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authorMarek Szyprowski <m.szyprowski@samsung.com>2013-10-11 09:27:28 +0200
committerGrant Likely <grant.likely@linaro.org>2013-10-15 09:26:07 +0100
commit1931ee143b0ab72924944bc06e363d837ba05063 (patch)
tree7d0f423772dfee812a3309c45474af9fea1be22b /Documentation
parentcebf3e40b01bbf88d38dc954397414afaa280023 (diff)
downloadlinux-linaro-stable-1931ee143b0ab72924944bc06e363d837ba05063.tar.gz
Revert "drivers: of: add initialization code for dma reserved memory"
This reverts commit 9d8eab7af79cb4ce2de5de39f82c455b1f796963. There is still no consensus on the bindings for the reserved memory and various drawbacks of the proposed solution has been shown, so the best now is to revert it completely and start again from scratch later. Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Grant Likely <grant.likely@linaro.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/devicetree/bindings/memory.txt168
1 files changed, 0 insertions, 168 deletions
diff --git a/Documentation/devicetree/bindings/memory.txt b/Documentation/devicetree/bindings/memory.txt
deleted file mode 100644
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--- a/Documentation/devicetree/bindings/memory.txt
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-*** Memory binding ***
-
-The /memory node provides basic information about the address and size
-of the physical memory. This node is usually filled or updated by the
-bootloader, depending on the actual memory configuration of the given
-hardware.
-
-The memory layout is described by the following node:
-
-/ {
- #address-cells = <(n)>;
- #size-cells = <(m)>;
- memory {
- device_type = "memory";
- reg = <(baseaddr1) (size1)
- (baseaddr2) (size2)
- ...
- (baseaddrN) (sizeN)>;
- };
- ...
-};
-
-A memory node follows the typical device tree rules for "reg" property:
-n: number of cells used to store base address value
-m: number of cells used to store size value
-baseaddrX: defines a base address of the defined memory bank
-sizeX: the size of the defined memory bank
-
-
-More than one memory bank can be defined.
-
-
-*** Reserved memory regions ***
-
-In /memory/reserved-memory node 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. A good example are contiguous memory allocations or
-memory sharing with other operating system on the same hardware board.
-Those special memory regions might depend on the board configuration and
-devices used on the target system.
-
-Parameters for each memory region can be encoded into the device tree
-with the following convention:
-
-[(label):] (name) {
- compatible = "linux,contiguous-memory-region", "reserved-memory-region";
- reg = <(address) (size)>;
- (linux,default-contiguous-region);
-};
-
-compatible: one or more of:
- - "linux,contiguous-memory-region" - enables binding of this
- region to Contiguous Memory Allocator (special region for
- contiguous memory allocations, shared with movable system
- memory, Linux kernel-specific).
- - "reserved-memory-region" - compatibility is defined, given
- region is assigned for exclusive usage for by the respective
- devices.
-
-reg: standard property defining the base address and size of
- the memory region
-
-linux,default-contiguous-region: property indicating that the region
- is the default region for all contiguous memory
- allocations, Linux specific (optional)
-
-It is optional to specify the base address, so if one wants to use
-autoconfiguration of the base address, '0' can be specified as a base
-address in the 'reg' property.
-
-The /memory/reserved-memory node must contain the same #address-cells
-and #size-cells value as the root node.
-
-
-*** Device node's properties ***
-
-Once regions in the /memory/reserved-memory node have been defined, they
-may be referenced by other device nodes. Bindings that wish to reference
-memory regions should explicitly document their use of the following
-property:
-
-memory-region = <&phandle_to_defined_region>;
-
-This property indicates that the device driver should use the memory
-region pointed by the given phandle.
-
-
-*** Example ***
-
-This example defines a memory consisting of 4 memory banks. 3 contiguous
-regions are defined for Linux kernel, one default of all device drivers
-(named contig_mem, placed at 0x72000000, 64MiB), one dedicated to the
-framebuffer device (labelled display_mem, placed at 0x78000000, 8MiB)
-and one for multimedia processing (labelled multimedia_mem, placed at
-0x77000000, 64MiB). 'display_mem' region is then assigned to fb@12300000
-device for DMA memory allocations (Linux kernel drivers will use CMA is
-available or dma-exclusive usage otherwise). 'multimedia_mem' is
-assigned to scaler@12500000 and codec@12600000 devices for contiguous
-memory allocations when CMA driver is enabled.
-
-The reason for creating a separate region for framebuffer device is to
-match the framebuffer base address to the one configured by bootloader,
-so once Linux kernel drivers starts no glitches on the displayed boot
-logo appears. Scaller and codec drivers should share the memory
-allocations.
-
-/ {
- #address-cells = <1>;
- #size-cells = <1>;
-
- /* ... */
-
- memory {
- reg = <0x40000000 0x10000000
- 0x50000000 0x10000000
- 0x60000000 0x10000000
- 0x70000000 0x10000000>;
-
- reserved-memory {
- #address-cells = <1>;
- #size-cells = <1>;
-
- /*
- * global autoconfigured region for contiguous allocations
- * (used only with Contiguous Memory Allocator)
- */
- contig_region@0 {
- compatible = "linux,contiguous-memory-region";
- reg = <0x0 0x4000000>;
- linux,default-contiguous-region;
- };
-
- /*
- * special region for framebuffer
- */
- display_region: region@78000000 {
- compatible = "linux,contiguous-memory-region", "reserved-memory-region";
- reg = <0x78000000 0x800000>;
- };
-
- /*
- * special region for multimedia processing devices
- */
- multimedia_region: region@77000000 {
- compatible = "linux,contiguous-memory-region";
- reg = <0x77000000 0x4000000>;
- };
- };
- };
-
- /* ... */
-
- fb0: fb@12300000 {
- status = "okay";
- memory-region = <&display_region>;
- };
-
- scaler: scaler@12500000 {
- status = "okay";
- memory-region = <&multimedia_region>;
- };
-
- codec: codec@12600000 {
- status = "okay";
- memory-region = <&multimedia_region>;
- };
-};