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Diffstat (limited to 'target/linux/ipq806x/patches/0053-of-document-bindings-for-reserved-memory-nodes.patch')
| -rw-r--r-- | target/linux/ipq806x/patches/0053-of-document-bindings-for-reserved-memory-nodes.patch | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/target/linux/ipq806x/patches/0053-of-document-bindings-for-reserved-memory-nodes.patch b/target/linux/ipq806x/patches/0053-of-document-bindings-for-reserved-memory-nodes.patch new file mode 100644 index 0000000..b499e17 --- /dev/null +++ b/target/linux/ipq806x/patches/0053-of-document-bindings-for-reserved-memory-nodes.patch @@ -0,0 +1,164 @@ +From 060a8e3db75ef98fb296b03b8fb0cdfcbcc76c6e Mon Sep 17 00:00:00 2001 +From: Grant Likely <grant.likely@linaro.org> +Date: Fri, 28 Feb 2014 14:42:46 +0100 +Subject: [PATCH 053/182] of: document bindings for reserved-memory nodes + +Reserved memory nodes allow for the reservation of static (fixed +address) regions, or dynamically allocated regions for a specific +purpose. + +[joshc: Based on binding document proposed (in non-patch form) here: + http://lkml.kernel.org/g/20131030134702.19B57C402A0@trevor.secretlab.ca + adapted to support #memory-region-cells] +Signed-off-by: Josh Cartwright <joshc@codeaurora.org> +[mszyprow: removed #memory-region-cells property] +Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> +[grant.likely: removed residual #memory-region-cells example] +Signed-off-by: Grant Likely <grant.likely@linaro.org> +--- + .../bindings/reserved-memory/reserved-memory.txt | 133 ++++++++++++++++++++ + 1 file changed, 133 insertions(+) + create mode 100644 Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt + +diff --git a/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt +new file mode 100644 +index 0000000..3da0ebd +--- /dev/null ++++ b/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt +@@ -0,0 +1,133 @@ ++*** Reserved memory regions *** ++ ++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. ++ ++Parameters for each memory region can be encoded into the device tree ++with the following nodes: ++ ++/reserved-memory node ++--------------------- ++#address-cells, #size-cells (required) - standard definition ++ - Should use the same values as the root node ++ranges (required) - standard definition ++ - Should be empty ++ ++/reserved-memory/ child nodes ++----------------------------- ++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: ++Requires either a) or b) below. ++a) static allocation ++ reg (required) - standard definition ++b) dynamic allocation ++ size (required) - length based on parent's #size-cells ++ - Size in bytes of memory to reserve. ++ alignment (optional) - length based on parent's #size-cells ++ - Address boundary for alignment of allocation. ++ alloc-ranges (optional) - prop-encoded-array (address, length pairs). ++ - Specifies regions of memory that are ++ acceptable to allocate from. ++ ++If both reg and size are present, then the reg property takes precedence ++and size is ignored. ++ ++Additional properties: ++compatible (optional) - standard definition ++ - may contain the following strings: ++ - shared-dma-pool: This indicates a region of memory meant to be ++ used as a shared pool of DMA buffers for a set of devices. It can ++ be used by an operating system to instanciate the necessary pool ++ management subsystem if necessary. ++ - vendor specific string in the form <vendor>,[<device>-]<usage> ++no-map (optional) - empty property ++ - 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 (optional) - empty property ++ - 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. ++ ++Linux implementation note: ++- If a "linux,cma-default" property is present, then Linux will use the ++ region for the default pool of the contiguous memory allocator. ++ ++Device node references to reserved memory ++----------------------------------------- ++Regions in the /reserved-memory node may be referenced by other device ++nodes by adding a memory-region property to the device node. ++ ++memory-region (optional) - phandle, specifier pairs to children of /reserved-memory ++ ++Example ++------- ++This example defines 3 contiguous regions are defined for Linux kernel: ++one default of all device drivers (named linux,cma@72000000 and 64MiB in size), ++one dedicated to the framebuffer device (named framebuffer@78000000, 8MiB), and ++one for multimedia processing (named multimedia-memory@77000000, 64MiB). ++ ++/ { ++ #address-cells = <1>; ++ #size-cells = <1>; ++ ++ memory { ++ reg = <0x40000000 0x40000000>; ++ }; ++ ++ reserved-memory { ++ #address-cells = <1>; ++ #size-cells = <1>; ++ ranges; ++ ++ /* global autoconfigured region for contiguous allocations */ ++ linux,cma { ++ compatible = "shared-dma-pool"; ++ reusable; ++ size = <0x4000000>; ++ alignment = <0x2000>; ++ linux,cma-default; ++ }; ++ ++ display_reserved: framebuffer@78000000 { ++ reg = <0x78000000 0x800000>; ++ }; ++ ++ multimedia_reserved: multimedia@77000000 { ++ compatible = "acme,multimedia-memory"; ++ reg = <0x77000000 0x4000000>; ++ }; ++ }; ++ ++ /* ... */ ++ ++ fb0: video@12300000 { ++ memory-region = <&display_reserved>; ++ /* ... */ ++ }; ++ ++ scaler: scaler@12500000 { ++ memory-region = <&multimedia_reserved>; ++ /* ... */ ++ }; ++ ++ codec: codec@12600000 { ++ memory-region = <&multimedia_reserved>; ++ /* ... */ ++ }; ++}; +-- +1.7.10.4 + |