The interaction with the controller message queue and its corresponding
auxiliary flags and variables requires the use of the queue_lock which is
costly. Since spi_sync will transfer the complete message anyway, and not
return until it is finished, there is no need to put the message into the
queue if the queue is empty. This can save a lot of overhead.
As an example of how significant this is, when using the MCP2518FD SPI CAN
controller on a i.MX8MM SoC, the time during which the interrupt line
stays active (during 3 relatively short spi_sync messages), is reduced
from 98us to 72us by this patch.
Signed-off-by: David Jander <david@protonic.nl>
Link: https://lore.kernel.org/r/20220621061234.3626638-3-david@protonic.nl
Signed-off-by: Mark Brown <broonie@kernel.org>
On 32 bit systems, the following kernel BUG is hit:
BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1
caller is debug_smp_processor_id+0x18/0x24
CPU: 1 PID: 1 Comm: swapper/0 Not tainted 5.19.0-rc1-00001-g6ae0aec8a366 #181
Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
Backtrace:
dump_backtrace from show_stack+0x20/0x24
r7:81024ffd r6:00000000 r5:81024ffd r4:60000013
show_stack from dump_stack_lvl+0x60/0x78
dump_stack_lvl from dump_stack+0x14/0x1c
r7:81024ffd r6:80f652de r5:80bec180 r4:819a2500
dump_stack from check_preemption_disabled+0xc8/0xf0
check_preemption_disabled from debug_smp_processor_id+0x18/0x24
r8:8119b7e0 r7:81205534 r6:819f5c00 r5:819f4c00 r4:c083d724
debug_smp_processor_id from __spi_sync+0x78/0x220
__spi_sync from spi_sync+0x34/0x4c
r10:bb7bf4e0 r9:c083d724 r8:00000007 r7:81a068c0 r6:822a83c0 r5:c083d724
r4:819f4c00
spi_sync from spi_mem_exec_op+0x338/0x370
r5:000000b4 r4:c083d910
spi_mem_exec_op from spi_nor_read_id+0x98/0xdc
r10:bb7bf4e0 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:82358040
r4:819f7c40
spi_nor_read_id from spi_nor_detect+0x38/0x114
r7:82358040 r6:00000000 r5:819f7c40 r4:819f7c40
spi_nor_detect from spi_nor_scan+0x11c/0xbec
r10:bb7bf4e0 r9:00000000 r8:00000000 r7:c083da4c r6:00000000 r5:00010101
r4:819f7c40
spi_nor_scan from spi_nor_probe+0x10c/0x2d0
r10:bb7bf4e0 r9:bb7bf4d0 r8:00000000 r7:819f4c00 r6:00000000 r5:00000000
r4:819f7c40
per-cpu access needs to be guarded against preemption.
Fixes: 6598b91b5a ("spi: spi.c: Convert statistics to per-cpu u64_stats_t")
Reported-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: David Jander <david@protonic.nl>
Tested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Link: https://lore.kernel.org/r/20220609121334.2984808-1-david@protonic.nl
Signed-off-by: Mark Brown <broonie@kernel.org>
This change gives a dramatic performance improvement in the hot path,
since many costly spin_lock_irqsave() calls can be avoided.
On an i.MX8MM system with a MCP2518FD CAN controller connected via SPI,
the time the driver takes to handle interrupts, or in other words the time
the IRQ line of the CAN controller stays low is mainly dominated by the
time it takes to do 3 relatively short sync SPI transfers. The effect of
this patch is a reduction of this time from 136us down to only 98us.
Suggested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David Jander <david@protonic.nl>
Link: https://lore.kernel.org/r/20220524091808.2269898-1-david@protonic.nl
Signed-off-by: Mark Brown <broonie@kernel.org>
Pull driver core updates from Greg KH:
"Here is the set of driver core changes for 5.19-rc1.
Lots of tiny driver core changes and cleanups happened this cycle, but
the two major things are:
- firmware_loader reorganization and additions including the ability
to have XZ compressed firmware images and the ability for userspace
to initiate the firmware load when it needs to, instead of being
always initiated by the kernel. FPGA devices specifically want this
ability to have their firmware changed over the lifetime of the
system boot, and this allows them to work without having to come up
with yet-another-custom-uapi interface for loading firmware for
them.
- physical location support added to sysfs so that devices that know
this information, can tell userspace where they are located in a
common way. Some ACPI devices already support this today, and more
bus types should support this in the future.
Smaller changes include:
- driver_override api cleanups and fixes
- error path cleanups and fixes
- get_abi script fixes
- deferred probe timeout changes.
It's that last change that I'm the most worried about. It has been
reported to cause boot problems for a number of systems, and I have a
tested patch series that resolves this issue. But I didn't get it
merged into my tree before 5.18-final came out, so it has not gotten
any linux-next testing.
I'll send the fixup patches (there are 2) as a follow-on series to this
pull request.
All have been tested in linux-next for weeks, with no reported issues
other than the above-mentioned boot time-outs"
* tag 'driver-core-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (55 commits)
driver core: fix deadlock in __device_attach
kernfs: Separate kernfs_pr_cont_buf and rename_lock.
topology: Remove unused cpu_cluster_mask()
driver core: Extend deferred probe timeout on driver registration
MAINTAINERS: add Russ Weight as a firmware loader maintainer
driver: base: fix UAF when driver_attach failed
test_firmware: fix end of loop test in upload_read_show()
driver core: location: Add "back" as a possible output for panel
driver core: location: Free struct acpi_pld_info *pld
driver core: Add "*" wildcard support to driver_async_probe cmdline param
driver core: location: Check for allocations failure
arch_topology: Trace the update thermal pressure
kernfs: Rename kernfs_put_open_node to kernfs_unlink_open_file.
export: fix string handling of namespace in EXPORT_SYMBOL_NS
rpmsg: use local 'dev' variable
rpmsg: Fix calling device_lock() on non-initialized device
firmware_loader: describe 'module' parameter of firmware_upload_register()
firmware_loader: Move definitions from sysfs_upload.h to sysfs.h
firmware_loader: Fix configs for sysfs split
selftests: firmware: Add firmware upload selftests
...
Pull spi fixes from Mark Brown:
"A couple of fixes that came in during the merge window: a driver fix
for spurious timeouts in the fsi driver and an improvement to make the
core display error messages for transfer_one_message() to help people
debug things"
* tag 'spi-fix-v5.19-rc0' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi:
spi: core: Display return code when failing to transfer message
spi: fsi: Fix spurious timeout
Pull spi updates from Mark Brown:
"This is quite a quiet release but some new drivers mean that the
diffstat is fairly large. The new drivers include the aspeed driver
which is migrated from MTD as part of the ongoing move of controllers
with specialised support for SPI flashes into the SPI subsystem.
- Support for devices which flip CPHA during recieve only transfers
(eg, if MOSI and MISO have inverted polarity).
- Overhaul of the i.MX driver, including the addition of PIO support
for better performance on small transfers.
- Migration of the Aspeed driver from MTD.
- Support for Aspeed AST2400, Ingenic JZ4775 and X1/2000 and MediaTek
IPM and SFI"
* tag 'spi-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi: (84 commits)
spi: spi-au1550: replace ternary operator with min()
mtd: spi-nor: aspeed: set the decoding size to at least 2MB for AST2600
spi: aspeed: Calibrate read timings
spi: aspeed: Add support for the AST2400 SPI controller
spi: aspeed: Workaround AST2500 limitations
spi: aspeed: Adjust direct mapping to device size
spi: aspeed: Add support for direct mapping
spi: spi-mem: Convert Aspeed SMC driver to spi-mem
spi: Convert the Aspeed SMC controllers device tree binding
spi: spi-cadence: Update ISR status variable type to irqreturn_t
spi: Doc fix - Describe add_lock and dma_map_dev in spi_controller
spi: cadence-quadspi: Handle spi_unregister_master() in remove()
spi: stm32-qspi: Remove SR_BUSY bit check before sending command
spi: stm32-qspi: Always check SR_TCF flags in stm32_qspi_wait_cmd()
spi: stm32-qspi: Fix wait_cmd timeout in APM mode
spi: cadence-quadspi: remove unnecessary (void *) casts
spi: cadence-quadspi: Add missing blank line in cqspi_request_mmap_dma()
spi: spi-imx: mx51_ecspi_prepare_message(): skip writing MX51_ECSPI_CONFIG register if unchanged
spi: spi-imx: add PIO polling support
spi: spi-imx: replace struct spi_imx_data::bitbang by pointer to struct spi_controller
...
