linux/drivers/tty/hvc, branch v3.1

powerpc/pseries: Fix hvc_vio.c build due to recent changes

2011-07-20T08:01:48Z

For some reason I didn't notice the failure in my test builds, probably lacking caffeine or something... Signed-off-by: Benjamin Herrenschmidt

hvc_console: Add kdb support

2011-07-19T05:13:07Z

Add poll_get_char and poll_put_char for kdb. Enable kdb at boot with: kgdboc=hvc0 or at runtime with: echo hvc0 > /sys/module/kgdboc/parameters/kgdboc Signed-off-by: Anton Blanchard Signed-off-by: Benjamin Herrenschmidt

powerpc/pseries: Fix hvterm_raw_get_chars to accept < 16 chars, fixing xmon

2011-07-19T05:13:07Z

commit 4d2bb3f50036 (powerpc/pseries: Re-implement HVSI as part of hvc_vio) changed udbg_getc to be based on hvterm_raw_get_chars. Unfortunately hvterm_raw_get_chars returns -EAGAIN if you ask for anything less than 16 characters. As a result xmon no longer accepts input and prints a stream of junk to the screen. The recent change highlights a problem that xmon on pseries VIO has had all along, that it can drop input characters. The issue is the hypervisor call does not take a count argument and can return up to 16 characters. This patch adds a per vterm buffer that we copy input data into and give it out as requested. Signed-off-by: Anton Blanchard Signed-off-by: Benjamin Herrenschmidt

hvc_console: Improve tty/console put_chars handling

2011-07-19T05:13:05Z

Currently, the hvc_console_print() function drops console output if the hvc backend's put_chars() returns 0. This patch changes this behavior to allow a retry through returning -EAGAIN. This change also affects the hvc_push() function. Both functions are changed to handle -EAGAIN and to retry the put_chars() operation. If a hvc backend returns -EAGAIN, the retry handling differs: - hvc_console_print() spins to write the complete console output. - hvc_push() behaves the same way as for returning 0. Now hvc backends can indirectly control the way how console output is handled through the hvc console layer. Signed-off-by: Hendrik Brueckner Acked-by: Anton Blanchard Cc: Signed-off-by: Benjamin Herrenschmidt

powerpc/hvsi: Fix conflict with old HVSI driver

2011-07-01T03:10:21Z

A mix of think & mismerge on my side caused a problem where both the new hvsi_lib and the old hvsi driver gets compiled and try to define symbols with the same name. This fixes it by renaming the hvsi_lib exported symbols. Signed-off-by: Benjamin Herrenschmidt

powerpc/pseries: Move hvsi support into a library

2011-06-29T07:48:37Z

This will allow a different backend to share it Signed-off-by: Benjamin Herrenschmidt

powerpc/pseries: Re-implement HVSI as part of hvc_vio

2011-06-29T07:48:35Z

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

powerpc/pseries: Factor HVSI header struct in packet definitions

2011-06-29T07:48:30Z

Embed the struct hvsi_header in the various packet definitions rather than open coding it multiple times. Will help provide stronger type checking. Signed-off-by: Benjamin Herrenschmidt

powerpc/hvsi: Move HVSI protocol definitions to a header file

2011-06-29T07:48:28Z

This moves various HVSI protocol definitions from the hvsi.c driver to a header file that can be used later on by a udbg implementation Signed-off-by: Benjamin Herrenschmidt

Fix common misspellings

2011-03-31T14:26:23Z

Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi