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path: root/drivers/spi/spi-fsi.c
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2021-10-27spi: fsi: Fix contention in the FSI2SPI engineEddie James
There was nothing to protect multiple SPI controllers on the same FSI2SPI device from being accessed through the FSI2SPI device at the same time. For example, multiple writes to the command and data registers might occur for different SPI controllers, resulting in complete chaos in the SPI engine. To prevent this, add a FSI2SPI device level mutex and lock it in the SPI register read and write functions. Fixes: bbb6b2f9865b ("spi: Add FSI-attached SPI controller driver") Signed-off-by: Eddie James <eajames@linux.ibm.com> Link: https://lore.kernel.org/r/20211026193327.52420-1-eajames@linux.ibm.com Signed-off-by: Mark Brown <broonie@kernel.org>
2021-10-05spi: fsi: Print status on errorEddie James
Print the SPI engine status register when an error is detected. This will aid tremendously in debugging failed transactions. Signed-off-by: Eddie James <eajames@linux.ibm.com> Link: https://lore.kernel.org/r/20211004195149.29759-1-eajames@linux.ibm.com Signed-off-by: Mark Brown <broonie@kernel.org>
2021-07-19spi: fsi: Reduce max transfer size to 8 bytesEddie James
Security changes have forced the SPI controllers to be limited to 8 byte reads. Refactor the sequencing to just handle 8 bytes at a time. Signed-off-by: Eddie James <eajames@linux.ibm.com> Link: https://lore.kernel.org/r/20210716133915.14697-2-eajames@linux.ibm.com Signed-off-by: Mark Brown <broonie@kernel.org> Cc: stable@vger.kernel.org
2021-04-21spi: fsi: add a missing of_node_putChristophe JAILLET
'for_each_available_child_of_node' performs an of_node_get on each iteration, so a return from the middle of the loop requires an of_node_put. Fixes: bbb6b2f9865b ("spi: Add FSI-attached SPI controller driver") Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Link: https://lore.kernel.org/r/504e431b900341249d331b868d90312cf41f415a.1618947919.git.christophe.jaillet@wanadoo.fr Signed-off-by: Mark Brown <broonie@kernel.org>
2021-03-25spi: fsi: Remove multiple sequenced ops for restricted chipsEddie James
Updated restricted chips have trouble processing multiple sequenced operations. So remove the capability to sequence multiple operations and reduce the maximum transfer size to 8 bytes. Signed-off-by: Eddie James <eajames@linux.ibm.com> Reviewed-by: Joel Stanley <joel@jms.id.au> Link: https://lore.kernel.org/r/20210324220516.41192-1-eajames@linux.ibm.com Signed-off-by: Mark Brown <broonie@kernel.org>
2020-11-11spi: fsi: Fix transfer returning without finalizing messageEddie James
In the case that the SPI mux isn't set, the transfer_one_message function returns without finalizing the message. This means that the transfer never completes, resulting in hung tasks and an eventual kernel panic. Fix it by finalizing the transfer in this case. Fixes: 9211a441e606 ("spi: fsi: Check mux status before transfers") Signed-off-by: Eddie James <eajames@linux.ibm.com> Reviewed-by: Joel Stanley <joel@jms.id.au> Link: https://lore.kernel.org/r/20201110214736.25718-1-eajames@linux.ibm.com Signed-off-by: Mark Brown <broonie@kernel.org>
2020-09-17spi: fsi: Check mux status before transfersEddie James
The SPI controllers are not accessible if the mux isn't set. Therefore, check the mux status before starting a transfer and fail out if it isn't set. Signed-off-by: Eddie James <eajames@linux.ibm.com> Signed-off-by: Joel Stanley <joel@jms.id.au> Link: https://lore.kernel.org/r/20200909222857.28653-7-eajames@linux.ibm.com Signed-off-by: Mark Brown <broonie@kernel.org>
2020-09-17spi: fsi: Implement restricted size for certain controllersEddie James
Some of the FSI-attached SPI controllers cannot use the loop command in programming the sequencer due to security requirements. Check the devicetree compatibility that indicates this condition and restrict the size for these controllers. Also, add more transfers directly in the sequence up to the length of the sequence register. Fixes: bbb6b2f9865b ("spi: Add FSI-attached SPI controller driver") Signed-off-by: Eddie James <eajames@linux.ibm.com> Reviewed-by: Joel Stanley <joel@jms.id.au> Signed-off-by: Joel Stanley <joel@jms.id.au> Link: https://lore.kernel.org/r/20200909222857.28653-6-eajames@linux.ibm.com Signed-off-by: Mark Brown <broonie@kernel.org>
2020-09-17spi: fsi: Fix use of the bneq+ sequencer instructionBrad Bishop
All of the switches in N2_count_control in the counter configuration are required to make the branch if not equal and increment command work. Set them when using bneq+. A side effect of this mode requires a dummy write to TDR when both transmitting and receiving otherwise the controller won't start shifting receive data. It is likely not possible to avoid TDR underrun errors in this mode and they are harmless, so do not check for them. Fixes: bbb6b2f9865b ("spi: Add FSI-attached SPI controller driver") Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com> Signed-off-by: Eddie James <eajames@linux.ibm.com> Reviewed-by: Joel Stanley <joel@jms.id.au> Signed-off-by: Joel Stanley <joel@jms.id.au> Link: https://lore.kernel.org/r/20200909222857.28653-4-eajames@linux.ibm.com Signed-off-by: Mark Brown <broonie@kernel.org>
2020-09-17spi: fsi: Fix clock running too fastBrad Bishop
Use a clock divider tuned to a 200MHz FSI bus frequency (the maximum). Use of the previous divider at 200MHz results in corrupt data from endpoint devices. Ideally the clock divider would be calculated from the FSI clock, but that would require some significant work on the FSI driver. With FSI frequencies slower than 200MHz, the SPI clock will simply run slower, but safely. Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com> Signed-off-by: Eddie James <eajames@linux.ibm.com> Signed-off-by: Joel Stanley <joel@jms.id.au> Link: https://lore.kernel.org/r/20200909222857.28653-3-eajames@linux.ibm.com Signed-off-by: Mark Brown <broonie@kernel.org>
2020-09-17spi: fsi: Handle 9 to 15 byte transfers lengthsBrad Bishop
The trailing <len> - 8 bytes of transfer data in this size range is no longer ignored. Fixes: bbb6b2f9865b ("spi: Add FSI-attached SPI controller driver") Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com> Signed-off-by: Eddie James <eajames@linux.ibm.com> Reviewed-by: Joel Stanley <joel@jms.id.au> Signed-off-by: Joel Stanley <joel@jms.id.au> Link: https://lore.kernel.org/r/20200909222857.28653-2-eajames@linux.ibm.com Signed-off-by: Mark Brown <broonie@kernel.org>
2020-03-10spi: Add FSI-attached SPI controller driverEddie James
There exists a set of SPI controllers on some POWER processors that may be accessed through the FSI bus. Add a driver to traverse the FSI CFAM engine that can access and drive the SPI controllers. This driver would typically be used by a baseboard management controller (BMC). The SPI controllers operate by means of programming a sequencing engine which automatically manages the usual SPI protocol buses. The driver programs each transfer into the sequencer as various operations specifying the slave chip and shifting data in and out on the lines. Signed-off-by: Eddie James <eajames@linux.ibm.com> Link: https://lore.kernel.org/r/20200306194118.18581-3-eajames@linux.ibm.com Signed-off-by: Mark Brown <broonie@kernel.org>
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