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Wed, 20 Nov 2024 09:52:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1732096361; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=CjSe/U+nzv9GiQYKnA55TJmWIVaBLG17HklLuP9BQuo=; b=UMsqcLqizhfjcdodWKdRRxIHV/G24AKIsGNrdAAq4ZT9e/a9MVuhkV/AOZQ0kRe+iAF131 xWlc7VGm++AIHwxvSi1cFpq8y3AfypDdpXPHg+R8zytnvRnc/lXI4CndJZ+clFyZkMNUkB K4rSmJ+GW3cgI/j0F0Ziev7Q82q8O/t9yiUr50dDIellFUW7jQcHAjB3R7E1NepRa1KImD zdXTwbQ4eOAIk2e9JAty7V91bo9Bvg3JKqBs7gJs9pV6bIjkqcrbzasIiMFj3N6nPUXPjS hwLeJt9Ro2U3gRa7a/vAyOWgyPSCxvuhhqafKFS9d0uH3b3+344AeSnRRue/Ig== From: Miquel Raynal To: "Mahapatra, Amit Kumar" Cc: "tudor.ambarus@linaro.org" , "michael@walle.cc" , "broonie@kernel.org" , "pratyush@kernel.org" , "richard@nod.at" , "vigneshr@ti.com" , "robh@kernel.org" , "conor+dt@kernel.org" , "krzk+dt@kernel.org" , "Abbarapu, Venkatesh" , "linux-spi@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-mtd@lists.infradead.org" , "nicolas.ferre@microchip.com" , "alexandre.belloni@bootlin.com" , "claudiu.beznea@tuxon.dev" , "Simek, Michal" , "linux-arm-kernel@lists.infradead.org" , "alsa-devel@alsa-project.org" , "patches@opensource.cirrus.com" , "git (AMD-Xilinx)" , "amitrkcian2002@gmail.com" , "beanhuo@micron.com" Subject: Re: [RFC PATCH 1/2] dt-bindings: mtd: Add bindings for describing concatinated MTD devices In-Reply-To: (Amit Kumar Mahapatra's message of "Tue, 19 Nov 2024 17:02:33 +0000") References: <20241026075347.580858-1-amit.kumar-mahapatra@amd.com> <20241026075347.580858-2-amit.kumar-mahapatra@amd.com> <87frnoy8na.fsf@bootlin.com> User-Agent: mu4e 1.12.7; emacs 29.4 Date: Wed, 20 Nov 2024 10:52:38 +0100 Message-ID: <87sermxme1.fsf@bootlin.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-GND-Sasl: miquel.raynal@bootlin.com Message-ID-Hash: CPBJ27REAZOEVA7EXIFVAZ5LBECQVVNK X-Message-ID-Hash: CPBJ27REAZOEVA7EXIFVAZ5LBECQVVNK X-MailFrom: miquel.raynal@bootlin.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; header-match-alsa-devel.alsa-project.org-0; header-match-alsa-devel.alsa-project.org-1; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header X-Mailman-Version: 3.3.9 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: On 19/11/2024 at 17:02:33 GMT, "Mahapatra, Amit Kumar" wrote: > Hello Miquel, >=20=20 >> > This approach was suggested by Rob [1] during a discussion on Miquel's >> > initial approach [2] to extend the MTD-CONCAT driver to support >> > stacked memories. >> > Define each flash node separately with its respective partitions, and >> > add a 'concat-parts' binding to link the partitions of the two flash >> > nodes that need to be concatenated. >> > >> > flash@0 { >> > compatible =3D "jedec,spi-nor" >> > ... >> > partitions { >>=20 >> Wrong indentation here and below which makes the example hard to read. > > Sorry about that. I am redefining both the flash nodes here with proper=20 > indentation. > > flash@0 { > compatible =3D "jedec,spi-nor" > ... > partitions { > compatible =3D "fixed-partitions"; > concat-partition =3D <&flash0_partition &flash1_partition>; >=20=09=09 > flash0_partition: partition@0 { > label =3D "part0_0"; > reg =3D <0x0 0x800000>; > }; > }; > }; > > flash@1 { > compatible =3D "jedec,spi-nor" > ... > partitions { > compatible =3D "fixed-partitions"; > concat-partition =3D <&flash0_partition &flash1_partition>; >=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20=20 > flash1_partition: partition@0 { > label =3D "part0_1"; > reg =3D <0x0 0x800000>; > }; > }; > }; > >>=20 >> > compatible =3D "fixed-partitions"; >> > concat-partition =3D <&flash0_partition &flash= 1_partition>; >> > flash0_partition: partition@0 { >> > label =3D "part0_0"; >> > reg =3D <0x0 0x800000>; >> > } >> > } >> > } >> > flash@1 { >> > compatible =3D "jedec,spi-nor" >> > ... >> > partitions { >> > compatible =3D "fixed-partitions"; >> > concat-partition =3D <&flash0_partition &flash= 1_partition>; >> > flash1_partition: partition@0 { >> > label =3D "part0_1"; >> > reg =3D <0x0 0x800000>; >> > } >> > } >> > } >>=20 >> This approach has a limitation I didn't think about before: you cannot u= se anything >> else than fixed partitions as partition parser. > > Yes, that's correct=E2=80=94it won't function when partitions are defined= via the=20 > command line. In my opinion, we should start by adding support for fixed= =20 > partitions, add comments in code stating the same. If needed, we can late= r=20 > extend the support to dynamic partitions as well. New thought. What if it was a pure fixed-partition capability? That's actually what we want: defining fixed partitions through device boundaries. It automatically removes the need for further dynamic partition extensions. Thanks, Miqu=C3=A8l