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linux_dsm_epyc7002/drivers/tty/serial/8250/Kconfig
Sebastian Andrzej Siewior 61929cf016 tty: serial: Add 8250-core based omap driver 
This patch provides a 8250-core based UART driver for the internal OMAP
UART. The long term goal is to provide the same functionality as the
current OMAP uart driver and DMA support.
I tried to merge omap-serial code together with the 8250-core code.
There should should be hardly a noticable difference. The trigger levels
are different compared to omap-serial:
- omap serial
  TX: Interrupt comes after TX FIFO has room for 16 bytes.
      TX of 4096 bytes in one go results in 256 interrupts

  RX: Interrupt comes after there is on byte in the FIFO.
      RX of 4096 bytes results in 4096 interrupts.

- this driver
  TX: Interrupt comes once the TX FIFO is empty.
      TX of 4096 bytes results in 65 interrupts. That means there will
      be gaps on the line while the driver reloads the FIFO.

  RX: Interrupt comes once there are 48 bytes in the FIFO or less over
      "longer" time frame. We have
          1 / 11520 * 10^3 * 16 => 1.38… ms
      1.38ms to react and purge the FIFO on 115200,8N1. Since the other
      driver fired after each byte it had ~5.47ms time to react. This
      _may_ cause problems if one relies on no missing bytes and has no
      flow control. On the other hand we get only 85 interrupts for the
      same amount of data.

It has been only tested as console UART on am335x-evm, dra7-evm and
beagle bone. I also did some longer raw-transfers to meassure the load.

The device name is ttyS based instead of ttyO. If a ttyO based node name
is required please ask udev for it. If both driver are activated (this
and omap-serial) then this serial driver will take control over the
device due to the link order

v9…v10:
	- Tony noticed that omap3 won't show anything after waking up
	  from core off. In v9 I reworked the register restore and set
	  IER to 0 by accident. This went unnoticed because start_tx
	  usually sets ier (either due to DMA bug or due to TX-complete
	  IRQ).
	- dropped EFR and SLEEP from capabilities. We do have both but
	  nobody should touch it. We already handle SLEEP ourself.
	- make the private copy of the registers (like EFR) u8 instead
	  u32
	- drop MDR1 & DL[ML] reset in restore registers. Does not look
	  required it is set to the required value later.
	- update MDR1 & SCR only if changed.
	- set MDR1 as the last thing. The errata says that we should
	  setup everything before MDR1 set.
	- avoid div by 0 in omap_8250_get_divisor() if baud rate gets
	  very large (Frans Klaver fixed the same thing omap-serial)
	- drop "is in early stage" from Kconfig.
v8…v9:
	- less on a file seems to hang the am335x after a while. I
	  believe I introduce this bug a while ago since I can reproduce
	  this prior to v8. Fixed by redoing the omap8250_restore_regs()
v7…v8:
	- redo the register write. There is now one function for that
	  which is used from set_termios() and runtime-resume.
	- drop PORT_OMAP_16750 and move the setup to the omap file. We
	  have our own set termios function anyway (Heikki Krogerus)
	- use MEM instead of MEM32. TRM of AM/DM37x says that 32bit
	  access on THR might result in data abort. We only need 32bit
	  access in the errata function which is before we use 8250's
	  read function so it doesn't matter.
v4…v7:
	- change trigger levels after some tests with raw transfers.
v3…v4:
	- drop RS485 support
	- wire up ->throttle / ->unthrottle
v2…v3:
	- wire up startup & shutdown for wakeup-irq handling.
	- RS485 handling (well the core does).

v1…v2:
	- added runtime PM. Could somebody could please double check
	  this?
	- added omap_8250_set_termios()

Reviewed-by: Tony Lindgren <tony@atomide.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Frans Klaver <frans.klaver@xsens.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05 19:05:13 -08:00

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#
# The 8250/16550 serial drivers. You shouldn't be in this list unless
# you somehow have an implicit or explicit dependency on SERIAL_8250.
#
config SERIAL_8250
tristate "8250/16550 and compatible serial support"
select SERIAL_CORE
---help---
This selects whether you want to include the driver for the standard
serial ports. The standard answer is Y. People who might say N
here are those that are setting up dedicated Ethernet WWW/FTP
servers, or users that have one of the various bus mice instead of a
serial mouse and don't intend to use their machine's standard serial
port for anything. (Note that the Cyclades multi serial port driver
does not need this driver built in for it to work.)
To compile this driver as a module, choose M here: the
module will be called 8250.
[WARNING: Do not compile this driver as a module if you are using
non-standard serial ports, since the configuration information will
be lost when the driver is unloaded. This limitation may be lifted
in the future.]
BTW1: If you have a mouseman serial mouse which is not recognized by
the X window system, try running gpm first.
BTW2: If you intend to use a software modem (also called Winmodem)
under Linux, forget it. These modems are crippled and require
proprietary drivers which are only available under Windows.
Most people will say Y or M here, so that they can use serial mice,
modems and similar devices connecting to the standard serial ports.
config SERIAL_8250_DEPRECATED_OPTIONS
bool "Support 8250_core.* kernel options (DEPRECATED)"
depends on SERIAL_8250
default y
---help---
In 3.7 we renamed 8250 to 8250_core by mistake, so now we have to
accept kernel parameters in both forms like 8250_core.nr_uarts=4 and
8250.nr_uarts=4. We now renamed the module back to 8250, but if
anybody noticed in 3.7 and changed their userspace we still have to
keep the 8250_core.* options around until they revert the changes
they already did.
If 8250 is built as a module, this adds 8250_core alias instead.
If you did not notice yet and/or you have userspace from pre-3.7, it
is safe (and recommended) to say N here.
config SERIAL_8250_PNP
bool "8250/16550 PNP device support" if EXPERT
depends on SERIAL_8250 && PNP
default y
---help---
This builds standard PNP serial support. You may be able to
disable this feature if you only need legacy serial support.
config SERIAL_8250_CONSOLE
bool "Console on 8250/16550 and compatible serial port"
depends on SERIAL_8250=y
select SERIAL_CORE_CONSOLE
select SERIAL_EARLYCON
---help---
If you say Y here, it will be possible to use a serial port as the
system console (the system console is the device which receives all
kernel messages and warnings and which allows logins in single user
mode). This could be useful if some terminal or printer is connected
to that serial port.
Even if you say Y here, the currently visible virtual console
(/dev/tty0) will still be used as the system console by default, but
you can alter that using a kernel command line option such as
"console=ttyS1". (Try "man bootparam" or see the documentation of
your boot loader (grub or lilo or loadlin) about how to pass options
to the kernel at boot time.)
If you don't have a VGA card installed and you say Y here, the
kernel will automatically use the first serial line, /dev/ttyS0, as
system console.
You can set that using a kernel command line option such as
"console=uart8250,io,0x3f8,9600n8"
"console=uart8250,mmio,0xff5e0000,115200n8".
and it will switch to normal serial console when the corresponding
port is ready.
"earlycon=uart8250,io,0x3f8,9600n8"
"earlycon=uart8250,mmio,0xff5e0000,115200n8".
it will not only setup early console.
If unsure, say N.
config SERIAL_8250_GSC
tristate
depends on SERIAL_8250 && GSC
default SERIAL_8250
config SERIAL_8250_DMA
bool "DMA support for 16550 compatible UART controllers" if EXPERT
depends on SERIAL_8250 && DMADEVICES=y
default SERIAL_8250
help
This builds DMA support that can be used with 8250/16650
compatible UART controllers that support DMA signaling.
config SERIAL_8250_PCI
tristate "8250/16550 PCI device support" if EXPERT
depends on SERIAL_8250 && PCI
default SERIAL_8250
help
This builds standard PCI serial support. You may be able to
disable this feature if you only need legacy serial support.
Saves about 9K.
Note that serial ports on NetMos 9835 Multi-I/O cards are handled
by the parport_serial driver, enabled with CONFIG_PARPORT_SERIAL.
config SERIAL_8250_HP300
tristate
depends on SERIAL_8250 && HP300
default SERIAL_8250
config SERIAL_8250_CS
tristate "8250/16550 PCMCIA device support"
depends on PCMCIA && SERIAL_8250
---help---
Say Y here to enable support for 16-bit PCMCIA serial devices,
including serial port cards, modems, and the modem functions of
multi-function Ethernet/modem cards. (PCMCIA- or PC-cards are
credit-card size devices often used with laptops.)
To compile this driver as a module, choose M here: the
module will be called serial_cs.
If unsure, say N.
config SERIAL_8250_NR_UARTS
int "Maximum number of 8250/16550 serial ports"
depends on SERIAL_8250
default "4"
help
Set this to the number of serial ports you want the driver
to support. This includes any ports discovered via ACPI or
PCI enumeration and any ports that may be added at run-time
via hot-plug, or any ISA multi-port serial cards.
config SERIAL_8250_RUNTIME_UARTS
int "Number of 8250/16550 serial ports to register at runtime"
depends on SERIAL_8250
range 0 SERIAL_8250_NR_UARTS
default "4"
help
Set this to the maximum number of serial ports you want
