public inbox for devicetree@vger.kernel.org
 help / color / mirror / Atom feed
From: Abhishek Tiwari <abhitiwari@linux.microsoft.com>
To: robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org,
	kees@kernel.org, tony.luck@intel.com, gpiccoli@igalia.com,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-hardening@vger.kernel.org
Cc: abhitiwari@microsoft.com,
	Abhishek Tiwari <abhitiwari@linux.microsoft.com>
Subject: [PATCH] dt-bindings: memory: Document linux,usable-memory property
Date: Thu, 13 Mar 2025 07:02:25 -0700	[thread overview]
Message-ID: <1741874545-19091-1-git-send-email-abhitiwari@linux.microsoft.com> (raw)

Add Documentation for linux,usable-memory

Signed-off-by: Abhishek Tiwari <abhitiwari@linux.microsoft.com>
---
 .../bindings/linux,usable-memory.txt          | 32 +++++++++++++++++++
 1 file changed, 32 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/linux,usable-memory.txt

diff --git a/Documentation/devicetree/bindings/linux,usable-memory.txt b/Documentation/devicetree/bindings/linux,usable-memory.txt
new file mode 100644
index 000000000000..167054d2e9a2
--- /dev/null
+++ b/Documentation/devicetree/bindings/linux,usable-memory.txt
@@ -0,0 +1,32 @@
+linux,usable-memory
+===================
+
+Description
+-----------
+The ``linux,usable-memory`` property can be used to restrict usable memory
+region. This property holds a base address and size, Memory outside of this
+range is not accessible by the kernel. This property is particularly useful
+in specialized hardware platforms where certain memory regions must be
+reserved for specific use.
+
+Common use cases include:
+- Allocating ``ramoops`` region
+- Reserving memory for hardware-specific needs
+- Fake Protecting persistent memory (PMEM)
+
+Valid memory may be sparse within the specified range.
+An example device tree configuration is shown below:
+
+.. code-block:: dts
+/ {
+	&memory {
+		linux,usable-memory = <
+			0x00000000 0x80000000 0x00000000 0x1BA00000
+			0x00000000 0xA1000000 0x00000000 0x2AC00000
+		>;
+	};
+};
+
+While this property does not represent a real hardware, the address
+and the size are expressed in #address-cells and #size-cells,
+respectively, of the root node.
-- 
2.48.1


             reply	other threads:[~2025-03-13 14:03 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-03-13 14:02 Abhishek Tiwari [this message]
2025-03-13 16:10 ` [PATCH] dt-bindings: memory: Document linux,usable-memory property Krzysztof Kozlowski
2025-03-13 18:57 ` Rob Herring
2025-07-15 10:12   ` Abhishek Tiwari

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1741874545-19091-1-git-send-email-abhitiwari@linux.microsoft.com \
    --to=abhitiwari@linux.microsoft.com \
    --cc=abhitiwari@microsoft.com \
    --cc=conor+dt@kernel.org \
    --cc=devicetree@vger.kernel.org \
    --cc=gpiccoli@igalia.com \
    --cc=kees@kernel.org \
    --cc=krzk+dt@kernel.org \
    --cc=linux-hardening@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=robh@kernel.org \
    --cc=tony.luck@intel.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox