diff options
| author | Timur Tabi <timur@freescale.com> | 2011-07-09 04:06:12 +0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-08-23 21:32:56 +0400 |
| commit | dcd83aaff1c8cbd5b48c152b559e0af3ea1a7b65 (patch) | |
| tree | 536ce3416fd908f0506899b371d86fb21171078c /drivers/tty/Kconfig | |
| parent | fcb8ce5cfe30ca9ca5c9a79cdfe26d1993e65e0c (diff) | |
| download | linux-dcd83aaff1c8cbd5b48c152b559e0af3ea1a7b65.tar.xz | |
tty/powerpc: introduce the ePAPR embedded hypervisor byte channel driver
The ePAPR embedded hypervisor specification provides an API for "byte
channels", which are serial-like virtual devices for sending and receiving
streams of bytes. This driver provides Linux kernel support for byte
channels via three distinct interfaces:
1) An early-console (udbg) driver. This provides early console output
through a byte channel. The byte channel handle must be specified in a
Kconfig option.
2) A normal console driver. Output is sent to the byte channel designated
for stdout in the device tree. The console driver is for handling kernel
printk calls.
3) A tty driver, which is used to handle user-space input and output. The
byte channel used for the console is designated as the default tty.
Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/tty/Kconfig')
| -rw-r--r-- | drivers/tty/Kconfig | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig index bd7cc0527999..f1ea59b09444 100644 --- a/drivers/tty/Kconfig +++ b/drivers/tty/Kconfig @@ -350,3 +350,37 @@ config TRACE_SINK If you select this option, you need to select "Trace data router for MIPI P1149.7 cJTAG standard". + +config PPC_EPAPR_HV_BYTECHAN + tristate "ePAPR hypervisor byte channel driver" + depends on PPC + help + This driver creates /dev entries for each ePAPR hypervisor byte + channel, thereby allowing applications to communicate with byte + channels as if they were serial ports. + +config PPC_EARLY_DEBUG_EHV_BC + bool "Early console (udbg) support for ePAPR hypervisors" + depends on PPC_EPAPR_HV_BYTECHAN + help + Select this option to enable early console (a.k.a. "udbg") support + via an ePAPR byte channel. You also need to choose the byte channel + handle below. + +config PPC_EARLY_DEBUG_EHV_BC_HANDLE + int "Byte channel handle for early console (udbg)" + depends on PPC_EARLY_DEBUG_EHV_BC + default 0 + help + If you want early console (udbg) output through a byte channel, + specify the handle of the byte channel to use. + + For this to work, the byte channel driver must be compiled + in-kernel, not as a module. + + Note that only one early console driver can be enabled, so don't + enable any others if you enable this one. + + If the number you specify is not a valid byte channel handle, then + there simply will be no early console output. This is true also + if you don't boot under a hypervisor at all. |