Macronix Flash-Chip Block Protection Clearing 5.10er

[David Bauer]

Hi Nick,

On 12/25/21 16:49, Nick wrote:
> The flash-chip mx25l6405d that is contained in the Ubiquity Nanostation 
> M5 (XM) is not able to write to the flash with kernel 5.10. Probably, 
> caused by invalid block protection clearing. For example the logread 
> contains a lot of those messages:
> 
>      jffs2: Newly-erased block contained word 0x19852003 at offset 
> 0x00250000

Can you try to modify "spi_nor_get_sr_tb_mask" to always return 0?

Having a quick look at the code, there is no check if TB and BP3 bit 
conflict. Furthermore, the MXIC chip does not seem to have a TB bit at all.

I could imagine this either writes the wrong value to the register or 
does not unlock at all, as it interprets the range of the lock incorrectly.

Just a assumption, did not have a closer look.

Best
David

> 
> I added a patch with the help of blocktrron for the 5.4er kernel [0]. 
> This patch is not applied in the 5.10er since a lot of rewrites happened 
> upstream. However, the underlying issue is the missing 4th block 
> protection bit that was not cleared. In upstream Linux you typically set 
> SPI_NOR_HAS_LOCK | SPI_NOR_4BIT_B for that kind of flash chips in 
> drivers/mtd/spi-nor/macronix.c [1]. I added this for the mx25l6405d, but 
> it did not help. I also tried to backport the ("mtd: spi-nor: keep lock 
> bits if they are non-volatile") fix and setting 
> "CONFIG_MTD_SPI_NOR_SWP_DISABLE", but it also did not help. Did I miss 
> something?
> 
> [0] - 
> https://git.openwrt.org/?p=openwrt/openwrt.git;a=commit;h=c9e9b8c342d918cedfc4d2e1c2f7fd1fcaf0b56b 
> 
> [1] - 
> https://github.com/torvalds/linux/commit/7ea40b54e83baed17d85567cfae56175def39a55#diff-f749d5111926f3afbd8d869c577cb314fb690186ba42a2538a87e5ea7725929e 
> 
> [2] - 
> https://gist.github.com/PolynomialDivision/0c420c6bfcfd681cffa7aac9f346d262
> [3] - 
> https://github.com/PolynomialDivision/openwrt/blob/984f1c84e8d087a9fa0117d5502b8e19a2a35b98/target/linux/generic/backport-5.10/409-v5.11-mtd-spi-nor-keep-lock-bits-if-they-are-non-volatile.patch 
> 
> 
> 
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