Re: [PATCH] remoteproc: Documentation: upgrade from staging.

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Hi Anish,

First and foremost, there are kernel bot problems to fix.

On Mon, Oct 14, 2024 at 07:58:31PM -0700, anish kumar wrote:
> Add the documentation in the mainline from
> staging and add the relvant information from
> current mainline.
> 
> Added:
> 1. userspace api documentation.
> 2. kernel api documentation.
> 3. Driver framework core details added.

You are doing everything in the same patch, making it impossible for me to
understand what is just a move from staging to core and what is new material.
First do a patch that does the move and then do the enhancements, one topic at a
time.

Thanks,
Mathieu

> 
> Signed-off-by: anish kumar <yesanishhere@xxxxxxxxx>
> ---
>  Documentation/remoteproc/core.rst             | 252 ++++++++++++
>  Documentation/remoteproc/index.rst            |  27 ++
>  Documentation/remoteproc/rproc-api.rst        |  75 ++++
>  Documentation/remoteproc/rproc-kernel-api.rst | 239 ++++++++++++
>  Documentation/staging/index.rst               |   1 -
>  Documentation/staging/remoteproc.rst          | 360 ------------------
>  Documentation/staging/rpmsg.rst               |   2 +-
>  7 files changed, 594 insertions(+), 362 deletions(-)
>  create mode 100644 Documentation/remoteproc/core.rst
>  create mode 100644 Documentation/remoteproc/index.rst
>  create mode 100644 Documentation/remoteproc/rproc-api.rst
>  create mode 100644 Documentation/remoteproc/rproc-kernel-api.rst
>  delete mode 100644 Documentation/staging/remoteproc.rst
> 
> diff --git a/Documentation/remoteproc/core.rst b/Documentation/remoteproc/core.rst
> new file mode 100644
> index 000000000000..a59c2c5bc8e6
> --- /dev/null
> +++ b/Documentation/remoteproc/core.rst
> @@ -0,0 +1,252 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +===============================================
> +General description of the remoteproc subsystem
> +===============================================
> +
> +Authors:
> +	- anish kumar <yesanishhere@xxxxxxxxx>
> +
> +.. Contents:
> +
> +   1.  Introduction
> +   2.  Remoteproc framework responsibilities
> +   3.  Remoteproc driver responsibilities
> +   4.  Virtio and rpmsg
> +
> +1. Introduction
> +======================
> +
> +Modern System on Chips (SoCs) typically integrate heterogeneous remote
> +processor devices in asymmetric multiprocessing (AMP) configurations.
> +These processors may run different operating systems, such as Linux and
> +various real-time operating systems (RTOS).
> +
> +For example, the OMAP4 platform features dual Cortex-A9 cores, dual
> +Cortex-M3 cores, and a C64x+ DSP. In a standard setup, the Cortex-A9
> +cores execute Linux in a symmetric multiprocessing (SMP) configuration,
> +while the M3 cores and DSP run independent instances of an RTOS.
> +
> +The remoteproc framework allows various platforms and architectures to
> +manage remote processors, including operations such as powering on,
> +loading firmware, and powering off. This framework abstracts hardware
> +differences, promoting code reuse and minimizing duplication. It also
> +supports rpmsg virtio devices for remote processors that utilize this
> +communication method. Consequently, platform-specific remoteproc drivers
> +need only implement a few low-level handlers, enabling seamless operation
> +of all rpmsg drivers. (For more details about the virtio-based rpmsg
> +bus and its drivers, refer to :doc:`Documentation/staging/rpmsg.rst`.)
> +
> +Additionally, the framework allows for the registration of various
> +virtio devices. Firmware can publish the types of virtio devices it
> +supports, facilitating their addition to the remoteproc framework. This
> +flexibility enables the reuse of existing virtio drivers with remote
> +processor backends at minimal development cost.
> +
> +The primary purpose of the remoteproc framework is to download firmware
> +for remote processors and manage their lifecycle. The framework consists
> +of several key components:
> +
> +- **Character Driver**: Provides userspace access to control the remote
> +  processor.
