NVIDIA Tegra Hardware Synchronization Primitives (HSP) The HSP modules are used for the processors to share resources and communicate together. It provides a set of hardware synchronization primitives for interprocessor communication. So the interprocessor communication (IPC) protocols can use hardware synchronization primitives, when operating between two processors not in an SMP relationship. The features that HSP supported are shared mailboxes, shared semaphores, arbitrated semaphores and doorbells. Required properties: - name : Should be hsp - compatible Array of strings. one of: - "nvidia,tegra186-hsp" - reg : Offset and length of the register set for the device. - interrupt-names Array of strings. Contains a list of names for the interrupts described by the interrupt property. May contain the following entries, in any order: - "doorbell" Users of this binding MUST look up entries in the interrupt property by name, using this interrupt-names property to do so. - interrupts Array of interrupt specifiers. Must contain one entry per entry in the interrupt-names property, in a matching order. - #mbox-cells : Should be 2. The mbox specifier of the "mboxes" property in the client node should contain two data. The first one should be the HSP type and the second one should be the ID that the client is going to use. Those information can be found in the following file. - <dt-bindings/mailbox/tegra186-hsp.h>. Example: hsp_top0: hsp@3c00000 { compatible = "nvidia,tegra186-hsp"; reg = <0x0 0x03c00000 0x0 0xa0000>; interrupts = <GIC_SPI 176 IRQ_TYPE_LEVEL_HIGH>; interrupt-names = "doorbell"; #mbox-cells = <2>; }; client { ... mboxes = <&hsp_top0 TEGRA_HSP_MBOX_TYPE_DB TEGRA_HSP_DB_MASTER_XXX>; };