[PATCH V2] powerpc: Export PIR data through sysfs

[Ananth N Mavinakayanahalli <ananth@in.ibm.com>]

On Fri, Nov 11, 2011 at 10:17:55AM +0530, Ananth N Mavinakayanahalli wrote:
> > 
> > At this rate we're going to end up with no bits left for CPU features
> > way too quickly... Especially for something we only care about once at
> > boot time.
> >
> > Wouldn't CPU_FTR_PPCAS_ARCH_V2 be a good enough test ?
> 
> /me checks Cell manuals... yes, that test would be good enough. I will
> cook up a patch to use this.

Here it is...
---

From: Ananth N Mavinakayanahalli <ananth@in.ibm.com>

The Processor Identification Register (PIR) on some powerpc platforms
provides information to decode the processor identification tag that
can be used for node/core/thread affinity tests and for debugging.
Decoding this information is platform specific.

Export PIR contents through sysfs.

[V2] Use CPU_FTR_PPCAS_ARCH_V2 as a test for PIR's presence per
BenH's suggestion.

Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
---
 arch/powerpc/kernel/sysfs.c |    8 ++++++++
 1 file changed, 8 insertions(+)

Index: linux-3.2-rc1/arch/powerpc/kernel/sysfs.c
===================================================================
--- linux-3.2-rc1.orig/arch/powerpc/kernel/sysfs.c
+++ linux-3.2-rc1/arch/powerpc/kernel/sysfs.c
@@ -177,11 +177,13 @@ SYSFS_PMCSETUP(mmcra, SPRN_MMCRA);
 SYSFS_PMCSETUP(purr, SPRN_PURR);
 SYSFS_PMCSETUP(spurr, SPRN_SPURR);
 SYSFS_PMCSETUP(dscr, SPRN_DSCR);
+SYSFS_PMCSETUP(pir, SPRN_PIR);
 
 static SYSDEV_ATTR(mmcra, 0600, show_mmcra, store_mmcra);
 static SYSDEV_ATTR(spurr, 0600, show_spurr, NULL);
 static SYSDEV_ATTR(dscr, 0600, show_dscr, store_dscr);
 static SYSDEV_ATTR(purr, 0600, show_purr, store_purr);
+static SYSDEV_ATTR(pir, 0400, show_pir, NULL);
 
 unsigned long dscr_default = 0;
 EXPORT_SYMBOL(dscr_default);
@@ -392,6 +394,9 @@ static void __cpuinit register_cpu_onlin
 
 	if (cpu_has_feature(CPU_FTR_DSCR))
 		sysdev_create_file(s, &attr_dscr);
+
+	if (cpu_has_feature(CPU_FTR_PPCAS_ARCH_V2))
+		sysdev_create_file(s, &attr_pir);
 #endif /* CONFIG_PPC64 */
 
 	cacheinfo_cpu_online(cpu);
@@ -462,6 +467,9 @@ static void unregister_cpu_online(unsign
 
 	if (cpu_has_feature(CPU_FTR_DSCR))
 		sysdev_remove_file(s, &attr_dscr);
+
+	if (cpu_has_feature(CPU_FTR_PPCAS_ARCH_V2))
+		sysdev_remove_file(s, &attr_pir);
 #endif /* CONFIG_PPC64 */
 
 	cacheinfo_cpu_offline(cpu);