fsi: Lock mutex for master device registration

Because master device registration may cause hub master scans, or
user scans may begin before device registration has ended, so the
master scan lock must be held while registering the device.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20230809180814.151984-3-eajames@linux.ibm.com
Signed-off-by: Joel Stanley <joel@jms.id.au>

fsi: Improve master indexing

Master indexing is problematic if a hub is rescanned while the
root master is being rescanned. Always allocate an index for the
FSI master, and set the device name if it hasn't already been set.
Move the call to ida_free to the bottom of master unregistration
and set the number of links to 0 in case another call to scan
comes in before the device is removed.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20230809180814.151984-2-eajames@linux.ibm.com
Signed-off-by: Joel Stanley <joel@jms.id.au>

fsi: core: Switch to ida_alloc/free

ida_simple_get/remove are deprecated, so switch to ida_alloc/free.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20230612195657.245125-11-eajames@linux.ibm.com
Signed-off-by: Joel Stanley <joel@jms.id.au>

fsi: core: Fix legacy minor numbering

The legacy minor numbering shifts the chip id too much,
resulting in ids that overlap with regular ids. Since there
are only 2 bits for 4 types, only shift the chip id by 2
to fit the legacy ids in their reserved space.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20230612195657.245125-10-eajames@linux.ibm.com
Signed-off-by: Joel Stanley <joel@jms.id.au>

fsi: core: Add trace events for scan and unregister

Add more trace events for the scanning and unregistration
functions for debug purposes.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/20230612195657.245125-9-eajames@linux.ibm.com
Signed-off-by: Joel Stanley <joel@jms.id.au>

fsi: Use of_match_table for bus matching if specified

Since we have two scom drivers, use the standard of matching if
the driver specifies a table so that the right devices go to the
right driver.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20230612195657.245125-4-eajames@linux.ibm.com
Signed-off-by: Joel Stanley <joel@jms.id.au>

fsi: Add aliased device numbering

The I2C and SPI subsystems can use an aliased name to number the device.
Add similar support to the FSI subsystem for any device type.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20230612195657.245125-3-eajames@linux.ibm.com
Signed-off-by: Joel Stanley <joel@jms.id.au>

fsi: Move fsi_slave structure definition to header

Some FSI drivers may have need of the slave definition, so
move it to a header file. Also use one macro for obtaining a
pointer to the fsi_master structure.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20230612195657.245125-2-eajames@linux.ibm.com
Signed-off-by: Joel Stanley <joel@jms.id.au>

fsi: Use of_property_read_reg() to parse "reg"

Use the recently added of_property_read_reg() helper to get the
untranslated "reg" address value.

Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20230609183056.1765183-1-robh@kernel.org
Signed-off-by: Joel Stanley <joel@jms.id.au>

driver core: make struct device_type.devnode() take a const *

The devnode() callback in struct device_type should not be modifying the
device that is passed into it, so mark it as a const * and propagate the
function signature changes out into all relevant subsystems that use
this callback.

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Alison Schofield <alison.schofield@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Ben Widawsky <bwidawsk@kernel.org>
Cc: Jeremy Kerr <jk@ozlabs.org>
Cc: Joel Stanley <joel@jms.id.au>
Cc: Alistar Popple <alistair@popple.id.au>
Cc: Eddie James <eajames@linux.ibm.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jilin Yuan <yuanjilin@cdjrlc.com>
Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Cc: Won Chung <wonchung@google.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20230111113018.459199-7-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fsi: core: Check error number after calling ida_simple_get

If allocation fails, the ida_simple_get() will return error number.
So master->idx could be error number and be used in dev_set_name().
Therefore, it should be better to check it and return error if fails,
like the ida_simple_get() in __fsi_get_new_minor().

Fixes: 09aecfab93b8 ("drivers/fsi: Add fsi master definition")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Reviewed-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20220111073411.614138-1-jiasheng@iscas.ac.cn
Signed-off-by: Joel Stanley <joel@jms.id.au>

fsi: cleanup extern usage in function definition

Smatch reports these issues
fsi-core.c:395:12: warning: function 'fsi_slave_claim_range'
with external linkage has definition
fsi-core.c:409:13: warning: function 'fsi_slave_release_range'
with external linkage has definition

The storage-class-specifier extern is not needed in a
definition, so remove it.

Signed-off-by: Tom Rix <trix@redhat.com>
Link: https://lore.kernel.org/r/20220403140937.3833578-1-trix@redhat.com
Signed-off-by: Joel Stanley <joel@jms.id.au>

fsi: Add trace events in initialization path

Add definitions for trace events to show the scanning flow.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20220207161640.35605-1-eajames@linux.ibm.com
Signed-off-by: Joel Stanley <joel@jms.id.au>

fsi: core: Fix return of error values on failures

Currently the cfam_read and cfam_write functions return the provided
number of bytes given in the count parameter and not the error return
code in variable rc, hence all failures of read/writes are being
silently ignored. Fix this by returning the error code in rc.

Addresses-Coverity: ("Unused value")
Fixes: d1dcd6782576 ("fsi: Add cfam char devices")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Jeremy Kerr <jk@ozlabs.org>
Link: https://lore.kernel.org/r/20210603122812.83587-1-colin.king@canonical.com
Signed-off-by: Joel Stanley <joel@jms.id.au>

fsi: core: Set slave local bus ownership during init

The driver ought to claim local bus ownership of the slave it's
communicating with.

This is for multi-master setups. The slave (in theory) will deny access
to masters who try to access the CFAM address space but who don't "own"
the bus.

As driver doesn't seem to perform any other teardown there is no need to
"un-claim" ownership at teardown. Also I'm not aware of any multi-master
setup using this driver so it shouldn't actually matter. Also, the
hardware doesn't seem to enforce this despite being required in the
specification...

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>

fsi: core: Disable link when slave init fails

In the case that links don't have slaves or fail to be accessed, the
master should disable the link during the scan since it won't be using
the slave.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>

fsi: master: Add boolean parameter to link_enable function

Add the ability to disable a link with a boolean parameter to the
link_enable function. This is necessary so that the master can disable
links that it isn't using; for example, links to slaves that fail
initialization.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>

fsi: fsi_master_class can be static

There are no users outside of this file.

Fixes: 0604d53d4da8 ("fsi: Add fsi-master class")
Signed-off-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/20191108051945.7109-7-joel@jms.id.au
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fsi: core: Fix small accesses and unaligned offsets via sysfs

Subtracting the offset delta from four-byte alignment lead to wrapping
of the requested length where `count` is less than `off`. Generalise the
length handling to enable and optimise aligned access sizes for all
offset and size combinations. The new formula produces the following
results for given offset and count values:

offset count | length
--------------+-------
0 1 | 1
0 2 | 2
0 3 | 2
0 4 | 4
0 5 | 4
1 1 | 1
1 2 | 1
1 3 | 1
1 4 | 1
1 5 | 1
2 1 | 1
2 2 | 2
2 3 | 2
2 4 | 2
2 5 | 2
3 1 | 1
3 2 | 1
3 3 | 1
3 4 | 1
3 5 | 1

We might need something like this for the cfam chardevs as well, for
example we don't currently implement any alignment restrictions /
handling in the hardware master driver.

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/20191108051945.7109-6-joel@jms.id.au
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fsi: Move master attributes to fsi-master class

Populate fsi_master_class->dev_attrs with the existing attribute
definitions, so we don't need to explicitly register.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Acked-by: Alistair Popple <alistair@popple.id.au>
Link: https://lore.kernel.org/r/20191108051945.7109-3-joel@jms.id.au
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fsi: Add fsi-master class

This change adds a device class for FSI masters, allowing access under
/sys/class/fsi-master/, and easier udev rules.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Acked-by: Alistair Popple <alistair@popple.id.au>
Link: https://lore.kernel.org/r/20191108051945.7109-2-joel@jms.id.au
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fsi/core: Fix error paths on CFAM init

Change d1dcd67825 re-worked the struct fsi_slave initialisation in
fsi_slave_init, but introduced a few inconsitencies: the slave->dev is
now registered through cdev_device_add, but we may kfree() the device
out from underneath the cdev registration. We may also leave an IDA
allocated.

