The device which is actually does DMA may have a limitation of the maximum
segment size. Respect this setting when preparing scatter-gather list.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

When a controller has only PIO support it is very likely that we will
run into use cases where we spend a very large amount of time consuming
CPU.  Code that does this should call cond_resched() every once in a
while to give other tasks more of a chance to run so do that in the main
SPI loop, the overhead is negligable if it's not needed.
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

In addition to providing direct access to SPI bus, some spi controller
hardwares (like ti-qspi) provide special port (like memory mapped port)
that are optimized to improve SPI flash read performance.
This means the controller can automatically send the SPI signals
required to read data from the SPI flash device.
For this, SPI controller needs to know flash specific information like
read command to use, dummy bytes and address width.

Introduce spi_flash_read() interface to support accelerated read
over SPI flash devices. SPI master drivers can implement this callback to
support interfaces such as memory mapped read etc. m25p80 flash driver
and other flash drivers can call this make use of such interfaces. The
interface should only be used with SPI flashes and cannot be used with
other SPI devices.
Signed-off-by: Vignesh R <vigneshr@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi->irq was ignoring GpioInt property setting it to -1.
acpi_dev_gpio_irq_get returns and configure the slave IRQ according to
the ACPI slave node description.

It is now inline with devicetree behavior.
Acked-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Use to_spi_device() instead of open-coding it.
Signed-off-by: Geliang Tang <geliangtang@163.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

Fix parent-device reference leak due to SPI-core taking an unnecessary
reference to the parent when allocating the master structure, a
reference that was never released.

Note that driver core takes its own reference to the parent when the
master device is registered.

Fixes: 49dce689 ("spi doesn't need class_device")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org

Mark (and unmark) device nodes with the POPULATE flag as appropriate.
This is required to avoid multi probing when enabling and populating SPI
buses in DT overlays.

Based on commit 4f001fd3 ("i2c: Mark instantiated device nodes
with OF_POPULATE").
Suggested-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>

Uninline spi_unregister_device() in preparation of adding more code to
it. Add kerneldoc documentation while we're at it.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>

When submitting an identical spi_message multiple times via spi_sync
the spi_message.frame_length does not get reset to 0 in __spi_validate
before adding up all spi_transfer.len resulting in
frame_length > actual_length on all but the first spi_sync call.
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

Commit ca5d2485 ("spi: Add THIS_MODULE to spi_driver in SPI core")
adds the new __spi_register_driver() function, but keeps the kerneldoc
for the spi_register_driver() function in place and forgets to add the
description for the new owner parameter.
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

Add spi_register_driver helper macro that adds THIS_MODULE to
spi_driver for the registering driver. We rename and modify
the existing spi_register_driver to enable this.
Signed-off-by: Andrew F. Davis <afd@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

SPI controllers may need to be properly setup before chip selects
can be used. Therefore, wait until the spi controller has a chance
to perform their setup procedure before trying to use the chip
select.

This also insures that the chip selects pins are in a good
state before asseting them which otherwise may cause confusion.
Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
Tested-by: Grygorii Strashko <grygorii.strashko@ti.com>
Tested-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

When building docs with make htmldocs, warnings about not having
a description for the return value are reported, i.e:

warning: No description found for return value of 'spi_register_driver'

Fix these by following the kernel-doc conventions explained in
Documentation/kernel-doc-nano-HOWTO.txt.
Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

Check if GPIO pin is valid by API helper function.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

Propagate the actual return code of __spi_validate_bits_per_word() in
spi_setup().
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

Currently the IRQs for SPI client devices, registered via device-tree,
are mapped when the client devices are registered. If the corresponding
irq-chip has not been probed yet, then the probing of the client device
will fail and will not be retried. Resolve this by mapping the IRQ at
probe time and allow the probe to be deferred if the IRQ is not yet
available.

If of_irq_get() returns an error that is not -EPROBE_DEFER, then assume
that the SPI client does not have an IRQ and set the IRQ number to zero
(which is equivalent to irq_of_parse_and_map()).

This is based on some inputs from Thierry Reding <treding@nvidia.com>.

Cc: Thierry Reding <treding@nvidia.com>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

report transfer sizes as a histogram via the following files:
  /sys/class/spi_master/spi*/statistics/transfer_bytes_histo_*
  /sys/class/spi_master/spi*/spi*.*/statistics/transfer_bytes_histo_*
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

Actually, spi_master_put() after spi_alloc_master() must _not_ be followed
by kfree(). The memory is already freed with the call to spi_master_put()
through spi_master_class, which registers a release function. Calling both
spi_master_put() and kfree() results in often nasty (and delayed) crashes
elsewhere in the kernel, often in the networking stack.

This reverts commit eb4af0f5.

Link to patch and concerns: https://lkml.org/lkml/2012/9/3/269
or
http://lkml.iu.edu/hypermail/linux/kernel/1209.0/00790.html

Alexey Klimov: This revert becomes valid after
94c69f76 when spi-imx.c
has been fixed and there is no need to call kfree() so comment
for spi_alloc_master() should be fixed.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Alexey Klimov <alexey.klimov@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org

This allows drivers for devices connected via SPI to check if the
controller supports a given bits_per_word value during setup.
Currently any BPW value is accepted durings setup, and transfers
are rejected later.
Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

If a slave appears with no maximum transfer speed specified fall back to
using the maximum for the master instead.  It's questionable if we
should let slaves do this but let's be defensive.
Signed-off-by: Mark Brown <broonie@kernel.org>

For spi without dma channel and use can_dma(), it can
use master->dev for struct device.
Signed-off-by: Leilk Liu <leilk.liu@mediatek.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

per spi-master statistics accessible as:
  /sys/class/spi_master/spi*/statistics/*

per spi-device statistics accessible via:
  /sys/class/spi_master/spi*/spi*.*/statistics/*

The following statistics are exposed as separate "files" inside
these directories:
* messages              number of spi_messages
* transfers             number of spi_transfers
* bytes                 number of bytes transferred
* bytes_rx              number of bytes transmitted
* bytes_tx              number of bytes received
* errors                number of errors encounterd
* timedout              number of messages that have timed out
* spi_async             number of spi_messages submitted using spi_async
* spi_sync              number of spi_messages submitted using spi_sync
* spi_sync_immediate    number of spi_messages submitted using spi_sync,
                        that are handled immediately without a context switch
                        to the spi_pump worker-thread
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi_map_buf() processes mapping of vmalloc-ed buffers in a special way,
making mapping of every page separately. However, if the buffer is not
aligned to page boundary (e.g. sub-array in a vmalloc-ed array), it
fills the scatter table with page-size unaligned pieces, that cross
page boundaries. This is incorrect and can, for example, cause memory
corruption and various crashes when working with ubifs on spi-nor chips
(though those drivers are themselves buggy in that they should be
providing DMAable memory to the SPI framework).

Fix this by using proper scatter table size and intra-page buffer lengths,
so that the whole buffer splits into separate scatter table entries on
page boundaries.
Signed-off-by: Andrew Gabbasov <andrew_gabbasov@mentor.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

The case where spi_master sets the flags SPI_MASTER_MUST_RX/TX while
CONFIG_HAS_DMA is unset (which is unlikley) together with a driver
that reuses spi_messages with rx/tx_buff set to NULL, can result in:
* data disclosure over the SPI (for tx_buf == NULL)
* memory corruption (for rx_buf == NULL)

This happenes when dummy_rx/dummy_tx are changing address due to krealloc
or free and an allocation of the memory by a different part of the kernel.
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

Fix a race (with some kernel configurations) where a queued
master->pump_messages runs and frees dummy_tx/rx before
spi_unmap_msg is running (or is finished).