> +- **ELF Utility**: Offers functions for handling ELF files and managing
> +  resources requested by the remote processor.
> +- **Remoteproc Core**: Manages firmware downloads and recovery actions
> +  in case of a remote processor crash.
> +- **Coredump**: Provides facilities for coredumping and tracing from
> +  the remote processor in the event of a crash.
> +- **Userspace Interaction**: Uses sysfs and debugfs to manage the
> +  lifecycle and status of the remote processor.
> +- **Virtio Support**: Facilitates interaction with the virtio and
> +  rpmsg bus.
> +
> +From here on, references to "framework" denote the remoteproc
> +framework, and "driver" refers to the remoteproc driver that utilizes
> +the framework for managing remote processors.
> +
> +2. Remoteproc framework Responsibilities
> +========================================
> +
> +The framework begins by gathering information about the firmware file
> +to be downloaded through the request_firmware function. It supports
> +the ELF format and parses the firmware image to identify the physical
> +addresses that need to be populated from the corresponding ELF sections.
> +The framework also requires knowledge of the logical or I/O-mapped
> +addresses in the application processor. Once this information is
> +obtained from the driver, the framework transfers the data to the
> +specified addresses and starts the remote, along with
> +any devices physically or logically connected to it.
> +
> +Dependent devices, referred to as `subdevices` within the framework,
> +are also managed post-registration by their respective drivers.
> +Subdevices can register themselves using `rproc_(add/remove)_subdev`.
> +Non-remoteproc drivers can use subdevices as a way to logically connect
> +to remote and get lifecycle notifications of the remote.
> +
> +The framework oversees the lifecycle of the remote and
> +provides the `rproc_report_crash` function, which the driver invokes
> +upon receiving a crash notification from the remote. The
> +notification method can differ based on the design of the remote
> +processor and its communication with the application processor. For
> +instance, if the remote is a DSP equipped with a watchdog,
> +unresponsive behavior triggers the watchdog, generating an interrupt
> +that routes to the application processor, allowing it to call
> +`rproc_report_crash` in the driver's interrupt context.
> +
> +During crash handling, the framework performs the following actions:
> +
> +a. Sends a request to stop the remote and any connected or
> +   dependent subdevices.
> +b. Generates a coredump, dumping all `resources` requested by the
> +   remote alongside relevant debugging information. Resources are
> +   explained below.
> +c. Reloads the firmware and restarts the remote.
> +
> +If the `RPROC_FEAT_ATTACH_ON_RECOVERY` flag is set, the detach and
> +attach callbacks of the driver are invoked without reloading the
> +firmware. This is useful when the remote requires no
> +assistance for recovery, or when the application processor can restart
> +independently. After recovery, the application processor can reattach
> +to the remote.
> +
> +The remote can request resources from the framework, which
> +allocates a ".resource_table" section. During the ELF parsing phase,
> +the framework identifies this section and calls the appropriate
> +handler to allocate the requested resources.
> +
> +Resource management within the framework can accommodate any type of
> +`fw_resource_type`.
