When in DMA mode, the BCM2835 SPI controller requires that the FIFO is
accessed in 4 byte chunks. This rule is not fulfilled if a transfer
consists of multiple sglist entries, one per page, and the first entry
starts in the middle of a page with an offset not a multiple of 4.
The driver currently falls back to programmed I/O for such transfers,
incurring a significant performance penalty.
Overcome this hardware limitation by transferring the first few bytes of
a transfer without DMA such that the remainder of the first sglist entry
becomes a multiple of 4. Specifics are provided in kerneldoc comments.
An alternative approach would have been to split transfers in the
->prepare_message hook, but this may necessitate two transfers per page,
defeating the goal of clustering multiple pages together in a single
transfer for efficiency. E.g. if the first TX sglist entry's length is
23 and the first RX's is 40, the first transfer would send and receive
23 bytes, the second 40 - 23 = 17 bytes, the third 4096 - 17 = 4079
bytes, the fourth 4096 - 4079 = 17 bytes and so on. In other words,
O(n) transfers are necessary (n = number of sglist entries), whereas
the algorithm implemented herein only requires O(1) additional work.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Mathias Duckeck <m.duckeck@kunbus.de>
Cc: Frank Pavlic <f.pavlic@kunbus.de>
Cc: Martin Sperl <kernel@martin.sperl.org>
Cc: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Document the driver's data structure to lower the barrier to entry for
contributors.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Mathias Duckeck <m.duckeck@kunbus.de>
Cc: Frank Pavlic <f.pavlic@kunbus.de>
Cc: Martin Sperl <kernel@martin.sperl.org>
Cc: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Commit a30a555d74 ("spi: bcm2835: transform native-cs to gpio-cs on
first spi_setup") disabled the use of hardware-controlled native Chip
Select in favour of software-controlled GPIO Chip Select but left code
to support the former untouched. Remove it to simplify the driver and
ease the addition of new features and further optimizations.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Mathias Duckeck <m.duckeck@kunbus.de>
Cc: Frank Pavlic <f.pavlic@kunbus.de>
Cc: Martin Sperl <kernel@martin.sperl.org>
Cc: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
If a DMA transfer finishes orderly right when spi_transfer_one_message()
determines that it has timed out, the callbacks bcm2835_spi_dma_done()
and bcm2835_spi_handle_err() race to call dmaengine_terminate_all(),
potentially leading to double termination.
Prevent by atomically changing the dma_pending flag before calling
dmaengine_terminate_all().
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Fixes: 3ecd37edaa ("spi: bcm2835: enable dma modes for transfers meeting certain conditions")
Cc: stable@vger.kernel.org # v4.2+
Cc: Mathias Duckeck <m.duckeck@kunbus.de>
Cc: Frank Pavlic <f.pavlic@kunbus.de>
Cc: Martin Sperl <kernel@martin.sperl.org>
Cc: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
If submission of a DMA TX transfer succeeds but submission of the
corresponding RX transfer does not, the BCM2835 SPI driver terminates
the TX transfer but neglects to reset the dma_pending flag to false.
Thus, if the next transfer uses interrupt mode (because it is shorter
than BCM2835_SPI_DMA_MIN_LENGTH) and runs into a timeout,
dmaengine_terminate_all() will be called both for TX (once more) and
for RX (which was never started in the first place). Fix it.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Fixes: 3ecd37edaa ("spi: bcm2835: enable dma modes for transfers meeting certain conditions")
Cc: stable@vger.kernel.org # v4.2+
Cc: Mathias Duckeck <m.duckeck@kunbus.de>
Cc: Frank Pavlic <f.pavlic@kunbus.de>
Cc: Martin Sperl <kernel@martin.sperl.org>
Cc: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
The IRQ handler bcm2835_spi_interrupt() first reads as much as possible
from the RX FIFO, then writes as much as possible to the TX FIFO.
Afterwards it decides whether the transfer is finished by checking if
the TX FIFO is empty.
If very few bytes were written to the TX FIFO, they may already have
been transmitted by the time the FIFO's emptiness is checked. As a
result, the transfer will be declared finished and the chip will be
reset without reading the corresponding received bytes from the RX FIFO.
The odds of this happening increase with a high clock frequency (such
that the TX FIFO drains quickly) and either passing "threadirqs" on the
command line or enabling CONFIG_PREEMPT_RT_BASE (such that the IRQ
handler may be preempted between filling the TX FIFO and checking its
emptiness).
Fix by instead checking whether rx_len has reached zero, which means
that the transfer has been received in full. This is also more
efficient as it avoids one bus read access per interrupt. Note that
bcm2835_spi_transfer_one_poll() likewise uses rx_len to determine
whether the transfer has finished.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Fixes: e34ff011c7 ("spi: bcm2835: move to the transfer_one driver model")
Cc: stable@vger.kernel.org # v4.1+
Cc: Mathias Duckeck <m.duckeck@kunbus.de>
Cc: Frank Pavlic <f.pavlic@kunbus.de>
Cc: Martin Sperl <kernel@martin.sperl.org>
Cc: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
This patch implements power management callback function for USART as
SPI driver.
Signed-off-by: Radu Pirea <radu_nicolae.pirea@upb.ro>
Signed-off-by: Mark Brown <broonie@kernel.org>
The compiler has no way to know that rsize 1 or 2 are the only valid
values. Also simplify the code a bit with early return.
The warning was:
drivers/spi/spi-npcm-pspi.c:215:6: warning: 'val' may be used uninitialized in this function [-Wmaybe-uninitialized]
Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Mark Brown <broonie@kernel.org>
This patch adds a DT binding documentation for the MT7629 soc.
Signed-off-by: Leilk Liu <leilk.liu@mediatek.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
There is an IS_ERR() vs PTR_ERR() typo here. The current code returns 1
but we want to return the negative error code.
Fixes: 2a22f1b30c ("spi: npcm: add NPCM PSPI controller driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
I've been wondering still about omap2-mcspi related suspend and resume
flakeyness and looks like we're missing calls to spi_master_suspend()
and spi_master_resume(). Adding those and using pm_runtime_force_suspend()
and pm_runtime_force_resume() makes things work for suspend and resume
and allows us to stop using noirq suspend and resume.
And while at it, let's use SET_SYSTEM_SLEEP_PM_OPS to simplify things
further.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
The refactoring done as part of adding the core support for handling
waiting for slave transfer dropped a conditional which meant that we
started waiting for completion of all transfers, not just those that the
controller asked for. This caused hangs and massive delays on platforms
that don't need the core delay. Re-add the delay to fix this.
Fixes: 810923f3bf (spi: Deal with slaves that return from transfer_one() unfinished)
Reported-by: Tony Lindgren <tony@atomide.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
drivers/spi/spi-npcm-pspi.c:470:3-8: No need to set .owner here. The core will do it.
Remove .owner field if calls are used which set it automatically
Generated by: scripts/coccinelle/api/platform_no_drv_owner.cocci
Fixes: 2a22f1b30c ("spi: npcm: add NPCM PSPI controller driver")
CC: Tomer Maimon <tmaimon77@gmail.com>
Signed-off-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
The license text is specifying GPL v2 or later but the MODULE_LICENSE
is set to GPL v2 which means GNU Public License v2 only. So choose the
license text as the correct one.
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Acked-by: Florian Kauer <florian.kauer@koalo.de>
Acked-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
The u32 variable csgpio is being checked for an error return
from the call to of_get_named_gpio, however, since this is unsigned
this comparison will always be false. Fix this by making csgpio an
int and fix up the %u format specifiers to %d accordingly.
Detected by CoverityScan, CID#1475476 ("Unsigned compared against 0")
Fixes: 2a22f1b30c ("spi: npcm: add NPCM PSPI controller driver")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Added device tree binding documentation for Nuvoton BMC
NPCM Peripheral SPI controller.
Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Do not deselect cs when cs_change is set for the last transfer in the
message. In this case, cs_change indicates that cs should stay selected
until the next transfer.
Signed-off-by: Fredrik Ternerot <fredrikt@axis.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
There doesn't seem to be a way to empty TXFIFO on MMP2. The datasheet is
super-secret and the method described in Armada 16x manual won't work:
"The TXFIFO and RXFIFO are cleared to 0b0 when the SSPx port is reset or
disabled (by writing a 0b0 to the <Synchronous Serial Port Enable> field
in the SSP Control Register 0)."
# devmem 0xd4037008 # read SSSR
0x0000F204
# devmem 0xd4037000 32 0x07 # SSE off in SSCR0
# devmem 0xd4037000 32 0x87 # SSE on
# devmem 0xd4037008
0x0000F204
^ TXFIFO level is still 2. Sigh.
The OLPC 1.75 boot firmware leaves two bytes in the TXFIFO. Those are
basically throwaway bytes used in response to the messages from the EC.
The OLPC kernel copes with this by power-cycling the hardware. Perhaps
the firmware should do this instead.
Other than that, there's not much we can do other than complain loudly
until the garbage gets drained and discard the actual data... For the
OLPC EC this will work just fine and pushing more data to TXFIFO would
break further transactions.
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Mark Brown <broonie@kernel.org>
Strobe a GPIO line when the slave TX FIFO is filled. This is how the
Embedded Controller on an OLPC XO-1.75 machine, that happens to be a SPI
master, learns that it can initiate a transaction.
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Tested-by: Pavel Machek <pavel@ucw.cz>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>
This this is used to let the SPI master know that our FIFO is filled and
we're ready to service a transfer. Only useful in slave mode.
A signal like this is used by an embedded controller on a OLPC XO 1.75
machine, that happens to be a SPI master.
