powerpc/time: Move timebase functions into new asm/vdso/timebase.h

In order to easily use get_tb() from C VDSO, move timebase
functions into a new header named asm/vdso/timebase.h

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201126131006.2431205-3-mpe@ellerman.id.au

1 files changed, 71 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/vdso/timebase.h b/arch/powerpc/include/asm/vdso/timebase.h
new file mode 100644
index 000000000000..ac6769b348c6
--- /dev/null
+++ b/arch/powerpc/include/asm/vdso/timebase.h
@@ -0,0 +1,71 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Common timebase prototypes and such for all ppc machines.
+ */
+
+#ifndef _ASM_POWERPC_VDSO_TIMEBASE_H
+#define _ASM_POWERPC_VDSO_TIMEBASE_H
+
+#include <asm/reg.h>
+
+#if defined(CONFIG_PPC_CELL) || defined(CONFIG_E500)
+#define mftb()		({unsigned long rval;				\
+			asm volatile(					\
+				"90:	mfspr %0, %2;\n"		\
+				ASM_FTR_IFSET(				\
+					"97:	cmpwi %0,0;\n"		\
+					"	beq- 90b;\n", "", %1)	\
+			: "=r" (rval) \
+			: "i" (CPU_FTR_CELL_TB_BUG), "i" (SPRN_TBRL) : "cr0"); \
+			rval;})
+#elif defined(CONFIG_PPC_8xx)
+#define mftb()		({unsigned long rval;	\
+			asm volatile("mftbl %0" : "=r" (rval)); rval;})
+#else
+#define mftb()		({unsigned long rval;	\
+			asm volatile("mfspr %0, %1" : \
+				     "=r" (rval) : "i" (SPRN_TBRL)); rval;})
+#endif /* !CONFIG_PPC_CELL */
+
+#if defined(CONFIG_PPC_8xx)
+#define mftbu()		({unsigned long rval;	\
+			asm volatile("mftbu %0" : "=r" (rval)); rval;})
+#else
+#define mftbu()		({unsigned long rval;	\
+			asm volatile("mfspr %0, %1" : "=r" (rval) : \
+				"i" (SPRN_TBRU)); rval;})
+#endif
+
+#define mttbl(v)	asm volatile("mttbl %0":: "r"(v))
+#define mttbu(v)	asm volatile("mttbu %0":: "r"(v))
+
+/* For compatibility, get_tbl() is defined as get_tb() on ppc64 */
+static inline unsigned long get_tbl(void)
+{
+	return mftb();
+}
+
+static inline u64 get_tb(void)
+{
+	unsigned int tbhi, tblo, tbhi2;
+
+	if (IS_ENABLED(CONFIG_PPC64))
+		return mftb();
+
+	do {
+		tbhi = mftbu();
+		tblo = mftb();
+		tbhi2 = mftbu();
+	} while (tbhi != tbhi2);
+
+	return ((u64)tbhi << 32) | tblo;
+}
+
+static inline void set_tb(unsigned int upper, unsigned int lower)
+{
+	mtspr(SPRN_TBWL, 0);
+	mtspr(SPRN_TBWU, upper);
+	mtspr(SPRN_TBWL, lower);
+}
+
+#endif /* _ASM_POWERPC_VDSO_TIMEBASE_H */