l2cc.txt 2.1 KB

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  1. * ARM L2 Cache Controller
  2. ARM cores often have a separate level 2 cache controller. There are various
  3. implementations of the L2 cache controller with compatible programming models.
  4. The ARM L2 cache representation in the device tree should be done as follows:
  5. Required properties:
  6. - compatible : should be one of:
  7. "arm,pl310-cache"
  8. "arm,l220-cache"
  9. "arm,l210-cache"
  10. "marvell,aurora-system-cache": Marvell Controller designed to be
  11. compatible with the ARM one, with system cache mode (meaning
  12. maintenance operations on L1 are broadcasted to the L2 and L2
  13. performs the same operation).
  14. "marvell,"aurora-outer-cache: Marvell Controller designed to be
  15. compatible with the ARM one with outer cache mode.
  16. - cache-unified : Specifies the cache is a unified cache.
  17. - cache-level : Should be set to 2 for a level 2 cache.
  18. - reg : Physical base address and size of cache controller's memory mapped
  19. registers.
  20. Optional properties:
  21. - arm,data-latency : Cycles of latency for Data RAM accesses. Specifies 3 cells of
  22. read, write and setup latencies. Minimum valid values are 1. Controllers
  23. without setup latency control should use a value of 0.
  24. - arm,tag-latency : Cycles of latency for Tag RAM accesses. Specifies 3 cells of
  25. read, write and setup latencies. Controllers without setup latency control
  26. should use 0. Controllers without separate read and write Tag RAM latency
  27. values should only use the first cell.
  28. - arm,dirty-latency : Cycles of latency for Dirty RAMs. This is a single cell.
  29. - arm,filter-ranges : <start length> Starting address and length of window to
  30. filter. Addresses in the filter window are directed to the M1 port. Other
  31. addresses will go to the M0 port.
  32. - interrupts : 1 combined interrupt.
  33. - cache-id-part: cache id part number to be used if it is not present
  34. on hardware
  35. - wt-override: If present then L2 is forced to Write through mode
  36. Example:
  37. L2: cache-controller {
  38. compatible = "arm,pl310-cache";
  39. reg = <0xfff12000 0x1000>;
  40. arm,data-latency = <1 1 1>;
  41. arm,tag-latency = <2 2 2>;
  42. arm,filter-ranges = <0x80000000 0x8000000>;
  43. cache-unified;
  44. cache-level = <2>;
  45. interrupts = <45>;
  46. };