[1/6] ACPI/PPTT: Add Processor Properties Topology Table parsing

diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c
new file mode 100644
index 000000000000..a70b83bd8328
--- /dev/null
+++ b/drivers/acpi/pptt.c
@@ -0,0 +1,507 @@ 
+/*
+ * Copyright (C) 2017, ARM
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * This file implements parsing of Processor Properties Topology Table (PPTT)
+ * which is optionally used to describe the processor and cache topology.
+ * Due to the relative pointers used throughout the table, this doesn't
+ * leverage the existing subtable parsing in the kernel.
+ */
+
+#define pr_fmt(fmt) "ACPI PPTT: " fmt
+
+#include <linux/acpi.h>
+#include <linux/cacheinfo.h>
+#include <acpi/processor.h>
+
+/*
+ * Given the PPTT table, find and verify that the subtable entry
+ * is located within the table
+ */
+static struct acpi_subtable_header *fetch_pptt_subtable(
+	struct acpi_table_header *table_hdr, u32 pptt_ref)
+{
+	struct acpi_subtable_header *entry;
+
+	/* there isn't a subtable at reference 0 */
+	if (!pptt_ref)
+		return NULL;
+
+	if (pptt_ref + sizeof(struct acpi_subtable_header) > table_hdr->length)
+		return NULL;
+
+	entry = (struct acpi_subtable_header *)((u8 *)table_hdr + pptt_ref);
+
+	if (pptt_ref + entry->length > table_hdr->length)
+		return NULL;
+
+	return entry;
+}
+
+static struct acpi_pptt_processor *fetch_pptt_node(
+	struct acpi_table_header *table_hdr, u32 pptt_ref)
+{
+	return (struct acpi_pptt_processor *)fetch_pptt_subtable(table_hdr, pptt_ref);
+}
+
+static struct acpi_pptt_cache *fetch_pptt_cache(
+	struct acpi_table_header *table_hdr, u32 pptt_ref)
+{
+	return (struct acpi_pptt_cache *)fetch_pptt_subtable(table_hdr, pptt_ref);
+}
+
+static struct acpi_subtable_header *acpi_get_pptt_resource(
+	struct acpi_table_header *table_hdr,
+	struct acpi_pptt_processor *node, int resource)
+{
+	u32 ref;
+
+	if (resource >= node->number_of_priv_resources)
+		return NULL;
+
+	ref = *(u32 *)((u8 *)node + sizeof(struct acpi_pptt_processor) +
+		      sizeof(u32) * resource);
+
+	return fetch_pptt_subtable(table_hdr, ref);
+}
+
+/*
+ * given a pptt resource, verify that it is a cache node, then walk
+ * down each level of caches, counting how many levels are found
+ * as well as checking the cache type (icache, dcache, unified). If a
+ * level & type match, then we set found, and continue the search.
+ * Once the entire cache branch has been walked return its max
+ * depth.
+ */
+static int acpi_pptt_walk_cache(struct acpi_table_header *table_hdr,
+				int local_level,
+				struct acpi_subtable_header *res,
+				struct acpi_pptt_cache **found,
+				int level, int type)
+{
+	struct acpi_pptt_cache *cache;
+
+	if (res->type != ACPI_PPTT_TYPE_CACHE)
+		return 0;
+
+	cache = (struct acpi_pptt_cache *) res;
+	while (cache) {
+		local_level++;
+
+		if ((local_level == level) &&
+		    (cache->flags & ACPI_PPTT_CACHE_TYPE_VALID) &&
+		    ((cache->attributes & ACPI_PPTT_MASK_CACHE_TYPE) == type)) {
+			if (*found != NULL)
+				pr_err("Found duplicate cache level/type unable to determine uniqueness\n");
+
+			pr_debug("Found cache @ level %d\n", level);
+			*found = cache;
+			/*
+			 * continue looking at this node's resource list
+			 * to verify that we don't find a duplicate
+			 * cache node.
