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This patch implements the reporting of the effectively used speed_hz for
the transfer by setting xfer->effective_speed_hz.
See the following patch, which adds this feature to the SPI core for more
information:
commit 5d7e2b5ed5 ("spi: core: allow reporting the effectivly used speed_hz for a transfer")
Signed-off-by: Thomas Kopp <thomas.kopp@microchip.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20200921071036.2091-1-thomas.kopp@microchip.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Originally I intended to merge a dedicated Baikal-T1 System Boot SPI
Controller driver into the kernel and leave the DW APB SSI driver
untouched. But after a long discussion (see the link at the bottom of the
letter) Mark and Andy persuaded me to integrate what we developed there
into the DW APB SSI core driver to be useful for another controllers,
which may have got the same peculiarities/problems as ours:
- No IRQ.
- No DMA.
- No GPIO CS, so a native CS is utilized.
- small Tx/Rx FIFO depth.
- Automatic CS assertion/de-assertion.
- Slow system bus.
All of them have been fixed in the framework of this patchset in some
extent at least for the SPI memory operations. As I expected it wasn't
that easy and the integration took that many patches as you can see from
the subject. Though some of them are mere cleanups or weakly related with
the subject fixes, but we just couldn't leave the code as is at some
places since we were working with the DW APB SSI driver anyway. Here is
what we did to fix the original DW APB SSI driver, to make it less messy.
First two patches are just cleanups to simplify the DW APB SSI device
initialization a bit. We suggest to discard the IRQ threshold macro as
unused and use a ternary operator to initialize the set_cs callback
instead of assigning-and-updating it.
Then we've discovered that the n_bytes field of the driver private data is
used by the DW APB SSI IRQ handler, which requires it to be initialized
before the SMP memory barrier and to be visible from another CPUs. Speaking
about the SMP memory barrier. Having one right after the shared resources
initialization is enough and there is no point in using the spin-lock to
protect the Tx/Rx buffer pointers. The protection functionality is
redundant there by the driver design. (Though I have a doubt whether the
SMP memory barrier is also required there because the normal IO-methods
like readl/writel implies a full memory barrier. So any memory operations
performed before them are supposed to be seen by devices and another CPUs.
See the patch log for details of my concern.)
Thirdly we've found out that there is some confusion in the IRQs
masking/unmasking/clearing in the SPI-transfer procedure. Multiple interrupts
are unmasked on the SPI-transfer initialization, but just TXEI is only
masked back on completion. Similarly IRQ status isn't cleared on the
controller reset, which actually makes the reset being not full and errors
prone in the controller probe procedure.
Another very important optimization is using the IO-relaxed accessors in
the dw_read_io_reg()/dw_write_io_reg() methods. Since the Tx/Rx FIFO data
registers are the most frequently accessible controller resource, using
relaxed accessors there will significantly improve the data read/write
performance. At least on Baikal-T1 SoC such modification opens up a way to
have the DW APB SSI controller working with higher SPI bus speeds, than
without it.
Fifthly we've made an effort to cleanup the code using the SPI-device
private data - chip_data. We suggest to remove the chip type from there
since it isn't used and isn't implemented right anyway. Then instead of
having a bus speed, clock divider, transfer mode preserved there, and
recalculating the CR0 fields of the SPI-device-specific phase, polarity
and frame format each time the SPI transfer is requested, we can save it
in the chip_data instance. By doing so we'll make that structure finally
used as it was supposed to by design (see the spi-fsl-dspi.c, spi-pl022.c,
spi-pxa2xx.c drivers for examples).
Sixthly instead of having the SPI-transfer specific CR0-update callback,
we suggest to implement the DW APB SSI controller capabilities approach.
By doing so we can now inject the vendor-specific peculiarities in
different parts of the DW APB SSI core driver (which is required to
implement both SPI-transfers and the SPI memory operations). This will
also make the code less confusing like defining a callback in the core
driver, setting it up in the glue layer, then calling it from the core
driver again. Seeing the small capabilities implementation embedded
in-situ is more readable than tracking the callbacks assignments. This
will concern the CS-override, Keembay master setup, DW SSI-specific CR0
registers layout capabilities.
