Oxford Semiconductor PCIe (Tornado) 950 serial port devices are driven
by a fixed 62.5MHz clock input derived from the 100MHz PCI Express clock.
We currently drive the device using its default oversampling rate of 16
and the clock prescaler disabled, consequently yielding the baud base of
3906250. This base is inadequate for some of the high-speed baud rates
such as 460800bps, for which the closest rate possible can be obtained
by dividing the baud base by 8, yielding the baud rate of 488281.25bps,
which is off by 5.9638%. This is enough for data communication to break
with the remote end talking actual 460800bps, where missed stop bits
have been observed.
We can do better however, by taking advantage of a reduced oversampling
rate, which can be set to any integer value from 4 to 16 inclusive by
programming the TCR register, and by using the clock prescaler, which
can be set to any value from 1 to 63.875 in increments of 0.125 in the
CPR/CPR2 register pair. The prescaler has to be explicitly enabled
though by setting bit 7 in the MCR or otherwise it is bypassed (in the
enhanced mode that we enable) as if the value of 1 was used.
Make use of these features then as follows:
- Set the baud base to 15625000, reflecting the minimum oversampling
rate of 4 with the clock prescaler and divisor both set to 1.
- Override the `set_mctrl' and set the MCR shadow there so as to have
MCR[7] always set and have the 8250 core propagate these settings.
- Override the `get_divisor' handler and determine a good combination of
parameters by using a lookup table with predetermined value pairs of
the oversampling rate and the clock prescaler and finding a pair that
divides the input clock such that the quotient, when rounded to the
nearest integer, deviates the least from the exact result. Calculate
the clock divisor accordingly.
Scale the resulting oversampling rate (only by powers of two) if
possible so as to maximise it, reducing the divisor accordingly, and
avoid a divisor overflow for very low baud rates by scaling the
oversampling rate and/or the prescaler even if that causes some
accuracy loss.
Also handle the historic spd_cust feature so as to allow one to set
all the three parameters manually to arbitrary values, by keeping the
low 16 bits for the divisor and then putting TCR in bits 19:16 and
CPR/CPR2 in bits 28:20, sanitising the bit pattern supplied such as
to clamp CPR/CPR2 values between 0.000 and 0.875 inclusive to 33.875.
This preserves compatibility with any existing setups, that is where
requesting a custom divisor that only has any bits set among the low
16 the oversampling rate of 16 and the clock prescaler of 33.875 will
be used as with the original 8250.
Finally abuse the `frac' argument to store the determined bit patterns
for the TCR, CPR and CPR2 registers.
- Override the `set_divisor' handler so as to set the TCR, CPR and CPR2
registers from the `frac' value supplied. Set the divisor as usual.
With the baud base set to 15625000 and the unsigned 16-bit UART_DIV_MAX
limitation imposed by `serial8250_get_baud_rate' standard baud rates
below 300bps become unavailable in the regular way, e.g. the rate of
200bps requires the baud base to be divided by 78125 and that is beyond
the unsigned 16-bit range. The historic spd_cust feature can still be
used to obtain such rates if so required.
See Documentation/tty/device_drivers/oxsemi-tornado.rst for more details.
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2204181519450.9383@angie.orcam.me.uk
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 uses the same sequence to determine the
number of ports available. Despite that we have duplicate code
specific to the EndRun device.
Remove redundant code then and factor out OxSemi Tornado device
detection.
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2204181516220.9383@angie.orcam.me.uk
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>
Provide information in the kernel log as to what configuration option to
enable for PCI UART devices that have been blacklisted in the generic
PCI 8250 UART driver and which have a dedicated driver available to
handle that has been disabled. The rationale is there is no easy way
for the user to map a specific PCI vendor:device pair to an individual
dedicated driver while the generic driver has this information readily
available and it will likely be confusing that the generic driver does
not register such a port.
This is unlike usual drivers, such as drivers/net/ethernet/3com/3c59x.c
which handles all the hardware family members regardless of differences
between them, and following an existing example where a serio driver
provides suggestions as to the correct configuration options to use:
psmouse serio1: synaptics: The touchpad can support a better bus than the too old PS/2 protocol. Make sure MOUSE_PS2_SYNAPTICS_SMBUS and RMI4_SMB are enabled to get a better touchpad experience.
A message is then printed like:
serial 0000:04:00.3: ignoring port, enable SERIAL_8250_PERICOM to handle
when an affected device is encountered and the generic driver rejects it.
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2203310054120.44113@angie.orcam.me.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Have pericom_do_set_divisor() use the uartclk instead of a hard coded
value to work with different speed crystals. Tested with 14.7456 and 24
MHz crystals.
Have pericom_do_set_divisor() always calculate the divisor rather than
call serial8250_do_set_divisor() for rates below baud_base.
Do not write registers or call serial8250_do_set_divisor() if valid
divisors could not be found.
Fixes: 6bf4e42f1d ("serial: 8250: Add support for higher baud rates to Pericom chips")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Jay Dolan <jay.dolan@accesio.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20211122120604.3909-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This attempts to fix a bug found with a serial port card which uses
an MCS9922 chip, one of the 4 models for which MSI-X interrupts are
currently supported. I don't possess such a card, and i'm not
experienced with the serial subsystem, so this patch is based on what
i think i found as a likely reason for failure, based on walking the
user who actually owns the card through some diagnostic.
The user who reported the problem finds the following in his dmesg
output for the relevant ttyS4 and ttyS5:
[ 0.580425] serial 0000:02:00.0: enabling device (0000 -> 0003)
[ 0.601448] 0000:02:00.0: ttyS4 at I/O 0x3010 (irq = 125, base_baud = 115200) is a ST16650V2
[ 0.603089] serial 0000:02:00.1: enabling device (0000 -> 0003)
[ 0.624119] 0000:02:00.1: ttyS5 at I/O 0x3000 (irq = 126, base_baud = 115200) is a ST16650V2
...
[ 6.323784] genirq: Flags mismatch irq 128. 00000080 (ttyS5) vs. 00000000 (xhci_hcd)
[ 6.324128] genirq: Flags mismatch irq 128. 00000080 (ttyS5) vs. 00000000 (xhci_hcd)
...
Output of setserial -a:
/dev/ttyS4, Line 4, UART: 16650V2, Port: 0x3010, IRQ: 127
Baud_base: 115200, close_delay: 50, divisor: 0
closing_wait: 3000
Flags: spd_normal skip_test
This suggests to me that the serial driver wants to register and share a
MSI/MSI-X irq 128 with the xhci_hcd driver, whereas the xhci driver does
not want to share the irq, as flags 0x00000080 (== IRQF_SHARED) from the
serial port driver means to share the irq, and this mismatch ends in some
failed irq init?
With this setup, data reception works very unreliable, with dropped data,
already at a transmission rate of only a 16 Bytes chunk every 1/120th of
a second, ie. 1920 Bytes/sec, presumably due to rx fifo overflow due to
mishandled or not used at all rx irq's?
See full discussion thread with attempted diagnosis at:
https://psychtoolbox.discourse.group/t/issues-with-iscan-serial-port-recording/3886
Disabling the use of MSI interrupts for the serial port pci card did
fix the reliability problems. The user executed the following sequence
of commands to achieve this:
echo 0000:02:00.0 | sudo tee /sys/bus/pci/drivers/serial/unbind
echo 0000:02:00.1 | sudo tee /sys/bus/pci/drivers/serial/unbind
echo 0 | sudo tee /sys/bus/pci/devices/0000:02:00.0/msi_bus
echo 0 | sudo tee /sys/bus/pci/devices/0000:02:00.1/msi_bus
echo 0000:02:00.0 | sudo tee /sys/bus/pci/drivers/serial/bind
echo 0000:02:00.1 | sudo tee /sys/bus/pci/drivers/serial/bind
This resulted in the following log output:
[ 82.179021] pci 0000:02:00.0: MSI/MSI-X disallowed for future drivers
[ 87.003031] pci 0000:02:00.1: MSI/MSI-X disallowed for future drivers
[ 98.537010] 0000:02:00.0: ttyS4 at I/O 0x3010 (irq = 17, base_baud = 115200) is a ST16650V2
[ 103.648124] 0000:02:00.1: ttyS5 at I/O 0x3000 (irq = 18, base_baud = 115200) is a ST16650V2
This patch attempts to fix the problem by disabling irq sharing when
using MSI irq's. Note that all i know for sure is that disabling MSI
irq's fixed the problem for the user, so this patch could be wrong and
is untested. Please review with caution, keeping this in mind.