+			 */
+		}
+		cache = fetch_pptt_cache(table_hdr, cache->next_level_of_cache);
+	}
+	return local_level;
+}
+
+/*
+ * Given a CPU node look for cache levels that exist at this level, and then
+ * for each cache node, count how many levels exist below (logically above) it.
+ * If a level and type are specified, and we find that level/type, abort
+ * processing and return the acpi_pptt_cache structure.
+ */
+static struct acpi_pptt_cache *acpi_find_cache_level(
+	struct acpi_table_header *table_hdr,
+	struct acpi_pptt_processor *cpu_node,
+	int *starting_level, int level, int type)
+{
+	struct acpi_subtable_header *res;
+	int number_of_levels = *starting_level;
+	int resource = 0;
+	struct acpi_pptt_cache *ret = NULL;
+	int local_level;
+
+	/* walk down from processor node */
+	while ((res = acpi_get_pptt_resource(table_hdr, cpu_node, resource))) {
+		resource++;
+
+		local_level = acpi_pptt_walk_cache(table_hdr, *starting_level,
+						   res, &ret, level, type);
+		/*
+		 * we are looking for the max depth. Since its potentially
+		 * possible for a given node to have resources with differing
+		 * depths verify that the depth we have found is the largest.
+		 */
+		if (number_of_levels < local_level)
+			number_of_levels = local_level;
+	}
+	if (number_of_levels > *starting_level)
+		*starting_level = number_of_levels;
+
+	return ret;
+}
+
+/*
+ * given a processor node containing a processing unit, walk into it and count
+ * how many levels exist solely for it, and then walk up each level until we hit
+ * the root node (ignore the package level because it may be possible to have
+ * caches that exist across packages). Count the number of cache levels that
+ * exist at each level on the way up.
+ */
+static int acpi_process_node(struct acpi_table_header *table_hdr,
+			     struct acpi_pptt_processor *cpu_node)
+{
+	int total_levels = 0;
+
+	do {
+		acpi_find_cache_level(table_hdr, cpu_node, &total_levels, 0, 0);
+		cpu_node = fetch_pptt_node(table_hdr, cpu_node->parent);
+	} while (cpu_node);
+
+	return total_levels;
+}
+
+/*
+ * Find the subtable entry describing the provided processor
+ */
+static struct acpi_pptt_processor *acpi_find_processor_node(
+	struct acpi_table_header *table_hdr,
+	u32 acpi_cpu_id)
+{
+	struct acpi_subtable_header *entry;
+	unsigned long table_end;
+	struct acpi_pptt_processor *cpu_node;
+
+	table_end = (unsigned long)table_hdr + table_hdr->length;
+	entry = (struct acpi_subtable_header *)((u8 *)table_hdr +
+						sizeof(struct acpi_table_pptt));
+
+	/* find the processor structure associated with this cpuid */
+	while (((unsigned long)entry) + sizeof(struct acpi_subtable_header) < table_end) {
+		cpu_node = (struct acpi_pptt_processor *)entry;
+
+		if ((entry->type == ACPI_PPTT_TYPE_PROCESSOR) &&
+		    (cpu_node->flags & ACPI_PPTT_ACPI_PROCESSOR_ID_VALID)) {
+			pr_debug("checking phy_cpu_id %d against acpi id %d\n",
+				 acpi_cpu_id, cpu_node->acpi_processor_id);
+			if (acpi_cpu_id == cpu_node->acpi_processor_id) {
+				/* found the correct entry */
+				pr_debug("match found!\n");
+				return (struct acpi_pptt_processor *)entry;
+			}
+		}
+
+		if (entry->length == 0) {
+			pr_err("Invalid zero length subtable\n");
+			break;
+		}
+		entry = (struct acpi_subtable_header *)
+			((u8 *)entry + entry->length);
+	}
+
+	return NULL;
+}
+
+/*
+ * Count the total number of processor nodes that are marked as physical
+ * packages. This should equal the number of sockets in the machine.
