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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /drivers/staging/most/Documentation
parentInitial commit. (diff)
downloadlinux-upstream.tar.xz
linux-upstream.zip
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/staging/most/Documentation')
-rw-r--r--drivers/staging/most/Documentation/ABI/sysfs-class-most.txt315
-rw-r--r--drivers/staging/most/Documentation/driver_usage.txt237
2 files changed, 552 insertions, 0 deletions
diff --git a/drivers/staging/most/Documentation/ABI/sysfs-class-most.txt b/drivers/staging/most/Documentation/ABI/sysfs-class-most.txt
new file mode 100644
index 000000000..48aa45acc
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@@ -0,0 +1,315 @@
+What: /sys/class/most/mostcore/aims
+Date: June 2015
+KernelVersion: 4.3
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ List of AIMs that have been loaded.
+Users:
+
+What: /sys/class/most/mostcore/aims/<aim>/add_link
+Date: June 2015
+KernelVersion: 4.3
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ This is used to establish a connection of a channel and the
+ current AIM.
+Users:
+
+What: /sys/class/most/mostcore/aims/<aim>/remove_link
+Date: June 2015
+KernelVersion: 4.3
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ This is used to remove a connected channel from the
+ current AIM.
+Users:
+
+What: /sys/class/most/mostcore/devices
+Date: June 2015
+KernelVersion: 4.3
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ List of attached MOST interfaces.
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/description
+Date: June 2015
+KernelVersion: 4.3
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ Provides information about the interface type and the physical
+ location of the device. Hardware attached via USB, for instance,
+ might return <usb_device 1-1.1:1.0>
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/interface
+Date: June 2015
+KernelVersion: 4.3
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ Indicates the type of peripheral interface the current device
+ uses.
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/dci
+Date: June 2016
+KernelVersion: 4.9
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ If the network interface controller is attached via USB, a dci
+ directory is created that allows applications to use the
+ controller's direct communication interface (DCI) to exchange
+ information.
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/dci/arb_address
+Date: June 2016
+KernelVersion: 4.9
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ This is used to set an arbitrary DCI register address an
+ application wants to read from or write to.
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/dci/arb_value
+Date: June 2016
+KernelVersion: 4.9
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ This is used to read from or write to the arbitrary DCI register
+ whose address is stored in arb_address.
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/dci/mep_eui48_hi
+Date: June 2016
+KernelVersion: 4.9
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ This is used to check and configure the MAC address.
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/dci/mep_eui48_lo
+Date: June 2016
+KernelVersion: 4.9
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ This is used to check and configure the MAC address.
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/dci/mep_eui48_mi
+Date: June 2016
+KernelVersion: 4.9
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ This is used to check and configure the MAC address.
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/dci/mep_filter
+Date: June 2016
+KernelVersion: 4.9
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ This is used to check and configure the MEP filter address.
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/dci/mep_hash0
+Date: June 2016
+KernelVersion: 4.9
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ This is used to check and configure the MEP hash table.
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/dci/mep_hash1
+Date: June 2016
+KernelVersion: 4.9
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ This is used to check and configure the MEP hash table.
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/dci/mep_hash2
+Date: June 2016
+KernelVersion: 4.9
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ This is used to check and configure the MEP hash table.
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/dci/mep_hash3
+Date: June 2016
+KernelVersion: 4.9
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ This is used to check and configure the MEP hash table.
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/dci/ni_state
+Date: June 2016
+KernelVersion: 4.9
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ Indicates the current network interface state.
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/dci/node_address
+Date: June 2016
+KernelVersion: 4.9
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ Indicates the current node address.
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/dci/node_position
+Date: June 2016
+KernelVersion: 4.9
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ Indicates the current node position.
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/dci/packet_bandwidth
+Date: June 2016
+KernelVersion: 4.9
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ Indicates the configured packet bandwidth.
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/dci/sync_ep
+Date: June 2016
+KernelVersion: 4.9
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ Triggers the controller's synchronization process for a certain
+ endpoint.
