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Diffstat (limited to 'doc/device-tree-bindings/firmware')
| -rw-r--r-- | doc/device-tree-bindings/firmware/nvidia,tegra186-bpmp.txt | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/doc/device-tree-bindings/firmware/nvidia,tegra186-bpmp.txt b/doc/device-tree-bindings/firmware/nvidia,tegra186-bpmp.txt new file mode 100644 index 0000000000..447252e882 --- /dev/null +++ b/doc/device-tree-bindings/firmware/nvidia,tegra186-bpmp.txt @@ -0,0 +1,104 @@ +NVIDIA Tegra Boot and Power Management Processor (BPMP) + +The BPMP is a specific processor in Tegra chip, which is designed for +booting process handling and offloading the power management, clock +management, and reset control tasks from the CPU. The binding document +defines the resources that would be used by the BPMP firmware driver, +which can create the interprocessor communication (IPC) between the CPU +and BPMP. + +Required properties: +- name : Should be bpmp +- compatible + Array of strings + One of: + - "nvidia,tegra186-bpmp" +- mboxes : The phandle of mailbox controller and the mailbox specifier. +- shmem : List of the phandle of the TX and RX shared memory area that + the IPC between CPU and BPMP is based on. +- #clock-cells : Should be 1. +- #power-domain-cells : Should be 1. +- #reset-cells : Should be 1. + +This node is a mailbox consumer. See the following files for details of +the mailbox subsystem, and the specifiers implemented by the relevant +provider(s): + +- .../mailbox/mailbox.txt +- .../mailbox/nvidia,tegra186-hsp.txt + +This node is a clock, power domain, and reset provider. See the following +files for general documentation of those features, and the specifiers +implemented by this node: + +- .../clock/clock-bindings.txt +- <dt-bindings/clock/tegra186-clock.h> +- ../power/power_domain.txt +- <dt-bindings/power/tegra186-powergate.h> +- .../reset/reset.txt +- <dt-bindings/reset/tegra186-reset.h> + +The BPMP implements some services which must be represented by separate nodes. +For example, it can provide access to certain I2C controllers, and the I2C +bindings represent each I2C controller as a device tree node. Such nodes should +be nested directly inside the main BPMP node. + +Software can determine whether a child node of the BPMP node represents a device +by checking for a compatible property. Any node with a compatible property +represents a device that can be instantiated. Nodes without a compatible +property may be used to provide configuration information regarding the BPMP +itself, although no such configuration nodes are currently defined by this +binding. + +The BPMP firmware defines no single global name-/numbering-space for such +services. Put another way, the numbering scheme for I2C buses is distinct from +the numbering scheme for any other service the BPMP may provide (e.g. a future +hypothetical SPI bus service). As such, child device nodes will have no reg +property, and the BPMP node will have no #address-cells or #size-cells property. + +The shared memory bindings for BPMP +----------------------------------- + +The shared memory area for the IPC TX and RX between CPU and BPMP are +predefined and work on top of sysram, which is an SRAM inside the chip. + +See ".../sram/sram.txt" for the bindings. + +Example: + +hsp_top0: hsp@03c00000 { + ... + #mbox-cells = <2>; +}; + +sysram@30000000 { + compatible = "nvidia,tegra186-sysram", "mmio-sram"; + reg = <0x0 0x30000000 0x0 0x50000>; + #address-cells = <2>; + #size-cells = <2>; + ranges = <0 0x0 0x0 0x30000000 0x0 0x50000>; + + cpu_bpmp_tx: bpmp_shmem@4e000 { + compatible = "nvidia,tegra186-bpmp-shmem"; + reg = <0x0 0x4e000 0x0 0x1000>; + }; + + cpu_bpmp_rx: bpmp_shmem@4f000 { + compatible = "nvidia,tegra186-bpmp-shmem"; + reg = <0x0 0x4f000 0x0 0x1000>; + }; +}; + +bpmp { + compatible = "nvidia,tegra186-bpmp"; + mboxes = <&hsp_top0 HSP_MBOX_TYPE_DB HSP_DB_MASTER_BPMP>; + shmem = <&cpu_bpmp_tx &cpu_bpmp_rx>; + #clock-cells = <1>; + #power-domain-cells = <1>; + #reset-cells = <1>; + + i2c { + compatible = "..."; + ... + }; +}; |