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: 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>

net: ks8851: switch to using gpiod API

This patch switches the driver away from legacy gpio/of_gpio API to
gpiod API, and removes use of of_get_named_gpio_flags() which I want to
make private to gpiolib.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20220906204922.3789922-2-dmitry.torokhov@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

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: Register MDIO bus and the internal PHY

The KS8851 has a reduced internal PHY, which is accessible through its
registers at offset 0xe4. The PHY is compatible with KS886x PHY present
in Micrel switches, except the PHY ID Low/High registers are swapped.
Register MDIO bus so this PHY can be detected and probed by phylib.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Heiner Kallweit <hkallweit1@gmail.com>
Cc: Lukas Wunner <lukas@wunner.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

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>

net: ks8851: Use 16-bit writes to program MAC address

On the SPI variant of KS8851, the MAC address can be programmed with
either 8/16/32-bit writes. To make it easier to support the 16-bit
parallel option of KS8851 too, switch both the MAC address programming
and readout to 16-bit operations.

Remove ks8851_wrreg8() as it is not used anywhere anymore.

There should be no functional change.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
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>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

Based on 2 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

net: ks8851: Deduplicate register macros

The ks8851 chip is sold either with an SPI interface (KSZ8851SNL) or
with a so-called non-PCI interface (KSZ8851-16MLL). When the driver
for the latter was introduced with commit a55c0a0ed415 ("drivers/net:
ks8851_mll ethernet network driver"), it duplicated the register macros
introduced by the driver for the former with commit 3ba81f3ece3c ("net:
Micrel KS8851 SPI network driver").

The chips are almost identical, so the duplication seems unwarranted.
There are a handful of bits which are in use on the KSZ8851-16MLL but
reserved on the KSZ8851SNL, and vice-versa, but there are no actual
collisions.

Thus, remove the duplicate definitions from the KSZ8851-16MLL driver.
Mark all bits which differ between the two chips. Move the SPI frame
opcodes, which are specific to KSZ8851SNL, to its driver.

The KSZ8851-16MLL driver added a RXFCTR_THRESHOLD_MASK macro which is a
duplication of the RXFCTR_RXFCT_MASK macro, rename it where it's used.
Same for P1MBCR_FORCE_FDX, which duplicates the BMCR_FULLDPLX macro and
OBCR_ODS_16MA, which duplicates OBCR_ODS_16mA.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Frank Pavlic <f.pavlic@kunbus.de>
Cc: Ben Dooks <ben.dooks@codethink.co.uk>
Cc: Tristram Ha <Tristram.Ha@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ks8851: Fix register macro misnomers

In the header file accompanying the ks8851 driver, the P1SCLMD register
macros are misnamed, they actually pertain to the P1CR register.

The P1CR macros in turn pertain to the P1SR register, see pages 65 to 68
of the spec:
http://www.hqchip.com/uploads/pdf/201703/47c98946d6c97a4766e14db3f24955f2.pdf

The misnomers have no negative consequences so far because the macros
aren't used by ks8851.c, but that's about to change.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Frank Pavlic <f.pavlic@kunbus.de>
Cc: Ben Dooks <ben.dooks@codethink.co.uk>
Cc: Tristram Ha <Tristram.Ha@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net: fix up stale paths from driver reorg

The reorganization of the driver layout in drivers/net
left behind some stale paths in comments and in Kconfig
help text. Bring them up to date. No actual change to
any code takes place here.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
CC: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

KSZ8851-SNL: Add ethtool support for EEPROM via eeprom_93cx6

Add ethtool EEPROM read/write support using the eeprom_93cx6
library instead of open-coding the functions.

Depends on eeprom_93cx6 driver getting EEPROM write support.

Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Signed-off-by: Simtec Linux Team <linux@simtec.co.uk>
[sboyd@codeaurora.org: Removed previous eeprom implementation]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

KSZ8851-SNL: Fix MAC address change problem

When device is off it is under power saving mode. Changing the MAC address
in that situation will result in the device not communicating as the first
write to the MAC address register is not executed.

Signed-off-by: Tristram Ha <Tristram.Ha@micrel.com>
[ben@simtec.co.uk: cleaned up header]
Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

ks8*/ksz8*: Move the Micrel drivers

Move the Micrel drivers into drivers/net/ethernet/micrel/ and
make the necessary Kconfig and Makefile changes.

CC: Ben Dooks <ben@simtec.co.uk>
CC: Tristram Ha <Tristram.Ha@micrel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>