Retrieve saved info on restard with pstorage module

[ppatierno]

Hello,

I need to store some app configuration on the FLASH and I'd like to use the features of pstorage module. I don't understand the following thing ...

When the application starts, it uses the pstorage_register (after the pstorage_init of course) to register itself to the pstorage module and then uses it with load and store feature. On restart I can't read what I stored on the previous execution. How for each reboot of application the pstorage knows what's my app FLASH area with my saved info ? I can't find this information ...

Thanks. Paolo.

rgr_cfg.c rgr_cfg.h

[Susheel Nuguru]

Hi ppatierno,

I am sure this question has been asked many times here, but I will try to answer you. pstorage_register will reserve flash page(s) and the flash page number it reserves depend on the the settings in pstorage_platform.h and the sequence of pstorage_register.

For exampleyou code has something like this:

pstorage_init
.....
.....
pstorage_register two pages --> returns block_id1
......
......
pstorage_register three pages -->return block_id2

If the sequence of these two register function never changes over system reboots then they will always register the same physical flash page numbers, the block_id1 and block_id2 have same physical address mapping in this case and you can safely write and read your information over reboots.

but if pstorage_register is done depending on some state machine after reboot, and if the order changes like this after reset

pstorage_init
.....
.....
pstorage_register three pages -->return block_id2
......
......
pstorage_register two pages  --> returns block_id1

Then the block_id to physical address mapping has changed and you wont find the information you stored at the block_id you registered before this reboot.

[ppatierno]

Here in the first execution I have the opcode 2 in the callback (STORE) with right data. I wrote 0x10 0x20 0x30 0x40 just for test and read first two bytes from the p_data.

pstorage_register err_code = 0
m_storage_handle.block_id = 260096
pstorage_block_identifier_get err_code = 0
block_handle.block_id = 260096
block_handle.block_id err_code = p_handle=536885720, op_code=2, result=0, p_data
=536889984, data_len=4
p_data[0] = 16, p_data[1] = 32
260096

On restart I have the opcode 3 in the callback (LOAD) but p_data return me 0x00 for the first two bytes.

pstorage_register err_code = 0
m_storage_handle.block_id = 260096
pstorage_block_identifier_get err_code = 0
block_handle.block_id = 260096
p_handle=536889976, op_code=3, result=0, p_data=536889984, data_len=2
p_data[0] = 0, p_data[1] = 0
pstorage_load err_code = 0