Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753075AbdHDOg3 (ORCPT ); Fri, 4 Aug 2017 10:36:29 -0400 Received: from foss.arm.com ([217.140.101.70]:54200 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752160AbdHDOcJ (ORCPT ); Fri, 4 Aug 2017 10:32:09 -0400 From: Sudeep Holla To: ALKML , LKML , DTML Cc: Sudeep Holla , Roy Franz , Harb Abdulhamid , Nishanth Menon , Arnd Bergmann , Loc Ho , Alexey Klimov , Ryan Harkin , Jassi Brar , Rob Herring , Mark Rutland Subject: [PATCH v2 02/18] dt-bindings: arm: add support for ARM System Control and Management Interface(SCMI) protocol Date: Fri, 4 Aug 2017 15:31:28 +0100 Message-Id: <1501857104-11279-3-git-send-email-sudeep.holla@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1501857104-11279-1-git-send-email-sudeep.holla@arm.com> References: <1501857104-11279-1-git-send-email-sudeep.holla@arm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6380 Lines: 203 This patch adds devicetree binding for System Control and Management Interface (SCMI) Message Protocol used between the Application Cores(AP) and the System Control Processor(SCP). The MHU peripheral provides a mechanism for inter-processor communication between SCP's M3 processor and AP. SCP offers control and management of the core/cluster power states, various power domain DVFS including the core/cluster, certain system clocks configuration, thermal sensors and many others. SCMI protocol is developed as better replacement to the existing SCPI which is not flexible and easily extensible. Cc: Rob Herring Cc: Mark Rutland Signed-off-by: Sudeep Holla --- Documentation/devicetree/bindings/arm/arm,scmi.txt | 174 +++++++++++++++++++++ 1 file changed, 174 insertions(+) create mode 100644 Documentation/devicetree/bindings/arm/arm,scmi.txt diff --git a/Documentation/devicetree/bindings/arm/arm,scmi.txt b/Documentation/devicetree/bindings/arm/arm,scmi.txt new file mode 100644 index 000000000000..33c16be58e72 --- /dev/null +++ b/Documentation/devicetree/bindings/arm/arm,scmi.txt @@ -0,0 +1,174 @@ +System Control and Management Interface (SCMI) Message Protocol +---------------------------------------------------------- + +The SCMI is intended to allow agents such as OSPM to manage various functions +that are provided by the hardware platform it is running on, including power +and performance functions. + +This binding is intended to define the interface the firmware implementing +the SCMI as described in ARM document number ARM DUI 0922B ("ARM System Control +and Management Interface Platform Design Document")[0] provide for OSPM in +the device tree. + +Required properties: + +- compatible : shall be "arm,scmi" +- mboxes: List of phandle and mailbox channel specifiers. It should contain + exactly one or two mailboxes, one for transmitting messages("tx") + and another optional for receiving the notifications("rx") if + supported. +- mbox-names: shall be "tx" or "rx" +- shmem : List of phandle pointing to the shared memory(SHM) area as per + generic mailbox client binding. + +See Documentation/devicetree/bindings/mailbox/mailbox.txt for more details +about the generic mailbox controller and client driver bindings. + +The mailbox is the only permitted method of calling the SCMI firmware. +Mailbox doorbell is used as a mechanism to alert the presence of a +messages and/or notification. + +Each protocol supported shall have a sub-node with corresponding compatible +as described in the following sections. If the platform supports dedicated +communication channel for a particular protocol, the 3 properties namely: +mboxes, mbox-names and shmem shall be present in the sub-node corresponding +to that protocol. + +Clock/Performance bindings for the clocks/OPPs based on SCMI Message Protocol +------------------------------------------------------------ + +This binding uses the common clock binding[1]. + +Required properties: +- #clock-cells : Should be 1. Contains the Clock ID value used by SCMI commands. + +Power domain bindings for the power domains based on SCMI Message Protocol +------------------------------------------------------------ + +This binding uses the generic power domain binding[4]. + +PM domain providers +=================== + +Required properties: + - #power-domain-cells : Should be 1. Contains the device or the power + domain ID value used by SCMI commands. + +PM domain consumers +=================== + +Required properties: + - power-domains : A phandle and PM domain specifier as defined by bindings of + the power controller specified by phandle. + +Sensor bindings for the sensors based on SCMI Message Protocol +-------------------------------------------------------------- +SCMI provides an API to access the various sensors on the SoC. + +Required properties: +- #thermal-sensor-cells: should be set to 1. This property follows the + thermal device tree bindings[2]. + + Valid cell values are raw identifiers (Sensor ID) + as used by the firmware. Refer to platform details + for your implementation for the IDs to use. + +SRAM and Shared Memory for SCMI +------------------------------- + +A small area of SRAM is reserved for SCMI communication between application +processors and SCP. + +The properties should follow the generic mmio-sram description found in [3] + +Each sub-node represents the reserved area for SCMI. + +Required sub-node properties: +- reg : The base offset and size of the reserved area with the SRAM +- compatible : should be "arm,scmi-shmem" for Non-secure SRAM based + shared memory + +[0] http://infocenter.arm.com/help/topic/com.arm.doc.den0056a/index.html +[1] Documentation/devicetree/bindings/clock/clock-bindings.txt +[2] Documentation/devicetree/bindings/thermal/thermal.txt +[3] Documentation/devicetree/bindings/sram/sram.txt +[4] Documentation/devicetree/bindings/power/power_domain.txt + +Example: + +sram: sram@50000000 { + compatible = "mmio-sram"; + reg = <0x0 0x50000000 0x0 0x10000>; + + #address-cells = <1>; + #size-cells = <1>; + ranges = <0 0x0 0x50000000 0x10000>; + + cpu_scp_lpri: scp-shmem@0 { + compatible = "arm,scmi-shmem"; + reg = <0x0 0x200>; + }; + + cpu_scp_hpri: scp-shmem@200 { + compatible = "arm,scmi-shmem"; + reg = <0x200 0x200>; + }; +}; + +mailbox: mailbox0@40000000 { + .... + #mbox-cells = <1>; +}; + +scmi_protocol: scmi@2e000000 { + compatible = "arm,scmi"; + method = "mailbox-doorbell"; + mboxes = <&mailbox 0 &mailbox 1>; + shmem = <&cpu_scp_lpri &cpu_scp_hpri>; + #address-cells = <1>; + #size-cells = <0>; + + scmi_devpd: protocol@11 { + reg = <0x11>; + #power-domain-cells = <1>; + }; + + scmi_dvfs: protocol@13 { + reg = <0x13>; + #clock-cells = <1>; + }; + + scmi_clk: protocol@14 { + reg = <0x14>; + #clock-cells = <1>; + }; + + scmi_sensors0: protocol@15 { + reg = <0x15>; + #thermal-sensor-cells = <1>; + }; +}; + +cpu@0 { + ... + reg = <0 0>; + clocks = <&scmi_dvfs 0>; +}; + +hdlcd@7ff60000 { + ... + reg = <0 0x7ff60000 0 0x1000>; + clocks = <&scmi_clk 4>; + power-domains = <&scmi_devpd 1>; +}; + +thermal-zones { + soc_thermal { + polling-delay-passive = <100>; + polling-delay = <1000>; + + /* sensor ID */ + thermal-sensors = <&scmi_sensors0 3>; + ... + }; +}; -- 2.7.4