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  1. 29 6月, 2011 4 次提交
    • B
      powerpc/pseries: Move hvsi support into a library · 17bdc6c0
      由 Benjamin Herrenschmidt 提交于 
      This will allow a different backend to share it
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
      17bdc6c0
    • B
      powerpc/pseries: Re-implement HVSI as part of hvc_vio · 4d2bb3f5
      由 Benjamin Herrenschmidt 提交于 
      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: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
      4d2bb3f5
    • B
      powerpc/pseries: Factor HVSI header struct in packet definitions · 048bee77
      由 Benjamin Herrenschmidt 提交于 
      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: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
      048bee77
    • B
      powerpc/hvsi: Move HVSI protocol definitions to a header file · 725e789f
      由 Benjamin Herrenschmidt 提交于 
      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: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
      725e789f
  3. 09 6月, 2011 2 次提交
  5. 08 6月, 2011 13 次提交
  7. 07 6月, 2011 21 次提交