Add UART_CAP_NOTEMT for UARTs that lack interrupt on TEMT but want to
use em485. Em485 framework needs to ensure not only FIFO is empty but
also that tx shift register is empty.
This approach uses Uwe Kleine-König's suggestion on simply
using/incrementing stop_tx timer rather than adding another timer. When
UART_CAP_NOTEMT is set and THRE is present w/o TEMT, stop tx timer is
reused to wait for the emptying of the shift register.
This change does not add the UART_CAP_NOTEMT define as it already exist
but is currently no-op. See 7a107b2c6b (Revert "serial: 8250: Handle
UART without interrupt on TEMT using em485") for further details.
Vicente Bergas reported that RTS is deasserted roughly one bit too
early losing stop bit tx. To address this problem, stop_delay now
accounts for one extra bit using rough formula /7 (assumes worst-case
of 2+5 bits). I suspect this glitch had to do with when THRE is getting
asserted. If FIFO is emptied already during the tx of the stop bit,
perhaps it leads to HW asserting THRE early for the normal frame time
formula to work accurately.
Suggested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Eric Tremblay <etremblay@distech-controls.com>
Tested-by: Vicente Bergas <vicencb@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220425143410.12703-4-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
8250 DMA tx complete path lacks calls to normal 8250 stop handling. It
does not use THRE to detect true completion of the tx and also doesn't
call __stop_tx. This leads to problems with em485 that needs to handle
RTS timing.
Instead of handling tx stop internally within 8250 dma code, enable
THRE when tx'able data runs out and tweak serial8250_handle_irq to call
only __stop_tx when uart is using DMA.
It also seems bit early to call serial8250_rpm_put_tx from there while
tx is still underway(?).
Tested-by: Vicente Bergas <vicencb@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220425143410.12703-3-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Struct uart_port currently stores FIFO timeout. Having character timing
information readily available is useful. Even serial core itself
determines char_time from port->timeout using inverse calculation.
Store frame_time directly into uart_port. Character time is stored in
nanoseconds to have reasonable precision with high rates. To avoid
overflow, 64-bit math is necessary.
It might be possible to determine timeout from frame_time by
multiplying it with fifosize as needed but only part of the users seem
to be protected by a lock. Thus, this patch does not pursue storing
only frame_time in uart_port.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220425143410.12703-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
DW based controllers like the one on Renesas RZ/N1 must be programmed as
flow controllers when using DMA.
* Table 11.45 of the system manual, "Flow Control Combinations", states
that using UART with DMA requires setting the DMA in the peripheral
flow controller mode regardless of the direction.
* Chapter 11.6.1.3 of the system manual, "Basic Interface Definitions",
explains that the burst size in the above case must be configured in
the peripheral's register DEST/SRC_BURST_SIZE.
Experiments shown that upon Rx timeout, the DMA transaction needed to be
manually cleared as well.
Co-developed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20220422180615.9098-9-miquel.raynal@bootlin.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Use device tree match data rather than multiple calls to
of_device_is_compatible() by introducing a platform data structure and
adding a quirks mask.
Provide a stub to the compatibles without quirks to simplify the
handling of the upcoming changes.
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
[<miquel.raynal@bootlin.com: Minor changes + creation of a real pdata structure]
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20220422180615.9098-3-miquel.raynal@bootlin.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The EndRun PTP/1588 dual serial port device is based on the Oxford
Semiconductor OXPCIe952 UART device with the PCI vendor:device ID set
for EndRun Technologies and is therefore driven by a fixed 62.5MHz clock
input derived from the 100MHz PCI Express clock. The clock rate is
divided by the oversampling rate of 16 as it is supplied to the baud
rate generator, yielding the baud base of 3906250.
Replace the incorrect baud base of 4000000 with the right value of
3906250 then, complementing commit 6cbe45d8ac ("serial: 8250: Correct
the clock for OxSemi PCIe devices").
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Cc: stable <stable@kernel.org>
Fixes: 1bc8cde46a ("8250_pci: Added driver for Endrun Technologies PTP PCIe card.")
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2204181515270.9383@angie.orcam.me.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Do not set timeout to twice the approximate amount of time to send the
entire FIFO if CTS is enabled. If the caller requested no timeout, e.g.
when userspace program called tcdrain(), then wait without any timeout.
Premature return from tcdrain() was observed on imx based system which
has 32 character long transmitter FIFO with hardware CTS handling.
Simple userspace application that reproduces problem has to:
* Open tty device, enable hardware flow control (CRTSCTS)
* Write data, e.g. 26 bytes
* Call tcdrain() to wait for the transmitter
* Close tty device
The other side of serial connection has to:
* Receive some data, e.g. 10 bytes
* Set RTS output (CTS input from sender perspective) inactive for
at least twice the port timeout
* Try to receive remaining data
Without this patch, userspace application will finish without any error
while the other side of connection will never receive remaining data.
Signed-off-by: Tomasz Moń <tomasz.mon@camlingroup.com>
Link: https://lore.kernel.org/r/20220228054911.1420221-1-tomasz.mon@camlingroup.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Note: I am using a small test app + driver located at [0] for the
problem description. serco is a driver whose write function dispatches
to the serial controller. sertest is a user-mode app that writes n bytes
to the serial console using the serco driver.
While investigating a bug in the RHEL kernel, I noticed that the serial
console throughput is way below the configured speed of 115200 bps in
a HP Proliant DL380 Gen9. I was expecting something above 10KB/s, but
I got 2.5KB/s.
$ time ./sertest -n 2500 /tmp/serco
real 0m0.997s
user 0m0.000s
sys 0m0.997s
With the help of the function tracer, I then noticed the serial
controller was taking around 410us seconds to dispatch one single byte:
$ trace-cmd record -p function_graph -g serial8250_console_write \
./sertest -n 1 /tmp/serco
$ trace-cmd report
| serial8250_console_write() {
0.384 us | _raw_spin_lock_irqsave();
1.836 us | io_serial_in();
1.667 us | io_serial_out();
| uart_console_write() {
| serial8250_console_putchar() {
| wait_for_xmitr() {
1.870 us | io_serial_in();
2.238 us | }
1.737 us | io_serial_out();
4.318 us | }
4.675 us | }
| wait_for_xmitr() {
1.635 us | io_serial_in();
| __const_udelay() {
1.125 us | delay_tsc();
1.429 us | }
...
...
...
1.683 us | io_serial_in();
| __const_udelay() {
1.248 us | delay_tsc();
1.486 us | }
1.671 us | io_serial_in();
411.342 us | }
In another machine, I measured a throughput of 11.5KB/s, with the serial
controller taking between 80-90us to send each byte. That matches the
expected throughput for a configuration of 115200 bps.
This patch changes the serial8250_console_write to use the 16550 fifo
if available. In my benchmarks I got around 25% improvement in the slow
machine, and no performance penalty in the fast machine.
Signed-off-by: Wander Lairson Costa <wander@redhat.com>
Link: https://lore.kernel.org/r/20220411174841.34936-2-wander@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
There is a deadlock in sa1100_set_termios(), which is shown
below:
(Thread 1) | (Thread 2)
| sa1100_enable_ms()
sa1100_set_termios() | mod_timer()
spin_lock_irqsave() //(1) | (wait a time)
... | sa1100_timeout()
del_timer_sync() | spin_lock_irqsave() //(2)
(wait timer to stop) | ...
We hold sport->port.lock in position (1) of thread 1 and
use del_timer_sync() to wait timer to stop, but timer handler
also need sport->port.lock in position (2) of thread 2. As a result,
sa1100_set_termios() will block forever.
This patch moves del_timer_sync() before spin_lock_irqsave()
in order to prevent the deadlock.
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Link: https://lore.kernel.org/r/20220417111626.7802-1-duoming@zju.edu.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Some more serial drivers can be compile-tested under certain
circumstances (when building a specific architecture). So allow for
that.
This reduces the need of zillion mach/subarch-specific configs. And
since the 0day bot has only allmodconfig's for some archs, this
increases build coverage there too.
Note that cpm needs a minor update in the header, so that it drags in
at least some defines (CPM2 ones).
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220421101708.5640-8-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pic32_uart contains this:
#ifdef CONFIG_SERIAL_PIC32_CONSOLE
...
console_initcall(pic32_console_init);
...
core_initcall(pic32_late_console_init);
...
#endif
...
arch_initcall(pic32_uart_init);
When the driver is built as module, all three above become
module_init(). So if SERIAL_PIC32_CONSOLE is set while SERIAL_PIC32=m,
it results in the following build error:
In file included from include/linux/device/driver.h:21,
from include/linux/device.h:32,
from include/linux/platform_device.h:13,
from drivers/tty/serial/pic32_uart.c:12:
include/linux/module.h:131:49: error: redefinition of '__inittest'
So make sure SERIAL_PIC32_CONSOLE can be set only when SERIAL_PIC32=y --
similar as for other drivers.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220421101708.5640-7-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Use list_for_each_entry() helper instead of explicit combo of
list_for_each() and list_entry().
Note that pos is used as a reference point in list_add_tail() in
icom_alloc_adapter(). This functionality remains as with an empty list,
cur_adapter_entry->icom_adapter_entry is still the list head.
This simplifies the code a bit.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220421085808.24152-9-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
There is a lot of sparse warnings:
.../icom.c:228:30: warning: cast from restricted __le16
.../icom.c:232:66: warning: incorrect type in assignment (different base types)
.../icom.c:232:66: expected unsigned int [usertype] leBuffer
.../icom.c:232:66: got restricted __le32 [usertype]
.../icom.c:237:30: warning: cast from restricted __le16
...