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/<channel>/
+Date: June 2015
+KernelVersion: 4.3
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ For every channel of the device a directory is created, whose
+ name is dictated by the HDM. This enables an application to
+ collect information about the channel's capabilities and
+ configure it.
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/<channel>/available_datatypes
+Date: June 2015
+KernelVersion: 4.3
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ Indicates the data types the current channel can transport.
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/<channel>/available_directions
+Date: June 2015
+KernelVersion: 4.3
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ Indicates the directions the current channel is capable of.
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/<channel>/number_of_packet_buffers
+Date: June 2015
+KernelVersion: 4.3
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ Indicates the number of packet buffers the current channel can
+ handle.
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/<channel>/number_of_stream_buffers
+Date: June 2015
+KernelVersion: 4.3
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ Indicates the number of streaming buffers the current channel can
+ handle.
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/<channel>/size_of_packet_buffer
+Date: June 2015
+KernelVersion: 4.3
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ Indicates the size of a packet buffer the current channel can
+ handle.
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/<channel>/size_of_stream_buffer
+Date: June 2015
+KernelVersion: 4.3
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ Indicates the size of a streaming buffer the current channel can
+ handle.
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/<channel>/set_number_of_buffers
+Date: June 2015
+KernelVersion: 4.3
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ This is to configure the number of buffers of the current channel.
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/<channel>/set_buffer_size
+Date: June 2015
+KernelVersion: 4.3
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ This is to configure the size of a buffer of the current channel.
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/<channel>/set_direction
+Date: June 2015
+KernelVersion: 4.3
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ This is to configure the direction of the current channel.
+ The following strings will be accepted:
+ 'dir_tx',
+ 'dir_rx'
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/<channel>/set_datatype
+Date: June 2015
+KernelVersion: 4.3
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ This is to configure the data type of the current channel.
+ The following strings will be accepted:
+ 'control',
+ 'async',
+ 'sync',
+ 'isoc_avp'
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/<channel>/set_subbuffer_size
+Date: June 2015
+KernelVersion: 4.3
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ This is to configure the subbuffer size of the current channel.
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/<channel>/set_packets_per_xact
+Date: June 2015
+KernelVersion: 4.3
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ This is to configure the number of packets per transaction of
+ the current channel. This is only needed network interface
+ controller is attached via USB.
+Users:
+
+What: /sys/class/most/mostcore/devices/<mdev>/<channel>/channel_starving
+Date: June 2015
+KernelVersion: 4.3
+Contact: Christian Gromm <christian.gromm@microchip.com>
+Description:
+ Indicates whether current channel ran out of buffers.
+Users:
diff --git a/drivers/staging/most/Documentation/driver_usage.txt b/drivers/staging/most/Documentation/driver_usage.txt
new file mode 100644
index 000000000..2fa8dea1d
--- /dev/null
+++ b/drivers/staging/most/Documentation/driver_usage.txt
@@ -0,0 +1,237 @@
+
+ Section 1 Overview
+
+The Media Oriented Systems Transport (MOST) driver gives Linux applications
+access a MOST network: The Automotive Information Backbone and the de-facto
+standard for high-bandwidth automotive multimedia networking.
+
+MOST defines the protocol, hardware and software layers necessary to allow
+for the efficient and low-cost transport of control, real-time and packet
+data using a single medium (physical layer). Media currently in use are
+fiber optics, unshielded twisted pair cables (UTP) and coax cables. MOST
+also supports various speed grades up to 150 Mbps.
+For more information on MOST, visit the MOST Cooperation website:
+www.mostcooperation.com.
+
+Cars continue to evolve into sophisticated consumer electronics platforms,
+increasing the demand for reliable and simple solutions to support audio,
+video and data communications. MOST can be used to connect multiple
+consumer devices via optical or electrical physical layers directly to one
+another or in a network configuration. As a synchronous network, MOST
+provides excellent Quality of Service and seamless connectivity for
+audio/video streaming. Therefore, the driver perfectly fits to the mission
+of Automotive Grade Linux to create open source software solutions for
+automotive applications.
