[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>

diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c
index 63ed265b7f0936765a1cc7bc9356404acf679e68..22daba56c865a304075582126426c61f958801ee 100644 (file)
--- 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 */
 

diff --git a/include/asm-powerpc/cputable.h b/include/asm-powerpc/cputable.h
index 6fe5c9d4ca3b946e2ad5f348070851b6e039d086..782adbf1f7aae92d584878f9ed870922de10c6ad 100644 (file)
--- a/include/asm-powerpc/cputable.h
+++ b/include/asm-powerpc/cputable.h
@@ -152,6 +152,7 @@ extern void do_feature_fixups(unsigned long value, void *fixup_start,
 #define CPU_FTR_PURR                   LONG_ASM_CONST(0x0000400000000000)
 #define CPU_FTR_CELL_TB_BUG            LONG_ASM_CONST(0x0000800000000000)
 #define CPU_FTR_SPURR                  LONG_ASM_CONST(0x0001000000000000)
+#define CPU_FTR_DSCR                   LONG_ASM_CONST(0x0002000000000000)
 
 #ifndef __ASSEMBLY__
 
@@ -330,13 +331,14 @@ extern void do_feature_fixups(unsigned long value, void *fixup_start,
            CPU_FTR_HPTE_TABLE | CPU_FTR_PPCAS_ARCH_V2 | CPU_FTR_CTRL | \
            CPU_FTR_MMCRA | CPU_FTR_SMT | \
            CPU_FTR_COHERENT_ICACHE | CPU_FTR_LOCKLESS_TLBIE | \
-           CPU_FTR_PURR | CPU_FTR_SPURR | CPU_FTR_REAL_LE)
+           CPU_FTR_PURR | CPU_FTR_SPURR | CPU_FTR_REAL_LE | \
+           CPU_FTR_DSCR)
 #define CPU_FTRS_POWER6X (CPU_FTR_SPLIT_ID_CACHE | CPU_FTR_USE_TB | \
            CPU_FTR_HPTE_TABLE | CPU_FTR_PPCAS_ARCH_V2 | CPU_FTR_CTRL | \
            CPU_FTR_MMCRA | CPU_FTR_SMT | \
            CPU_FTR_COHERENT_ICACHE | CPU_FTR_LOCKLESS_TLBIE | \
            CPU_FTR_PURR | CPU_FTR_CI_LARGE_PAGE | \
-           CPU_FTR_SPURR | CPU_FTR_REAL_LE)
+           CPU_FTR_SPURR | CPU_FTR_REAL_LE | CPU_FTR_DSCR)
 #define CPU_FTRS_CELL  (CPU_FTR_SPLIT_ID_CACHE | CPU_FTR_USE_TB | \
            CPU_FTR_HPTE_TABLE | CPU_FTR_PPCAS_ARCH_V2 | CPU_FTR_CTRL | \
            CPU_FTR_ALTIVEC_COMP | CPU_FTR_MMCRA | CPU_FTR_SMT | \

diff --git a/include/asm-powerpc/reg.h b/include/asm-powerpc/reg.h
index 6faae7b14d5540f0e5cdcd13b3a31c195d7d980b..cacdecca610c0c023719799a79778e1e97c0b96e 100644 (file)
--- a/include/asm-powerpc/reg.h
+++ b/include/asm-powerpc/reg.h
@@ -143,6 +143,7 @@
 
 /* Special Purpose Registers (SPRNs)*/
 #define SPRN_CTR       0x009   /* Count Register */
+#define SPRN_DSCR      0x11
 #define SPRN_CTRLF     0x088
 #define SPRN_CTRLT     0x098
 #define   CTRL_CT      0xc0000000      /* current thread */