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| -rw-r--r-- | Documentation/misc-devices/ad525x_dpot.rst | 57 | ||||
| -rw-r--r-- | Documentation/misc-devices/apds990x.rst | 128 | ||||
| -rw-r--r-- | Documentation/misc-devices/bh1770glc.rst | 135 | ||||
| -rw-r--r-- | Documentation/misc-devices/c2port.rst | 94 | ||||
| -rw-r--r-- | Documentation/misc-devices/eeprom.rst | 107 | ||||
| -rw-r--r-- | Documentation/misc-devices/ibmvmc.rst | 227 | ||||
| -rw-r--r-- | Documentation/misc-devices/ics932s401.rst | 36 | ||||
| -rw-r--r-- | Documentation/misc-devices/index.rst | 30 | ||||
| -rw-r--r-- | Documentation/misc-devices/isl29003.rst | 75 | ||||
| -rw-r--r-- | Documentation/misc-devices/lis3lv02d.rst | 99 | ||||
| -rw-r--r-- | Documentation/misc-devices/max6875.rst | 136 | ||||
| -rw-r--r-- | Documentation/misc-devices/pci-endpoint-test.rst | 56 | ||||
| -rw-r--r-- | Documentation/misc-devices/spear-pcie-gadget.rst | 170 | ||||
| -rw-r--r-- | Documentation/misc-devices/uacce.rst | 176 | ||||
| -rw-r--r-- | Documentation/misc-devices/xilinx_sdfec.rst | 292 |
15 files changed, 1818 insertions, 0 deletions
diff --git a/Documentation/misc-devices/ad525x_dpot.rst b/Documentation/misc-devices/ad525x_dpot.rst new file mode 100644 index 000000000..6483ec254 --- /dev/null +++ b/Documentation/misc-devices/ad525x_dpot.rst @@ -0,0 +1,57 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============================= +AD525x Digital Potentiometers +============================= + +The ad525x_dpot driver exports a simple sysfs interface. This allows you to +work with the immediate resistance settings as well as update the saved startup +settings. Access to the factory programmed tolerance is also provided, but +interpretation of this settings is required by the end application according to +the specific part in use. + +Files +===== + +Each dpot device will have a set of eeprom, rdac, and tolerance files. How +many depends on the actual part you have, as will the range of allowed values. + +The eeprom files are used to program the startup value of the device. + +The rdac files are used to program the immediate value of the device. + +The tolerance files are the read-only factory programmed tolerance settings +and may vary greatly on a part-by-part basis. For exact interpretation of +this field, please consult the datasheet for your part. This is presented +as a hex file for easier parsing. + +Example +======= + +Locate the device in your sysfs tree. This is probably easiest by going into +the common i2c directory and locating the device by the i2c slave address:: + + # ls /sys/bus/i2c/devices/ + 0-0022 0-0027 0-002f + +So assuming the device in question is on the first i2c bus and has the slave +address of 0x2f, we descend (unrelated sysfs entries have been trimmed):: + + # ls /sys/bus/i2c/devices/0-002f/ + eeprom0 rdac0 tolerance0 + +You can use simple reads/writes to access these files:: + + # cd /sys/bus/i2c/devices/0-002f/ + + # cat eeprom0 + 0 + # echo 10 > eeprom0 + # cat eeprom0 + 10 + + # cat rdac0 + 5 + # echo 3 > rdac0 + # cat rdac0 + 3 diff --git a/Documentation/misc-devices/apds990x.rst b/Documentation/misc-devices/apds990x.rst new file mode 100644 index 000000000..e2f75577f --- /dev/null +++ b/Documentation/misc-devices/apds990x.rst @@ -0,0 +1,128 @@ +.. SPDX-License-Identifier: GPL-2.0 + +====================== +Kernel driver apds990x +====================== + +Supported chips: +Avago APDS990X + +Data sheet: +Not freely available + +Author: +Samu Onkalo <samu.p.onkalo@nokia.com> + +Description +----------- + +APDS990x is a combined ambient light and proximity sensor. ALS and proximity +functionality are highly connected. ALS measurement path must be running +while the proximity functionality is enabled. + +ALS produces raw measurement values for two channels: Clear channel +(infrared + visible light) and IR only. However, threshold comparisons happen +using clear channel only. Lux value and the threshold level on the HW +might vary quite much depending the spectrum of the light source. + +Driver makes necessary conversions to both directions so that user handles +only lux values. Lux value is calculated using information from the both +channels. HW threshold level is calculated from the given lux value to match +with current type of the lightning. Sometimes inaccuracy of the estimations +lead to false interrupt, but that doesn't harm. + +ALS contains 4 different gain steps. Driver automatically +selects suitable gain step. After each measurement, reliability of the results +is estimated and new measurement is triggered if necessary. + +Platform data can provide tuned values to the conversion formulas if +values are known. Otherwise plain sensor default values are used. + +Proximity side is little bit simpler. There is no need for complex conversions. +It produces directly usable values. + +Driver controls chip operational state using pm_runtime framework. +Voltage regulators are controlled based on chip operational state. + +SYSFS +----- + + +chip_id + RO - shows detected chip type and version + +power_state + RW - enable / disable chip. Uses counting logic + + 1 enables the chip + 0 disables the chip +lux0_input + RO - measured lux value + + sysfs_notify called when threshold interrupt occurs + +lux0_sensor_range + RO - lux0_input max value. + + Actually never reaches since sensor tends + to saturate much before that. Real max value varies depending + on the light spectrum etc. + +lux0_rate + RW - measurement rate in Hz + +lux0_rate_avail + RO - supported measurement rates + +lux0_calibscale + RW - calibration value. + + Set to neutral value by default. + Output results are multiplied with calibscale / calibscale_default + value. + +lux0_calibscale_default + RO - neutral calibration value + +lux0_thresh_above_value + RW - HI level threshold value. + + All results above the value + trigs an interrupt. 65535 (i.e. sensor_range) disables the above + interrupt. + +lux0_thresh_below_value + RW - LO level threshold value. + + All results below the value + trigs an interrupt. 0 disables the below interrupt. + +prox0_raw + RO - measured proximity value + + sysfs_notify called when threshold interrupt occurs + +prox0_sensor_range + RO - prox0_raw max value (1023) + +prox0_raw_en + RW - enable / disable proximity - uses counting logic + + - 1 enables the proximity + - 0 disables the proximity + +prox0_reporting_mode + RW - trigger / periodic. + + In "trigger" mode the driver tells two possible + values: 0 or prox0_sensor_range value. 0 means no proximity, + 1023 means proximity. This causes minimal number of interrupts. + In "periodic" mode the driver reports all values above + prox0_thresh_above. This causes more interrupts, but it can give + _rough_ estimate about the distance. + +prox0_reporting_mode_avail + RO - accepted values to prox0_reporting_mode (trigger, periodic) + +prox0_thresh_above_value + RW - threshold level which trigs proximity events. diff --git a/Documentation/misc-devices/bh1770glc.rst b/Documentation/misc-devices/bh1770glc.rst new file mode 100644 index 000000000..ea5ca58bb --- /dev/null +++ b/Documentation/misc-devices/bh1770glc.rst @@ -0,0 +1,135 @@ +.. SPDX-License-Identifier: GPL-2.0 + +======================= +Kernel driver bh1770glc +======================= + +Supported chips: + +- ROHM BH1770GLC +- OSRAM SFH7770 + +Data sheet: +Not freely available + +Author: +Samu Onkalo <samu.p.onkalo@nokia.com> + +Description +----------- +BH1770GLC and SFH7770 are combined ambient light and proximity sensors. +ALS and proximity parts operates on their own, but they shares common I2C +interface and interrupt logic. In principle they can run on their own, +but ALS side results are used to estimate reliability of the proximity sensor. + +ALS produces 16 bit lux values. The chip contains interrupt logic to produce +low and high threshold interrupts. + +Proximity part contains IR-led driver up to 3 IR leds. The chip measures +amount of reflected IR light and produces proximity result. Resolution is +8 bit. Driver supports only