[PATCH 3.16.y-ckt 179/185] x86/iosf: Add Kconfig prompt for IOSF_MBI selection

[Luis Henriques]

3.16.7-ckt15 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: "David E. Box" <david.e.box at linux.intel.com>

commit aa8e4f22ab7773352ba3895597189b8097f2c307 upstream.

Fixes an error in having the iosf build as 'default m'. On X86 SoC's the iosf
sideband is the only way to access information for some registers, as opposed to
through MSR's on other Intel architectures. While selecting IOSF_MBI is
preferred, it does mean carrying extra code on non-SoC architectures. This
exports the selection to the user, allowing those driver writers to compile out
iosf code if it's not being built.

Signed-off-by: David E. Box <david.e.box at linux.intel.com>
Link: http://lkml.kernel.org/r/1409175640-32426-2-git-send-email-david.e.box@linux.intel.com
Signed-off-by: H. Peter Anvin <hpa at linux.intel.com>
Cc: William Dauchy <william at gandi.net>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 arch/x86/Kconfig | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 04fe4a66c3ec..a51d8286c75d 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2405,9 +2405,19 @@ config X86_DMA_REMAP
 	depends on STA2X11
 
 config IOSF_MBI
-	tristate
-	default m
+	tristate "Intel System On Chip IOSF Sideband support"
 	depends on PCI
+	---help---
+	  Enables sideband access to mailbox registers on SoC's. The sideband is
+	  available on the following platforms. This list is not meant to be
+	  exclusive.
+	   - BayTrail
+	   - Cherryview
+	   - Braswell
+	   - Quark
+
+	  You should say Y if you are running a kernel on one of these
+	  platforms.
 
 source "net/Kconfig"