Rob Herring | 8c36926 | 2011-08-03 18:12:05 +0100 | [diff] [blame^] | 1 | * ARM L2 Cache Controller |
| 2 | |
| 3 | ARM cores often have a separate level 2 cache controller. There are various |
| 4 | implementations of the L2 cache controller with compatible programming models. |
| 5 | The ARM L2 cache representation in the device tree should be done as follows: |
| 6 | |
| 7 | Required properties: |
| 8 | |
| 9 | - compatible : should be one of: |
| 10 | "arm,pl310-cache" |
| 11 | "arm,l220-cache" |
| 12 | "arm,l210-cache" |
| 13 | - cache-unified : Specifies the cache is a unified cache. |
| 14 | - cache-level : Should be set to 2 for a level 2 cache. |
| 15 | - reg : Physical base address and size of cache controller's memory mapped |
| 16 | registers. |
| 17 | |
| 18 | Optional properties: |
| 19 | |
| 20 | - arm,data-latency : Cycles of latency for Data RAM accesses. Specifies 3 cells of |
| 21 | read, write and setup latencies. Minimum valid values are 1. Controllers |
| 22 | without setup latency control should use a value of 0. |
| 23 | - arm,tag-latency : Cycles of latency for Tag RAM accesses. Specifies 3 cells of |
| 24 | read, write and setup latencies. Controllers without setup latency control |
| 25 | should use 0. Controllers without separate read and write Tag RAM latency |
| 26 | values should only use the first cell. |
| 27 | - arm,dirty-latency : Cycles of latency for Dirty RAMs. This is a single cell. |
| 28 | - arm,filter-ranges : <start length> Starting address and length of window to |
| 29 | filter. Addresses in the filter window are directed to the M1 port. Other |
| 30 | addresses will go to the M0 port. |
| 31 | |
| 32 | Example: |
| 33 | |
| 34 | L2: cache-controller { |
| 35 | compatible = "arm,pl310-cache"; |
| 36 | reg = <0xfff12000 0x1000>; |
| 37 | arm,data-latency = <1 1 1>; |
| 38 | arm,tag-latency = <2 2 2>; |
| 39 | arm,filter-latency = <0x80000000 0x8000000>; |
| 40 | cache-unified; |
| 41 | cache-level = <2>; |
| 42 | }; |