the kernel to register at boot time. This can be overridden
with the module parameter "nr_uarts", or boot-time parameter
8250.nr_uarts
config SERIAL_8250_EXTENDED
bool "Extended 8250/16550 serial driver options"
depends on SERIAL_8250
help
If you wish to use any non-standard features of the standard "dumb"
driver, say Y here. This includes HUB6 support, shared serial
interrupts, special multiport support, support for more than the
four COM 1/2/3/4 boards, etc.
Note that the answer to this question won't directly affect the
kernel: saying N will just cause the configurator to skip all
the questions about serial driver options. If unsure, say N.
config SERIAL_8250_MANY_PORTS
bool "Support more than 4 legacy serial ports"
depends on SERIAL_8250_EXTENDED && !IA64
help
Say Y here if you have dumb serial boards other than the four
standard COM 1/2/3/4 ports. This may happen if you have an AST
FourPort, Accent Async, Boca (read the Boca mini-HOWTO, available
from <http://www.tldp.org/docs.html#howto>), or other custom
serial port hardware which acts similar to standard serial port
hardware. If you only use the standard COM 1/2/3/4 ports, you can
say N here to save some memory. You can also say Y if you have an
"intelligent" multiport card such as Cyclades, Digiboards, etc.
#
# Multi-port serial cards
#
config SERIAL_8250_FOURPORT
tristate "Support Fourport cards"
depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
help
Say Y here if you have an AST FourPort serial board.
To compile this driver as a module, choose M here: the module
will be called 8250_fourport.
config SERIAL_8250_ACCENT
tristate "Support Accent cards"
depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
help
Say Y here if you have an Accent Async serial board.
To compile this driver as a module, choose M here: the module
will be called 8250_accent.
config SERIAL_8250_BOCA
tristate "Support Boca cards"
depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
help
Say Y here if you have a Boca serial board. Please read the Boca
mini-HOWTO, available from <http://www.tldp.org/docs.html#howto>
To compile this driver as a module, choose M here: the module
will be called 8250_boca.
config SERIAL_8250_EXAR_ST16C554
tristate "Support Exar ST16C554/554D Quad UART"
depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
help
The Uplogix Envoy TU301 uses this Exar Quad UART. If you are
tinkering with your Envoy TU301, or have a machine with this UART,
say Y here.
To compile this driver as a module, choose M here: the module
will be called 8250_exar_st16c554.
config SERIAL_8250_HUB6
tristate "Support Hub6 cards"
depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
help
Say Y here if you have a HUB6 serial board.
To compile this driver as a module, choose M here: the module
will be called 8250_hub6.
#
# Misc. options/drivers.
#
config SERIAL_8250_SHARE_IRQ
bool "Support for sharing serial interrupts"
depends on SERIAL_8250_EXTENDED
help
Some serial boards have hardware support which allows multiple dumb
serial ports on the same board to share a single IRQ. To enable
support for this in the serial driver, say Y here.
config SERIAL_8250_DETECT_IRQ
bool "Autodetect IRQ on standard ports (unsafe)"
depends on SERIAL_8250_EXTENDED
help
Say Y here if you want the kernel to try to guess which IRQ
to use for your serial port.
This is considered unsafe; it is far better to configure the IRQ in
a boot script using the setserial command.
If unsure, say N.
config SERIAL_8250_RSA
bool "Support RSA serial ports"
depends on SERIAL_8250_EXTENDED
help
::: To be written :::
config SERIAL_8250_ACORN
tristate "Acorn expansion card serial port support"
depends on ARCH_ACORN && SERIAL_8250
help
If you have an Atomwide Serial card or Serial Port card for an Acorn
system, say Y to this option. The driver can handle 1, 2, or 3 port
cards. If unsure, say N.
config SERIAL_8250_FSL
bool
depends on SERIAL_8250_CONSOLE && PPC_UDBG_16550
default PPC
config SERIAL_8250_DW
tristate "Support for Synopsys DesignWare 8250 quirks"
depends on SERIAL_8250
help
Selecting this option will enable handling of the extra features
present in the Synopsys DesignWare APB UART.
config SERIAL_8250_EM
tristate "Support for Emma Mobile integrated serial port"
depends on SERIAL_8250 && ARM && HAVE_CLK
help
Selecting this option will add support for the integrated serial
port hardware found on the Emma Mobile line of processors.
If unsure, say N.
config SERIAL_8250_RT288X
bool "Ralink RT288x/RT305x/RT3662/RT3883 serial port support"
depends on SERIAL_8250 && (SOC_RT288X || SOC_RT305X || SOC_RT3883)
help
If you have a Ralink RT288x/RT305x SoC based board and want to use the
serial port, say Y to this option. The driver can handle up to 2 serial
ports. If unsure, say N.
config SERIAL_8250_OMAP
tristate "Support for OMAP internal UART (8250 based driver)"
depends on SERIAL_8250 && ARCH_OMAP2PLUS
help
If you have a machine based on an Texas Instruments OMAP CPU you
can enable its onboard serial ports by enabling this option.
This driver uses ttyS instead of ttyO.
config SERIAL_8250_FINTEK
tristate "Support for Fintek F81216A LPC to 4 UART"
depends on SERIAL_8250 && PNP
help
Selecting this option will add support for the Fintek F81216A
LPC to 4 UART. This device has some RS485 functionality not available
through the PNP driver. If unsure, say N.
config SERIAL_8250_MT6577
bool "Mediatek serial port support"
depends on SERIAL_8250 && ARCH_MEDIATEK
help
If you have a Mediatek based board and want to use the
serial port, say Y to this option. If unsure, say N.
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