This results in the following messages:
  BUG: Bad page state in process
  page:db7ba030 count:0 mapcount:0 mapping:  (null) index:0x0
  flags: 0x200(arch_1)
  page dumped because: PAGE_FLAGS_CHECK_AT_PREP flag set
  ...
Reported-by: Noralf Trønnes <noralf@tronnes.org>
Suggested-by: Noralf Trønnes <noralf@tronnes.org>
Tested-by: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org

Some spi device drivers use the same tx_buf and rx_buf repeatly for better
performance such as driver/input/touchsreen/ads7846.c, but spi core grab tx_buf
/rx_buf of transfer and set them as dummy_tx/dummy_rx once they are NULL. Thus,
in the second time the tx_buf/rx_buf will be replaced by dummy_tx/dummy_rx and
the data which produced by the last tx or rx may be wrongly sent to the device
or handled by the upper level protocol. This patch just keep the orignal value
of tx_buf/rx_buf if they are NULL after this transfer processed.
Signed-off-by: Robin Gong <b38343@freescale.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

If a driver doesn't implement the master->handle_err() callback and an
SPI transfer fails, the kernel will crash with a NULL pointer
dereference:

    Unable to handle kernel NULL pointer dereference at virtual address 00000000
    pgd = c0003000
    [00000000] *pgd=80000040004003, *pmd=00000000
    Internal error: Oops: 80000206 [#1] SMP ARM
    Modules linked in:
    CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.0.0-rc7-koelsch-05861-g1fc9fdd4add4f783 #1046
    Hardware name: Generic R8A7791 (Flattened Device Tree)
    task: eec359c0 ti: eec54000 task.ti: eec54000
    PC is at 0x0
    LR is at spi_transfer_one_message+0x1cc/0x1f0

Make the master->handle_err() callback optional to avoid the crash.

Also fix a spelling mistake in the callback documentation while we're at
it.

Fixes: b716c4ff ("spi: introduce master->handle_err() callback")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>

Trying to register an SPI device asynchronously (via async_schedule() call)
results in an ugly complaint from request_module() warning about potential
deadlock (because request_module tries to wait for async works to
complete, the caller is also an async work in this case).

While we could try to switch to using request_module_nowait(), other buses,
as well as SPI itself when not using device tree, do not try to load
modules explicitly, but rather rely on the standard infrastructure (such as
udev) to execute module loading. There is no reason why SPI OF-described
devices should be treated differently.
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

With spidev the mesg->complete callback points to spidev_complete.
Calling this unblocks spidev_sync and so spidev_sync_write finishes. As
the struct spi_message just read is a local variable in
spidev_sync_write and recording the trace event accesses this message
the recording is better done first. The same can happen for
spidev_sync_read.

This fixes an oops observed on a 3.14-rt system with spidev activity
after

	echo 1 > /sys/kernel/debug/tracing/events/spi/enable

.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org

Some devices samples state of the chip select signal during power up
and act differently based on this state, so SPI core should ensure
that CS line is driven in non-active state after spi_setup().
Signed-off-by: Ivan T. Ivanov <iivanov@mm-sol.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

All SPI drivers have been converted from legacy suspend/resume callbacks to
dev_pm_ops. So we can finally remove support for legacy PM from the SPI
core.

Since there aren't any special bus specific things to do during
suspend/resume and since the PM core will automatically fallback directly to
using the device's PM ops if no bus PM ops are specified there is no need to
have any special SPI bus PM ops.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

This callback would be useful to handle an error that occurs in the generic
implementation of transfer_one_message(). The good candidate for this is to
drain FIFO and / or to terminate DMA transfers when timeout happened.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

return type of wait_for_completion_timeout is unsigned long not int, this
patch changes the type of m from int to unsigned long.
Signed-off-by: Nicholas Mc Guire <der.herr@hofr.at>
Signed-off-by: Mark Brown <broonie@kernel.org>

Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

In order to avoid the situation where the kthread is waiting for another
context to make the hardware idle let the message pump know if it's being
called from the worker thread context and if it isn't then defer to the
worker thread instead of idling the hardware immediately. This will ensure
that if this situation happens we block rather than busy waiting.
Signed-off-by: Mark Brown <broonie@kernel.org>

If we are using the standard SPI message pump (which all drivers should be
transitioning over to) then special case the message enqueue and instead of
starting the worker thread to push messages to the hardware do so in the
context of the caller if the controller is idle. This avoids a context
switch in the common case where the controller has a single user in a
single thread, for short PIO transfers there may be no need to context
switch away from the calling context to complete the transfer.

