drivers: base cacheinfo: Add support for ACPI based firmware tables

Call ACPI cache parsing routines from base cacheinfo code if ACPI
is enabled. Also stub out cache_setup_acpi and acpi_find_last_cache_level
so that individual architectures can enable ACPI topology parsing.
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Vijaya Kumar K <vkilari@codeaurora.org>
Tested-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Tested-by: Tomasz Nowicki <Tomasz.Nowicki@cavium.com>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

drivers/base/cacheinfo.c

@@ -206,7 +206,7 @@ static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
 					   struct cacheinfo *sib_leaf)
 {
 	/*
-	 * For non-DT systems, assume unique level 1 cache, system-wide
+	 * For non-DT/ACPI systems, assume unique level 1 caches, system-wide
 	 * shared caches for all other levels. This will be used only if
 	 * arch specific code has not populated shared_cpu_map
 	 */
@@ -214,6 +214,11 @@ static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
 }
 #endif
 
+int __weak cache_setup_acpi(unsigned int cpu)
+{
+	return -ENOTSUPP;
+}
+
 static int cache_shared_cpu_map_setup(unsigned int cpu)
 {
 	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
@@ -227,8 +232,8 @@ static int cache_shared_cpu_map_setup(unsigned int cpu)
 	if (of_have_populated_dt())
 		ret = cache_setup_of_node(cpu);
 	else if (!acpi_disabled)
-		/* No cache property/hierarchy support yet in ACPI */
-		ret = -ENOTSUPP;
+		ret = cache_setup_acpi(cpu);
+
 	if (ret)
 		return ret;
 
@@ -279,7 +284,8 @@ static void cache_shared_cpu_map_remove(unsigned int cpu)
 			cpumask_clear_cpu(cpu, &sib_leaf->shared_cpu_map);
 			cpumask_clear_cpu(sibling, &this_leaf->shared_cpu_map);
 		}
-		of_node_put(this_leaf->fw_token);
+		if (of_have_populated_dt())
+			of_node_put(this_leaf->fw_token);
 	}
 }
 

include/linux/cacheinfo.h

@@ -97,6 +97,23 @@ int func(unsigned int cpu)					\
 struct cpu_cacheinfo *get_cpu_cacheinfo(unsigned int cpu);
 int init_cache_level(unsigned int cpu);
 int populate_cache_leaves(unsigned int cpu);
+int cache_setup_acpi(unsigned int cpu);
+#ifndef CONFIG_ACPI
+/*
+ * acpi_find_last_cache_level is only called on ACPI enabled
+ * platforms using the PPTT for topology. This means that if
+ * the platform supports other firmware configuration methods
+ * we need to stub out the call when ACPI is disabled.
+ * ACPI enabled platforms not using PPTT won't be making calls
+ * to this function so we need not worry about them.
+ */
+static inline int acpi_find_last_cache_level(unsigned int cpu)
+{
+	return 0;
+}
+#else
+int acpi_find_last_cache_level(unsigned int cpu);
+#endif
 
 const struct attribute_group *cache_get_priv_group(struct cacheinfo *this_leaf);