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    Subject[PATCH v7 00/23] FSI device driver implementation
    Date
    Implementation of the IBM 'Flexible Support Interface' (FSI) bus device
    driver. FSI is a high fan out serial bus consisting of a clock and a serial
    data line capable of running at speeds up to 166 MHz.

    This set provides the basic framework to add FSI extensions to the
    Linux bus and device models. Master specific implementations are
    defined to utilize the core FSI function.

    In Linux, we have a core FSI "bus type", along with drivers for FSI
    masters and engines.

    The FSI master drivers expose a read/write interface to the bus address
    space. The master drivers are under drivers/fsi/fsi-master-*.c.

    The core handles probing and discovery of slaves and slave
    engines, using those read/write interfaces. It is responsible for
    creating the endpoint Linux devices corresponding to the discovered
    engines on each slave.

    Slave engines are identified by an 'engine' type, and an optional
    version. Engine, a.k.a. client, drivers are matched and bound to these
    engines during discovery.

    This patch set does not include extended FSI function such as:
    * Cascaded master support
    * Application layer hot plug notification
    * Application layer FSI bus status interface

    Common FSI terminology:

    * Master
    Controller of the FSI bus. Only the master is allowed to control the
    clock line and is the initiator of all transactions on a bus.

    * Slave
    The receiver or target of a master initiated transaction. The slave
    cannot initiate communications on a bus and must respond to any
    master requests for data.

    * CFAM
    Stands for Common Field replaceable unit Access Macro. A CFAM is an
    ASIC residing in any device requiring FSI communications. CFAMs
    consist of an array of hardware 'engines' used for various purposes.
    I2C masters, UARTs, General Purpose IO hardware are common types of
    these engines.

    * Configuration Space / Table
    A table contained at the beginning of each CFAM address space.
    This table lists information such as the CFAM's ID, which engine types
    and versions it has available, as well as its addressing range.

    * FSI Engine driver
    A device driver that registers with the FSI core so that it can access
    devices it owns on an FSI bus.

    * Hub
    An FSI master that connects to an upstream 'primary' master allowing
    high fanout of target devices.

    ----
    Changes in v7:
    - Use GENMASK for bitmask definitions
    - Move instances of dev_info to dev_dbg
    - Add missing return code checks
    - Add API details for fsi_device_read/write/peek()
    - GPIO master: Unscan when unregistering master
    - Document ABI sysfs files raw, term, break, rescan
    - GPIO master: move global spinlock into struct fsi_master_gpio
    - GPIO master: remove redundant checks for valid pin descriptors

    Changes in v6:
    - Remove redundant 'depends on' specifiers in Kconfig for SCOM
    GPIO master and Hub masters.

    Changes in v5:
    - Remove explicit kfree of struct fsi_master in fsi_master_gpio.
    - Remove Palmetto and Romulus dts device tree file udates for FSI gpio
    master

    Changes in v4:
    - endianness: the _read() and _write() APIs are now all *bus endian*,
    so will be the same on all platforms (the previous fsi patches
    exposed as (BMC/FSP) CPU endian, which is variable).
    - device tree: Remove the "ibm," prefix for the fsi core and GPIO
    master compatibility strings, as they're not describing
    IBM-specific
    - device model: Create separate struct devices for each FSI
    master, which fits better with the Linux device model, and allows
    addition of sysfs attributes that are implemented by the fsi core
    - sysfs: there are now sysfs facilities for break and term. Raw
    file supports reads and writes of arbitrary sizes.
    - GPIO master: split the xfer() logic out a little, so that the
    response handling & DPOLL retry mechanism is more obvious
    - GPIO master: simplifications for message construction
    - GPIO master: fixes for some CRC calculations
    - GPIO master: issue TERM in response to DPOLL busy-loops
    - Error handling: rather than handle errors on (potentially) an entire
    cascaded read or write, the error handling is now down on a per-slave
    basis, where we try to reestablish communication in a more "gradual"
    manner, rather than sending a break immediately. May need to add a
    hook to percolate error recovery up to a slave's master but no need
    seen for that at present.
    - Hub master: this is now implemented as a fsi engine driver, as the
    fsi_slave_{read,write}() functions are exported (and the port count
    is available in the hMFSI configuration register)
    This means we need fewer special-cases in the fsi core.
    - Tracepoints: Add tracepoints for FSI core read & write, and another
    set for low-level GPIO in/out operations.

