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+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 1.
+
+The mbox specifier of the "mboxes" property in the client node should use
+the "HSP_MBOX_ID" macro which integrates the HSP type and master ID data.
+Those information can be found in the following file.
+
+- <dt-bindings/mailbox/tegra186-hsp.h>.
+
+Example:
+
+hsp_top0: hsp at 3c00000 {
+	compatible = "nvidia,tegra186-hsp";
+	reg = <0x0 0x03c00000 0x0 0xa0000>;
+	interrupts = <GIC_SPI 176 IRQ_TYPE_LEVEL_HIGH>;
+	interrupt-names = "doorbell";
+	#mbox-cells = <1>;
+};
+
+client {
+	...
+	mboxes = <&hsp_top0 HSP_MBOX_ID(DB, HSP_DB_MASTER_XXX)>;
+};

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+/*
+ * This header provides constants for binding nvidia,tegra186-hsp.
+ *
+ * The number with HSP_DB_MASTER prefix indicates the bit that is
+ * associated with a master ID in the doorbell registers.
+ */
+
+
+#ifndef _DT_BINDINGS_MAILBOX_TEGRA186_HSP_H
+#define _DT_BINDINGS_MAILBOX_TEGRA186_HSP_H
+
+#define HSP_MBOX_TYPE_DB 0x0
+#define HSP_MBOX_TYPE_SM 0x1
+#define HSP_MBOX_TYPE_SS 0x2
+#define HSP_MBOX_TYPE_AS 0x3
+
+#define HSP_DB_MASTER_CCPLEX 17
+#define HSP_DB_MASTER_BPMP 19
+
+#define HSP_MBOX_ID(type, ID) \
+		(HSP_MBOX_TYPE_##type << 16 | ID)
+
+#endif	/* _DT_BINDINGS_MAILBOX_TEGRA186_HSP_H */