Vladimir Oltean <vladimir.oltean@nxp.com>:
From: Vladimir Oltean <vladimir.oltean@nxp.com>
This series aims to remove the most inefficient transfer method from the
NXP DSPI driver.
TCFQ (Transfer Complete Flag) mode works by transferring one word,
waiting for its TX confirmation interrupt (or polling on the equivalent
status bit), sending the next word, etc, until the buffer is complete.
The issue with this mode is that it's fundamentally incompatible with
any sort of batching such as writing to a FIFO. But actually, due to
previous patchset ("Compatible string consolidation for NXP DSPI driver"):
https://patchwork.kernel.org/cover/11414593/
all existing users of TCFQ mode today already support a more advanced
feature set, in the form of XSPI (extended SPI). XSPI brings 2 extra
features:
- Word sizes up to 32 bits. This is sub-utilized today, and acceleration
of smaller-than-32 bpw values is provided.
- "Command cycling", basically the ability to write multiple words in a
row and receiving an interrupt only after the completion of the last
one. This is what enables us to make use of the full FIFO depth of
this controller.
Series was tested on the NXP LS1021A-TSN and LS1043A-RDB boards, both
functionally as well as from a performance standpoint.
The command used to benchmark the increased throughput was:
spidev_test --device /dev/spidev1.0 --bpw 8 --size 256 --cpha --iter 10000000 --speed 20000000
where spidev1.0 is a dummy spidev node, using a chip select that no
peripheral responds to.
On LS1021A, which has a 4-entry-deep FIFO and a less powerful CPU, the
performance increase brought by this patchset is from 2700 kbps to 5800
kbps.
On LS1043A, which has a 16-entry-deep FIFO and a more powerful CPU, the
performance increases from 4100 kbps to 13700 kbps.
On average, SPI software timestamping is not adversely affected by the
extra batching, due to the extra patches.
There is one extra patch which clarifies why the TCFQ users were not
converted to the "other" mode in this driver that makes use of the FIFO,
which would be EOQ mode.
My request to the many people on CC (known users and/or contributors) is
to give this series a test to ensure there are no regressions, and for
the Coldfire maintainers to clarify whether the EOQ limitation is
acceptable for them in the long run.
Vladimir Oltean (12):
spi: spi-fsl-dspi: Simplify bytes_per_word gymnastics
spi: spi-fsl-dspi: Remove unused chip->void_write_data
spi: spi-fsl-dspi: Don't mask off undefined bits
spi: spi-fsl-dspi: Add comments around dspi_pop_tx and dspi_push_rx
functions
spi: spi-fsl-dspi: Rename fifo_{read,write} and {tx,cmd}_fifo_write
spi: spi-fsl-dspi: Implement .max_message_size method for EOQ mode
spi: Do spi_take_timestamp_pre for as many times as necessary
spi: spi-fsl-dspi: Convert TCFQ users to XSPI FIFO mode
spi: spi-fsl-dspi: Accelerate transfers using larger word size if
possible
spi: spi-fsl-dspi: Optimize dspi_setup_accel for lowest interrupt
count
spi: spi-fsl-dspi: Use EOQ for last word in buffer even for XSPI mode
spi: spi-fsl-dspi: Take software timestamp in dspi_fifo_write
drivers/spi/spi-fsl-dspi.c | 421 ++++++++++++++++++++++++-------------
drivers/spi/spi.c | 19 +-
include/linux/spi/spi.h | 3 +-
3 files changed, 288 insertions(+), 155 deletions(-)
--
2.17.1
The SPI bus number is completely optional to Linux, so make the
corresponding device tree property optional as well.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Link: https://lore.kernel.org/r/20200305115546.31814-1-s.hauer@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>
Although the SPI system timestamps are supposed to reflect the moment
that the peripheral has received a word rather than the moment when the
CPU has enqueued that word to the FIFO, in practice it is easier to just
record the latter time than the former (with a smaller error).
With the recent migration of TCFQ users from poll back to interrupt mode
(this time for XSPI FIFO), it's wiser to keep the interrupt latency
outside of the measurement of the PTP system timestamp itself. If there
proves to be any constant offset that requires static compensation, that
can always be added later. So far that does not appear to be the case at
least on the LS1021A-TSN board, where testing shows that the phc2sys
offset is able to remain within +/- 200 ns even after 68 hours of
testing.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20200304220044.11193-13-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
The EOQ mode has a hardware limitation in that it stops the transmission
(including the deassertion of the chip select signal) once the host CPU
requests end-of-queue for a particular word in the TX FIFO.
And XSPI mode has a limitation in that we need a separate CMD FIFO entry
for the last byte in the buffer, where the chip select signal needs to
be deasserted. It's not a functional limitation, but it's rather clunky
and the fact that we need to halt the pipeline and write a single entry
to the TX FIFO whenever a buffer ends brings the throughput down when
transmitting small buffers.
So the idea here is to use EOQ's limitation in our favor when using XSPI
mode. Stop special-casing that final word in the buffer, and just kill
the chip select signal by issuing an EOQ for that last word. Now it can
be mixed in with all the other words in the current TX FIFO train.
A small trick here is that we still keep using the XSPI-specific
signaling via the CMDTCFQ interrupt in RSER, and not enabling the EOQ
interrupt, in order to avoid hardware weirdness (potential races with
separate interrupts being raised for CMDTCFQ and EOQ for what is in fact
the end of the same transmission). That is just theoretical, but it's
good to be cautious, and the EOQ interrupt isn't needed.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20200304220044.11193-12-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Currently, a SPI transfer that is not multiple of the highest supported
word width (e.g. 4 bytes) will be transmitted as follows (assume a
30-byte buffer transmitted through a 32-bit wide FIFO that is 32 bytes
deep):
- First 28 bytes are sent as 7 words of 32 bits each
- Last 2 bytes are sent as 1 word of 16 bits size
But if the dspi_setup_accel function had decided to use a lower
oper_bits_per_word value (16 instead of 32), there would have been
enough space in the TX FIFO to fit the entire buffer in one go (15 words
of 16 bits each).
What we're actually trying to avoid is mixing word sizes within the same
run with the TX FIFO, since there is an erratum surrounding this, and
invalid data might get transmitted.
So this patch adds special cases for when the remaining length of the
buffer can be sent in one go as 8-bit or 16-bit words, otherwise it
falls back to the standard logic of sending as many bytes as possible at
the highest oper_bits_per_word value possible.
The benefit is that there will be one less CMDFQ/EOQ interrupt to
service when the entire buffer is transmitted during a single go, and
that will improve the overall latency of the transfer.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20200304220044.11193-11-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This patch adds logic in the driver to transmit SPI buffers that use
bits_per_word=8 with a higher bits_per_word count (multiple of 8).
Currently the following (most common) modes are implemented:
- 8 bits_per_word on 32-bit capable controllers
- 8 bits_per_word on 16-bit capable controllers
- 16 bits_per_word on 32-bit capable controllers
Transfers which are not accelerated are transferred with a hardware
bits_per_word value equal to the one of the SPI transfer.
The difference from just extending bits_per_word=32 at the spi_device
driver level is that endianness is different - the SPI core wants to
treat bits_per_word=32 buffers as arrays of u32 (i.e. words in host CPU
endianness). So to preserve endianness when clumping 8x4 bits into
32-bit words, one must perform conversion between CPU and standard (big)
endianness.
All appearances (both on the wire as well as in the buffers presented to
the peripheral driver) are preserved, just that accesses to the PUSHR
and POPR registers are now more efficient, since the same number of
reads/writes can now carry more data (2x more data on TX, 4x more data
on RX).
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20200304220044.11193-10-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
The Transfer Complete Flag (TCF) interrupt gets raised after each write
to the TX FIFO (PUSHR) which means that it is not possible to devise a
transfer procedure that makes full utilization of the FIFO depth (4
entries on most controllers, 16 entries on some).
On the other hand, XSPI mode has a feature called "command cycling",
which allows a single TX command to be run for a pre-specified number of
TX words. When the command cycle ends, the Command Transfer Complete
Flag bit asserts and raises an interrupt. The advantage in this mode is
that the TX FIFO can be better utilized (more words can be batched at
once).
Other changes brought by this patch:
- The dspi->rx_end variable has been removed, since now the
dspi_fifo_write function sets up dspi->words_in_flight, so
dspi_fifo_read knows how much to read without overrunning the RX
buffer.
- Stop using poll mode unconditionally for TCFQ mode, since XSPI mode
is a little less efficient than that, and so, poll mode doesn't bring
as many improvements for XSPI.
- Stop relying on the hardware transfer counter (SPI_TCR_GET_TCNT) and
instead increment the message->actual_length based on the newly
introduced dspi->words_in_flight variable.
- The CTARE register is now written in the hotpath instead of just at
transfer init time, since it contains the DTCP field (transfer
preload - the counter indicating how many txdata words will follow),
which is a dynamic value.