one channel. Driver uses ALS results to estimate +reliability of the proximity results. Thus ALS is always running while +proximity detection is needed. + +Driver uses threshold interrupts to avoid need for polling the values. +Proximity low interrupt doesn't exists in the chip. This is simulated +by using a delayed work. As long as there is proximity threshold above +interrupts the delayed work is pushed forward. So, when proximity level goes +below the threshold value, there is no interrupt and the delayed work will +finally run. This is handled as no proximity indication. + +Chip state is controlled via runtime pm framework when enabled in config. + +Calibscale factor is used to hide differences between the chips. By default +value set to neutral state meaning factor of 1.00. To get proper values, +calibrated source of light is needed as a reference. Calibscale factor is set +so that measurement produces about the expected lux value. + +SYSFS +----- + +chip_id + RO - shows detected chip type and version + +power_state + RW - enable / disable chip + + Uses counting logic + + - 1 enables the chip + - 0 disables the chip + +lux0_input + RO - measured lux value + + sysfs_notify called when threshold interrupt occurs + +lux0_sensor_range + RO - lux0_input max value + +lux0_rate + RW - measurement rate in Hz + +lux0_rate_avail + RO - supported measurement rates + +lux0_thresh_above_value + RW - HI level threshold value + + All results above the value + trigs an interrupt. 65535 (i.e. sensor_range) disables the above + interrupt. + +lux0_thresh_below_value + RW - LO level threshold value + + All results below the value + trigs an interrupt. 0 disables the below interrupt. + +lux0_calibscale + RW - calibration value + + Set to neutral value by default. + Output results are multiplied with calibscale / calibscale_default + value. + +lux0_calibscale_default + RO - neutral calibration value + +prox0_raw + RO - measured proximity value + + sysfs_notify called when threshold interrupt occurs + +prox0_sensor_range + RO - prox0_raw max value + +prox0_raw_en + RW - enable / disable proximity + + Uses counting logic + + - 1 enables the proximity + - 0 disables the proximity + +prox0_thresh_above_count + RW - number of proximity interrupts needed before triggering the event + +prox0_rate_above + RW - Measurement rate (in Hz) when the level is above threshold + i.e. when proximity on has been reported. + +prox0_rate_below + RW - Measurement rate (in Hz) when the level is below threshold + i.e. when proximity off has been reported. + +prox0_rate_avail + RO - Supported proximity measurement rates in Hz + +prox0_thresh_above0_value + RW - threshold level which trigs proximity events. + + Filtered by persistence filter (prox0_thresh_above_count) + +prox0_thresh_above1_value + RW - threshold level which trigs event immediately diff --git a/Documentation/misc-devices/c2port.rst b/Documentation/misc-devices/c2port.rst new file mode 100644 index 000000000..7e4f6a794 --- /dev/null +++ b/Documentation/misc-devices/c2port.rst @@ -0,0 +1,94 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. include:: <isonum.txt> + +=============== +C2 port support +=============== + +(C) Copyright 2007 Rodolfo Giometti <giometti@enneenne.com> + +This program is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2 of the License, or +(at your option) any later version. + +This program is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +GNU General Public License for more details. + + + +Overview +-------- + +This driver implements the support for Linux of Silicon Labs (Silabs) +C2 Interface used for in-system programming of micro controllers. + +By using this driver you can reprogram the in-system flash without EC2 +or EC3 debug adapter. This solution is also useful in those systems +where the micro controller is connected via special GPIOs pins. + +References +---------- + +The C2 Interface main references are at (https://www.silabs.com) +Silicon Laboratories site], see: + +- AN127: FLASH Programming via the C2 Interface at + https://www.silabs.com/Support Documents/TechnicalDocs/an127.pdf + +- C2 Specification at + https://www.silabs.com/pages/DownloadDoc.aspx?FILEURL=Support%20Documents/TechnicalDocs/an127.pdf&src=SearchResults + +however it implements a two wire serial communication protocol (bit +banging) designed to enable in-system programming, debugging, and +boundary-scan testing on low pin-count Silicon Labs devices. Currently +this code supports only flash programming but extensions are easy to +add. + +Using the driver +---------------- + +Once the driver is loaded you can use sysfs support to get C2port's +info or read/write in-system flash:: + + # ls /sys/class/c2port/c2port0/ + access flash_block_size flash_erase rev_id + dev_id flash_blocks_num flash_size subsystem/ + flash_access flash_data reset uevent + +Initially the C2port access is disabled since you hardware may have +such lines multiplexed with other devices so, to get access to the +C2port, you need the command:: + + # echo 1 > /sys/class/c2port/c2port0/access + +after that you should read the device ID and revision ID of the +connected micro controller:: + + # cat /sys/class/c2port/c2port0/dev_id + 8 + # cat /sys/class/c2port/c2port0/rev_id + 1 + +However, for security reasons, the in-system flash access in not +enabled yet, to do so you need the command:: + + # echo 1 > /sys/class/c2port/c2port0/flash_access + +After that you can read the whole flash:: + + # cat /sys/class/c2port/c2port0/flash_data > image + +erase it:: + + # echo 1 > /sys/class/c2port/c2port0/flash_erase + +and write it:: + + # cat image > /sys/class/c2port/c2port0/flash_data + +after writing you have to reset the device to execute the new code:: + + # echo 1 > /sys/class/c2port/c2port0/reset diff --git a/Documentation/misc-devices/eeprom.rst b/Documentation/misc-devices/eeprom.rst new file mode 100644 index 000000000..008249675 --- /dev/null +++ b/Documentation/misc-devices/eeprom.rst @@ -0,0 +1,107 @@ +==================== +Kernel driver eeprom +==================== + +Supported chips: + + * Any EEPROM chip in the designated address range + + Prefix: 'eeprom' + + Addresses scanned: I2C 0x50 - 0x57 + + Datasheets: Publicly available from: + + Atmel (www.atmel.com), + Catalyst (www.catsemi.com), + Fairchild (www.fairchildsemi.com), + Microchip (www.microchip.com), + Philips (www.semiconductor.philips.com), + Rohm (www.rohm.com), + ST (www.st.com), + Xicor (www.xicor.com), + and others. + + ========= ============= ============================================ + Chip Size (bits) Address + ========= ============= ============================================ + 24C01 1K 0x50 (shadows at 0x51 - 0x57) + 24C01A 1K 0x50 - 0x57 (Typical device on DIMMs) + 24C02 2K 0x50 - 0x57 + 24C04 4K 0x50, 0x52, 0x54, 0x56 + (additional data at 0x51, 0x53, 0x55, 0x57) + 24C08 8K 0x50, 0x54 (additional data at 0x51, 0x52, + 0x53, 0x55, 0x56, 0x57) + 24C16 16K 0x50 (additional data at 0x51 - 0x57) + Sony 2K 0x57 + + Atmel 34C02B 2K 0x50 - 0x57, SW write protect at 0x30-37 + Catalyst 34FC02 2K 0x50 - 0x57, SW write protect at 0x30-37 + Catalyst 34RC02 2K 0x50 - 0x57, SW write protect at 0x30-37 + Fairchild 34W02 2K 0x50 - 0x57, SW write protect at 0x30-37 + Microchip 24AA52 2K 0x50 - 0x57, SW write protect at 0x30-37 + ST M34C02 2K 0x50 - 0x57, SW write protect at 0x30-37 + ========= ============= ============================================ + + +Authors: + - Frodo Looijaard <frodol@dds.nl>, + - Philip Edelbrock <phil@netroedge.com>, + - Jean Delvare <jdelvare@suse.de>, + - Greg Kroah-Hartman <greg@kroah.com>, + - IBM Corp. + +Description +----------- + +This is a simple EEPROM module meant to enable reading the first 256 bytes +of an EEPROM (on a SDRAM DIMM for example). However, it will access serial +EEPROMs on any I2C adapter. The supported devices are generically called +24Cxx, and are listed above; however the numbering for these +industry-standard devices may vary by manufacturer. + +This module was a programming exercise to get used to the new