diff options
Diffstat (limited to 'common/flash.c')
| -rw-r--r-- | common/flash.c | 39 |
1 files changed, 33 insertions, 6 deletions
diff --git a/common/flash.c b/common/flash.c index 3d2802f118..b91bfe3c62 100644 --- a/common/flash.c +++ b/common/flash.c @@ -811,6 +811,17 @@ uint32_t flash_get_protect(void) return flags | flash_physical_get_protect_flags(); } +/* + * Request a flash protection flags change for |mask| flash protect flags + * to |flags| state. + * + * Order of flag processing: + * 1. Clear/Set RO_AT_BOOT + Clear *_AT_BOOT flags + Commit *_AT_BOOT flags. + * 2. Return if RO_AT_BOOT and HW-WP are not asserted. + * 3. Set remaining *_AT_BOOT flags + Commit *_AT_BOOT flags. + * 4. Commit RO_NOW. + * 5. Commit ALL_NOW. + */ int flash_set_protect(uint32_t mask, uint32_t flags) { int retval = EC_SUCCESS; @@ -842,19 +853,22 @@ int flash_set_protect(uint32_t mask, uint32_t flags) * to determine whether to clear protection for the entire flash or * leave RO protected. There are two cases that we want to keep RO * protected: - * 1. RO_AT_BOOT was already set before flash_set_protect() is + * A. RO_AT_BOOT was already set before flash_set_protect() is * called. - * 2. RO_AT_BOOT was not set, but it's requested to be set by + * B. RO_AT_BOOT was not set, but it's requested to be set by * the caller of flash_set_protect(). */ + /* 1.a - Clear RO_AT_BOOT. */ new_flags_at_boot &= ~(mask & EC_FLASH_PROTECT_RO_AT_BOOT); + /* 1.b - Set RO_AT_BOOT. */ new_flags_at_boot |= flags & EC_FLASH_PROTECT_RO_AT_BOOT; - /* Removing ALL must also remove RW/ROLLBACK */ + /* 1.c - Clear ALL_AT_BOOT. */ if ((mask & EC_FLASH_PROTECT_ALL_AT_BOOT) && !(flags & EC_FLASH_PROTECT_ALL_AT_BOOT)) { new_flags_at_boot &= ~EC_FLASH_PROTECT_ALL_AT_BOOT; + /* Must also clear RW/ROLLBACK. */ #ifdef CONFIG_FLASH_PROTECT_RW new_flags_at_boot &= ~EC_FLASH_PROTECT_RW_AT_BOOT; #endif @@ -863,23 +877,27 @@ int flash_set_protect(uint32_t mask, uint32_t flags) #endif } + /* 1.d - Clear RW_AT_BOOT. */ #ifdef CONFIG_FLASH_PROTECT_RW - /* Removing RW must also remove ALL (otherwise nothing will happen). */ if ((mask & EC_FLASH_PROTECT_RW_AT_BOOT) && !(flags & EC_FLASH_PROTECT_RW_AT_BOOT)) { new_flags_at_boot &= ~EC_FLASH_PROTECT_RW_AT_BOOT; + /* Must also clear ALL (otherwise nothing will happen). */ new_flags_at_boot &= ~EC_FLASH_PROTECT_ALL_AT_BOOT; } #endif + /* 1.e - Clear ROLLBACK_AT_BOOT. */ #ifdef CONFIG_ROLLBACK if ((mask & EC_FLASH_PROTECT_ROLLBACK_AT_BOOT) && !(flags & EC_FLASH_PROTECT_ROLLBACK_AT_BOOT)) { new_flags_at_boot &= ~EC_FLASH_PROTECT_ROLLBACK_AT_BOOT; + /* Must also remove ALL (otherwise nothing will happen). */ new_flags_at_boot &= ~EC_FLASH_PROTECT_ALL_AT_BOOT; } #endif + /* 1.f - Commit *_AT_BOOT "clears" (and RO "set" 1.b). */ if (new_flags_at_boot != old_flags_at_boot) { rv = flash_protect_at_boot(new_flags_at_boot); if (rv) @@ -887,7 +905,8 @@ int flash_set_protect(uint32_t mask, uint32_t flags) old_flags_at_boot = new_flags_at_boot; } - /* + /* 2 - Return if RO_AT_BOOT and HW-WP are not asserted. + * * All subsequent flags only work if write protect is enabled (that is, * hardware WP flag) *and* RO is protected at boot (software WP flag). */ @@ -896,36 +915,44 @@ int flash_set_protect(uint32_t mask, uint32_t flags) return retval; /* - * The case where ALL/RW/ROLLBACK_AT_BOOT is unset is already covered + * 3.a - Set ALL_AT_BOOT. + * + * The case where ALL/RW/ROLLBACK_AT_BOOT is cleared is already covered * above, so we do not need to mask it out. */ new_flags_at_boot |= flags & EC_FLASH_PROTECT_ALL_AT_BOOT; + /* 3.b - Set RW_AT_BOOT. */ #ifdef CONFIG_FLASH_PROTECT_RW new_flags_at_boot |= flags & EC_FLASH_PROTECT_RW_AT_BOOT; #endif + /* 3.c - Set ROLLBACK_AT_BOOT. */ #ifdef CONFIG_ROLLBACK new_flags_at_boot |= flags & EC_FLASH_PROTECT_ROLLBACK_AT_BOOT; #endif + /* 3.d - Commit *_AT_BOOT "sets". */ if (new_flags_at_boot != old_flags_at_boot) { rv = flash_protect_at_boot(new_flags_at_boot); if (rv) retval = rv; } + /* 4 - Commit RO_NOW. */ if (flags & EC_FLASH_PROTECT_RO_NOW) { rv = flash_physical_protect_now(0); if (rv) retval = rv; } + /* 5 - Commit ALL_NOW. */ if (flags & EC_FLASH_PROTECT_ALL_NOW) { rv = flash_physical_protect_now(1); if (rv) retval = rv; } + return retval; } |