thomson <> | Subject | [PATCH] mtd: spi-nor: write support for minor aligned partitions | Date | Tue, 8 Jun 2021 14:07:19 +1000 |
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Do not prevent writing to mtd partitions where a partition boundary sits on a minor erasesize boundary. This addresses a FIXME that has been present since the start of the linux git history: /* Doesn't start on a boundary of major erase size */ /* FIXME: Let it be writable if it is on a boundary of * _minor_ erase size though */
Allow a uniform erase region spi-nor device to be configured to use the non-uniform erase regions code path for an erase with: CONFIG_MTD_SPI_NOR_USE_VARIABLE_ERASE=y
On supporting hardware (SECT_4K: majority of current SPI-NOR device) provide the facility for an erase to use the least number of SPI-NOR operations, as well as access to 4K erase without requiring CONFIG_MTD_SPI_NOR_USE_4K_SECTORS
Introduce erasesize_minor to the mtd struct, the smallest erasesize supported by the device
On existing devices, this is useful where write support is wanted for data on a 4K partition, such as some u-boot-env partitions, or RouterBoot soft_config, while still netting the performance benefits of using 64K sectors
Performance: time mtd erase firmware OpenWrt 5.10 ramips MT7621 w25q128jv 0xfc0000 partition length
Without this patch MTD_SPI_NOR_USE_4K_SECTORS=y |n real 2m 11.66s |0m 50.86s user 0m 0.00s |0m 0.00s sys 1m 56.20s |0m 50.80s
With this patch MTD_SPI_NOR_USE_VARIABLE_ERASE=n|y |4K_SECTORS=y real 0m 51.68s |0m 50.85s |2m 12.89s user 0m 0.00s |0m 0.00s |0m 0.01s sys 0m 46.94s |0m 50.38s |2m 12.46s
Signed-off-by: John Thomson <git@johnthomson.fastmail.com.au> --- Have not tested on variable erase regions device.
checkpatch does not like the printk(KERN_WARNING these should be changed separately beforehand?
Changes RFC -> v1: Fix uninitialized variable smatch warning Reported-by: kernel test robot <lkp@intel.com> Reported-by: Dan Carpenter <dan.carpenter@oracle.com> --- drivers/mtd/mtdpart.c | 52 ++++++++++++++++++++++++++++--------- drivers/mtd/spi-nor/Kconfig | 10 +++++++ drivers/mtd/spi-nor/core.c | 10 +++++-- include/linux/mtd/mtd.h | 2 ++ 4 files changed, 60 insertions(+), 14 deletions(-)
diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c index 665fd9020b76..fe7626b5020e 100644 --- a/drivers/mtd/mtdpart.c +++ b/drivers/mtd/mtdpart.c @@ -38,10 +38,11 @@ static struct mtd_info *allocate_partition(struct mtd_info *parent, struct mtd_info *master = mtd_get_master(parent); int wr_alignment = (parent->flags & MTD_NO_ERASE) ? master->writesize : master->erasesize; + int wr_alignment_minor = 0; u64 parent_size = mtd_is_partition(parent) ? parent->part.size : parent->size; struct mtd_info *child; - u32 remainder; + u32 remainder, remainder_minor; char *name; u64 tmp; @@ -143,6 +144,7 @@ static struct mtd_info *allocate_partition(struct mtd_info *parent, int i, max = parent->numeraseregions; u64 end = child->part.offset + child->part.size; struct mtd_erase_region_info *regions = parent->eraseregions; + uint32_t erasesize_minor = child->erasesize; /* Find the first erase regions which is part of this * partition. */ @@ -153,15 +155,24 @@ static struct mtd_info *allocate_partition(struct mtd_info *parent, if (i > 0) i--; - /* Pick biggest erasesize */ for (; i < max && regions[i].offset < end; i++) { + /* Pick biggest erasesize */ if (child->erasesize < regions[i].erasesize) child->erasesize = regions[i].erasesize; + /* Pick smallest non-zero erasesize */ + if ((erasesize_minor > regions[i].erasesize) && (regions[i].erasesize > 0)) + erasesize_minor = regions[i].erasesize; } + + if (erasesize_minor < child->erasesize) + child->erasesize_minor = erasesize_minor; + BUG_ON(child->erasesize == 0); } else { /* Single erase size */ child->erasesize = master->erasesize; + if (master->erasesize_minor) + child->erasesize_minor = master->erasesize_minor; } /* @@ -169,26 +180,43 @@ static struct mtd_info *allocate_partition(struct mtd_info *parent, * exposes several regions with different erasesize. Adjust * wr_alignment accordingly. */ - if (!(child->flags & MTD_NO_ERASE)) + if (!