Some controllers like qcom geni need the parent device to be used for
dma mapping, so add a dma_map_dev field and let drivers fill this to be
used as mapping device
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Link: https://lore.kernel.org/r/20210625052213.32260-4-vkoul@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
There is an assignment of ancillary->mode to itself which looks
dubious since the proceeding comment states that the speed and
mode is taken over from the SPI main device, indicating that
ancillary->mode should assigned using the value spi->mode.
Fix this.
Addresses-Coverity: ("Self assignment")
Fixes: 0c79378c01 ("spi: add ancillary device support")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20210623172300.161484-1-colin.king@canonical.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Introduce support for ancillary devices, similar to existing
implementation for I2C. This is useful for devices having
multiple chip-selects, for example some microcontrollers
provide a normal SPI interface and a flashing SPI interface.
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Link: https://lore.kernel.org/r/20210621175359.126729-2-sebastian.reichel@collabora.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Add OF support as already done for ACPI to take driver
MODULE_DEVICE_TABLE(of, ..) into account.
For example with this change a spi nor device MODALIAS changes from:
MODALIAS=spi:spi-nor
to
MODALIAS=of:Nspi-flashT(null)Cjedec,spi-nor
Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
Link: https://lore.kernel.org/r/20210525091003.18228-1-m.felsch@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>
No one seems to be using this global and exported function, so remove it
as it is no longer needed.
Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20210609071918.2852069-1-gregkh@linuxfoundation.org
Signed-off-by: Mark Brown <broonie@kernel.org>
It is helpful to see what state of CS signal was during one
or another SPI operation. All the same for SPI setup.
Enable tracing of the SPI setup and CS selection.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Message-Id: <20210526195655.75691-1-andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
When a spi device is unregistered and triggers a driver unbind, the
driver might need to access the spi device. So, don't have the
controller clean up the spi device before the driver is unbound. Clean
up the spi device after the driver is unbound.
Fixes: c7299fea67 ("spi: Fix spi device unregister flow")
Reported-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Tested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20210505164734.175546-1-saravanak@google.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Currently GPIO CS handling, when descriptors are in use, doesn't
take into consideration that in ACPI case the default polarity
is Active High and can't be altered. Instead we have to use the
per-chip definition provided by SPISerialBus() resource.
Fixes: 766c6b63aa ("spi: fix client driver breakages when using GPIO descriptors")
Cc: Liguang Zhang <zhangliguang@linux.alibaba.com>
Cc: Jay Fang <f.fangjian@huawei.com>
Cc: Sven Van Asbroeck <thesven73@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Xin Hao <xhao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20210511140912.30757-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
We have a lot of hard coded values in nanoseconds or other units.
Use predefined constants to make it more clear.
While at it, add or amend comments in the corresponding functions.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210510131120.49253-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
this patch takes the io_mutex to prevent an unprotected HW
register modification in the set_cs_timing callback.
Fixes: 4cea6b8cc3 ("spi: add power control when set_cs_timing")
Signed-off-by: Leilk Liu <leilk.liu@mediatek.com>
Link: https://lore.kernel.org/r/20210508060214.1485-1-leilk.liu@mediatek.com
Signed-off-by: Mark Brown <broonie@kernel.org>
When an SPI device is unregistered, the spi->controller->cleanup() is
called in the device's release callback. That's wrong for a couple of
reasons:
1. spi_dev_put() can be called before spi_add_device() is called. And
it's spi_add_device() that calls spi_setup(). This will cause clean()
to get called without the spi device ever being setup.
2. There's no guarantee that the controller's driver would be present by
the time the spi device's release function gets called.
3. It also causes "sleeping in atomic context" stack dump[1] when device
link deletion code does a put_device() on the spi device.
Fix these issues by simply moving the cleanup from the device release
callback to the actual spi_unregister_device() function.
[1] - https://lore.kernel.org/lkml/CAHp75Vc=FCGcUyS0v6fnxme2YJ+qD+Y-hQDQLa2JhWNON9VmsQ@mail.gmail.com/
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20210426235638.1285530-1-saravanak@google.com
Signed-off-by: Mark Brown <broonie@kernel.org>
The enable1 is confusing name. Change it to clearly show what is
the intention behind it. No functional changes.
Fixes: 25093bdeb6 ("spi: implement SW control for CS times")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210420131846.75983-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Each time we call spi_get_gpio_descs() the num_chipselect is overwritten
either by new value or by the old one. This is an extra operation in case
gpiod_count() returns an error. Besides that it slashes the error handling
of gpiod_count().
Refactor the code to make error handling of gpiod_count() call cleaner.
Note, that gpiod_count() never returns 0, take this into account as well.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210420164040.40055-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
ffz(), that has been used to count unused native CSs,
might cause undefined behaviour when called against ~0U.
To fix that, open code it with ffs(~value) - 1.
Fixes: 7d93aecdb5 ("spi: Add generic support for unused native cs with cs-gpios")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210420164425.40287-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
The commit 7d93aecdb5 ("spi: Add generic support for unused native cs
with cs-gpios") excludes the valid case for the controllers that doesn't
need to switch native CS in order to perform the transfer, i.e. when
0 native
... ...
<n> - 1 native
<n> GPIO
<n> + 1 GPIO
... ...
where <n> defines maximum of native CSs supported by the controller.
To allow this, bail out from spi_get_gpio_descs() conditionally for
the controllers which explicitly marked with SPI_MASTER_GPIO_SS.
Fixes: 7d93aecdb5 ("spi: Add generic support for unused native cs with cs-gpios")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210420164425.40287-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Currently, the SPI core doesn't set the struct device fwnode pointer
when it creates a new SPI device. This means when the device is
registered the fwnode is NULL and the check in device_add which sets
the fwnode->dev pointer is skipped. This wasn't previously an issue,
however these two patches:
commit 4731210c09 ("gpiolib: Bind gpio_device to a driver to enable
fw_devlink=on by default")
commit ced2af4195 ("gpiolib: Don't probe gpio_device if it's not the
primary device")
Added some code to the GPIO core which relies on using that
fwnode->dev pointer to determine if a driver is bound to the fwnode
and if not bind a stub GPIO driver. This means the GPIO providers
behind SPI will get both the expected driver and this stub driver
causing the stub driver to fail if it attempts to request any pin
configuration. For example on my system:
madera-pinctrl madera-pinctrl: pin gpio5 already requested by madera-pinctrl; cannot claim for gpiochip3
madera-pinctrl madera-pinctrl: pin-4 (gpiochip3) status -22
madera-pinctrl madera-pinctrl: could not request pin 4 (gpio5) from group aif1 on device madera-pinctrl
gpio_stub_drv gpiochip3: Error applying setting, reverse things back
gpio_stub_drv: probe of gpiochip3 failed with error -22
The firmware node on the device created by the GPIO framework is set
through the of_node pointer hence things generally actually work,
however that fwnode->dev is never set, as the check was skipped at
device_add time. This fix appears to match how the I2C subsystem
handles the same situation.
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20210421101402.8468-1-ckeepax@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>
If the setup callback failed, but the controller has auto_runtime_pm
and set_cs, the setup failure could be missed.
Signed-off-by: Joe Burmeister <joe.burmeister@devtank.co.uk>
Link: https://lore.kernel.org/r/20210419130631.4586-1-joe.burmeister@devtank.co.uk
Signed-off-by: Mark Brown <broonie@kernel.org>
When initially probing the SPI slave device, the call for disabling an
SPI device without the SPI_CS_HIGH flag is not applied, as the
condition for checking whether or not the state to be applied equals the
one currently set evaluates to true.
This however might not necessarily be the case, as the chipselect might
be active.
Add a force flag to spi_set_cs which allows to override this
early exit condition. Set it to false everywhere except when called
from spi_setup to sync up the initial CS state.
Fixes commit d40f0b6f2e ("spi: Avoid setting the chip select if we don't
need to")
Signed-off-by: David Bauer <mail@david-bauer.net>
Link: https://lore.kernel.org/r/20210416195956.121811-1-mail@david-bauer.net
Signed-off-by: Mark Brown <broonie@kernel.org>
Use devm_add_action_or_reset() instead of devres_alloc() and
devres_add(), which works the same. This will simplify the
code. There is no functional changes.
Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Link: https://lore.kernel.org/r/1617843307-53853-1-git-send-email-tiantao6@hisilicon.com
Signed-off-by: Mark Brown <broonie@kernel.org>
We can't rely on the contents of the devres list during
spi_unregister_controller(), as the list is already torn down at the
time we perform devres_find() for devm_spi_release_controller. This
causes devices registered with devm_spi_alloc_{master,slave}() to be
mistakenly identified as legacy, non-devm managed devices and have their
reference counters decremented below 0.
------------[ cut here ]------------
WARNING: CPU: 1 PID: 660 at lib/refcount.c:28 refcount_warn_saturate+0x108/0x174
[<b0396f04>] (refcount_warn_saturate) from [<b03c56a4>] (kobject_put+0x90/0x98)
[<b03c5614>] (kobject_put) from [<b0447b4c>] (put_device+0x20/0x24)
r4:b6700140
[<b0447b2c>] (put_device) from [<b07515e8>] (devm_spi_release_controller+0x3c/0x40)
[<b07515ac>] (devm_spi_release_controller) from [<b045343c>] (release_nodes+0x84/0xc4)
r5:b6700180 r4:b6700100
[<b04533b8>] (release_nodes) from [<b0454160>] (devres_release_all+0x5c/0x60)
r8:b1638c54 r7:b117ad94 r6:b1638c10 r5:b117ad94 r4:b163dc10
[<b0454104>] (devres_release_all) from [<b044e41c>] (__device_release_driver+0x144/0x1ec)
r5:b117ad94 r4:b163dc10
[<b044e2d8>] (__device_release_driver) from [<b044f70c>] (device_driver_detach+0x84/0xa0)
r9:00000000 r8:00000000 r7:b117ad94 r6:b163dc54 r5:b1638c10 r4:b163dc10
[<b044f688>] (device_driver_detach) from [<b044d274>] (unbind_store+0xe4/0xf8)
Instead, determine the devm allocation state as a flag on the
controller which is guaranteed to be stable during cleanup.
Fixes: 5e844cc37a ("spi: Introduce device-managed SPI controller allocation")
Signed-off-by: William A. Kennington III <wak@google.com>
Link: https://lore.kernel.org/r/20210407095527.2771582-1-wak@google.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Hi,
The older API used to supply additional device properties for the
devices - so mainly the function device_add_properties() - is going to
be removed. The reason why the API will be removed is because it gives
false impression that the properties are assigned directly to the
devices, which has actually never been the case - the properties have
always been assigned to a software fwnode which was then just directly
linked with the device when the old API was used. By only accepting
device properties instead of complete software nodes, the subsystems
remove any change of taking advantage of the other features the
software nodes have.
The change that is required from the spi subsystem and the drivers is
trivial. Basically only the "properties" member in struct
spi_board_info, which was a pointer to struct property_entry, is
replaced with a pointer to a complete software node.
thanks,
Heikki Krogerus (4):
spi: Add support for software nodes
ARM: pxa: icontrol: Constify the software node
ARM: pxa: zeus: Constify the software node
spi: Remove support for dangling device properties
arch/arm/mach-pxa/icontrol.c | 12 ++++++++----
arch/arm/mach-pxa/zeus.c | 6 +++++-
drivers/spi/spi.c | 21 ++++++---------------
include/linux/spi/spi.h | 7 +++----
4 files changed, 22 insertions(+), 24 deletions(-)
--
2.30.1
base-commit: a38fd87484
Making it possible for the drivers to assign complete
software fwnodes to the devices instead of only the device
properties in those nodes.
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20210303152814.35070-2-heikki.krogerus@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
The 'delay' field in the spi_transfer struct is meant to replace the
'delay_usecs' field. However some cleanup was required to remove the
uses of 'delay_usecs'. Now that it's been cleaned up, we can remove it
from the kernel tree.
Signed-off-by: Alexandru Ardelean <aardelean@deviqon.com>
Link: https://lore.kernel.org/r/20210308145502.1075689-10-aardelean@deviqon.com
Signed-off-by: Mark Brown <broonie@kernel.org>
The main focus of this release from a framework point of view has been
spi-mem where we've acquired support for a few new hardware features
which enable better performance on suitable hardware. Otherwise mostly
thanks to Arnd's cleanup efforts on old platforms we've removed several
obsolete drivers which just about balance out the newer drivers we've
added this cycle.
- Allow drivers to flag if they are unidirectional.
- Support for DTR mode and hardware acceleration of dummy cycles in spi-mem.
- Support for Allwinder H616, Intel Lightning Mountain, nVidia Tegra
QuadSPI, Realtek RTL838x and RTL839x.
- Removal of obsolute EFM32, Txx9 and SIRF Prima and Atlas drivers.
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Merge tag 'spi-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi
Pull spi updates from Mark Brown:
"The main focus of this release from a framework point of view has been
spi-mem where we've acquired support for a few new hardware features
which enable better performance on suitable hardware.
Otherwise mostly thanks to Arnd's cleanup efforts on old platforms
we've removed several obsolete drivers which just about balance out
the newer drivers we've added this cycle.
Summary:
- Allow drivers to flag if they are unidirectional.
- Support for DTR mode and hardware acceleration of dummy cycles in
spi-mem.
- Support for Allwinder H616, Intel Lightning Mountain, nVidia Tegra
QuadSPI, Realtek RTL838x and RTL839x.
- Removal of obsolete EFM32, Txx9 and SIRF Prima and Atlas drivers"
* tag 'spi-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi: (76 commits)
spi: Skip zero-length transfers in spi_transfer_one_message()
spi: dw: Avoid stack content exposure
spi: cadence-quadspi: Use spi_mem_dtr_supports_op()
spi: spi-mem: add spi_mem_dtr_supports_op()
spi: atmel-quadspi: Disable the QSPI IP at suspend()
spi: pxa2xx: Add IDs for the controllers found on Intel Lynxpoint
spi: pxa2xx: Fix the controller numbering for Wildcat Point
spi: Change provied to provided in the file spi.h
spi: mediatek: add set_cs_timing support
spi: support CS timing for HW & SW mode
spi: add power control when set_cs_timing
spi: stm32: make spurious and overrun interrupts visible
spi: stm32h7: replace private SPI_1HZ_NS with NSEC_PER_SEC
spi: stm32: defer probe for reset
spi: stm32: driver uses reset controller only at init
spi: stm32h7: ensure message are smaller than max size
spi: stm32: use bitfield macros
spi: stm32: do not mandate cs_gpio
spi: stm32: properly handle 0 byte transfer
spi: clps711xx: remove redundant white-space
...
With the introduction of 26751de25d ("spi: bcm2835: Micro-optimise
FIFO loops") it has become apparent that some users might initiate
zero-length SPI transfers. A fact the micro-optimization omitted, and
which turned out to cause crashes[1].
Instead of changing the micro-optimization itself, use a bigger hammer
and skip zero-length transfers altogether for drivers using the default
transfer_one_message() implementation.
Reported-by: Phil Elwell <phil@raspberrypi.com>
Fixes: 26751de25d ("spi: bcm2835: Micro-optimise FIFO loops")
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
[1] https://github.com/raspberrypi/linux/issues/4100
Link: https://lore.kernel.org/r/20210211180820.25757-1-nsaenzjulienne@suse.de
Signed-off-by: Mark Brown <broonie@kernel.org>
The double negative makes it hard to read "if (!ACPI_FAILURE(status))".
Replace it with "if (ACPI_SUCCESS(status))".
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
Acked-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The xfer waiting time is the result of xfer->len / xfer->speed_hz. This
patch makes the assumption of 100khz xfer speed if the xfer->speed_hz is
not assigned and stays 0. This avoids the divide by 0 issue and ensures
a reasonable tolerant waiting time.
Signed-off-by: Xu Yilun <yilun.xu@intel.com>
Link: https://lore.kernel.org/r/1609723749-3557-1-git-send-email-yilun.xu@intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
If spi->controller->max_speed_hz is zero, a non-zero spi->max_speed_hz
will be overwritten by zero. Make sure spi->controller->max_speed_hz
is not zero when clamping spi->max_speed_hz.
Put the spi->controller->max_speed_hz non-zero check higher in the if,
so that we avoid a superfluous init to zero when both spi->max_speed_hz
and spi->controller->max_speed_hz are zero.
Fixes: 9326e4f1e5 ("spi: Limit the spi device max speed to controller's max speed")
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20201216092321.413262-1-tudor.ambarus@microchip.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Transmit/receive only is a valid SPI mode. For example, the MOSI/TX line
might be missing from an ADC while for a DAC the MISO/RX line may be
optional. This patch adds these two new modes: SPI_NO_TX and
SPI_NO_RX. This way, the drivers will be able to identify if any of
these two lines is missing and to adjust the transfers accordingly.
