Commit Graph

54 Commits

Author SHA1 Message Date
Ricardo Ribalda Delgado eca37c7c11 spi/spi-xilinx: Fix race condition on last word read
Some users have reported that in polled mode the driver fails randomly
to read the last word of the transfer.

The end condition used for the transmissions (in polled and irq mode)
has been the TX_EMPTY flag. But Lars-Peter Clausen has identified a delay
from the TX_EMPTY to the actual end of the data rx.

I believe that this race condition has not been detected until now
because of the latency added by the IRQ handler or the PCIe bridge.
This bugs affects setups with low latency access to the spi core.

This patch replaces the readout logic:

For all the words, except the last one, the TX_EMPTY flag is used (and
cached).

If !TX_EMPY or is the last word. The status register is read and the
RX_EMPTY flag is used.

The performance is not affected: there is an extra read of the
Status Register, but the readout can start as soon as there is a word
in the buffer.

Reported-by: Edward Kigwana <ekigwana@scires.com>
Initial-fix-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
2015-10-29 09:03:42 +09:00
Ricardo Ribalda Delgado 74346841e6 spi/spi-xilinx: Fix spurious IRQ ACK on irq mode
The ACK of an inexistent IRQ can trigger an spurious IRQ that breaks the
txrx logic. This has been observed on axi_quad_spi:3.2 core.

This patch only ACKs IRQs that have not been Acknowledge jet.

Reported-by: Edward Kigwana <ekigwana@scires.com>
Tested-by: Edward Kigwana <ekigwana@scires.com>
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
2015-08-14 16:35:19 +01:00
Ricardo Ribalda Delgado 16ea9b8ac4 spi/spi-xilinx: Fix mixed poll/irq mode
Once the module process a transfer in irq mode, the next poll transfer
will not work because the transmitter is left in inhibited state.

Fixes: 22417352f6 (Use polling mode on small transfers)
Reported-by: Edward Kigwana <ekigwana@scires.com>
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
2015-08-13 12:29:23 +01:00
Ricardo Ribalda Delgado 34093cb97a spi/xilinx: Fix access invalid memory on xilinx_spi_tx
On 1 and 2 bytes per word, the transfer of the 3 last bytes will access
memory outside tx_ptr.

Although this has not trigger any error on real hardware, we should
better fix this.

Fixes: 24ba5e593f (Remove rx_fn and tx_fn pointer)
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-02-02 12:17:19 +00:00
Mark Brown 0635287a30 spi: Revert "spi/xilinx: Remove iowrite/ioread wrappers"
This reverts commit 99082eab63 since it
breaks the build due to differing implementations of iowrite() and
ioread().

Signed-off-by: Mark Brown <broonie@kernel.org>
2015-01-30 13:42:00 +01:00
Ricardo Ribalda eb25f16c6f spi/xilinx: Check number of slaves range
The core only supports up to 32 slaves, and the chipselect function
expects the same.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-01-28 19:57:32 +00:00
Ricardo Ribalda Delgado 22417352f6 spi/xilinx: Use polling mode on small transfers
Small transfers generally can be accomplished faster in polling mode.
This patch select the transfer which size is bellow the buffer size to
be done on polling mode

Suggested-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-01-28 19:42:43 +00:00
Ricardo Ribalda Delgado b563bfb8d7 spi/xilinx: Remove remaining_words driver data variable
The variable never leaves the scope of txrx_bufs.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-01-28 19:42:43 +00:00
Ricardo Ribalda Delgado 99082eab63 spi/xilinx: Remove iowrite/ioread wrappers
Save a stack level and cleanup code.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-01-28 19:42:43 +00:00
Ricardo Ribalda Delgado 17aaaa8032 spi/xilinx: Convert bits_per_word in bytes_per_word
Simplify the code by using the unit used on most of the code logic.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-01-28 19:42:43 +00:00
Ricardo Ribalda Delgado d79b2d073a spi/xilinx: Convert remainding_bytes in remaining words
Simplify the code by using the unit used on most of the code logic.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-01-28 19:42:43 +00:00
Ricardo Ribalda Delgado c30929415a spi/xilinx: Make spi_tx and spi_rx simmetric
spi_rx handles the case where the buffer is null. Nevertheless spi_tx
did not handle it, and was handled by the caller function.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-01-28 19:42:43 +00:00
Ricardo Ribalda Delgado 24ba5e593f spi/xilinx: Remove rx_fn and tx_fn pointer
Simplify the code by removing the tx and and rx function pointers and
substitute them by a single function.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-01-28 19:42:42 +00:00
Ricardo Ribalda Delgado f9c6ef6cfe spi/xilinx: Support for spi mode CS_HIGH
The core controls the chip select lines individually.