Seventhly since there are going to be two types of the transfers
implemented in the DW APB SSI core driver, we need a common method to set
the controller configuration like, Tx/Rx-mode, bus speed, data frame size
and number of data frames to read in case of the memory operations. So we
just detached the corresponding code from the SPI-transfer-one method and
made it to be a part of the new dw_spi_update_config() function, which is
former update_cr0(). Note that the new method will be also useful for the
glue drivers, which due to the hardware design need to create their own
memory operations (for instance, for the dirmap-operations provided in the
Baikal-T System Boot SPI controller driver).
Eighthly it is the data IO procedure and IRQ-based SPI-transfer
implementation refactoring. The former one will look much simpler if the
buffers initial pointers and the buffers length data utilized instead of
the Tx/Rx buffers start and end pointers. The later one currently lacks of
valid execution at the final stage of the SPI-transfer. So if there is no
data left to send, but there is still data which needs to be received, the
Tx FIFO Empty IRQ will constantly happen until all of the requested
inbound data is received. So we suggest to fix that by taking the Rx FIFO
Empty IRQ into account.
Ninthly it's potentially errors prone to enable the DW APB SSI interrupts
before enabling the chip. It specifically concerns a case if for some
reason the DW APB SSI IRQs handler is executed before the controller is
enabled. That will cause a part of the outbound data loss. So we suggest
to reverse the order.
Tenthly in order to be able to pre-initialize the Tx FIFO with data and
only the start the SPI memory operations we need to have any CS
de-activated. We'll fulfil that requirement by explicitly clearing the CS
on the SPI transfer completion and at the explicit controller reset.
Then seeing all the currently available and potentially being created
types of the SPI transfers need to perform the DW APB SSI controller
status register check and the errors handler procedure, we've created a
common method for all of them.
Eleventhly if before we've mostly had a series of fixups, cleanups and
refactorings, here we've finally come to the new functionality
implementation. It concerns the poll-based transfer (as Baikal-T1 System
Boot SPI controller lacks a dedicated IRQ lane connected) and the SPI
memory operations implementation. If the former feature is pretty much
straightforward (see the patch log for details), the later one is a bit
tricky. It's based on the EEPROM-read (write-then-read) and the Tx-only
modes of the DW APB SSI controller, which as performing the automatic data
read and write let's us to implement the faster IO procedure than using
the Tx-Rx-mode-based approach. Having the memory-operations implemented
that way is the best thing we can currently do to provide the errors-less
SPI transfers to SPI devices with native CS attached.
Note the approach utilized here to develop the SPI memory operations can
be also used to create the "automatic CS toggle problem"-free(ish) SPI
transfers (combine SPI-message transfers into two buffers, disable
interrupts, push-pull the combined data). But we don't provide a solution
in the framework of this patchset. It is a matter of a dedicated one,
which we currently don't intend to spend our time on.
Finally at the closure of the this patchset you'll find patches, which
provide the Baikal-T1-specific DW APB SSI controllers support. The SoC has
got three SPI controllers. Two of them are pretty much normal DW APB SSI
interfaces: with IRQ, DMA, FIFOs of 64 words depth, 4x CSs. But the third
one as being a part of the Baikal-T1 System Boot Controller has got a very
limited resources: no IRQ, no DMA, only a single native chip-select and
Tx/Rx FIFOs with just 8 words depth available. In order to provide a
transparent initial boot code execution the System Boot SPI Controller is
also utilized by an vendor-specific IP-block, which exposes an SPI flash
memory direct mapping interface. Please see the corresponding patch for
details.