> +
> +.. code-block:: c
> +
> +   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,
> +   };
> +
> +   struct resource_table {
> +       u32 ver;
> +       u32 num;
> +       u32 reserved[2];
> +       u32 offset[];
> +   } __packed;
> +
> +   struct fw_rsc_hdr {
> +       u32 type;
> +       u8 data[];
> +   } __packed;
> +
> +For example, if the remote requests both `RSC_TRACE` and
> +`RSC_CARVEOUT` for memory allocation, the ELF firmware can be structured
> +as follows:
> +
> +.. code-block:: c
> +
> +   #define MAX_SHARED_RESOURCE 2
> +   #define LOG_BUF_SIZE 1000
> +   #define CARVEOUT_DUMP_PA 0x12345678
> +   #define CARVEOUT_DUMP_SIZE 2000
> +
> +   struct shared_resource_table {
> +       u32 ver;
> +       u32 num;
> +       u32 reserved[2];
> +       u32 offset[MAX_SHARED_RESOURCE];
> +       struct fw_rsc_trace log_trace;
> +       struct fw_rsc_carveout dump_carveout;
> +   };
> +
> +   volatile struct shared_resource_table table = {
> +       .ver = 1,
> +       .num = 2,
> +       .reserved = {0, 0},
> +       .offset = {
> +           offsetof(struct resource_table, log_trace),
> +           offsetof(struct resource_table, dump_carveout),
> +       },
> +       .log_trace = {
> +           RSC_TRACE,
> +           (u32)log_buf, LOG_BUF_SIZE, 0, "log_trace",
> +       },
> +       .dump_carveout = {
> +           RSC_CARVEOUT,
> +           (u32)FW_RSC_ADDR_ANY, CARVEOUT_PA, 0, "carveout_dump",
> +       },
> +   };
> +
> +The framework creates a sysfs file when it encounters the `RSC_TRACE`
> +type to expose log information to userspace. Other resource types are
> +handled accordingly. In the example above, `CARVEOUT_DUMP_SIZE` bytes
> +of DMA memory will be allocated starting from `CARVEOUT_DUMP_PA`.
> +
> +
> +3. Remoteproc driver responsibilities
> +=====================================
> +
> +The driver must provide the following information to the core:
> +
> +a. Translate device addresses (physical addresses) found in the ELF
> +   firmware to virtual addresses in Linux using the `da_to_va`
> +   callback. This allows the framework to copy ELF firmware from the
> +   filesystem to the addresses expected by the remote since
> +   the framework cannot directly access those physical addresses.
> +b. Prepare/unprepare the remote prior to firmware loading,
> +   which may involve allocating carveout and reserved memory regions.
> +c. Implement methods for starting and stopping the remote,
> +   whether by setting registers or sending explicit interrupts,
> +   depending on the hardware design.
> +d. Provide attach and detach callbacks to start the remote
> +   without loading the firmware. This is beneficial when the remote
> +   processor is already loaded and running.
> +e. Implement a load callback for firmware loading, typically using
> +   the ELF loader provided by the framework; currently, only ELF
> +   format is supported.
> +f. Invoke the framework's crash handler API upon detecting a remote
> +   crash.
> +
> +Drivers must fill the `rproc_ops` structure and call `rproc_alloc`
> +to register themselves with the framework.
> +
> +.. code-block:: c
> +
> +   struct rproc_ops {
> +       int (*prepare)(struct rproc *rproc);
> +       int (*unprepare)(struct rproc *rproc);
> +       int (*start)(struct rproc *rproc);
> +       int (*stop)(struct rproc *rproc);
> +       int (*attach)(struct rproc *rproc);
> +       int (*detach)(struct rproc *rproc);
> +       void * (*da_to_va)(struct rproc *rproc, u64 da, size_t len,
> +                          bool *is_iomem);
> +       int (*parse_fw)(struct rproc *rproc, const struct firmware *fw);
> +       int (*handle_rsc)(struct rproc *rproc, u32 rsc_type,
> +                         void *rsc, int offset, int avail);
> +       int (*load)(struct rproc *rproc, const struct firmware *fw);
> +       //snip
> +   };
> +
> +
> +4. Virtio and Remoteproc
> +========================
> +
> +The firmware must provide remoteproc with information regarding the
> +virtio devices it supports and their configurations: an `RSC_VDEV`
> +resource entry should detail the virtio device ID (as defined in
> +`virtio_ids.h`), virtio features, virtio config space, vrings
> +information, etc.
> +
> +Upon registration of a new remote, the remoteproc framework
> +searches for its resource table and registers the supported virtio
> +devices. A firmware may support multiple virtio devices, of various
> +types (a single remote can support multiple rpmsg virtio
> +devices if required).
> +
> +Moreover, `RSC_VDEV` resource entries suffice for static allocation
> +of virtio devices. Dynamic allocations will also be supported using
> +the rpmsg bus, akin to the handling of dynamic allocations for rpmsg
> +channels. For more information, refer to `rpmsg.txt`.
