Messages in this thread | | | From | <> | Subject | Re: [PATCH 2/3] mtd: spi-nor: add support for Quad Page Program to no_sfdp_flags | Date | Fri, 29 Jul 2022 07:48:13 +0000 |
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On 7/22/22 13:24, Sudip Mukherjee wrote: > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe > > Hi Tudor, >
Hi!
> On Mon, Jul 18, 2022 at 7:49 PM Sudip Mukherjee > <sudip.mukherjee@sifive.com> wrote: >> >> On Mon, Jul 18, 2022 at 6:02 PM <Tudor.Ambarus@microchip.com> wrote: >>> >>> On 7/12/22 19:38, Sudip Mukherjee wrote: >>>> [You don't often get email from sudip.mukherjee@sifive.com. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ] >>>> >>>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe >>>> >>>> Some flash chips which does not have a SFDP table can support Quad >>>> Input Page Program. Enable it in hwcaps if defined. >>>> >> >> <snip> >> >>>> diff --git a/drivers/mtd/spi-nor/core.h b/drivers/mtd/spi-nor/core.h >>>> index 58fbedc94080f..dde636bdb1a7c 100644 >>>> --- a/drivers/mtd/spi-nor/core.h >>>> +++ b/drivers/mtd/spi-nor/core.h >>>> @@ -462,6 +462,7 @@ struct spi_nor_fixups { >>>> * SPI_NOR_OCTAL_READ: flash supports Octal Read. >>>> * SPI_NOR_OCTAL_DTR_READ: flash supports octal DTR Read. >>>> * SPI_NOR_OCTAL_DTR_PP: flash supports Octal DTR Page Program. >>>> + * SPI_NOR_QUAD_PP: flash supports Quad Input Page Program. >>> >>> You don't need this flag if your flash supports the 4-byte Address >>> Instruction Table. Does you flash support it? Can you dump all the >>> SFDP tables, please? >> >> Not sure what the correct way to dump sfdp is. I did this from sysfs. > > I tried decoding this SFDP table and I think the parameters table says > it has "3-Byte only addressing". > So, I guess that means it does not support 4-byte Address Instruction > Table. And the datasheet > says it supports "Quad Input Page Program (3-byte Address)". > My existing patchset works for Quad Input Page Program, and I can send > a v2 with the previous > patch and this merged together (as you suggested) or I can try > enabling sfdp for this chip and then use
You should definitely enable SFDP and get rid of the NO_SFDP_FLAGS flags, regardless of the 1-1-4 PP outcome.
> a fixup_flags to enable "Quad Input Page Program" which I think will > be more complicated. > Which one will you suggest? >
First I'd like to understand what "much better performance" means. Would you run some speed tests please? mtd-utils should have a speedtest, otherwise you can use the in kernel mtd_speedtest module. Page programs are slow anyway, using 4 lines may not make any difference. But let's see.
About your question, it depends on how common is 1-1-4 pp. If it's common and desirable we can introduce a flash info flag.
-- Cheers, ta
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