Fixes: 8428413b1d ("serial: 8250_pci: Implement MSI(-X) support")
Cc: Ralf Ramsauer <ralf.ramsauer@oth-regensburg.de>
Cc: stable <stable@vger.kernel.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Link: https://lore.kernel.org/r/20210729043306.18528-1-mario.kleiner.de@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Oxford Semiconductor PCIe (Tornado) serial port devices are driven by a
fixed 62.5MHz clock input derived from the 100MHz PCI Express clock.
In the enhanced (650) mode, which we select in `autoconfig_has_efr' by
setting the ECB bit in the EFR register, and in the absence of clock
reconfiguration, which we currently don't do, the clock rate is divided
only by the oversampling rate of 16 as it is supplied to the baud rate
generator, yielding the baud base of 3906250. This comes from the reset
values of the TCR and MCR[7] registers which are both zero[1][2][3][4],
choosing the oversampling rate of 16 and the normal (divide by 1) baud
rate generator prescaler respectively. This is the rate that is divided
by the value held in the divisor latch to determine the baud rate used.
Replace the incorrect baud base of 4000000 with the right value of
3906250 then.
References:
[1] "OXPCIe200 PCI Express Multi-Port Bridge", Oxford Semiconductor,
Inc., DS-0045, 10 Nov 2008, Section "Reset Configuration", p. 72
[2] "OXPCIe952 PCI Express Bridge to Dual Serial & Parallel Port",
Oxford Semiconductor, Inc., DS-0046, Mar 06 08, Section "Reset
Configuration", p. 27
[3] "OXPCIe954 PCI Express Bridge to Quad Serial Port", Oxford
Semiconductor, Inc., DS-0047, Feb 08, Section "Reset Configuration",
p. 28
[4] "OXPCIe958 PCI Express Bridge to Octal Serial Port", Oxford
Semiconductor, Inc., DS-0048, Feb 08, Section "Reset Configuration",
p. 28
Fixes: 7106b4e333 ("8250: Oxford Semiconductor Devices")
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2106100203510.5469@angie.orcam.me.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Oxford Semiconductor PCIe (Tornado) serial port devices have their baud
base set incorrectly, however their `pciserial_board' entries have been
reused for Titan serial port devices. Define own entries for the latter
devices then, carrying over the settings, so that Oxford entries can be
fixed.
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2106100142310.5469@angie.orcam.me.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We need the tty/serial fixes in here and this resolves a merge issue in
the 8250 driver.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Link: https://lore.kernel.org/r/20200213004426.GA7886@embeddedor.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ioremap has provided non-cached semantics by default since the Linux 2.6
days, so remove the additional ioremap_nocache interface.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Pull tty/serial updates from Greg KH:
"Here is the "big" tty and serial driver patches for 5.5-rc1.
It's a bit later in the merge window than normal as I wanted to make
sure some last-minute patches applied to it were all sane. They seem
to be :)
There's a lot of little stuff in here, for the tty core, and for lots
of serial drivers:
- reverts of uartlite serial driver patches that were wrong
- msm-serial driver fixes
- serial core updates and fixes
- tty core fixes
- serial driver dma mapping api changes
- lots of other tiny fixes and updates for serial drivers
All of these have been in linux-next for a while with no reported
issues"
* tag 'tty-5.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (58 commits)
Revert "serial/8250: Add support for NI-Serial PXI/PXIe+485 devices"
vcs: prevent write access to vcsu devices
tty: vt: keyboard: reject invalid keycodes
tty: don't crash in tty_init_dev when missing tty_port
serial: stm32: fix clearing interrupt error flags
tty: Fix Kconfig indentation, continued
serial: serial_core: Perform NULL checks for break_ctl ops
tty: remove unused argument from tty_open_by_driver()
tty: Fix Kconfig indentation
{tty: serial, nand: onenand}: samsung: rename to fix build warning
serial: ifx6x60: add missed pm_runtime_disable
serial: pl011: Fix DMA ->flush_buffer()
Revert "serial-uartlite: Move the uart register"
Revert "serial-uartlite: Add get serial id if not provided"
Revert "serial-uartlite: Do not use static struct uart_driver out of probe()"
Revert "serial-uartlite: Add runtime support"
Revert "serial-uartlite: Change logic how console_port is setup"
Revert "serial-uartlite: Use allocated structure instead of static ones"
tty: serial: msm_serial: Use dma_request_chan() directly for channel request
tty: serial: tegra: Use dma_request_chan() directly for channel request
...