project +organization laid out by Frodo, but it should be at least completely +effective for decoding the contents of EEPROMs on DIMMs. + +DIMMS will typically contain a 24C01A or 24C02, or the 34C02 variants. +The other devices will not be found on a DIMM because they respond to more +than one address. + +DDC Monitors may contain any device. Often a 24C01, which responds to all 8 +addresses, is found. + +Recent Sony Vaio laptops have an EEPROM at 0x57. We couldn't get the +specification, so it is guess work and far from being complete. + +The Microchip 24AA52/24LCS52, ST M34C02, and others support an additional +software write protect register at 0x30 - 0x37 (0x20 less than the memory +location). The chip responds to "write quick" detection at this address but +does not respond to byte reads. If this register is present, the lower 128 +bytes of the memory array are not write protected. Any byte data write to +this address will write protect the memory array permanently, and the +device will no longer respond at the 0x30-37 address. The eeprom driver +does not support this register. + +Lacking functionality +--------------------- + +* Full support for larger devices (24C04, 24C08, 24C16). These are not + typically found on a PC. These devices will appear as separate devices at + multiple addresses. + +* Support for really large devices (24C32, 24C64, 24C128, 24C256, 24C512). + These devices require two-byte address fields and are not supported. + +* Enable Writing. Again, no technical reason why not, but making it easy + to change the contents of the EEPROMs (on DIMMs anyway) also makes it easy + to disable the DIMMs (potentially preventing the computer from booting) + until the values are restored somehow. + +Use +--- + +After inserting the module (and any other required SMBus/i2c modules), you +should have some EEPROM directories in ``/sys/bus/i2c/devices/*`` of names such +as "0-0050". Inside each of these is a series of files, the eeprom file +contains the binary data from EEPROM. diff --git a/Documentation/misc-devices/ibmvmc.rst b/Documentation/misc-devices/ibmvmc.rst new file mode 100644 index 000000000..b46df4ea2 --- /dev/null +++ b/Documentation/misc-devices/ibmvmc.rst @@ -0,0 +1,227 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +====================================================== +IBM Virtual Management Channel Kernel Driver (IBMVMC) +====================================================== + +:Authors: + Dave Engebretsen <engebret@us.ibm.com>, + Adam Reznechek <adreznec@linux.vnet.ibm.com>, + Steven Royer <seroyer@linux.vnet.ibm.com>, + Bryant G. Ly <bryantly@linux.vnet.ibm.com>, + +Introduction +============ + +Note: Knowledge of virtualization technology is required to understand +this document. + +A good reference document would be: + +https://openpowerfoundation.org/wp-content/uploads/2016/05/LoPAPR_DRAFT_v11_24March2016_cmt1.pdf + +The Virtual Management Channel (VMC) is a logical device which provides an +interface between the hypervisor and a management partition. This interface +is like a message passing interface. This management partition is intended +to provide an alternative to systems that use a Hardware Management +Console (HMC) - based system management. + +The primary hardware management solution that is developed by IBM relies +on an appliance server named the Hardware Management Console (HMC), +packaged as an external tower or rack-mounted personal computer. In a +Power Systems environment, a single HMC can manage multiple POWER +processor-based systems. + +Management Application +---------------------- + +In the management partition, a management application exists which enables +a system administrator to configure the system’s partitioning +characteristics via a command line interface (CLI) or Representational +State Transfer Application (REST API's). + +The management application runs on a Linux logical partition on a +POWER8 or newer processor-based server that is virtualized by PowerVM. +System configuration, maintenance, and control functions which +traditionally require an HMC can be implemented in the management +application using a combination of HMC to hypervisor interfaces and +existing operating system methods. This tool provides a subset of the +functions implemented by the HMC and enables basic partition configuration. +The set of HMC to hypervisor messages supported by the management +application component are passed to the hypervisor over a VMC interface, +which is defined below. + +The VMC enables the management partition to provide basic partitioning +functions: + +- Logical Partitioning Configuration +- Start, and stop actions for individual partitions +- Display of partition status +- Management of virtual Ethernet +- Management of virtual Storage +- Basic system management + +Virtual Management Channel (VMC) +-------------------------------- + +A logical device, called the Virtual Management Channel (VMC), is defined +for communicating between the management application and the hypervisor. It +basically creates the pipes that enable virtualization management +software. This device is presented to a designated management partition as +a virtual device. + +This communication device uses Command/Response Queue (CRQ) and the +Remote Direct Memory Access (RDMA) interfaces. A three-way handshake is +defined that must take place to establish that both the hypervisor and +management partition sides of the channel are running prior to +sending/receiving any of the protocol messages. + +This driver also utilizes Transport Event CRQs. CRQ messages are sent +when the hypervisor detects one of the peer partitions has abnormally +terminated, or one side has called H_FREE_CRQ to close their CRQ. +Two new classes of CRQ messages are introduced for the VMC device. VMC +Administrative messages are used for each partition using the VMC to +communicate capabilities to their partner. HMC Interface messages are used +for the actual flow of HMC messages between the management partition and +the hypervisor. As most HMC messages far exceed the size of a CRQ buffer, +a virtual DMA (RMDA) of the HMC message data is done prior to each HMC +Interface CRQ message. Only the management partition drives RDMA +operations; hypervisors never directly cause the movement of message data. + + +Terminology +----------- +RDMA + Remote Direct Memory Access is DMA transfer from the server to its + client or from the server to its partner partition. DMA refers + to both physical I/O to and from memory operations and to memory + to memory move operations. +CRQ + Command/Response Queue a facility which is used to communicate + between partner partitions. Transport events which are signaled + from the hypervisor to partition are also reported in this queue. + +Example Management Partition VMC Driver Interface +================================================= + +This section provides an example for the management application +implementation where a device driver is used to interface to the VMC +device. This driver consists of a new device, for example /dev/ibmvmc, +which provides interfaces to open, close, read, write, and perform +ioctl’s against the VMC device. + +VMC Interface Initialization +---------------------------- + +The device driver is responsible for initializing the VMC when the driver +is loaded. It first creates and initializes the CRQ. Next, an exchange of +VMC capabilities is performed to indicate the code version and number of +resources available in both the management partition and the hypervisor. +Finally, the hypervisor requests that the management partition create an +initial pool of VMC buffers, one buffer for each possible HMC connection, +which will be used for management application session initialization. +Prior to completion of this initialization sequence, the device returns +EBUSY to open() calls. EIO is returned for all open() failures. + +:: + + Management Partition Hypervisor + CRQ INIT + ----------------------------------------> + CRQ INIT COMPLETE + <---------------------------------------- + CAPABILITIES + ----------------------------------------> + CAPABILITIES RESPONSE + <---------------------------------------- + ADD BUFFER (HMC IDX=0,1,..) _ + <---------------------------------------- | + ADD BUFFER RESPONSE | - Perform # HMCs Iterations + ----------------------------------------> - + +VMC Interface Open +------------------ + +After the basic VMC channel has been initialized, an HMC session level +connection can be established. The application layer performs an open() to +the VMC device and executes an ioctl() against it, indicating the HMC ID +(32 bytes of data) for this session. If the VMC device is in an invalid +state, EIO will be returned for the ioctl(). The device driver creates a +new HMC session value (ranging from 1 to 255) and HMC index value (starting +at index 0 and ranging to 254) for this HMC ID. The driver then does an +RDMA of the HMC ID to the hypervisor, and then sends an Interface Open +message to the hypervisor to establish the session over the VMC. After the +hypervisor receives this information, it sends Add Buffer messages to the +management partition to seed an initial pool of buffers for the new HMC +connection. Finally, the hypervisor sends an Interface Open Response +message, to indicate that it is ready for normal runtime messaging. The +following illustrates this VMC flow: + +:: + + Management Partition Hypervisor + RDMA HMC ID + ----------------------------------------> + Interface Open + ----------------------------------------> + Add Buffer _ + <---------------------------------------- | + Add Buffer Response | - Perform N Iterations + ----------------------------------------> - + Interface Open Response + <---------------------------------------- + +VMC Interface Runtime +--------------------- + +During normal runtime, the management application and the hypervisor +exchange HMC messages via the Signal VMC message and RDMA operations. When +sending data to the hypervisor, the management application performs a +write() to the VMC device, and the driver RDMA’s the data to the hypervisor +and then sends a Signal Message. If a write() is attempted before VMC +device buffers have been made available by the hypervisor, or no buffers +are currently available, EBUSY is returned in response to the write(). A +write() will return EIO for all other errors, such as an invalid device +state. When the hypervisor sends a message to the management, the data is +put into a VMC buffer and an Signal Message is sent to the VMC driver in +the management partition. The driver RDMA’s the buffer into the partition +and passes the data up to the appropriate management application via a +read() to the VMC device. The read() request blocks if there is no buffer +available to read. The management application may use select() to wait for +the VMC device to become ready with data to read. + +:: + + Management Partition Hypervisor + MSG RDMA + ----------------------------------------> + SIGNAL MSG + ----------------------------------------> + SIGNAL MSG + <---------------------------------------- + MSG RDMA + <---------------------------------------- + +VMC Interface Close +------------------- + +HMC session level connections are closed by the management partition when +the application layer performs a close() against the device. This action +results in an Interface Close message flowing to the hypervisor, which +causes the session to be terminated. The device driver must free any +storage allocated for buffers for this HMC connection. + +:: + + Management Partition Hypervisor + INTERFACE CLOSE + ----------------------------------------> + INTERFACE CLOSE RESPONSE + <---------------------------------------- + +Additional Information +====================== + +For more information on the documentation for CRQ Messages, VMC Messages, +HMC interface Buffers, and signal messages please refer to the Linux on +Power Architecture Platform Reference. Section F. diff --git a/Documentation/misc-devices/ics932s401.rst b/Documentation/misc-devices/ics932s401.rst new file mode 100644 index 000000000..613ee54a9 --- /dev/null +++ b/Documentation/misc-devices/ics932s401.rst @@ -0,0 +1,36 @@ +======================== +Kernel driver ics932s401 +======================== + +Supported chips: + + * IDT ICS932S401 + + Prefix: 'ics932s401' + + Addresses scanned: I2C 0x69 + + Datasheet: Publicly available at the IDT website + +Author: Darrick J. Wong + +Description +----------- + +This driver implements support for the IDT ICS932S401 chip family. + +This chip has 4 clock outputs--a base clock for the CPU (which is likely +multiplied to get the real CPU clock), a system clock, a PCI clock, a USB +clock, and a reference clock. The driver reports selected and actual +frequency. If spread spectrum mode is enabled, the driver also reports by what +percent the clock signal is being spread, which should be between 0 and -0.5%. +All frequencies are reported in KHz. + +The ICS932S401 monitors all inputs continuously. The driver will not read +the registers more often than once every other second. + +Special Features +---------------- + +The clocks could be reprogrammed to increase system speed. I will not help you +do this, as you risk damaging your system! diff --git a/Documentation/misc-devices/index.rst b/Documentation/misc-devices/index.rst new file mode 100644 index 000000000..64420b331 --- /dev/null +++ b/Documentation/misc-devices/index.rst @@ -0,0 +1,30 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============================================ +Assorted Miscellaneous Devices Documentation +============================================ + +This documentation contains information for assorted devices that do not +fit into other categories. + +.. class:: toc-title + + Table of contents + +.. toctree:: + :maxdepth: 2 + + ad525x_dpot + apds990x + bh1770glc + eeprom + c2port + ibmvmc + ics932s401 + isl29003 + lis3lv02d + max6875 + pci-endpoint-test + spear-pcie-gadget + uacce + xilinx_sdfec diff --git a/Documentation/misc-devices/isl29003.rst b/Documentation/misc-devices/isl29003.rst new file mode 100644 index 000000000..0cc38aed6 --- /dev/null +++ b/Documentation/misc-devices/isl29003.rst @@ -0,0 +1,75 @@ +====================== +Kernel driver isl29003 +====================== + +Supported chips: + +* Intersil ISL29003 + +Prefix: 'isl29003' + +Addresses scanned: none + +Datasheet: +http://www.intersil.com/data/fn/fn7464.pdf + +Author: Daniel Mack <daniel@caiaq.de> + + +Description +----------- +The ISL29003 is an integrated light sensor with a 16-bit integrating type +ADC, I2C user programmable lux range select for optimized counts/lux, and +I2C multi-function control and monitoring capabilities. The internal ADC +provides 16-bit resolution while rejecting 50Hz and 60Hz flicker caused by +artificial light sources. + +The driver allows to set the lux range, the bit resolution, the operational +mode (see below) and the power state of device and can read the current lux +value, of course. + + +Detection +--------- + +The ISL29003 does not have an ID register which could be used to identify +it, so the detection routine will just try to read from the configured I2C +address and consider the device to be present as soon as it ACKs the +transfer. + + +Sysfs entries +------------- + +range: + == =========================== + 0: 0 lux to 1000 lux (default) + 1: 0 lux to 4000 lux + 2: 0 lux to 16,000 lux + 3: 0 lux to 64,000 lux + == =========================== + +resolution: + == ===================== + 0: 2^16 cycles (default) + 1: 2^12 cycles + 2: 2^8 cycles + 3: 2^4 cycles + == ===================== + +mode: + == ================================================= + 0: diode1's current (unsigned 16bit) (default) + 1: diode1's current (unsigned 16bit) + 2: difference between diodes (l1 - l2, signed 15bit) + == ================================================= + +power_state: + == ================================================= + 0: device is disabled (default) + 1: device is enabled + == ================================================= + +lux (read only): + returns the value from the last sensor reading + diff --git a/Documentation/misc-devices/lis3lv02d.rst b/Documentation/misc-devices/lis3lv02d.rst new file mode 100644 index 000000000..959bd2b82 --- /dev/null +++ b/Documentation/misc-devices/lis3lv02d.rst @@ -0,0 +1,99 @@ +======================= +Kernel driver lis3lv02d +======================= + +Supported chips: + + * STMicroelectronics LIS3LV02DL, LIS3LV02DQ (12 bits precision) + * STMicroelectronics LIS302DL, LIS3L02DQ, LIS331DL (8 bits) and + LIS331DLH (16 bits) + +Authors: + - Yan Burman <burman.yan@gmail.com> + - Eric Piel <eric.piel@tremplin-utc.net> + + +Description +----------- + +This driver provides support for the accelerometer found in various HP laptops +sporting the feature officially called "HP Mobile Data Protection System 3D" or +"HP 3D DriveGuard". It detects automatically laptops with this sensor. Known +models (full list can be found in drivers/platform/x86/hp_accel.c) will have +their axis automatically oriented on standard way (eg: you can directly play +neverball). The accelerometer data is readable via +/sys/devices/platform/lis3lv02d. Reported values are scaled +to mg values (1/1000th of earth gravity). + +Sysfs attributes under /sys/devices/platform/lis3lv02d/: + +position + - 3D position that the accelerometer reports. Format: "(x,y,z)" +rate + - read reports the sampling rate of the accelerometer device in HZ. + write changes sampling rate of the accelerometer device. + Only values which are supported by HW are accepted. +selftest + - performs selftest for the chip as specified by chip manufacturer. + +This driver also provides an absolute input class device, allowing +the laptop to act as a pinball machine-esque joystick. Joystick device can be +calibrated. Joystick device can be in two different modes. +By default output values are scaled between -32768 .. 32767. In joystick raw +mode, joystick and sysfs position entry have the same scale. There can be +small difference due to input system fuzziness feature. +Events are also available as input event device. + +Selftest is meant only for hardware diagnostic purposes. It is not meant to be +used during normal operations. Position data is not corrupted during selftest +but interrupt behaviour is not guaranteed to work reliably. In test mode, the +sensing element is internally moved little bit. Selftest measures difference +between normal mode and test mode. Chip specifications tell the acceptance +limit for each type of the chip. Limits are provided via platform data +to allow adjustment of the limits without a change to the actual driver. +Seltest returns either "OK x y z" or "FAIL x y z" where x, y and z are +measured difference between modes. Axes are not remapped in selftest mode. +Measurement values are provided to help HW diagnostic applications to make +final decision. + +On HP laptops, if the led infrastructure is activated, support for a led +indicating disk protection will be provided as /sys/class/leds/hp::hddprotect. + +Another feature of the driver is misc device called "freefall" that +acts similar to /dev/rtc and reacts on free-fall interrupts received +from the device. It supports blocking operations, poll/select and +fasync operation modes. You must read 1 bytes from the device. The +result is number of free-fall interrupts since the last successful +read (or 255 if number of interrupts would not fit). See the freefall.c +file for an example on using the device. + + +Axes orientation +---------------- + +For better compatibility between the various laptops. The values reported by +the accelerometer are converted into a "standard" organisation of the axes +(aka "can play neverball out of the box"): + + * When the laptop is horizontal the position reported is about 0 for X and Y + and a positive value for Z + * If the left side is elevated, X increases (becomes positive) + * If the front side (where the touchpad is) is elevated, Y decreases + (becomes negative) + * If the laptop is put upside-down, Z becomes negative + +If your laptop model is not recognized (cf "dmesg"), you can send an +email to the maintainer to add it to the database. When reporting a new +laptop, please include the output of "dmidecode" plus the value of +/sys/devices/platform/lis3lv02d/position in these four cases. + +Q&A +--- + +Q: How do I safely simulate freefall? I have an HP "portable +workstation" which has about 3.5kg and a plastic case, so letting it +fall to the ground is out of question... + +A: The sensor is pretty sensitive, so your hands can do it. Lift it +into free space, follow the fall with your hands for like 10 +centimeters. That should be enough to trigger the detection. diff --git a/Documentation/misc-devices/max6875.rst b/Documentation/misc-devices/max6875.rst new file mode 100644 index 000000000..ad419ac22 --- /dev/null +++ b/Documentation/misc-devices/max6875.rst @@ -0,0 +1,136 @@ +===================== +Kernel driver max6875 +===================== + +Supported chips: + + * Maxim MAX6874, MAX6875 + + Prefix: 'max6875' + + Addresses scanned: None (see below) + + Datasheet: http://pdfserv.maxim-ic.com/en/ds/MAX6874-MAX6875.pdf + +Author: Ben Gardner <bgardner@wabtec.com> + + +Description +----------- + +The Maxim MAX6875 is an EEPROM-programmable power-supply sequencer/supervisor. +It provides timed outputs that can be used as a watchdog, if properly wired. +It also provides 512 bytes of user EEPROM. + +At reset, the MAX6875 reads the configuration EEPROM into its configuration +registers. The chip then begins to operate according to the values in the +registers. + +The Maxim MAX6874 is a similar, mostly compatible device, with more inputs +and outputs: + +=========== === === ==== +- vin gpi vout +=========== === === ==== +MAX6874 6 4 8 +MAX6875 4 3 5 +=========== === === ==== + +See the datasheet for more information. + + +Sysfs entries +------------- + +eeprom - 512 bytes of user-defined EEPROM space. + + +General Remarks +--------------- + +Valid addresses for the MAX6875 are 0x50 and 0x52. + +Valid addresses for the MAX6874 are 0x50, 0x52, 0x54 and 0x56. + +The driver does not probe any address, so you explicitly instantiate the +devices. + +Example:: + + $ modprobe max6875 + $ echo max6875 0x50 > /sys/bus/i2c/devices/i2c-0/new_device + +The MAX6874/MAX6875 ignores address bit 0, so this driver attaches to multiple +addresses. For example, for address 0x50, it also reserves 0x51. +The even-address instance is called 'max6875', the odd one is 'dummy'. + + +Programming the chip using i2c-dev +---------------------------------- + +Use the i2c-dev interface to access and program the chips. + +Reads and writes are performed differently depending on the address range. + +The configuration registers are at addresses 0x00 - 0x45. + +Use i2c_smbus_write_byte_data() to write a register and +i2c_smbus_read_byte_data() to read a register. + +The command is the register number. + +Examples: + +To write a 1 to register 0x45:: + + i2c_smbus_write_byte_data(fd, 0x45, 1); + +To read register 0x45:: + + value = i2c_smbus_read_byte_data(fd, 0x45); + + +The configuration EEPROM is at addresses 0x8000 - 0x8045. + +The user EEPROM is at addresses 0x8100 - 0x82ff. + +Use i2c_smbus_write_word_data() to write a byte to EEPROM. + +The command is the upper byte of the address: 0x80, 0x81, or 0x82. +The data word is the lower part of the address or'd with data << 8:: + + cmd = address >> 8; + val = (address & 0xff) | (data << 8); + +Example: + +To write 0x5a to address 0x8003:: + + i2c_smbus_write_word_data(fd, 0x80, 0x5a03); + + +Reading data from the EEPROM is a little more complicated. + +Use i2c_smbus_write_byte_data() to set the read address and then +i2c_smbus_read_byte() or i2c_smbus_read_i2c_block_data() to read the data. + +Example: + +To read data starting at offset 0x8100, first set the address:: + + i2c_smbus_write_byte_data(fd, 0x81, 0x00); + +And then read the data:: + + value = i2c_smbus_read_byte(fd); + +or:: + + count = i2c_smbus_read_i2c_block_data(fd, 0x84, 16, buffer); + +The block read should read 16 bytes. + +0x84 is the block read command. + +See the datasheet for more details. + diff --git a/Documentation/misc-devices/pci-endpoint-test.rst b/Documentation/misc-devices/pci-endpoint-test.rst new file mode 100644 index 000000000..4cf3f4433 --- /dev/null +++ b/Documentation/misc-devices/pci-endpoint-test.rst @@ -0,0 +1,56 @@ +.. SPDX-License-Identifier: GPL-2.0 + +===================================== +Driver for PCI Endpoint Test Function +===================================== + +This driver should be used as a host side driver if the root complex is +connected to a configurable PCI endpoint running ``pci_epf_test`` function +driver configured according to [1]_. + +The "pci_endpoint_test" driver can be used to perform the following tests. + +The PCI driver for the test device performs the following tests: + + #) verifying addresses programmed in BAR + #) raise legacy IRQ + #) raise MSI IRQ + #) raise MSI-X IRQ + #) read data + #) write data + #) copy data + +This misc driver creates /dev/pci-endpoint-test.