> diff --git a/Documentation/remoteproc/index.rst b/Documentation/remoteproc/index.rst
> new file mode 100644
> index 000000000000..631797f49b32
> --- /dev/null
> +++ b/Documentation/remoteproc/index.rst
> @@ -0,0 +1,27 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +========================================================================
> +remoteproc - remote processor subsystem in Linux(TM) kernel
> +========================================================================
> +
> +Authors:
> +	- anish kumar  <yesanishhere@xxxxxxxxx>
> +
> +   remote processor subsystem is a way to manage the lifecycle of
> +   a subsytem that is external to the Linux. 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.
> +
> +.. toctree::
> +   :maxdepth: 1
> +
> +   core
> +   rproc-api
> +   rproc-kernel-api
> +
> +Mailing List
> +------------
> +To post a message, send an email to
> +linux-remoteproc@xxxxxxxxxxxxxxx
> diff --git a/Documentation/remoteproc/rproc-api.rst b/Documentation/remoteproc/rproc-api.rst
> new file mode 100644
> index 000000000000..548d3658fc1c
> --- /dev/null
> +++ b/Documentation/remoteproc/rproc-api.rst
> @@ -0,0 +1,75 @@
> +==================================
> +The Linux Remoteproc userspace API
> +==================================
> +
> +Introduction
> +============
> +
> +A Remoteproc (rproc) is a subsystem for managing the lifecycle
> +of a processor that is connected to Linux.
> +
> +At times, userspace may need to check the state of the remote processor to
> +prevent other processes from using it. For instance, if the remote processor
> +is a DSP used for playback, there may be situations where the DSP is
> +undergoing recovery and cannot be used. In such cases, attempts to access the
> +DSP for playback should be blocked. The rproc framework provides sysfs APIs
> +to inform userspace of the processor's current status which should be utilised
> +to achieve the same.
> +
> +Additionally, there are scenarios where userspace applications need to explicitly
> +control the rproc. In these cases, rproc also offers the file descriptors.
> +
> +The simplest API
> +================
> +
> +Below set of api's can be used to start and stop the rproc
> +where 'X' refers to instance of associated remoteproc. There can be systems
> +where there are more than one rprocs such as multiple DSP's
> +connected to application processors running Linux.
> +::
> +   echo start > /sys/class/remoteproc/remoteprocX/state
> +   echo stop > /sys/class/remoteproc/remoteprocX/state
> +
> +To know the state of rproc:
> +
> +.. code-block::
> +
> +   cat /sys/class/remoteproc/remoteprocX/state
> +
> +
> +To dynamically replace firmware, execute the following commands:
> +
> +.. code-block::
> +
> +   echo stop > /sys/class/remoteproc/remoteprocX/state
> +   echo -n <firmware_name> >
> +   /sys/class/remoteproc/remoteprocX/firmware
> +   echo start > /sys/class/remoteproc/remoteprocX/state
> +
> +To simulate a remote crash, execute:
> +
> +.. code-block::
> +
> +   echo 1 > /sys/kernel/debug/remoteproc/remoteprocX/crash
> +
> +To get the trace logs, execute
> +
> +.. code-block::
> +
> +   cat /sys/kernel/debug/remoteproc/remoteprocX/crashX
> +
> +where X will be 0 or 1 if there are 2 resources. Also, this
> +file will only exist if resources are defined in ELF firmware
> +file.
> +
> +The coredump feature can be disabled with the following command:
> +
> +.. code-block::
> +
> +   echo disabled > /sys/kernel/debug/remoteproc/remoteprocX/coredump
> +
> +Userspace can also control start/stop of rproc by using a
> +remoteproc Character Device, it can open the open a file descriptor
> +and write `start` to initiate it, and `stop` to terminate it.
