Description
Note: This is just a template, so feel free to use/remove the unnecessary things
Description
- Type: Bug
- Priority: Major
Bug
Target
Any STM based targets with Variable internal flash sector size
Toolchain:
Any
mbed-os sha:
caeaa49 Merge pull request #5954 from ARMmbed/release-candidate
Expected behavior
FlashIAP::erase allows the user to erase multiple sectors with one call.
On STM F439 (ODIN) sector 12 starting from 0x080e0000 have size 128k, sector 13 starting from 0x08100000 have size 16k. I want to erase these two sectors so I call
FlashIAP::erase(0x080e0000, (128+16)*1024)
Actual behavior
The impelmentation cannot deal with variable sector sizes and returns -1 on alignment check.
Steps to reproduce
compile the following code:
mbed compile -m UBLOX_EVK_ODIN_W2 -t GCC_ARM and run.
#include "mbed.h"
int main()
{
FlashIAP flash;
flash.init();
size_t sec_1_start_addr = flash.get_flash_start() + 0xe0000;
size_t sec_1_size = flash.get_sector_size(sec_1_start_addr);
size_t sec_2_start_addr = sec_1_start_addr + sec_1_size;
size_t sec_2_size = flash.get_sector_size(sec_2_start_addr);
int ret = flash.erase(sec_1_start_addr, sec_1_size + sec_2_size);
printf("ret %i\r\n", ret);
ret = flash.erase(sec_1_start_addr, sec_1_size);
printf("ret %i\r\n", ret);
ret = flash.erase(sec_2_start_addr, sec_2_size);
printf("ret %i\r\n", ret);
return 0;
}
The first call fails while the subsequent calls succeed.
RCA
In FlashIAP.cpp https://github.com/ARMmbed/mbed-os/blob/master/drivers/FlashIAP.cpp#L118-L144
The algorithm tries to erase sector by sector but the alignment check is still done on the overall erase size. This will not work on variable sector sizes.
The API does not provide a way for user to get the correct erase size. User is forced to doing erasing secotor by sector at the top level thus defeating the purpose of the FlashIAP::erase API.