kernel/linux.git/include/linux/serial_core.h, branch linux-6.9.y

serial: core: introduce uart_port_tx_limited_flags()

2024-07-05T07:38:11+00:00

commit 9bb43b9e8d9a288a214e9b17acc9e46fda3977cf upstream. 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"

2024-07-05T07:38:10+00:00

commit c5603e2a621dac10c5e21cc430848ebcfa6c7e01 upstream. 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

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

serial: core: Move struct uart_port::quirks closer to possible values

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

Currently it's not crystal clear what UPIO_* and UPQ_* definitions belong to. Reindent the code, so it will be easy to read and understand. No functional changes intended. Reviewed-by: Andi Shyti Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20240304123035.758700-2-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman

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

2024-03-05T13:37:29+00:00

If the circular buffer is empty, it just means we fit all characters to send into the HW fifo, but not that the hardware finished transmitting them. So if we immediately call stop_tx() after that, this may abort any pending characters in the HW fifo, and cause dropped characters on the console. Fix this by only stopping tx when the tx HW fifo is actually empty. Fixes: 8275b48b2780 ("tty: serial: introduce transmit helpers") Cc: stable@vger.kernel.org Signed-off-by: Jonas Gorski Link: https://lore.kernel.org/r/20240303150807.68117-1-jonas.gorski@gmail.com Signed-off-by: Greg Kroah-Hartman

serial: core: introduce uart_port_tx_flags()

2024-02-06T14:42:02+00:00

And an enum with a flag: UART_TX_NOSTOP. To NOT call __port->ops->stop_tx() when the circular buffer is empty. mxs-uart needs this (see the next patch). Signed-off-by: "Jiri Slaby (SUSE)" Cc: stable Tested-by: Emil Kronborg Link: https://lore.kernel.org/r/20240201105557.28043-1-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman

serial: core: Update uart_poll_timeout() function to return unsigned long

2024-01-04T15:20:05+00:00

The function uart_fifo_timeout() returns an unsigned long value, which is the number of jiffies. Therefore, change the variable timeout in the function uart_poll_timeout() from int to unsigned long. Change the return type of the function uart_poll_timeout() from int to unsigned long to be consistent with the type of timeout values. Signed-off-by: Vamshi Gajjela Link: https://lore.kernel.org/r/20231109063417.3971005-2-vamshigajjela@google.com Signed-off-by: Greg Kroah-Hartman

serial: core: fix kernel-doc for uart_port_unlock_irqrestore()

2023-10-03T12:35:53+00:00

Fix the function name to avoid a kernel-doc warning: include/linux/serial_core.h:666: warning: expecting prototype for uart_port_lock_irqrestore(). Prototype was for uart_port_unlock_irqrestore() instead Fixes: b0af4bcb4946 ("serial: core: Provide port lock wrappers") Signed-off-by: Randy Dunlap Cc: Thomas Gleixner Cc: John Ogness Cc: linux-serial@vger.kernel.org Cc: Greg Kroah-Hartman Cc: Jiri Slaby Reviewed-by: John Ogness Link: https://lore.kernel.org/r/20230927044128.4748-1-rdunlap@infradead.org Signed-off-by: Greg Kroah-Hartman

serial: core: Use lock wrappers

2023-09-18T09:18:08+00:00

When a serial port is used for kernel console output, then all modifications to the UART registers which are done from other contexts, e.g. getty, termios, are interference points for the kernel console. So far this has been ignored and the printk output is based on the principle of hope. The rework of the console infrastructure which aims to support threaded and atomic consoles, requires to mark sections which modify the UART registers as unsafe. This allows the atomic write function to make informed decisions and eventually to restore operational state. It also allows to prevent the regular UART code from modifying UART registers while printk output is in progress. All modifications of UART registers are guarded by the UART port lock, which provides an obvious synchronization point with the console infrastructure. To avoid adding this functionality to all UART drivers, wrap the spin_[un]lock*() invocations for uart_port::lock into helper functions which just contain the spin_[un]lock*() invocations for now. In a subsequent step these helpers will gain the console synchronization mechanisms. Converted with coccinelle. No functional change. Signed-off-by: Thomas Gleixner Reviewed-by: Ilpo Järvinen Signed-off-by: John Ogness Link: https://lore.kernel.org/r/20230914183831.587273-3-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman