Message-Id: <20241017011124.69257-1-yesanishhere@gmail.com>
Date: Wed, 16 Oct 2024 18:11:23 -0700
From: anish kumar <yesanishhere@...il.com>
To: andersson@...nel.org,
	mathieu.poirier@...aro.orgi,
	corbet@....net
Cc: linux-doc@...r.kernel.org,
	linux-remoteproc@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	anish kumar <yesanishhere@...il.com>
Subject: [PATCH v2 1/2] remoteproc: Documentation: move from staging

In preparation of making the documentation
mainline. Remove the documentation from staging.

Signed-off-by: anish kumar <yesanishhere@...il.com>
---
v2:
| Reported-by: kernel test robot <lkp@...el.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202410161444.jOKMsoGS-lkp@intel.com/

 Documentation/staging/remoteproc.rst | 359 ---------------------------
 MAINTAINERS                          |   1 -
 2 files changed, 360 deletions(-)
 delete mode 100644 Documentation/staging/remoteproc.rst

diff --git a/Documentation/staging/remoteproc.rst b/Documentation/staging/remoteproc.rst
deleted file mode 100644
index 9cccd3dd6a4b..000000000000
--- a/Documentation/staging/remoteproc.rst
+++ /dev/null
@@ -1,359 +0,0 @@
-==========================
-Remote Processor Framework
-==========================
-
-Introduction
-============
-
-Modern SoCs typically have heterogeneous remote processor devices in asymmetric
-multiprocessing (AMP) configurations, which may be running different instances
-of operating system, whether it's Linux or any other flavor of real-time OS.
-
-OMAP4, for example, has dual Cortex-A9, dual Cortex-M3 and a C64x+ DSP.
-In a typical configuration, the dual cortex-A9 is running Linux in a SMP
-configuration, and each of the other three cores (two M3 cores and a DSP)
-is running its own instance of RTOS in an AMP configuration.
-
-The remoteproc framework allows different platforms/architectures to
-control (power on, load firmware, power off) those remote processors while
-abstracting the hardware differences, so the entire driver doesn't need to be
-duplicated. In addition, this framework also adds rpmsg virtio devices
-for remote processors that supports this kind of communication. This way,
-platform-specific remoteproc drivers only need to provide a few low-level
-handlers, and then all rpmsg drivers will then just work
-(for more information about the virtio-based rpmsg bus and its drivers,
-please read Documentation/staging/rpmsg.rst).
-Registration of other types of virtio devices is now also possible. Firmwares
-just need to publish what kind of virtio devices do they support, and then
-remoteproc will add those devices. This makes it possible to reuse the
-existing virtio drivers with remote processor backends at a minimal development
-cost.
-
-User API
-========
-
-::
-
-  int rproc_boot(struct rproc *rproc)
-
-Boot a remote processor (i.e. load its firmware, power it on, ...).
-
-If the remote processor is already powered on, this function immediately
-returns (successfully).
-
-Returns 0 on success, and an appropriate error value otherwise.
-Note: to use this function you should already have a valid rproc
-handle. There are several ways to achieve that cleanly (devres, pdata,
-the way remoteproc_rpmsg.c does this, or, if this becomes prevalent, we
-might also consider using dev_archdata for this).
-
-::
-
-  void rproc_shutdown(struct rproc *rproc)
-
-Power off a remote processor (previously booted with rproc_boot()).
-In case @rproc is still being used by an additional user(s), then
-this function will just decrement the power refcount and exit,
-without really powering off the device.
-
-Every call to rproc_boot() must (eventually) be accompanied by a call
-to rproc_shutdown(). Calling rproc_shutdown() redundantly is a bug.
-
-.. note::
-
-  we're not decrementing the rproc's refcount, only the power refcount.
-  which means that the @rproc handle stays valid even after
-  rproc_shutdown() returns, and users can still use it with a subsequent
-  rproc_boot(), if needed.
-
-::
-
-  struct rproc *rproc_get_by_phandle(phandle phandle)
-
-Find an rproc handle using a device tree phandle. Returns the rproc
-handle on success, and NULL on failure. This function increments
-the remote processor's refcount, so always use rproc_put() to
-decrement it back once rproc isn't needed anymore.
-
-Typical usage
-=============
-
-::
-
-  #include <linux/remoteproc.h>
-
-  /* in case we were given a valid 'rproc' handle */
-  int dummy_rproc_example(struct rproc *my_rproc)
-  {
-	int ret;
-
-	/* let's power on and boot our remote processor */
-	ret = rproc_boot(my_rproc);
-	if (ret) {
-		/*
-		 * something went wrong. handle it and leave.
-		 */
-	}
-
-	/*
-	 * our remote processor is now powered on... give it some work
-	 */
-
-	/* let's shut it down now */
-	rproc_shutdown(my_rproc);
-  }
-
-API for implementors
-====================
-
-::
-
-  struct rproc *rproc_alloc(struct device *dev, const char *name,
-				const struct rproc_ops *ops,
-				const char *firmware, int len)
-
-Allocate a new remote processor handle, but don't register