    Changes in v3:
    - Patch set contained an invalid 18/18 test patch not
    meant for community review, corrected.

    Changes in v2:
    - Change from atomic global for master number to ida simple
    interface.
    - Add valid pointer checks on register and unregister utils.
    - Move CRC calculation utilities out of driver to lib path.
    - Clean up white space issues.
    - Remove added list management of master devices and use
    instead the device_for_each_child method available in the
    bus.
    - Add new patch to document FSI bus functionality.
    - Add new patch documenting FSI gpio master.
    - Rearrage patch set to have documentation earlier than code
    implementing it.
    - Document all compatible strings used in device tree bindings.
    - Elaborate documentation definition of FSI GPIO master.
    - Describe in more detail what each GPIO FSI master pin is for.
    - Re-order compatible strings in example binding so that most
    specific device comes first.
    - Indicate proper activation order of all FSI GPIO master pins.
    - Fix an unmatched '>' bracket in the example for binding.
    - Bracket each element of the example bindings individually.
    - Add new patch documenting sysfs-bus-fsi attributes.
    - Merge FSI GPIO master init into probe function.
    - Set pin initial values at time of pin request.
    - Assign value of master->master.dev at probe time.
    - Use get_optional interface for all optional GPIO pins.

    Christopher Bostic (9):
    drivers/fsi: Document FSI master sysfs files in ABI
    drivers/fsi: Set up links for slave communication
    drivers/fsi: Set slave SMODE to init communication
    drivers/fsi: Add master unscan
    drivers/fsi: Add documentation for GPIO bindings
    drivers/fsi: Add client driver register utilities
    drivers/fsi: Add GPIO based FSI master
    drivers/fsi: Add SCOM FSI client device driver
    drivers/fsi: Add hub master support

    Jeremy Kerr (14):
    drivers/fsi: Add fsi master definition
    drivers/fsi: Add slave definition
    drivers/fsi: Add empty master scan
    lib: Add crc4 module
    drivers/fsi: Add slave & master read/write APIs
    drivers/fsi: Implement slave initialisation
    drivers/fsi: scan slaves & register devices
    drivers/fsi: Add device read/write/peek API
    drivers/fsi: Add sysfs files for FSI master & slave accesses
    drivers/fsi: expose direct-access slave API
    drivers/fsi: Add tracepoints for low-level operations
    drivers/fsi: Add error handling for slave
    drivers/fsi/gpio: Add tracepoints for GPIO master
    drivers/fsi: Use asynchronous slave mode

    Documentation/ABI/testing/sysfs-bus-fsi | 38 +
    .../devicetree/bindings/fsi/fsi-master-gpio.txt | 24 +
    drivers/fsi/Kconfig | 26 +
    drivers/fsi/Makefile | 3 +
    drivers/fsi/fsi-core.c | 836 +++++++++++++++++++++
    drivers/fsi/fsi-master-gpio.c | 604 +++++++++++++++
    drivers/fsi/fsi-master-hub.c | 327 ++++++++
    drivers/fsi/fsi-master.h | 43 ++
    drivers/fsi/fsi-scom.c | 263 +++++++
    include/linux/crc4.h | 8 +
    include/linux/fsi.h | 35 +-
    include/trace/events/fsi.h | 127 ++++
    include/trace/events/fsi_master_gpio.h | 68 ++
    lib/Kconfig | 8 +
    lib/Makefile | 1 +
    lib/crc4.c | 46 ++
    16 files changed, 2456 insertions(+), 1 deletion(-)
    create mode 100644 Documentation/ABI/testing/sysfs-bus-fsi
    create mode 100644 Documentation/devicetree/bindings/fsi/fsi-master-gpio.txt
    create mode 100644 drivers/fsi/fsi-master-gpio.c
    create mode 100644 drivers/fsi/fsi-master-hub.c
    create mode 100644 drivers/fsi/fsi-master.h
    create mode 100644 drivers/fsi/fsi-scom.c
    create mode 100644 include/linux/crc4.h
    create mode 100644 include/trace/events/fsi.h
    create mode 100644 include/trace/events/fsi_master_gpio.h
    create mode 100644 lib/crc4.c

    --
    1.8.2.2

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