Link: https://lore.kernel.org/linux-spi/20200508093621.31619-1-Sergey.Semin@baikalelectronics.ru/
[1] "LINUX KERNEL MEMORY BARRIERS", Documentation/memory-barriers.txt,
Section "KERNEL I/O BARRIER EFFECTS"
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Ramil Zaripov <Ramil.Zaripov@baikalelectronics.ru>
Cc: Pavel Parkhomenko <Pavel.Parkhomenko@baikalelectronics.ru>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Lars Povlsen <lars.povlsen@microchip.com>
Cc: wuxu.wu <wuxu.wu@huawei.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: linux-spi@vger.kernel.org
Cc: devicetree@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Serge Semin (30):
spi: dw: Discard IRQ threshold macro
spi: dw: Use ternary op to init set_cs callback
spi: dw: Initialize n_bytes before the memory barrier
Revert: spi: spi-dw: Add lock protect dw_spi rx/tx to prevent
concurrent calls
spi: dw: Clear IRQ status on DW SPI controller reset
spi: dw: Disable all IRQs when controller is unused
spi: dw: Use relaxed IO-methods to access FIFOs
spi: dw: Discard DW SSI chip type storages
spi: dw: Convert CS-override to DW SPI capabilities
spi: dw: Add KeemBay Master capability
spi: dw: Add DWC SSI capability
spi: dw: Detach SPI device specific CR0 config method
spi: dw: Update SPI bus speed in a config function
spi: dw: Simplify the SPI bus speed config procedure
spi: dw: Update Rx sample delay in the config function
spi: dw: Add DW SPI controller config structure
spi: dw: Refactor data IO procedure
spi: dw: Refactor IRQ-based SPI transfer procedure
spi: dw: Perform IRQ setup in a dedicated function
spi: dw: Unmask IRQs after enabling the chip
spi: dw: Discard chip enabling on DMA setup error
spi: dw: De-assert chip-select on reset
spi: dw: Explicitly de-assert CS on SPI transfer completion
spi: dw: Move num-of retries parameter to the header file
spi: dw: Add generic DW SSI status-check method
spi: dw: Add memory operations support
spi: dw: Introduce max mem-ops SPI bus frequency setting
spi: dw: Add poll-based SPI transfers support
dt-bindings: spi: dw: Add Baikal-T1 SPI Controllers
spi: dw: Add Baikal-T1 SPI Controller glue driver
.../bindings/spi/snps,dw-apb-ssi.yaml | 33 +-
drivers/spi/Kconfig | 29 +
drivers/spi/Makefile | 1 +
drivers/spi/spi-dw-bt1.c | 339 +++++++++
drivers/spi/spi-dw-core.c | 642 ++++++++++++++----
drivers/spi/spi-dw-dma.c | 16 +-
drivers/spi/spi-dw-mmio.c | 36 +-
drivers/spi/spi-dw.h | 85 ++-
8 files changed, 960 insertions(+), 221 deletions(-)
create mode 100644 drivers/spi/spi-dw-bt1.c
--
2.27.0
There is no point in having the commit 19b61392c5 ("spi: spi-dw: Add
lock protect dw_spi rx/tx to prevent concurrent calls") applied. The
commit author made an assumption that the problem with the rx data
mismatch was due to the lack of the data protection. While most likely it
was caused by the lack of the memory barrier. So having the
commit bfda044533 ("spi: dw: use "smp_mb()" to avoid sending spi data
error") applied would be enough to fix the problem.
Indeed the spin unlock operation makes sure each memory operation issued
before the release will be completed before it's completed. In other words
it works as an implicit one way memory barrier. So having both smp_mb()
and the spin_unlock_irqrestore() here is just redundant. One of them would
be enough. It's better to leave the smp_mb() since the Tx/Rx buffers
consistency is provided by the data transfer algorithm implementation:
first we initialize the buffers pointers, then make sure the assignments
are visible by the other CPUs by calling the smp_mb(), only after that
enable the interrupt, which handler uses the buffers.
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20200920112914.26501-5-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Mark Brown <broonie@kernel.org>
In a further commit we'll have to get rid of the update_cr0() callback and
define a DW SSI capability instead. Since Keem Bay master/slave
functionality is controller by the CTRL0 register bitfield, we need to
first move the master mode selection into the internal corresponding
update_cr0 method, which would be activated by means of the dedicated
DW_SPI_CAP_KEEMBAY_MST capability setup.