-it yet. Required parameters are the underlying device, the
-name of this remote processor, platform-specific ops handlers,
-the name of the firmware to boot this rproc with, and the
-length of private data needed by the allocating rproc driver (in bytes).
-
-This function should be used by rproc implementations during
-initialization of the remote processor.
-
-After creating an rproc handle using this function, and when ready,
-implementations should then call rproc_add() to complete
-the registration of the remote processor.
-
-On success, the new rproc is returned, and on failure, NULL.
-
-.. note::
-
-  **never** directly deallocate @rproc, even if it was not registered
-  yet. Instead, when you need to unroll rproc_alloc(), use rproc_free().
-
-::
-
-  void rproc_free(struct rproc *rproc)
-
-Free an rproc handle that was allocated by rproc_alloc.
-
-This function essentially unrolls rproc_alloc(), by decrementing the
-rproc's refcount. It doesn't directly free rproc; that would happen
-only if there are no other references to rproc and its refcount now
-dropped to zero.
-
-::
-
-  int rproc_add(struct rproc *rproc)
-
-Register @rproc with the remoteproc framework, after it has been
-allocated with rproc_alloc().
-
-This is called by the platform-specific rproc implementation, whenever
-a new remote processor device is probed.
-
-Returns 0 on success and an appropriate error code otherwise.
-Note: this function initiates an asynchronous firmware loading
-context, which will look for virtio devices supported by the rproc's
-firmware.
-
-If found, those virtio devices will be created and added, so as a result
-of registering this remote processor, additional virtio drivers might get
-probed.
-
-::
-
-  int rproc_del(struct rproc *rproc)
-
-Unroll rproc_add().
-
-This function should be called when the platform specific rproc
-implementation decides to remove the rproc device. it should
-_only_ be called if a previous invocation of rproc_add()
-has completed successfully.
-
-After rproc_del() returns, @rproc is still valid, and its
-last refcount should be decremented by calling rproc_free().
-
-Returns 0 on success and -EINVAL if @rproc isn't valid.
-
-::
-
-  void rproc_report_crash(struct rproc *rproc, enum rproc_crash_type type)
-
-Report a crash in a remoteproc
-
-This function must be called every time a crash is detected by the
-platform specific rproc implementation. This should not be called from a
-non-remoteproc driver. This function can be called from atomic/interrupt
-context.
-
-Implementation callbacks
-========================
-
-These callbacks should be provided by platform-specific remoteproc
-drivers::
-
-  /**
-   * struct rproc_ops - platform-specific device handlers
-   * @start:	power on the device and boot it
-   * @stop:	power off the device
-   * @kick:	kick a virtqueue (virtqueue id given as a parameter)
-   */
-  struct rproc_ops {
-	int (*start)(struct rproc *rproc);
-	int (*stop)(struct rproc *rproc);
-	void (*kick)(struct rproc *rproc, int vqid);
-  };
-
-Every remoteproc implementation should at least provide the ->start and ->stop
-handlers. If rpmsg/virtio functionality is also desired, then the ->kick handler
-should be provided as well.
-
-The ->start() handler takes an rproc handle and should then power on the
-device and boot it (use rproc->priv to access platform-specific private data).
-The boot address, in case needed, can be found in rproc->bootaddr (remoteproc
-core puts there the ELF entry point).
-On success, 0 should be returned, and on failure, an appropriate error code.
-
-The ->stop() handler takes an rproc handle and powers the device down.
-On success, 0 is returned, and on failure, an appropriate error code.
-
-The ->kick() handler takes an rproc handle, and an index of a virtqueue
-where new message was placed in. Implementations should interrupt the remote
-processor and let it know it has pending messages. Notifying remote processors
-the exact virtqueue index to look in is optional: it is easy (and not
-too expensive) to go through the existing virtqueues and look for new buffers
-in the used rings.
-
-Binary Firmware Structure
-=========================
-
-At this point remoteproc supports ELF32 and ELF64 firmware binaries. However,
-it is quite expected that other platforms/devices which we'd want to
-support with this framework will be based on different binary formats.
-
-When those use cases show up, we will have to decouple the binary format
-from the framework core, so we can support several binary formats without
-duplicating common code.
-
-When the firmware is parsed, its various segments are loaded to memory
-according to the specified device address (might be a physical address
-if the remote processor is accessing memory directly).
-
-In addition to the standard ELF segments, most remote processors would
-also include a special section which we call "the resource table".
-
-The resource table contains system resources that the remote processor
-requires before it should be powered on, such as allocation of physically
