diff options
| -rw-r--r-- | ports/stm32/sdram.c | 33 |
1 files changed, 28 insertions, 5 deletions
diff --git a/ports/stm32/sdram.c b/ports/stm32/sdram.c index e2b29c56e..b3c5bbeee 100644 --- a/ports/stm32/sdram.c +++ b/ports/stm32/sdram.c @@ -39,6 +39,13 @@ #define SDRAM_START_ADDRESS 0xD0000000 #endif +// Provides the MPU_REGION_SIZE_X value when passed the size of region in bytes +// "m" must be a power of 2 between 32 and 4G (2**5 and 2**32) and this formula +// computes the log2 of "m", minus 1 +#define MPU_REGION_SIZE(m) (((m) - 1) / (((m) - 1) % 255 + 1) / 255 % 255 * 8 + 7 - 86 / (((m) - 1) % 255 + 12) - 1) + +#define SDRAM_MPU_REGION_SIZE (MPU_REGION_SIZE(MICROPY_HW_SDRAM_SIZE)) + #ifdef FMC_SDRAM_BANK static void sdram_init_seq(SDRAM_HandleTypeDef @@ -244,17 +251,33 @@ static void sdram_init_seq(SDRAM_HandleTypeDef /* Disable the MPU */ HAL_MPU_Disable(); - /* Configure the MPU attributes as Write-Through for External SDRAM */ + /* Configure the MPU attributes for External SDRAM + Initially disable all access for the entire SDRAM memory space, + then enable access/caching for the size used + */ MPU_InitStruct.Enable = MPU_REGION_ENABLE; + MPU_InitStruct.Number = MPU_REGION_NUMBER4; MPU_InitStruct.BaseAddress = SDRAM_START_ADDRESS; - MPU_InitStruct.Size = MPU_REGION_SIZE_256MB; - MPU_InitStruct.AccessPermission = MPU_REGION_FULL_ACCESS; + MPU_InitStruct.Size = MPU_REGION_SIZE_512MB; + MPU_InitStruct.AccessPermission = MPU_REGION_NO_ACCESS; MPU_InitStruct.IsBufferable = MPU_ACCESS_NOT_BUFFERABLE; - MPU_InitStruct.IsCacheable = MPU_ACCESS_CACHEABLE; + MPU_InitStruct.IsCacheable = MPU_ACCESS_NOT_CACHEABLE; MPU_InitStruct.IsShareable = MPU_ACCESS_NOT_SHAREABLE; - MPU_InitStruct.Number = MPU_REGION_NUMBER0; MPU_InitStruct.TypeExtField = MPU_TEX_LEVEL0; MPU_InitStruct.SubRegionDisable = 0x00; + MPU_InitStruct.DisableExec = MPU_INSTRUCTION_ACCESS_DISABLE; + HAL_MPU_ConfigRegion(&MPU_InitStruct); + + MPU_InitStruct.Enable = MPU_REGION_ENABLE; + MPU_InitStruct.Number = MPU_REGION_NUMBER5; + MPU_InitStruct.BaseAddress = SDRAM_START_ADDRESS; + MPU_InitStruct.Size = SDRAM_MPU_REGION_SIZE; + MPU_InitStruct.AccessPermission = MPU_REGION_FULL_ACCESS; + MPU_InitStruct.IsBufferable = MPU_ACCESS_BUFFERABLE; + MPU_InitStruct.IsCacheable = MPU_ACCESS_CACHEABLE; + MPU_InitStruct.IsShareable = MPU_ACCESS_NOT_SHAREABLE; + MPU_InitStruct.TypeExtField = MPU_TEX_LEVEL1; + MPU_InitStruct.SubRegionDisable = 0x00; MPU_InitStruct.DisableExec = MPU_INSTRUCTION_ACCESS_ENABLE; HAL_MPU_ConfigRegion(&MPU_InitStruct); |