> +
> +[FIXME -- better explanations]
> diff --git a/Documentation/remoteproc/rproc-kernel-api.rst b/Documentation/remoteproc/rproc-kernel-api.rst
> new file mode 100644
> index 000000000000..8604f2b3e6b1
> --- /dev/null
> +++ b/Documentation/remoteproc/rproc-kernel-api.rst
> @@ -0,0 +1,239 @@
> +=====================================================
> +The Linux Remoteproc subsystem Driver Core kernel API
> +=====================================================
> +
> +anish kumar <yesanishhere@xxxxxxxxx>
> +
> +Introduction
> +------------
> +This document does not describe what a Remote processor subsystem
> +(RPROC) Driver or Device is. It also does not describe the API
> +which can be used by user space to communicate with a RPROC driver.
> +If you want to know this then please read the following
> +file: Documentation/remotproc/remoteproc-api.rst .
> +
> +So what does this document describe? It describes the API that can be used by
> +remote processor Drivers that want to use the remote processor Driver Core
> +Framework. This framework provides all interfacing towards user space so that
> +the same code does not have to be reproduced each time. This also means that
> +a remote processor driver then only needs to provide the different routines
> +(operations) that control the remote processor.
> +
> +The API
> +-------
> +Each remote processor driver that wants to use the remote processor Driver Core
> +must #include <linux/remoteproc.h> (you would have to do this anyway when
> +writing a rproc device driver). This include file contains following
> +register routine::
> +
> +	int devm_rproc_add(struct device *dev, struct rproc *rproc)
> +
> +The devm_rproc_add routine registers a remote processor device.
> +The parameter of this routine is a pointer to a rproc device structure.
> +This routine returns zero on success and a negative errno code for failure.
> +
> +The rproc device structure looks like this::
> +
> +  struct rproc {
> +	struct list_head node;
> +	struct iommu_domain *domain;
> +	const char *name;
> +	const char *firmware;
> +	void *priv;
> +	struct rproc_ops *ops;
> +	struct device dev;
> +	atomic_t power;
> +	unsigned int state;
> +	enum rproc_dump_mechanism dump_conf;
> +	struct mutex lock;
> +	struct dentry *dbg_dir;
> +	struct list_head traces;
> +	int num_traces;
> +	struct list_head carveouts;
> +	struct list_head mappings;
> +	u64 bootaddr;
> +	struct list_head rvdevs;
> +	struct list_head subdevs;
> +	struct idr notifyids;
> +	int index;
> +	struct work_struct crash_handler;
> +	unsigned int crash_cnt;
> +	bool recovery_disabled;
> +	int max_notifyid;
> +	struct resource_table *table_ptr;
> +	struct resource_table *clean_table;
> +	struct resource_table *cached_table;
> +	size_t table_sz;
> +	bool has_iommu;
> +	bool auto_boot;
> +	bool sysfs_read_only;
> +	struct list_head dump_segments;
> +	int nb_vdev;
> +	u8 elf_class;
> +	u16 elf_machine;
> +	struct cdev cdev;
> +	bool cdev_put_on_release;
> +	DECLARE_BITMAP(features, RPROC_MAX_FEATURES);
> +  };
> +
> +It contains following fields:
> +
> +* node: list node of this rproc object
> +* domain: iommu domain
> +* name: human readable name of the rproc
> +* firmware: name of firmware file to be loaded
> +* priv: private data which belongs to the platform-specific rproc module
> +* ops: platform-specific start/stop rproc handlers
> +* dev: virtual device for refcounting and common remoteproc behavior
> +* power: refcount of users who need this rproc powered up
> +* state: state of the device
> +* dump_conf: Currently selected coredump configuration
> +* lock: lock which protects concurrent manipulations of the rproc
> +* dbg_dir: debugfs directory of this rproc device
> +* traces: list of trace buffers
> +* num_traces: number of trace buffers
> +* carveouts: list of physically contiguous memory allocations
> +* mappings: list of iommu mappings we initiated, needed on shutdown
> +* bootaddr: address of first instruction to boot rproc with (optional)
> +* rvdevs: list of remote virtio devices
> +* subdevs: list of subdevices, to following the running state
> +* notifyids: idr for dynamically assigning rproc-wide unique notify ids
> +* index: index of this rproc device
> +* crash_handler: workqueue for handling a crash
> +* crash_cnt: crash counter
> +* recovery_disabled: flag that state if recovery was disabled
> +* max_notifyid: largest allocated notify id.
