powerpc/4xx: Extended DCR support v2
This adds supports to the "extended" DCR addressing via the indirect
mfdcrx/mtdcrx instructions supported by some 4xx cores (440H6 and
later).
I enabled the feature for now only on AMCC 460 chips.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
Acked-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/include/asm/dcr-native.h b/arch/powerpc/include/asm/dcr-native.h
index 72d2b72..7d2e623 100644
--- a/arch/powerpc/include/asm/dcr-native.h
+++ b/arch/powerpc/include/asm/dcr-native.h
@@ -23,6 +23,7 @@
#ifndef __ASSEMBLY__
#include <linux/spinlock.h>
+#include <asm/cputable.h>
typedef struct {
unsigned int base;
@@ -39,23 +40,45 @@
#define dcr_read_native(host, dcr_n) mfdcr(dcr_n + host.base)
#define dcr_write_native(host, dcr_n, value) mtdcr(dcr_n + host.base, value)
-/* Device Control Registers */
-void __mtdcr(int reg, unsigned int val);
-unsigned int __mfdcr(int reg);
+/* Table based DCR accessors */
+extern void __mtdcr(unsigned int reg, unsigned int val);
+extern unsigned int __mfdcr(unsigned int reg);
+
+/* mfdcrx/mtdcrx instruction based accessors. We hand code
+ * the opcodes in order not to depend on newer binutils
+ */
+static inline unsigned int mfdcrx(unsigned int reg)
+{
+ unsigned int ret;
+ asm volatile(".long 0x7c000206 | (%0 << 21) | (%1 << 16)"
+ : "=r" (ret) : "r" (reg));
+ return ret;
+}
+
+static inline void mtdcrx(unsigned int reg, unsigned int val)
+{
+ asm volatile(".long 0x7c000306 | (%0 << 21) | (%1 << 16)"
+ : : "r" (val), "r" (reg));
+}
+
#define mfdcr(rn) \
({unsigned int rval; \
- if (__builtin_constant_p(rn)) \
+ if (__builtin_constant_p(rn) && rn < 1024) \
asm volatile("mfdcr %0," __stringify(rn) \
: "=r" (rval)); \
+ else if (likely(cpu_has_feature(CPU_FTR_INDEXED_DCR))) \
+ rval = mfdcrx(rn); \
else \
rval = __mfdcr(rn); \
rval;})
#define mtdcr(rn, v) \
do { \
- if (__builtin_constant_p(rn)) \
+ if (__builtin_constant_p(rn) && rn < 1024) \
asm volatile("mtdcr " __stringify(rn) ",%0" \
: : "r" (v)); \
+ else if (likely(cpu_has_feature(CPU_FTR_INDEXED_DCR))) \
+ mtdcrx(rn, v); \
else \
__mtdcr(rn, v); \
} while (0)
@@ -69,8 +92,13 @@
unsigned int val;
spin_lock_irqsave(&dcr_ind_lock, flags);
- __mtdcr(base_addr, reg);
- val = __mfdcr(base_data);
+ if (cpu_has_feature(CPU_FTR_INDEXED_DCR)) {
+ mtdcrx(base_addr, reg);
+ val = mfdcrx(base_data);
+ } else {
+ __mtdcr(base_addr, reg);
+ val = __mfdcr(base_data);
+ }
spin_unlock_irqrestore(&dcr_ind_lock, flags);
return val;
}
@@ -81,8 +109,13 @@
unsigned long flags;
spin_lock_irqsave(&dcr_ind_lock, flags);
- __mtdcr(base_addr, reg);
- __mtdcr(base_data, val);
+ if (cpu_has_feature(CPU_FTR_INDEXED_DCR)) {
+ mtdcrx(base_addr, reg);
+ mtdcrx(base_data, val);
+ } else {
+ __mtdcr(base_addr, reg);
+ __mtdcr(base_data, val);
+ }
spin_unlock_irqrestore(&dcr_ind_lock, flags);
}
@@ -93,9 +126,15 @@
unsigned int val;
spin_lock_irqsave(&dcr_ind_lock, flags);
- __mtdcr(base_addr, reg);
- val = (__mfdcr(base_data) & ~clr) | set;
- __mtdcr(base_data, val);
+ if (cpu_has_feature(CPU_FTR_INDEXED_DCR)) {
+ mtdcrx(base_addr, reg);
+ val = (mfdcrx(base_data) & ~clr) | set;
+ mtdcrx(base_data, val);
+ } else {
+ __mtdcr(base_addr, reg);
+ val = (__mfdcr(base_data) & ~clr) | set;
+ __mtdcr(base_data, val);
+ }
spin_unlock_irqrestore(&dcr_ind_lock, flags);
}