When the driver is working in TCFQ/EOQ mode (i.e. interacts with the SPI
controller's FIFOs directly) the following sequence of operations
happens:
- The first byte of the tx buffer gets pushed to the TX FIFO (dspi->len
gets decremented). This triggers the train of interrupts that handle
the rest of the bytes.
- The dspi_interrupt handles a TX confirmation event. It reads the newly
available byte from the RX FIFO, checks the dspi->len exit condition,
and if there's more to be done, it kicks off the next interrupt in the
train by writing the next byte to the TX FIFO.
Now the problem is that the wait queue is woken up one byte too early,
because dspi->len becomes 0 as soon as the byte has been pushed into the
TX FIFO. Its interrupt has not yet been processed and the RX byte has
not been put from the FIFO into the buffer.
Depending on the timing of the wait queue wakeup vs the handling of the
last dspi_interrupt, it can happen that the main SPI message pump thread
has already returned back into the spi_device driver. When the rx buffer
is on stack (which it can be, because in this mode, the DSPI doesn't do
DMA), the last interrupt will perform a memory write into an rx buffer
that has been freed. This manifests as stack corruption.
The solution is to only wake up the wait queue when dspi_rxtx says so,
i.e. after it has processed the last TX confirmation interrupt and
collected the last RX byte.
Fixes: c55be30591 ("spi: spi-fsl-dspi: Use poll mode in case the platform IRQ is missing")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190903105708.32273-1-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Add Nuvoton NPCM BMC Flash Interface Unit(FIU) SPI master
controller driver using SPI-MEM interface.
The FIU supports single, dual or quad communication interface.
the FIU controller can operate in following modes:
- User Mode Access(UMA): provides flash access by using an
indirect address/data mechanism.
- direct rd/wr mode: maps the flash memory into the core
address space.
- SPI-X mode: used for an expansion bus to an ASIC or CPLD.
Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
Link: https://lore.kernel.org/r/20190828142513.228556-3-tmaimon77@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This converts the BCM2835 SPI master driver to use GPIO
descriptors for chip select handling.
The BCM2835 driver was relying on the core to drive the
CS high/low so very small changes were needed for this
part. If it managed to request the CS from the device tree
node, all is pretty straight forward.
However for native GPIOs this driver has a quite unorthodox
loopback to request some GPIOs from the SoC GPIO chip by
looking it up from the device tree using gpiochip_find()
and then offseting hard into its numberspace. This has
been augmented a bit by using gpiochip_request_own_desc()
but this code really needs to be verified. If "native CS"
is actually an SoC GPIO, why is it even done this way?
Should this GPIO not just be defined in the device tree
like any other CS GPIO? I'm confused.
Cc: Lukas Wunner <lukas@wunner.de>
Cc: Stefan Wahren <stefan.wahren@i2se.com>
Cc: Martin Sperl <kernel@martin.sperl.org>
Cc: Chris Boot <bootc@bootc.net>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20190804003852.1312-1-linus.walleij@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>
This converts the Freescale SPI master driver to use GPIO
descriptors for chip select handling.
The Freescale (fsl) driver has a lot of quirks to look up
"gpios" rather than "cs-gpios" from the device tree.
After the prior patch that will make gpiolib return the
GPIO descriptor for "gpios" in response to a request for
"cs-gpios", this code can be cut down quite a bit.
The driver has custom handling of chip select rather
than using the core (which may be possible but not
done in this patch) so it still needs to refer directly
to spi->cs_gpiod to set the chip select.
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: NXP Linux Team <linux-imx@nxp.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20190804003539.985-1-linus.walleij@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>
On platforms like LS1021A which use TCFQ mode, an interrupt needs to be
processed after each byte is TXed/RXed. I tried to make the DSPI
implementation on this SoC operate in other, more efficient modes (EOQ,
DMA) but it looks like it simply isn't possible.
Therefore allow the driver to operate in poll mode, to ease a bit of
this absurd amount of IRQ load generated in TCFQ mode. Doing so reduces
both the net time it takes to transmit a SPI message, as well as the
inter-frame jitter that occurs while doing so.
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190822211514.19288-5-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
dspi->devtype_data is under the total control of the driver. Therefore,
a bad value is a driver bug and checking it at runtime (and during an
ISR, at that!) is pointless.
The second "else if" check is only for clarity (instead of a broader
"else") in case other transfer modes are added in the future. But the
printing is dead code and can be removed.
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190822211514.19288-4-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
The DSPI interrupt can be shared between two controllers at least on the
LX2160A. In that case, the driver for one controller might misbehave and
consume the other's interrupt. Fix this by actually checking if any of
the bits in the status register have been asserted.
Fixes: 13aed23927 ("spi: spi-fsl-dspi: use IRQF_SHARED mode to request IRQ")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190822211514.19288-3-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
If the entire function depends on the SPI status register having the
interrupt bits asserted, then just check it and exit early if those bits
aren't set (such as in the case of the shared IRQ being triggered for
the other peripheral). Cosmetic patch.
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190822211514.19288-2-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
The DSPI interrupt can be shared between two controllers at least on the
LX2160A. In that case, the driver for one controller might misbehave and
consume the other's interrupt. Fix this by actually checking if any of
the bits in the status register have been asserted.
Fixes: 13aed23927 ("spi: spi-fsl-dspi: use IRQF_SHARED mode to request IRQ")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190822212450.21420-2-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
These are macros that accept 0 or 1 as argument (a boolean value). Their
use encourages the abuse of complex ternary operations inside their
argument list, which detracts from the code readability. Replace these
with simple if-else statements.
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20190818180115.31114-6-olteanv@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Rename this function to of_spi_get_gpio_numbers() as this
is what the function does, it does not register a master,
it is called in the path of registering a master so the
name is logical in a convoluted way, but it is better to
follow Rusty Russell's ABI level no 7:
"The obvious use is (probably) the correct one"
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20190808150321.23319-1-linus.walleij@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Pull spi fixes from Mark Brown:
"A bunch of small, device specific things here plus a DT bindings fix
for the new validatable YAML binding format.
The most notable thing is the fix for GPIO chip selects which fixes a
corner case in updates of that code to modern APIs, unfortunately due
to a historical mess the code around GPIO support is obscure, fragile
and an ABI which makes and attempt to improve the situation painful"
* tag 'spi-fix-v5.3-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi:
spi: pxa2xx: Add support for Intel Tiger Lake
spi: bcm2835: Fix 3-wire mode if DMA is enabled
spi: pxa2xx: Balance runtime PM enable/disable on error
spi: gpio: Add SPI_MASTER_GPIO_SS flag
spi: spi-fsl-qspi: change i.MX7D RX FIFO size
spi: dt-bindings: spi-controller: remove unnecessary 'maxItems: 1' from reg
We don't need dev_err() messages when platform_get_irq() fails now that
platform_get_irq() prints an error message itself when something goes
wrong. Let's remove these prints with a simple semantic patch.
// <smpl>
@@
expression ret;
struct platform_device *E;
@@
ret =
(
platform_get_irq(E, ...)
|
platform_get_irq_byname(E, ...)
);
if ( \( ret < 0 \| ret <= 0 \) )
{
(
-if (ret != -EPROBE_DEFER)
-{ ...
-dev_err(...);
-... }
|
...
-dev_err(...);
)
...
}
// </smpl>
While we're here, remove braces on if statements that only have one
statement (manually).
Cc: Mark Brown <broonie@kernel.org>
Cc: linux-spi@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20190730181557.90391-42-swboyd@chromium.org
Signed-off-by: Mark Brown <broonie@kernel.org>
While there's one file there with briefily describes the uAPI,
the documentation was written just like most subsystems: focused
on kernel developers. So, add it together with driver-api books.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # for iio
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Now Spreadtrum ADI controller supplies multiple master accessing channel
to support multiple subsystems accessing, instead of using a hardware
spinlock to synchronize between the multiple subsystems.
To keep backward compatibility, we should change the hardware spinlock
to be optional. Moreover change to use of_hwspin_lock_get_id() function
which return -ENOENT error number to indicate no hwlock support.
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Link: https://lore.kernel.org/r/2abe7dcf210e4197f8c5ece7fc6d6cc1eda8c655.1564125131.git.baolin.wang@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>
When the system was rebooted by watchdog, now we did not save the watchdog
reset mode which will make system enter a incorrect mode after rebooting.
Thus we should set the watchdog reset mode as default when opening the
watchdog configuration, that means if the system was rebooted by other
reason through the restart_handler(), then we will clear the default
watchdog reset mode to save the correct reset mode.
Signed-off-by: Sherry Zong <sherry.zong@unisoc.com>
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Link: https://lore.kernel.org/r/1563f3de43c6c2262d597a25d6138b5de61ea23d.1564125131.git.baolin.wang@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Commit 6935224da2 ("spi: bcm2835: enable support of 3-wire mode")
added 3-wire support to the BCM2835 SPI driver by setting the REN bit
(Read Enable) in the CS register when receiving data. The REN bit puts
the transmitter in high-impedance state. The driver recognizes that
data is to be received by checking whether the rx_buf of a transfer is
non-NULL.
Commit 3ecd37edaa ("spi: bcm2835: enable dma modes for transfers
meeting certain conditions") subsequently broke 3-wire support because
it set the SPI_MASTER_MUST_RX flag which causes spi_map_msg() to replace
rx_buf with a dummy buffer if it is NULL. As a result, rx_buf is
*always* non-NULL if DMA is enabled.
Reinstate 3-wire support by not only checking whether rx_buf is non-NULL,
but also checking that it is not the dummy buffer.
Fixes: 3ecd37edaa ("spi: bcm2835: enable dma modes for transfers meeting certain conditions")
Reported-by: Nuno Sá <nuno.sa@analog.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: stable@vger.kernel.org # v4.2+
Cc: Martin Sperl <kernel@martin.sperl.org>
Acked-by: Stefan Wahren <wahrenst@gmx.net>
Link: https://lore.kernel.org/r/328318841455e505370ef8ecad97b646c033dc8a.1562148527.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@kernel.org>
