linux-toradex.git/include/uapi/linux/serial_reg.h, branch v5.17-rc5

serial: 8250: Define RX trigger levels for OxSemi 950 devices

2021-07-27T10:05:46+00:00

Oxford Semiconductor 950 serial port devices have a 128-byte FIFO and in
the enhanced (650) mode, which we select in `autoconfig_has_efr' with
the ECB bit set in the EFR register, they support the receive interrupt
trigger level selectable with FCR bits 7:6 from the set of 16, 32, 112,
120.  This applies to the original OX16C950 discrete UART[1] as well as
950 cores embedded into more complex devices.

For these devices we set the default to 112, which sets an excessively
high level of 112 or 7/8 of the FIFO capacity, unlike with other port
types where we choose at most 1/2 of their respective FIFO capacities.
Additionally we don't make the trigger level configurable.  Consequently
frequent input overruns happen with high bit rates where hardware flow
control cannot be used (e.g. terminal applications) even with otherwise
highly-performant systems.

Lower the default receive interrupt trigger level to 32 then, and make
it configurable.  Document the trigger levels along with other port
types, including the set of 16, 32, 64, 112 for the transmit interrupt
as well[2].

References:

[1] "OX16C950 rev B High Performance UART with 128 byte FIFOs", Oxford
    Semiconductor, Inc., DS-0031, Sep 05, Table 10: "Receiver Trigger
    Levels", p. 22

[2] same, Table 9: "Transmit Interrupt Trigger Levels", p. 22

Signed-off-by: Maciej W. Rozycki 
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2106260608480.37803@angie.orcam.me.uk
Signed-off-by: Greg Kroah-Hartman

Merge tag 'tty-4.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

2017-11-14T05:05:31+00:00

Pull tty/serial updates from Greg KH:
 "Here is the big tty/serial driver pull request for 4.15-rc1.

  Lots of serial driver updates in here, some small vt cleanups, and a
  raft of SPDX and license boilerplate cleanups, messing up the diffstat
  a bit.

  Nothing major, with no realy functional changes except better hardware
  support for some platforms.

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'tty-4.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (110 commits)
  tty: ehv_bytechan: fix spelling mistake
  tty: serial: meson: allow baud-rates lower than 9600
  serial: 8250_fintek: Fix crash with baud rate B0
  serial: 8250_fintek: Disable delays for ports != 0
  serial: 8250_fintek: Return -EINVAL on invalid configuration
  tty: Remove redundant license text
  tty: serdev: Remove redundant license text
  tty: hvc: Remove redundant license text
  tty: serial: Remove redundant license text
  tty: add SPDX identifiers to all remaining files in drivers/tty/
  tty: serial: jsm: remove redundant pointer ts
  tty: serial: jsm: add space before the open parenthesis '('
  tty: serial: jsm: fix coding style
  tty: serial: jsm: delete space between function name and '('
  tty: serial: jsm: add blank line after declarations
  tty: serial: jsm: change the type of local variable
  tty: serial: imx: remove dead code imx_dma_rxint
  tty: serial: imx: disable ageing timer interrupt if dma in use
  serial: 8250: fix potential deadlock in rs485-mode
  serial: m32r_sio: Drop redundant .data assignment
  ...

License cleanup: add SPDX license identifier to uapi header files with a license

2017-11-02T10:20:11+00:00

Many user space API headers have licensing information, which is either
incomplete, badly formatted or just a shorthand for referring to the
license under which the file is supposed to be.  This makes it hard for
compliance tools to determine the correct license.

Update these files with an SPDX license identifier.  The identifier was
chosen based on the license information in the file.

GPL/LGPL licensed headers get the matching GPL/LGPL SPDX license
identifier with the added 'WITH Linux-syscall-note' exception, which is
the officially assigned exception identifier for the kernel syscall
exception:

   NOTE! This copyright does *not* cover user programs that use kernel
   services by normal system calls - this is merely considered normal use
   of the kernel, and does *not* fall under the heading of "derived work".

This exception makes it possible to include GPL headers into non GPL
code, without confusing license compliance tools.

Headers which have either explicit dual licensing or are just licensed
under a non GPL license are updated with the corresponding SPDX
identifier and the GPLv2 with syscall exception identifier.  The format
is:
        ((GPL-2.0 WITH Linux-syscall-note) OR SPDX-ID-OF-OTHER-LICENSE)

SPDX license identifiers are a legally binding shorthand, which can be
used instead of the full boiler plate text.  The update does not remove
existing license information as this has to be done on a case by case
basis and the copyright holders might have to be consulted. This will
happen in a separate step.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.  See the previous patch in this series for the
methodology of how this patch was researched.

Reviewed-by: Kate Stewart 
Reviewed-by: Philippe Ombredanne 
Reviewed-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

serial: Add define for max baud rate divisor

2017-10-04T08:17:27+00:00

Add a define for the maximum baud rate divisor, to improve code
readability.

Signed-off-by: Ed Blake 
Signed-off-by: Greg Kroah-Hartman

serial: exar: Move register defines from uapi header to consumer site

2017-02-10T14:13:26+00:00

None of these registers is relevant for the userspace API.

Signed-off-by: Jan Kiszka 
Signed-off-by: Greg Kroah-Hartman

serial: exar: Fix feature control register constants

2017-02-10T14:12:38+00:00

According to the XR17V352 manual, bit 4 is IrDA control and bit 5 for
485. Fortunately, no driver used them so far.

Signed-off-by: Jan Kiszka 
Reviewed-by: Andy Shevchenko 
Signed-off-by: Greg Kroah-Hartman

serial: 8250: Add new port type for TI DA8xx/66AK2x

2017-01-12T10:51:25+00:00

This adds a new UART port type for TI DA8xx/OMAPL13x/AM17xx/AM18xx/66AK2x.
These SoCs have standard 8250 registers plus some extra non-standard
registers.

The UART will not function unless the non-standard Power and Emulation
Management Register (PWREMU_MGMT) is configured correctly. This is
currently handled in arch/arm/mach-davinci/serial.c for non-device-tree
boards. Making this part of the UART driver will allow UART to work on
device-tree boards as well and the mach code can eventually be removed.

Signed-off-by: David Lechner 
Acked-by: Sekhar Nori 
Signed-off-by: Greg Kroah-Hartman

serial: 8250: Set Altera 16550 TX FIFO Threshold

2016-09-27T10:55:50+00:00

The Altera 16550 soft IP UART requires 2 additional registers for
TX FIFO threshold support. These 2 registers enable the TX FIFO
Low Watermark and set the TX FIFO Low Watermark.
Set the TX FIFO threshold to the FIFO size - tx_loadsz.

Signed-off-by: Thor Thayer 
Signed-off-by: Greg Kroah-Hartman

ARM: OMAP1: Move UART defines to prepare for sparse IRQ

2015-05-20T16:01:20+00:00

These have been indirectly included via asm/irqs.h that
has included mach/hardware.h unless SPARSE_IRQ is specified.
Let's move them to where the other OMAP serial defines for
8250 are.

Cc: Aaro Koskinen 
Cc: Greg Kroah-Hartman 
Signed-off-by: Tony Lindgren

x86, intel-mid: remove Intel MID specific serial support

2015-03-07T02:25:18+00:00

Since we have a native 8250 driver carrying the Intel MID serial devices the
specific support is not needed anymore. This patch removes it for Intel MID.

Note that the console device name is changed from ttyMFDx to ttySx.

Signed-off-by: Andy Shevchenko 
Acked-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman