17 Mar, 2020
1 commit
-
ev_byte_channel_send() assumes that its third argument is a 16 byte
array. Some places where it is called it may not be (or we can't
easily tell if it is). Newer compilers have started producing warnings
about this, so make sure we actually pass a 16 byte array.There may be more elegant solutions to this, but the driver is quite
old and hasn't been updated in many years.The warnings (from a powerpc allyesconfig build) are:
In file included from include/linux/byteorder/big_endian.h:5,
from arch/powerpc/include/uapi/asm/byteorder.h:14,
from include/asm-generic/bitops/le.h:6,
from arch/powerpc/include/asm/bitops.h:250,
from include/linux/bitops.h:29,
from include/linux/kernel.h:12,
from include/asm-generic/bug.h:19,
from arch/powerpc/include/asm/bug.h:109,
from include/linux/bug.h:5,
from include/linux/mmdebug.h:5,
from include/linux/gfp.h:5,
from include/linux/slab.h:15,
from drivers/tty/ehv_bytechan.c:24:
drivers/tty/ehv_bytechan.c: In function ‘ehv_bc_udbg_putc’:
arch/powerpc/include/asm/epapr_hcalls.h:298:20: warning: array subscript 1 is outside array bounds of ‘const char[1]’ [-Warray-bounds]
298 | r6 = be32_to_cpu(p[1]);
include/uapi/linux/byteorder/big_endian.h:40:51: note: in definition of macro ‘__be32_to_cpu’
40 | #define __be32_to_cpu(x) ((__force __u32)(__be32)(x))
| ^
arch/powerpc/include/asm/epapr_hcalls.h:298:7: note: in expansion of macro ‘be32_to_cpu’
298 | r6 = be32_to_cpu(p[1]);
| ^~~~~~~~~~~
drivers/tty/ehv_bytechan.c:166:13: note: while referencing ‘data’
166 | static void ehv_bc_udbg_putc(char c)
| ^~~~~~~~~~~~~~~~Fixes: dcd83aaff1c8 ("tty/powerpc: introduce the ePAPR embedded hypervisor byte channel driver")
Signed-off-by: Stephen Rothwell
Tested-by: Laurentiu Tudor
[mpe: Trim warnings from change log]
Signed-off-by: Michael Ellerman
Link: https://lore.kernel.org/r/20200109183912.5fcb52aa@canb.auug.org.au
18 Sep, 2018
1 commit
-
In preparation to remove the node name pointer from struct device_node,
convert printf users to use the %pOFn format specifier.Cc: Greg Kroah-Hartman
Cc: Jiri Slaby
Cc: Benjamin Herrenschmidt
Cc: Paul Mackerras
Cc: Michael Ellerman
Cc: linux-serial@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Rob Herring
Signed-off-by: Greg Kroah-Hartman
13 Jun, 2018
1 commit
-
The kzalloc() function has a 2-factor argument form, kcalloc(). This
patch replaces cases of:kzalloc(a * b, gfp)
with:
kcalloc(a * b, gfp)as well as handling cases of:
kzalloc(a * b * c, gfp)
with:
kzalloc(array3_size(a, b, c), gfp)
as it's slightly less ugly than:
kzalloc_array(array_size(a, b), c, gfp)
This does, however, attempt to ignore constant size factors like:
kzalloc(4 * 1024, gfp)
though any constants defined via macros get caught up in the conversion.
Any factors with a sizeof() of "unsigned char", "char", and "u8" were
dropped, since they're redundant.The Coccinelle script used for this was:
// Fix redundant parens around sizeof().
@@
type TYPE;
expression THING, E;
@@(
kzalloc(
- (sizeof(TYPE)) * E
+ sizeof(TYPE) * E
, ...)
|
kzalloc(
- (sizeof(THING)) * E
+ sizeof(THING) * E
, ...)
)// Drop single-byte sizes and redundant parens.
@@
expression COUNT;
typedef u8;
typedef __u8;
@@(
kzalloc(
- sizeof(u8) * (COUNT)
+ COUNT
, ...)
|
kzalloc(
- sizeof(__u8) * (COUNT)
+ COUNT
, ...)
|
kzalloc(
- sizeof(char) * (COUNT)
+ COUNT
, ...)
|
kzalloc(
- sizeof(unsigned char) * (COUNT)
+ COUNT
, ...)
|
kzalloc(
- sizeof(u8) * COUNT
+ COUNT
, ...)
|
kzalloc(
- sizeof(__u8) * COUNT
+ COUNT
, ...)
|
kzalloc(
- sizeof(char) * COUNT
+ COUNT
, ...)
|
kzalloc(
- sizeof(unsigned char) * COUNT
+ COUNT
, ...)
)// 2-factor product with sizeof(type/expression) and identifier or constant.
@@
type TYPE;
expression THING;
identifier COUNT_ID;
constant COUNT_CONST;
@@(
- kzalloc
+ kcalloc
(
- sizeof(TYPE) * (COUNT_ID)
+ COUNT_ID, sizeof(TYPE)
, ...)
|
- kzalloc
+ kcalloc
(
- sizeof(TYPE) * COUNT_ID
+ COUNT_ID, sizeof(TYPE)
, ...)
|
- kzalloc
+ kcalloc
(
- sizeof(TYPE) * (COUNT_CONST)
+ COUNT_CONST, sizeof(TYPE)
, ...)
|
- kzalloc
+ kcalloc
(
- sizeof(TYPE) * COUNT_CONST
+ COUNT_CONST, sizeof(TYPE)
, ...)
|
- kzalloc
+ kcalloc
(
- sizeof(THING) * (COUNT_ID)
+ COUNT_ID, sizeof(THING)
, ...)
|
- kzalloc
+ kcalloc
(
- sizeof(THING) * COUNT_ID
+ COUNT_ID, sizeof(THING)
, ...)
|
- kzalloc
+ kcalloc
(
- sizeof(THING) * (COUNT_CONST)
+ COUNT_CONST, sizeof(THING)
, ...)
|
- kzalloc
+ kcalloc
(
- sizeof(THING) * COUNT_CONST
+ COUNT_CONST, sizeof(THING)
, ...)
)// 2-factor product, only identifiers.
@@
identifier SIZE, COUNT;
@@- kzalloc
+ kcalloc
(
- SIZE * COUNT
+ COUNT, SIZE
, ...)// 3-factor product with 1 sizeof(type) or sizeof(expression), with
// redundant parens removed.
@@
expression THING;
identifier STRIDE, COUNT;
type TYPE;
@@(
kzalloc(
- sizeof(TYPE) * (COUNT) * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
kzalloc(
- sizeof(TYPE) * (COUNT) * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
kzalloc(
- sizeof(TYPE) * COUNT * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
kzalloc(
- sizeof(TYPE) * COUNT * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
kzalloc(
- sizeof(THING) * (COUNT) * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
|
kzalloc(
- sizeof(THING) * (COUNT) * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
|
kzalloc(
- sizeof(THING) * COUNT * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
|
kzalloc(
- sizeof(THING) * COUNT * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
)// 3-factor product with 2 sizeof(variable), with redundant parens removed.
@@
expression THING1, THING2;
identifier COUNT;
type TYPE1, TYPE2;
@@(
kzalloc(
- sizeof(TYPE1) * sizeof(TYPE2) * COUNT
+ array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
, ...)
|
kzalloc(
- sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+ array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
, ...)
|
kzalloc(
- sizeof(THING1) * sizeof(THING2) * COUNT
+ array3_size(COUNT, sizeof(THING1), sizeof(THING2))
, ...)
|
kzalloc(
- sizeof(THING1) * sizeof(THING2) * (COUNT)
+ array3_size(COUNT, sizeof(THING1), sizeof(THING2))
, ...)
|
kzalloc(
- sizeof(TYPE1) * sizeof(THING2) * COUNT
+ array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
, ...)
|
kzalloc(
- sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+ array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
, ...)
