user/sven/linux.git/include/linux/serial_core.h, branch v5.4.90

docs: serial: move it to the driver-api

2019-07-15T14:03:03Z

The contents of this directory is mostly driver-api stuff. Signed-off-by: Mauro Carvalho Chehab

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156

2019-05-30T18:26:35Z

Based on 1 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 as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 59 temple place suite 330 boston ma 02111 1307 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1334 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Reviewed-by: Richard Fontana Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de Signed-off-by: Greg Kroah-Hartman

docs: serial: convert docs to ReST and rename to *.rst

2019-04-25T09:37:42Z

The converted files are focused at the Kernel internal API, so, this is a good candidate for the kernel API set of books. The conversion is actually: - add blank lines and identation in order to identify paragraphs; - fix tables markups; - add some lists markups; - mark literal blocks; - adjust title markups. At its new index.rst, let's add a :orphan: while this is not linked to the main index.rst file, in order to avoid build warnings. Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Greg Kroah-Hartman

serial: core: Include console.h from serial_core.h

2018-11-09T17:07:17Z

In the static inline function uart_handle_break() in serial_core.h we dereference port->cons. That gives an error unless console.h is also included. This error hasn't shown up till now because everyone who has defined SUPPORT_SYSRQ has also included console.h, but it's a bit ugly to make this requirement. Let's make the include explicit. Signed-off-by: Douglas Anderson Signed-off-by: Greg Kroah-Hartman

serial: core: Allow processing sysrq at port unlock time

2018-11-09T17:07:17Z

Right now serial drivers process sysrq keys deep in their character receiving code. This means that they've already grabbed their port->lock spinlock. This can end up getting in the way if we've go to do serial stuff (especially kgdb) in response to the sysrq. Serial drivers have various hacks in them to handle this. Looking at '8250_port.c' you can see that the console_write() skips locking if we're in the sysrq handler. Looking at 'msm_serial.c' you can see that the port lock is dropped around uart_handle_sysrq_char(). It turns out that these hacks aren't exactly perfect. If you have lockdep turned on and use something like the 8250_port hack you'll get a splat that looks like: WARNING: possible circular locking dependency detected [...] is trying to acquire lock: ... (console_owner){-.-.}, at: console_unlock+0x2e0/0x5e4 but task is already holding lock: ... (&port_lock_key){-.-.}, at: serial8250_handle_irq+0x30/0xe4 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&port_lock_key){-.-.}: _raw_spin_lock_irqsave+0x58/0x70 serial8250_console_write+0xa8/0x250 univ8250_console_write+0x40/0x4c console_unlock+0x528/0x5e4 register_console+0x2c4/0x3b0 uart_add_one_port+0x350/0x478 serial8250_register_8250_port+0x350/0x3a8 dw8250_probe+0x67c/0x754 platform_drv_probe+0x58/0xa4 really_probe+0x150/0x294 driver_probe_device+0xac/0xe8 __driver_attach+0x98/0xd0 bus_for_each_dev+0x84/0xc8 driver_attach+0x2c/0x34 bus_add_driver+0xf0/0x1ec driver_register+0xb4/0x100 __platform_driver_register+0x60/0x6c dw8250_platform_driver_init+0x20/0x28 ... -> #0 (console_owner){-.-.}: lock_acquire+0x1e8/0x214 console_unlock+0x35c/0x5e4 vprintk_emit+0x230/0x274 vprintk_default+0x7c/0x84 vprintk_func+0x190/0x1bc printk+0x80/0xa0 __handle_sysrq+0x104/0x21c handle_sysrq+0x30/0x3c serial8250_read_char+0x15c/0x18c serial8250_rx_chars+0x34/0x74 serial8250_handle_irq+0x9c/0xe4 dw8250_handle_irq+0x98/0xcc serial8250_interrupt+0x50/0xe8 ... other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&port_lock_key); lock(console_owner); lock(&port_lock_key); lock(console_owner); *** DEADLOCK *** The hack used in 'msm_serial.c' doesn't cause the above splats but it seems a bit ugly to unlock / lock our spinlock deep in our irq handler. It seems like we could defer processing the sysrq until the end of the interrupt handler right after we've unlocked the port. With this scheme if a whole batch of sysrq characters comes in one irq then we won't handle them all, but that seems like it should be a fine compromise. Signed-off-by: Douglas Anderson Signed-off-by: Greg Kroah-Hartman

Revert "serial:serial_core: Allow use of CTS for PPS line discipline"

2018-10-04T16:57:45Z

This reverts commit c550f01c810f2197c98e6e3103f81797f5e063be. Turns out the samsung tty driver is mucking around in the "unused" port fields and this patch breaks that code :( So we need to fix that driver up before this can be accepted. Reported-by: Stephen Rothwell Cc: Steve Sakoman Signed-off-by: Greg Kroah-Hartman

tty/serial_core: add ISO7816 infrastructure

2018-10-02T20:38:55Z

Add the ISO7816 ioctl and associated accessors and data structure. Drivers can then use this common implementation to handle ISO7816 (smart cards). Signed-off-by: Nicolas Ferre [ludovic.desroches@microchip.com: squash and rebase, removal of gpios, checkpatch fixes] Signed-off-by: Ludovic Desroches Signed-off-by: Greg Kroah-Hartman

serial:serial_core: Allow use of CTS for PPS line discipline

2018-10-02T20:38:55Z

Add a "pps_4wire" file to serial ports in sysfs in case the kernel is configured with CONFIG_PPS_CLIENT_LDISC. Writing 1 to the file enables the use of CTS instead of DCD for PPS signal input. This is necessary in case a serial port is not completely wired. Though this affects PPS processing the patch is against the serial core as the source of the serial port PPS event dispatching has to be modified. Furthermore it should be possible to modify the source of serial port PPS event dispatching before changing the line discipline. Signed-off-by: Andreas Steinmetz Signed-off-by: Steve Sakoman Tested-by: Steve Sakoman Tested-by: Eric Gallimore Signed-off-by: Greg Kroah-Hartman

serial: 8250: introduce get_divisor() and set_divisor() hook

2018-07-12T15:07:26Z

Add these two hooks so that they can be overridden with driver specific implementations. Signed-off-by: Jisheng Zhang Reviewed-by: Andy Shevchenko Signed-off-by: Greg Kroah-Hartman

Merge 4.17-rc3 into tty-next

2018-04-30T12:14:55Z

We want the tty and serial driver fixes in here as well. Signed-off-by: Greg Kroah-Hartman