devc-*, devc-ser* options

Description:

All serial character drivers support the generic options described below.

devc-* generic options (Apply for all devc-*)

-C number

The size of the canonical buffer in bytes (default 256).

-E

Set options to raw (this is the default). Software flow control is disabled by default.

When set in raw mode, the following terminal flags are initialized:

c_cflag = CREAD | CS8 | IHFLOW | OHFLOW | HUPCL;
c_iflag = IMAXBEL | INPCK;
c_lflag = 0;
c_oflag = ONLCR;

The order in which you specify the -E, and -S or -s options matters:

Options	Mode	Software flow control
-E	Raw	Disabled
-s -E	Raw	Disabled
-E -s	Raw	Enabled

You can set individual terminal flags to supplement raw mode, through the -o termflags option.

-e

Start in edited mode (the default is raw). Software flow control is enabled by default.

When set in edited mode, the following terminal flags are initialized:

c_cflag = CREAD | CS8 | HUPCL;
c_iflag = IMAXBEL | INPCK | BRKINT | ICRNL | IXON | IXOFF;
c_lflag = ECHO | ECHOCTL | ECHOE | ECHOKE | ICANON | ISIG | IEXTEN;
c_oflag = ONLCR | OPOST;

The order in which you specify the -e, and -S or -s options matters:

Options	Mode	Software flow control
-e	Edited	Enabled
-S -e	Edited	Enabled
-e -S	Edited	Disabled

You can set individual terminal flags to supplement edited mode, through the -o termflags option.

-F

Disable hardware flow control. The default depends on the mode:

• in raw mode (-E), it's enabled (-f)
• in edited mode (-e), it's disabled (-F)

Hardware flow control isn't supported in edited mode.

-f

Enable hardware flow control. The default depends on the mode:

• in raw mode (-E), it's enabled (-f)
• in edited mode (-e), it's disabled (-F)

Hardware flow control isn't supported in edited mode.

-I number

The size of the raw input buffer in bytes. The default is 2048.

-O number

(Oh) The size of the output buffer in bytes. The default is 2048.

-o opt[,opt...]

Additional options, separated by commas. The options include:

• devperm — Set permissions to the serial device.
• disable=rx — Disable the UART receiver on driver startup.
• highwater=value — Set the receive highwater mark for input flow control. This specifies when to assert input flow control based on the byte level in ibuf.
• kdebug — Enable kernal tracing of events on the system.
• log=flow[@directory_path]—Specify whether to log data for receive, transmit, or both. If directory_path isn't specified, the default log directory is /dev/shmem. Specify one of these values for flow:
  • tx — transmit data only
  • rx — receive data only
  • all — both transmit and receive
• nodaemon — Don't call procmgr_daemon() to make the driver run in the background. Use this option if you need to know when the device terminates.
• priority=prio — Set the working priority of the internal pulse as a numeric value.
• smmu=0|1|off|on — Specify whether or not support for the system memory management unit (IOMMU/SMMU) manager is required:
  • 0 or off — disable SMMU support. This is the default.
  • 1 or on — SMMU support is required; the driver exits if it isn't available

  For more information, see the SMMUMAN User's Guide.

• termflags=[-]flag[:[-]flag]* — Specify terminal flag settings. This option should be used to supplement the raw or edited mode by setting (enabling) and/or clearing (disabling) individual terminal flags that were initialized by -E or -e. Because the driver options are processed in the order in which they appear, the -o termflags option must be provided after other options that affect terminal flags. This is to ensure that other options don't negate the effects of this option.

  If you put a dash (-) in front of a flag's name, the flag is disabled; no dash means the flag is enabled.

  For input modes, the supported flag values are:

  • brkint
  • icrnl
  • ignbrk
  • igncr
  • ignpar
  • inlcr
  • inpcl
  • istrip
  • ixoff
  • ixon
  • parmrk
  For output modes, you can specify these flag values:

  • opost
  For control modes, you can specify these flag values:

  • clocal
  • cread
  • csize
  • cs5
  • cs6
  • cs7
  • cs8
  • cstopb
  • hupcl
  • ihflow
  • ohflow
  • parenb
  • parodd
  • parstk
  For local modes, you can specify these flag values:

  • echo
  • echoe
  • echok
  • echonl
  • icanon
  • iexten
  • isig
  • noflsh
  • tostop

  For the meanings of these flags, see the c_iflag, c_oflag, c_cflag, and c_lflag descriptions in the termios entry in the C Library Reference.

• ticksize_ms=value — Timer granularity in microseconds (default 50ms).

-S

Disable software flow control. The default depends on the mode:

• in raw mode (-E), it's disabled (-S)
• in edited mode (-e), it's enabled (-s)

-s

Enable software flow control. The default depends on the mode:

• in raw mode (-E), it's disabled (-S)
• in edited mode (-e), it's enabled (-s)

-v[v]...

Be verbose; additional v characters cause more verbosity.

devc-ser* generic options (Apply for all devc-ser* and devc-virtio only)

-b number

Set the baud rates. The supported baud rates depend on the board that the driver is running on. The default baud rate is 57600.

-c clock[/divisor]

Set a custom clock rate, in Hertz, and a divisor for the serial port. The default (-c 1843200/16) is suitable for compatible PC serial ports.

-u unit

Set the serial unit number (default 1).