linux-toradex.git/include/linux/serial_core.h, branch v6.16-rc6

serial: switch uart_port::iotype to enum uart_iotype

2025-04-25T11:46:31+00:00

The inline-defined constants look weird. Instead, define a proper enum
for them and type uart_port::iotype as that enum. This allows for proper
checking in switch-case labels (somewhere, a default or UPIO_UNKNOWN
label needs to be added/handled).

Signed-off-by: Jiri Slaby (SUSE) 
Link: https://lore.kernel.org/r/20250425111315.1036184-4-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman

tty: serial: handle HAS_IOPORT dependencies

2024-10-28T21:44:28+00:00

In a future patch HAS_IOPORT=n will disable inb()/outb() and friends at
compile time. We thus need to add HAS_IOPORT as dependency for those
drivers using them unconditionally. Some 8250 serial drivers support
MMIO only use, so fence only the parts requiring I/O ports and print an
error message if a device can't be supported with the current
configuration.

Co-developed-by: Arnd Bergmann 
Signed-off-by: Arnd Bergmann 
Acked-by: Greg Kroah-Hartman 
Reviewed-by: Maciej W. Rozycki 
Signed-off-by: Niklas Schnelle 
Signed-off-by: Arnd Bergmann

serial: core: Acquire nbcon context in port->lock wrapper

2024-08-21T12:56:23+00:00

Currently the port->lock wrappers uart_port_lock(),
uart_port_unlock() (and their variants) only lock/unlock
the spin_lock.

If the port is an nbcon console that has implemented the
write_atomic() callback, the wrappers must also acquire/release
the console context and mark the region as unsafe. This allows
general port->lock synchronization to be synchronized against
the nbcon write_atomic() callback.

Note that __uart_port_using_nbcon() relies on the port->lock
being held while a console is added and removed from the
console list (i.e. all uart nbcon drivers *must* take the
port->lock in their device_lock() callbacks).

Signed-off-by: John Ogness 
Acked-by: Greg Kroah-Hartman 
Reviewed-by: Petr Mladek 
Link: https://lore.kernel.org/r/20240820063001.36405-15-john.ogness@linutronix.de
Signed-off-by: Petr Mladek

serial: core: Introduce wrapper to set @uart_port->cons

2024-08-21T12:56:23+00:00

Introduce uart_port_set_cons() as a wrapper to set @cons of a
uart_port. The wrapper sets @cons under the port lock in order
to prevent @cons from disappearing while another context is
holding the port lock. This is necessary for a follow-up
commit relating to the port lock wrappers, which rely on @cons
not changing between lock and unlock.

Signed-off-by: John Ogness 
Tested-by: Théo Lebrun  # EyeQ5, AMBA-PL011
Acked-by: Greg Kroah-Hartman 
Reviewed-by: Petr Mladek 
Reviewed-by: Ilpo Järvinen 
Link: https://lore.kernel.org/r/20240820063001.36405-12-john.ogness@linutronix.de
Signed-off-by: Petr Mladek

serial: core: Provide low-level functions to lock port

2024-08-21T12:56:23+00:00

It will be necessary at times for the uart nbcon console
drivers to acquire the port lock directly (without the
additional nbcon functionality of the port lock wrappers).
These are special cases such as the implementation of the
device_lock()/device_unlock() callbacks or for internal
port lock wrapper synchronization.

Provide low-level variants __uart_port_lock_irqsave() and
__uart_port_unlock_irqrestore() for this purpose.

Signed-off-by: John Ogness 
Reviewed-by: Petr Mladek 
Acked-by: Greg Kroah-Hartman 
Link: https://lore.kernel.org/r/20240820063001.36405-11-john.ogness@linutronix.de
Signed-off-by: Petr Mladek

serial: core: introduce uart_port_tx_limited_flags()

2024-06-24T14:14:48+00:00

Analogue to uart_port_tx_flags() introduced in commit 3ee07964d407
("serial: core: introduce uart_port_tx_flags()"), add a _flags variant
for uart_port_tx_limited().

Fixes: d11cc8c3c4b6 ("tty: serial: use uart_port_tx_limited()")
Cc: stable@vger.kernel.org
Signed-off-by: Jonas Gorski 
Signed-off-by: Doug Brown 
Link: https://lore.kernel.org/r/20240606195632.173255-3-doug@schmorgal.com
Signed-off-by: Greg Kroah-Hartman

Revert "serial: core: only stop transmit when HW fifo is empty"

2024-06-24T14:14:33+00:00

This reverts commit 7bfb915a597a301abb892f620fe5c283a9fdbd77.

