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author | Nikolai Artemiev <nartemiev@google.com> | 2021-10-21 00:58:12 +1100 |
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committer | Anastasia Klimchuk <aklm@chromium.org> | 2022-03-01 04:10:12 +0000 |
commit | cff87a8488597b08c8b0ffb7037ed44f840a156b (patch) | |
tree | 19f132e23a639895d58256b251ff17657728935f /writeprotect.c | |
parent | 645e5e777a3c2ebc83e0bdb52d73355a9b5814fa (diff) | |
download | flashrom-cff87a8488597b08c8b0ffb7037ed44f840a156b.tar.gz flashrom-cff87a8488597b08c8b0ffb7037ed44f840a156b.tar.bz2 flashrom-cff87a8488597b08c8b0ffb7037ed44f840a156b.zip |
libflashrom,writeprotect: add functions for reading/writing WP configs
New functions are exposed through the libflashrom API for
reading/writing chip's WP settins: `flashrom_wp_{read,write}_cfg()`.
They read/write an opaque `struct flashrom_wp_cfg` instance, which
includes the flash protection range and status register protection mode.
This commit also adds `{read,write}_wp_bits()` helper functions that
read/write chip-specific WP configuration bits.
BUG=b:195381327,b:153800563
BRANCH=none
TEST=flashrom --wp-{enable,disable,range,list,status} at end of patch series
Change-Id: I3ad25708c3321b8fb0216c3eaf6ffc07616537ad
Signed-off-by: Nikolai Artemiev <nartemiev@google.com>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/58479
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Anastasia Klimchuk <aklm@chromium.org>
Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Diffstat (limited to 'writeprotect.c')
-rw-r--r-- | writeprotect.c | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/writeprotect.c b/writeprotect.c index cfcb13c2..20b5afcc 100644 --- a/writeprotect.c +++ b/writeprotect.c @@ -23,3 +23,191 @@ #include "libflashrom.h" #include "chipdrivers.h" #include "writeprotect.h" + +/** Read and extract a single bit from the chip's registers */ +static enum flashrom_wp_result read_bit(uint8_t *value, bool *present, struct flashctx *flash, struct reg_bit_info bit) +{ + *present = bit.reg != INVALID_REG; + if (*present) { + if (spi_read_register(flash, bit.reg, value)) + return FLASHROM_WP_ERR_READ_FAILED; + *value = (*value >> bit.bit_index) & 1; + } else { + /* Zero bit, it may be used by compare_ranges(). */ + *value = 0; + } + + return FLASHROM_WP_OK; +} + +/** Read all WP configuration bits from the chip's registers. */ +static enum flashrom_wp_result read_wp_bits(struct wp_bits *bits, struct flashctx *flash) +{ + /* + * For each WP bit that is included in the chip's register layout, read + * the register that contains it, extracts the bit's value, and assign + * it to the appropriate field in the wp_bits structure. + */ + const struct reg_bit_map *bit_map = &flash->chip->reg_bits; + bool ignored; + size_t i; + enum flashrom_wp_result ret; + + ret = read_bit(&bits->tb, &bits->tb_bit_present, flash, bit_map->tb); + if (ret != FLASHROM_WP_OK) + return ret; + + ret = read_bit(&bits->sec, &bits->sec_bit_present, flash, bit_map->sec); + if (ret != FLASHROM_WP_OK) + return ret; + + ret = read_bit(&bits->cmp, &bits->cmp_bit_present, flash, bit_map->cmp); + if (ret != FLASHROM_WP_OK) + return ret; + + ret = read_bit(&bits->srp, &bits->srp_bit_present, flash, bit_map->srp); + if (ret != FLASHROM_WP_OK) + return ret; + + ret = read_bit(&bits->srl, &bits->srl_bit_present, flash, bit_map->srl); + if (ret != FLASHROM_WP_OK) + return ret; + + for (i = 0; i < ARRAY_SIZE(bits->bp); i++) { + if (bit_map->bp[i].reg == INVALID_REG) + break; + + bits->bp_bit_count = i + 