This change fixes the error paths, so that we kfree() only before the
device is registered with the core code. We also move the smode write to
before we start creating proper devices, as it's the most likely to
fail. We also remove the IDA-allocated minor on error, and properly
clean up the of_node.

Fixes: d1dcd6782576 ("fsi: Add cfam char devices")
Reported-by: Lei YU <mine260309@gmail.com>
Tested-by: John Wang <wangzqbj@inspur.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation 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

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 655 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070034.575739538@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fsi: Prevent multiple concurrent rescans

The bus scanning process isn't terribly good at parallel attempts
at rescanning the same bus. Let's have a per-master mutex protecting
the scanning process.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

fsi: Add cfam char devices

This aims to deprecate the "raw" sysfs file used for directly
accessing the CFAM and instead use a char device like the
other sub drivers.

Since it reworks the slave creation code and adds a cfam device
type, we also use the opportunity to convert the attributes
to attribute groups and add a couple more.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

fsi: Add new central chardev support

The various FSI devices (sbefifo, occ, scom, more to come)
currently use misc devices.

This is problematic as the minor device space for misc is
limited and there can be a lot of them. Also it limits our
ability to move them to a dedicated /dev/fsi directory or
to be smart about device naming and numbering.

It also means we have IDAs on every single of these drivers

This creates a common fsi "device_type" for the optional
/dev/fsi grouping and a dev_t allocator for all FSI devices.

"Legacy" devices get to use a backward compatible numbering
scheme (as long as chip id <16 and there's only one copy
of a given unit type per chip).

A single major number and a single IDA are shared for all
FSI devices.

This doesn't convert the FSI device drivers to use the new
scheme yet, they will be converted individually.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

fsi: Add support for device-tree provided chip IDs

They get retrieved from the device-tree and exposed
as an attribute in sysfs

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

fsi: Don't use device_unregister() in fsi_master_register()

In the error path of fsi_master_register(), we currently
use device_unregister(). This will cause the last reference
to the structure to be dropped, thus freeing the enclosing
structure, which isn't what the callers want.

Use device_del() instead so that we return to the caller
with a refcount of 1. The caller can then assume that it
must use put_device() after a call to fsi_master_register()
regardless of whether the latter suceeded or failed.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

fsi: Add mechanism to set the tSendDelay and tEchoDelay values

Those values control the amount of "dummy" clocks between commands and
between a command and its response.

This adds a way to configure them from sysfs (to be later extended to
defaults in the device-tree). The default remains 16 (the HW default).

This is only supported if the backend supports the new link_config()
callback to configure the generation of those delays.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
---

fsi: Move code around to avoid forward declaration

Move fsi_slave_set_smode() and its helpers to before it's
first user and remove the corresponding forward declaration.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>

fsi: core: Fix sparse warnings

fsi-core.c:210:9: warning: cast to restricted __be32
fsi-core.c:210:9: warning: cast to restricted __be32
fsi-core.c:210:9: warning: cast to restricted __be32
fsi-core.c:210:9: warning: cast to restricted __be32
fsi-core.c:210:9: warning: cast to restricted __be32
fsi-core.c:210:9: warning: cast to restricted __be32
fsi-core.c:210:9: warning: cast to restricted __be32
fsi-core.c:210:9: warning: cast to restricted __be32
fsi-core.c:210:9: warning: cast to restricted __be32
fsi-core.c:210:9: warning: cast to restricted __be32
fsi-core.c:210:9: warning: cast to restricted __be32
fsi-core.c:210:9: warning: cast to restricted __be32
fsi-core.c:606:15: warning: incorrect type in assignment (different base types)
fsi-core.c:606:15: expected unsigned int [unsigned] [assigned] [usertype] smode
fsi-core.c:606:15: got restricted __be32 [usertype] <noident>
fsi-core.c:492:28: warning: expression using sizeof(void)
fsi-core.c:520:29: warning: expression using sizeof(void)
fsi-core.c:682:19: warning: cast to restricted __be32
fsi-core.c:682:19: warning: cast to restricted __be32
fsi-core.c:682:19: warning: cast to restricted __be32
fsi-core.c:682:19: warning: cast to restricted __be32
fsi-core.c:682:19: warning: cast to restricted __be32
fsi-core.c:682:19: warning: cast to restricted __be32
fsi-core.c:706:24: warning: incorrect type in assignment (different base types)
fsi-core.c:706:24: expected unsigned int [unsigned] [usertype] llmode
fsi-core.c:706:24: got restricted __be32 [usertype] <noident>

Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

fsi: core: Add check for master property no-scan-on-init

Prior to scanning a master check if the optional property
no-scan-on-init is present. If it is then avoid scanning. This is
necessary in cases where a master scan could interfere with another
FSI master on the same bus.

Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Acked-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fsi: core: Reduce console output during normal scan

To reduce amount of console output during boot / power up make
all normal path scan related messages debug type.

Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Acked-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fsi: Match fsi slaves and engines to available dt nodes

This change populates device tree nodes for scanned FSI slaves and
engines. If the master populates ->of_node of the FSI master device,
we'll look for matching slaves, and under those slaves we'll look for
matching engines.

This means that FSI drivers will have their ->of_node pointer populated
if there's a corresponding DT node, which they can use for further
device discover.

Presence of device tree nodes is optional, and only required for
fsi device drivers that need extra properties, or subordinate devices,
to be enumerated.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fsi: Fix one and two byte bus reads/writes

Address checker fixed to allow one and two byte reads/writes.
Address alignments for each size verified.

Signed-off-by: Edward James <eajames@us.ibm.com>
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Acked-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fsi: Add fsi_master_rescan()

We'll want non-core fsi code to trigger a rescan, so introduce a
non-static fsi_master_rescan() function. Use this for the existing
unscan/scan behaviour too.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Christopher Bostic <clbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/fsi: make a couple of functions static

The functions fsi_slave_report_and_clear_errors and fsi_slave_handle_error
are local to the source and do not need to be in global scope, so make
them static.

Cleans up sparse warnings:
symbol 'fsi_slave_report_and_clear_errors' was not declared. Should it
be static?
symbol 'fsi_slave_handle_error' was not declared. Should it be static?

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/fsi: add const to bin_attribute structures

Declare bin_attribute structures as const as they are only passed as an
argument to the function device_create_bin_file. This argument is of
type const, so declare the structure as const.

Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/fsi: fix fsi_slave_mode prototype

gcc warns about the return type of this function:

drivers/fsi/fsi-core.c:535:8: error: type qualifiers ignored on function return type [-Werror=ignored-qualifiers]

This removes the 'const' attribute, as suggested by the warning.

Fixes: 2b37c3e285f9 ("drivers/fsi: Set slave SMODE to init communication")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fsi: core: register with postcore_initcall

When testing an i2c driver that is a fsi bus driver, I saw the following
oops:

kernel BUG at drivers/base/driver.c:153!
Internal error: Oops - BUG: 0 [#1] ARM

[<8027cb1c>] (driver_register) from [<80344e88>] (fsi_driver_register+0x2c/0x38)
[<80344e88>] (fsi_driver_register) from [<805f5ebc>] (fsi_i2c_driver_init+0x1c/0x24)
[<805f5ebc>] (fsi_i2c_driver_init) from [<805d1f14>] (do_one_initcall+0xb4/0x170)
[<805d1f14>] (do_one_initcall) from [<805d20f0>] (kernel_init_freeable+0x120/0x1dc)
[<805d20f0>] (kernel_init_freeable) from [<8043f4a8>] (kernel_init+0x18/0x104)
[<8043f4a8>] (kernel_init) from [<8000a5e8>] (ret_from_fork+0x14/0x2c)

This is because the fsi bus had not been registered. This fix registers the bus
with postcore_initcall instead, to ensure it is registered earlier on.

