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2022-01-31fsi: scom: Remove retries in indirect scomsJoel Stanley1-26/+15
In commit f72ddbe1d7b7 ("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: f72ddbe1d7b7 ("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>
2022-01-31fsi: scom: Fix error handlingJoel Stanley1-2/+2
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 f72ddbe1d7b7 ("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: f72ddbe1d7b7 ("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>
2021-06-04fsi: scom: Remove retriesJoel Stanley1-60/+29
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>
2021-06-04fsi: scom: Reset the FSI2PIB engine for any errorEddie James1-7/+9
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: 6b293258cded ("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>
2020-09-10fsi: scom: Constify scom_idsRikard Falkeborn1-1/+1
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>
2019-08-28fsi: scom: Don't abort operations for minor errorsEddie James1-7/+1
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: 6b293258cded ("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>
2019-06-19treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 469Thomas Gleixner1-9/+1
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>
2018-11-26fsi: fsi-scom.c: Remove duplicate headerBrajeswar Ghosh1-1/+0
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>
2018-08-06fsi: scom: Fix NULL dereferenceBenjamin Herrenschmidt1-0/+1
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: d8f4587655f9 "fsi: scom: Convert to use the new chardev" Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2018-07-27fsi: scom: Convert to use the new chardevBenjamin Herrenschmidt1-50/+80
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>
2018-06-18fsi: scom: Major overhaulBenjamin Herrenschmidt1-30/+394
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>
2018-06-18fsi: scom: Add register definitionsBenjamin Herrenschmidt1-1/+18
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>
2018-06-18fsi: scom: Fixup endian annotationsBenjamin Herrenschmidt1-5/+4
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>
2018-06-18fsi: scom: Whitespace fixesBenjamin Herrenschmidt1-4/+4
No functional changes Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Reviewed-by: Eddie James <eajames@linux.vnet.ibm.com>
2018-06-18fsi: scom: Add mutex around FSI2PIB accessesBenjamin Herrenschmidt1-7/+18
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>
2018-06-12fsi: scom: Remove PIB reset during probeEddie James1-8/+0
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>
2017-08-28drivers/fsi/scom: Remove reset before every putscomEdward A. James1-6/+4
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>
2017-06-09drivers/fsi: Add SCOM FSI client device driverChristopher Bostic1-0/+263
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>
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