[PATCH v4 00/23] FSI device driver implementation
Christopher Bostic
cbostic at linux.vnet.ibm.com
Wed Mar 29 10:43:17 PDT 2017
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 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.
Chris Bostic (9):
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: Document FSI master sysfs files in ABI
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
drivers/fsi: Add crc4 helpers
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 communication errors
drivers/fsi/gpio: Add tracepoints for GPIO master
drivers/fsi: Use asynchronous slave mode
Documentation/ABI/testing/sysfs-bus-fsi | 6 +
.../devicetree/bindings/fsi/fsi-master-gpio.txt | 24 +
arch/arm/boot/dts/aspeed-bmc-opp-palmetto.dts | 10 +
arch/arm/boot/dts/aspeed-bmc-opp-romulus.dts | 12 +
drivers/fsi/Kconfig | 26 +
drivers/fsi/Makefile | 3 +
drivers/fsi/fsi-core.c | 835 +++++++++++++++++++++
drivers/fsi/fsi-master-gpio.c | 624 +++++++++++++++
drivers/fsi/fsi-master-hub.c | 327 ++++++++
drivers/fsi/fsi-master.h | 64 ++
drivers/fsi/fsi-scom.c | 263 +++++++
include/linux/fsi.h | 35 +-
include/trace/events/fsi.h | 127 ++++
include/trace/events/fsi_master_gpio.h | 68 ++
14 files changed, 2423 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/trace/events/fsi.h
create mode 100644 include/trace/events/fsi_master_gpio.h
--
1.8.2.2
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