Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII;
 format=flowed
Content-Transfer-Encoding: 7bit
Date:   Tue, 27 Jul 2021 09:09:53 +0200
From:   Michael Walle <michael@walle.cc>
To:     Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
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>,
        linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] mtd: spi-nor: micron-st: sync flags of mt25ql02g and
 mt25qu02g with other mt25q
In-Reply-To: <c7b6c666aef9a8a2195acabe9954a417f04b6582.1627039534.git.matthias.schiffer@ew.tq-group.com>
References: <c7b6c666aef9a8a2195acabe9954a417f04b6582.1627039534.git.matthias.schiffer@ew.tq-group.com>
User-Agent: Roundcube Webmail/1.4.11
Message-ID: <f3dbab898e9f1946129e5733095bdf3c@walle.cc>
Precedence: bulk

Am 2021-07-23 13:27, schrieb Matthias Schiffer:
> All mt25q variants have the same features.
> 
> Unlike the smaller variants, no n25q with 2G exists, so we don't need 
> to
> match on the extended ID to distinguish n25q and mt25q series for these
> models.

But why shouldn't we? What if there will be another flash with
the same first three id bytes?

> Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
> ---
>  drivers/mtd/spi-nor/micron-st.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mtd/spi-nor/micron-st.c 
> b/drivers/mtd/spi-nor/micron-st.c
> index c224e59820a1..d5baa8762c8d 100644
> --- a/drivers/mtd/spi-nor/micron-st.c
> +++ b/drivers/mtd/spi-nor/micron-st.c
> @@ -181,11 +181,11 @@ static const struct flash_info st_parts[] = {
>  			      SECT_4K | USE_FSR | SPI_NOR_QUAD_READ |
>  			      NO_CHIP_ERASE) },
>  	{ "mt25ql02g",   INFO(0x20ba22, 0, 64 * 1024, 4096,
> -			      SECT_4K | USE_FSR | SPI_NOR_QUAD_READ |
> -			      NO_CHIP_ERASE) },

This bothers me. I'm not sure how this will work. I see that
chip erase is command 0xc7, but both the new and the old flash
just supports 0xc3 (DIE ERASE). Did you test these changes?

> +			      SECT_4K | USE_FSR | SPI_NOR_DUAL_READ |
> +			      SPI_NOR_QUAD_READ | SPI_NOR_4B_OPCODES) },
>  	{ "mt25qu02g",   INFO(0x20bb22, 0, 64 * 1024, 4096,
>  			      SECT_4K | USE_FSR | SPI_NOR_DUAL_READ |
> -			      SPI_NOR_QUAD_READ | NO_CHIP_ERASE) },
> +			      SPI_NOR_QUAD_READ | SPI_NOR_4B_OPCODES) },
> 
>  	{ "m25p05",  INFO(0x202010,  0,  32 * 1024,   2, 0) },
>  	{ "m25p10",  INFO(0x202011,  0,  32 * 1024,   4, 0) },

-michael