OMAP4+ Remoteproc Devices ========================= The OMAP family of SoCs usually have one or more slave processor sub-systems that are used to offload some of the processor-intensive tasks, or to manage other hardware accelerators, for achieving various system level goals. The processor cores in the sub-system are usually behind an IOMMU, and may contain additional sub-modules like Internal RAM and/or ROMs, L1 and/or L2 caches, an Interrupt Controller, a Cache Controller etc. The OMAP SoCs usually have a DSP processor sub-system and/or an IPU processor sub-system. The DSP processor sub-system can contain any of the TI's C64x, C66x or C67x family of DSP cores as the main execution unit. The IPU processor sub-system usually contains either a Dual-Core Cortex-M3 or Dual-Core Cortex-M4 processors. Remote Processor Node: ====================== Each remote processor sub-system is represented as a single DT node. Each node has a number of required or optional properties that enable the OS running on the host processor (MPU) to perform the device management of the remote processor and to communicate with the remote processor. The various properties can be classified as constant or variable. The constant properties are dictated by the SoC and does not change from one board to another having the same SoC. Examples of constant properties include 'iommus', 'reg'. The variable properties are dictated by the system integration aspects such as memory on the board, or configuration used within the corresponding firmware image. Examples of variable properties include 'mboxes', 'memory-region', 'timers', 'watchdog-timers' etc. Required properties: -------------------- The following are the mandatory properties: - compatible: Should be one of the following, "ti,omap4-dsp" for DSPs on OMAP4 SoCs "ti,omap5-dsp" for DSPs on OMAP5 SoCs "ti,dra7-dsp" for DSPs on DRA7xx SoCs "ti,omap4-ipu" for IPUs on OMAP4 SoCs "ti,omap5-ipu" for IPUs on OMAP5 SoCs "ti,dra7-ipu" for IPUs on DRA7xx SoCs - ti,hwmods: Name of the hwmod associated with the remoteproc device - iommus: phandles to OMAP IOMMU nodes, that need to be programmed for this remote processor to access any external RAM memory or other peripheral device address spaces. This property usually has only a single phandle. Multiple phandles are used only in cases where the sub-system has different ports for different sub-modules within the processor sub-system (eg: DRA7 DSPs), and need the same programming in both the MMUs. - mboxes: OMAP Mailbox specifier denoting the sub-mailbox, to be used for communication with the remote processor. The specifier format is as per the bindings, Documentation/devicetree/bindings/mailbox/omap-mailbox.txt This property should match with the sub-mailbox node used in the firmware image. Optional properties: -------------------- Some of these properties are mandatory on some SoCs, and some are optional depending on the configuration of the firmware image to be executed on the remote processor. The conditions are mentioned for each property. The following are the optional properties: - reg: Address space for any remoteproc memories present on the SoC. Should contain an entry for each value in 'reg-names'. These are mandatory for all DSP and IPU processors that have them (OMAP4/OMAP5 DSPs do not have any RAMs) - reg-names: Required names for each of the address spaces defined in the 'reg' property. Should contain a string from among the following names, each representing the corresponding internal RAM memory region, "l2ram" for L2 RAM, "l1pram" for L1 Program RAM Memory/Cache, "l1dram" for L1 Data RAM Memory/Cache, All devices may not have all the above memories. - syscon-bootreg: Should be a pair of the phandle to the System Control Configuration region that contains the boot address register, and the register offset of the boot address register within the System Control module. This property is required for all the DSP instances on OMAP4, OMAP5 and DRA7xx SoCs. - memory-region: phandle to the reserved memory node to be associated with the remoteproc device. The reserved memory node should be a CMA memory node, and should be defined as per the bindings, Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt - mbox-names: Optional names for the OMAP mailbox specifiers mentioned in the 'mboxes' property, one per specifier value - timers: One or more phandles to OMAP DMTimer nodes, that serve as System/Tick timers for the OS running on the remote processors. This will usually be a single timer if the processor sub-system is running in SMP mode, or one per core in the processor sub-system. This property is mandatory on remote processors requiring external tick wakeup, and to support Power Management features. The timers to be used should match with the timers used in the firmware image. - watchdog-timers: One or more phandles to OMAP DMTimer nodes, used to serve as Watchdog timers for the processor cores. This will usually be one per executing processor core, even if the processor sub-system is running a SMP OS. The timers to be used should match with the watchdog timers used in the firmware image. - ti,rproc-standby-info: Standby data for the remote processor. This is mandatory to support Power Management for the OMAP remoteprocs, and should contain the address containing the module standby status. Example: -------- /* OMAP4 DSP node in SoC DTS file */ ocp { dsp: dsp { compatible = "ti,omap4-dsp"; ti,hwmods = "dsp"; syscon-bootreg = <&scm_conf 0x304>; iommus = <&mmu_dsp>; mboxes = <&mailbox &mbox_dsp>; ti,rproc-standby-info = <0x4a004420>; status = "disabled"; }; }; /* OMAP4 DSP node additional fields in a Board DTS file */ &dsp { status = "okay"; memory-region = <&dsp_cma_pool>; timers = <&timer5>; watchdog-timers = <&timer6>; };