When terminal is unresponsive, one cannot use dmesg to view
the printk ring buffer messages. Also, syslog services may be
disabled, especially on embedded systems, to check the messages
after a reboot. In this scenario, replay the messages in printk
ring buffer on consoles via sysrq by pressing sysrq+R.
The console loglevel will determine which all kernel log messages
are displayed. The messages will be displayed only when
console_trylock() succeeds. Users could repeat the sysrq key when
it fails. If the owner of console subsystem lock is stuck,
repeating the key won't work.
Suggested-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Shimoyashiki Taichi <taichi.shimoyashiki@sony.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Sreenath Vijayan <sreenath.vijayan@sony.com>
Link: https://lore.kernel.org/r/cc3b9b1aae60a236c6aed1dc7b0ffa2c7cd1f183.1710220326.git.sreenath.vijayan@sony.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add a generic function console_replay_all() for replaying
the kernel log on consoles, in any context. It would allow
viewing the logs on an unresponsive terminal via sysrq.
Reuse the existing code from console_flush_on_panic() for
resetting the sequence numbers, by introducing a new helper
function __console_rewind_all(). It is safe to be called
under console_lock().
Try to acquire lock on the console subsystem without waiting.
If successful, reset the sequence number to oldest available
record on all consoles and call console_unlock() which will
automatically flush the messages to the consoles.
Suggested-by: John Ogness <john.ogness@linutronix.de>
Suggested-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Shimoyashiki Taichi <taichi.shimoyashiki@sony.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Sreenath Vijayan <sreenath.vijayan@sony.com>
Link: https://lore.kernel.org/r/90ee131c643a5033d117b556c0792de65129d4c3.1710220326.git.sreenath.vijayan@sony.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Variable tmout is being assigned a value that is never read, it is
being re-assinged in the following for-loop statement. The assignment
is redundant and can be removed.
Cleans up clang scan warning:
drivers/tty/serial/omap-serial.c:1096:3: warning: Value stored to 'tmout'
is never read [deadcode.DeadStores]
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Link: https://lore.kernel.org/r/20240411085537.306020-1-colin.i.king@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We need to inline serial_base_add_isa_preferred_console() based on
CONFIG_SERIAL_8250_CONSOLE and not based on CONFIG_SERIAL_CORE_CONSOLE.
Otherwise we can get the follwoing error as noted by Stephen:
ERROR: modpost: "serial_base_add_isa_preferred_console"
[drivers/tty/serial/8250/8250.ko] undefined!
We also have a duplicate inlined serial_base_add_isa_preferred_console(),
in serial_base_bus.c added by the same commit by accident, let's drop it.
Fixes: a8b04cfe7d ("serial: 8250: Add preferred console in serial8250_isa_init_ports()")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20240411080622.11929-1-tony@atomide.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Split the common code from sc16is7xx driver and move the I2C and SPI bus
parts into interface-specific source files.
sc16is7xx becomes the core functions which can support multiple bus
interfaces like I2C and SPI.
No functional changes intended.
Also simplify and improve Kconfig entries.
- Capitalize SPI keyword for consistency
- Display list of supported ICs each on a separate line (and aligned) to
facilitate locating a specific IC model
- Add Manufacturer name at start of description string
- Add UART keyword to description string
Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20240409154253.3043822-4-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Sparse is not happy about misuse of bitwise types:
.../max3100.c:194:13: warning: incorrect type in assignment (different base types)
.../max3100.c:194:13: expected unsigned short [addressable] [usertype] etx
.../max3100.c:194:13: got restricted __be16 [usertype]
.../max3100.c:202:15: warning: cast to restricted __be16
Fix this by choosing proper types for the respective variables.
Fixes: 7831d56b0a ("tty: MAX3100")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240402195306.269276-4-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The removal of the last MAX3100 device triggers the removal of
the driver. However, code doesn't update the respective global
variable and after insmod — rmmod — insmod cycle the kernel
oopses:
max3100 spi-PRP0001:01: max3100_probe: adding port 0
BUG: kernel NULL pointer dereference, address: 0000000000000408
...
RIP: 0010:serial_core_register_port+0xa0/0x840
...
max3100_probe+0x1b6/0x280 [max3100]
spi_probe+0x8d/0xb0
Update the actual state so next time UART driver will be registered
again.
Hugo also noticed, that the error path in the probe also affected
by having the variable set, and not cleared. Instead of clearing it
move the assignment after the successfull uart_register_driver() call.
Fixes: 7831d56b0a ("tty: MAX3100")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20240402195306.269276-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
uart_handle_cts_change() has to be called with port lock taken,
Since we run it in a separate work, the lock may not be taken at
the time of running. Make sure that it's taken by explicitly doing
that. Without it we got a splat:
WARNING: CPU: 0 PID: 10 at drivers/tty/serial/serial_core.c:3491 uart_handle_cts_change+0xa6/0xb0
...
Workqueue: max3100-0 max3100_work [max3100]
RIP: 0010:uart_handle_cts_change+0xa6/0xb0
...
max3100_handlerx+0xc5/0x110 [max3100]
max3100_work+0x12a/0x340 [max3100]
Fixes: 7831d56b0a ("tty: MAX3100")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240402195306.269276-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The UART's input clock rate can change at runtime but this is not
handled by the driver.
Add a clock_notifier callback that updates the divisors when the input
clock is updated. The serial8250_update_uartclk() is used to do so.
PRE_RATE_CHANGE and ABORT_RATE_CHANGE notifications are ignored, only
the POST_RATE_CHANGE is used. Not using PRE_RATE_CHANGE notification can
result in a few corrupted bytes during frequency transitions but, IMHO,
it can be acceptable in many use cases.
It has been tested on a DAVINCI/OMAP-L138 processor.
Signed-off-by: Bastien Curutchet <bastien.curutchet@bootlin.com>
Reviewed-by: Herve Codina <herve.codina@bootlin.com>
Link: https://lore.kernel.org/r/20240405120552.35991-1-bastien.curutchet@bootlin.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
There are considerations to drop platform_driver_probe() as a concept
that isn't relevant any more today. It comes with an added complexity
that makes many users hold it wrong. (E.g. this driver should have
marked the driver struct with __refdata to prevent the below mentioned
false positive section mismatch warning.)
This fixes a W=1 build warning:
WARNING: modpost: drivers/tty/serial/pmac_zilog: section mismatch in reference: pmz_driver+0x8 (section: .data) -> pmz_detach (section: .exit.text)
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/5ea3174616abc9fa256f115b4fb175d289ac1754.1711748999.git.u.kleine-koenig@pengutronix.de
Tested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This change strips $abs_srctree of the input file containing the
character mapping table in the generated output. The motivation for this
change is Yocto emitting a build warning
WARNING: linux-lxatac-6.7-r0 do_package_qa: QA Issue: File /usr/src/debug/linux-lxatac/6.7-r0/drivers/tty/vt/consolemap_deftbl.c in package linux-lxatac-src contains reference to TMPDIR
So this change brings us one step closer to make the build result
reproducible independent of the build path.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20240311113017.483101-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The driver is using "sifive,fu540-c000-uart0" as a binding. The device
tree and documentation states "sifive,fu540-c000-uart" instead. This
means the binding is not matched and not used.
This did not cause any problems because the alternative binding, used in
the device tree, "sifive,uart0" is not handling the hardware any
different.
Align the binding in the driver with the documentation.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240307090950.eLELkuyK@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Prepare 8250 ISA ports to drop kernel command line serial console
handling from console_setup().
We need to set the preferred console in serial8250_isa_init_ports()
to drop a dependency to setup_console() handling the ttyS related
quirks. Otherwise when console_setup() handles the ttyS related
options, console gets enabled only at driver probe time.
Note that this mostly affects x86 as this happens based on define
SERIAL_PORT_DFNS.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20240327110021.59793-7-tony@atomide.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In order to start moving the serial console quirks out of console_setup(),
let's add parsing for the quirks to the serial core layer. We can use
serial_base_add_one_prefcon() to handle the quirks.
Note that eventually we may want to set up driver specific console quirk
handling for the serial port device drivers to use. But we need to figure
out which driver(s) need to call the quirk. So for now, we just handle the
sparc quirk directly.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20240327110021.59793-6-tony@atomide.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We can now add hardware based addressing for serial ports. Starting with
commit 84a9582fd2 ("serial: core: Start managing serial controllers to
enable runtime PM"), and all the related fixes to this commit, the serial
core now knows to which serial port controller the ports are connected.
The serial ports can be addressed with DEVNAME:0.0 style naming. The names
are something like 00:04:0.0 for a serial port on qemu, and something like
2800000.serial:0.0 on platform device using systems like ARM64 for example.
The DEVNAME is the unique serial port hardware controller device name, AKA
the name for port->dev. The 0.0 are the serial core controller id and port
id.
Typically 0.0 are used for each controller and port instance unless the
serial port hardware controller has multiple controllers or ports.
Using DEVNAME:0.0 style naming actually solves two long term issues for
addressing the serial ports:
1. According to Andy Shevchenko, using DEVNAME:0.0 style naming fixes an
issue where depending on the BIOS settings, the kernel serial port ttyS
instance number may change if HSUART is enabled
2. Device tree using architectures no longer necessarily need to specify
aliases to find a specific serial port, and we can just allocate the
ttyS instance numbers dynamically in whatever probe order
To do this, let's match the hardware addressing style console name to
the character device name used, and add a preferred console using the
character device name.
Note that when using console=DEVNAME:0.0 style kernel command line, the
8250 serial console gets enabled later compared to using console=ttyS
naming for ISA ports. This is because the serial port DEVNAME to character
device mapping is not known until the serial driver probe time. If used
together with earlycon, this issue is avoided.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Dhruva Gole <d-gole@ti.com>
Link: https://lore.kernel.org/r/20240327110021.59793-5-tony@atomide.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If add_preferred_console() is not called early in setup_console(), we can
end up having register_console() call try_enable_default_console() before a
console device has called add_preferred_console().
Let's set console_set_on_cmdline flag in console_setup() to prevent this
from happening.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20240327110021.59793-4-tony@atomide.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