This commit broke pxa and omap-serial, because it inhibited them from
calling stop_tx() if their TX FIFOs weren't completely empty. This
resulted in these two drivers hanging during transmits because the TX
interrupt would stay enabled, and a new TX interrupt would never fire.

Cc: stable@vger.kernel.org
Fixes: 7bfb915a597a ("serial: core: only stop transmit when HW fifo is empty")
Signed-off-by: Doug Brown 
Link: https://lore.kernel.org/r/20240606195632.173255-2-doug@schmorgal.com
Signed-off-by: Greg Kroah-Hartman

tty: serial: switch from circ_buf to kfifo

2024-04-09T13:28:03+00:00

Switch from struct circ_buf to proper kfifo. kfifo provides much better
API, esp. when wrap-around of the buffer needs to be taken into account.
Look at pl011_dma_tx_refill() or cpm_uart_tx_pump() changes for example.

Kfifo API can also fill in scatter-gather DMA structures, so it easier
for that use case too. Look at lpuart_dma_tx() for example. Note that
not all drivers can be converted to that (like atmel_serial), they
handle DMA specially.

Note that usb-serial uses kfifo for TX for ages.

omap needed a bit more care as it needs to put a char into FIFO to start
the DMA transfer when OMAP_DMA_TX_KICK is set. In that case, we have to
do kfifo_dma_out_prepare twice: once to find out the tx_size (to find
out if it is worths to do DMA at all -- size >= 4), the second time for
the actual transfer.

All traces of circ_buf are removed from serial_core.h (and its struct
uart_state).

Signed-off-by: Jiri Slaby (SUSE) 
Cc: Al Cooper 
Cc: Matthias Brugger 
Cc: AngeloGioacchino Del Regno 
Cc: Kumaravel Thiagarajan 
Cc: Tharun Kumar P 
Cc: Russell King 
Cc: Vineet Gupta 
Cc: Richard Genoud 
Cc: Nicolas Ferre 
Cc: Alexandre Belloni 
Cc: Claudiu Beznea 
Cc: Alexander Shiyan 
Cc: Baruch Siach 
Cc: Maciej W. Rozycki 
Cc: Shawn Guo 
Cc: Sascha Hauer 
Cc: Fabio Estevam 
Cc: Neil Armstrong 
Cc: Kevin Hilman 
Cc: Jerome Brunet 
Cc: Martin Blumenstingl 
Cc: Taichi Sugaya 
Cc: Takao Orito 
Cc: Bjorn Andersson 
Cc: Konrad Dybcio 
Cc: Pali Rohár 
Cc: Michael Ellerman 
Cc: Nicholas Piggin 
Cc: Christophe Leroy 
Cc: Aneesh Kumar K.V 
Cc: Naveen N. Rao 
Cc: Manivannan Sadhasivam 
Cc: Krzysztof Kozlowski 
Cc: Alim Akhtar 
Cc: Laxman Dewangan 
Cc: Thierry Reding 
Cc: Jonathan Hunter 
Cc: Orson Zhai 
Cc: Baolin Wang 
Cc: Chunyan Zhang 
Cc: Patrice Chotard 
Cc: Maxime Coquelin 
Cc: Alexandre Torgue 
Cc: David S. Miller 
Cc: Hammer Hsieh 
Cc: Peter Korsgaard 
Cc: Timur Tabi 
Cc: Michal Simek 
Cc: Sumit Semwal 
Cc: Christian König 
Link: https://lore.kernel.org/r/20240405060826.2521-13-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman

serial: port: Introduce a common helper to read properties

2024-03-05T13:38:28+00:00

Several serial drivers want to read the same or similar set of
the port properties. Make a common helper for them.

Signed-off-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20240304123035.758700-4-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman

serial: core: Add UPIO_UNKNOWN constant for unknown port type

2024-03-05T13:38:28+00:00

In some APIs we would like to assign the special value to iotype
and compare against it in another places. Introduce UPIO_UNKNOWN
for this purpose.

Note, we can't use 0, because it's a valid value for IO port access.

Signed-off-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20240304123035.758700-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman