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Generic on-chip SRAM
Simple IO memory regions to be managed by the genalloc API.
Required properties:
- compatible : mmio-sram or atmel,sama5d2-securam
- reg : SRAM iomem address range
Reserving sram areas:
---------------------
Each child of the sram node specifies a region of reserved memory. Each
child node should use a 'reg' property to specify a specific range of
reserved memory.
Following the generic-names recommended practice, node names should
reflect the purpose of the node. Unit address (@<address>) should be
appended to the name.
Required properties in the sram node:
- #address-cells, #size-cells : should use the same values as the root node
- ranges : standard definition, should translate from local addresses
within the sram to bus addresses
Optional properties in the sram node:
- no-memory-wc : the flag indicating, that SRAM memory region has not to
be remapped as write combining. WC is used by default.
Required properties in the area nodes:
- reg : iomem address range, relative to the SRAM range
Optional properties in the area nodes:
- compatible : standard definition, should contain a vendor specific string
in the form <vendor>,[<device>-]<usage>
- pool : indicates that the particular reserved SRAM area is addressable
and in use by another device or devices
- export : indicates that the reserved SRAM area may be accessed outside
of the kernel, e.g. by bootloader or userspace
- protect-exec : Same as 'pool' above but with the additional
constraint that code wil be run from the region and
that the memory is maintained as read-only, executable
during code execution. NOTE: This region must be page
aligned on start and end in order to properly allow
manipulation of the page attributes.
- label : the name for the reserved partition, if omitted, the label
is taken from the node name excluding the unit address.
Example:
sram: sram@5c000000 {
compatible = "mmio-sram";
reg = <0x5c000000 0x40000>; /* 256 KiB SRAM at address 0x5c000000 */
#address-cells = <1>;
#size-cells = <1>;
ranges = <0 0x5c000000 0x40000>;
smp-sram@100 {
compatible = "socvendor,smp-sram";
reg = <0x100 0x50>;
};
device-sram@1000 {
reg = <0x1000 0x1000>;
pool;
};
exported@20000 {
reg = <0x20000 0x20000>;
export;
};
};
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