(child->flags & MTD_NO_ERASE)) { wr_alignment = child->erasesize; + if (IS_ENABLED(CONFIG_MTD_SPI_NOR_USE_VARIABLE_ERASE) && child->erasesize_minor) + wr_alignment_minor = child->erasesize_minor; + } tmp = mtd_get_master_ofs(child, 0); remainder = do_div(tmp, wr_alignment); if ((child->flags & MTD_WRITEABLE) && remainder) { - /* Doesn't start on a boundary of major erase size */ - /* FIXME: Let it be writable if it is on a boundary of - * _minor_ erase size though */ - child->flags &= ~MTD_WRITEABLE; - printk(KERN_WARNING"mtd: partition \"%s\" doesn't start on an erase/write block boundary -- force read-only\n", - part->name); + if (wr_alignment_minor) { + tmp = mtd_get_master_ofs(child, 0); + remainder_minor = do_div(tmp, wr_alignment_minor); + if (remainder_minor == 0) + child->erasesize = child->erasesize_minor; + } + + if ((!wr_alignment_minor) || (wr_alignment_minor && remainder_minor != 0)) { + child->flags &= ~MTD_WRITEABLE; + printk(KERN_WARNING"mtd: partition \"%s\" doesn't start on an erase/write block boundary -- force read-only\n", + part->name); + } } tmp = mtd_get_master_ofs(child, 0) + child->part.size; remainder = do_div(tmp, wr_alignment); if ((child->flags & MTD_WRITEABLE) && remainder) { - child->flags &= ~MTD_WRITEABLE; - printk(KERN_WARNING"mtd: partition \"%s\" doesn't end on an erase/write block -- force read-only\n", - part->name); + if (wr_alignment_minor) { + tmp = mtd_get_master_ofs(child, 0) + child->part.size; + remainder_minor = do_div(tmp, wr_alignment_minor); + if (remainder_minor == 0) + child->erasesize = child->erasesize_minor; + } + if ((!wr_alignment_minor) || (wr_alignment_minor && remainder_minor != 0)) { + child->flags &= ~MTD_WRITEABLE; + printk(KERN_WARNING"mtd: partition \"%s\" doesn't end on an erase/write block -- force read-only\n", + part->name); + } } child->size = child->part.size; diff --git a/drivers/mtd/spi-nor/Kconfig b/drivers/mtd/spi-nor/Kconfig index 24cd25de2b8b..09df9f1a8127 100644 --- a/drivers/mtd/spi-nor/Kconfig +++ b/drivers/mtd/spi-nor/Kconfig @@ -10,6 +10,16 @@ menuconfig MTD_SPI_NOR if MTD_SPI_NOR +config MTD_SPI_NOR_USE_VARIABLE_ERASE + bool "Disable uniform_erase to allow use of all hardware supported erasesizes" + depends on !MTD_SPI_NOR_USE_4K_SECTORS + default n + help + Allow mixed use of all hardware supported erasesizes, + by forcing spi_nor to use the multiple eraseregions code path. + For example: A 68K erase will use one 64K erase, and one 4K erase + on supporting hardware. + config MTD_SPI_NOR_USE_4K_SECTORS bool "Use small 4096 B erase sectors" default y diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c index bd2c7717eb10..43d9b54e7edd 100644 --- a/drivers/mtd/spi-nor/core.c +++ b/drivers/mtd/spi-nor/core.c @@ -1262,6 +1262,8 @@ static u8 spi_nor_convert_3to4_erase(u8 opcode) static bool spi_nor_has_uniform_erase(const struct spi_nor *nor) { + if (IS_ENABLED(CONFIG_MTD_SPI_NOR_USE_VARIABLE_ERASE)) + return false; return !!nor->params->erase_map.uniform_erase_type; } @@ -2381,6 +2383,7 @@ static int spi_nor_select_erase(struct spi_nor *nor) { struct spi_nor_erase_map *map = &nor->params->erase_map; const struct spi_nor_erase_type *erase = NULL; + const struct spi_nor_erase_type *erase_minor = NULL; struct mtd_info *mtd = &nor->mtd; u32 wanted_size = nor->info->sector_size; int i; @@ -2413,8 +2416,9 @@ static int spi_nor_select_erase(struct spi_nor *nor) */ for (i = SNOR_ERASE_TYPE_MAX - 1; i >= 0; i--) { if (map->erase_type[i].size) { - erase = &map->erase_type[i]; - break; + if (!erase) + erase = &map->erase_type[i]; + erase_minor = &map->erase_type[i]; } } @@ -2422,6 +2426,8 @@ static int spi_nor_select_erase(struct spi_nor *nor) return -EINVAL; mtd->erasesize = erase->size; + if (erase_minor && erase_minor->size < erase->size) + mtd->erasesize_minor = erase_minor->size; return 0; } diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h index a89955f3cbc8..33eafa27da50 100644 --- a/include/linux/mtd/mtd.h +++ b/include/linux/mtd/mtd.h @@ -243,6 +243,8 @@ struct mtd_info { * information below if they desire */ uint32_t erasesize; + /* "Minor" (smallest) erase size supported by the whole device */ + uint32_t erasesize_minor; /* Minimal writable flash unit size. In case of NOR flash it is 1 (even * though individual bits can be cleared), in case of NAND flash it is * one NAND page (or half, or one-fourths of it), in case of ECC-ed NOR -- 2.31.1
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