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Acked-by: Pavel Machek <pavel@ucw.cz>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>
Tested on an OLPC XO-1.75 machine, where the Embedded Controller happens
to be a SPI master.
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Mark Brown <broonie@kernel.org>
Some drivers, such as spi-pxa2xx return from the transfer_one callback
immediately, idicating that the transfer will be finished asynchronously.
Normally, spi_transfer_one_message() synchronously waits for the
transfer to finish with wait_for_completion_timeout(). For slaves, we
don't want the transaction to time out as it can complete in a long time
in future. Use wait_for_completion_interruptible() instead.
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Acked-by: Pavel Machek <pavel@ucw.cz>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>
This is used to indicate that the chip attached to this controller is a SPI
master.
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>
Add r8a77470 to the list of examples with soctypes.
No driver change is needed as "renesas,qspi" will activate
the right code within the corresponding driver.
Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Enable McSPI driver to be built for K3 platforms, to support McSPI on
AM654 SoC of K3 family.
Signed-off-by: Vignesh R <vigneshr@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
AM654 SoC has same McSPI IP as OMAP2+ platforms. Add new compatible to
support McSPI on AM654 SoC.
Signed-off-by: Vignesh R <vigneshr@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Document the bindings used by the Macronix controller.
Signed-off-by: Mason Yang <masonccyang@mxic.com.tw>
Reviewed-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Add a driver for Macronix SPI controller IP.
Signed-off-by: Mason Yang <masonccyang@mxic.com.tw>
Reviewed-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
We should get 'driver_data' from 'struct device' directly. Going via
platform_device is an unneeded step back and forth.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
We should get 'driver_data' from 'struct device' directly. Going via
platform_device is an unneeded step back and forth.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
We should get 'driver_data' from 'struct device' directly. Going via
platform_device is an unneeded step back and forth.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
In commit 7662d1dc17d4 ("spi: uniphier: fix incorrect property items")
addressing properties of #address-cells and #size-cells were removed.
Since it is not necessary to remove them, they are back again.
Signed-off-by: Keiji Hayashibara <hayashibara.keiji@socionext.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit fixes incorrect property because it was different
from the actual.
The parameters of '#address-cells' and '#size-cells' were removed,
and 'interrupts', 'pinctrl-names' and 'pinctrl-0' were added.
Fixes: 4dcd5c2781 ("spi: add DT bindings for UniPhier SPI controller")
Signed-off-by: Keiji Hayashibara <hayashibara.keiji@socionext.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Re-arrange existing APIs in probe function to
avoid using goto and remove redundant variables.
Signed-off-by: Alok Chauhan <alokc@codeaurora.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
fixed the nitpicks.
Signed-off-by: Alok Chauhan <alokc@codeaurora.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Some SoC share one irq number between DSPI controllers.
For example, on the LX2160 board, DSPI0 and DSPI1 share one irq number.
In this case, only one DSPI controller can register successfully,
and others will fail.
Signed-off-by: Chuanhua Han <chuanhua.han@nxp.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
This patch adds a DT binding documentation for the MT8183 soc.
Signed-off-by: Leilk Liu <leilk.liu@mediatek.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Intel LPSS private register restoring in spi-pxa2xx.c: pxa2xx_spi_resume()
was added before there was no any other code restoring them. This was
changed after following commits for previous and current LPSS platforms:
c78b083066 ("ACPI / LPSS: custom power domain for LPSS")
41a3da2b8e ("mfd: intel-lpss: Save register context on suspend")
However there is one caveat: There is no LPSS private register context
save/restore for the Intel Lynxpoint in the Linux kernel code.
I did some debugging on one Lynxpoint based device I have and on it the
LPSS register context is not lost over suspend/resume cycle (s2idle).
Which happens for instance on Intel Braswell. I'm speculating but I guess
either firmware does it or the LPSS is kept always on Lynxpoint.
Given that we haven't needed to implement Lynxpoint LPSS I2C or UART
private register context save/restore over four years time I think we are
safe to remove this LPSS private register restoring during resume here.
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Add missing support for lsb-first mode.
Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
The hardware supports 4, 8 and 16bit spi words,
so add the missing support for 4bit words.
Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
Register an interrupt handler to fill/empty the
tx and rx fifos rather than busy-looping.
Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
Now that we no longer potentially change spi clock
at runtime we can precompute the rx sample delay
at probe time rather than for each transfer.
Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
The driver previously checked each transfer if the
requested speed was higher than possible with the
current spi clock rate and raised the clock rate
accordingly.
However, there is no check to see if the spi clock
was actually set that high and no way to dynamically
lower the spi clock rate again.
So it seems any potiential users of this functionality
are better off just setting the spi clock rate at init
using the assigned-clock-rates devicetree property.
Removing this dynamic spi clock rate raising allows
us let the spi framework handle min/max speeds
for us.
Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
We only need to know if we're using dma when setting
up the transfer, so just use a local variable for
that.
Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