When the fsi core is used as a module this should not be a problem as the fsi
driver will depend on the fsi bus type symbol, and will therefore load the core
before the driver.

Fixes: 0508ad1fff11 ("drivers/fsi: Add empty fsi bus definitions")
Signed-off-by: Joel Stanley <joel@jms.id.au>
Acked-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/fsi: Add module license to core driver

Add missing MODULE_LICENSE("GPL") to the core FSI driver.

Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/fsi: Use asynchronous slave mode

For slaves that are behind a software-clocked master, we want FSI CFAMs
to run asynchronously to the FSI clock, so set up our slaves to be in
async mode.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/fsi: Add error handling for slave

This change implements error handling in the FSI core, by cleaining up
and retrying failed operations, using the SISC, TERM and BREAK
facilities.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/fsi: Add tracepoints for low-level operations

Trace low level read and write FSI bus operations.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/fsi: expose direct-access slave API

Allow drivers to access the slave address ranges.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/fsi: Add sysfs files for FSI master & slave accesses

This change adds a 'raw' file for reads & writes, and a 'term' file for
the TERM command, and a 'break' file for issuing a BREAK.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/fsi: Add client driver register utilities

Add driver_register and driver_unregister wrappers for FSI.

Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/fsi: Add master unscan

Allow a master to undo a previous scan. Should a master scan a bus
twice it will need to ensure it doesn't double register any
previously detected device.

Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
----
v7 - Unscan when unregistering master
- Remove leading '__'s from function names
- Return fail state for sysfs rescan file
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/fsi: Add device read/write/peek API

This change introduces the fsi device API: simple read, write and peek
accessors for the devices' address spaces.

Includes contributions from Christopher Bostic
<cbostic@linux.vnet.ibm.com> and Edward A. James <eajames@us.ibm.com>.

Signed-off-by: Edward A. James <eajames@us.ibm.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/fsi: scan slaves & register devices

Now that we have fsi_slave devices, scan each for endpoints, and
register them on the fsi bus.

Includes contributions from Christopher Bostic
<cbostic@linux.vnet.ibm.com>.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/fsi: Set slave SMODE to init communication

Set CFAM to appropriate ID so that the controlling master can manage
link memory ranges. Add slave engine register definitions.

Includes changes from Jeremy Kerr <jk@ozlabs.org>.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/fsi: Implement slave initialisation

Implement fsi_slave_init: if we can read a chip ID, create fsi_slave
devices and register with the driver core.

Includes changes from Christopher Bostic <cbostic@linux.vnet.ibm.com>.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/fsi: Set up links for slave communication

Enable each link and send a break command, and try to detect a slave by
reading from the SMODE register.

Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/fsi: Add slave & master read/write APIs

Introduce functions to perform reads/writes on the slave address space;
these simply pass the request on the slave's master with the correct
link and slave ID.

We implement these on top of similar helpers for the master.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Chris Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/fsi: Add empty master scan

When a new fsi master is added, we will need to scan its links, and
slaves attached to those links. This change introduces a little shell to
iterate the links, which we will populate with the actual slave scan in
a later change.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Chris Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/fsi: Add slave definition

Add the initial fsi slave device, which is private to the core code.
This will be a child of the master, and parent to endpoint devices.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Chris Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/fsi: Add fsi master definition

Add a `struct fsi_master` to represent a FSI master controller.

FSI master drivers register one of these structs to provide
device-specific of the standard operations: read/write/term/break and
link control.

Includes changes from Edward A. James <eajames@us.ibm.com> & Jeremy Kerr
<jk@ozlabs.org>.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Chris Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/fsi: add driver to device matches

Driver bind to devices based on the engine types & (optional) versions.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Chris Bostic <cbostic@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/fsi: Add empty fsi bus definitions

This change adds the initial (empty) fsi bus definition, and introduces
drivers/fsi/.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Chris Bostic <cbostic@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>