1; + ret = read_bit(&bits->bp[i], &ignored, flash, bit_map->bp[i]); + if (ret != FLASHROM_WP_OK) + return ret; + } + + return ret; +} + +/** Helper function for write_wp_bits(). */ +static void set_reg_bit( + uint8_t *reg_values, uint8_t *write_masks, + struct reg_bit_info bit, uint8_t value) +{ + if (bit.reg != INVALID_REG) { + reg_values[bit.reg] |= value << bit.bit_index; + write_masks[bit.reg] |= 1 << bit.bit_index; + } +} + +/** Write WP configuration bits to the flash's registers. */ +static enum flashrom_wp_result write_wp_bits(struct flashctx *flash, struct wp_bits bits) +{ + size_t i; + const struct reg_bit_map *reg_bits = &flash->chip->reg_bits; + + /* Convert wp_bits to register values and write masks */ + uint8_t reg_values[MAX_REGISTERS] = {0}; + uint8_t write_masks[MAX_REGISTERS] = {0}; + + for (i = 0; i < bits.bp_bit_count; i++) + set_reg_bit(reg_values, write_masks, reg_bits->bp[i], bits.bp[i]); + + set_reg_bit(reg_values, write_masks, reg_bits->tb, bits.tb); + set_reg_bit(reg_values, write_masks, reg_bits->sec, bits.sec); + set_reg_bit(reg_values, write_masks, reg_bits->cmp, bits.cmp); + set_reg_bit(reg_values, write_masks, reg_bits->srp, bits.srp); + set_reg_bit(reg_values, write_masks, reg_bits->srl, bits.srl); + + /* Write each register */ + for (enum flash_reg reg = STATUS1; reg < MAX_REGISTERS; reg++) { + if (!write_masks[reg]) + continue; + + uint8_t value; + if (spi_read_register(flash, reg, &value)) + return FLASHROM_WP_ERR_READ_FAILED; + + value = (value & ~write_masks[reg]) | (reg_values[reg] & write_masks[reg]); + + if (spi_write_register(flash, reg, value)) + return FLASHROM_WP_ERR_WRITE_FAILED; + } + + /* Verify each register */ + for (enum flash_reg reg = STATUS1; reg < MAX_REGISTERS; reg++) { + if (!write_masks[reg]) + continue; + + uint8_t value; + if (spi_read_register(flash, reg, &value)) + return FLASHROM_WP_ERR_READ_FAILED; + + uint8_t actual = value & write_masks[reg]; + uint8_t expected = reg_values[reg] & write_masks[reg]; + + if (actual != expected) + return FLASHROM_WP_ERR_VERIFY_FAILED; + } + + return FLASHROM_WP_OK; +} + +static bool chip_supported(struct flashctx *flash) +{ + return false; +} + +enum flashrom_wp_result wp_read_cfg(struct flashrom_wp_cfg *cfg, struct flashctx *flash) +{ + struct wp_bits bits; + enum flashrom_wp_result ret = FLASHROM_WP_OK; + + if (!chip_supported(flash)) + ret = FLASHROM_WP_ERR_CHIP_UNSUPPORTED; + + if (ret == FLASHROM_WP_OK) + ret = read_wp_bits(&bits, flash); + + /* TODO: implement get_wp_range() and get_wp_mode() and call them */ + /* + if (ret == FLASHROM_WP_OK) + ret = get_wp_range(&cfg->range, flash, &bits); + + if (ret == FLASHROM_WP_OK) + ret = get_wp_mode(&cfg->mode, &bits); + */ + + return ret; +} + +enum flashrom_wp_result wp_write_cfg(struct flashctx *flash, const struct flashrom_wp_cfg *cfg) +{ + struct wp_bits bits; + enum flashrom_wp_result ret = FLASHROM_WP_OK; + + if (!chip_supported(flash)) + ret = FLASHROM_WP_ERR_CHIP_UNSUPPORTED; + + if (ret == FLASHROM_WP_OK) + ret = read_wp_bits(&bits, flash); + + /* Set protection range */ + /* TODO: implement set_wp_range() and use it */ + /* + if (ret == FLASHROM_WP_OK) + ret = set_wp_range(&bits, flash, cfg->range); + if (ret == FLASHROM_WP_OK) + ret = write_wp_bits(flash, bits); + */ + + /* Set protection mode */ + /* TODO: implement set_wp_mode() and use it */ + /* + if (ret == FLASHROM_WP_OK) + ret = set_wp_mode(&bits, cfg->mode); + */ + if (ret == FLASHROM_WP_OK) + ret = write_wp_bits(flash, bits); + + return ret; +} + +/** @} */ /* end flashrom-wp */ |