<num> for every +``pci_epf_test`` function connected to the root complex and "ioctls" +should be used to perform the above tests. + +ioctl +----- + + PCITEST_BAR: + Tests the BAR. The number of the BAR to be tested + should be passed as argument. + PCITEST_LEGACY_IRQ: + Tests legacy IRQ + PCITEST_MSI: + Tests message signalled interrupts. The MSI number + to be tested should be passed as argument. + PCITEST_MSIX: + Tests message signalled interrupts. The MSI-X number + to be tested should be passed as argument. + PCITEST_SET_IRQTYPE: + Changes driver IRQ type configuration. The IRQ type + should be passed as argument (0: Legacy, 1:MSI, 2:MSI-X). + PCITEST_GET_IRQTYPE: + Gets driver IRQ type configuration. + PCITEST_WRITE: + Perform write tests. The size of the buffer should be passed + as argument. + PCITEST_READ: + Perform read tests. The size of the buffer should be passed + as argument. + PCITEST_COPY: + Perform read tests. The size of the buffer should be passed + as argument. + +.. [1] Documentation/PCI/endpoint/function/binding/pci-test.rst diff --git a/Documentation/misc-devices/spear-pcie-gadget.rst b/Documentation/misc-devices/spear-pcie-gadget.rst new file mode 100644 index 000000000..09b9d6c7a --- /dev/null +++ b/Documentation/misc-devices/spear-pcie-gadget.rst @@ -0,0 +1,170 @@ +.. SPDX-License-Identifier: GPL-2.0 + +======================== +Spear PCIe Gadget Driver +======================== + +Author +====== +Pratyush Anand (pratyush.anand@gmail.com) + +Location +======== +driver/misc/spear13xx_pcie_gadget.c + +Supported Chip: +=============== +SPEAr1300 +SPEAr1310 + +Menuconfig option: +================== +Device Drivers + Misc devices + PCIe gadget support for SPEAr13XX platform + +purpose +======= +This driver has several nodes which can be read/written by configfs interface. +Its main purpose is to configure selected dual mode PCIe controller as device +and then program its various registers to configure it as a particular device +type. This driver can be used to show spear's PCIe device capability. + +Description of different nodes: +=============================== + +read behavior of nodes: +----------------------- + +=============== ============================================================== +link gives ltssm status. +int_type type of supported interrupt +no_of_msi zero if MSI is not enabled by host. A positive value is the + number of MSI vector granted. +vendor_id returns programmed vendor id (hex) +device_id returns programmed device id(hex) +bar0_size: returns size of bar0 in hex. +bar0_address returns address of bar0 mapped area in hex. +bar0_rw_offset returns offset of bar0 for which bar0_data will return value. +bar0_data returns data at bar0_rw_offset. +=============== ============================================================== + +write behavior of nodes: +------------------------ + +=============== ================================================================ +link write UP to enable ltsmm DOWN to disable +int_type write interrupt type to be configured and (int_type could be + INTA, MSI or NO_INT). Select MSI only when you have programmed + no_of_msi node. +no_of_msi number of MSI vector needed. +inta write 1 to assert INTA and 0 to de-assert. +send_msi write MSI vector to be sent. +vendor_id write vendor id(hex) to be programmed. +device_id write device id(hex) to be programmed. +bar0_size write size of bar0 in hex. default bar0 size is 1000 (hex) + bytes. +bar0_address write address of bar0 mapped area in hex. (default mapping of + bar0 is SYSRAM1(E0800000). Always program bar size before bar + address. Kernel might modify bar size and address for alignment, + so read back bar size and address after writing to cross check. +bar0_rw_offset write offset of bar0 for which bar0_data will write value. +bar0_data write data to be written at bar0_rw_offset. +=============== ================================================================ + +Node programming example +======================== + +Program all PCIe registers in such a way that when this device is connected +to the PCIe host, then host sees this device as 1MB RAM. + +:: + + #mount -t configfs none /Config + +For nth PCIe Device Controller:: + + # cd /config/pcie_gadget.n/ + +Now you have all the nodes in this directory. +program vendor id as 0x104a:: + + # echo 104A >> vendor_id + +program device id as 0xCD80:: + + # echo CD80 >> device_id + +program BAR0 size as 1MB:: + + # echo 100000 >> bar0_size + +check for programmed bar0 size:: + + # cat bar0_size + +Program BAR0 Address as DDR (0x2100000). This is the physical address of +memory, which is to be made visible to PCIe host. Similarly any other peripheral +can also be made visible to PCIe host. E.g., if you program base address of UART +as BAR0 address then when this device will be connected to a host, it will be +visible as UART. + +:: + + # echo 2100000 >> bar0_address + +program interrupt type : INTA:: + + # echo INTA >> int_type + +go for link up now:: + + # echo UP >> link + +It will have to be insured that, once link up is done on gadget, then only host +is initialized and start to search PCIe devices on its port. + +:: + + /*wait till link is up*/ + # cat link + +Wait till it returns UP. + +To assert INTA:: + + # echo 1 >> inta + +To de-assert INTA:: + + # echo 0 >> inta + +if MSI is to be used as interrupt, program no of msi vector needed (say4):: + + # echo 4 >> no_of_msi + +select MSI as interrupt type:: + + # echo MSI >> int_type + +go for link up now:: + + # echo UP >> link + +wait till link is up:: + + # cat link + +An application can repetitively read this node till link is found UP. It can +sleep between two read. + +wait till msi is enabled:: + + # cat no_of_msi + +Should return 4 (number of requested MSI vector) + +to send msi vector 2:: + + # echo 2 >> send_msi + # cd - diff --git a/Documentation/misc-devices/uacce.rst b/Documentation/misc-devices/uacce.rst new file mode 100644 index 000000000..1db412e9b --- /dev/null +++ b/Documentation/misc-devices/uacce.rst @@ -0,0 +1,176 @@ +.. SPDX-License-Identifier: GPL-2.0 + +Introduction of Uacce +--------------------- + +Uacce (Unified/User-space-access-intended Accelerator Framework) targets to +provide Shared Virtual Addressing (SVA) between accelerators and processes. +So accelerator can access any data structure of the main cpu. +This differs from the data sharing between cpu and io device, which share +only data content rather than address. +Because of the unified address, hardware and user space of process can +share the same virtual address in the communication. +Uacce takes the hardware accelerator as a heterogeneous processor, while +IOMMU share the same CPU page tables and as a result the same translation +from va to pa. + +:: + + __________________________ __________________________ + | | | | + | User application (CPU) | | Hardware Accelerator | + |__________________________| |__________________________| + + | | + | va | va + V V + __________ __________ + | | | | + | MMU | | IOMMU | + |__________| |__________| + | | + | | + V pa V pa + _______________________________________ + | | + | Memory | + |_______________________________________| + + + +Architecture +------------ + +Uacce is the kernel module, taking charge of iommu and address sharing. +The user drivers and libraries are called WarpDrive. + +The uacce device, built around the IOMMU SVA API, can access multiple +address spaces, including the one without PASID. + +A virtual concept, queue, is used for the communication. It provides a +FIFO-like interface. And it maintains a unified address space between the +application and all involved hardware. + +:: + + ___________________ ________________ + | | user API | | + | WarpDrive library | ------------> | user driver | + |___________________| |________________| + | | + | | + | queue fd | + | | + | | + v | + ___________________ _________ | + | | | | | mmap memory + | Other framework | | uacce | | r/w interface + | crypto/nic/others | |_________| | + |___________________| | + | | | + | register | register | + | | | + | | | + | _________________ __________ | + | | | | | | + ------------- | Device Driver | | IOMMU | | + |_________________| |__________| | + | | + | V + | ___________________ + | | | + -------------------------- | Device(Hardware) | + |___________________| + + +How does it work +---------------- + +Uacce uses mmap and IOMMU to play the trick. + +Uacce creates a chrdev for every device registered to it. New queue is +created when user application open the chrdev. The file descriptor is used +as the user handle of the queue. +The accelerator device present itself as an Uacce object, which exports as +a chrdev to the user space. The user application communicates with the +hardware by ioctl (as control path) or share memory (as data path). + +The control path to the hardware is via file operation, while data path is +via mmap space of the queue fd. + +The queue file address space: + +:: + + /** + * enum uacce_qfrt: qfrt type + * @UACCE_QFRT_MMIO: device mmio region + * @UACCE_QFRT_DUS: device user share region + */ + enum uacce_qfrt { + UACCE_QFRT_MMIO = 0, + UACCE_QFRT_DUS = 1, + }; + +All regions are optional and differ from device type to type. +Each region can be mmapped only once, otherwise -EEXIST returns. + +The device mmio region is mapped to the hardware mmio space. It is generally +used for doorbell or other notification to the hardware. It is not fast enough +as data channel. + +The device user share region is used for share data buffer between user process +and device. + + +The Uacce register API +---------------------- + +The register API is defined in uacce.h. + +:: + + struct uacce_interface { + char name[UACCE_MAX_NAME_SIZE]; + unsigned int flags; + const struct uacce_ops *ops; + }; + +According to the IOMMU capability, uacce_interface flags can be: + +:: + + /** + * UACCE Device flags: + * UACCE_DEV_SVA: Shared Virtual Addresses + * Support PASID + * Support device page faults (PCI PRI or SMMU Stall) + */ + #define UACCE_DEV_SVA BIT(0) + + struct uacce_device *uacce_alloc(struct device *parent, + struct uacce_interface *interface); + int uacce_register(struct uacce_device *uacce); + void uacce_remove(struct uacce_device *uacce); + +uacce_register results can be: + +a. If uacce module is not compiled, ERR_PTR(-ENODEV) + +b. Succeed with the desired flags + +c. Succeed with the negotiated flags, for example + + uacce_interface.flags = UACCE_DEV_SVA but uacce->flags = ~UACCE_DEV_SVA + + So user driver need check return value as well as the negotiated uacce->flags. + + +The user driver +--------------- + +The queue file mmap space will need a user driver to wrap the communication +protocol. Uacce provides some attributes in sysfs for the user driver to +match the right accelerator accordingly. +More details in Documentation/ABI/testing/sysfs-driver-uacce. diff --git a/Documentation/misc-devices/xilinx_sdfec.rst b/Documentation/misc-devices/xilinx_sdfec.rst new file mode 100644 index 000000000..8c8a289d6 --- /dev/null +++ b/Documentation/misc-devices/xilinx_sdfec.rst @@ -0,0 +1,292 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +==================== +Xilinx SD-FEC Driver +==================== + +Overview +======== + +This driver supports SD-FEC Integrated Block for Zynq |Ultrascale+ (TM)| RFSoCs. + +.. |Ultrascale+ (TM)| unicode:: Ultrascale+ U+2122 + .. with trademark sign + +For a full description of SD-FEC core features, see the `SD-FEC Product Guide (PG256) <https://www.xilinx.com/cgi-bin/docs/ipdoc?c=sd_fec;v=latest;d=pg256-sdfec-integrated-block.pdf>`_ + +This driver supports the following features: + + - Retrieval of the Integrated Block configuration and status information + - Configuration of LDPC codes + - Configuration of Turbo decoding + - Monitoring errors + +Missing features, known issues, and limitations of the SD-FEC driver are as +follows: + + - Only allows a single open file handler to any instance of the driver at any time + - Reset of the SD-FEC Integrated Block is not controlled by this driver + - Does not support shared LDPC code table wraparound + +The device tree entry is described in: +`linux-xlnx/Documentation/devicetree/bindings/misc/xlnx,sd-fec.txt <https://github.com/Xilinx/linux-xlnx/blob/master/Documentation/devicetree/bindings/misc/xlnx%2Csd-fec.txt>`_ + + +Modes of Operation +------------------ + +The driver works with the SD-FEC core in two modes of operation: + + - Run-time configuration + - Programmable Logic (PL) initialization + + +Run-time Configuration +~~~~~~~~~~~~~~~~~~~~~~ + +For Run-time configuration the role of driver is to allow the software application to do the following: + + - Load the configuration parameters for either Turbo decode or LDPC encode or decode + - Activate the SD-FEC core + - Monitor the SD-FEC core for errors + - Retrieve the status and configuration of the SD-FEC core + +Programmable Logic (PL) Initialization +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +For PL initialization, supporting logic loads configuration parameters for either +the Turbo decode or LDPC encode or decode. The role of the driver is to allow +the software application to do the following: + + - Activate the SD-FEC core + - Monitor the SD-FEC core for errors + - Retrieve the status and configuration of the SD-FEC core + + +Driver Structure +================ + +The driver provides a platform device where the ``probe`` and ``remove`` +operations are provided. + + - probe: Updates configuration register with device-tree entries plus determines the current activate state of the core, for example, is the core bypassed or has the core been started. + + +The driver defines the following driver file operations to provide user +application interfaces: + + - open: Implements restriction that only a single file descriptor can be open per SD-FEC instance at any time + - release: Allows another file descriptor to be open, that is after current file descriptor is closed + - poll: Provides a method to monitor for SD-FEC Error events + - unlocked_ioctl: Provides the following ioctl commands that allows the application configure the SD-FEC core: + + - :c:macro:`XSDFEC_START_DEV` + - :c:macro:`XSDFEC_STOP_DEV` + - :c:macro:`XSDFEC_GET_STATUS` + - :c:macro:`XSDFEC_SET_IRQ` + - :c:macro:`XSDFEC_SET_TURBO` + - :c:macro:`XSDFEC_ADD_LDPC_CODE_PARAMS` + - :c:macro:`XSDFEC_GET_CONFIG` + - :c:macro:`XSDFEC_SET_ORDER` + - :c:macro:`XSDFEC_SET_BYPASS` + - :c:macro:`XSDFEC_IS_ACTIVE` + - :c:macro:`XSDFEC_CLEAR_STATS` + - :c:macro:`XSDFEC_SET_DEFAULT_CONFIG` + + +Driver Usage +============ + + +Overview +-------- + +After opening the driver, the user should find out what operations need to be +performed to configure and activate the SD-FEC core and determine the +configuration of the driver. +The following outlines the flow the user should perform: + + - Determine Configuration + - Set the order, if not already configured as desired + - Set Turbo decode, LPDC encode or decode parameters, depending on how the + SD-FEC core is configured plus if the SD-FEC has not been configured