> +* table_ptr: pointer to the resource table in effect
> +* clean_table: copy of the resource table without modifications.  Used
> +*      	 when a remote processor is attached or detached from the core
> +* cached_table: copy of the resource table
> +* table_sz: size of @cached_table
> +* has_iommu: flag to indicate if remote processor is behind an MMU
> +* auto_boot: flag to indicate if remote processor should be auto-started
> +* sysfs_read_only: flag to make remoteproc sysfs files read only
> +* dump_segments: list of segments in the firmware
> +* nb_vdev: number of vdev currently handled by rproc
> +* elf_class: firmware ELF class
> +* elf_machine: firmware ELF machine
> +* cdev: character device of the rproc
> +* cdev_put_on_release: flag to indicate if remoteproc should be shutdown on @char_dev release
> +* features: indicate remoteproc features
> +
> +The list of rproc operations is defined as::
> +
> +  struct rproc_ops {
> +	int (*prepare)(struct rproc *rproc);
> +	int (*unprepare)(struct rproc *rproc);
> +	int (*start)(struct rproc *rproc);
> +	int (*stop)(struct rproc *rproc);
> +	int (*attach)(struct rproc *rproc);
> +	int (*detach)(struct rproc *rproc);
> +	void (*kick)(struct rproc *rproc, int vqid);
> +	void * (*da_to_va)(struct rproc *rproc, u64 da, size_t len, bool *is_iomem);
> +	int (*parse_fw)(struct rproc *rproc, const struct firmware *fw);
> +	int (*handle_rsc)(struct rproc *rproc, u32 rsc_type, void *rsc,
> +			  int offset, int avail);
> +	struct resource_table *(*find_loaded_rsc_table)(
> +				struct rproc *rproc, const struct firmware *fw);
> +	struct resource_table *(*get_loaded_rsc_table)(
> +				struct rproc *rproc, size_t *size);
> +	int (*load)(struct rproc *rproc, const struct firmware *fw);
> +	int (*sanity_check)(struct rproc *rproc, const struct firmware *fw);
> +	u64 (*get_boot_addr)(struct rproc *rproc, const struct firmware *fw);
> +	unsigned long (*panic)(struct rproc *rproc);
> +	void (*coredump)(struct rproc *rproc);
> +  };
> +
> +Most of the operations are optional. Currently in the implementation
> +there are no mandatory operations, however from the practical standpoint
> +minimum ops are:
> +
> +* start: this is a pointer to the routine that starts the remote processor
> +  device.
> +  The routine needs a pointer to the remote processor device structure as a
> +  parameter. It returns zero on success or a negative errno code for failure.
> +
> +* stop: with this routine the remote processor device is being stopped.
> +
> +  The routine needs a pointer to the remote processor device structure as a
> +  parameter. It returns zero on success or a negative errno code for failure.
> +
> +* da_to_va: this is the routine that needs to translate device address to
> +  application processor virtual address that it can copy code to.
> +
> +  The routine needs a pointer to the remote processor device structure as a
> +  parameter. It returns zero on success or a negative errno code for failure.
> +
> +  The routine provides the device address it finds in the ELF firmware and asks
> +  the driver to convert that to virtual address.
> +
> +All other callbacks are optional in case of ELF provided firmware.
> +
> +* load: this is to load the firmware on to the remote device.
> +
> +  The routine needs firmware file that it needs to load on to the remote processor.
> +  If the driver overrides this callback then default ELF loader will not get used.
> +  Otherwise default framework provided loader gets used.
> +
> +  load = rproc_elf_load_segments;
> +  parse_fw = rproc_elf_load_rsc_table;
> +  find_loaded_rsc_table = rproc_elf_find_loaded_rsc_table;
> +  sanity_check = rproc_elf_sanity_check;
> +  get_boot_addr = rproc_elf_get_boot_addr;
> +
> +* parse_fw: this routing parses the provided firmware. In case of ELF format,
> +  framework provided rproc_elf_load_rsc_table function can be used.
