[PATCH V2] riscv: export cpu/freq invariant to scheduler

[Song Shuai <suagrfillet@gmail.com>]

RISC-V now manages CPU topology using arch_topology which provides
CPU capacity and frequency related interfaces to access the cpu/freq
invariant in possible heterogeneous or DVFS-enabled platforms.

Here adds topology.h file to export the arch_topology interfaces for
replacing the scheduler's constant-based cpu/freq invariant accounting.

Signed-off-by: Song Shuai <suagrfillet@gmail.com>
---
changes from V1:
  - fix the leading underscore and tidy the patch up 
---
 arch/riscv/include/asm/topology.h | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)
 create mode 100644 arch/riscv/include/asm/topology.h

diff --git a/arch/riscv/include/asm/topology.h b/arch/riscv/include/asm/topology.h
new file mode 100644
index 000000000000..727e8d163a3b
--- /dev/null
+++ b/arch/riscv/include/asm/topology.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_RISCV_TOPOLOGY_H
+#define _ASM_RISCV_TOPOLOGY_H
+
+#include <linux/arch_topology.h>
+
+/* Replace task scheduler's default frequency-invariant accounting */
+#define arch_scale_freq_tick	topology_scale_freq_tick
+#define arch_set_freq_scale	topology_set_freq_scale
+#define arch_scale_freq_capacity	topology_get_freq_scale
+#define arch_scale_freq_invariant	topology_scale_freq_invariant
+
+/* Replace task scheduler's default cpu-invariant accounting */
+#define arch_scale_cpu_capacity	topology_get_cpu_scale
+
+/* Enable topology flag updates */
+#define arch_update_cpu_topology	topology_update_cpu_topology
+
+#include <asm-generic/topology.h>
+#endif /* _ASM_RISCV_TOPOLOGY_H */
-- 
2.20.1