for PL + initialization + - Enable interrupts, if not already enabled + - Bypass the SD-FEC core, if required + - Start the SD-FEC core if not already started + - Get the SD-FEC core status + - Monitor for interrupts + - Stop the SD-FEC core + + +Note: When monitoring for interrupts if a critical error is detected where a reset is required, the driver will be required to load the default configuration. + + +Determine Configuration +----------------------- + +Determine the configuration of the SD-FEC core by using the ioctl +:c:macro:`XSDFEC_GET_CONFIG`. + +Set the Order +------------- + +Setting the order determines how the order of Blocks can change from input to output. + +Setting the order is done by using the ioctl :c:macro:`XSDFEC_SET_ORDER` + +Setting the order can only be done if the following restrictions are met: + + - The ``state`` member of struct :c:type:`xsdfec_status <xsdfec_status>` filled by the ioctl :c:macro:`XSDFEC_GET_STATUS` indicates the SD-FEC core has not STARTED + + +Add LDPC Codes +-------------- + +The following steps indicate how to add LDPC codes to the SD-FEC core: + + - Use the auto-generated parameters to fill the :c:type:`struct xsdfec_ldpc_params <xsdfec_ldpc_params>` for the desired LDPC code. + - Set the SC, QA, and LA table offsets for the LPDC parameters and the parameters in the structure :c:type:`struct xsdfec_ldpc_params <xsdfec_ldpc_params>` + - Set the desired Code Id value in the structure :c:type:`struct xsdfec_ldpc_params <xsdfec_ldpc_params>` + - Add the LPDC Code Parameters using the ioctl :c:macro:`XSDFEC_ADD_LDPC_CODE_PARAMS` + - For the applied LPDC Code Parameter use the function :c:func:`xsdfec_calculate_shared_ldpc_table_entry_size` to calculate the size of shared LPDC code tables. This allows the user to determine the shared table usage so when selecting the table offsets for the next LDPC code parameters unused table areas can be selected. + - Repeat for each LDPC code parameter. + +Adding LDPC codes can only be done if the following restrictions are met: + + - The ``code`` member of :c:type:`struct xsdfec_config <xsdfec_config>` filled by the ioctl :c:macro:`XSDFEC_GET_CONFIG` indicates the SD-FEC core is configured as LDPC + - The ``code_wr_protect`` of :c:type:`struct xsdfec_config <xsdfec_config>` filled by the ioctl :c:macro:`XSDFEC_GET_CONFIG` indicates that write protection is not enabled + - The ``state`` member of struct :c:type:`xsdfec_status <xsdfec_status>` filled by the ioctl :c:macro:`XSDFEC_GET_STATUS` indicates the SD-FEC core has not started + +Set Turbo Decode +---------------- + +Configuring the Turbo decode parameters is done by using the ioctl :c:macro:`XSDFEC_SET_TURBO` using auto-generated parameters to fill the :c:type:`struct xsdfec_turbo <xsdfec_turbo>` for the desired Turbo code. + +Adding Turbo decode can only be done if the following restrictions are met: + + - The ``code`` member of :c:type:`struct xsdfec_config <xsdfec_config>` filled by the ioctl :c:macro:`XSDFEC_GET_CONFIG` indicates the SD-FEC core is configured as TURBO + - The ``state`` member of struct :c:type:`xsdfec_status <xsdfec_status>` filled by the ioctl :c:macro:`XSDFEC_GET_STATUS` indicates the SD-FEC core has not STARTED + +Enable Interrupts +----------------- + +Enabling or disabling interrupts is done by using the ioctl :c:macro:`XSDFEC_SET_IRQ`. The members of the parameter passed, :c:type:`struct xsdfec_irq <xsdfec_irq>`, to the ioctl are used to set and clear different categories of interrupts. The category of interrupt is controlled as following: + + - ``enable_isr`` controls the ``tlast`` interrupts + - ``enable_ecc_isr`` controls the ECC interrupts + +If the ``code`` member of :c:type:`struct xsdfec_config <xsdfec_config>` filled by the ioctl :c:macro:`XSDFEC_GET_CONFIG` indicates the SD-FEC core is configured as TURBO then the enabling ECC errors is not required. + +Bypass the SD-FEC +----------------- + +Bypassing the SD-FEC is done by using the ioctl :c:macro:`XSDFEC_SET_BYPASS` + +Bypassing the SD-FEC can only be done if the following restrictions are met: + + - The ``state`` member of :c:type:`struct xsdfec_status <xsdfec_status>` filled by the ioctl :c:macro:`XSDFEC_GET_STATUS` indicates the SD-FEC core has not STARTED + +Start the SD-FEC core +--------------------- + +Start the SD-FEC core by using the ioctl :c:macro:`XSDFEC_START_DEV` + +Get SD-FEC Status +----------------- + +Get the SD-FEC status of the device by using the ioctl :c:macro:`XSDFEC_GET_STATUS`, which will fill the :c:type:`struct xsdfec_status <xsdfec_status>` + +Monitor for Interrupts +---------------------- + + - Use the poll system call to monitor for an interrupt. The poll system call waits for an interrupt to wake it up or times out if no interrupt occurs. + - On return Poll ``revents`` will indicate whether stats and/or state have been updated + - ``POLLPRI`` indicates a critical error and the user should use :c:macro:`XSDFEC_GET_STATUS` and :c:macro:`XSDFEC_GET_STATS` to confirm + - ``POLLRDNORM`` indicates a non-critical error has occurred and the user should use :c:macro:`XSDFEC_GET_STATS` to confirm + - Get stats by using the ioctl :c:macro:`XSDFEC_GET_STATS` + - For critical error the ``isr_err_count`` or ``uecc_count`` member of :c:type:`struct xsdfec_stats <xsdfec_stats>` is non-zero + - For non-critical errors the ``cecc_count`` member of :c:type:`struct xsdfec_stats <xsdfec_stats>` is non-zero + - Get state by using the ioctl :c:macro:`XSDFEC_GET_STATUS` + - For a critical error the ``state`` of :c:type:`xsdfec_status <xsdfec_status>` will indicate a Reset Is Required + - Clear stats by using the ioctl :c:macro:`XSDFEC_CLEAR_STATS` + +If a critical error is detected where a reset is required. The application is required to call the ioctl :c:macro:`XSDFEC_SET_DEFAULT_CONFIG`, after the reset and it is not required to call the ioctl :c:macro:`XSDFEC_STOP_DEV` + +Note: Using poll system call prevents busy looping using :c:macro:`XSDFEC_GET_STATS` and :c:macro:`XSDFEC_GET_STATUS` + +Stop the SD-FEC Core +--------------------- + +Stop the device by using the ioctl :c:macro:`XSDFEC_STOP_DEV` + +Set the Default Configuration +----------------------------- + +Load default configuration by using the ioctl :c:macro:`XSDFEC_SET_DEFAULT_CONFIG` to restore the driver. + +Limitations +----------- + +Users should not duplicate SD-FEC device file handlers, for example fork() or dup() a process that has a created an SD-FEC file handler. + +Driver IOCTLs +============== + +.. c:macro:: XSDFEC_START_DEV +.. kernel-doc:: include/uapi/misc/xilinx_sdfec.h + :doc: XSDFEC_START_DEV + +.. c:macro:: XSDFEC_STOP_DEV +.. kernel-doc:: include/uapi/misc/xilinx_sdfec.h + :doc: XSDFEC_STOP_DEV + +.. c:macro:: XSDFEC_GET_STATUS +.. kernel-doc:: include/uapi/misc/xilinx_sdfec.h + :doc: XSDFEC_GET_STATUS + +.. c:macro:: XSDFEC_SET_IRQ +.. kernel-doc:: include/uapi/misc/xilinx_sdfec.h + :doc: XSDFEC_SET_IRQ + +.. c:macro:: XSDFEC_SET_TURBO +.. kernel-doc:: include/uapi/misc/xilinx_sdfec.h + :doc: XSDFEC_SET_TURBO + +.. c:macro:: XSDFEC_ADD_LDPC_CODE_PARAMS +.. kernel-doc:: include/uapi/misc/xilinx_sdfec.h + :doc: XSDFEC_ADD_LDPC_CODE_PARAMS + +.. c:macro:: XSDFEC_GET_CONFIG +.. kernel-doc:: include/uapi/misc/xilinx_sdfec.h + :doc: XSDFEC_GET_CONFIG + +.. c:macro:: XSDFEC_SET_ORDER +.. kernel-doc:: include/uapi/misc/xilinx_sdfec.h + :doc: XSDFEC_SET_ORDER + +.. c:macro:: XSDFEC_SET_BYPASS +.. kernel-doc:: include/uapi/misc/xilinx_sdfec.h + :doc: XSDFEC_SET_BYPASS + +.. c:macro:: XSDFEC_IS_ACTIVE +.. kernel-doc:: include/uapi/misc/xilinx_sdfec.h + :doc: XSDFEC_IS_ACTIVE + +.. c:macro:: XSDFEC_CLEAR_STATS +.. kernel-doc:: include/uapi/misc/xilinx_sdfec.h + :doc: XSDFEC_CLEAR_STATS + +.. c:macro:: XSDFEC_GET_STATS +.. kernel-doc:: include/uapi/misc/xilinx_sdfec.h + :doc: XSDFEC_GET_STATS + +.. c:macro:: XSDFEC_SET_DEFAULT_CONFIG +.. kernel-doc:: include/uapi/misc/xilinx_sdfec.h + :doc: XSDFEC_SET_DEFAULT_CONFIG + +Driver Type Definitions +======================= + +.. kernel-doc:: include/uapi/misc/xilinx_sdfec.h + :internal: |