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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:
+ $nodename:
+ pattern: "^sram(@.*)?"
+
+ compatible:
+ contains:
+ enum:
+ - mmio-sram
+ - atmel,sama5d2-securam
+ - rockchip,rk3288-pmu-sram
+
+ reg:
+ maxItems: 1
+
+ clocks:
+ description:
+ A list of phandle and clock specifier pair that controls the single
+ SRAM clock.
+
+ "#address-cells":
+ const: 1
+
+ "#size-cells":
+ const: 1
+
+ ranges:
+ description:
+ Should translate from local addresses within the sram to bus addresses.
+
+ no-memory-wc:
+ description:
+ The flag indicating, that SRAM memory region has not to be remapped
+ as write combining. WC is used by default.
+ type: boolean
+
+patternProperties:
+ "^([a-z]*-)?sram(-section)?@[a-f0-9]+$":
+ 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>
+ contains:
+ enum:
+ - allwinner,sun4i-a10-sram-a3-a4
+ - allwinner,sun4i-a10-sram-c1
+ - allwinner,sun4i-a10-sram-d
+ - allwinner,sun9i-a80-smp-sram
+ - allwinner,sun50i-a64-sram-c
+ - amlogic,meson8-smp-sram
+ - amlogic,meson8b-smp-sram
+ - amlogic,meson-gxbb-scp-shmem
+ - amlogic,meson-axg-scp-shmem
+ - renesas,smp-sram
+ - rockchip,rk3066-smp-sram
+ - samsung,exynos4210-sysram
+ - samsung,exynos4210-sysram-ns
+ - socionext,milbeaut-smp-sram
+
+ 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
+
+if:
+ properties:
+ compatible:
+ contains:
+ const: rockchip,rk3288-pmu-sram
+
+else:
+ required:
+ - "#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>;
+ };
+ };
+
+ - |
+ // Amlogic's SMP-capable SoCs use part of the sram for the bringup of the cores.
+ // Once the core gets powered up it executes the code that is residing at a
+ // specific location.
+ //
+ // Therefore a reserved section sub-node has to be added to the mmio-sram
+ // declaration.
+ sram@d9000000 {
+ compatible = "mmio-sram";
+ reg = <0xd9000000 0x20000>;
+ #address-cells = <1>;
+ #size-cells = <1>;
+ ranges = <0 0xd9000000 0x20000>;
+
+ smp-sram@1ff80 {
+ compatible = "amlogic,meson8b-smp-sram";
+ reg = <0x1ff80 0x8>;
+ };
+ };
+
+ - |
+ sram@e63c0000 {
+ compatible = "mmio-sram";
+ reg = <0xe63c0000 0x1000>;
+ #address-cells = <1>;
+ #size-cells = <1>;
+ ranges = <0 0xe63c0000 0x1000>;
+
+ smp-sram@0 {
+ compatible = "renesas,smp-sram";
+ reg = <0 0x10>;
+ };
+ };
+
+ - |
+ sram@10080000 {
+ compatible = "mmio-sram";
+ reg = <0x10080000 0x10000>;
+ #address-cells = <1>;
+ #size-cells = <1>;
+ ranges;
+
+ smp-sram@10080000 {
+ compatible = "rockchip,rk3066-smp-sram";
+ reg = <0x10080000 0x50>;
+ };
+ };
+
+ - |
+ // Rockchip's rk3288 SoC uses the sram of pmu to store the function of
+ // resume from maskrom(the 1st level loader). This is a common use of
+ // the "pmu-sram" because it keeps power even in low power states
+ // in the system.
+ sram@ff720000 {
+ compatible = "rockchip,rk3288-pmu-sram", "mmio-sram";
+ reg = <0xff720000 0x1000>;
+ };
+
+ - |
+ // Allwinner's A80 SoC uses part of the secure sram for hotplugging of the
+ // primary core (cpu0). Once the core gets powered up it checks if a magic
+ // value is set at a specific location. If it is then the BROM will jump
+ // to the software entry address, instead of executing a standard boot.
+ //
+ // Also there are no "secure-only" properties. The implementation should
+ // check if this SRAM is usable first.
+ sram@20000 {
+ // 256 KiB secure SRAM at 0x20000
+ compatible = "mmio-sram";
+ reg = <0x00020000 0x40000>;
+ #address-cells = <1>;
+ #size-cells = <1>;
+ ranges = <0 0x00020000 0x40000>;
+
+ smp-sram@1000 {
+ // This is checked by BROM to determine if
+ // cpu0 should jump to SMP entry vector
+ compatible = "allwinner,sun9i-a80-smp-sram";
+ reg = <0x1000 0x8>;
+ };
+ };
+
+ - |
+ sram@0 {
+ compatible = "mmio-sram";
+ reg = <0x0 0x10000>;
+ #address-cells = <1>;
+ #size-cells = <1>;
+ ranges = <0 0x0 0x10000>;
+
+ smp-sram@f100 {
+ compatible = "socionext,milbeaut-smp-sram";
+ reg = <0xf100 0x20>;
+ };
+ };