doc: driver-model: Convert remoteproc-framework.txt to reST
Convert plain text documentation to reStructuredText format and add
it to Sphinx TOC tree. No essential content change.
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/doc/driver-model/remoteproc-framework.rst b/doc/driver-model/remoteproc-framework.rst
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+.. SPDX-License-Identifier: GPL-2.0+
+.. (C) Copyright 2015
+.. Texas Instruments Incorporated - http://www.ti.com/
+
+Remote Processor Framework
+==========================
+
+Introduction
+------------
+
+This is an introduction to driver-model for Remote Processors found
+on various System on Chip(SoCs). The term remote processor is used to
+indicate that this is not the processor on which U-Boot is operating
+on, instead is yet another processing entity that may be controlled by
+the processor on which we are functional.
+
+The simplified model depends on a single UCLASS - UCLASS_REMOTEPROC
+
+UCLASS_REMOTEPROC:
+ - drivers/remoteproc/rproc-uclass.c
+ - include/remoteproc.h
+
+Commands:
+ - common/cmd_remoteproc.c
+
+Configuration:
+ - CONFIG_REMOTEPROC is selected by drivers as needed
+ - CONFIG_CMD_REMOTEPROC for the commands if required.
+
+How does it work - The driver
+-----------------------------
+
+Overall, the driver statemachine transitions are typically as follows::
+
+ (entry)
+ +-------+
+ +---+ init |
+ | | | <---------------------+
+ | +-------+ |
+ | |
+ | |
+ | +--------+ |
+ Load| | reset | |
+ | | | <----------+ |
+ | +--------+ | |
+ | |Load | |
+ | | | |
+ | +----v----+ reset | |
+ +-> | | (opt) | |
+ | Loaded +-----------+ |
+ | | |
+ +----+----+ |
+ | Start |
+ +---v-----+ (opt) |
+ +->| Running | Stop |
+ Ping +- | +--------------------+
+ (opt) +---------+
+
+(is_running does not change state)
+opt: Optional state transition implemented by driver.
+
+NOTE: It depends on the remote processor as to the exact behavior
+of the statemachine, remoteproc core does not intent to implement
+statemachine logic. Certain processors may allow start/stop without
+reloading the image in the middle, certain other processors may only
+allow us to start the processor(image from a EEPROM/OTP) etc.
+
+It is hence the responsibility of the driver to handle the requisite
+state transitions of the device as necessary.
+
+Basic design assumptions:
+
+Remote processor can operate on a certain firmware that maybe loaded
+and released from reset.
+
+The driver follows a standard UCLASS DM.
+
+in the bare minimum form:
+
+.. code-block:: c
+
+ static const struct dm_rproc_ops sandbox_testproc_ops = {
+ .load = sandbox_testproc_load,
+ .start = sandbox_testproc_start,
+ };
+
+ static const struct udevice_id sandbox_ids[] = {
+ {.compatible = "sandbox,test-processor"},
+ {}
+ };
+
+ U_BOOT_DRIVER(sandbox_testproc) = {
+ .name = "sandbox_test_proc",
+ .of_match = sandbox_ids,
+ .id = UCLASS_REMOTEPROC,
+ .ops = &sandbox_testproc_ops,
+ .probe = sandbox_testproc_probe,
+ };
+
+This allows for the device to be probed as part of the "init" command
+or invocation of 'rproc_init()' function as the system dependencies define.
+
+The driver is expected to maintain it's own statemachine which is
+appropriate for the device it maintains. It must, at the very least
+provide a load and start function. We assume here that the device
+needs to be loaded and started, else, there is no real purpose of
+using the remoteproc framework.
+
+Describing the device using platform data
+-----------------------------------------
+
+*IMPORTANT* NOTE: THIS SUPPORT IS NOT MEANT FOR USE WITH NEWER PLATFORM
+SUPPORT. THIS IS ONLY FOR LEGACY DEVICES. THIS MODE OF INITIALIZATION
+*WILL* BE EVENTUALLY REMOVED ONCE ALL NECESSARY PLATFORMS HAVE MOVED
+TO DM/FDT.
+
+Considering that many platforms are yet to move to device-tree model,
+a simplified definition of a device is as follows:
+
+.. code-block:: c
+
+ struct dm_rproc_uclass_pdata proc_3_test = {
+ .name = "proc_3_legacy",
+ .mem_type = RPROC_INTERNAL_MEMORY_MAPPED,
+ .driver_plat_data = &mydriver_data;
+ };
+
+ U_BOOT_DEVICE(proc_3_demo) = {
+ .name = "sandbox_test_proc",
+ .platdata = &proc_3_test,
+ };
+
+There can be additional data that may be desired depending on the
+remoteproc driver specific needs (for example: SoC integration
+details such as clock handle or something similar). See appropriate
+documentation for specific remoteproc driver for further details.
+These are passed via driver_plat_data.
+
+Describing the device using device tree
+---------------------------------------
+
+.. code-block: none
+
+ / {
+ ...
+ aliases {
+ ...
+ remoteproc0 = &rproc_1;
+ remoteproc1 = &rproc_2;
+
+ };
+ ...
+
+ rproc_1: rproc@1 {
+ compatible = "sandbox,test-processor";
+ remoteproc-name = "remoteproc-test-dev1";
+ };
+
+ rproc_2: rproc@2 {
+ compatible = "sandbox,test-processor";
+ internal-memory-mapped;
+ remoteproc-name = "remoteproc-test-dev2";
+ };
+ ...
+ };
+
+aliases usage is optional, but it is usually recommended to ensure the
+users have a consistent usage model for a platform.
+the compatible string used here is specific to the remoteproc driver involved.