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* ARM L2 Cache Controller
ARM cores often have a separate level 2 cache controller. There are various
implementations of the L2 cache controller with compatible programming models.
The ARM L2 cache representation in the device tree should be done as follows:
Required properties:
- compatible : should be one of:
"arm,pl310-cache"
"arm,l220-cache"
"arm,l210-cache"
"marvell,aurora-system-cache": Marvell Controller designed to be
compatible with the ARM one, with system cache mode (meaning
maintenance operations on L1 are broadcasted to the L2 and L2
performs the same operation).
"marvell,"aurora-outer-cache: Marvell Controller designed to be
compatible with the ARM one with outer cache mode.
- cache-unified : Specifies the cache is a unified cache.
- cache-level : Should be set to 2 for a level 2 cache.
- reg : Physical base address and size of cache controller's memory mapped
registers.
Optional properties:
- arm,data-latency : Cycles of latency for Data RAM accesses. Specifies 3 cells of
read, write and setup latencies. Minimum valid values are 1. Controllers
without setup latency control should use a value of 0.
- arm,tag-latency : Cycles of latency for Tag RAM accesses. Specifies 3 cells of
read, write and setup latencies. Controllers without setup latency control
should use 0. Controllers without separate read and write Tag RAM latency
values should only use the first cell.
- arm,dirty-latency : Cycles of latency for Dirty RAMs. This is a single cell.
- arm,filter-ranges : <start length> Starting address and length of window to
filter. Addresses in the filter window are directed to the M1 port. Other
addresses will go to the M0 port.
- interrupts : 1 combined interrupt.
- cache-id-part: cache id part number to be used if it is not present
on hardware
- wt-override: If present then L2 is forced to Write through mode
Example:
L2: cache-controller {
compatible = "arm,pl310-cache";
reg = <0xfff12000 0x1000>;
arm,data-latency = <1 1 1>;
arm,tag-latency = <2 2 2>;
arm,filter-ranges = <0x80000000 0x8000000>;
cache-unified;
cache-level = <2>;
interrupts = <45>;
};
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