The problem of identifying the chip capacity size when using external flash on the NRF9160 chip

[pine-fish]

I am using Nordic's 9160 development kit, which is connected to an MX25R64 flash chip with a capacity of 64MB. However, whether it is through the device tree defined BFP information (default definition and BFP read from the chip are exactly the same) or by reading BFP information from the chip, the log shows 8MB, and only 8MB can be used when in use.I want to make all 64MB of the flash chip available, which should have been the case.

The BFP information defined in the device tree shows that the chip size is 64MB, but the actual display is only one eighth. I also used another 32MB flash chip, and the log shows that only 4MB of the 32MB flash chip is available

This is the log output from the serial port

Then I modified the chip size in the BFP information in the device tree to eight times 64MB, and the log showed a capacity of 64MB. When using it, everything seemed normal. However, when I used a logic analyzer to capture SPI data, I found that when the operation address was greater than 3 bytes, that is, when using addresses after 16MB, Zephyr's code treated the four byte address as a 3-byte address. For example, if I wanted to write some data on the address 0x1804000, the SPI data captured by the logic analyzer displayed the address as 0x804000, so the data was actually still stored in the area from 0 to 16MB. I think this problem may be caused by the incorrect way I modified the chip size? So actually, the problem that needs to be solved is how to make the Zephyr system correctly recognize the size of the flash chip

I use Windows 10 system and Nordic 2.6.1 version of NCS

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[JordanYates]

The MX25R64 is a 64 M-bit storage device, not a 64 M-byte storage device, see the datasheet.
64 M-bit == 8 M-byte, so everything is behaving as expected.
I can understand your confusion, the size parameter in the DTS is somewhat counter-intuitive in that the size is specified in bits, not bytes.

zephyr/dts/bindings/mtd/jedec,jesd216.yaml

Lines 25 to 27 in 2418d22

	size:
	type: int
	description: flash capacity in bits