> +
> +* sanity_check: Check the format of the firmware.
> +
> +* coredump: If the driver prefers to manage coredumps independently, it can
> +  implement its own coredump handling. However, the framework offers a default
> +  implementation for the ELF format by assigning this callback to
> +  rproc_coredump, unless the driver has overridden it.
> +
> +* get_boot_addr: In case the bootaddr defined in ELF firmware is different, driver
> +  can use this callback to set a different boot address for remote processor to
> +  starts its reset vector from.
> +
> +* find_loaded_rsc_table: this routine gets the loaded resource table from the firmware.
> +
> +  resource table should have a section named (.resource_table) for the framework
> +  to understand and interpret its content. Resource table is a way for remote
> +  processor to ask for resources such as memory for dumping and logging. Look
> +  at core documentation to know how to create the ELF section for the same.
> +
> +* get_loaded_rsc_table: Driver can customize passing the resource table by overriding
> +  this callback. Framework doesn't provide any default implementation for the same.
> +
> +
> +The rproc_report_crash function allows you to report a crash when crash is
> +detected by the driver.
> +
> +::
> +
> +  void rproc_report_crash(struct rproc *rproc, enum rproc_crash_type type);
> +
> +To add a subdev corresponding driver can call::
> +
> +  void rproc_add_subdev(struct rproc *rproc, struct rproc_subdev *subdev);
> +
> +To remove a subdev, driver can call.
> +
> +::
> +
> +  void rproc_remove_subdev(struct rproc *rproc, struct rproc_subdev *subdev);
> +
> +To work with ELF coredump below function can be called::
> +
> +  void rproc_coredump_cleanup(struct rproc *rproc);
> +  void rproc_coredump(struct rproc *rproc);
> +  void rproc_coredump_using_sections(struct rproc *rproc);
> +  int rproc_coredump_add_segment(struct rproc *rproc, dma_addr_t da, size_t size);
> +  int rproc_coredump_add_custom_segment(struct rproc *rproc,
> +                                        dma_addr_t da, size_t size,
> +                                        void (*dumpfn)(struct rproc *rproc,
> +                                           struct rproc_dump_segment *segment,
> +                                           void *dest, size_t offset,
> +                                           size_t size),
> +
> +Remember that coredump functions provided by the framework only works with ELF format.
> diff --git a/Documentation/staging/index.rst b/Documentation/staging/index.rst
> index 77bae5e5328b..d2c2b75fade8 100644
> --- a/Documentation/staging/index.rst
> +++ b/Documentation/staging/index.rst
> @@ -9,7 +9,6 @@ Unsorted Documentation
>     crc32
>     lzo
>     magic-number
> -   remoteproc
>     rpmsg
>     speculation
>     static-keys
> diff --git a/Documentation/staging/remoteproc.rst b/Documentation/staging/remoteproc.rst
> deleted file mode 100644
> index 348ee7e508ac..000000000000
> --- a/Documentation/staging/remoteproc.rst
> +++ /dev/null
> @@ -1,360 +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).
> -
> -::
> -
> -  int 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.
> -
> -Returns 0 on success, and an appropriate error value otherwise.
> -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/Documentation/staging/rpmsg.rst b/Documentation/staging/rpmsg.rst
> index 3713adaa1608..c1eb5343bf37 100644
> --- a/Documentation/staging/rpmsg.rst
> +++ b/Documentation/staging/rpmsg.rst
> @@ -5,7 +5,7 @@ Remote Processor Messaging (rpmsg) Framework
>  .. note::
>  
>    This document describes the rpmsg bus and how to write rpmsg drivers.
> -  To learn how to add rpmsg support for new platforms, check out remoteproc.txt
> +  To learn how to add rpmsg support for new platforms, check out remoteproc
>    (also a resident of Documentation/).
>  
>  Introduction
> -- 
> 2.39.3 (Apple Git-146)
> 
> 




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