+ */
+static int acpi_count_socket_nodes(struct acpi_table_header *table_hdr)
+{
+	struct acpi_subtable_header *entry;
+	unsigned long table_end;
+	struct acpi_pptt_processor *cpu_node;
+	int number_of_sockets = 0;
+
+	table_end = (unsigned long)table_hdr + table_hdr->length;
+	entry = (struct acpi_subtable_header *)((u8 *)table_hdr +
+						sizeof(struct acpi_table_pptt));
+
+	/* count processor structures with PHYSICAL_PACKAGE set */
+	while (((unsigned long)entry) + sizeof(struct acpi_subtable_header) < table_end) {
+		cpu_node = (struct acpi_pptt_processor *)entry;
+
+		if ((entry->type == ACPI_PPTT_TYPE_PROCESSOR) &&
+		    (cpu_node->flags & ACPI_PPTT_PHYSICAL_PACKAGE))
+			number_of_sockets++;
+
+		if (entry->length == 0) {
+			pr_err("Invalid zero length subtable\n");
+			break;
+		}
+		entry = (struct acpi_subtable_header *)
+			((u8 *)entry + entry->length);
+	}
+
+	return number_of_sockets;
+}
+
+
+/*
+ * Given a acpi_pptt_processor node, walk up until we identify the
+ * package that the node is associated with or we run out of levels
+ * to request.
+ */
+static struct acpi_pptt_processor *acpi_find_processor_package_id(
+	struct acpi_table_header *table_hdr,
+	struct acpi_pptt_processor *cpu,
+	int level)
+{
+	struct acpi_pptt_processor *prev_node;
+
+	while (cpu && level && !(cpu->flags & ACPI_PPTT_PHYSICAL_PACKAGE)) {
+		pr_debug("level %d\n", level);
+		prev_node = fetch_pptt_node(table_hdr, cpu->parent);
+		if (prev_node == NULL)
+			break;
+		cpu = prev_node;
+		level--;
+	}
+	return cpu;
+}
+
+static int acpi_parse_pptt(struct acpi_table_header *table_hdr, u32 acpi_cpu_id)
+{
+	int number_of_levels = 0;
+	struct acpi_pptt_processor *cpu;
+
+	cpu = acpi_find_processor_node(table_hdr, acpi_cpu_id);
+	if (cpu)
+		number_of_levels = acpi_process_node(table_hdr, cpu);
+
+	return number_of_levels;
+}
+
+#define ACPI_6_2_CACHE_TYPE_DATA		      (0x0)
+#define ACPI_6_2_CACHE_TYPE_INSTR		      (1<<2)
+#define ACPI_6_2_CACHE_TYPE_UNIFIED		      (1<<3)
+#define ACPI_6_2_CACHE_POLICY_WB		      (0x0)
+#define ACPI_6_2_CACHE_POLICY_WT		      (1<<4)
+#define ACPI_6_2_CACHE_READ_ALLOCATE		      (0x0)
+#define ACPI_6_2_CACHE_WRITE_ALLOCATE		      (0x01)
+#define ACPI_6_2_CACHE_RW_ALLOCATE		      (0x02)
+
+static u8 acpi_cache_type(enum cache_type type)
+{
+	switch (type) {
+	case CACHE_TYPE_DATA:
+		pr_debug("Looking for data cache\n");
+		return ACPI_6_2_CACHE_TYPE_DATA;
+	case CACHE_TYPE_INST:
+		pr_debug("Looking for instruction cache\n");
+		return ACPI_6_2_CACHE_TYPE_INSTR;
+	default:
+		pr_debug("Unknown cache type, assume unified\n");
+	case CACHE_TYPE_UNIFIED:
+		pr_debug("Looking for unified cache\n");
+		return ACPI_6_2_CACHE_TYPE_UNIFIED;
+	}
+}
+
+/* find the ACPI node describing the cache type/level for the given CPU */
+static struct acpi_pptt_cache *acpi_find_cache_node(
+	struct acpi_table_header *table_hdr, u32 acpi_cpu_id,
+	enum cache_type type, unsigned int level)
