From: Vincent Whitchurch <vincent.whitchurch@axis.com>
To: <vigneshr@ti.com>, <richard@nod.at>, <miquel.raynal@bootlin.com>,
<joern@lazybastard.org>
Cc: <kernel@axis.com>,
Vincent Whitchurch <vincent.whitchurch@axis.com>,
<linux-mtd@lists.infradead.org>, <devicetree@vger.kernel.org>,
<robh+dt@kernel.org>, <krzk+dt@kernel.org>,
<frowand.list@gmail.com>, <linux-kernel@vger.kernel.org>
Subject: [PATCH v3 0/4] mtd: phram improvements
Date: Tue, 12 Apr 2022 15:52:58 +0200 [thread overview]
Message-ID: <20220412135302.1682890-1-vincent.whitchurch@axis.com> (raw)
v3:
- Fix build error on some configs.
- Reword binding.
- Added note about alternatives in cover letter (see below)
v2:
- Add note on what "phram" means in binding.
- Use /schemas/mtd/mtd.yaml instead of relative pathUse /schemas/mtd/mtd.yaml
instead of relative path in binding.
The phram driver in the MTD subsystem can be used to allow the kernel to use an
MTD or (via mtdblock) a block device in RAM (with the contents loaded by a
bootloader for example). This series has some improvements to make it more
usable by adding device tree support and to significantly improve its
performance by using cached mappings when possible.
I use this feature to pass the squashfs rootfs to the kernel when booting from
RAM. The boot is much faster and requires less memory than initrd (which is on
top of that being deprecated), and it allows the same disk images to be used
when booting from RAM, unlike initramfs.
If there is no interest in extending the phram driver to support this, an
option is to use a new custom block driver. I have patches for that too. That
will not support MTDs of course, but it works for block devices and it is
faster and smaller than mtdblock + MTD + phram.
Cc: linux-mtd@lists.infradead.org
Cc: devicetree@vger.kernel.org
Cc: robh+dt@kernel.org
Cc: krzk+dt@kernel.org
Cc: frowand.list@gmail.com
Cc: linux-kernel@vger.kernel.org
Vincent Whitchurch (4):
mtd: core: Check devicetree alias for index
dt-bindings: reserved-memory: Support MTD/block device
mtd: phram: Allow probing via reserved-memory
mtd: phram: Allow cached mappings
.../bindings/reserved-memory/phram.yaml | 47 +++++++++++
drivers/mtd/devices/phram.c | 78 +++++++++++++++++--
drivers/mtd/mtdcore.c | 11 ++-
drivers/of/platform.c | 1 +
4 files changed, 129 insertions(+), 8 deletions(-)
create mode 100644 Documentation/devicetree/bindings/reserved-memory/phram.yaml
--
2.34.1
next reply other threads:[~2022-04-12 13:53 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-12 13:52 Vincent Whitchurch [this message]
2022-04-12 13:52 ` [PATCH v3 1/4] mtd: core: Check devicetree alias for index Vincent Whitchurch
2022-04-21 7:36 ` Miquel Raynal
2022-04-12 13:53 ` [PATCH v3 2/4] dt-bindings: reserved-memory: Support MTD/block device Vincent Whitchurch
2022-04-14 16:00 ` Rob Herring
2022-04-21 7:36 ` Miquel Raynal
2022-04-12 13:53 ` [PATCH v3 3/4] mtd: phram: Allow probing via reserved-memory Vincent Whitchurch
2022-04-14 16:02 ` Rob Herring
2022-04-21 7:36 ` Miquel Raynal
2022-04-12 13:53 ` [PATCH v3 4/4] mtd: phram: Allow cached mappings Vincent Whitchurch
2022-04-13 6:45 ` kernel test robot
2022-04-14 9:04 ` Vincent Whitchurch
2022-04-25 8:28 ` Miquel Raynal
2022-04-25 8:30 ` Miquel Raynal
2022-05-10 15:26 ` Vincent Whitchurch
2022-04-21 7:35 ` Miquel Raynal
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