On Mon, 1 Jul 2024 at 12:15, Tudor Ambarus <tudor.ambarus@xxxxxxxxxx> wrote: > > > > On 7/1/24 10:46 AM, Erez wrote: > > When using mx25l12805d, we do not read SFDP. > > As it uses the no-SFDP flags. > > When using mx25l12833f hardware with mx25l12805d driver, it did not > > try to read the SFDP. > > Yet mx25l12833f does have SFDP, when I remove the no-SFDP flags, the > > driver fetch the SFDP. > > > > Secondly SFDP does not contain OTP information. > > > > mx25l12805d has two OTP regions of 128 KiB and 384 KiB (yes asymmetric). > > While mx25l12833f has two OTP regions of 512 KiB. > > > > How do we handle it? > > You would first try to parse SFDP and initialize the flash based on > SFDP. If there's no SFDP then you fallback to the flags declared at > flash declaration. Esben had a try recently, see [1]. I don't know if > there's any progress in that direction. That's great. I probably haven't seen it yet, as I used kernel 6.5 based. However the OTP is not in the SFDP. Reading the SFDP with "mx25l12805d" does improve :-) if a user wants to use the OTP, he must specify "mx25l12833f". Perhaps less likely, but yet no other solution for OTP at the moment. I would not go to a kernel config for this. > > Also, you haven't mentioned anything about the testing. Do you have the > flash? I test the code with mx25l12833f hardware, with an older version of the kernel, 6.5 I think. It is a kernel provided by Microchip with their setting, The SPI-NOR driver is vanilla. In my testing using kernel 6.5 with a Microchip based board. Before changing, the kernel driver, was using the "mx25l12805d" setting and did NOT read the SFDP. Once I added the "mx25l12833f" without any no-sfdp flags, the driver did read the SFDP. The driver can find "mx25l12833f" with a read ID, once I remove the "mx25l12805d" setting, I did test that too. Adding the new 'SPI_NOR_TRY_SFDP' is great. but does not provide proper OTP! All the testings were done using the same mx25l12833f hardware, only the settings in the driver were changed. I am no longer in contact with the company that provides me the hardware. And as this is a Microchip based hardware it is difficult to use the latest kernel. Anyhow as mx25l12805d hardware has not been sold since 2010, it is hard to get one. I do not want to change any setting of mx25l12805d without testing! Anyhow my patch is focused on the new Macronix OTP callbacks. I do not care about the "mx25l12833f" or "mx25l12805d" compatibilities or settings. If I had a different Macronix chip with a unique ID, I would gladly test it. I only add them as the kernel rule is that new functions must be used and tested with real hardware. Erez > > [1] > https://lore.kernel.org/linux-mtd/20240603-macronix-mx25l3205d-fixups-v2-0-ff98da26835c@xxxxxxxxxx/