)// 3-factor product, only identifiers, with redundant parens removed.
@@
identifier STRIDE, SIZE, COUNT;
@@(
kzalloc(
- (COUNT) * STRIDE * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kzalloc(
- COUNT * (STRIDE) * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kzalloc(
- COUNT * STRIDE * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kzalloc(
- (COUNT) * (STRIDE) * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kzalloc(
- COUNT * (STRIDE) * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kzalloc(
- (COUNT) * STRIDE * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kzalloc(
- (COUNT) * (STRIDE) * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
kzalloc(
- COUNT * STRIDE * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
)// Any remaining multi-factor products, first at least 3-factor products,
// when they're not all constants...
@@
expression E1, E2, E3;
constant C1, C2, C3;
@@(
kzalloc(C1 * C2 * C3, ...)
|
kzalloc(
- (E1) * E2 * E3
+ array3_size(E1, E2, E3)
, ...)
|
kzalloc(
- (E1) * (E2) * E3
+ array3_size(E1, E2, E3)
, ...)
|
kzalloc(
- (E1) * (E2) * (E3)
+ array3_size(E1, E2, E3)
, ...)
|
kzalloc(
- E1 * E2 * E3
+ array3_size(E1, E2, E3)
, ...)
)// And then all remaining 2 factors products when they're not all constants,
// keeping sizeof() as the second factor argument.
@@
expression THING, E1, E2;
type TYPE;
constant C1, C2, C3;
@@(
kzalloc(sizeof(THING) * C2, ...)
|
kzalloc(sizeof(TYPE) * C2, ...)
|
kzalloc(C1 * C2 * C3, ...)
|
kzalloc(C1 * C2, ...)
|
- kzalloc
+ kcalloc
(
- sizeof(TYPE) * (E2)
+ E2, sizeof(TYPE)
, ...)
|
- kzalloc
+ kcalloc
(
- sizeof(TYPE) * E2
+ E2, sizeof(TYPE)
, ...)
|
- kzalloc
+ kcalloc
(
- sizeof(THING) * (E2)
+ E2, sizeof(THING)
, ...)
|
- kzalloc
+ kcalloc
(
- sizeof(THING) * E2
+ E2, sizeof(THING)
, ...)
|
- kzalloc
+ kcalloc
(
- (E1) * E2
+ E1, E2
, ...)
|
- kzalloc
+ kcalloc
(
- (E1) * (E2)
+ E1, E2
, ...)
|
- kzalloc
+ kcalloc
(
- E1 * E2
+ E1, E2
, ...)
)Signed-off-by: Kees Cook
08 Nov, 2017
3 commits
-
Trivial fix to spelling mistakes "interupt" -> "interrupt".
Signed-off-by: Arvind Yadav
Signed-off-by: Greg Kroah-Hartman -
Now that the SPDX tag is in all tty files, that identifies the license
in a specific and legally-defined manner. So the extra GPL text wording
can be removed as it is no longer needed at all.This is done on a quest to remove the 700+ different ways that files in
the kernel describe the GPL license text. And there's unneeded stuff
like the address (sometimes incorrect) for the FSF which is never
needed.No copyright headers or other non-license-description text was removed.