On SPI device probe, the core will call spi_setup in spi_add_device
before the corresponding driver was probed. When this happens, the
bits_per_word member of the device is not yet set by the driver,
resulting in the default being set to 8 bits-per-word.
However some controllers do not support 8 bits-per-word at all, which
results in a failure when checking the bits-per-word validity.
In order to support these devices, skip the bits-per-word validity
check when it is not explicitly provided by drivers.
Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Link: https://lore.kernel.org/r/20220412122207.130181-1-paul.kocialkowski@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Pull ACPI updates from Rafael Wysocki:
"These revert a problematic commit from the 5.17 development cycle and
finalize the elimination of acpi_bus_get_device() that mostly took
place during the recent merge window.
Specifics:
- Revert an ACPI processor driver change related to cache
invalidation in acpi_idle_play_dead() that clearly was a mistake
and introduced user-visible regressions (Akihiko Odaki).
- Replace the last instance of acpi_bus_get_device() added during the
recent merge window and drop the function to prevent more users of
it from being added (Rafael Wysocki)"
* tag 'acpi-5.18-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
ACPI: bus: Eliminate acpi_bus_get_device()
Revert "ACPI: processor: idle: Only flush cache on entering C3"
Replace the last instance of acpi_bus_get_device(), added recently
by commit 87e59b36e5 ("spi: Support selection of the index of the
ACPI Spi Resource before alloc"), with acpi_fetch_acpi_dev() and
finally drop acpi_bus_get_device() that has no more users.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Mark Brown <broonie@kernel.org>
While computing sgs in spi_map_buf(), the data type
used in min_t() for max_seg_size is 'unsigned int' where
as that of ctlr->max_dma_len is 'size_t'.
min_t(unsigned int,x,y) gives wrong results if one of x/y is
'size_t'
Consider the below examples on a 64-bit machine (ie size_t is
64-bits, and unsigned int is 32-bit).
case 1) min_t(unsigned int, 5, 0x100000001);
case 2) min_t(size_t, 5, 0x100000001);
Case 1 returns '1', where as case 2 returns '5'. As you can see
the result from case 1 is wrong.
This patch fixes the above issue by using the data type of the
parameters that are used in min_t with maximum data length.
Fixes: commit 1a4e53d2fc ("spi: Fix invalid sgs value")
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Suggested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20220316175317.465-1-biju.das.jz@bp.renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Commit d40f0b6f2e instroduced last_cs_enable to avoid setting
chipselect if it's not necessary, but it also introduces a bug. The
chipselect may not be set correctly on multi-device SPI busses. The
reason is that we can't judge the chipselect by bool last_cs_enable,
since chipselect may be modified after other devices were accessed.
So we should record the specific state of chipselect in case of
confusion.
Signed-off-by: Yun Zhou <yun.zhou@windriver.com>
Link: https://lore.kernel.org/r/20220217141234.72737-1-yun.zhou@windriver.com
Signed-off-by: Mark Brown <broonie@kernel.org>
All drivers using GPIOs as chip select have been rewritten to use
GPIO descriptors passing the ->use_gpio_descriptors flag. Retire
the code and fields used by the legacy GPIO API.
Do not drop the ->use_gpio_descriptors flag: it now only indicates
that we want to use GPIOs in addition to native chip selects.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20220210231954.807904-1-linus.walleij@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Merge series from Uwe Kleine-König <u.kleine-koenig@pengutronix.de>:
this series goal is to change the spi remove callback's return value to void.
After numerous patches nearly all drivers already return 0 unconditionally.
The four first patches in this series convert the remaining three drivers to
return 0, the final patch changes the remove prototype and converts all
implementers.
base-commit: 26291c54e1
Move the cs_setup delay to the end of spi_set_cs.
From include/linux/spi/spi.h:
* @cs_setup: delay to be introduced by the controller after CS is
asserted
The cs_setup delay needs to happen *after* CS is asserted, that is, at
the end of spi_set_cs, not at the beginning. Otherwise we're just
delaying before the SPI transaction starts at all, which isn't very
useful.
No drivers use this right now, but that is likely to change soon with an
upcoming Apple SPI HID transport driver.
Fixes: 25093bdeb6 ("spi: implement SW control for CS times")
Signed-off-by: Hector Martin <marcan@marcan.st>
Link: https://lore.kernel.org/r/20211210170534.177139-1-marcan@marcan.st
Signed-off-by: Mark Brown <broonie@kernel.org>
Commit 6098475d4c ("spi: Fix deadlock when adding SPI controllers on
SPI buses") introduced a per-controller mutex. But mutex_unlock() of
said lock is called after the controller is already freed:
spi_unregister_controller(ctlr)
-> put_device(&ctlr->dev)
-> spi_controller_release(dev)
-> mutex_unlock(&ctrl->add_lock)
Move the put_device() after the mutex_unlock().
Fixes: 6098475d4c ("spi: Fix deadlock when adding SPI controllers on SPI buses")
Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Cc: stable@vger.kernel.org # v5.15
Link: https://lore.kernel.org/r/20211111083713.3335171-1-michael@walle.cc
Signed-off-by: Mark Brown <broonie@kernel.org>
Pull spi updates from Mark Brown:
"This is quite a quiet release for SPI, there's been a bit of cleanup
to the core from Uwe but nothing functionality wise.
We have added several new drivers, Cadence XSPI, Ingenic JZ47xx,
Qualcomm SC7280 and SC7180 and Xilinx Versal OSPI"
* tag 'spi-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi: (41 commits)
spi: Convert NXP flexspi to json schema
spi: spi-geni-qcom: Add support for GPI dma
spi: fsi: Fix contention in the FSI2SPI engine
spi: spi-rpc-if: Check return value of rpcif_sw_init()
spi: tegra210-quad: Put device into suspend on driver removal
spi: tegra20-slink: Put device into suspend on driver removal
spi: bcm-qspi: Fix missing clk_disable_unprepare() on error in bcm_qspi_probe()
spi: at91-usart: replacing legacy gpio interface for gpiod
spi: replace snprintf in show functions with sysfs_emit
spi: cadence: Add of_node_put() before return
spi: orion: Add of_node_put() before goto
spi: cadence-quadspi: fix dma_unmap_single() call
spi: tegra20: fix build with CONFIG_PM_SLEEP=n
spi: bcm-qspi: add support for 3-wire mode for half duplex transfer
spi: bcm-qspi: Add mspi spcr3 32/64-bits xfer mode
spi: Make several public functions private to spi.c
spi: Reorder functions to simplify the next commit
spi: Remove unused function spi_busnum_to_master()
spi: Move comment about chipselect check to the right place
spi: fsi: Print status on error
...
io_mutex is taken by spi_setup() and spi-mux's .setup() callback calls
spi_setup() which results in a nested lock of io_mutex.
add_lock is taken by spi_add_device(). The device_add() call in there
can result in calling spi-mux's .probe() callback which registers its
own spi controller which in turn results in spi_add_device() being
called again.
To fix this initialize the controller's locks already in
spi_alloc_controller() to give spi_mux_probe() a chance to set the
lockdep subclass.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20211013133710.2679703-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>
Currently we have a global spi_add_lock which we take when adding new
devices so that we can check that we're not trying to reuse a chip
select that's already controlled. This means that if the SPI device is
itself a SPI controller and triggers the instantiation of further SPI
devices we trigger a deadlock as we try to register and instantiate
those devices while in the process of doing so for the parent controller
and hence already holding the global spi_add_lock. Since we only care
about concurrency within a single SPI bus move the lock to be per
controller, avoiding the deadlock.
This can be easily triggered in the case of spi-mux.
Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
