Re: [PATCH 2/3] mtd: spi-nor: add support for Quad Page Program to no_sfdp_flags

From: <Tudor.Ambarus@microchip.com>
To: <sudip.mukherjee@sifive.com>
Cc: <p.yadav@ti.com>, <michael@walle.cc>, <miquel.raynal@bootlin.com>,
	<richard@nod.at>, <vigneshr@ti.com>, <greentime.hu@sifive.com>,
	<jude.onyenegecha@sifive.com>, <william.salmon@sifive.com>,
	<adnan.chowdhury@sifive.com>, <ben.dooks@sifive.com>,
	<linux-mtd@lists.infradead.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/3] mtd: spi-nor: add support for Quad Page Program to no_sfdp_flags
Date: Fri, 29 Jul 2022 07:35:55 +0000	[thread overview]
Message-ID: <454aadfb-2c84-5950-3144-97d65e321575@microchip.com> (raw)
In-Reply-To: <CAHyZL-fK-d+dPWG63dcFUz17uP-sG4bnSFVW_gt16snnOVTzpQ@mail.gmail.com>

On 7/18/22 21:49, Sudip Mukherjee wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> On Mon, Jul 18, 2022 at 6:02 PM <Tudor.Ambarus@microchip.com> wrote:
>>
>> On 7/12/22 19:38, Sudip Mukherjee wrote:
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>>>
>>> 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.
> 
> # cat sfdp | xxd
> 00000000: 5346 4450 0601 01ff 0006 0110 3000 00ff  SFDP........0...

We really need a decoder for this :D.
5346 4450 - sfdp signature
0601 01ff - 2nd dword, 2 parameter tables
0006 0110 - BFPT of 16 dwords
3000 00ff - parameter header, 2nd dword

> 00000010: 9d05 0103 8000 0002 ffff ffff ffff ffff  ................

9d05 0103 ID LSB = 0x9d, table with 3 dwords
8000 0002 ID MSB = 0x02 -> looks like a function specific vendor table

So the flash does not support the 4-byte Address Instruction table, we
can't retrieve the Quad PP from SFDP.

> 00000020: ffff ffff ffff ffff ffff ffff ffff ffff  ................
> 00000030: e520 f9ff ffff ff0f 44eb 086b 083b 80bb  . ......D..k.;..
> 00000040: feff ffff ffff 00ff ffff 44eb 0c20 0f52  ..........D.. .R
> 00000050: 10d8 00ff 234a c900 82d8 11ce cccd 6846  ....#J........hF
> 00000060: 7a75 7a75 f7ae d55c 4a42 2cff f030 faa9  zuzu...\JB,..0..
> 00000070: ffff ffff ffff ffff ffff ffff ffff ffff  ................
> 00000080: 5019 5016 9ff9 c064 8fef ffff            P.P....d....
> 
> 
> --
> Regards
> Sudip

-- 
Cheers,
ta
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