samples: subsys: usb: mass: Use &flash0 storage_partition for USB mass storage

[joaodullius]

Discussed in #37764

^{Originally posted by joaodullius August 18, 2021}
What would be the necessary changes for samples/subsys/usb/mass to use internal &flash0 storage_partition for the mouting the USB device partition?

From the Kconfig, it appears that it only supports RAM, NAND and SD.

Most boards (at least the nrfxxxxDKs) now have a storage_partition in the end of the &flash. I with to mount the USB there:

  storage_partition: partition@3a000 {
      label = "storage";
      reg = <0x0003a000 0x00006000>;

[jfischer-no]

From the Kconfig, it appears that it only supports RAM, NAND and SD.

No, RAM, NAND, SD are predefined strings to identify disk by ELMFAT module.

samples/subsys/usb/mass supports only NOR flash connected over QSPI on few nRF boards, see
https://github.com/zephyrproject-rtos/zephyr/blob/main/samples/subsys/usb/mass/boards/adafruit_feather_nrf52840.overlay for example.

The reason to not support internal flash in the sample is that storage partitions are usually to small and internal flash (page erase times) to slow, cumbersome configuration... (see also #33657).

You can change the sample like:

diff --git a/samples/subsys/usb/mass/Kconfig b/samples/subsys/usb/mass/Kconfig
index 5dceba3b34..c4780d865a 100644
--- a/samples/subsys/usb/mass/Kconfig
+++ b/samples/subsys/usb/mass/Kconfig
@@ -62,7 +62,7 @@ config FLASH_PAGE_LAYOUT
        default y
 
 config DISK_FLASH_START
-       default 0x0
+       default 0x73000
 
 config FLASH_LOG_LEVEL
        default 3
@@ -77,12 +77,15 @@ if NORDIC_QSPI_NOR
 config NORDIC_QSPI_NOR_FLASH_LAYOUT_PAGE_SIZE
        default 4096
 
+endif # NORDIC_QSPI_NOR
+
 config DISK_FLASH_DEV_NAME
        default "MX25R64" if "$(dt_nodelabel_enabled,mx25r64)"
        default "GD25Q16" if "$(dt_nodelabel_enabled,gd25q16)"
+       default "NRF_FLASH_DRV_NAME"
 
 config DISK_VOLUME_SIZE
-       default 0x20000
+       default 0x67000
 
 config DISK_FLASH_MAX_RW_SIZE
        default 4096
@@ -93,7 +96,6 @@ config DISK_FLASH_ERASE_ALIGNMENT
 config DISK_ERASE_BLOCK_SIZE
        default 0x1000
 
-endif # NORDIC_QSPI_NOR
 
 endif # DISK_DRIVER_FLASH

Build the sample with -DCONFIG_APP_MSC_STORAGE_FLASH_FATFS=y.

[de-nordic]

Now we have two of these: #37764

[joaodullius]

Oops, I didn´t realized that... Sorry

[de-nordic]

@joaodullius Just don't open Discussion and a bug at the same time, there is a risk that one gets converted to an other.