net: ks8851: Inline ks8851_rx_skb()

Both ks8851_rx_skb_par() and ks8851_rx_skb_spi() call netif_rx(skb),
inline the netif_rx(skb) call directly into ks8851_common.c and drop
the .rx_skb callback and ks8851_rx_skb() wrapper. This removes one
indirect call from the driver, no functional change otherwise.

Signed-off-by: Marek Vasut <marex@denx.de>
Link: https://lore.kernel.org/r/20240405203204.82062-1-marex@denx.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: ks8851: Follow renaming of SPI "master" to "controller"

In commit 8caab75fd2c2 ("spi: Generalize SPI "master" to "controller"")
some functions and struct members were renamed. To not break all drivers
compatibility macros were provided.

To be able to remove these compatibility macros push the renaming into
this driver.

Reviewed-by: Simon Horman <horms@kernel.org>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/4f26761c0c86072a084b2a20439da1d0a681b07b.1707324794.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>

treewide, spi: Get rid of SPI_MASTER_HALF_DUPLEX

The SPI_MASTER_HALF_DUPLEX is the legacy name of a definition
for a half duplex flag. Since all others had been replaced with
the respective SPI_CONTROLLER prefix get rid of the last one
as well. There is no functional change intended.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # For MMC
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> # for input
Acked-by: Paolo Abeni <pabeni@redhat.com>
Link: https://lore.kernel.org/r/20231113111249.3982461-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

net: ks8851: Fix TX stall caused by TX buffer overrun

There is a bug in the ks8851 Ethernet driver that more data is written
to the hardware TX buffer than actually available. This is caused by
wrong accounting of the free TX buffer space.

The driver maintains a tx_space variable that represents the TX buffer
space that is deemed to be free. The ks8851_start_xmit_spi() function
adds an SKB to a queue if tx_space is large enough and reduces tx_space
by the amount of buffer space it will later need in the TX buffer and
then schedules a work item. If there is not enough space then the TX
queue is stopped.

The worker function ks8851_tx_work() dequeues all the SKBs and writes
the data into the hardware TX buffer. The last packet will trigger an
interrupt after it was send. Here it is assumed that all data fits into
the TX buffer.

In the interrupt routine (which runs asynchronously because it is a
threaded interrupt) tx_space is updated with the current value from the
hardware. Also the TX queue is woken up again.

Now it could happen that after data was sent to the hardware and before
handling the TX interrupt new data is queued in ks8851_start_xmit_spi()
when the TX buffer space had still some space left. When the interrupt
is actually handled tx_space is updated from the hardware but now we
already have new SKBs queued that have not been written to the hardware
TX buffer yet. Since tx_space has been overwritten by the value from the
hardware the space is not accounted for.

Now we have more data queued then buffer space available in the hardware
and ks8851_tx_work() will potentially overrun the hardware TX buffer. In
many cases it will still work because often the buffer is written out
fast enough so that no overrun occurs but for example if the peer
throttles us via flow control then an overrun may happen.

This can be fixed in different ways. The most simple way would be to set
tx_space to 0 before writing data to the hardware TX buffer preventing
the queuing of more SKBs until the TX interrupt has been handled. I have
chosen a slightly more efficient (and still rather simple) way and
track the amount of data that is already queued and not yet written to
the hardware. When new SKBs are to be queued the already queued amount
of data is honoured when checking free TX buffer space.

I tested this with a setup of two linked KS8851 running iperf3 between
the two in bidirectional mode. Before the fix I got a stall after some
minutes. With the fix I saw now issues anymore after hours.

Fixes: 3ba81f3ece3c ("net: Micrel KS8851 SPI network driver")
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Ben Dooks <ben.dooks@codethink.co.uk>
Cc: Tristram Ha <Tristram.Ha@microchip.com>
Cc: netdev@vger.kernel.org
Cc: stable@vger.kernel.org # 5.10+
Signed-off-by: Ronald Wahl <ronald.wahl@raritan.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20231214181112.76052-1-rwahl@gmx.de
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

micrel: ksz8851: fixes struct pointer issue

Issue found during code review. This bug has no impact as long as the
ks8851_net structure is the first element of the ks8851_net_spi structure.
As long as the offset to the ks8851_net struct is zero, the container_of()
macro is subtracting 0 and therefore no damage done. But if the
ks8851_net_spi struct is ever modified such that the ks8851_net struct
within it is no longer the first element of the struct, then the bug would
manifest itself and cause problems.

struct ks8851_net is contained within ks8851_net_spi.
ks is contained within kss.
kss is the priv_data of the netdev structure.

Signed-off-by: Jerry Ray <jerry.ray@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ethernet: Use netif_rx().

Since commit
baebdf48c3600 ("net: dev: Makes sure netif_rx() can be invoked in any context.")

the function netif_rx() can be used in preemptible/thread context as
well as in interrupt context.

Use netif_rx().

Cc: Łukasz Stelmach <l.stelmach@samsung.com>
Cc: Horatiu Vultur <horatiu.vultur@microchip.com>
Cc: UNGLinuxDriver@microchip.com
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

spi: make remove callback a void function

The value returned by an spi driver's remove function is mostly ignored.
(Only an error message is printed if the value is non-zero that the
error is ignored.)

So change the prototype of the remove function to return no value. This
way driver authors are not tempted to assume that passing an error to
the upper layer is a good idea. All drivers are adapted accordingly.
There is no intended change of behaviour, all callbacks were prepared to
return 0 before.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Claudius Heine <ch@denx.de>
Acked-by: Stefan Schmidt <stefan@datenfreihafen.org>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # For MMC
Acked-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Acked-by: Łukasz Stelmach <l.stelmach@samsung.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20220123175201.34839-6-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>

net: ks8851: Make ks8851_remove_common() return void

Up to now ks8851_remove_common() returns zero unconditionally. Make it
return void instead which makes it easier to see in the callers that
there is no error to handle.

Also the return value of platform and spi remove callbacks is ignored
anyway.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ks8851: remove definition of DEBUG

Defining DEBUG should only be done in development.
So remove DEBUG.

Signed-off-by: Tom Rix <trix@redhat.com>
Reviewed-by: Marek Vasut <marex@denx.de>
Link: https://lore.kernel.org/r/20210115153128.131026-1-trix@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: ks8851: Separate SPI operations into separate file

Pull all the SPI bus specific code into a separate file, so that it is
not mixed with the common code. Rename ks8851.c to ks8851_common.c. The
ks8851_common.c is linked with ks8851_spi.c now, so it can call the
accessors in the ks8851_spi.c without any pointer indirection.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Lukas Wunner <lukas@wunner.de>
Cc: Petr Stetiar <ynezz@true.cz>
Cc: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>