This reverts commit fdc2de8712 ("serial/8250:
Add support for NI-Serial PXI/PXIe+485 devices").
The commit fdc2de8712 ("serial/8250: Add support for NI-Serial
PXI/PXIe+485 devices") introduced a breakage on NI-Serial PXI(e)-RS485
devices, RS-232 variants have no issue. The Linux system can enumerate the
NI-Serial PXI(e)-RS485 devices, but it broke the R/W operation on the
ports.
However, the implementation is working on the NI internal Linux RT kernel
but it does not work in the Linux main tree kernel. This is only affecting
NI products, specifically the RS-485 variants. Reverting the upstream
until a proper implementation that can apply to both NI internal Linux
kernel and Linux mainline kernel is figured out.
Signed-off-by: Je Yen Tam <je.yen.tam@ni.com>
Fixes: fdc2de8712 ("serial/8250: Add support for NI-Serial PXI/PXIe+485 devices")
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20191127075301.9866-1-je.yen.tam@ni.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
There may be setups, where legacy interrupts are not available. This is
the caese, e.g., when Linux runs as guest (aka. non-root cell) of the
partitioning hypervisor Jailhouse. There, only MSI(-X) interrupts are
available for guests.
But the 8250_pci driver currently only supports legacy ints. So let's
enable MSI(-X) interrupts.
Nevertheless, this needs to handled with care: while many 8250 devices
actually claim to support MSI(-X) interrupts it should not be enabled be
default. I had at least one device in my hands with broken MSI
implementation.
So better introduce a whitelist with devices that are known to support
MSI(-X) interrupts. I tested all devices mentioned in the patch.
Signed-off-by: Ralf Ramsauer <ralf.ramsauer@oth-regensburg.de>
Link: https://lore.kernel.org/r/20190812112152.693622-1-ralf.ramsauer@oth-regensburg.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The Pericom chips can achieve additional baud rates by programming the
sample clock register. The baud rates can be described as
921600 * 16 / (16 - scr) for scr values 5 to 15. The divisor is set to 1
for these baud rates.
Adds new quirk for Pericom chips other than the four port chips to use
the
Signed-off-by: Jay Dolan <jay.dolan@accesio.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The four port Pericom chips have the fourth port at the wrong address.
Make use of quirk to fix it.
Fixes: c8d192428f ("serial: 8250: added acces i/o products quad and octal serial cards")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Jay Dolan <jay.dolan@accesio.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Have the correct number of ports created for ACCES serial cards. Two port
cards show up as four ports, and four port cards show up as eight.
Fixes: c8d192428f ("serial: 8250: added acces i/o products quad and octal serial cards")
Signed-off-by: Jay Dolan <jay.dolan@accesio.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
As has been reported the National Instruments serial cards have broken
PCI class.
The commit 7d8905d064
("serial: 8250_pci: Enable device after we check black list")
made the PCI class check mandatory for the case when device is listed in
a quirk list.
Make PCI class test non fatal to allow broken card be enumerated.
Fixes: 7d8905d064 ("serial: 8250_pci: Enable device after we check black list")
Cc: stable <stable@vger.kernel.org>
Reported-by: Guan Yung Tseng <guan.yung.tseng@ni.com>
Tested-by: Guan Yung Tseng <guan.yung.tseng@ni.com>
Tested-by: KHUENY.Gerhard <Gerhard.KHUENY@bachmann.info>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
After the commit
7d8905d064 ("serial: 8250_pci: Enable device after we check black list")
pure serial multi-port cards, such as CH355, got blacklisted and thus
not being enumerated anymore. Previously, it seems, blacklisting them
was on purpose to shut up pciserial_init_one() about record duplication.
So, remove the entries from blacklist in order to get cards enumerated.
Fixes: 7d8905d064 ("serial: 8250_pci: Enable device after we check black list")
Reported-by: Matt Turner <mattst88@gmail.com>
Cc: Sergej Pupykin <ml@sergej.pp.ru>
Cc: Alexandr Petrenko <petrenkoas83@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-and-Tested-by: Matt Turner <mattst88@gmail.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
