Messages in this thread | | | From | <> | Subject | Re: [PATCH v16 00/15] mtd: spi-nor: add xSPI Octal DTR support | Date | Wed, 28 Oct 2020 15:21:02 +0000 |
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On 10/28/20 2:49 PM, Pratyush Yadav wrote: > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe > > Hi Tudor, > > On 28/10/20 07:53AM, Tudor.Ambarus@microchip.com wrote: >> Hi, Pratyush, >> >> On 10/5/20 6:31 PM, Pratyush Yadav wrote: >>> Tested on Micron MT35X and S28HS flashes for Octal DTR. >> >> Do these flashes define the "Command Sequences to Change to >> Octal DDR (8D-8D-8D) mode" table? Can't we use that table >> instead of defining our own octal dtr enable functions? > > The Micron flash does not have this table. The Cypress flash does. The > problem is that one of the samples of the Cypress flash I tested on had > incorrect data in that table which meant the sequence would fail. The > newer samples of the flash have the correct data.
Can we differentiate the Cypress flashes? Do you remember what was the incorrect data?
> > I don't know how many of those faulty flashes are out there in the wild. > IMO, to be on the safe side spi_nor_cypress_octal_dtr_enable() needs to > be implemented. So from the point of view of this series there is no > need to parse the Octal DDR enable table.
Meh, we cover manufacturer's mistakes. On the long run, our aim should be to follow the SFDP standard and if a flash implements it wrong, to either fix it via a fixup hook (if the fix is minimal), or to skip the faulty table.
Regarding "Command Sequences to Change to Octal DDR (8D-8D-8D) mode" table. Have you looked over https://patchwork.ozlabs.org/project/linux-mtd/patch/1590737775-4798-4-git-send-email-masonccyang@mxic.com.tw/ ? Is there a standard way to determine the offsets of opcode, addr and data in the cmd seq?
Cheers, ta > >> I see that Mason used this table for a macronix flash: >> https://patchwork.ozlabs.org/project/linux-mtd/patch/1590737775-4798-4-git-send-email-masonccyang@mxic.com.tw/ >> https://patchwork.ozlabs.org/project/linux-mtd/patch/1590737775-4798-8-git-send-email-masonccyang@mxic.com.tw/ >> >> Cheers, >> ta > > -- > Regards, > Pratyush Yadav > Texas Instruments India >
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