[PATCH v6 2/3] riscv: cacheinfo: initialize cacheinfo's level and type from ACPI PPTT

[Yunhui Cui]

Before cacheinfo can be built correctly, we need to initialize level
and type. Since RISC-V currently does not have a register group that
describes cache-related attributes like ARM64, we cannot obtain them
directly, so now we obtain cache leaves from the ACPI PPTT table
(acpi_get_cache_info()) and set the cache type through split_levels.

Suggested-by: Jeremy Linton <jeremy.linton at arm.com>
Suggested-by: Sudeep Holla <sudeep.holla at arm.com>
Reviewed-by: Conor Dooley <conor.dooley at microchip.com>
Reviewed-by: Sunil V L <sunilvl at ventanamicro.com>
Reviewed-by: Jeremy Linton <jeremy.linton at arm.com>
Reviewed-by: Sudeep Holla <sudeep.holla at arm.com>
Signed-off-by: Yunhui Cui <cuiyunhui at bytedance.com>
---
 arch/riscv/kernel/cacheinfo.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/arch/riscv/kernel/cacheinfo.c b/arch/riscv/kernel/cacheinfo.c
index 30a6878287ad..d6c108c50cba 100644
--- a/arch/riscv/kernel/cacheinfo.c
+++ b/arch/riscv/kernel/cacheinfo.c
@@ -3,6 +3,7 @@
  * Copyright (C) 2017 SiFive
  */
 
+#include <linux/acpi.h>
 #include <linux/cpu.h>
 #include <linux/of.h>
 #include <asm/cacheinfo.h>
@@ -78,6 +79,27 @@ int populate_cache_leaves(unsigned int cpu)
 	struct device_node *prev = NULL;
 	int levels = 1, level = 1;
 
+	if (!acpi_disabled) {
+		int ret, fw_levels, split_levels;
+
+		ret = acpi_get_cache_info(cpu, &fw_levels, &split_levels);
+		if (ret)
+			return ret;
+
+		BUG_ON((split_levels > fw_levels) ||
+		       (split_levels + fw_levels > this_cpu_ci->num_leaves));
+
+		for (; level <= this_cpu_ci->num_levels; level++) {
+			if (level <= split_levels) {
+				ci_leaf_init(this_leaf++, CACHE_TYPE_DATA, level);
+				ci_leaf_init(this_leaf++, CACHE_TYPE_INST, level);
+			} else {
+				ci_leaf_init(this_leaf++, CACHE_TYPE_UNIFIED, level);
+			}
+		}
+		return 0;
+	}
+
 	if (of_property_read_bool(np, "cache-size"))
 		ci_leaf_init(this_leaf++, CACHE_TYPE_UNIFIED, level);
 	if (of_property_read_bool(np, "i-cache-size"))
-- 
2.20.1