platform/mellanox: mlxbf-tmfifo: Drop Tx network packet when Tx TmFIFO is full

Starting from Linux 5.16 kernel, Tx timeout mechanism was added
in the virtio_net driver which prints the "Tx timeout" warning
message when a packet stays in Tx queue for too long. Below is an
example of the reported message:

"[494105.316739] virtio_net virtio1 tmfifo_net0: TX timeout on
queue: 0, sq: output.0, vq: 0×1, name: output.0, usecs since
last trans: 3079892256".

This issue could happen when external host driver which drains the
FIFO is restared, stopped or upgraded. To avoid such confusing
"Tx timeout" messages, this commit adds logic to drop the outstanding
Tx packet if it's not able to transmit in two seconds due to Tx FIFO
full, which can be considered as congestion or out-of-resource drop.

This commit also handles the special case that the packet is half-
transmitted into the Tx FIFO. In such case, the packet is discarded
with remaining length stored in vring->rem_padding. So paddings with
zeros can be sent out when Tx space is available to maintain the
integrity of the packet format. The padded packet will be dropped on
the receiving side.

Signed-off-by: Liming Sun <limings@nvidia.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20240111173106.96958-1-limings@nvidia.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

platform/mellanox: mlxbf-tmfifo: Remove unnecessary bool conversion

This commit fixes coccinelle warning in macro function
IS_VRING_DROP() which complains conversion to bool not needed here.

Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Link: https://lore.kernel.org/r/ZUWIIKbz4vukl8qb@octinomon
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

platform/mellanox: mlxbf-tmfifo: Convert to platform remove callback returning void

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.

To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new(), which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20230927081040.2198742-16-u.kleine-koenig@pengutronix.de
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

platform/mellanox: mlxbf-tmfifo: Fix a warning message

This commit fixes the smatch static checker warning in function
mlxbf_tmfifo_rxtx_word() which complains data not initialized at
line 634 when IS_VRING_DROP() is TRUE.

Signed-off-by: Liming Sun <limings@nvidia.com>
Link: https://lore.kernel.org/r/20231012230235.219861-1-limings@nvidia.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

platform/mellanox: tmfifo: fix kernel-doc warnings

Fix kernel-doc notation for structs and struct members to prevent
these warnings:

mlxbf-tmfifo.c:73: warning: cannot understand function prototype: 'struct mlxbf_tmfifo_vring '
mlxbf-tmfifo.c:128: warning: cannot understand function prototype: 'struct mlxbf_tmfifo_vdev '
mlxbf-tmfifo.c:146: warning: cannot understand function prototype: 'struct mlxbf_tmfifo_irq_info '
mlxbf-tmfifo.c:158: warning: cannot understand function prototype: 'struct mlxbf_tmfifo_io '
mlxbf-tmfifo.c:182: warning: cannot understand function prototype: 'struct mlxbf_tmfifo '
mlxbf-tmfifo.c:208: warning: cannot understand function prototype: 'struct mlxbf_tmfifo_msg_hdr '
mlxbf-tmfifo.c:138: warning: Function parameter or member 'config' not described in 'mlxbf_tmfifo_vdev'
mlxbf-tmfifo.c:212: warning: Function parameter or member 'unused' not described in 'mlxbf_tmfifo_msg_hdr'

Fixes: 1357dfd7261f ("platform/mellanox: Add TmFifo driver for Mellanox BlueField Soc")
Fixes: bc05ea63b394 ("platform/mellanox: Add BlueField-3 support in the tmfifo driver")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: kernel test robot <lkp@intel.com>
Closes: lore.kernel.org/r/202309252330.saRU491h-lkp@intel.com
Cc: Liming Sun <lsun@mellanox.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Cc: Mark Gross <markgross@kernel.org>
Cc: Vadim Pasternak <vadimp@nvidia.com>
Cc: platform-driver-x86@vger.kernel.org
Link: https://lore.kernel.org/r/20230926054013.11450-1-rdunlap@infradead.org
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

platform/mellanox: mlxbf-tmfifo: Drop jumbo frames

This commit drops over-sized network packets to avoid tmfifo
queue stuck.