+{
+	int total_levels = 0;
+	struct acpi_pptt_cache *found = NULL;
+	struct acpi_pptt_processor *cpu_node;
+	u8 acpi_type = acpi_cache_type(type);
+
+	pr_debug("Looking for CPU %d's level %d cache type %d\n",
+		 acpi_cpu_id, level, acpi_type);
+
+	cpu_node = acpi_find_processor_node(table_hdr, acpi_cpu_id);
+	if (!cpu_node)
+		return NULL;
+
+	do {
+		found = acpi_find_cache_level(table_hdr, cpu_node, &total_levels, level, acpi_type);
+		cpu_node = fetch_pptt_node(table_hdr, cpu_node->parent);
+	} while ((cpu_node) && (!found));
+
+	return found;
+}
+
+int acpi_find_last_cache_level(unsigned int cpu)
+{
+	u32 acpi_cpu_id;
+	struct acpi_table_header *table;
+	int number_of_levels = 0;
+	acpi_status status;
+
+	pr_debug("Cache Setup find last level cpu=%d\n", cpu);
+
+	acpi_cpu_id = acpi_cpu_get_madt_gicc(cpu)->uid;
+	status = acpi_get_table(ACPI_SIG_PPTT, 0, &table);
+	if (ACPI_FAILURE(status)) {
+		pr_err_once("No PPTT table found, cache topology may be inaccurate\n");
+	} else {
+		number_of_levels = acpi_parse_pptt(table, acpi_cpu_id);
+		acpi_put_table(table);
+	}
+	pr_debug("Cache Setup find last level level=%d\n", number_of_levels);
+
+	return number_of_levels;
+}
+
+/*
+ * The ACPI spec implies that the fields in the cache structures are used to
+ * extend and correct the information probed from the hardware. In the case
+ * of arm64 the CCSIDR probing has been removed because it might be incorrect.
+ */
+static void update_cache_properties(struct cacheinfo *this_leaf,
+				    struct acpi_pptt_cache *found_cache)
+{
+	if (found_cache->flags & ACPI_PPTT_SIZE_PROPERTY_VALID)
+		this_leaf->size = found_cache->size;
+	if (found_cache->flags & ACPI_PPTT_LINE_SIZE_VALID)
+		this_leaf->coherency_line_size = found_cache->line_size;
+	if (found_cache->flags & ACPI_PPTT_NUMBER_OF_SETS_VALID)
+		this_leaf->number_of_sets = found_cache->number_of_sets;
+	if (found_cache->flags & ACPI_PPTT_ASSOCIATIVITY_VALID)
+		this_leaf->ways_of_associativity = found_cache->associativity;
+	if (found_cache->flags & ACPI_PPTT_WRITE_POLICY_VALID)
+		switch (found_cache->attributes & ACPI_PPTT_MASK_WRITE_POLICY) {
+		case ACPI_6_2_CACHE_POLICY_WT:
+			this_leaf->attributes = CACHE_WRITE_THROUGH;
+			break;
+		case ACPI_6_2_CACHE_POLICY_WB:
+			this_leaf->attributes = CACHE_WRITE_BACK;
+			break;
+		default:
+			pr_err("Unknown ACPI cache policy %d\n",
+			      found_cache->attributes & ACPI_PPTT_MASK_WRITE_POLICY);
+		}
+	if (found_cache->flags & ACPI_PPTT_ALLOCATION_TYPE_VALID)
+		switch (found_cache->attributes & ACPI_PPTT_MASK_ALLOCATION_TYPE) {
+		case ACPI_6_2_CACHE_READ_ALLOCATE:
+			this_leaf->attributes |= CACHE_READ_ALLOCATE;
+			break;
+		case ACPI_6_2_CACHE_WRITE_ALLOCATE:
+			this_leaf->attributes |= CACHE_WRITE_ALLOCATE;
+			break;
+		case ACPI_6_2_CACHE_RW_ALLOCATE:
+			this_leaf->attributes |=
+				CACHE_READ_ALLOCATE|CACHE_WRITE_ALLOCATE;
+			break;
+		default:
