Trying to write external flash with SDK 2.2.0

[Randall]

I've been porting an app written for SDK 1.8.0 to SDK 2.2.0

In the old app I've been accessing internal flash memory with  device_get_binding( "NRF_FLASH_DRV_NAME" );  It appears that with 2.2.0 moving to the partition manager that this no longer works.  I haven't been able to figure out how to access the flash controller device.  I was hoping I could get some pointers.

 

[Amanda Hsieh]

Hi, 

device_get_binding() is indeed deprecated since v2.0.0, see this issue: https://github.com/zephyrproject-rtos/zephyr/issues/43230.

Regards,
Amanda H.

[Randall]

OK. well by using;

flashDev = DEVICE_DT_GET(DT_CHOSEN(zephyr_flash_controller));

Seems to work.  But then when I try to erase sectors in there I get a security violation.  I've tried to update my _ns .dts to add the scratch partiion;

    chosen {

        zephyr,flash = &flash0;

        zephyr,sram = &sram0_ns;

        zephyr,code-partition = &slot0_ns_partition;

        zephyr,scratch-partition = &scratch_partition;

    };

But I still get the security violation.  I'm trying ot figure out how to get this partition configured so that I can erase/write it from my non-secure app.

Thanks.

[Randall]

I have no idea what uart1 has to do with all of this.  I'm trying to write to flash.

I'm getting my flash device like this; flashDev = DEVICE_DT_GET(DT_CHOSEN(zephyr_flash_controller));

Then I'm trying to erase like this; err = flash_erase( flashDev, FLASH_BIN_OFFSET, FLASH_BIN_SIZE ))

Where FLASH_BIN_OFFSET = 0xF0000 (the start of the scratch_partition) and SIZE is the size of the partition.

When the erase code gets to the following line;     *(volatile uint32_t *)page_addr = 0xFFFFFFFF; in file nrf_nvmc.h of the inline function nrf_nvmc_page_erase_start, it immediately goes to the C_SecureFault_Handler in faults.c

 and page_addr = 0xF0000, so it's as it should be.

Randall

[Randall]

I just realized that I mistittled this ticket.  I'm not trying to write external flash, but internal flash.

I've been looking at partitions.yml to try to figure things out.  It looks like this section is now defined;

EMPTY_2:

  address: 0xf0000

  end_address: 0xf8000

  placement:

    after:

    - mcuboot_secondary

  region: flash_primary

  size: 0x8000

That used to be the scratch image in the pre 2.x SDKs.  I combined the scratch and the storage partitions in my old builds because I needed 64K of internal storage for my application.  Is there anyway to define a 64k chunk somewhere that can be setup an non_secure?

[Randall]

Contining self discovery since I'm not getting any responses, I was able to get internal flash erase/writing working by definiing a const variable in the application that is aligned on a 32k byte boundary.  The problem is, that since I'm changing the contents of the application space.  The problem with this is that it changes the app image in flash and the bootloader no longer considers it a bootable image.  So I need to either be able to figure out how to take out a segment of the app image and define it as a new, non-secure flash partition, or change the bootloader not to do the validation test.  Can you help me with either of these?

Randall

[Amanda Hsieh]

Hi, 

Try to enable CONFIG_MPU_ALLOW_FLASH_WRITE for instance.

-Amanda H.

[Randall]

This is already enabled for my application

[Randall]

Can you give me information about how to redefine the memory partitions.  the partitions.yaml file is in the build directory and I can't find the source files that are used it creating it.  I need to be able to change the parition table.

[variant]

Do you have a pm_static.yml file in your project top-level directory?

[Randall]

No.  My project is the serial_lte_modem example.  So I have everything that is in that application.  Is there any description of the use of this file that I can use to create new partitions?

[variant]

There's info on that file here.  It might be worthwhile to peruse the entire discussion of the Partition Manager

[Randall]

OK, that worked.  I copied partiions.yaml to the file pm_static.yml in my project directory.  Edited it to make a portion of my app memory be a stand along partition in the tfm non-secure space and I was able to use it as a writable flash section without screwing up the bootloader.

So we can mark this as complete.  Thanks.