Fixes: 1357dfd7261f ("platform/mellanox: Add TmFifo driver for Mellanox BlueField Soc")
Signed-off-by: Liming Sun <limings@nvidia.com>
Reviewed-by: Vadim Pasternak <vadimp@nvidia.com>
Reviewed-by: David Thompson <davthompson@nvidia.com>
Link: https://lore.kernel.org/r/9318936c2447f76db475c985ca6d91f057efcd41.1693322547.git.limings@nvidia.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

platform/mellanox: mlxbf-tmfifo: Drop the Rx packet if no more descriptors

This commit fixes tmfifo console stuck issue when the virtual
networking interface is in down state. In such case, the network
Rx descriptors runs out and causes the Rx network packet staying
in the head of the tmfifo thus blocking the console packets. The
fix is to drop the Rx network packet when no more Rx descriptors.
Function name mlxbf_tmfifo_release_pending_pkt() is also renamed
to mlxbf_tmfifo_release_pkt() to be more approperiate.

Fixes: 1357dfd7261f ("platform/mellanox: Add TmFifo driver for Mellanox BlueField Soc")
Signed-off-by: Liming Sun <limings@nvidia.com>
Reviewed-by: Vadim Pasternak <vadimp@nvidia.com>
Reviewed-by: David Thompson <davthompson@nvidia.com>
Link: https://lore.kernel.org/r/8c0177dc938ae03f52ff7e0b62dbeee74b7bec09.1693322547.git.limings@nvidia.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

platform/mellanox: Fix mlxbf-tmfifo not handling all virtio CONSOLE notifications

rshim console does not show all entries of dmesg.

Fixed by setting MLXBF_TM_TX_LWM_IRQ for every CONSOLE notification.

Signed-off-by: Shih-Yi Chen <shihyic@nvidia.com>
Reviewed-by: Liming Sung <limings@nvidia.com>
Reviewed-by: David Thompson <davthompson@nvidia.com>
Link: https://lore.kernel.org/r/20230821150627.26075-1-shihyic@nvidia.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

platform/mellanox: fix potential race in mlxbf-tmfifo driver

This commit adds memory barrier for the 'vq' update in function
mlxbf_tmfifo_virtio_find_vqs() to avoid potential race due to
out-of-order memory write. It also adds barrier for the 'is_ready'
flag to make sure the initializations are visible before this flag
is checked.

Signed-off-by: Liming Sun <limings@nvidia.com>
Reviewed-by: Vadim Pasternak <vadimp@nvidia.com>
Link: https://lore.kernel.org/r/b98c0ab61d644ba38fa9b3fd1607b138b0dd820b.1682518748.git.limings@nvidia.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

platform/mellanox: Add BlueField-3 support in the tmfifo driver

BlueField-3 uses the same control registers in tmfifo access but
at different addresses. This commit replaces the offset reference
with pointers, and set up these pointers in the probe functions
accordingly.

Signed-off-by: Liming Sun <limings@nvidia.com>
Reviewed-by: David Thompson <davthompson@nvidia.com>
Reviewed-by: Vadim Pasternak <vadimp@nvidia.com>
Link: https://lore.kernel.org/r/20221018133303.243920-1-limings@nvidia.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

virtio: Revert "virtio: find_vqs() add arg sizes"

This reverts commit a10fba0377145fccefea4dc4dd5915b7ed87e546: the
proposed API isn't supported on all transports but no
effort was made to address this.

It might not be hard to fix if we want to: maybe just
rename size to size_hint and make sure legacy
transports ignore the hint.

But it's not sure what the benefit is in any case, so
let's drop it.

Fixes: a10fba037714 ("virtio: find_vqs() add arg sizes")
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20220816053602.173815-8-mst@redhat.com>

virtio: find_vqs() add arg sizes

find_vqs() adds a new parameter sizes to specify the size of each vq
vring.

NULL as sizes means that all queues in find_vqs() use the maximum size.
A value in the array is 0, which means that the corresponding queue uses
the maximum size.

In the split scenario, the meaning of size is the largest size, because
it may be limited by memory, the virtio core will try a smaller size.
And the size is power of 2.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20220801063902.129329-34-xuanzhuo@linux.alibaba.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

virtio: record the maximum queue num supported by the device.

virtio-net can display the maximum (supported by hardware) ring size in
ethtool -g eth0.

When the subsequent patch implements vring reset, it can judge whether
the ring size passed by the driver is legal based on this.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20220801063902.129329-2-xuanzhuo@linux.alibaba.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

platform/mellanox: mlxbf-tmfifo: Fix a memory barrier issue

The virtio framework uses wmb() when updating avail->idx. It
guarantees the write order, but not necessarily loading order
for the code accessing the memory. This commit adds a load barrier
after reading the avail->idx to make sure all the data in the
descriptor is visible. It also adds a barrier when returning the
packet to virtio framework to make sure read/writes are visible to
the virtio code.

Fixes: 1357dfd7261f ("platform/mellanox: Add TmFifo driver for Mellanox BlueField Soc")
Signed-off-by: Liming Sun <limings@nvidia.com>
Reviewed-by: Vadim Pasternak <vadimp@nvidia.com>
Link: https://lore.kernel.org/r/1620433812-17911-1-git-send-email-limings@nvidia.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

mlxbf-tmfifo: sparse tags for config access

mlxbf-tmfifo accesses config space using native types -
which works for it since the legacy virtio native types.

This will break if it ever needs to support modern virtio,
so with new tags previously introduced for virtio net config,
sparse now warns for this in drivers.

Since this is a legacy only device, fix it up using
virtio_legacy_is_little_endian for now.

No functional changes.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com>

platform/mellanox: fix potential deadlock in the tmfifo driver

This commit fixes the potential deadlock caused by the console Rx
and Tx processing at the same time. Rx and Tx both take the console
and tmfifo spinlock but in different order which causes potential
deadlock. The fix is to use different tmfifo spinlock for Rx and
Tx since they protect different resources and it's safe to split
the lock.

Below is the reported call trace when copying/pasting large string
in the console.

Rx:
_raw_spin_lock_irqsave (hvc lock)
__hvc_poll
hvc_poll
in_intr
vring_interrupt
mlxbf_tmfifo_rxtx_one_desc (tmfifo lock)
mlxbf_tmfifo_rxtx
mlxbf_tmfifo_work_rxtx
Tx:
_raw_spin_lock_irqsave (tmfifo lock)
mlxbf_tmfifo_virtio_notify
virtqueue_notify
virtqueue_kick
put_chars
hvc_push
hvc_write (hvc lock)
...
do_tty_write
tty_write

Fixes: 1357dfd7261f ("platform/mellanox: Add TmFifo driver for Mellanox BlueField Soc")
Cc: <stable@vger.kernel.org> # 5.4+
Reviewed-by: David Woods <dwoods@mellanox.com>
Signed-off-by: Liming Sun <lsun@mellanox.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

platform/mellanox: fix potential deadlock in the tmfifo driver

This commit fixes the potential deadlock caused by the console Rx
and Tx processing at the same time. Rx and Tx both take the console
and tmfifo spinlock but in different order which causes potential
deadlock. The fix is to use different tmfifo spinlock for Rx and
Tx since they protect different resources and it's safe to split
the lock.

Below is the reported call trace when copying/pasting large string
in the console.

Rx:
_raw_spin_lock_irqsave (hvc lock)
__hvc_poll
hvc_poll
in_intr
vring_interrupt
mlxbf_tmfifo_rxtx_one_desc (tmfifo lock)
mlxbf_tmfifo_rxtx
mlxbf_tmfifo_work_rxtx
Tx:
_raw_spin_lock_irqsave (tmfifo lock)
mlxbf_tmfifo_virtio_notify
virtqueue_notify
virtqueue_kick
put_chars
hvc_push
hvc_write (hvc lock)
...
do_tty_write
tty_write

Fixes: 1357dfd7261f ("platform/mellanox: Add TmFifo driver for Mellanox BlueField Soc")
Cc: <stable@vger.kernel.org> # 5.4+
Reviewed-by: David Woods <dwoods@mellanox.com>
Signed-off-by: Liming Sun <lsun@mellanox.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

platform/mellanox: Add TmFifo driver for Mellanox BlueField Soc

This commit adds the TmFifo platform driver for Mellanox BlueField
Soc. TmFifo is a shared FIFO which enables external host machine
to exchange data with the SoC via USB or PCIe. The driver is based
on virtio framework and has console and network access enabled.

Reviewed-by: Vadim Pasternak <vadimp@mellanox.com>
Signed-off-by: Liming Sun <lsun@mellanox.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>