Re: [PATCH] mtd: spi-nor: gigadevice: add support for gd25lq128e

From: Michael Walle <michael@walle.cc>
To: Tom Fitzhenry <tom@tom-fitzhenry.me.uk>
Cc: Tudor Ambarus <tudor.ambarus@microchip.com>,
	Pratyush Yadav <p.yadav@ti.com>,
	Miquel Raynal <miquel.raynal@bootlin.com>,
	Richard Weinberger <richard@nod.at>,
	Vignesh Raghavendra <vigneshr@ti.com>,
	Martijn Braam <martijn@brixit.nl>,
	linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mtd: spi-nor: gigadevice: add support for gd25lq128e
Date: Wed, 25 May 2022 00:30:50 +0200	[thread overview]
Message-ID: <10c2bc96821e9a907e54ef1675dc4c60@walle.cc> (raw)
In-Reply-To: <28d3925a-983a-fcb8-19af-6e6baf892d53@tom-fitzhenry.me.uk>

Am 2022-05-24 22:50, schrieb Tom Fitzhenry:
> On 23/5/22 18:03, Michael Walle wrote:
>> According to JEP106BC the vendor code 0x25 is Tristar. I'm
>> not sure what is going on here.
> 
> Nor I! The board schematic[0] reports the use of GD25LQ128EWIGR
> (vendor Gigadevices), but indeed the chip itself reports vendor
> Tristar.
> 
> I will ask the community/vendor about this discrepancy.

Yes that would be great. Could also be one of the other
25h vendors, usually the continuation code is just ignored.
I'd bet it some china SPI flash.

I don't think it is a Gigadevice because the datasheet says its ID
is c86018.

>> This flash supports SFDP, please provide an SFDP dump, see [1].
> 
> I will include this in my v2 patch. For posterity, here's the dump:
> 
> $ xxd -p /sys/bus/spi/devices/spi0.0/spi-nor/sfdp
> 53464450060101ff00060110300000ff9d05010380000002ffffffffffff
> ffffffffffffffffffffffffffffffffffffe520f9ffffffff0744eb086b
> 083b80bbfeffffffffff00ffffff44eb0c200f5210d800ff234ac90082d8
> 11c7cccd68467a757a75f7a2d55c4a422cfff030c080ffffffffffffffff
> ffffffffffffffff501950169cf9c0648fecffff
> $ md5sum /sys/bus/spi/devices/spi0.0/spi-nor/sfdp
> de4d6be54e479d60859b0ca8a0ee9216  
> /sys/bus/spi/devices/spi0.0/spi-nor/sfdp
> $ cat /sys/bus/spi/devices/spi0.0/spi-nor/jedec_id
> 257018
> $ cat /sys/bus/spi/devices/spi0.0/spi-nor/partname
> gd25lq128e
> $ cat /sys/bus/spi/devices/spi0.0/spi-nor/manufacturer
> gigadevice

Thanks.

> I have attached the parsed sfdp, according to
> https://github.com/petris/sfdp-parser
> 
>> Did you test locking?
> 
> No. The datasheet mentions Status Register locking, but I will look
> into how to adequately test this.

Or just drop the locking flags for now if you like.

>> As this flash supports SFDP, please use SNOR_ID3(0x257018)
>> and drop both the INFO() and the NO_SFDP_FLAGS(). You'll
>> need my SNOR_ID3() patches [2].
> 
> SGTM, will do.

If you don't find the vendor and don't need locking, there is
also a generic SFDP flash driver [1]. You could give it a try
and add a Tested-by there.

-michael

[1] 
https://lore.kernel.org/linux-mtd/20220513133520.3945820-1-michael@walle.cc/