Pengfei Xu reports, that the -next commit 1788cf6a91 (tty: serial:
switch from circ_buf to kfifo) tries to emit a WARNING and that leads to
lockdep errors. Obviously we cannot print anything from uart_put_char()!
This WARN_ON_ONCE() was/is a debug aid to check if the condition in
uart_put_char() can happen at all. Pengfei Xu confirmed it can. Unlike
me and kbuild bot in my queue.
Second, I completely forgot about it, so I did not remove it in the
final version, nor mentioned it in the commit log.
Drop it now as we are all good. And we even have stack traces (and a
reproducer)!
Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Reported-by: Pengfei Xu <pengfei.xu@intel.com>
Link: https://lore.kernel.org/r/20240416071904.21440-1-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Marek reports, that the -next commit 1788cf6a91 (tty: serial: switch
from circ_buf to kfifo) broke meson_uart and qcom_geni_serial. The
commit mistakenly advanced the kfifo twice: once by
uart_fifo_get()/kfifo_out() and second time by uart_xmit_advance().
To advance the fifo only once, drop the superfluous uart_xmit_advance()
from both.
To count the TX statistics properly, use uart_fifo_out() in
qcom_geni_serial (meson_uart_start_tx() already uses that).
I checked all other uses of uart_xmit_advance() and they appear correct:
either they are finishing DMA transfers or are after peek/linear_ptr
(i.e. they do not advance fifo).
Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Fixes: 1788cf6a91 ("tty: serial: switch from circ_buf to kfifo")
Cc: Neil Armstrong <neil.armstrong@linaro.org>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Jerome Brunet <jbrunet@baylibre.com>
Cc: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Link: https://lore.kernel.org/r/20240416054825.6211-1-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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>
We are seeing start_tx being called after port shutdown as noted by Jiri.
This happens because we are missing the startup and shutdown related
functions for the serial base port.
Let's fix the issue by adding startup and shutdown functions for the
serial base port to block tx flushing for the serial base port when the
port is not in use.
Fixes: 84a9582fd2 ("serial: core: Start managing serial controllers to enable runtime PM")
Cc: stable <stable@kernel.org>
Reported-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20240411055848.38190-1-tony@atomide.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>
The circular buffer is NULLified in uart_tty_port_shutdown()
under the spin lock. However, the PM or other timer based callbacks
may still trigger after this event without knowning that buffer pointer
is not valid. Since the serial code is a bit inconsistent in checking
the buffer state (some rely on the head-tail positions, some on the
buffer pointer), it's better to have both aligned, i.e. buffer pointer
to be NULL and head-tail possitions to be the same, meaning it's empty.
This will prevent asynchronous calls to dereference NULL pointer as
reported recently in 8250 case:
BUG: kernel NULL pointer dereference, address: 00000cf5
Workqueue: pm pm_runtime_work
EIP: serial8250_tx_chars (drivers/tty/serial/8250/8250_port.c:1809)
...
? serial8250_tx_chars (drivers/tty/serial/8250/8250_port.c:1809)
__start_tx (drivers/tty/serial/8250/8250_port.c:1551)
serial8250_start_tx (drivers/tty/serial/8250/8250_port.c:1654)
serial_port_runtime_suspend (include/linux/serial_core.h:667 drivers/tty/serial/serial_port.c:63)
__rpm_callback (drivers/base/power/runtime.c:393)
? serial_port_remove (drivers/tty/serial/serial_port.c:50)
rpm_suspend (drivers/base/power/runtime.c:447)
The proposed change will prevent ->start_tx() to be called during
suspend on shut down port.
Fixes: 43066e3222 ("serial: port: Don't suspend if the port is still busy")
Cc: stable <stable@kernel.org>
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202404031607.2e92eebe-lkp@intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240404150034.41648-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The uart_handle_cts_change() function in serial_core expects the caller
to hold uport->lock. For example, I have seen the below kernel splat,
when the Bluetooth driver is loaded on an i.MX28 board.
[ 85.119255] ------------[ cut here ]------------
[ 85.124413] WARNING: CPU: 0 PID: 27 at /drivers/tty/serial/serial_core.c:3453 uart_handle_cts_change+0xb4/0xec
[ 85.134694] Modules linked in: hci_uart bluetooth ecdh_generic ecc wlcore_sdio configfs
[ 85.143314] CPU: 0 PID: 27 Comm: kworker/u3:0 Not tainted 6.6.3-00021-gd62a2f068f92 #1
[ 85.151396] Hardware name: Freescale MXS (Device Tree)
[ 85.156679] Workqueue: hci0 hci_power_on [bluetooth]
(...)
[ 85.191765] uart_handle_cts_change from mxs_auart_irq_handle+0x380/0x3f4
[ 85.198787] mxs_auart_irq_handle from __handle_irq_event_percpu+0x88/0x210
(...)
Cc: stable@vger.kernel.org
Fixes: 4d90bb147e ("serial: core: Document and assert lock requirements for irq helpers")
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Emil Kronborg <emil.kronborg@protonmail.com>
Link: https://lore.kernel.org/r/20240320121530.11348-1-emil.kronborg@protonmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit e5d6bd25f9 ("serial: 8250_dw: Do not reclock if already at
correct rate") breaks the dw UARTs on Intel Bay Trail (BYT) and
Cherry Trail (CHT) SoCs.
Before this change the RTL8732BS Bluetooth HCI which is found
connected over the dw UART on both BYT and CHT boards works properly:
Bluetooth: hci0: RTL: examining hci_ver=06 hci_rev=000b lmp_ver=06 lmp_subver=8723
Bluetooth: hci0: RTL: rom_version status=0 version=1
Bluetooth: hci0: RTL: loading rtl_bt/rtl8723bs_fw.bin
Bluetooth: hci0: RTL: loading rtl_bt/rtl8723bs_config-OBDA8723.bin
Bluetooth: hci0: RTL: cfg_sz 64, total sz 24508
Bluetooth: hci0: RTL: fw version 0x365d462e
where as after this change probing it fails:
Bluetooth: hci0: RTL: examining hci_ver=06 hci_rev=000b lmp_ver=06 lmp_subver=8723
Bluetooth: hci0: RTL: rom_version status=0 version=1
Bluetooth: hci0: RTL: loading rtl_bt/rtl8723bs_fw.bin
Bluetooth: hci0: RTL: loading rtl_bt/rtl8723bs_config-OBDA8723.bin
Bluetooth: hci0: RTL: cfg_sz 64, total sz 24508
Bluetooth: hci0: command 0xfc20 tx timeout
Bluetooth: hci0: RTL: download fw command failed (-110)
Revert the changes to fix this regression.
Fixes: e5d6bd25f9 ("serial: 8250_dw: Do not reclock if already at correct rate")
Cc: stable@vger.kernel.org
Cc: Peter Collingbourne <pcc@google.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Peter Collingbourne <pcc@google.com>
Link: https://lore.kernel.org/r/20240317214123.34482-1-hdegoede@redhat.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>
