IPMI: Driver for Sparc T4/T5/T7 Platforms

IPMI: Driver for Sparc T4/T5/T7 Platforms

Functional IPMI interface driver for Sparc T4/T5/T7. This will
probably also work for other platforms that use an iLOM channel
for IPMI services, including older and future ones, though these
have not been tested.

This driver provides the transport between the IPMI message layer
and the Sparc platform IPMI endpoint in iLOM. The Virtual Logical
Domain Channel (VLDC) driver claims the host endpoint, and we call
it to move data to/from iLOM. So there is an unusual dependency
on another loadable module which requires several compromises
until we work out a plan to restructure the VLDC driver to provide
a cleaner interface:

 * An artificial symbolic dependency on vldc is created so that
   "modprobe ipmi_si" will ensure that vldc is loaded also.

 * ipmi_vldc uses filp_open/kernel_read/kernel_write on device
   files provided by vldc, ie, /sys/class/vldc/ipmi/mode and
   /dev/vldc/ipmi.

Bug 22804422 has been created to deal with these issues.

Sending this driver upstream is on hold until we work out these
issues. Also, the vldc driver itself has not yet been sent upstream
and that is obviously a prerequisite.

Orabug: 22658348

Signed-off-by: Rob Gardner <rob.gardner@oracle.com>
(cherry picked from commit 6083e586b068ae159c8335adc2d210e7b7f66d27)
(cherry picked from commit 9944e6442b962c2945f2a59ef7c6ff81d0e95172)
Signed-off-by: Allen Pais <allen.pais@oracle.com>
(cherry picked from commit e76d315b514e424a8623c51eaa526a6d2ac52a89)
(cherry picked from commit dfcab0a3eef7ebd4cc2fda9865f42ff114b46459)