nvidia,tegra186-bpmp.txt 3.4 KB

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  1. NVIDIA Tegra Boot and Power Management Processor (BPMP)
  2. The BPMP is a specific processor in Tegra chip, which is designed for
  3. booting process handling and offloading the power management, clock
  4. management, and reset control tasks from the CPU. The binding document
  5. defines the resources that would be used by the BPMP firmware driver,
  6. which can create the interprocessor communication (IPC) between the CPU
  7. and BPMP.
  8. Required properties:
  9. - name : Should be bpmp
  10. - compatible
  11. Array of strings
  12. One of:
  13. - "nvidia,tegra186-bpmp"
  14. - mboxes : The phandle of mailbox controller and the mailbox specifier.
  15. - shmem : List of the phandle of the TX and RX shared memory area that
  16. the IPC between CPU and BPMP is based on.
  17. - #clock-cells : Should be 1.
  18. - #power-domain-cells : Should be 1.
  19. - #reset-cells : Should be 1.
  20. This node is a mailbox consumer. See the following files for details of
  21. the mailbox subsystem, and the specifiers implemented by the relevant
  22. provider(s):
  23. - .../mailbox/mailbox.txt
  24. - .../mailbox/nvidia,tegra186-hsp.txt
  25. This node is a clock, power domain, and reset provider. See the following
  26. files for general documentation of those features, and the specifiers
  27. implemented by this node:
  28. - .../clock/clock-bindings.txt
  29. - <dt-bindings/clock/tegra186-clock.h>
  30. - ../power/power_domain.txt
  31. - <dt-bindings/power/tegra186-powergate.h>
  32. - .../reset/reset.txt
  33. - <dt-bindings/reset/tegra186-reset.h>
  34. The BPMP implements some services which must be represented by separate nodes.
  35. For example, it can provide access to certain I2C controllers, and the I2C
  36. bindings represent each I2C controller as a device tree node. Such nodes should
  37. be nested directly inside the main BPMP node.
  38. Software can determine whether a child node of the BPMP node represents a device
  39. by checking for a compatible property. Any node with a compatible property
  40. represents a device that can be instantiated. Nodes without a compatible
  41. property may be used to provide configuration information regarding the BPMP
  42. itself, although no such configuration nodes are currently defined by this
  43. binding.
  44. The BPMP firmware defines no single global name-/numbering-space for such
  45. services. Put another way, the numbering scheme for I2C buses is distinct from
  46. the numbering scheme for any other service the BPMP may provide (e.g. a future
  47. hypothetical SPI bus service). As such, child device nodes will have no reg
  48. property, and the BPMP node will have no #address-cells or #size-cells property.
  49. The shared memory bindings for BPMP
  50. -----------------------------------
  51. The shared memory area for the IPC TX and RX between CPU and BPMP are
  52. predefined and work on top of sysram, which is an SRAM inside the chip.
  53. See ".../sram/sram.txt" for the bindings.
  54. Example:
  55. hsp_top0: hsp@03c00000 {
  56. ...
  57. #mbox-cells = <2>;
  58. };
  59. sysram@30000000 {
  60. compatible = "nvidia,tegra186-sysram", "mmio-sram";
  61. reg = <0x0 0x30000000 0x0 0x50000>;
  62. #address-cells = <2>;
  63. #size-cells = <2>;
  64. ranges = <0 0x0 0x0 0x30000000 0x0 0x50000>;
  65. cpu_bpmp_tx: bpmp_shmem@4e000 {
  66. compatible = "nvidia,tegra186-bpmp-shmem";
  67. reg = <0x0 0x4e000 0x0 0x1000>;
  68. };
  69. cpu_bpmp_rx: bpmp_shmem@4f000 {
  70. compatible = "nvidia,tegra186-bpmp-shmem";
  71. reg = <0x0 0x4f000 0x0 0x1000>;
  72. };
  73. };
  74. bpmp {
  75. compatible = "nvidia,tegra186-bpmp";
  76. mboxes = <&hsp_top0 HSP_MBOX_TYPE_DB HSP_DB_MASTER_BPMP>;
  77. shmem = <&cpu_bpmp_tx &cpu_bpmp_rx>;
  78. #clock-cells = <1>;
  79. #power-domain-cells = <1>;
  80. #reset-cells = <1>;
  81. i2c {
  82. compatible = "...";
  83. ...
  84. };
  85. };