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# SPDX-License-Identifier: GPL-2.0
%YAML 1.2
---
$id: http://devicetree.org/schemas/sram/sram.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#
title: Generic on-chip SRAM
maintainers:
- Rob Herring <robh@kernel.org>
description: |+
Simple IO memory regions to be managed by the genalloc API.
Each child of the sram node specifies a region of reserved memory. Each
child node should use a 'reg' property to specify a specific range of
reserved memory.
Following the generic-names recommended practice, node names should
reflect the purpose of the node. Unit address (@<address>) should be
appended to the name.
properties:
$nodename:
pattern: "^sram(@.*)?"
compatible:
contains:
enum:
- mmio-sram
- atmel,sama5d2-securam
reg:
maxItems: 1
clocks:
description:
A list of phandle and clock specifier pair that controls the single
SRAM clock.
"#address-cells":
const: 1
"#size-cells":
const: 1
ranges:
description:
Should translate from local addresses within the sram to bus addresses.
no-memory-wc:
description:
The flag indicating, that SRAM memory region has not to be remapped
as write combining. WC is used by default.
type: boolean
patternProperties:
"^([a-z]*-)?sram@[a-f0-9]+$":
type: object
description:
Each child of the sram node specifies a region of reserved memory.
properties:
compatible:
description:
Should contain a vendor specific string in the form
<vendor>,[<device>-]<usage>
enum:
- samsung,exynos4210-sysram
- samsung,exynos4210-sysram-ns
reg:
description:
IO mem address range, relative to the SRAM range.
maxItems: 1
pool:
description:
Indicates that the particular reserved SRAM area is addressable
and in use by another device or devices.
type: boolean
export:
description:
Indicates that the reserved SRAM area may be accessed outside
of the kernel, e.g. by bootloader or userspace.
type: boolean
protect-exec:
description: |
Same as 'pool' above but with the additional constraint that code
will be run from the region and that the memory is maintained as
read-only, executable during code execution. NOTE: This region must
be page aligned on start and end in order to properly allow
manipulation of the page attributes.
type: boolean
label:
description:
The name for the reserved partition, if omitted, the label is taken
from the node name excluding the unit address.
required:
- reg
additionalProperties: false
required:
- compatible
- reg
- "#address-cells"
- "#size-cells"
- ranges
additionalProperties: false
examples:
- |
sram@5c000000 {
compatible = "mmio-sram";
reg = <0x5c000000 0x40000>; /* 256 KiB SRAM at address 0x5c000000 */
#address-cells = <1>;
#size-cells = <1>;
ranges = <0 0x5c000000 0x40000>;
smp-sram@100 {
reg = <0x100 0x50>;
};
device-sram@1000 {
reg = <0x1000 0x1000>;
pool;
};
exported-sram@20000 {
reg = <0x20000 0x20000>;
export;
};
};
- |
// Samsung SMP-capable Exynos SoCs use part of the SYSRAM for the bringup
// of the secondary cores. Once the core gets powered up it executes the
// code that is residing at some specific location of the SYSRAM.
//
// Therefore reserved section sub-nodes have to be added to the mmio-sram
// declaration. These nodes are of two types depending upon secure or
// non-secure execution environment.
sram@2020000 {
compatible = "mmio-sram";
reg = <0x02020000 0x54000>;
#address-cells = <1>;
#size-cells = <1>;
ranges = <0 0x02020000 0x54000>;
smp-sram@0 {
compatible = "samsung,exynos4210-sysram";
reg = <0x0 0x1000>;
};
smp-sram@53000 {
compatible = "samsung,exynos4210-sysram-ns";
reg = <0x53000 0x1000>;
};
};
|
