74 lines
2.9 KiB
Plaintext
74 lines
2.9 KiB
Plaintext
Qualcomm MSM On-Chip Memory Driver
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msm-ocmem is a driver for managing On-Chip Memory (OCMEM) in MSM SoCs.
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It is responsible for allowing various clients to allocate memory from
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OCMEM based on performance, latency and power requirements.
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Required Properties:
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- compatible: Must be "qcom,msm-ocmem"
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- reg: Four pairs of physical base addresses and region sizes
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of memory mapped registers.
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- reg-names : Register region name(s) referenced in reg above
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"ocmem_ctrl_physical" corresponds to OCMEM control registers.
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"dm_ctrl_physical" corresponds to DM control registers.
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"br_ctrl_physical" corresponds to BR control registers.
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"ocmem_physical" corresponds to address range of OCMEM memory.
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- interrupts: OCMEM core interrupt(s).
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- interrupt-names: OCMEM core interrupt name(s) reference in interrupts above
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"ocmem_irq" corresponds to OCMEM Error Interrupt.
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"dm_irq" corresponds to DM Interrupt.
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- qcom,ocmem-num-regions: The number of OCMEM hardware memory regions.
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- qcom,ocmem-num-macros: The number of OCMEM hardware memory macros.
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- qcom,resource-type: The hardware resource type of the OCMEM core.
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In addition to the information on the OCMEM core, the
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device tree contains additional information describing partitions
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of the OCMEM address space. This is used to establish regions
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of OCMEM that are used for each potential client. The partitions
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can overlap and the OCMEM driver ensures that there is no possibility
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of concurrent access from more than one client to the same address range.
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This allows the OCMEM driver to maximize the usage of OCMEM at all times.
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Each partition is represented as a sub-node of the OCMEM device.
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OCMEM partitions
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Required Properties:
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- reg : The partition's offset and size within OCMEM.
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- qcom,ocmem-part-name : The name for this partition.
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- qcom,ocmem-part-min: The minimum amount of memory reserved exclusively for
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this client.
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Optional Properties:
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- qcom,ocmem-part-tail : This parameter, if present, indicates that successive
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allocations from this partition must be allocated at
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lower offsetis.
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Example:
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qcom,ocmem@fdd00000 {
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reg = <0xfdd00000 0x2000>,
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<0xfdd02000 0x2000>,
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<0xfe039000 0x400>,
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<0xfec00000 0x180000>;
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reg-names = "ocmem_ctrl_physical", "dm_ctrl_physical", "br_ctrl_physical", "ocmem_physical";
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interrupts = <0 76 0 0 77 0>;
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interrupt-names = "ocmem_irq", "dm_irq";
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qcom,ocmem-num-regions = <0x3>;
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qcom,resource-type = <0x706d636f>
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#address-cells = <1>;
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#size-cells = <1>;
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ranges = <0x0 0xfec00000 0x180000>;
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partition@0 {
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reg = <0x0 0x100000>;
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qcom,ocmem-part-name = "graphics";
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qcom,ocmem-part-min = <0x80000>;
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};
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partition@100000 {
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reg = <0x100000 0x80000>;
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qcom,ocmem-part-name = "video";
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qcom,ocmem-part-min = <0x55000>;
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};
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};
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