arm,mhu.yaml

  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  reg:
 56    maxItems: 1
 57
 58  interrupts:
 59    minItems: 2
 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
106    firmware {
107        scpi {
108            compatible = "arm,scpi";
109            mboxes = <&mhuA 1>; /* HP-NonSecure */
110            shmem = <&cpu_scp_hpri>; /* HP-NonSecure */
111
112            scpi_devpd: power-controller {
113                compatible = "arm,scpi-power-domains";
114                num-domains = <2>;
115                #power-domain-cells = <1>;
116            };
117        };
118    };
119
120  # Doorbell mode.
121  - |
122    soc {
123        #address-cells = <2>;
124        #size-cells = <2>;
125
126        mhuB: mailbox@2b2f0000 {
127            #mbox-cells = <2>;
128            compatible = "arm,mhu-doorbell", "arm,primecell";
129            reg = <0 0x2b2f0000 0 0x1000>;
130            interrupts = <0 36 4>, /* LP-NonSecure */
131                         <0 35 4>, /* HP-NonSecure */
132                         <0 37 4>; /* Secure */
133            clocks = <&clock 0 2 1>;
134            clock-names = "apb_pclk";
135        };
136    };
137
138    firmware {
139        scmi {
140            compatible = "arm,scmi";
141            mboxes = <&mhuB 0 0>, /* LP-NonSecure, 1st doorbell */
142                     <&mhuB 0 1>; /* LP-NonSecure, 2nd doorbell */
143            mbox-names = "tx", "rx";
144            shmem = <&cpu_scp_lpri0>,
145                    <&cpu_scp_lpri1>;
146
147            #address-cells = <1>;
148            #size-cells = <0>;
149
150            scmi_devpd: protocol@11 {
151                reg = <0x11>;
152                #power-domain-cells = <1>;
153            };
154
155            scmi_dvfs: protocol@13 {
156                reg = <0x13>;
157                #clock-cells = <1>;
158
159                mboxes = <&mhuB 1 2>, /* HP-NonSecure, 3rd doorbell */
160                         <&mhuB 1 3>; /* HP-NonSecure, 4th doorbell */
161                mbox-names = "tx", "rx";
162                shmem = <&cpu_scp_hpri0>,
163                        <&cpu_scp_hpri1>;
164            };
165        };
166    };
167
168...