| * 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>; |
| }; |