Due to the fact that the Chip Select toggling setting is part of the
command written to the TX FIFO, the ending word of each buffer needs to
be sent via its own TX command, so that we have a chance to emit a
1-word command with deasserted PCS.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20200304220044.11193-9-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
When it gets set, End Of Queue Flag halts the DSPI controller and forces
the chip select signal to deassert.
This operating mode is not ideal, but it is used for the DSPI
instantiations where there is no other notification from the controller
that the data in the FIFO has finished transmission. So in practice, it
means that transmitting buffers larger than the FIFO size will yield
unpredictable results.
The only controller that operates in EOQ mode is MCF5441X (Coldfire). I
would say that the way EOQ is used (and documented in the reference
manual, too) on this chip is incorrect, and I would personally migrate
it to TCFQ, but that's notably worse in terms of performance (it can
only use 1 entry of the 16-deep FIFO) and if this limitation didn't
bother any Coldfire DSPI user so far, it's likely that we just need to
throw an error for larger buffers to make sure that callers are aware
their transfers are getting truncated/split.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20200304220044.11193-7-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
These function names are very generic and it is easy to get confused.
Rename them after the hardware register that they are accessing.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20200304220044.11193-6-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Their names are confusing, since dspi_pop_tx prepares a word to be
written to the PUSHR register, and dspi_push_rx gets a word from the
POPR register.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20200304220044.11193-5-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This is a useless operation, and if the driver needs to do that, there's
something deeply wrong going on.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20200304220044.11193-4-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This variable has been present since the initial submission of the
driver, and held, for some reason, the value of zero, to be sent on the
wire in the case there wasn't any TX buffer for the current transfer.
Since quite a while now, however, it isn't doing anything at all.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20200304220044.11193-3-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Reduce the if-then-else-if-then-else sequence to:
- a simple division in the case of bytes_per_word calculation
- a memcpy command with a variable size. The semantics of larger-than-8
xfer->bits_per_word is that those words are to be interpreted and
transmitted in CPU native endianness.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20200304220044.11193-2-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
The A-011218 eDMA/DSPI erratum affects most of the older Layerscape SoCs
with DSPI, and its workaround is a bit intrusive.
After this patch, there are no users of TCFQ mode that don't also
support XSPI (previously there was LS2085A).
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Message-Id: <20200302001958.11105-7-olteanv@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
There's no reason to keep this .ptp_sts_supported property explicitly in
devtype_data, since it can be deduced from the operating mode alone.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Message-Id: <20200302001958.11105-6-olteanv@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
XSPI allows for 2 extra features:
- Command cycling (use a single TX command with more than 1 word in the
TX FIFO).
- Increased word size (from 16 bits to 32 bits)
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Message-Id: <20200302001958.11105-5-olteanv@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Get rid of the ifdef for Coldfire and make these hardware
characteristics part of dspi->devtype_data.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Message-Id: <20200302001958.11105-4-olteanv@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Currently, the device tree bindings submitted in mainline for Layerscape
SoCs look like this:
LS1021A:
compatible = "fsl,ls1021a-v1.0-dspi";
LS1012A:
compatible = "fsl,ls1012a-dspi", "fsl,ls1021a-v1.0-dspi";
LS2085A:
compatible = "fsl,ls2085a-dspi";
LS2088A:
compatible = "fsl,ls2080a-dspi", "fsl,ls2085a-dspi";
LX2160A:
compatible = "fsl,lx2160a-dspi", "fsl,ls2085a-dspi";
LS1043A:
compatible = "fsl,ls1043a-dspi", "fsl,ls1021a-v1.0-dspi";
LS1046A:
compatible = "fsl,ls1021a-v1.0-dspi";
Due to a lack of a more specific compatible string, LS1012A, LS1043A and
LS1046A will fall under the LS1021A umbrella, and LS2088A and LX2160A
under the LS2085A umbrella.
They do work in those modes, but there are slight differences in the
hardware instantiations, mostly related to FIFO sizes (with the more
specific compatible strings, the FIFO size can be increased properly).
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Message-Id: <20200302001958.11105-3-olteanv@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
When used in Extended SPI mode on LS1021A, the DSPI controller wants to
have the least significant 16-bit word written first to the TX FIFO.
