Some SPI masters require slave selection before the transfer
can begin [1]. The SPI framework currently selects the chip using
either 1) the internal CS mechanism or 2) the GPIO CS, but not both.

This patch adds a new master->flags define to indicate both the GPIO
CS and the internal chip select mechanism should be used.

Tested On:
    Altera CycloneV development kit
    Compile tested for build errors on x86_64 (allyesconfigs)

[1] DesignWare dw_apb_ssi Databook, Version 3.20a (page 39)
Signed-off-by: NThor Thayer <tthayer@opensource.altera.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

When reading SPI flash as MTD device, the transfer length is
directly passed to the spi driver. If the requested data size
exceeds 512KB, it will cause the time out calculation to
overflow since transfer length is 32-bit unsigned integer.
This issue is resolved by using 64-bit unsigned integer
to perform the arithmetic.
Signed-off-by: NSien Wu <sien.wu@ni.com>
Acked-by: NBrad Keryan <brad.keryan@ni.com>
Acked-by: NGratian Crisan <gratian.crisan@ni.com>
Acked-by: NBrad Mouring <brad.mouring@ni.com>

Natinst-ReviewBoard-ID 150232
Signed-off-by: NMark Brown <broonie@kernel.org>

JFFS2 FS might sometime provide kmap'd buffers as destination
buffers to read data from flash. Update spi_map_buf() function to
generate sg_list for such buffers, so that SPI controllers drivers can
use DMA to read data into such buffers.
Signed-off-by: NVignesh R <vigneshr@ti.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

A couple of error paths were missing drops of io_mutex.
Reported-by: NJulia Lawall <julia.lawall@lip6.fr>
Signed-off-by: NMark Brown <broonie@kernel.org>

The current SPI code attempts to use bus_lock_mutex for two purposes. One
is to implement spi_bus_lock() which grants exclusive access to the bus.
The other is to serialize access to the physical hardware. This duplicate
purpose causes confusion which leads to cases where access is not locked
when a caller holds the bus lock mutex. Fix this by splitting out the I/O
functionality into a new io_mutex.

This means taking both mutexes in the DMA path, replacing the existing
mutex with the new I/O one in the message pump (the mutex now always
being taken in the message pump) and taking the bus lock mutex in
spi_sync(), allowing __spi_sync() to have no mutex handling.

While we're at it hoist the mutex further up the message pump before we
power up the device so that all power up/down of the block is covered by
it and there are no races with in-line pumping of messages.
Reported-by: NRich Felker <dalias@libc.org>
Tested-by: NRich Felker <dalias@libc.org>
Signed-off-by: NMark Brown <broonie@kernel.org>

This patch adds supports for SPI device enumeration and removal via
ACPI reconfiguration notifications that are send as a result of an
ACPI table load or unload operation.

The code is very similar with the device tree reconfiguration code
with only small differences in the way we test and set the enumerated
state of the device:

 * the equivalent of device tree's OF_POPULATED flag is the
   flags.visited field in the ACPI device and the following wrappers
   are used to manipulate it: acpi_device_enumerated(),
   acpi_device_set_enumerated() and acpi_device_clear_enumerated()

 * the device tree code checks of status of the OF_POPULATED flag to
   avoid trying to create duplicate Linux devices in two places: once
   when the controller is probed, and once when the reconfigure event
   is received; in the ACPI code the check is performed only once when
   the ACPI namespace is searched because this code path is invoked in
   both of the two mentioned cases

The rest of the enumeration handling is similar with device tree: when
the Linux device is unregistered the ACPI device is marked as not
enumerated; also, when a device remove notification is received we
check that the device is in the enumerated state before continuing
with the removal of the Linux device.
Signed-off-by: NOctavian Purdila <octavian.purdila@intel.com>
Reviewed-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: NMark Brown <broonie@kernel.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Few SPI devices provide accelerated read interfaces to read from
SPI-NOR flash devices. These hardwares also support DMA to transfer data
from flash to memory either via mem-to-mem DMA or dedicated slave DMA
channels. Hence, add support for DMA in order to improve throughput and
reduce CPU load.
Use spi_map_buf() to get sg table for the buffer and pass it to SPI
driver.
Signed-off-by: NVignesh R <vigneshr@ti.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

This fixes a simple typo in one of the comments.
Signed-off-by: NMoritz Fischer <moritz.fischer@ettus.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

Current spi_map_buf() implementation supports creates sg_table for
vmalloc'd and kmalloc'd buffers. Therefore return error if kmap'd buffer
(or any other buffer) is passed to spi_map_buf().
Signed-off-by: NVignesh R <vigneshr@ti.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

Let all SPI masters ignore their children: when it comes
to power management: SPI children have no business doing
keeping their parents awake: they are completely autonomous
devices that just use their parent to talk, and the latter
usecase must be power managed by the host itself on a
per-message basis.
Reviewed-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NMark Brown <broonie@kernel.org>

External users may use spi_bus_lock to get exclusive access. This will
also grab the bus_lock_mutex and may therefore result in a deadlock if
__spi_pump_messages also tries to get the mutex.

Therefore adapt spi_pump_messages as well as spi_sync to preset the
bus_locked parameter according to the master->bus_lock_flag.

Fixes: 49023d2e ("spi: core: Fix deadlock when sending messages")
Signed-off-by: NHeiko Stuebner <heiko@sntech.de>
Signed-off-by: NMark Brown <broonie@kernel.org>

The spi_split_transfers_maxsize() gfp parameter is missing in the
function kernel-doc so building gives the following warning:

.//drivers/spi/spi.c:2359: warning: No description found for parameter 'gfp'
Signed-off-by: NJavier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

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: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

The function __spi_pump_messages() is called by spi_pump_messages() and
__spi_sync(). The function __spi_sync() has an argument 'bus_locked'
that indicates if it is called with the SPI bus mutex held or not. If
'bus_locked' is false then __spi_sync() will acquire the mutex itself.

Commit 556351f1 ("spi: introduce accelerated read support for spi
flash devices") made a change to acquire the SPI bus mutex within
__spi_pump_messages(). However, this change did not check to see if the
mutex is already held. If __spi_sync() is called with the mutex held
(ie. 'bus_locked' is true), then a deadlock occurs when
__spi_pump_messages() is called.

Fix this deadlock by passing the 'bus_locked' state from __spi_sync() to
__spi_pump_messages() and only acquire the mutex if not already held. In
the case where __spi_pump_messages() is called from spi_pump_messages()
it is assumed that the mutex is not held and so call
__spi_pump_messages() with 'bus_locked' set to false. Finally, move the
unlocking of the mutex to the end of the __spi_pump_messages() function
to simplify the code and only call cond_resched() if there are no
errors.

Fixes: 556351f1 ("spi: introduce accelerated read support for spi flash devices")
Signed-off-by: NJon Hunter <jonathanh@nvidia.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

This patch fix following warnings while make xmldocs.

.//drivers/spi/spi.c:2354: warning: Excess function parameter
'message' description in 'spi_split_transfers_maxsize'
.//drivers/spi/spi.c:2354: warning: Excess function parameter
 'max_size' description in 'spi_split_transfers_maxsize'
Signed-off-by: NMasanari Iida <standby24x7@gmail.com>
Signed-off-by: NMark 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: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NMark Brown <broonie@kernel.org>

Add missing docbook documentation for the gfp parameter
in function spi_replace_transfers.
Signed-off-by: NMartin Sperl <kernel@martin.sperl.org>
Signed-off-by: NMark Brown <broonie@kernel.org>

Use min_t(size_t,..) in order to avoid the following
build warning on ARM64:

include/linux/kernel.h:754:17: warning: comparison of distinct pointer types lacks a cast
  (void) (&_min1 == &_min2);  \
                 ^
drivers/spi/spi.c:2304:17: note: in expansion of macro 'min'
  xfers[0].len = min(maxsize, xfer[0].len);
Suggested-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NFabio Estevam <fabio.estevam@nxp.com>
Acked-by: NMartin Sperl <kernel@martin.sperl.org>
Signed-off-by: NMark Brown <broonie@kernel.org>

