IBM Real-Time "SMI Free" mode driver -v7

After a period of RFC for this driver, I think it is ready
for inclusion in the platform-driver-x86 tree, hopefully to
be staged in the next merge window into Linus's tree.

--Vernon

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IBM Real-Time "SMI Free" mode driver

This driver supports the Real-Time Linux (RTL) BIOS feature.
The RTL feature allows non-fatal System Management Interrupts
(SMIs) to be disabled on supported IBM platforms and is
intended to be coupled with a user-space daemon to monitor
the hardware in a way that can be prioritized and scheduled
to better suit the requirements for the system.

The Device is presented as a special "_RTL_" table to the OS
in the Extended BIOS Data Area.  There is a simple protocol
for entering and exiting the mode at runtime.  This driver
creates a simple sysfs interface to allow a simple entry and
exit from RTL mode in the UFI/BIOS.

Since the driver is specific to IBM SystemX hardware (x86-
based servers) it only builds on x86 builds.  To reduce the
risk of loading on the wrong hardware, the module uses DMI
information and checks a list of servers that are known to
work.

Signed-off-by: Vernon Mauery <vernux@us.ibm.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 91e431b6f20f..faec777b1ed4 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -615,6 +615,22 @@ config INTEL_IPS
           functionality.  If in doubt, say Y here; it will only load on
           supported platforms.
 
+config IBM_RTL
+        tristate "Device driver to enable PRTL support"
+        depends on X86 && PCI
+        ---help---
+         Enable support for IBM Premium Real Time Mode (PRTM).
+         This module will allow you the enter and exit PRTM in the BIOS via
+         sysfs on platforms that support this feature.  System in PRTM will
+         not receive CPU-generated SMIs for recoverable errors.  Use of this
+         feature without proper support may void your hardware warranty.
+
+         If the proper BIOS support is found the driver will load and create
+         /sys/devices/system/ibm_rtl/.  The "state" variable will indicate
+         whether or not the BIOS is in PRTM.
+         state = 0 (BIOS SMIs on)
+         state = 1 (BIOS SMIs off)
+
 config XO1_RFKILL
         tristate "OLPC XO-1 software RF kill switch"
         depends on OLPC