By default, all the lines are consider active_low. After
spi_setup_transfer, it has its real value.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-01-28 19:42:42 +00:00
Ricardo Ribalda Delgado d9f5881242 spi/xilinx: Do not inhibit transmission in polling mode
When no irq is used, there is no need to inhibit the transmission for
every transaction. This inhibition was implemented to avoid a race
condition with the irq handler.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-01-28 19:42:42 +00:00
Ricardo Ribalda Delgado 5fe11cc09c spi/xilinx: Support cores with no interrupt
The core can run in polling mode. In fact, the performance of the core
is similar (or even better), due to the fact most of the spi
transactions are just a couple of bytes and there is one irq per
transactions.

When an mtd device is connected via spi, reading 8MB of data produces
more than 80K interrupts (with irq disabling, context swith....)

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-01-28 19:42:42 +00:00
Ricardo Ribalda Delgado 5b74d7a3b8 spi/xilinx: Use cached value of register
The control register has not changed since the previous access.
Therefore we can use the cached value and safe one bus access.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-01-28 19:42:42 +00:00
Ricardo Ribalda Delgado a87cbca0ac spi/xilinx: Code cleanup
On the transmission loop, check for remaining bytes at the loop
condition.

This way we can handle transmissions of 0 bytes and clean the code.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-01-28 19:42:42 +00:00
Ricardo Ribalda Delgado 899929baba spi/xilinx: Leave the IRQ always enabled.
Instead of enabling the IRQ and disabling it for every transaction.

Specially the small transactions (1,2 words) benefit from removing 3 bus
accesses.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-01-28 19:42:42 +00:00
Ricardo Ribalda Delgado 4c9a761402 spi/xilinx: Simplify spi_fill_tx_fifo
Instead of checking the TX_FULL flag for every transaction, find out the
size of the buffer at probe time and use it.

To avoid situations where the core had some data on the buffer before
initialization, the core is reseted before the buffer size is detected

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-01-28 19:42:42 +00:00
Ricardo Ribalda Delgado c5d348dffa spi/xilinx: Simplify data read from the Rx FIFO
The number of words in the read buffer will be exactly the same as the
number of words written on write buffer, once the transaction has
finished.

Instead of cheking the rx_empty flags for every word simply save the
number of words written by fill_tx_fifo.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-01-27 17:25:34 +00:00
Ricardo Ribalda Delgado 0240f94516 spi/xilinx: Support for spi mode LOOP
Hardware supports LOOP mode. Support it also in the driver.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-01-26 19:23:35 +00:00
Ricardo Ribalda Delgado bca690db90 spi/xilinx: Support for spi mode LSB_FIRST
Hardware supports LSB_FIRST mode. Support it also in the driver.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-01-26 19:23:35 +00:00
Michal Simek 9c0b8fd1a5 spi: xilinx: Remove .owner field for driver
There is no need to init .owner field.

Based on the patch from Peter Griffin <peter.griffin@linaro.org>
"mmc: remove .owner field for drivers using module_platform_driver"

This patch removes the superflous .owner field for drivers which
use the module_platform_driver API, as this is overriden in
platform_driver_register anyway."

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
2014-08-16 17:15:47 -05:00
Lars-Peter Clausen 4b153a2137 spi: xilinx: Use pdev->id instead of pdev->dev.id for the SPI bus number
The Xilinx SPI driver initializes the bus_num field of the SPI master to
pdev->dev.id. pdev->dev.id is always 0 for platform devices which causes bus
number conflicts for the SPI controller when creating multiple device instances
of the driver. Instead use pdev->id which will have the assignt platform device
id. If the device is instantiated via devicetree pdev->id is -1 which will cause
the SPI core to dynamically assign a id (or use the id defined via a alias in
the devicetree).

