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stm32: Make up_progmem thread safe

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Writing to a flash sector while starting the erase of other sector
have a undefined behavior so lets add a semaphore and syncronize
access to Flash registers.

But for the semaphore to work it needs to be initialized so each
board needs call stm32_flash_initialize() on initialization, so
to avoid runtime problems it is only using semaphore and making
it thread safe if initialized, after all boards starts to call
stm32_flash_initialize() we can remove the boolean and the check.
This commit is contained in:
José Roberto de Souza 2017-03-22 10:56:37 -07:00
parent 80f56e75f9
commit 09f70c462d
2 changed files with 64 additions and 7 deletions
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1
arch/arm/src/stm32/chip/stm32_flash.h
View File

@ -392,6 +392,7 @@
* Public Functions
************************************************************************************/
void stm32_flash_initialize(void);
void stm32_flash_lock(void);
void stm32_flash_unlock(void);

70
arch/arm/src/stm32/stm32_flash.c
View File

@ -47,7 +47,9 @@
#include <nuttx/config.h>
#include <nuttx/arch.h>
#include <errno.h>
#include <stdbool.h>
#include "stm32_flash.h"
#include "stm32_rcc.h"
@ -84,10 +86,30 @@
* Private Functions
************************************************************************************/
/************************************************************************************
* Public Functions
************************************************************************************/
void stm32_flash_unlock(void)
static sem_t g_sem;
/*
* After all SMT32 boards starts calling stm32_flash_initialize() this can
* be removed.
*/
static bool g_initialized = false;
static void sem_lock(void)
{
if (g_initialized)
{
sem_wait(&g_sem);
}
}
static void sem_unlock(void)
{
if (g_initialized)
{
sem_post(&g_sem);
}
}
static void flash_unlock(void)
{
while (getreg32(STM32_FLASH_SR) & FLASH_SR_BSY)
{
@ -103,11 +125,36 @@ void stm32_flash_unlock(void)
}
}
void stm32_flash_lock(void)
static void flash_lock(void)
{
modifyreg32(STM32_FLASH_CR, 0, FLASH_CR_LOCK);
}
/************************************************************************************
* Public Functions
************************************************************************************/
void stm32_flash_initialize(void)
{
g_initialized = true;
/*
* Initialize the semaphore that manages exclusive access flash registers
*/
sem_init(&g_sem, 0, 1);
}
void stm32_flash_unlock(void)
{
sem_lock();
flash_unlock();
sem_unlock();
}
void stm32_flash_lock(void)
{
sem_lock();
flash_lock();
sem_unlock();
}
#if defined(CONFIG_STM32_STM32F10XX) || defined(CONFIG_STM32_STM32F30XX)
@ -231,6 +278,8 @@ ssize_t up_progmem_erasepage(size_t page)
return -EFAULT;
}
sem_lock();
#if !defined(CONFIG_STM32_STM32F40XX)
if (!(getreg32(STM32_RCC_CR) & RCC_CR_HSION))
{
@ -240,7 +289,7 @@ ssize_t up_progmem_erasepage(size_t page)
/* Get flash ready and begin erasing single page */
stm32_flash_unlock();
flash_unlock();
modifyreg32(STM32_FLASH_CR, 0, FLASH_CR_PAGE_ERASE);
@ -259,6 +308,7 @@ ssize_t up_progmem_erasepage(size_t page)
while (getreg32(STM32_FLASH_SR) & FLASH_SR_BSY) up_waste();
modifyreg32(STM32_FLASH_CR, FLASH_CR_PAGE_ERASE, 0);
sem_unlock();
/* Verify */
if (up_progmem_ispageerased(page) == 0)
@ -320,16 +370,19 @@ ssize_t up_progmem_write(size_t addr, const void *buf, size_t count)
return -EFAULT;
}
sem_lock();
#if !defined(CONFIG_STM32_STM32F40XX)
if (!(getreg32(STM32_RCC_CR) & RCC_CR_HSION))
{
sem_unlock();
return -EPERM;
}
#endif
/* Get flash ready and begin flashing */
stm32_flash_unlock();
flash_unlock();
modifyreg32(STM32_FLASH_CR, 0, FLASH_CR_PG);
@ -351,17 +404,20 @@ ssize_t up_progmem_write(size_t addr, const void *buf, size_t count)
if (getreg32(STM32_FLASH_SR) & FLASH_SR_WRITE_PROTECTION_ERROR)
{
modifyreg32(STM32_FLASH_CR, FLASH_CR_PG, 0);
sem_unlock();
return -EROFS;
}
if (getreg16(addr) != *hword)
{
modifyreg32(STM32_FLASH_CR, FLASH_CR_PG, 0);
sem_unlock();
return -EIO;
}
}
modifyreg32(STM32_FLASH_CR, FLASH_CR_PG, 0);
sem_unlock();
return written;
}