The code is a bit more complex than is desirable in part due to the need
to handle drivers not using the standard queue and in part due to handling
the various combinations of bus locking and asynchronous submission in
interrupt context.

It is still suboptimal since it will still wake the message pump for each
transfer in order to schedule idling of the hardware and if multiple
contexts are using the controller simultaneously a caller may end up
pumping a message for some random other thread rather than for itself,
and if the thread ends up deferring due to another context idling the
hardware then it will just busy wait.  It can, however, have the benefit
of aggregating power up and down of the hardware when a caller performs
a series of transfers back to back without any need for the use of
spi_async().
Signed-off-by: Mark Brown <broonie@kernel.org>

cur_msg is updated under the queue lock and holds the message we are
currently processing. Since currently we only ever do removals in the
pump kthread it doesn't matter in what order we do things but we want
to be able to push things out from the submitting thread so pull the
check to see if we're currently handling a message before we check to
see if the queue is idle.
Signed-off-by: Mark Brown <broonie@kernel.org>

Since most devices now do use the standard queue and in order to avoid
initialisation ordering issues being introduced by further refactorings
to improve performance move the initialisation of the queue and the lock
for it to the main master allocation.
Signed-off-by: Mark Brown <broonie@kernel.org>

kthread_run() could return ERR_PTR(-EINTR) from kthread_create_on_node().
Return the actual error code in spi_init_queue() instead of mangling it to
-ENOMEM.
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

Since commit ce79d54a ("spi/of: Add OF notifier handler") the
following warning is seen on a imx53 system that has CONFIG_OF_DYNAMIC=n:

[    0.048119] ------------[ cut here ]------------
[    0.048146] WARNING: CPU: 0 PID: 1 at drivers/spi/spi.c:2419 spi_init+0x60/0xa8()
[    0.048158] Modules linked in:
[    0.048183] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.18.0-rc6-next-20141126-00003-g9388e85 #2080
[    0.048193] Hardware name: Freescale i.MX53 (Device Tree Support)
[    0.048203] Backtrace:
[    0.048235] [<80011f74>] (dump_backtrace) from [<80012110>] (show_stack+0x18/0x1c)
[    0.048246]  r6:00000973 r5:00000000 r4:00000000 r3:00000000
[    0.048284] [<800120f8>] (show_stack) from [<806b3ad8>] (dump_stack+0x88/0xa4)
[    0.048312] [<806b3a50>] (dump_stack) from [<8002a55c>] (warn_slowpath_common+0x80/0xbc)
[    0.048320]  r5:8096cfcc r4:00000000
[    0.048343] [<8002a4dc>] (warn_slowpath_common) from [<8002a5bc>] (warn_slowpath_null+0x24/0x2c)
[    0.048354]  r8:8096cf6c r7:809355ec r6:ddcd7c00 r5:812029e4 r4:00000000
[    0.048389] [<8002a598>] (warn_slowpath_null) from [<8096cfcc>] (spi_init+0x60/0xa8)
[    0.048405] [<8096cf6c>] (spi_init) from [<80008a7c>] (do_one_initcall+0x88/0x1e0)
[    0.048415]  r5:8099e018 r4:8099e018
[    0.048438] [<800089f4>] (do_one_initcall) from [<80935e38>] (kernel_init_freeable+0x110/0x1e0)
[    0.048448]  r10:80980700 r9:809806e4 r8:000000cc r7:809355ec r6:809f8940 r5:00000002
[    0.048478]  r4:8098d744
[    0.048508] [<80935d28>] (kernel_init_freeable) from [<806ae574>] (kernel_init+0x10/0xf4)
[    0.048517]  r10:00000000 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:806ae564
[    0.048547]  r4:00000000
[    0.048565] [<806ae564>] (kernel_init) from [<8000ed68>] (ret_from_fork+0x14/0x2c)
[    0.048574]  r4:00000000 r3:00000000
[    0.048616] ---[ end trace 405a65d177dae4fd ]---

Only check of_reconfig_notifier_register() in the CONFIG_OF_DYNAMIC=y case,
as intended by commit ce79d54a.
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Grant Likely <grant.likely@linaro.org>