.../icom.c:1228:22: warning: cast from restricted __le16
And they are correct. So sort them all out by using proper __leXX and
uXX types and the right direction of conversion: le16_to_cpu() instead
of cpu_to_le16(), where appropriate.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220421085808.24152-5-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In icom, there is an ICOM_PORT macro to perform upcasts from struct
uart_port to struct icom_port. It's not completely safe and it works
only because the first member of icom_port is uart_port. Nowadays, we
use container_of for such an upcast instead.
So introduce a helper (to_icom_port()) with container_of in it and
convert all the ICOM_PORT users to the new helper. Apart from the code
and type safety, it's also clear what icom_port (the variable) is.
Unlike with the old ICOM_PORT (the macro with the cast).
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220421085808.24152-3-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
As a preparation for cleaning up the omap1 headers, start
including linux/soc/ti/omap1-soc.h directly so we can
keep calling cpu_is_omap1510().
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
This partially reverts commit f6f586102a. The code added by
that commit containted math overflow for 32-bit archs. In
addition, the approach used in it is unnecessarily complicated
requiring a dedicated timer just for notemt. A simpler approach
for providing UART_CAP_NOTEMT already exists (patches 1-2):
https://lore.kernel.org/linux-serial/20220411083321.9131-3-ilpo.jarvinen@linux.intel.com/T/#u
Thus, simply revert the UART_CAP_NOTEMT change for now.
There were two driver changes within the patch series adding
UART_CAP_NOTEMT taking advantage of the newly added flag.
This does not revert the driver changes and therefore also
UART_CAP_NOTEMT define has to remain. UART_CAP_NOTEMT remains
no-op until support is again added.
Fixes: f6f586102a ("serial: 8250: Handle UART without interrupt on TEMT using em485")
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/5f874142-fb1f-bff7-f33-fac823e65e2e@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 76821e222c ("serial: imx: ensure that RX irqs are off if RX is
off") accidentally enabled overrun interrupts unconditionally when
deferring DMA enable until after the receiver has been enabled during
startup.
Fix this by using the DMA-initialised instead of DMA-enabled flag to
determine whether overrun interrupts should be enabled.
Note that overrun interrupts are already accounted for in
imx_uart_clear_rx_errors() when using DMA since commit 41d98b5da9
("serial: imx-serial - update RX error counters when DMA is used").
Fixes: 76821e222c ("serial: imx: ensure that RX irqs are off if RX is off")
Cc: stable@vger.kernel.org # 4.17
Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20220411081957.7846-1-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The current timeout for draining the tx fifo in RS485 mode is calculated by
multiplying the time it takes to transmit one character (with the given
baud rate) with the maximal number of characters in the tx queue.
This timeout is too short for two reasons:
First when calculating the time to transmit one character integer division
is used which may round down the result in case of a remainder of the
division.
Fix this by rounding up the division result.
Second the hardware may need additional time (e.g for first putting the
characters from the fifo into the shift register) before the characters are
actually put onto the wire.
To be on the safe side double the current maximum number of iterations
that are used to wait for the queue draining.
Fixes: 8d47923772 ("serial: amba-pl011: add RS485 support")
Cc: stable@vger.kernel.org
Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Link: https://lore.kernel.org/r/20220408233503.7251-1-LinoSanfilippo@gmx.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Now fsl_lpuart driver use both of_alias_get_id() and ida_simple_get() in
.probe(), which has the potential bug. For example, when remove the
lpuart7 alias in dts, of_alias_get_id() will return error, then call
ida_simple_get() to allocate the id 0 for lpuart7, this may confilct
with the lpuart4 which has alias 0.
aliases {
...
serial0 = &lpuart4;
serial1 = &lpuart5;
serial2 = &lpuart6;
serial3 = &lpuart7;
}
So remove the ida_simple_get() in .probe(), return an error directly
when calling of_alias_get_id() fails, which is consistent with other
uart drivers behavior.
Fixes: 3bc3206e1c ("serial: fsl_lpuart: Remove the alias node dependence")
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20220321112211.8895-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When flow control is enabled, the UART should set RTS to false
during suspend to stop incoming data. Currently, the suspend
routine sets the mctrl register in the uart to zero, but leaves
the shadow version in the uart_port struct alone so that resume
can restore it. This causes a problem later in suspend when
serial8250_do_shutdown() is called which uses the shadow mctrl
register to clear some additional bits but ends up restoring RTS.
The solution is to clear RTS from the shadow version before
serial8250_do_shutdown() is called and restore it after.
Signed-off-by: Al Cooper <alcooperx@comcast.net>
Link: https://lore.kernel.org/r/20220324145620.41573-1-alcooperx@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
