MIPS: Allow L2 prefetch to be configured via debugfs

When debugging or examining the performance of a system it can be useful
to examine the effect of L2 prefetching. Provide an optional debugfs
entry to allow a user to enable or disable L2 prefetching.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/11182/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/Kconfig.debug b/arch/mips/Kconfig.debug
index 13d7965..b43e288 100644
--- a/arch/mips/Kconfig.debug
+++ b/arch/mips/Kconfig.debug
@@ -149,4 +149,14 @@
 
 endif # CPU_MIPSR6
 
+config SCACHE_DEBUGFS
+	bool "L2 cache debugfs entries"
+	depends on DEBUG_FS
+	help
+	  Enable this to allow parts of the L2 cache configuration, such as
+	  whether or not prefetching is enabled, to be exposed to userland
+	  via debugfs.
+
+	  If unsure, say N.
+
 endmenu