+			pr_err("Unknown ACPI cache allocation policy %d\n",
+			   found_cache->attributes & ACPI_PPTT_MASK_ALLOCATION_TYPE);
+		}
+}
+
+static void cache_setup_acpi_cpu(struct acpi_table_header *table,
+				 unsigned int cpu)
+{
+	struct acpi_pptt_cache *found_cache;
+	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
+	u32 acpi_cpu_id = acpi_cpu_get_madt_gicc(cpu)->uid;
+	struct cacheinfo *this_leaf;
+	unsigned int index = 0;
+
+	while (index < get_cpu_cacheinfo(cpu)->num_leaves) {
+		this_leaf = this_cpu_ci->info_list + index;
+		found_cache = acpi_find_cache_node(table, acpi_cpu_id,
+						   this_leaf->type,
+						   this_leaf->level);
+		pr_debug("found = %p\n", found_cache);
+		if (found_cache)
+			update_cache_properties(this_leaf, found_cache);
+
+		index++;
+	}
+}
+
+static int topology_setup_acpi_cpu(struct acpi_table_header *table,
+				    unsigned int cpu, int level)
+{
+	struct acpi_pptt_processor *cpu_node;
+	u32 acpi_cpu_id = acpi_cpu_get_madt_gicc(cpu)->uid;
+
+	cpu_node = acpi_find_processor_node(table, acpi_cpu_id);
+	if (cpu_node) {
+		cpu_node = acpi_find_processor_package_id(table, cpu_node, level);
+		return (int)((u8 *)cpu_node - (u8 *)table);
+	}
+	pr_err_once("PPTT table found, but unable to locate core for %d\n",
+		    cpu);
+	return -ENOENT;
+}
+
+/*
+ * simply assign a ACPI cache entry to each known CPU cache entry
+ * determining which entries are shared is done later.
+ */
+int cache_setup_acpi(unsigned int cpu)
+{
+	struct acpi_table_header *table;
+	acpi_status status;
+
+	pr_debug("Cache Setup ACPI cpu %d\n", cpu);
+
+	status = acpi_get_table(ACPI_SIG_PPTT, 0, &table);
+	if (ACPI_FAILURE(status)) {
+		pr_err_once("No PPTT table found, cache topology may be inaccurate\n");
+		return -ENOENT;
+	}
+
+	cache_setup_acpi_cpu(table, cpu);
+	acpi_put_table(table);
+
+	return status;
+}
+
+/*
+ * Determine a topology unique ID for each thread/core/cluster/socket/etc.
+ * This ID can then be used to group peers.
+ */
+int setup_acpi_cpu_topology(unsigned int cpu, int level)
+{
+	struct acpi_table_header *table;
+	acpi_status status;
+	int retval;
+
+	status = acpi_get_table(ACPI_SIG_PPTT, 0, &table);
+	if (ACPI_FAILURE(status)) {
+		pr_err_once("No PPTT table found, cpu topology may be inaccurate\n");
+		return -ENOENT;
+	}
+	retval = topology_setup_acpi_cpu(table, cpu, level);
+	pr_debug("Topology Setup ACPI cpu %d, level %d ret = %d\n",
+		 cpu, level, retval);
+	acpi_put_table(table);
+
+	return retval;
+}
+
+/*
+ * Walk the PPTT, count the number of sockets we detect
+ */
+int acpi_multisocket_count(void)
+{
+	struct acpi_table_header *table;
+	acpi_status status;
+	int retval = 0;
+
+	status = acpi_get_table(ACPI_SIG_PPTT, 0, &table);
+	if (ACPI_FAILURE(status)) {
+		pr_err_once("No PPTT table found, socket topology may be inaccurate\n");
+		return -ENOENT;
+	}
+	retval = acpi_count_socket_nodes(table);
+	acpi_put_table(table);
+
+	return retval;
+}