treewide, serdev: change receive_buf() return type to size_t

receive_buf() is called from ttyport_receive_buf() that expects values
">= 0" from serdev_controller_receive_buf(), change its return type from
ssize_t to size_t.

The need for this clean-up was noticed while fixing a warning, see
commit 94d053942544 ("Bluetooth: btnxpuart: fix recv_buf() return value").
Changing the callback prototype to return an unsigned seems the best way
to document the API and ensure that is properly used.

GNSS drivers implementation of serdev receive_buf() callback return
directly the return value of gnss_insert_raw(). gnss_insert_raw()
returns a signed int, however this is not an issue since the value
returned is always positive, because of the kfifo_in() implementation.
gnss_insert_raw() could be changed to return also an unsigned, however
this is not implemented here as request by the GNSS maintainer Johan
Hovold.

Suggested-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/all/087be419-ec6b-47ad-851a-5e1e3ea5cfcc@kernel.org/
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> #for-iio
Reviewed-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Alex Elder <elder@linaro.org>
Acked-by: Maximilian Luz <luzmaximilian@gmail.com> # for platform/surface
Acked-by: Lee Jones <lee@kernel.org>
Acked-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20240122180551.34429-1-francesco@dolcini.it
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serdev: convert to u8 and size_t

Switch character types to u8 and sizes to size_t. To conform to
characters/sizes in the rest of the tty layer.

This patch converts struct serdev_device_ops hooks and its
instantiations.

Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Acked-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20231206073712.17776-24-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

treewide: Convert del_timer*() to timer_shutdown*()

Due to several bugs caused by timers being re-armed after they are
shutdown and just before they are freed, a new state of timers was added
called "shutdown". After a timer is set to this state, then it can no
longer be re-armed.

The following script was run to find all the trivial locations where
del_timer() or del_timer_sync() is called in the same function that the
object holding the timer is freed. It also ignores any locations where
the timer->function is modified between the del_timer*() and the free(),
as that is not considered a "trivial" case.

This was created by using a coccinelle script and the following
commands:

$ cat timer.cocci
@@
expression ptr, slab;
identifier timer, rfield;
@@
(
- del_timer(&ptr->timer);
+ timer_shutdown(&ptr->timer);
|
- del_timer_sync(&ptr->timer);
+ timer_shutdown_sync(&ptr->timer);
)
... when strict
when != ptr->timer
(
kfree_rcu(ptr, rfield);
|
kmem_cache_free(slab, ptr);
|
kfree(ptr);
)

$ spatch timer.cocci . > /tmp/t.patch
$ patch -p1 < /tmp/t.patch

Link: https://lore.kernel.org/lkml/20221123201306.823305113@linutronix.de/
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Pavel Machek <pavel@ucw.cz> [ LED ]
Acked-by: Kalle Valo <kvalo@kernel.org> [ wireless ]
Acked-by: Paolo Abeni <pabeni@redhat.com> [ networking ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nfc: pn533: Fix use-after-free bugs caused by pn532_cmd_timeout

When the pn532 uart device is detaching, the pn532_uart_remove()
is called. But there are no functions in pn532_uart_remove() that
could delete the cmd_timeout timer, which will cause use-after-free
bugs. The process is shown below:

(thread 1) | (thread 2)
| pn532_uart_send_frame
pn532_uart_remove | mod_timer(&pn532->cmd_timeout,...)
... | (wait a time)
kfree(pn532) //FREE | pn532_cmd_timeout
| pn532_uart_send_frame
| pn532->... //USE

This patch adds del_timer_sync() in pn532_uart_remove() in order to
prevent the use-after-free bugs. What's more, the pn53x_unregister_nfc()
is well synchronized, it sets nfc_dev->shutting_down to true and there
are no syscalls could restart the cmd_timeout timer.

Fixes: c656aa4c27b1 ("nfc: pn533: add UART phy driver")
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfc: pn533: Constify pn533_phy_ops

Neither the driver or the core modifies the pn533_phy_ops struct, so
make them const to allow the compiler to put the static structs in
read-only memory.

Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfc: pn533: Constify serdev_device_ops

The only usage of pn532_serdev_ops is to pass its address to
serdev_device_set_client_ops(), which takes a pointer to const
serdev_device_ops as argument. Make it const to allow the compiler to
put it in read-only memory.

Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfc: pn533: drop of_match_ptr from device ID table

The driver can match only via the DT table so the table should be always
used and the of_match_ptr does not have any sense (this also allows ACPI
matching via PRP0001, even though it might be not relevant here). This
fixes compile warning (!CONFIG_OF):

drivers/nfc/pn533/i2c.c:252:34: warning:
‘of_pn533_i2c_match’ defined but not used [-Wunused-const-variable=]

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Link: https://lore.kernel.org/r/20210528124200.79655-4-krzysztof.kozlowski@canonical.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

nfc: pn533: pn533_phy_ops dev_[up, down] return int

Change dev_up and dev_down functions of struct pn533_phy_ops to return
int. This way the pn533 core can report errors in the phy layer to upper
layers.
The only user of this is currently uart.c and it is changed to report
the error of a possibly failing call to serdev_device_open.

Reported-by: coverity-bot <keescook+coverity-bot@chromium.org>
Addresses-Coverity-ID: 1487395 ("Error handling issues")
Fixes: c656aa4c27b1 ("nfc: pn533: add UART phy driver")
Signed-off-by: Lars Poeschel <poeschel@lemonage.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfc: pn532_uart: Make use of pn532 autopoll

This switches the pn532 UART phy driver from manually polling to the new
autopoll mechanism.

Cc: Johan Hovold <johan@kernel.org>
Signed-off-by: Lars Poeschel <poeschel@lemonage.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfc: pn533: add UART phy driver

This adds the UART phy interface for the pn533 driver.
The pn533 driver can be used through UART interface this way.
It is implemented as a serdev device.

Cc: Johan Hovold <johan@kernel.org>
Cc: Claudiu Beznea <Claudiu.Beznea@microchip.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Lars Poeschel <poeschel@lemonage.de>
Signed-off-by: David S. Miller <davem@davemloft.net>