Cc: Jiri Slaby
Cc: James Hogan
Signed-off-by: Greg Kroah-Hartman -
It's good to have SPDX identifiers in all files to make it easier to
audit the kernel tree for correct licenses.Update the drivers/tty files files with the correct SPDX license
identifier based on the license text in the file itself. The SPDX
identifier is a legally binding shorthand, which can be used instead of
the full boiler plate text.This work is based on a script and data from Thomas Gleixner, Philippe
Ombredanne, and Kate Stewart.Cc: Jiri Slaby
Cc: Benjamin Herrenschmidt
Cc: Paul Mackerras
Cc: Michael Ellerman
Cc: Chris Metcalf
Cc: Jiri Kosina
Cc: David Sterba
Cc: James Hogan
Cc: Rob Herring
Cc: Eric Anholt
Cc: Stefan Wahren
Cc: Florian Fainelli
Cc: Ray Jui
Cc: Scott Branden
Cc: bcm-kernel-feedback-list@broadcom.com
Cc: "James E.J. Bottomley"
Cc: Helge Deller
Cc: Joachim Eastwood
Cc: Matthias Brugger
Cc: Masahiro Yamada
Cc: Tobias Klauser
Cc: Russell King
Cc: Vineet Gupta
Cc: Richard Genoud
Cc: Alexander Shiyan
Cc: Baruch Siach
Cc: "Maciej W. Rozycki"
Cc: "Uwe Kleine-König"
Cc: Pat Gefre
Cc: "Guilherme G. Piccoli"
Cc: Jason Wessel
Cc: Vladimir Zapolskiy
Cc: Sylvain Lemieux
Cc: Carlo Caione
Cc: Kevin Hilman
Cc: Liviu Dudau
Cc: Sudeep Holla
Cc: Lorenzo Pieralisi
Cc: Andy Gross
Cc: David Brown
Cc: "Andreas Färber"
Cc: Kevin Cernekee
Cc: Laxman Dewangan
Cc: Thierry Reding
Cc: Jonathan Hunter
Cc: Barry Song
Cc: Patrice Chotard
Cc: Maxime Coquelin
Cc: Alexandre Torgue
Cc: "David S. Miller"
Cc: Peter Korsgaard
Cc: Timur Tabi
Cc: Tony Prisk
Cc: Michal Simek
Cc: "Sören Brinkmann"
Cc: Thomas Gleixner
Cc: Kate Stewart
Cc: Philippe Ombredanne
Cc: Jiri Slaby
Signed-off-by: Greg Kroah-Hartman
30 Jul, 2017
1 commit
-
Now that we have a custom printf format specifier, convert users of
full_name to use %pOF instead. This is preparation to remove storing
of the full path string for each node.Signed-off-by: Rob Herring
Acked-by: David S. Miller
Cc: Jiri Slaby
Cc: Benjamin Herrenschmidt
Cc: Paul Mackerras
Cc: Michael Ellerman
Cc: "David S. Miller"
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-serial@vger.kernel.org
Cc: sparclinux@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman
18 May, 2017
1 commit
-
Straighten out the initcall error handling to avoid deregistering a
never-registered tty driver (something which would lead to a
NULL-pointer dereference) in the most unlikely event that driver
registration fails (e.g. we've run out of major numbers).Signed-off-by: Johan Hovold
Signed-off-by: Greg Kroah-Hartman
07 Feb, 2016
1 commit
-
The Kconfig currently controlling compilation of this code is:
drivers/tty/Kconfig:config PPC_EPAPR_HV_BYTECHAN
drivers/tty/Kconfig: bool "ePAPR hypervisor byte channel driver"...meaning that it currently is not being built as a module by anyone.
