1# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) 2%YAML 1.2 3--- 4$id: http://devicetree.org/schemas/mailbox/arm,mhu.yaml# 5$schema: http://devicetree.org/meta-schemas/core.yaml# 6 7title: ARM MHU Mailbox Controller 8 9maintainers: 10 - Jassi Brar <jaswinder.singh@linaro.org> 11 12description: | 13 The ARM's Message-Handling-Unit (MHU) is a mailbox controller that has 3 14 independent channels/links to communicate with remote processor(s). MHU links 15 are hardwired on a platform. A link raises interrupt for any received data. 16 However, there is no specified way of knowing if the sent data has been read 17 by the remote. This driver assumes the sender polls STAT register and the 18 remote clears it after having read the data. The last channel is specified to 19 be a 'Secure' resource, hence can't be used by Linux running NS. 20 21 The MHU hardware also allows operations in doorbell mode. The MHU drives the 22 interrupt signal using a 32-bit register, with all 32-bits logically ORed 23 together. It provides a set of registers to enable software to set, clear and 24 check the status of each of the bits of this register independently. The use 25 of 32 bits per interrupt line enables software to provide more information 26 about the source of the interrupt. For example, each bit of the register can 27 be associated with a type of event that can contribute to raising the 28 interrupt. Each of the 32-bits can be used as "doorbell" to alert the remote 29 processor. 30 31# We need a select here so we don't match all nodes with 'arm,primecell' 32select: 33 properties: 34 compatible: 35 contains: 36 enum: 37 - arm,mhu 38 - arm,mhu-doorbell 39 required: 40 - compatible 41 42properties: 43 compatible: 44 oneOf: 45 - description: Data transfer mode 46 items: 47 - const: arm,mhu 48 - const: arm,primecell 49 50 - description: Doorbell mode 51 items: 52 - const: arm,mhu-doorbell 53 - const: arm,primecell 54 55 56 reg: 57 maxItems: 1 58 59 interrupts: 60 items: 61 - description: low-priority non-secure 62 - description: high-priority non-secure 63 - description: Secure 64 65 clocks: 66 maxItems: 1 67 68 clock-names: 69 items: 70 - const: apb_pclk 71 72 '#mbox-cells': 73 description: | 74 Set to 1 in data transfer mode and represents index of the channel. 75 Set to 2 in doorbell mode and represents index of the channel and doorbell 76 number. 77 enum: [ 1, 2 ] 78 79required: 80 - compatible 81 - reg 82 - interrupts 83 - '#mbox-cells' 84 85additionalProperties: false 86 87examples: 88 # Data transfer mode. 89 - | 90 soc { 91 #address-cells = <2>; 92 #size-cells = <2>; 93 94 mhuA: mailbox@2b1f0000 { 95 #mbox-cells = <1>; 96 compatible = "arm,mhu", "arm,primecell"; 97 reg = <0 0x2b1f0000 0 0x1000>; 98 interrupts = <0 36 4>, /* LP-NonSecure */ 99 <0 35 4>, /* HP-NonSecure */ 100 <0 37 4>; /* Secure */ 101 clocks = <&clock 0 2 1>; 102 clock-names = "apb_pclk"; 103 }; 104 105 mhu_client_scb: scb@2e000000 { 106 compatible = "fujitsu,mb86s70-scb-1.0"; 107 reg = <0 0x2e000000 0 0x4000>; 108 mboxes = <&mhuA 1>; /* HP-NonSecure */ 109 }; 110 }; 111 112 # Doorbell mode. 113 - | 114 soc { 115 #address-cells = <2>; 116 #size-cells = <2>; 117 118 mhuB: mailbox@2b2f0000 { 119 #mbox-cells = <2>; 120 compatible = "arm,mhu-doorbell", "arm,primecell"; 121 reg = <0 0x2b2f0000 0 0x1000>; 122 interrupts = <0 36 4>, /* LP-NonSecure */ 123 <0 35 4>, /* HP-NonSecure */ 124 <0 37 4>; /* Secure */ 125 clocks = <&clock 0 2 1>; 126 clock-names = "apb_pclk"; 127 }; 128 129 mhu_client_scpi: scpi@2f000000 { 130 compatible = "arm,scpi"; 131 reg = <0 0x2f000000 0 0x200>; 132 mboxes = <&mhuB 1 4>; /* HP-NonSecure, 5th doorbell */ 133 }; 134 }; 135