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stm32l1: flash: avoid duplicate calls to unlock_pecr

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Attempts to helpfully unlock PECR when required in unlock_progmem and
unlock_option_bytes actually cause a bus error due to repeated unlocks,
as per ref manual and tedious experience.  The better tested eeprom helper
routines unlock/lock in chunks, but that's not applicable for flash
writing.

Fixes: cf5fb002f6016242fb23b81fcbe98ee022bb84e9
This commit is contained in:
Karl Palsson 2016-12-16 16:39:42 +00:00
parent f974861cba
commit 950e064885
1 changed files with 18 additions and 2 deletions
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20
lib/stm32/l1/flash.c
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@ -121,6 +121,12 @@ void flash_set_ws(uint32_t ws)
FLASH_ACR = reg32; FLASH_ACR = reg32;
} }
/**
* Unlock primary access to the flash control/erase block
* You must call this before using any of the low level routines
* yourself.
* @sa flash_unlock
*/
void flash_unlock_pecr(void) void flash_unlock_pecr(void)
{ {
FLASH_PEKEYR = FLASH_PEKEYR_PEKEY1; FLASH_PEKEYR = FLASH_PEKEYR_PEKEY1;
@ -132,9 +138,14 @@ void flash_lock_pecr(void)
FLASH_PECR |= FLASH_PECR_PELOCK; FLASH_PECR |= FLASH_PECR_PELOCK;
} }
/**
* Unlock program memory itself.
* Writes the magic sequence to unlock the program memory
* you must have already unlocked access to this register!
* @sa flash_unlock_pecr
*/
void flash_unlock_progmem(void) void flash_unlock_progmem(void)
{ {
flash_unlock_pecr();
FLASH_PRGKEYR = FLASH_PRGKEYR_PRGKEY1; FLASH_PRGKEYR = FLASH_PRGKEYR_PRGKEY1;
FLASH_PRGKEYR = FLASH_PRGKEYR_PRGKEY2; FLASH_PRGKEYR = FLASH_PRGKEYR_PRGKEY2;
} }
@ -144,9 +155,14 @@ void flash_lock_progmem(void)
FLASH_PECR |= FLASH_PECR_PRGLOCK; FLASH_PECR |= FLASH_PECR_PRGLOCK;
} }
/**
* Unlock option bytes.
* Writes the magic sequence to unlock the option bytes,
* you must have already unlocked access to this register!
* @sa flash_unlock_pecr
*/
void flash_unlock_option_bytes(void) void flash_unlock_option_bytes(void)
{ {
flash_unlock_pecr();
FLASH_OPTKEYR = FLASH_OPTKEYR_OPTKEY1; FLASH_OPTKEYR = FLASH_OPTKEYR_OPTKEY1;
FLASH_OPTKEYR = FLASH_OPTKEYR_OPTKEY2; FLASH_OPTKEYR = FLASH_OPTKEYR_OPTKEY2;
} }