In fact, the LS1021A reference manual says:
33.5.2.4.2 Draining the TX FIFO
When Extended SPI Mode (DSPIx_MCR[XSPI]) is enabled, if the frame size
of SPI Data to be transmitted is more than 16 bits, then it causes two
Data entries to be popped from TX FIFO simultaneously which are
transferred to the shift register. The first of the two popped entries
forms the 16 least significant bits of the SPI frame to be transmitted.
So given the following TX buffer:
+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+
| 0x0 | 0x1 | 0x2 | 0x3 | 0x4 | 0x5 | 0x6 | 0x7 | 0x8 | 0x9 | 0xa | 0xb |
+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+
| 32-bit word 1 | 32-bit word 2 | 32-bit word 3 |
+-----------------------+-----------------------+-----------------------+
The correct way that a little-endian system should transmit it on the
wire when bits_per_word is 32 is:
0x03020100
0x07060504
0x0b0a0908
But it is actually transmitted as following, as seen with a scope:
0x01000302
0x05040706
0x09080b0a
It appears that this patch has been submitted at least once before:
https://lkml.org/lkml/2018/9/21/286
but in that case Chuanhua Han did not manage to explain the problem
clearly enough and the patch did not get merged, leaving XSPI mode
broken.
Fixes: 8fcd151d26 ("spi: spi-fsl-dspi: XSPI FIFO handling (in TCFQ mode)")
Cc: Esben Haabendal <eha@deif.com>
Cc: Chuanhua Han <chuanhua.han@nxp.com>
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20191228135536.14284-1-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
The API for PTP system timestamping (associating a SPI transaction with
the system time at which it was transferred) is flawed: it assumes that
the xfer->tx_buf pointer will always be present.
This is, of course, not always the case.
So introduce a "progress" variable that denotes how many word have been
transferred.
Fix the Freescale DSPI driver, the only user of the API so far, in the
same patch.
Fixes: b42faeee71 ("spi: Add a PTP system timestamp to the transfer structure")
Fixes: d6b71dfaee ("spi: spi-fsl-dspi: Implement the PTP system timestamping for TCFQ mode")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20191227012417.1057-1-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
dma_request_slave_channel() is a wrapper on top of dma_request_chan()
eating up the error code.
By using dma_request_chan() directly the driver can support deferred
probing against DMA.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Link: https://lore.kernel.org/r/20191212135550.4634-8-peter.ujfalusi@ti.com
Signed-off-by: Mark Brown <broonie@kernel.org>
For many places in the spi drivers, using the new `spi_transfer_delay`
helper is straightforward.
It's just replacing:
```
if (t->delay_usecs)
udelay(t->delay_usecs);
```
with `spi_transfer_delay(t)` which handles both `delay_usecs` and the new
`delay` field.
This change replaces in all places (in the spi drivers) where this change
is simple.
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-10-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>
In this mode, the DSPI controller uses PIO to transfer word by word. In
comparison, in EOQ mode the 4-word deep FIFO is being used, hence the
current logic will need some adaptation for which I do not have the
hardware (Coldfire) to test. It is not clear what is the timing of DMA
transfers and whether timestamping in the driver brings any overall
performance increase compared to regular timestamping done in the core.
Short phc2sys summary after 58 minutes of running on LS1021A-TSN with
interrupts disabled during the critical section:
offset: min -26251 max 16416 mean -21.8672 std dev 863.416
delay: min 4720 max 57280 mean 5182.49 std dev 1607.19
lost servo lock 3 times
Summary of the same phc2sys service running for 120 minutes with
interrupts disabled:
offset: min -378 max 381 mean -0.0083089 std dev 101.495
delay: min 4720 max 5920 mean 5129.38 std dev 154.899
lost servo lock 0 times
The minimum delay (pre to post time) in nanoseconds is the same, but the
maximum delay is quite a bit higher, due to interrupts getting sometimes
executed and interfering with the measurement. Hence set disable_irqs
whenever possible (aka when the driver runs in poll mode - otherwise it
would be a contradiction in terms).
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190905010114.26718-4-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
With this patch, the "interrupts" property from the device tree bindings
is ignored, even if present, if the driver runs in TCFQ mode.
Switching to using the DSPI in poll mode has several distinct
benefits:
- With interrupts, the DSPI driver in TCFQ mode raises an IRQ after each
transmitted word. There is more time wasted for the "waitq" event than
for actual I/O. And the DSPI IRQ count can easily get the largest in
/proc/interrupts on Freescale boards with attached SPI devices.
- The SPI I/O time is both lower, and more consistently so. Attached to
some Freescale devices are either PTP switches, or SPI RTCs. For
reading time off of a SPI slave device, it is important that all SPI
transfers take a deterministic time to complete.
- In poll mode there is much less time spent by the CPU in hardirq
context, which helps with the response latency of the system, and at
the same time there is more control over when interrupts must be
disabled (to get a precise timestamp measurement, which will come in a
future patch): win-win.
On the LS1021A-TSN board, where the SPI device is a SJA1105 PTP switch
(with a bits_per_word=8 driver), I created a "benchmark" where I
periodically transferred a 12-byte message once per second, for 120
seconds. I then recorded the time before putting the first byte in the
TX FIFO, and the time after reading the last byte from the RX FIFO. That
is the transfer delay in nanoseconds.
Interrupt mode:
delay: min 125120 max 168320 mean 150286 std dev 17675.3
Poll mode:
delay: min 69440 max 119040 mean 70312.9 std dev 8065.34
Both the mean latency and the standard deviation are more than 50% lower
in poll mode than in interrupt mode, and the 'max' in poll mode is lower
than the 'min' in interrupt mode. This is with an 'ondemand' governor on
an otherwise idle system - therefore running mostly at 600 MHz out of a
max of 1200 MHz.
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20191001205216.32115-1-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This change provides the dspi_slave_abort() function, which is a callback
for slave_abort() method of SPI controller generic driver.
As in the SPI slave mode the transmission is driven by master, any
distortion may cause the slave to enter undefined internal state.
To avoid this problem the dspi_slave_abort() terminates all pending and
ongoing DMA transactions (with sync) and clears internal FIFOs.
Signed-off-by: Lukasz Majewski <lukma@denx.de>
Link: https://lore.kernel.org/r/20190924110547.14770-3-lukma@denx.de
Signed-off-by: Mark Brown <broonie@kernel.org>
When the driver is working in TCFQ/EOQ mode (i.e. interacts with the SPI
controller's FIFOs directly) the following sequence of operations
happens:
- The first byte of the tx buffer gets pushed to the TX FIFO (dspi->len
gets decremented). This triggers the train of interrupts that handle
the rest of the bytes.
- The dspi_interrupt handles a TX confirmation event. It reads the newly
available byte from the RX FIFO, checks the dspi->len exit condition,
and if there's more to be done, it kicks off the next interrupt in the
train by writing the next byte to the TX FIFO.
Now the problem is that the wait queue is woken up one byte too early,
because dspi->len becomes 0 as soon as the byte has been pushed into the
TX FIFO. Its interrupt has not yet been processed and the RX byte has
not been put from the FIFO into the buffer.
Depending on the timing of the wait queue wakeup vs the handling of the
last dspi_interrupt, it can happen that the main SPI message pump thread
has already returned back into the spi_device driver. When the rx buffer
is on stack (which it can be, because in this mode, the DSPI doesn't do
DMA), the last interrupt will perform a memory write into an rx buffer
that has been freed. This manifests as stack corruption.
The solution is to only wake up the wait queue when dspi_rxtx says so,
i.e. after it has processed the last TX confirmation interrupt and
collected the last RX byte.
Fixes: c55be30591 ("spi: spi-fsl-dspi: Use poll mode in case the platform IRQ is missing")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190903105708.32273-1-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
On platforms like LS1021A which use TCFQ mode, an interrupt needs to be
processed after each byte is TXed/RXed. I tried to make the DSPI
implementation on this SoC operate in other, more efficient modes (EOQ,
DMA) but it looks like it simply isn't possible.
Therefore allow the driver to operate in poll mode, to ease a bit of
this absurd amount of IRQ load generated in TCFQ mode. Doing so reduces
both the net time it takes to transmit a SPI message, as well as the
inter-frame jitter that occurs while doing so.
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190822211514.19288-5-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
dspi->devtype_data is under the total control of the driver. Therefore,
a bad value is a driver bug and checking it at runtime (and during an
ISR, at that!) is pointless.
The second "else if" check is only for clarity (instead of a broader
"else") in case other transfer modes are added in the future. But the
printing is dead code and can be removed.
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190822211514.19288-4-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
The DSPI interrupt can be shared between two controllers at least on the
LX2160A. In that case, the driver for one controller might misbehave and
consume the other's interrupt. Fix this by actually checking if any of
the bits in the status register have been asserted.
Fixes: 13aed23927 ("spi: spi-fsl-dspi: use IRQF_SHARED mode to request IRQ")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190822211514.19288-3-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
If the entire function depends on the SPI status register having the
interrupt bits asserted, then just check it and exit early if those bits
aren't set (such as in the case of the shared IRQ being triggered for
the other peripheral). Cosmetic patch.
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190822211514.19288-2-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
The two functions are loosely coupled through dspi->waitq, but
logically, dspi_transfer_one_message depends on dspi_interrupt in order
to complete. Move its definition above it so the I/O functions are
grouped closer together.
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-13-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This patch puts variable declaration in the reverse order of their
length for cosmetic purposes.
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-11-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This adapts the spi-fsl-dspi driver to the API changes introduced in
commit 8caab75fd2 ("spi: Generalize SPI "master" to "controller"").
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-10-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Introduced in commit 9298bc7273 ("spi: spi-fsl-dspi: Remove
spi-bitbang") for less than obvious reasons, this assignment is
confusing and serves no purpose.
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-9-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
There is no code path for reaching 'return ret;' without it first being
assigned to an error code. Therefore the initialization with 0 is
pointless.
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-8-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
There is no point in surrounding an entire function block in an if
condition. Rather, exit early if the condition is false.
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-7-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
These are macros that accept 0 or 1 as argument (a boolean value). Their
use encourages the abuse of complex ternary operations inside their
argument list, which detracts from the code readability. Replace these
with simple if-else statements.
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-6-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This patch adds the field definitions for the SPI_SR register. The SPI
status register is write-1-to-clear and this value is written at init
time.
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-5-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Switch to using more idiomatic register field definitions, which makes
it easier to look them up in the datasheet. Cosmetic patch.
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-4-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This is a cosmetic patch that changes nothing except makes sure the code
is aligned to the same column, which makes it easier to the eye.
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-2-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
We don't need dev_err() messages when platform_get_irq() fails now that
platform_get_irq() prints an error message itself when something goes
wrong. Let's remove these prints with a simple semantic patch.
// <smpl>
@@
expression ret;
struct platform_device *E;
@@
ret =
(
platform_get_irq(E, ...)
|
platform_get_irq_byname(E, ...)
);
if ( \( ret < 0 \| ret <= 0 \) )
{
(
-if (ret != -EPROBE_DEFER)
-{ ...
-dev_err(...);
-... }
|
...
-dev_err(...);
)
...
}
// </smpl>
While we're here, remove braces on if statements that only have one
statement (manually).
Cc: Mark Brown <broonie@kernel.org>
Cc: linux-spi@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20190730181557.90391-42-swboyd@chromium.org
Signed-off-by: Mark Brown <broonie@kernel.org>
The NXP's Vybryd vf610 can work as a SPI slave device (the CS and clock
signals are provided by master).
It is possible to specify a single device to work in that mode. As we do
use DMA for transferring data, the RX channel must be prepared for
incoming data.
Moreover, in slave mode we just set a subset of control fields in
configuration registers (CTAR0, PUSHR).
For testing the spidev_test program has been used.
Test script for this patch can be found here:
https://github.com/lmajewski/tests-spi/blob/master/tests/spi/spi_tests.sh
Signed-off-by: Lukasz Majewski <lukma@denx.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
On ColdFire mcf54418, using DSPI_DMA_MODE mode, spi transfers
at first boot stage are not succeding:
m25p80 spi0.1: unrecognized JEDEC id bytes: 00, 00, 00
The reason is the SPI_SR initial value set by the driver, that
is not clearing (not setting to 1) the RF_DF flag. After a tour
on the dspi hw modules that use this driver(Vybrid, ColdFire and
ls1021a) a better init value for SR register has been set.
Signed-off-by: Angelo Dureghello <angelo@sysam.it>
Signed-off-by: Mark Brown <broonie@kernel.org>
Some SoC share one irq number between DSPI controllers.
For example, on the LX2160 board, DSPI0 and DSPI1 share one irq number.
In this case, only one DSPI controller can register successfully,
and others will fail.
Signed-off-by: Chuanhua Han <chuanhua.han@nxp.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
This patch fixes the dspi_eoq_write function used by the
ColdFire mcf5441x family. The 16 bit cmd part must be re-set at
each data transfer.
Also, now that fifo_size variables are used for eoq_read/write,
a proper fifo size must be set (16 slots for the ColdFire dspi
module version).
Signed-off-by: Angelo Dureghello <angelo@sysam.it>
Acked-by: Esben Haabendal <esben@haabendal.dk>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
Adopt the SPDX license identifier headers to ease license compliance
management.
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