-contiguous memory, or iommu mapping of certain on-chip peripherals.
-Remotecore will only power up the device after all the resource table's
-requirement are met.
-
-In addition to system resources, the resource table may also contain
-resource entries that publish the existence of supported features
-or configurations by the remote processor, such as trace buffers and
-supported virtio devices (and their configurations).
-
-The resource table begins with this header::
-
-  /**
-   * struct resource_table - firmware resource table header
-   * @ver: version number
-   * @num: number of resource entries
-   * @reserved: reserved (must be zero)
-   * @offset: array of offsets pointing at the various resource entries
-   *
-   * The header of the resource table, as expressed by this structure,
-   * contains a version number (should we need to change this format in the
-   * future), the number of available resource entries, and their offsets
-   * in the table.
-   */
-  struct resource_table {
-	u32 ver;
-	u32 num;
-	u32 reserved[2];
-	u32 offset[0];
-  } __packed;
-
-Immediately following this header are the resource entries themselves,
-each of which begins with the following resource entry header::
-
-  /**
-   * struct fw_rsc_hdr - firmware resource entry header
-   * @type: resource type
-   * @data: resource data
-   *
-   * Every resource entry begins with a 'struct fw_rsc_hdr' header providing
-   * its @type. The content of the entry itself will immediately follow
-   * this header, and it should be parsed according to the resource type.
-   */
-  struct fw_rsc_hdr {
-	u32 type;
-	u8 data[0];
-  } __packed;
-
-Some resources entries are mere announcements, where the host is informed
-of specific remoteproc configuration. Other entries require the host to
-do something (e.g. allocate a system resource). Sometimes a negotiation
-is expected, where the firmware requests a resource, and once allocated,
-the host should provide back its details (e.g. address of an allocated
-memory region).
-
-Here are the various resource types that are currently supported::
-
-  /**
-   * enum fw_resource_type - types of resource entries
-   *
-   * @RSC_CARVEOUT:   request for allocation of a physically contiguous
-   *		    memory region.
-   * @RSC_DEVMEM:     request to iommu_map a memory-based peripheral.
-   * @RSC_TRACE:	    announces the availability of a trace buffer into which
-   *		    the remote processor will be writing logs.
-   * @RSC_VDEV:       declare support for a virtio device, and serve as its
-   *		    virtio header.
-   * @RSC_LAST:       just keep this one at the end
-   * @RSC_VENDOR_START:	start of the vendor specific resource types range
-   * @RSC_VENDOR_END:	end of the vendor specific resource types range
-   *
-   * Please note that these values are used as indices to the rproc_handle_rsc
-   * lookup table, so please keep them sane. Moreover, @RSC_LAST is used to
-   * check the validity of an index before the lookup table is accessed, so
-   * please update it as needed.
-   */
-  enum fw_resource_type {
-	RSC_CARVEOUT		= 0,
-	RSC_DEVMEM		= 1,
-	RSC_TRACE		= 2,
-	RSC_VDEV		= 3,
-	RSC_LAST		= 4,
-	RSC_VENDOR_START	= 128,
-	RSC_VENDOR_END		= 512,
-  };
-
-For more details regarding a specific resource type, please see its
-dedicated structure in include/linux/remoteproc.h.
-
-We also expect that platform-specific resource entries will show up
-at some point. When that happens, we could easily add a new RSC_PLATFORM
-type, and hand those resources to the platform-specific rproc driver to handle.
-
-Virtio and remoteproc
-=====================
-
-The firmware should provide remoteproc information about virtio devices
-that it supports, and their configurations: a RSC_VDEV resource entry
-should specify the virtio device id (as in virtio_ids.h), virtio features,
-virtio config space, vrings information, etc.
-
-When a new remote processor is registered, the remoteproc framework
-will look for its resource table and will register the virtio devices
-it supports. A firmware may support any number of virtio devices, and
-of any type (a single remote processor can also easily support several
-rpmsg virtio devices this way, if desired).
-
-Of course, RSC_VDEV resource entries are only good enough for static
-allocation of virtio devices. Dynamic allocations will also be made possible
-using the rpmsg bus (similar to how we already do dynamic allocations of
-rpmsg channels; read more about it in rpmsg.txt).
diff --git a/MAINTAINERS b/MAINTAINERS
index eeb4c70b3d5b..c0aa32970d07 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15907,7 +15907,6 @@ S:	Maintained
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/andersson/remoteproc.git rproc-next
 F:	Documentation/ABI/testing/sysfs-class-remoteproc
 F:	Documentation/devicetree/bindings/remoteproc/
-F:	Documentation/staging/remoteproc.rst
 F:	drivers/remoteproc/
 F:	include/linux/remoteproc.h
 F:	include/linux/remoteproc/
-- 
2.39.3 (Apple Git-146)

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