+
+The MOST driver uses module stacking to divide the associated modules into
+three layers. From bottom up these layers are: the adapter layer, the core
+layer and the application layer. The core layer implements the MOST
+subsystem and consists basically of the module core.c and its API. It
+registers the MOST bus with the kernel's device model, handles the data
+routing through all three layers, the configuration of the driver, the
+representation of the configuration interface in sysfs and the buffer
+management.
+
+For each of the other two layers a set of modules is provided. Those can be
+arbitrarily combined with the core to meet the connectivity of the desired
+system architecture.
+
+A module of the adapter layer is basically a device driver for a different
+subsystem. It is registered with the core to connect the MOST subsystem to
+the attached network interface controller hardware. Hence, a given module
+of this layer is designed to handle exactly one of the peripheral
+interfaces (e.g. USB, MediaLB, I2C) the hardware provides.
+
+A module of the application layer is referred to as a core component,
+which kind of extends the core by providing connectivity to the user space.
+Applications, then, can access a MOST network via character devices, an
+ALSA soundcard, a Network adapter or a V4L2 capture device.
+
+To physically access MOST, an Intelligent Network Interface Controller
+(INIC) is needed. For more information on available controllers visit:
+www.microchip.com
+
+
+
+ Section 1.1 Adapter Layer
+
+The adapter layer contains a pool of device drivers. For each peripheral
+interface the hardware supports there is one suitable module that handles
+the interface. Adapter drivers encapsulate the peripheral interface
+specific knowledge of the MOST driver stack and provide an easy way of
+extending the number of supported interfaces. Currently the following
+interfaces are available:
+
+ 1) MediaLB (DIM2)
+ Host wants to communicate with hardware via MediaLB.
+
+ 2) I2C
+ Host wants to communicate with the hardware via I2C.
+
+ 3) USB
+ Host wants to communicate with the hardware via USB.
+
+Once an adapter driver recognizes a MOST device being attached, it
+registers it with the core, which, in turn, assigns the necessary members
+of the embedded struct device (e.g. the bus this device belongs to and
+attribute groups) and registers it with the kernel's device model.
+
+
+ Section 1.2 Core Layer
+
+This layer implements the MOST subsystem. It contains the core module and
+the header file most.h that exposes the API of the core. When inserted in
+the kernel, it registers the MOST bus_type with the kernel's device model
+and registers itself as a device driver for this bus. Besides these meta
+tasks the core populates the configuration directory for a registered MOST
+device (represented by struct most_interface) in sysfs and processes the
+configuration of the device's interface. The core layer also handles the
+buffer management and the data/message routing.
+
+
+ Section 1.3 Application Layer
+
+This layer contains a pool of device drivers that are components of the
+core designed to make up the userspace experience of the MOST driver stack.
+Depending on how an application is meant to interface the driver, one or
+more modules of this pool can be registered with the core. Currently the
+following components are available
+
+ 1) Character Device
+ Userspace can access the driver by means of character devices.
+
+ 2) Networking
+ Standard networking applications (e.g. iperf) can by used to access
+ the driver via the networking subsystem.
+
+ 3) Video4Linux (v4l2)
+ Standard video applications (e.g. VLC) can by used to access the
+ driver via the V4L subsystem.
+
+ 4) Advanced Linux Sound Architecture (ALSA)
+ Standard sound applications (e.g. aplay, arecord, audacity) can by
+ used to access the driver via the ALSA subsystem.
