Re: [PATCH v2 0/5] mtd: spi-nor: Add support for Octal 8D-8D-8D mode

From: Boris Brezillon <boris.brezillon@collabora.com>
To: masonccyang@mxic.com.tw
Cc: "Pratyush Yadav" <me@yadavpratyush.com>,
	broonie@kernel.org, juliensu@mxic.com.tw,
	linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org,
	linux-spi@vger.kernel.org, miquel.raynal@bootlin.com,
	"Pratyush Yadav" <p.yadav@ti.com>,
	richard@nod.at, tudor.ambarus@microchip.com, vigneshr@ti.com
Subject: Re: [PATCH v2 0/5] mtd: spi-nor: Add support for Octal 8D-8D-8D mode
Date: Tue, 28 Apr 2020 08:34:23 +0200	[thread overview]
Message-ID: <20200428083423.4fafd187@collabora.com> (raw)
In-Reply-To: <OF18214CA5.6A9B2B30-ON48258558.001D894C-48258558.002249E0@mxic.com.tw>

On Tue, 28 Apr 2020 14:14:31 +0800
masonccyang@mxic.com.tw wrote:

> Hi Pratyush,
> 
> > > On Tue, 21 Apr 2020 14:39:42 +0800
> > > Mason Yang <masonccyang@mxic.com.tw> wrote:
> > >   
> > > > Hello,
> > > > 
> > > > This is repost of patchset from Boris Brezillon's
> > > > [RFC,00/18] mtd: spi-nor: Proposal for 8-8-8 mode support [1].  
> > > 
> > > I only quickly went through the patches you sent and saying it's a
> > > repost of the RFC is a bit of a lie. You completely ignored the state
> > > tracking I was trying to do to avoid leaving the flash in 8D mode when
> > > suspending/resetting the board, and I think that part is crucial. If I
> > > remember correctly, we already had this discussion so I must say I'm a
> > > bit disappointed.
> > > 
> > > Can you sync with Pratyush? I think his series [1] is better in that   
> it
> > > tries to restore the flash in single-SPI mode before suspend (it's
> > > missing the shutdown case, but that can be easily added I think). Of
> > > course that'd be even better to have proper state tracking at the SPI
> > > NOR level.  
> > 
> > Hi Mason,
> > 
> > I posted a re-roll of my series here [0]. Could you please base your 
> > changes on top of it? Let me know if the series is missing something you   
> 
> > need.
> > 
> > [0]    
> https://lore.kernel.org/linux-mtd/20200424184410.8578-1-p.yadav@ti.com/
> 
> 
> Our mx25uw51245g supports BFPT DWORD-18,19 and 20 data and xSPI profile 
> 1.0,
> and it comply with BFPT DWORD-19, octal mode enable sequences by write CFG 
> Reg2 
> with instruction 0x72. Therefore, I can't apply your patches.
> 
> I quickly went through your patches but can't reply them in each your 
> patches.

Why?!! Aren't you registered to the MTD mailing list? Sorry but having
reviews outside of the original thread is far from ideal. Please find a
way to reply to the original patchset.

> 
> i.e,.
> 1) [v4,03/16] spi: spi-mem: allow specifying a command's extension
> 
> -                                u8 opcode;
> +                                u16 opcode;
> 
> big/little Endian issue, right?

There's no endianness issue since it's SPI controller responsibility to
interpret this field.

> why not just u8 ext_opcode;

Because I see the ext_ext_code comimg, and it's also more consistent
with the addr field if we use an u16 and a number of cmd cycles.

> No any impact for exist code and actually only xSPI device use extension 
> command.

And extending the opcode field to an u16 has no impact either.