Lets remove the modular code that is essentially orphaned, so that
when reading the driver there is no doubt it is builtin-only.We explicitly disallow a driver unbind, since that doesn't have a
sensible use case anyway, and it allows us to drop the ".remove"
code for non-modular drivers.Since module_init translates to device_initcall in the non-modular
case, the init ordering remains unchanged with this commit.We also delete the MODULE_LICENSE tag etc. since all that information
is already contained at the top of the file in the comments.Cc: Greg Kroah-Hartman
Cc: Jiri Slaby
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Paul Gortmaker
Signed-off-by: Greg Kroah-Hartman
04 Feb, 2015
1 commit
-
sprop is unused in find_console_handle() since commit a752ee56ad84
("tty: Update hypervisor tty drivers to use core stdout parsing code.")Signed-off-by: Fabian Frederick
Signed-off-by: Greg Kroah-Hartman
15 Dec, 2014
1 commit
-
Pull driver core update from Greg KH:
"Here's the set of driver core patches for 3.19-rc1.They are dominated by the removal of the .owner field in platform
drivers. They touch a lot of files, but they are "simple" changes,
just removing a line in a structure.Other than that, a few minor driver core and debugfs changes. There
are some ath9k patches coming in through this tree that have been
acked by the wireless maintainers as they relied on the debugfs
changes.Everything has been in linux-next for a while"
* tag 'driver-core-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (324 commits)
Revert "ath: ath9k: use debugfs_create_devm_seqfile() helper for seq_file entries"
fs: debugfs: add forward declaration for struct device type
firmware class: Deletion of an unnecessary check before the function call "vunmap"
firmware loader: fix hung task warning dump
devcoredump: provide a one-way disable function
device: Add dev__once variants
ath: ath9k: use debugfs_create_devm_seqfile() helper for seq_file entries
ath: use seq_file api for ath9k debugfs files
debugfs: add helper function to create device related seq_file
drivers/base: cacheinfo: remove noisy error boot message
Revert "core: platform: add warning if driver has no owner"
drivers: base: support cpu cache information interface to userspace via sysfs
drivers: base: add cpu_device_create to support per-cpu devices
topology: replace custom attribute macros with standard DEVICE_ATTR*
cpumask: factor out show_cpumap into separate helper function
driver core: Fix unbalanced device reference in drivers_probe
driver core: fix race with userland in device_add()
sysfs/kernfs: make read requests on pre-alloc files use the buffer.
sysfs/kernfs: allow attributes to request write buffer be pre-allocated.
fs: sysfs: return EGBIG on write if offset is larger than file size
...
26 Nov, 2014
1 commit
-
Convert the pr_warning to the more common pr_warn.
Other miscellanea:
o Convert unusual PR_FMT define and uses to pr_fmt
o Remove unnecessary OOM message
o Fix grammar in an error message
o Convert a pr_warning with a KERN_ERR to pr_errSigned-off-by: Joe Perches
Signed-off-by: Greg Kroah-Hartman
20 Oct, 2014
1 commit
-
A platform_driver does not need to set an owner, it will be populated by the
driver core.Signed-off-by: Wolfram Sang
27 Jun, 2014
1 commit
-
The evh_bytechan, hvc_opal and hvc_vio drivers all open code the parsing
of the stdout node in the device tree. This patch simplifies the driver
by removing the duplicated functionality.Signed-off-by: Grant Likely
10 Oct, 2013
1 commit
-
Powerpc is a mess of implicit includes by prom.h. Add the necessary
explicit includes to drivers in preparation of prom.h cleanup.Signed-off-by: Rob Herring
Acked-by: Grant Likely
21 May, 2013
1 commit
-
We have registered platform driver when module init, and
need unregister it when module exit.Signed-off-by: Wei Yongjun
Signed-off-by: Greg Kroah-Hartman
19 Mar, 2013
1 commit
-
It allows for cleaning up on a considerable amount of places. They did
port_get, wakeup, kref_put. Now the only thing needed is to call
tty_port_tty_wakeup which does exactly that.One exception is ifx6x60 where tty_wakeup was open-coded. We now call
tty_wakeup properly there.Signed-off-by: Jiri Slaby
Signed-off-by: Greg Kroah-Hartman
16 Jan, 2013
3 commits
-
Now, we start converting tty buffer functions to actually use
tty_port. This will allow us to get rid of the need of tty in many
call sites. Only tty_port will needed and hence no more
tty_port_tty_get in those paths.Now, the one where most of tty_port_tty_get gets removed:
tty_flip_buffer_push.IOW we also closed all the races in drivers not using tty_port_tty_get
at all yet.Also we move tty_flip_buffer_push declaration from include/linux/tty.h
to include/linux/tty_flip.h to all others while we are changing it
anyway.Signed-off-by: Jiri Slaby
Signed-off-by: Greg Kroah-Hartman -
Now, we start converting tty buffer functions to actually use
tty_port. This will allow us to get rid of the need of tty in many
call sites. Only tty_port will needed and hence no more
tty_port_tty_get in those paths.tty_insert_flip_string this time.