Note this will be also useful if the driver will be ever altered to
support the DW SPI slave interface.
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20200920112914.26501-11-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Mark Brown <broonie@kernel.org>
There are several vendor-specific versions of the DW SPI controllers,
each of which may have some peculiarities with respect to the original
IP-core. Seeing it has already caused adding flags and a callback into the
DW SPI private data, let's introduce a generic capabilities interface to
tune the generic DW SPI controller driver up in accordance with the
particular controller specifics. It's done by converting a simple
Alpine-specific CS-override capability into the DW SPI controller
capability activated by setting the DW_SPI_CAP_CS_OVERRIDE flag.
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20200920112914.26501-10-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Mark Brown <broonie@kernel.org>
Keeping SPI peripheral devices type is pointless since first it hasn't
been functionally utilized by any of the client drivers/code and second it
won't work for Microwire type at the very least. Moreover there is no
point in setting up the type by means of the chip-data in the modern
kernel. The peripheral devices with specific interface type need to be
detected in order to activate the corresponding frame format. It most
likely will require some peripheral device specific DT property or
whatever to find out the interface protocol. So let's remove the serial
interface type fields from the DW APB SSI controller and the SPI
peripheral device private data.
Note we'll preserve the explicit SSI_MOTO_SPI interface type setting up to
signify the only currently supported interface protocol.
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20200920112914.26501-9-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Mark Brown <broonie@kernel.org>
In accordance with [1] the relaxed methods are guaranteed to be ordered
with respect to other accesses from the same CPU thread to the same
peripheral. This is what we need during the data read/write from/to the
controller FIFOs being executed within a single IRQ handler or a kernel
task.
Such optimization shall significantly speed the data reader and writer up.
For instance, the relaxed IO-accessors utilization on Baikal-T1 lets the
driver to support the SPI memory operations with bus frequency three-fold
faster than if normal IO-accessors would be used.
[1] "LINUX KERNEL MEMORY BARRIERS", Documentation/memory-barriers.txt,
Section "KERNEL I/O BARRIER EFFECTS"
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20200920112914.26501-8-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Mark Brown <broonie@kernel.org>
It's a good practice to disable all IRQs if a device is fully unused. In
our case it is supposed to be done before requesting the IRQ and after the
last byte of an SPI transfer is received. In the former case it's required
to prevent the IRQ handler invocation before the driver data is fully
initialized (which may happen if the IRQs status has been left uncleared
before the device is probed). So we just moved the spi_hw_init() method
invocation to the earlier stage before requesting the IRQ. In the later
case there is just no point in having any of the IRQs enabled between SPI
transfers and when there is no SPI message currently being processed.
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20200920112914.26501-7-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Mark Brown <broonie@kernel.org>
It turns out the IRQ status isn't cleared after switching the controller
off and getting it back on, which may cause raising false error interrupts
if controller has been unsuccessfully used by, for instance, a bootloader
before the driver is loaded. Let's explicitly clear the interrupts status
in the dedicated controller reset method.
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20200920112914.26501-6-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Mark Brown <broonie@kernel.org>
Since n_bytes field of the DW SPI private data is also utilized by the
IRQ handler, we need to make sure it' initialization is done before the
memory barrier.
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20200920112914.26501-4-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Mark Brown <broonie@kernel.org>
In case if at least one of the requested DMA engine channels doesn't
support the hardware accelerated SG list entries traverse, the DMA driver
will most likely work that around by performing the IRQ-based SG list
entries resubmission. That might and will cause a problem if the DMA Tx
channel is recharged and re-executed before the Rx DMA channel. Due to
non-deterministic IRQ-handler execution latency the DMA Tx channel will
start pushing data to the SPI bus before the Rx DMA channel is even
reinitialized with the next inbound SG list entry. By doing so the DMA
Tx channel will implicitly start filling the DW APB SSI Rx FIFO up, which
while the DMA Rx channel being recharged and re-executed will eventually
be overflown.
In order to solve the problem we have to feed the DMA engine with SG
list entries one-by-one. It shall keep the DW APB SSI Tx and Rx FIFOs
synchronized and prevent the Rx FIFO overflow. Since in general the SPI
tx_sg and rx_sg lists may have different number of entries of different
lengths (though total length should match) we virtually split the
SG-lists to the set of DMA transfers, which length is a minimum of the
ordered SG-entries lengths.
The solution described above is only executed if a full-duplex SPI
transfer is requested and the DMA engine hasn't provided channels with
hardware accelerated SG list traverse capability to handle both SG
lists at once.
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200920112322.24585-12-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Mark Brown <broonie@kernel.org>
In order to use the DMA submission and waiting methods in both generic
DMA-based SPI transfer and one-by-one DMA SG entries transmission
functions, we need to modify the dw_spi_dma_wait() and
dw_spi_dma_submit_tx()/dw_spi_dma_submit_rx() prototypes. So instead of
getting the SPI transfer object as the second argument they must accept
the exact data structure instances they imply to use. Those are the
current transfer length and the SPI bus frequency in case of
dw_spi_dma_wait(), and SG list together with number of list entries in
case of the DMA Tx/Rx submission methods.
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20200920112322.24585-11-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Mark Brown <broonie@kernel.org>
DW APB SSI DMA driver doesn't use the native SPI core wait API since
commit bdbdf0f063 ("spi: dw: Locally wait for the DMA transfers
completion"). Due to that the driver can now clear the DMAC register
in a single place synchronously with the DMA transactions completion
or failure. After that all the possible code paths are still covered:
1) DMA completion callbacks are executed in case if the corresponding DMA
transactions are finished. When they are, one of them will eventually wake
the SPI messages pump kernel thread and dw_spi_dma_transfer_all() method
will clean the DMAC register as implied by this patch.
2) dma_stop is called when the SPI core detects an error either returned
from the transfer_one() callback or set in the SPI message status field.
Both types of errors will be noticed by the dw_spi_dma_transfer_all()
method.
3) dma_exit is called when either SPI controller driver or the
corresponding device is removed. In any case the SPI core will first
flush the SPI messages pump kernel thread, so any pending or in-fly
SPI transfers will be finished before that.
Due to all of that let's simplify the DW APB SSI DMA driver a bit and
move the DMAC register cleanup to a single place in the
dw_spi_dma_transfer_all() method.
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20200920112322.24585-10-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Mark Brown <broonie@kernel.org>
In order to add an alternative method of DMA-based SPI transfer first we
need to detach the currently available one from the common code. Here we
move the normal DMA-based SPI transfer execution functionality into a
dedicated method. It will be utilized if either the DMA engine supports
an unlimited number SG entries or Tx-only SPI transfer is requested. But
currently just use it for any SPI transfer.
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20200920112322.24585-9-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Mark Brown <broonie@kernel.org>
It's pointless to pass the Rx and Tx transfers DMA Tx-descriptors, since
they are used in the Tx/Rx submit method only. Instead just return the
submission status from these methods. This alteration will make the code
less complex.
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20200920112322.24585-8-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Mark Brown <broonie@kernel.org>
We suggest to add the dmaengine_submit() return value test for errors. It
has been unnecessary while the driver was expected to be utilized in pair
with DW DMAC. But since now the driver can be used with any DMA engine, it
might be useful to track the errors on DMA submissions so not miss them
and get into an unpredictable driver behaviour.
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20200920112322.24585-7-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Mark Brown <broonie@kernel.org>
Indeed we can freely move the dmaengine_submit() method invocation and the
Tx and Rx busy flag setting into the DMA Tx/Rx prepare methods. Since the
Tx/Rx preparation method is now mainly used for the DMA transfers
submission, here we suggest to rename it to have the _submit_{r,t}x suffix
instead.