+
+
+ Section 2 Usage of the MOST Driver
+
+ Section 2.1 Configuration and Data Link
+
+The driver is to be configured via configfs. Each loaded component kernel
+object (see section 1.3) registers a subsystem with configfs, which is used to
+configure and establish communication pathways (links) to attached devices on
+the bus. To do so, the user has to descend into the component's configuration
+directory and create a new directory (child config itmes). The name of this
+directory will be used as a reference for the link and it will contain the
+following attributes:
+
+ - buffer_size
+ configure the buffer size for this channel
+ - subbuffer_size
+ configure the sub-buffer size for this channel (needed for
+ synchronous and isochrnous data)
+ - num_buffers
+ configure number of buffers used for this channel
+ - datatype
+ configure type of data that will travel over this channel
+ - direction
+ configure whether this link will be an input or output
+ - dbr_size
+ configure DBR data buffer size (this is used for MediaLB communication
+ only)
+ - packets_per_xact
+ configure the number of packets that will be collected from the
+ network before being transmitted via USB (this is used for USB
+ communication only)
+ - device
+ name of the device the link is to be attached to
+ - channel
+ name of the channel the link is to be attached to
+ - comp_params
+ pass parameters needed by some components
+ - create_link
+ write '1' to this attribute to trigger the creation of the link. In
+ case of speculative configuration, the creation is post-poned until
+ a physical device is being attached to the bus.
+ - destroy_link
+ write '1' to this attribute to destroy an already established link
+
+
+See ABI/sysfs-bus-most.txt and ABI/configfs-most.txt
+
+
+ Section 2.2 Configure a Sound Card
+
+Setting up synchronous channels to be mapped as an ALSA sound adapter is a two
+step process. Firstly, a directory (child config group) has to be created
+inside the most_sound's configuration directory. This adapter dir will
+represent the sound adapter. The name of the directory is for user reference
+only and has no further influence, as all sound adapters will be given a static
+name in ALSA. The sound adapter will have the following attribute:
+
+ - create_card
+ write '1' to this attribute to trigger the registration of the card
+ with the ALSA subsystem.
+ In case of speculative configuration, the creation is post-poned
+ until a physical device is being attached to the bus.
+
+Secondly, links will have to be created inside the adapter dir as described in
+section 2.1. These links will become the PCM devices of the sound card. The
+name of a PCM device will be inherited from the directory name. When all
+channels have been configured and created, the sound card itself can be created
+by writing '1' to the create_card attribute.
+
+The sound component needs an additional parameter to determine the audio
+resolution that is going to be used.
+The following audio formats are available:
+
+ - "1x8" (Mono)
+ - "2x16" (16-bit stereo)
+ - "2x24" (24-bit stereo)
+ - "2x32" (32-bit stereo)
+ - "6x16" (16-bit surround 5.1)
+
+The resolution string has to be written to the link directory's comp_params
+attribute.
+
+ Section 2.3 USB Padding
+
+When transceiving synchronous or isochronous data, the number of packets
+per USB transaction and the sub-buffer size need to be configured. These
+values are needed for the driver to process buffer padding, as expected by
+hardware, which is for performance optimization purposes of the USB
+transmission.
+
+When transmitting synchronous data the allocated channel width needs to be
+written to 'subbuffer_size'. Additionally, the number of MOST frames that
+should travel to the host within one USB transaction need to be written to
+'packets_per_xact'.
+
+The driver, then, calculates the synchronous threshold as follows:
+
+ frame_size = subbuffer_size * packets_per_xact
+
+In case 'packets_per_xact' is set to 0xFF the maximum number of packets,
+allocated within one MOST frame, is calculated that fit into _one_ 512 byte
+USB full packet.
+
+ frame_size = floor(MTU_USB / bandwidth_sync) * bandwidth_sync
+
+This frame_size is the number of synchronous data within an USB
+transaction, which renders MTU_USB - frame_size bytes for padding.
+
+When transmitting isochronous AVP data the desired packet size needs to be
+written to 'subbuffer_size' and hardware will always expect two isochronous
+packets within one USB transaction. This renders
+
+ MTU_USB - (2 * subbuffer_size)
+
+bytes for padding.
+
+Note that at least (2 * subbuffer_size) bytes for isochronous data or
+(subbuffer_size * packts_per_xact) bytes for synchronous data need to
+be put in the transmission buffer and passed to the driver.
+
+Since adapter drivers are allowed to change a chosen configuration to best
+fit its constraints, it is recommended to always double check the
+configuration and read back the previously written files.