[PATCH v4 1/4] Add reserved-memory
Simon Glass
sjg at chromium.org
Tue Aug 29 21:18:06 CEST 2023
Bring in this file from Linux v6.5
Signed-off-by: Simon Glass <sjg at chromium.org>
---
Changes in v4:
- New patch
.../reserved-memory/reserved-memory.yaml | 181 ++++++++++++++++++
1 file changed, 181 insertions(+)
create mode 100644 dtschema/schemas/reserved-memory/reserved-memory.yaml
diff --git a/dtschema/schemas/reserved-memory/reserved-memory.yaml b/dtschema/schemas/reserved-memory/reserved-memory.yaml
new file mode 100644
index 0000000..c680e39
--- /dev/null
+++ b/dtschema/schemas/reserved-memory/reserved-memory.yaml
@@ -0,0 +1,181 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/reserved-memory/reserved-memory.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: /reserved-memory Child Node Common
+
+maintainers:
+ - devicetree-spec at vger.kernel.org
+
+description: >
+ Reserved memory is specified as a node under the /reserved-memory node. The
+ operating system shall exclude reserved memory from normal usage one can
+ create child nodes describing particular reserved (excluded from normal use)
+ memory regions. Such memory regions are usually designed for the special
+ usage by various device drivers.
+
+ Each child of the reserved-memory node specifies one or more regions
+ of reserved memory. Each child node may either use a 'reg' property to
+ specify a specific range of reserved memory, or a 'size' property with
+ optional constraints to request a dynamically allocated block of
+ memory.
+
+ Following the generic-names recommended practice, node names should
+ reflect the purpose of the node (ie. "framebuffer" or "dma-pool").
+ Unit address (@<address>) should be appended to the name if the node
+ is a static allocation.
+
+properties:
+ reg: true
+
+ size:
+ oneOf:
+ - $ref: /schemas/types.yaml#/definitions/uint32
+ - $ref: /schemas/types.yaml#/definitions/uint64
+ description: >
+ Length based on parent's \#size-cells. Size in bytes of memory to
+ reserve.
+
+ alignment:
+ oneOf:
+ - $ref: /schemas/types.yaml#/definitions/uint32
+ - $ref: /schemas/types.yaml#/definitions/uint64
+ description: >
+ Length based on parent's \#size-cells. Address boundary for
+ alignment of allocation.
+
+ alloc-ranges:
+ $ref: /schemas/types.yaml#/definitions/uint32-array
+ description: >
+ Address and Length pairs. Specifies regions of memory that are
+ acceptable to allocate from.
+
+ iommu-addresses:
+ $ref: /schemas/types.yaml#/definitions/phandle-array
+ description: >
+ A list of phandle and specifier pairs that describe static IO virtual
+ address space mappings and carveouts associated with a given reserved
+ memory region. The phandle in the first cell refers to the device for
+ which the mapping or carveout is to be created.
+
+ The specifier consists of an address/size pair and denotes the IO
+ virtual address range of the region for the given device. The exact
+ format depends on the values of the "#address-cells" and "#size-cells"
+ properties of the device referenced via the phandle.
+
+ When used in combination with a "reg" property, an IOVA mapping is to
+ be established for this memory region. One example where this can be
+ useful is to create an identity mapping for physical memory that the
+ firmware has configured some hardware to access (such as a bootsplash
+ framebuffer).
+
+ If no "reg" property is specified, the "iommu-addresses" property
+ defines carveout regions in the IOVA space for the given device. This
+ can be useful if a certain memory region should not be mapped through
+ the IOMMU.
+
+ no-map:
+ type: boolean
+ description: >
+ Indicates the operating system must not create a virtual mapping
+ of the region as part of its standard mapping of system memory,
+ nor permit speculative access to it under any circumstances other
+ than under the control of the device driver using the region.
+
+ reusable:
+ type: boolean
+ description: >
+ The operating system can use the memory in this region with the
+ limitation that the device driver(s) owning the region need to be
+ able to reclaim it back. Typically that means that the operating
+ system can use that region to store volatile or cached data that
+ can be otherwise regenerated or migrated elsewhere.
+
+allOf:
+ - if:
+ required:
+ - no-map
+
+ then:
+ not:
+ required:
+ - reusable
+
+ - if:
+ required:
+ - reusable
+
+ then:
+ not:
+ required:
+ - no-map
+
+oneOf:
+ - oneOf:
+ - required:
+ - reg
+
+ - required:
+ - size
+
+ - oneOf:
+ # IOMMU reservations
+ - required:
+ - iommu-addresses
+
+ # IOMMU mappings
+ - required:
+ - reg
+ - iommu-addresses
+
+additionalProperties: true
+
+examples:
+ - |
+ / {
+ compatible = "foo";
+ model = "foo";
+
+ #address-cells = <2>;
+ #size-cells = <2>;
+
+ reserved-memory {
+ #address-cells = <2>;
+ #size-cells = <2>;
+ ranges;
+
+ adsp_resv: reservation-adsp {
+ /*
+ * Restrict IOVA mappings for ADSP buffers to the 512 MiB region
+ * from 0x40000000 - 0x5fffffff. Anything outside is reserved by
+ * the ADSP for I/O memory and private memory allocations.
+ */
+ iommu-addresses = <&adsp 0x0 0x00000000 0x00 0x40000000>,
+ <&adsp 0x0 0x60000000 0xff 0xa0000000>;
+ };
+
+ fb: framebuffer at 90000000 {
+ reg = <0x0 0x90000000 0x0 0x00800000>;
+ iommu-addresses = <&dc0 0x0 0x90000000 0x0 0x00800000>;
+ };
+ };
+
+ bus at 0 {
+ #address-cells = <1>;
+ #size-cells = <1>;
+ ranges = <0x0 0x0 0x0 0x40000000>;
+
+ adsp: adsp at 2990000 {
+ reg = <0x2990000 0x2000>;
+ memory-region = <&adsp_resv>;
+ };
+
+ dc0: display at 15200000 {
+ reg = <0x15200000 0x10000>;
+ memory-region = <&fb>;
+ };
+ };
+ };
+...
--
2.42.0.rc2.253.gd59a3bf2b4-goog
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