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: bbb6b2f986 ("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>
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>
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>
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: 9211a441e6 ("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>
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>
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: bbb6b2f986 ("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>
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: bbb6b2f986 ("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>
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>
The trailing <len> - 8 bytes of transfer data in this size range is no
longer ignored.
Fixes: bbb6b2f986 ("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>
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>
