Some MediaTek SoCs got a gated UART baud clock, which currently gets
disabled as the clk subsystem believes it would be unused. This results in
the uart freezing right after "clk: Disabling unused clocks" on those
platforms.
Request the baud clock to be prepared and enabled during probe, and to
restore run-time power management capabilities to what it was before commit
e32a83c70c ("serial: 8250-mtk: modify mtk uart power and clock
management") disable and unprepare the baud clock when suspending the UART,
prepare and enable it again when resuming it.
Fixes: e32a83c70c ("serial: 8250-mtk: modify mtk uart power and clock management")
Fixes: b6c7ff2693 ("serial: 8250_mtk: Simplify clock sequencing and runtime PM")
Cc: stable <stable@kernel.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Link: https://patch.msgid.link/de5197ccc31e1dab0965cabcc11ca92e67246cf6.1758058441.git.daniel@makrotopia.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Check the return value of reset_control_deassert() in the probe
function to prevent continuing probe when reset deassertion fails.
Previously, reset_control_deassert() was called without checking its
return value, which could lead to probe continuing even when the
device reset wasn't properly deasserted.
The fix checks the return value and returns an error with dev_err_probe()
if reset deassertion fails, providing better error handling and
diagnostics.
Fixes: acbdad8dd1 ("serial: 8250_dw: simplify optional reset handling")
Cc: stable <stable@kernel.org>
Signed-off-by: Artem Shimko <a.shimko.dev@gmail.com>
Link: https://patch.msgid.link/20251019095131.252848-1-a.shimko.dev@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To use guard()s easily in omap_8250_set_termios(), split it into atomic
and non-atomic part. The former can be easily guarded -- without a need
of indenting or moving code.
omap_8250_set_termios() would likely profit from a cleanup similar to
one in serial8250_do_set_termios() in commit cdc4a3e0b2 ("serial:
8250: extract serial8250_set_fcr()") and earlier.
Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20250814072456.182853-12-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Having all the new guards, use them in the 8250 code. This improves
readability, makes error handling easier, and marks locked portions of
code explicit.
serial_unlink_irq_chain() is done separately here because with the
guard() used, those BUG_ON()s can be switched WARN_ON()s as we can
actually handle the conditions and return (despite something went really
wrong).
Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20250814072456.182853-11-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Having this, guards like these work:
guard(serial8250_rpm)(up);
or
scoped_guard(serial8250_rpm, up) {
...
}
See e.g. "serial: 8250: use guard()s" later in this series.
And make them available to anyone (EXPORT + put in 8250.h) as drivers
open code this anyway.
The _tx ones are not defined as they would have no user.
Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20250814072456.182853-5-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The function serial8250_probe_platform() in 8250_platform.c triggered a
frame size warning:
drivers/tty/serial/8250/8250_platform.c: In function ‘serial8250_probe_platform.isra’:
drivers/tty/serial/8250/8250_platform.c:201:1: warning: the frame size of 1184 bytes is larger than 1024 bytes [-Wframe-larger-than=]
This patch reduces the stack usage by dynamically allocating the
`uart` structure using kzalloc(), rather than placing it on
the stack. This eliminates the overflow warning and improves kernel
robustness.
Signed-off-by: Abinash Singh <abinashsinghlalotra@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20250806215134.4921-3-abinashsinghlalotra@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The function serial8250_probe_acpi() in 8250_platform.c triggered a
frame size warning:
drivers/tty/serial/8250/8250_platform.c: In function ‘serial8250_probe_acpi’:
drivers/tty/serial/8250/8250_platform.c:152:1: warning: the frame size of 1160 bytes is larger than 1024 bytes [-Wframe-larger-than=]
This patch reduces the stack usage by dynamically allocating the
`uart` structure using kzalloc(), rather than placing it on
the stack. This eliminates the overflow warning and improves kernel
robustness.
Signed-off-by: Abinash Singh <abinashsinghlalotra@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20250806215134.4921-2-abinashsinghlalotra@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
I am switching my address to a personal domain, so some files in the
SGI IP30 and IOC3 files need to be updated. I will send updates for
the MAINTAINERS file and rtc-ds1685 separately to linux-rtc.
Signed-off-by: Joshua Kinard <kumba@gentoo.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
When the PSLVERR_RESP_EN parameter is set to 1, the device generates
an error response if an attempt is made to read an empty RBR (Receive
Buffer Register) while the FIFO is enabled.
In serial8250_do_startup(), calling serial_port_out(port, UART_LCR,
UART_LCR_WLEN8) triggers dw8250_check_lcr(), which invokes
dw8250_force_idle() and serial8250_clear_and_reinit_fifos(). The latter
function enables the FIFO via serial_out(p, UART_FCR, p->fcr).
Execution proceeds to the serial_port_in(port, UART_RX).
This satisfies the PSLVERR trigger condition.
When another CPU (e.g., using printk()) is accessing the UART (UART
is busy), the current CPU fails the check (value & ~UART_LCR_SPAR) ==
(lcr & ~UART_LCR_SPAR) in dw8250_check_lcr(), causing it to enter
dw8250_force_idle().
Put serial_port_out(port, UART_LCR, UART_LCR_WLEN8) under the port->lock
to fix this issue.
Panic backtrace:
[ 0.442336] Oops - unknown exception [#1]
[ 0.442343] epc : dw8250_serial_in32+0x1e/0x4a
[ 0.442351] ra : serial8250_do_startup+0x2c8/0x88e
...
[ 0.442416] console_on_rootfs+0x26/0x70
Fixes: c49436b657 ("serial: 8250_dw: Improve unwritable LCR workaround")
Link: https://lore.kernel.org/all/84cydt5peu.fsf@jogness.linutronix.de/T/
Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Cc: stable <stable@kernel.org>
Link: https://lore.kernel.org/r/20250723023322.464-2-cuiyunhui@bytedance.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The RSA functions moved by the below commit to 8250_rsa.c are used in
8250_base.c. Since that can be a module (when CONFIG_SERIAL_8250=m),
this causes build failures:
ERROR: modpost: "rsa_autoconfig" [drivers/tty/serial/8250/8250_base.ko] undefined!
ERROR: modpost: "rsa_reset" [drivers/tty/serial/8250/8250_base.ko] undefined!
ERROR: modpost: "rsa_disable" [drivers/tty/serial/8250/8250_base.ko] undefined!
ERROR: modpost: "rsa_enable" [drivers/tty/serial/8250/8250_base.ko] undefined!
Fix them by exporting the functions. But only to the base module using
EXPORT_SYMBOL_GPL_FOR_MODULES(). (And not to the whole world.)
Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Link: https://lore.kernel.org/all/20250619165607.33403e19@canb.auug.org.au/
Fixes: 5a128fb475 ("serial: 8250: move RSA functions to 8250_rsa.c")
Link: https://lore.kernel.org/r/20250623061035.436414-1-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
There is no point in a long 'if' in serial8250_register_8250_port() to
just return ENOSPC for PORT_8250_CIR ports. Invert the condition and
return immediately.
'gpios' variable was moved to its set location.
And return ENODEV instead of ENOSPC. The latter is a leftover from the
previous find-uart 'if'. The former makes a lot more sense in this case.
Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20250611100319.186924-31-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This find-or-create-irq part of the serial_link_irq_chain()'s code is
logically bounded and self-standing. For easier-to-follow code flow,
extract the code to a separate function:
serial_get_or_create_irq_info().
This allows for an easier found-an-irq handling -- simple jump to the
'unlock' label and return. That results in one less 'if' levels.
Note when using guard()s in the upcoming patchset, the label can dropped
altogether.
Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20250611100319.186924-28-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial8250_do_startup() contains a stand-alone code for probing THRE.
Furthermore, the code block is conditional (port->irq and test for
UPF_NO_THRE_TEST).
Move this code to a separate function. The conditional can be evaluated
easier there -- by a simple return in the beginning. So the indentation
level lowers and the code is overall more readable now.
Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20250611100319.186924-16-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
