Commit Graph

18 Commits

Author SHA1 Message Date
Joel Stanley ab1b79159a fsi: scom: Remove retries in indirect scoms
In commit f72ddbe1d7 ("fsi: scom: Remove retries") the retries were
removed from get and put scoms. That patch missed the retires in get and
put indirect scom.

For the same reason, remove them from the scom driver to allow the
caller to decide to retry.

This removes the following special case which would have caused the
retry code to return early:

 -       if ((ind_data & XSCOM_DATA_IND_COMPLETE) || (err != SCOM_PIB_BLOCKED))
 -               return 0;

I believe this case is handled.

Fixes: f72ddbe1d7 ("fsi: scom: Remove retries")
Signed-off-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20211207033811.518981-3-joel@jms.id.au
Signed-off-by: Joel Stanley <joel@jms.id.au>
2022-01-31 15:56:55 +10:30
Joel Stanley d46fddd52d fsi: scom: Fix error handling
SCOM error handling is made complex by trying to pass around two bits of
information: the function return code, and a status parameter that
represents the CFAM error status register.

The commit f72ddbe1d7 ("fsi: scom: Remove retries") removed the
"hidden" retries in the SCOM driver, in preference of allowing the
calling code (userspace or driver) to decide how to handle a failed
SCOM. However it introduced a bug by attempting to be smart about the
return codes that were "errors" and which were ok to fall through to the
status register parsing.

We get the following errors:

 - EINVAL or ENXIO, for indirect scoms where the value is invalid
 - EINVAL, where the size or address is incorrect
 - EIO or ETIMEOUT, where FSI write failed (aspeed master)
 - EAGAIN, where the master detected a crc error (GPIO master only)
 - EBUSY, where the bus is disabled (GPIO master in external mode)

In all of these cases we should fail the SCOM read/write and return the
error.

Thanks to Dan Carpenter for the detailed bug report.

Fixes: f72ddbe1d7 ("fsi: scom: Remove retries")
Link: https://lists.ozlabs.org/pipermail/linux-fsi/2021-November/000235.html
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20211207033811.518981-2-joel@jms.id.au
Signed-off-by: Joel Stanley <joel@jms.id.au>
2022-01-31 15:56:55 +10:30
Joel Stanley f72ddbe1d7 fsi: scom: Remove retries
On a functioning FSI link there is not need to retry a write when doing
a scom in the driver.

Allow the higher layers (eg. userspace) to attempt a retry if they want,
or to accept that the address they are talking to is not accessible.

By removing the retries we can separate the error handling from retry
logic. In particular -EBUSY was used to force the get/put scom logic to
retry.

Signed-off-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/20210527070109.225198-1-joel@jms.id.au
Signed-off-by: Joel Stanley <joel@jms.id.au>
2021-06-04 14:24:02 +09:30
Eddie James a5c317dac5 fsi: scom: Reset the FSI2PIB engine for any error
The error bits in the FSI2PIB status are only cleared by a reset. So
the driver needs to perform a reset after seeing any of the FSI2PIB
errors, otherwise subsequent operations will also look like failures.

Fixes: 6b293258cd ("fsi: scom: Major overhaul")
Signed-off-by: Eddie James <eajames@linux.ibm.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/20210329151344.14246-1-eajames@linux.ibm.com
Signed-off-by: Joel Stanley <joel@jms.id.au>
2021-06-04 14:19:48 +09:30
Rikard Falkeborn 59165631b7 fsi: scom: Constify scom_ids
The only usage of scom_ids is to assign its address to the id_table
field in the fsi_driver struct, which is a const pointer, so make it
const to allow the compiler to put it in read-only memory

Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
2020-09-10 12:22:51 +09:30
Eddie James 8919dfcb31 fsi: scom: Don't abort operations for minor errors
The scom driver currently fails out of operations if certain system
errors are flagged in the status register; system checkstop, special
attention, or recoverable error. These errors won't impact the ability
of the scom engine to perform operations, so the driver should continue
under these conditions.
Also, don't do a PIB reset for these conditions, since it won't help.

Fixes: 6b293258cd ("fsi: scom: Major overhaul")
Signed-off-by: Eddie James <eajames@linux.ibm.com>
Cc: stable <stable@vger.kernel.org>
Acked-by: Jeremy Kerr <jk@ozlabs.org>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/20190827041249.13381-1-jk@ozlabs.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-28 22:59:18 +02:00
Thomas Gleixner 6b99076ced treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 469
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 mergchantability 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 2 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Enrico Weigelt <info@metux.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081202.997941624@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-19 17:09:11 +02:00
Brajeswar Ghosh d20810530b fsi: fsi-scom.c: Remove duplicate header
Remove linux/cdev.h which is included more than once

Signed-off-by: Brajeswar Ghosh <brajeswar.linux@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2018-11-26 10:13:04 +11:00
Benjamin Herrenschmidt aa1221b258 fsi: scom: Fix NULL dereference
The chardev conversion forgot to copy the fsi_dev,
silly mistake, compounded by a testing mistake on
my side, this specific driver wasn't being tested
properly.

Fixes: d8f4587655 "fsi: scom: Convert to use the new chardev"
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2018-08-06 12:27:04 +10:00
Benjamin Herrenschmidt d8f4587655 fsi: scom: Convert to use the new chardev
This converts FSI scom to use the new fsi-core controlled
chardev allocator and use a real cdev instead of a miscdev.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2018-07-27 09:57:55 +10:00
Benjamin Herrenschmidt 6b293258cd fsi: scom: Major overhaul
This was too hard to split ... this adds a number of features
to the SCOM user interface:

 - Support for indirect SCOMs

 - read()/write() interface now handle errors and retries

 - New ioctl() "raw" interface for use by debuggers

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Eddie James <eajames@linux.vnet.ibm.com>
Reviewed-by: Alistair Popple <alistair@popple.id.au>
2018-06-18 15:11:53 +10:00
Benjamin Herrenschmidt f143304442 fsi: scom: Add register definitions
Add a few more register and bit definitions, also define and use
SCOM_READ_CMD (which is 0 but it makes the code clearer)

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Eddie James <eajames@linux.vnet.ibm.com>
2018-06-18 14:33:56 +10:00
Benjamin Herrenschmidt 5a3c2f7656 fsi: scom: Fixup endian annotations
Use the proper annotated type __be32 and fixup the
accessor used for get_scom()

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Eddie James <eajames@linux.vnet.ibm.com>
2018-06-18 14:33:56 +10:00
Benjamin Herrenschmidt bd21336457 fsi: scom: Whitespace fixes
No functional changes

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Eddie James <eajames@linux.vnet.ibm.com>
2018-06-18 14:33:56 +10:00
Benjamin Herrenschmidt 162c394673 fsi: scom: Add mutex around FSI2PIB accesses
Otherwise, multiple clients can open the driver and attempt
to access the PIB at the same time, thus clobbering each other
in the process.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Eddie James <eajames@linux.vnet.ibm.com>
2018-06-18 14:33:56 +10:00
Eddie James 52b7116e88 fsi: scom: Remove PIB reset during probe
The PIB reset causes problems for the running P9 chip. The reset
shouldn't be performed by this driver.

Signed-off-by: Eddie James <eajames@linux.vnet.ibm.com>
Reviewed-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Tested-by: Joel Stanley <joel@jms.id.au>
2018-06-12 14:05:34 +10:00
Edward A. James 47a6623b2d drivers/fsi/scom: Remove reset before every putscom
Reset causes problems for operations requiring multiple scoms (e.g. i2c
over scom). Instead, reset scom engine during probe.

Signed-off-by: Edward A. James <eajames@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-08-28 17:15:16 +02:00
Christopher Bostic 680ca6dcf5 drivers/fsi: Add SCOM FSI client device driver
Create a simple SCOM engine device driver that reads and writes
its control registers via an FSI bus.

Includes changes from Edward A. James <eajames@us.ibm.com>.

Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Edward A. James <eajames@us.ibm.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-09 11:52:09 +02:00