Signed-off-by: Dragos Bogdan <dragos.bogdan@analog.com>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20201221152936.53873-2-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Shutdown bus function might be called on the unbound device, so add a
check if there is a driver before calling its shutdown function.
This fixes following kernel panic obserbed during system reboot:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000018
...
Call trace:
spi_shutdown+0x10/0x38
kernel_restart_prepare+0x34/0x40
kernel_restart+0x14/0x88
__do_sys_reboot+0x148/0x248
__arm64_sys_reboot+0x1c/0x28
el0_svc_common.constprop.3+0x74/0x198
do_el0_svc+0x20/0x98
el0_sync_handler+0x140/0x1a8
el0_sync+0x140/0x180
Code: f9403402 d1008041 f100005f 9a9f1021 (f9400c21)
---[ end trace 266c07205a2d632e ]---
Fixes: 9db34ee64c (spi: Use bus_type functions for probe, remove and shutdown)
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20201124131523.32287-1-m.szyprowski@samsung.com
Signed-off-by: Mark Brown <broonie@kernel.org>
I've discovered that due to the recent commit 49d7d695ca ("spi: dw:
Explicitly de-assert CS on SPI transfer completion") a concurrent usage of
the spidev devices with different chip-selects causes the "SPI transfer
timed out" error. The root cause of the problem has turned to be in a race
condition of the SPI-transfer execution procedure and the spi_setup()
method being called at the same time. In particular in calling the
spi_set_cs(false) while there is an SPI-transfer being executed. In my
case due to the commit cited above all CSs get to be switched off by
calling the spi_setup() for /dev/spidev0.1 while there is an concurrent
SPI-transfer execution performed on /dev/spidev0.0. Of course a situation
of the spi_setup() being called while there is an SPI-transfer being
executed for two different SPI peripheral devices of the same controller
may happen not only for the spidev driver, but for instance for MMC SPI +
some another device, or spi_setup() being called from an SPI-peripheral
probe method while some other device has already been probed and is being
used by a corresponding driver...
Of course I could have provided a fix affecting the DW APB SSI driver
only, for instance, by creating a mutual exclusive access to the set_cs
callback and setting/clearing only the bit responsible for the
corresponding chip-select. But after a short research I've discovered that
the problem most likely affects a lot of the other drivers:
- drivers/spi/spi-sun4i.c - RMW the chip-select register;
- drivers/spi/spi-rockchip.c - RMW the chip-select register;
- drivers/spi/spi-qup.c - RMW a generic force-CS flag in a CSR.
- drivers/spi/spi-sifive.c - set a generic CS-mode flag in a CSR.
- drivers/spi/spi-bcm63xx-hsspi.c - uses an internal mutex to serialize
the bus config changes, but still isn't protected from the race
condition described above;
- drivers/spi/spi-geni-qcom.c - RMW a chip-select internal flag and set the
CS state in HW;
- drivers/spi/spi-orion.c - RMW a chip-select register;
- drivers/spi/spi-cadence.c - RMW a chip-select register;
- drivers/spi/spi-armada-3700.c - RMW a chip-select register;
- drivers/spi/spi-lantiq-ssc.c - overwrites the chip-select register;
- drivers/spi/spi-sun6i.c - RMW a chip-select register;
- drivers/spi/spi-synquacer.c - RMW a chip-select register;
- drivers/spi/spi-altera.c - directly sets the chip-select state;
- drivers/spi/spi-omap2-mcspi.c - RMW an internally cached CS state and
writes it to HW;
- drivers/spi/spi-mt65xx.c - RMW some CSR;
- drivers/spi/spi-jcore.c - directly sets the chip-selects state;
- drivers/spi/spi-mt7621.c - RMW a chip-select register;
I could have missed some drivers, but a scale of the problem is obvious.
As you can see most of the drivers perform an unprotected
Read-modify-write chip-select register modification in the set_cs callback.
Seeing the spi_setup() function is calling the spi_set_cs() and it can be
executed concurrently with SPI-transfers exec procedure, which also calls
spi_set_cs() in the SPI core spi_transfer_one_message() method, the race
condition of the register modification turns to be obvious.
To sum up the problem denoted above affects each driver for a controller
having more than one chip-select lane and which:
1) performs the RMW to some CS-related register with no serialization;
2) directly disables any CS on spi_set_cs(dev, false).
* the later is the case of the DW APB SSI driver.
The controllers which equipped with a single CS theoretically can also
experience the problem, but in practice will not since normally the
spi_setup() isn't called concurrently with the SPI-transfers executed on
the same SPI peripheral device.
In order to generically fix the denoted bug I'd suggest to serialize an
access to the controller IO by taking the IO mutex in the spi_setup()
callback. The mutex is held while there is an SPI communication going on
on the SPI-bus of the corresponding SPI-controller. So calling the
spi_setup() method and disabling/updating the CS state within it would be
safe while there is no any SPI-transfers being executed. Also note I
suppose it would be safer to protect the spi_controller->setup() callback
invocation too, seeing some of the SPI-controller drivers update a HW
state in there.
Fixes: 49d7d695ca ("spi: dw: Explicitly de-assert CS on SPI transfer completion")
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20201117094517.5654-1-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Mark Brown <broonie@kernel.org>
The driver core ignores the return value of struct device_driver::remove
(because in general there is nothing that can be done about that). So
add a warning when an spi driver returns an error.
This simplifies the quest to make struct device_driver::remove return void.
A consequent change would be to make struct spi_driver::remove return void,
but I'm keeping this quest for later (or someone else).
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20201119161604.2633521-3-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>
The eventual goal is to get rid of the callbacks in struct
device_driver. Other than not using driver callbacks there should be no
side effect of this patch.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20201119161604.2633521-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>
Consider an spi driver with a .probe but without a .remove callback (e.g.
rtc-ds1347). The function spi_drv_probe() is called to bind a device and
so dev_pm_domain_attach() is called. As there is no remove callback
spi_drv_remove() isn't called at unbind time however and so calling
dev_pm_domain_detach() is missed and the pm domain keeps active.
To fix this always use both spi_drv_probe() and spi_drv_remove() and
make them handle the respective callback not being set. This has the
side effect that for a (hypothetical) driver that has neither .probe nor
remove the clk and pm domain setup is done.
Fixes: 33cf00e570 ("spi: attach/detach SPI device to the ACPI power domain")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20201119161604.2633521-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>
SPI driver probing currently comprises two steps, whereas removal
comprises only one step:
spi_alloc_master()
spi_register_controller()
spi_unregister_controller()
That's because spi_unregister_controller() calls device_unregister()
instead of device_del(), thereby releasing the reference on the
spi_controller which was obtained by spi_alloc_master().
An SPI driver's private data is contained in the same memory allocation
as the spi_controller struct. Thus, once spi_unregister_controller()
has been called, the private data is inaccessible. But some drivers
need to access it after spi_unregister_controller() to perform further
teardown steps.
Introduce devm_spi_alloc_master() and devm_spi_alloc_slave(), which
release a reference on the spi_controller struct only after the driver
has unbound, thereby keeping the memory allocation accessible. Change
spi_unregister_controller() to not release a reference if the
spi_controller was allocated by one of these new devm functions.
The present commit is small enough to be backportable to stable.
It allows fixing drivers which use the private data in their ->remove()
hook after it's been freed. It also allows fixing drivers which neglect
to release a reference on the spi_controller in the probe error path.
Long-term, most SPI drivers shall be moved over to the devm functions
introduced herein. The few that can't shall be changed in a treewide
commit to explicitly release the last reference on the controller.
That commit shall amend spi_unregister_controller() to no longer release
a reference, thereby completing the migration.
As a result, the behaviour will be less surprising and more consistent
with subsystems such as IIO, which also includes the private data in the
allocation of the generic iio_dev struct, but calls device_del() in
iio_device_unregister().
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/272bae2ef08abd21388c98e23729886663d19192.1605121038.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@kernel.org>
Mark Brown
Vinod Koul
Colin Ian King
Sebastian Reichel
Marco Felsch
Greg Kroah-Hartman
Andy Shevchenko
Saravana Kannan
Leilk Liu
Charles Keepax
Joe Burmeister
David Bauer
Tian Tao
William A. Kennington III
Heikki Krogerus
Alexandru Ardelean
Linus Torvalds
Nicolas Saenz Julienne
Bjorn Helgaas
Xu Yilun
Tudor Ambarus
Dragos Bogdan
Marek Szyprowski
Serge Semin
Uwe Kleine-König
Lukas Wunner