Signed-off-by: Jiri Slaby
Signed-off-by: Greg Kroah-Hartman -
Now, we start converting tty buffer functions to actually use
tty_port. This will allow us to get rid of the need of tty pointer in
many call sites. Only tty_port will be needed and hence no more
tty_port_tty_get calls in those paths.Here we start with tty_buffer_request_room.
Signed-off-by: Jiri Slaby
Signed-off-by: Greg Kroah-Hartman
22 Nov, 2012
1 commit
-
CONFIG_HOTPLUG is going away as an option so __devinit is no longer
needed.Signed-off-by: Bill Pemberton
Cc: Jiri Slaby
Cc: Alan Cox
Cc: Lucas Tavares
Cc: "David S. Miller"
Cc: Peter Korsgaard
Cc: Tony Prisk
Acked-by: Tobias Klauser
Acked-by: Nicolas Ferre
Signed-off-by: Greg Kroah-Hartman
16 Nov, 2012
1 commit
-
After commit "TTY: move tty buffers to tty_port", the tty buffers are
not freed in some drivers. This is because tty_port_destructor is not
called whenever a tty_port is freed. This was an assumption I counted
with but was unfortunately untrue. So fix the drivers to fulfil this
assumption.To be sure, the TTY buffers (and later some stuff) are gone along with
the tty_port, we have to call tty_port_destroy at tear-down places.
This is mostly where the structure containing a tty_port is freed.
This patch does exactly that -- put tty_port_destroy at those places.Signed-off-by: Jiri Slaby
Signed-off-by: Greg Kroah-Hartman
14 Aug, 2012
1 commit
-
Currently we have no way to assign tty->port while performing tty
installation. There are two ways to provide the link tty_struct =>
tty_port. Either by calling tty_port_install from tty->ops->install or
tty_port_register_device called instead of tty_register_device when
the device is being set up after connected.In this patch we modify most of the drivers to do the latter. When the
drivers use tty_register_device and we have tty_port already, we
switch to tty_port_register_device. So we have the tty_struct =>
tty_port link for free for those.Signed-off-by: Jiri Slaby
Acked-by: Alan Cox
Signed-off-by: Greg Kroah-Hartman
09 Mar, 2012
1 commit
-
All num, magic and owner are set by alloc_tty_driver. No need to
re-set them on each allocation site.pti driver sets something different to what it passes to
alloc_tty_driver. It is not a bug, since we don't use the lines
parameter in any way. Anyway this is fixed, and now we do the right
thing.Signed-off-by: Jiri Slaby
Acked-by: Tilman Schmidt
Signed-off-by: Greg Kroah-Hartman
27 Sep, 2011
1 commit
-
The ePAPR hypervisor byte channel console driver only supports one byte
channel as a console, and the byte channel handle is stored in a global
variable. It doesn't make any sense to pass that handle as a parameter
to the console functions, since these functions already have access to the
global variable.Signed-off-by: Timur Tabi
Signed-off-by: Greg Kroah-Hartman
27 Aug, 2011
1 commit
-
The ePAPR hypervisor byte channel driver is supposed to work on all
ePAPR-compliant embedded PowerPC systems, but it had a reference to the MSR_GS
bit, which is available only on Book-E systems.Also fix a couple integer-to-pointer typecast problems.
Reported-by: Stephen Rothwell
Signed-off-by: Timur Tabi
Signed-off-by: Greg Kroah-Hartman
24 Aug, 2011
1 commit
-
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
Signed-off-by: Greg Kroah-Hartman