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>
2014-07-10 12:38:45 +02:00
Mark Brown 45b15d98a9 Merge remote-tracking branches 'spi/topic/xilinx' and 'spi/topic/xtfpga' into spi-next 2014-03-30 00:51:48 +00:00
Jingoo Han 6ff8672a96 spi: xilinx: remove unnecessary spaces
Remove unnecessary space in order to fix the following
checkpatch issues.

  WARNING: Unnecessary space after function pointer name

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Reviewed-by: Michal Simek <monstr@monstr.eu>
Signed-off-by: Mark Brown <broonie@linaro.org>
2014-02-27 13:40:07 +09:00
Axel Lin 9bf46f6df5 spi: xilinx: Convert to let spi core validate bits_per_word
Set bits_per_word_mask so spi core will reject transfers that attempt to use
an unsupported bits_per_word value.

spi_bitbang requires custom setup_transfer() to be defined if there is a
custom txrx_bufs(). Thus keep the empty xilinx_spi_setup_transfer() function
in the code.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
2014-02-23 12:53:21 +09:00
Paul Gortmaker 3a44623d5e spi: delete non-required instances of include <linux/init.h>
None of these files are actually using any __init type directives
and hence don't need to include <linux/init.h>.  Most are just a
left over from __devinit and __cpuinit removal, or simply due to
code getting copied from one driver to the next.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
2014-02-03 12:20:35 +00:00
Wolfram Sang 16735d022f tree-wide: use reinit_completion instead of INIT_COMPLETION
Use this new function to make code more comprehensible, since we are
reinitialzing the completion, not initializing.

[akpm@linux-foundation.org: linux-next resyncs]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org> (personally at LCE13)
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-15 09:32:21 +09:00
Axel Lin 94c69f765f spi: bitbang: Let spi_bitbang_start() take a reference to master
Many drivers that use bitbang library have a leak on probe error paths.
This is because once a spi_master_get() call succeeds, we need an additional
spi_master_put() call to free the memory.

Fix this issue by moving the code taking a reference to master to
spi_bitbang_start(), so spi_bitbang_start() will take a reference to master on
success. With this change, the caller is responsible for calling
spi_bitbang_stop() to decrement the reference and spi_master_put() as
counterpart of spi_alloc_master() to prevent a memory leak.

So now we have below patten for drivers using bitbang library:

probe:
spi_alloc_master        -> Init reference count to 1
spi_bitbang_start       -> Increment reference count
remove:
spi_bitbang_stop        -> Decrement reference count
spi_master_put          -> Decrement reference count (reference count reaches 0)

Fixup all users accordingly.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Suggested-by: Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
Acked-by: Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
Signed-off-by: Mark Brown <broonie@linaro.org>
2013-09-17 12:56:14 +01:00
Mark Brown 68aa4cb337 Merge remote-tracking branch 'spi/topic/pdata' into spi-next 2013-09-01 13:49:03 +01:00
Mark Brown b5f9a9d511 Merge remote-tracking branch 'spi/topic/rspi' into spi-pdata
Conflicts:
	drivers/spi/spi-rspi.c
2013-08-29 13:59:05 +01:00
Jingoo Han 8074cf063e spi: use dev_get_platdata()
Use the wrapper function for retrieving the platform data instead of
accessing dev->platform_data directly.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
2013-08-29 13:56:23 +01:00
Mark Brown 30af9b558a spi/bitbang: Drop empty setup() functions
Now that the bitbang core does not require a setup() function we can
drop the check in the altera, nuc900 and xilinx drivers.

