bindings/reserved-memory/reserved-memory.yaml

1 # SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
3 ---
4 $id: http://devicetree.org/schemas/reserved-memory/reserved-memory.yaml#
5 $schema: http://devicetree.org/meta-schemas/core.yaml#
7 title: /reserved-memory Child Node Common
10   - devicetree-spec@vger.kernel.org
13   Reserved memory is specified as a node under the /reserved-memory node. The
14   operating system shall exclude reserved memory from normal usage one can
16   memory regions. Such memory regions are usually designed for the special
19   Each child of the reserved-memory node specifies one or more regions
20   of reserved memory. Each child node may either use a 'reg' property to
21   specify a specific range of reserved memory, or a 'size' property with
23   memory.
25   Following the generic-names recommended practice, node names should
26   reflect the purpose of the node (ie. "framebuffer" or "dma-pool").
35       - $ref: /schemas/types.yaml#/definitions/uint32
36       - $ref: /schemas/types.yaml#/definitions/uint64
38       Length based on parent's \#size-cells. Size in bytes of memory to
43       - $ref: /schemas/types.yaml#/definitions/uint32
44       - $ref: /schemas/types.yaml#/definitions/uint64
46       Length based on parent's \#size-cells. Address boundary for
49   alloc-ranges:
50     $ref: /schemas/types.yaml#/definitions/uint32-array
52       Address and Length pairs. Specifies regions of memory that are
55   iommu-addresses:
56     $ref: /schemas/types.yaml#/definitions/phandle-array
60       memory region. The phandle in the first cell refers to the device for
64       virtual address range of the region for the given device. The exact
65       format depends on the values of the "#address-cells" and "#size-cells"
69       be established for this memory region. One example where this can be
70       useful is to create an identity mapping for physical memory that the
74       If no "reg" property is specified, the "iommu-addresses" property
76       can be useful if a certain memory region should not be mapped through
79   no-map:
83       of the region as part of its standard mapping of system memory,
85       than under the control of the device driver using the region.
90       The operating system can use the memory in this region with the
91       limitation that the device driver(s) owning the region need to be
93       system can use that region to store volatile or cached data that
97   - if:
99         - no-map
104           - reusable
106   - if:
108         - reusable
113           - no-map
116   - oneOf:
117       - required:
118           - reg
120       - required:
121           - size
123   - oneOf:
125       - required:
126           - iommu-addresses
129       - required:
130           - reg
131           - iommu-addresses
136   - |
141       #address-cells = <2>;
142       #size-cells = <2>;
144       reserved-memory {
145         #address-cells = <2>;
146         #size-cells = <2>;
149         adsp_resv: reservation-adsp {
151            * Restrict IOVA mappings for ADSP buffers to the 512 MiB region
152            * from 0x40000000 - 0x5fffffff. Anything outside is reserved by
153            * the ADSP for I/O memory and private memory allocations.
155           iommu-addresses = <&adsp 0x0 0x00000000 0x00 0x40000000>,
161           iommu-addresses = <&dc0 0x0 0x90000000 0x0 0x00800000>;
166         #address-cells = <1>;
167         #size-cells = <1>;
172           memory-region = <&adsp_resv>;
177           memory-region = <&fb>;