[POWERPC] Add DSCR SPR to sysfs

POWER6 adds a new SPR, the data stream control register (DSCR). It can
be used to adjust how agressive the prefetch mechanisms are.

Its possible we may want to context switch this, but for now just export
it to userspace via sysfs so we can adjust it.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c
index 63ed265b7f09..22daba56c865 100644
--- a/arch/powerpc/kernel/sysfs.c
+++ b/arch/powerpc/kernel/sysfs.c
@@ -181,6 +181,7 @@ SYSFS_PMCSETUP(pmc6, SPRN_PMC6);
 SYSFS_PMCSETUP(pmc7, SPRN_PMC7);
 SYSFS_PMCSETUP(pmc8, SPRN_PMC8);
 SYSFS_PMCSETUP(purr, SPRN_PURR);
+SYSFS_PMCSETUP(dscr, SPRN_DSCR);
 
 static SYSDEV_ATTR(mmcr0, 0600, show_mmcr0, store_mmcr0);
 static SYSDEV_ATTR(mmcr1, 0600, show_mmcr1, store_mmcr1);
@@ -194,6 +195,7 @@ static SYSDEV_ATTR(pmc6, 0600, show_pmc6, store_pmc6);
 static SYSDEV_ATTR(pmc7, 0600, show_pmc7, store_pmc7);
 static SYSDEV_ATTR(pmc8, 0600, show_pmc8, store_pmc8);
 static SYSDEV_ATTR(purr, 0600, show_purr, NULL);
+static SYSDEV_ATTR(dscr, 0600, show_dscr, store_dscr);
 
 static void register_cpu_online(unsigned int cpu)
 {
@@ -231,6 +233,9 @@ static void register_cpu_online(unsigned int cpu)
 
         if (cpu_has_feature(CPU_FTR_PURR))
                 sysdev_create_file(s, &attr_purr);
+
+        if (cpu_has_feature(CPU_FTR_DSCR))
+                sysdev_create_file(s, &attr_dscr);
 }
 
 #ifdef CONFIG_HOTPLUG_CPU
@@ -272,6 +277,9 @@ static void unregister_cpu_online(unsigned int cpu)
 
         if (cpu_has_feature(CPU_FTR_PURR))
                 sysdev_remove_file(s, &attr_purr);
+
+        if (cpu_has_feature(CPU_FTR_DSCR))
+                sysdev_remove_file(s, &attr_dscr);
 }
 #endif /* CONFIG_HOTPLUG_CPU */