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| 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 | + |
| 7 | +title: ARM MHU Mailbox Controller |
| 8 | + |
| 9 | +maintainers: |
| 10 | + |
| 11 | + |
| 12 | +description: | |
| 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' |
| 32 | +select: |
| 33 | + properties: |
| 34 | + compatible: |
| 35 | + contains: |
| 36 | + enum: |
| 37 | + - arm,mhu |
| 38 | + - arm,mhu-doorbell |
| 39 | + required: |
| 40 | + - compatible |
| 41 | + |
| 42 | +properties: |
| 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 | + maxItems: 3 |
| 65 | + |
| 66 | + clocks: |
| 67 | + maxItems: 1 |
| 68 | + |
| 69 | + clock-names: |
| 70 | + items: |
| 71 | + - const: apb_pclk |
| 72 | + |
| 73 | + '#mbox-cells': |
| 74 | + description: | |
| 75 | + Set to 1 in data transfer mode and represents index of the channel. |
| 76 | + Set to 2 in doorbell mode and represents index of the channel and doorbell |
| 77 | + number. |
| 78 | + enum: [ 1, 2 ] |
| 79 | + |
| 80 | +required: |
| 81 | + - compatible |
| 82 | + - reg |
| 83 | + - interrupts |
| 84 | + - '#mbox-cells' |
| 85 | + |
| 86 | +additionalProperties: false |
| 87 | + |
| 88 | +examples: |
| 89 | + # Data transfer mode. |
| 90 | + - | |
| 91 | + soc { |
| 92 | + #address-cells = <2>; |
| 93 | + #size-cells = <2>; |
| 94 | +
|
| 95 | + mhuA: mailbox@2b1f0000 { |
| 96 | + #mbox-cells = <1>; |
| 97 | + compatible = "arm,mhu", "arm,primecell"; |
| 98 | + reg = <0 0x2b1f0000 0 0x1000>; |
| 99 | + interrupts = <0 36 4>, /* LP-NonSecure */ |
| 100 | + <0 35 4>, /* HP-NonSecure */ |
| 101 | + <0 37 4>; /* Secure */ |
| 102 | + clocks = <&clock 0 2 1>; |
| 103 | + clock-names = "apb_pclk"; |
| 104 | + }; |
| 105 | +
|
| 106 | + mhu_client_scb: scb@2e000000 { |
| 107 | + compatible = "fujitsu,mb86s70-scb-1.0"; |
| 108 | + reg = <0 0x2e000000 0 0x4000>; |
| 109 | + mboxes = <&mhuA 1>; /* HP-NonSecure */ |
| 110 | + }; |
| 111 | + }; |
| 112 | +
|
| 113 | + # Doorbell mode. |
| 114 | + - | |
| 115 | + soc { |
| 116 | + #address-cells = <2>; |
| 117 | + #size-cells = <2>; |
| 118 | +
|
| 119 | + mhuB: mailbox@2b2f0000 { |
| 120 | + #mbox-cells = <2>; |
| 121 | + compatible = "arm,mhu-doorbell", "arm,primecell"; |
| 122 | + reg = <0 0x2b2f0000 0 0x1000>; |
| 123 | + interrupts = <0 36 4>, /* LP-NonSecure */ |
| 124 | + <0 35 4>, /* HP-NonSecure */ |
| 125 | + <0 37 4>; /* Secure */ |
| 126 | + clocks = <&clock 0 2 1>; |
| 127 | + clock-names = "apb_pclk"; |
| 128 | + }; |
| 129 | +
|
| 130 | + mhu_client_scpi: scpi@2f000000 { |
| 131 | + compatible = "arm,scpi"; |
| 132 | + reg = <0 0x2f000000 0 0x200>; |
| 133 | + mboxes = <&mhuB 1 4>; /* HP-NonSecure, 5th doorbell */ |
| 134 | + }; |
| 135 | + }; |
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