Use %zu for printing 'size_t' type in order to fix the following
build warning on ARM64:

drivers/spi/spi.c: In function '__spi_split_transfer_maxsize':
drivers/spi/spi.c:2278:2: warning: format '%i' expects argument of type 'int', but argument 4 has type 'size_t' [-Wformat=]
Signed-off-by: NFabio Estevam <fabio.estevam@nxp.com>
Acked-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Acked-by: NMartin Sperl <kernel@martin.sperl.org>
Signed-off-by: NMark Brown <broonie@kernel.org>

__spi_split_transfer_maxsize() can be made static as it is only
used in this file.

This fixes the following sparse warning:

drivers/spi/spi.c:2266:5: warning: symbol '__spi_split_transfer_maxsize' was not declared. Should it be static?
Signed-off-by: NFabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

spi_replace_transfers() returns error pointers on error, it never
returns NULL.

Fixes: d9f12122 ('spi: core: add spi_split_transfers_maxsize')
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NMark 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: NVignesh R <vigneshr@ti.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

Add spi_split_transfers_maxsize method that splits
spi_transfers transparently into multiple transfers
that are below the given max-size.

This makes use of the spi_res framework via
spi_replace_transfers to allocate/free the extra
transfers as well as reverting back the changes applied
while processing the spi_message.
Signed-off-by: NMartin Sperl <kernel@martin.sperl.org>
Signed-off-by: NMark Brown <broonie@kernel.org>

Add the spi_replace_transfers method that can get used
to replace some spi_transfers from a spi_message with other
transfers.
Signed-off-by: NMartin Sperl <kernel@martin.sperl.org>
Signed-off-by: NMark Brown <broonie@kernel.org>

SPI resource management framework used while processing a spi_message
via the spi-core.

The basic idea is taken from devres, but as the allocation may happen
fairly frequently, some provisioning (in the form of an unused spi_device
pointer argument to spi_res_alloc) has been made so that at a later stage
we may implement reuse objects allocated earlier avoiding the repeated
allocation by keeping a cache of objects that we can reuse.

This framework can get used for:
* rewriting spi_messages
  * to fullfill alignment requirements of the spi_master HW
  * to fullfill transfer length requirements
    (e.g: transfers need to be less than 64k)
  * consolidate spi_messages with multiple transfers into a single transfer
  when the total transfer length is below a threshold.
* reimplement spi_unmap_buf without explicitly needing to check if it has
  been mapped
Signed-off-by: NMartin Sperl <kernel@martin.sperl.org>
Signed-off-by: NMark Brown <broonie@kernel.org>

In Windows it is up to the SPI host controller driver to handle the ACPI
DeviceSelection as it likes. The SPI core does not take any part in it.
This is different in Linux because we always expect to have chip select in
range of 0 .. master->num_chipselect - 1.

In order to support this in Linux we need a way to allow the driver to
translate between ACPI DeviceSelection field and Linux chip select number
so provide a new optional hook ->fw_translate_cs() that can be used by a
driver to handle translation and call this hook if set during SPI slave
ACPI enumeration.
Signed-off-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: NJarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: NMark 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: NMark Brown <broonie@kernel.org>
Signed-off-by: NChristophe Ricard <christophe-h.ricard@st.com>
Acked-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Use to_spi_device() instead of open-coding it.
Signed-off-by: NGeliang Tang <geliangtang@163.com>
Signed-off-by: NMark 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: NJohan Hovold <johan@kernel.org>
Signed-off-by: NMark 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: NMark Brown <broonie@kernel.org>
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NMark 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: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NMark 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: NMartin Sperl <kernel@martin.sperl.org>
Signed-off-by: NMark 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: NThierry Reding <treding@nvidia.com>
Signed-off-by: NMark 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: NAndrew F. Davis <afd@ti.com>
Signed-off-by: NMark 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: NFranklin S Cooper Jr <fcooper@ti.com>
Tested-by: NGrygorii Strashko <grygorii.strashko@ti.com>
Tested-by: NIvan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: NMark 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: NJavier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

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

Propagate the actual return code of __spi_validate_bits_per_word() in
spi_setup().
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NMark 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: NJon Hunter <jonathanh@nvidia.com>
Signed-off-by: NMark 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: NMartin Sperl <kernel@martin.sperl.org>
Signed-off-by: NMark Brown <broonie@kernel.org>