By having this alteration applied first we implement another code
preparation before adding the one-by-one DMA SG entries transmission,
second we now have the dma_async_tx_descriptor descriptor used locally
only in the new DMA transfers submission methods (this will be cleaned up
a bit later), third we make the generic transfer method more readable,
where now the functionality of submission, execution and wait procedures
is transparently split up instead of having a preparation, intermixed
submission/execution and wait procedures.
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20200920112322.24585-6-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Mark Brown <broonie@kernel.org>
Checking rx_buf for being NULL and returning NULL from the Rx-channel
preparation method doesn't let us to distinguish that situation from
errors happening during the Rx SG-list preparation. So it's better to make
sure that the rx_buf not-NULL and full-duplex communication is requested
prior calling the Rx preparation method.
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20200920112322.24585-5-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Mark Brown <broonie@kernel.org>
Mainly this is a preparation patch before adding one-by-one DMA SG entries
transmission. But logically the Tx and Rx DMA channels setup should be
performed in the dma_setup() callback anyway. So we'll move the DMA slave
channels src/dst burst lengths, address and address width configuration
from the Tx/Rx channels preparation methods to the dedicated functions and
then make sure it's called at the DMA setup stage.
Note we now make sure the return value of the dmaengine_slave_config()
method doesn't indicate an error. It has been unnecessary in case if Dw
DMAC is utilized as a DMA engine, since its device_config() callback
always returns zero (though it might change in future). But since DW APB
SSI driver now supports any DMA back-end we must make sure the DMA device
configuration has been successful before proceeding with further setups.
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20200920112322.24585-4-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Mark Brown <broonie@kernel.org>
Since commit 46164fde6b ("spi: dw: Fix Rx-only DMA transfers") if DMA
interface is enabled, then Tx-buffer must be available in each SPI
transfer. It's required since in order to activate the incoming data
reception either DMA or CPU must be pushing data out to the SPI bus.
But the DW APB SSI DMA driver code is still left in state as if Tx-buffer
might be optional, which is no longer true. Let's fix it so an error would
be returned if no Tx-buffer detected and DMA Tx would be always
enabled.
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20200920112322.24585-3-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Mark Brown <broonie@kernel.org>
Indeed the registers content doesn't get cleared when the SPI controller
is disabled and enabled. Max burst lengths aren't changed since the Rx and
Tx DMA channels are requested on init stage and are kept acquired until
the device is removed. Obviously SPI controller FIFO depth can't be
changed. Due to all of that we can safely move the DMA Transmit and
Receive data level registers initialization to the SPI controller DMA init
stage (when the SPI controller is being probed) instead of doing it for
each SPI transfer when dma_setup is called. This shall speed the DMA-based
SPI transfer initialization up a bit, particularly if the APB bus is
relatively slow.
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20200920112322.24585-2-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Mark Brown <broonie@kernel.org>
This series mainly add the IRQ mode support for hisi-sfc-v3xx driver, and some
cleanups for the preparation of the IRQ mode.
After this patch, the device can work in IRQ mode, or if firmware doesn't
declare irq support it will fall back to Poll mode.
Patch 1-2 refactor the .exec_op() path to make it simpler and clearer.
Patch 3 factor the definition of the interrupt bits.
Patch 4 add the IRQ support of the driver.
Yicong Yang (4):
spi: hisi-sfc-v3xx: factor out IO modes configuration
spi: hisi-sfc-v3xx: factor out bus config and transfer functions
spi: hisi-sfc-v3xx: factor out the bit definition of interrupt
register
spi: hisi-sfc-v3xx: add support for IRQ mode
drivers/spi/spi-hisi-sfc-v3xx.c | 261 +++++++++++++++++++++++++++++-----------
1 file changed, 190 insertions(+), 71 deletions(-)
--
2.8.1
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CLK_TO_US macro is used to calculate potential transfer time for various
timeout handling. However it overflows on transfer bigger than 512 bytes
because it first did (len * 8 * 1000000).
This controller typically operates at 45MHz. This patch did 2 things:
1. calculate clock / 1000000 first
2. add a 4M transfer size cap so that the final timeout in DMA reading
doesn't overflow
Fixes: 881d1ee9fe ("spi: add support for mediatek spi-nor controller")
Cc: <stable@vger.kernel.org>
Signed-off-by: Chuanhong Guo <gch981213@gmail.com>
Link: https://lore.kernel.org/r/20200922114905.2942859-1-gch981213@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
The controller can work with interrupts, so add support for it.
Then we can work under IRQ mode or Poll mode now, if firmware
doesn't declare the IRQ support, it will fall back to Poll mode.
Acked-by: John Garry <john.garry@huawei.com>
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Link: https://lore.kernel.org/r/1600950270-52536-5-git-send-email-yangyicong@hisilicon.com
Signed-off-by: Mark Brown <broonie@kernel.org>
The definition of the register field in the interrupt corresponding
registers are the same. So factor them out to public place.
Acked-by: John Garry <john.garry@huawei.com>
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Link: https://lore.kernel.org/r/1600950270-52536-4-git-send-email-yangyicong@hisilicon.com
Signed-off-by: Mark Brown <broonie@kernel.org>
In hisi_sfc_v3xx_generic_exec_op(), we will write the data to the buffer,
configure and start the transfer, read the data to the buffer and check
whether occurs an error. Factor out the config and transfer start codes
as individual functions, to make the process a bit clearer.
Acked-by: John Garry <john.garry@huawei.com>
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Link: https://lore.kernel.org/r/1600950270-52536-3-git-send-email-yangyicong@hisilicon.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Factor IO modes configuration out of hisi_sfc_v3xx_generic_exec_op()
using an IO modes lookup table. This will make the process a bit clearer
and reduce the cyclomatic complexity. Simplify the IO mode definition
macros a little bit as well.
Also add the .supports_op() method for the controller mem ops, in order
to avoid OOB access.
Acked-by: John Garry <john.garry@huawei.com>
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Link: https://lore.kernel.org/r/1600950270-52536-2-git-send-email-yangyicong@hisilicon.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This patch implementes the reporting of the effectivly used speed_hz for the
transfer by setting tfr->effective_speed_hz.
See the following patch, which adds this feature to the SPI core for more
information:
5d7e2b5ed5 spi: core: allow reporting the effectivly used speed_hz for a transfer
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Link: https://lore.kernel.org/r/20200917202420.1914104-1-mkl@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>
This reverts commit 13d515c796 (spi: omap2-mcspi: Switch to
readl_poll_timeout()).
The amount of time spent polling for the MCSPI_CHSTAT bits to be set on
AM335x-icev2 platform is less than 1us (about 0.6us) in most cases, with
or without using DMA. So, in most cases the function need not sleep.
Also, setting the sleep_usecs to zero would not be optimal here because
ktime_add_us() used in readl_poll_timeout() is slower compared to the
direct addition used after the revert. So, it is sub-optimal to use
readl_poll_timeout in this case.
When DMA is not enabled, this revert results in an increase of about 27%
in throughput and decrease of about 20% in CPU usage. However, the CPU
usage and throughput are almost the same when used with DMA.
Therefore, fix this by reverting the commit which switched to using
readl_poll_timeout().
Fixes: 13d515c796 ("spi: omap2-mcspi: Switch to readl_poll_timeout()")
Signed-off-by: Aswath Govindraju <a-govindraju@ti.com>
Link: https://lore.kernel.org/r/20200910122624.8769-1-a-govindraju@ti.com
Signed-off-by: Mark Brown <broonie@kernel.org>
sg_init_table zeroes its first argument, so the allocation of that argument
doesn't have to.
the semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)
// <smpl>
@@
expression x,n,flags;
@@
x =
- kcalloc
+ kmalloc_array
(n,sizeof(*x),flags)
...
sg_init_table(x,n)
// </smpl>
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Link: https://lore.kernel.org/r/1600601186-7420-12-git-send-email-Julia.Lawall@inria.fr
Signed-off-by: Mark Brown <broonie@kernel.org>
This series implements a number of fixes for the FSI-attached SPI
controller driver.
Changes since v1:
- Switch to a new compatible string for the restricted version of the
SPI controller, rather than a new boolean parameter.
Brad Bishop (3):
spi: fsi: Handle 9 to 15 byte transfers lengths
spi: fsi: Fix clock running too fast
spi: fsi: Fix use of the bneq+ sequencer instruction
Eddie James (3):
dt-bindings: fsi: fsi2spi: Add compatible string for restricted
version
spi: fsi: Implement restricted size for certain controllers
spi: fsi: Check mux status before transfers
.../devicetree/bindings/fsi/ibm,fsi2spi.yaml | 1 +
drivers/spi/spi-fsi.c | 139 ++++++++++++++----
2 files changed, 109 insertions(+), 31 deletions(-)
--
2.26.2
Free previously allocated IRQs when return an error code of desc->setup()
which is not always successful. And simplify the code by adding a goto
label.
Fixes: 8f5c285f3e ("SPI: designware: pci: Switch over to MSI interrupts")
CC: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Jay Fang <f.fangjian@huawei.com>
Link: https://lore.kernel.org/r/1600132969-53037-1-git-send-email-f.fangjian@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Currently NXP fspi driver has support of DT only. Adding ACPI
support to the driver so that it can be used by UEFI firmware
booting in ACPI mode. This driver will be probed if any firmware
will expose HID "NXP0009" in DSDT table.
Signed-off-by: kuldip dwivedi <kuldip.dwivedi@puresoftware.com>
Reviewed-by: Ashish Kumar <Ashish.Kumar@nxp.com>
Link: https://lore.kernel.org/r/20200911130331.6313-1-kuldip.dwivedi@puresoftware.com
Signed-off-by: Mark Brown <broonie@kernel.org>
The info message was showing the mapped address of the device. To avoid
security problems, all virtual addresses are converted to __ptrval__, so
the message was useless/ugly:
[ 2.304949] xilinx_spi b0010000.spi-flash: at 0xB0010000 mapped to 0x(____ptrval____), irq=37
Use %pR instead:
[ 15.021354] xilinx_spi b0010000.spi-flash: at [mem 0xb0010000-0xb001ffff], irq=37
Signed-off-by: Ricardo Ribalda <ribalda@kernel.org>
Acked-by: Michal Simek <michal.simek@xilinx.com>
Link: https://lore.kernel.org/r/20200915112936.320647-1-ribalda@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Add a compatible string for the restricted version of the SPI controller.
The restricted version cannot process sequence loop operations and
therefore has a smaller transfer size.
Signed-off-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20200909222857.28653-5-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>
Common pattern of handling deferred probe can be simplified with
dev_err_probe(). Less code and the error value gets printed.
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Chunyan Zhang <zhang.lyra@gmail.com>
Link: https://lore.kernel.org/r/20200910160706.5883-1-krzk@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
If we're sending bytes over SPI, we know the FIFO is empty at the
start of the transfer. There's no reason to wait for the interrupt
telling us to start--we can just start right away. Then if we
transmit everything in one swell foop we don't even need to bother
listening for TX interrupts.
In a test of "flashrom -p ec -r /tmp/foo.bin" interrupts were reduced
from ~30560 to ~29730, about a 3% savings.
This patch looks bigger than it is because I moved a few functions
rather than adding a forward declaration. The only actual change to
geni_spi_handle_tx() was to make it return a bool indicating if there
is more to tx.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Akash Asthana <akashast@codeaurora.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20200912111716.1.Ied5e843fad0d6b733a1fb8bcfb364dd2fa889eb3@changeid
Signed-off-by: Mark Brown <broonie@kernel.org>
This eliminates the following sparse warning:
drivers/spi/spi-bcm2835.c:78:14: warning: symbol 'polling_limit_us' was
not declared. Should it be static?
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Link: https://lore.kernel.org/r/20200912072211.602735-1-yanaijie@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>
