linux/drivers/tty/hvc/Kconfig

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# SPDX-License-Identifier: GPL-2.0
config HVC_DRIVER
bool
help
Generic "hypervisor virtual console" infrastructure for various
hypervisors (pSeries, iSeries, Xen).
It will automatically be selected if one of the back-end console drivers
is selected.
config HVC_IRQ
bool
config HVC_CONSOLE
bool "pSeries Hypervisor Virtual Console support"
depends on PPC_PSERIES
select HVC_DRIVER
select HVC_IRQ
help
pSeries machines when partitioned support a hypervisor virtual
console. This driver allows each pSeries partition to have a console
which is accessed via the HMC.
powerpc/pseries: Re-implement HVSI as part of hvc_vio On pseries machines, consoles are provided by the hypervisor using a low level get_chars/put_chars type interface. However, this is really just a transport to the service processor which implements them either as "raw" console (networked consoles, HMC, ...) or as "hvsi" serial ports. The later is a simple packet protocol on top of the raw character interface that is supposed to convey additional "serial port" style semantics. In practice however, all it does is provide a way to read the CD line and set/clear our DTR line, that's it. We currently implement the "raw" protocol as an hvc console backend (/dev/hvcN) and the "hvsi" protocol using a separate tty driver (/dev/hvsi0). However this is quite impractical. The arbitrary difference between the two type of devices has been a major source of user (and distro) confusion. Additionally, there's an additional mini -hvsi implementation in the pseries platform code for our low level debug console and early boot kernel messages, which means code duplication, though that low level variant is impractical as it's incapable of doing the initial protocol negociation to establish the link to the FSP. This essentially replaces the dedicated hvsi driver and the platform udbg code completely by extending the existing hvc_vio backend used in "raw" mode so that: - It now supports HVSI as well - We add support for hvc backend providing tiocm{get,set} - It also provides a udbg interface for early debug and boot console This is overall less code, though this will only be obvious once we remove the old "hvsi" driver, which is still available for now. When the old driver is enabled, the new code still kicks in for the low level udbg console, replacing the old mini implementation in the platform code, it just doesn't provide the higher level "hvc" interface. In addition to producing generally simler code, this has several benefits over our current situation: - The user/distro only has to deal with /dev/hvcN for the hypervisor console, avoiding all sort of confusion that has plagued us in the past - The tty, kernel and low level debug console all use the same code base which supports the full protocol establishment process, thus the console is now available much earlier than it used to be with the old HVSI driver. The kernel console works much earlier and udbg is available much earlier too. Hackers can enable a hard coded very-early debug console as well that works with HVSI (previously that was only supported for the "raw" mode). I've tried to keep the same semantics as hvsi relative to how I react to things like CD changes, with some subtle differences though: - I clear DTR on close if HUPCL is set - Current hvsi triggers a hangup if it detects a up->down transition on CD (you can still open a console with CD down). My new implementation triggers a hangup if the link to the FSP is severed, and severs it upon detecting a up->down transition on CD. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-05-12 03:46:38 +00:00
config HVC_OLD_HVSI
bool "Old driver for pSeries serial port (/dev/hvsi*)"
depends on HVC_CONSOLE
config HVC_OPAL
bool "OPAL Console support"
depends on PPC_POWERNV
select HVC_DRIVER
select HVC_IRQ
default y
help
PowerNV machines running under OPAL need that driver to get a console
config HVC_RTAS
bool "IBM RTAS Console support"
depends on PPC_RTAS
select HVC_DRIVER
help
IBM Console device driver which makes use of RTAS
config HVC_IUCV
bool "z/VM IUCV Hypervisor console support (VM only)"
depends on S390 && NET
select HVC_DRIVER
select IUCV
default y
help
This driver provides a Hypervisor console (HVC) back-end to access
a Linux (console) terminal via a z/VM IUCV communication path.
config HVC_XEN
bool "Xen Hypervisor Console support"
depends on XEN
select HVC_DRIVER
select HVC_IRQ
default y
help
Xen virtual console device driver
config HVC_XEN_FRONTEND
bool "Xen Hypervisor Multiple Consoles support"
depends on HVC_XEN
select XEN_XENBUS_FRONTEND
default y
help
Xen driver for secondary virtual consoles
config HVC_UDBG
bool "udbg based fake hypervisor console"
depends on PPC
select HVC_DRIVER
help
This is meant to be used during HW bring up or debugging when
no other console mechanism exist but udbg, to get you a quick
console for userspace. Do NOT enable in production kernels.
config HVC_DCC
bool "ARM JTAG DCC console"
depends on ARM || ARM64
select HVC_DRIVER
select SERIAL_CORE_CONSOLE
help
This console uses the JTAG DCC on ARM to create a console under the HVC
driver. This console is used through a JTAG only on ARM. If you don't have
a JTAG then you probably don't want this option.
config HVC_RISCV_SBI
bool "RISC-V SBI console support"
depends on RISCV_SBI_V01
select HVC_DRIVER
help
This enables support for console output via RISC-V SBI calls, which
is normally used only during boot to output printk.
If you don't know what do to here, say Y.
config HVCS
tristate "IBM Hypervisor Virtual Console Server support"
depends on PPC_PSERIES && HVC_CONSOLE
help
Partitionable IBM Power5 ppc64 machines allow hosting of
firmware virtual consoles from one Linux partition by
another Linux partition. This driver allows console data
from Linux partitions to be accessed through TTY device
interfaces in the device tree of a Linux partition running
this driver.
To compile this driver as a module, choose M here: the
module will be called hvcs. Additionally, this module
will depend on arch specific APIs exported from hvcserver.ko
which will also be compiled when this driver is built as a
module.