Signed-off-by: Mark Brown <broonie@linaro.org>
2013-08-09 17:32:10 +01:00
Dan Carpenter 9ca1273bb9 spi/xilinx: signedness issue checking platform_get_irq()
In xilinx_spi_probe() we use xspi->irq to store negative error codes so
it has to be signed.  We weren't going to use the upper bit any way so
this is fine.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
2013-07-17 18:19:44 +01:00
Michal Simek 7b3b7432ae spi/xilinx: Simplify irq allocation
Use devm_request_irq() for irq allocation which
simplify driver code.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
2013-07-15 11:45:53 +01:00
Michal Simek be3acdff94 spi/xilinx: Use of_property_read_u32 for reading value from node
It simplifies driver probing.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
2013-07-15 11:45:53 +01:00
Michal Simek ad3fdbcaf9 spi/xilinx: Clean ioremap calling
devm_ioremap_resource() automatically checks that
struct resource is initialized.
Also group platform_get_resource() and devm_ioremap_resource()
together.
And remove mem resource from struct xilinx_spi.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
2013-07-15 11:45:53 +01:00
Michal Simek 5586c09e19 spi/xilinx: Remove CONFIG_OF from the driver
dev.of_node is in struct device all the time.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
2013-07-15 11:45:53 +01:00
Mark Brown 7cb2abd05f spi/xilinx: Refer to platform device as pdev in probe() and remove()
This is a more traditional name and makes things a bit clearer when
referring to actual struct devices as we do frequently during probe().

Signed-off-by: Mark Brown <broonie@linaro.org>
Acked-by: Michal Simek <michal.simek@xilinx.com>
2013-07-15 11:45:52 +01:00
Mark Brown d81c0bbbf8 spi/xilinx: Remove remains of of_platform device registration
In the past there used to be a separate platform device type for device
tree systems so the probe and removal functions were split into generic
and bus sections. Since this is no longer the case simplify the code (and
remove some unprototyped exports) by factoring everything into the bus
probe() and remove().

Signed-off-by: Mark Brown <broonie@linaro.org>
2013-07-15 11:45:52 +01:00
Mark Brown c40537d008 spi/xilinx: Convert to devm_ioremap_resource()
Saves code and reduces the possibility of error.

Signed-off-by: Mark Brown <broonie@linaro.org>
2013-07-15 11:45:52 +01:00
Michal Simek e076195390 spi/xilinx: Revert master->setup function removal
master->setup() must be initialized to be able
to successfully run spi_bitbang_start()
and satisfy if/else logic there.

"spi: convert drivers to use bits_per_word_mask"
(sha1: 24778be20f)

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
2013-07-10 09:45:48 +01:00
Mark Brown ed893559c9 Merge remote-tracking branch 'spi/topic/xilinx' into spi-next 2013-06-26 16:21:06 +01:00
Mark Brown 4581949d52 Merge remote-tracking branch 'spi/topic/bpw' into spi-next 2013-06-26 16:20:57 +01:00
dan.carpenter@oracle.com e33d085d11 spi: spi-xilinx: cleanup a check in xilinx_spi_txrx_bufs()
'!' has higher precedence than comparisons so the original condition
is equivalent to "if (xspi->remaining_bytes == 0)".  This makes the
static checkers complain.

xspi->remaining_bytes is signed and from looking at the code
briefly, I think it might be able to go negative.  I suspect that
going negative may cause a bug, but I don't have the hardware and
can't test.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
2013-06-10 10:28:04 +01:00
Sachin Kamat 913b19660e spi: spi-xilinx: Remove redundant platform_set_drvdata()
Setting platform data to NULL is not necessary.
Also fixes the following sparse warning:
drivers/spi/spi-xilinx.c:508:35: warning: Using plain integer as NULL pointer

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Mark Brown <broonie@linaro.org>
2013-06-04 18:38:32 +01:00
Michal Simek 082339bc63 spi: spi-xilinx: Add run run-time endian detection
Do not load endian value from platform data
and rather autodetect it.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
2013-06-04 18:37:35 +01:00
Peter Crosthwaite 68c315bb95 spi: spi-xilinx: Remove ISR race condition
The ISR currently consumes the rx buffer data and re-enables transmission
from within interrupt context. This is bad because if the interrupt
occurs again before the ISR exits, the new interrupt will be erroneously
cleared by the still completing ISR.

Simplified the ISR by just setting the completion variable and exiting with
no action. Then just looped the transmit functionality in
xilinx_spi_txrx_bufs().

Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
2013-06-04 18:32:19 +01:00