// SPDX-License-Identifier: GPL-2.0
/*
 * Extract CPU cache information and expose them via sysfs.
 *
 *    Copyright IBM Corp. 2012
 */

#include <linux/seq_file.h>
#include <linux/cpu.h>
#include <linux/cacheinfo.h>
#include <asm/facility.h>

enum {
        CACHE_SCOPE_NOTEXISTS,
        CACHE_SCOPE_PRIVATE,
        CACHE_SCOPE_SHARED,
        CACHE_SCOPE_RESERVED,
};

enum {
        CTYPE_SEPARATE,
        CTYPE_DATA,
        CTYPE_INSTRUCTION,
        CTYPE_UNIFIED,
};

enum {
        EXTRACT_TOPOLOGY,
        EXTRACT_LINE_SIZE,
        EXTRACT_SIZE,
        EXTRACT_ASSOCIATIVITY,
};

enum {
        CACHE_TI_UNIFIED = 0,
        CACHE_TI_DATA = 0,
        CACHE_TI_INSTRUCTION,
};

struct cache_info {
        unsigned char       : 4;
        unsigned char scope : 2;
        unsigned char type  : 2;
};

#define CACHE_MAX_LEVEL 8
union cache_topology {
        struct cache_info ci[CACHE_MAX_LEVEL];
        unsigned long raw;
};

static const char * const cache_type_string[] = {
        "",
        "Instruction",
        "Data",
        "",
        "Unified",
};

static const enum cache_type cache_type_map[] = {
        [CTYPE_SEPARATE] = CACHE_TYPE_SEPARATE,
        [CTYPE_DATA] = CACHE_TYPE_DATA,
        [CTYPE_INSTRUCTION] = CACHE_TYPE_INST,
        [CTYPE_UNIFIED] = CACHE_TYPE_UNIFIED,
};

void show_cacheinfo(struct seq_file *m)
{
        struct cpu_cacheinfo *this_cpu_ci;
        struct cacheinfo *cache;
        int idx;

        this_cpu_ci = get_cpu_cacheinfo(cpumask_any(cpu_online_mask));
        for (idx = 0; idx < this_cpu_ci->num_leaves; idx++) {
                cache = this_cpu_ci->info_list + idx;
                seq_printf(m, "cache%-11d: ", idx);
                seq_printf(m, "level=%d ", cache->level);
                seq_printf(m, "type=%s ", cache_type_string[cache->type]);
                seq_printf(m, "scope=%s ",
                           cache->disable_sysfs ? "Shared" : "Private");
                seq_printf(m, "size=%dK ", cache->size >> 10);
                seq_printf(m, "line_size=%u ", cache->coherency_line_size);
                seq_printf(m, "associativity=%d", cache->ways_of_associativity);
                seq_puts(m, "\n");
        }
}

static inline enum cache_type get_cache_type(struct cache_info *ci, int level)
{
        if (level >= CACHE_MAX_LEVEL)
                return CACHE_TYPE_NOCACHE;
        ci += level;
        if (ci->scope != CACHE_SCOPE_SHARED && ci->scope != CACHE_SCOPE_PRIVATE)
                return CACHE_TYPE_NOCACHE;
        return cache_type_map[ci->type];
}

static inline unsigned long ecag(int ai, int li, int ti)
{
        return __ecag(ECAG_CACHE_ATTRIBUTE, ai << 4 | li << 1 | ti);
}

static void ci_leaf_init(struct cacheinfo *this_leaf, int private,
                         enum cache_type type, unsigned int level, int cpu)
{
        int ti, num_sets;

        if (type == CACHE_TYPE_INST)
                ti = CACHE_TI_INSTRUCTION;
        else
                ti = CACHE_TI_UNIFIED;
        this_leaf->level = level + 1;
        this_leaf->type = type;
        this_leaf->coherency_line_size = ecag(EXTRACT_LINE_SIZE, level, ti);
        this_leaf->ways_of_associativity = ecag(EXTRACT_ASSOCIATIVITY, level, ti);
        this_leaf->size = ecag(EXTRACT_SIZE, level, ti);
        num_sets = this_leaf->size / this_leaf->coherency_line_size;
        num_sets /= this_leaf->ways_of_associativity;
        this_leaf->number_of_sets = num_sets;
        cpumask_set_cpu(cpu, &this_leaf->shared_cpu_map);
        if (!private)
                this_leaf->disable_sysfs = true;
}

int init_cache_level(unsigned int cpu)
{
        struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
        unsigned int level = 0, leaves = 0;
        union cache_topology ct;
        enum cache_type ctype;

        if (!this_cpu_ci)
                return -EINVAL;
        ct.raw = ecag(EXTRACT_TOPOLOGY, 0, 0);
        do {
                ctype = get_cache_type(&ct.ci[0], level);
                if (ctype == CACHE_TYPE_NOCACHE)
                        break;
                /* Separate instruction and data caches */
                leaves += (ctype == CACHE_TYPE_SEPARATE) ? 2 : 1;
        } while (++level < CACHE_MAX_LEVEL);
        this_cpu_ci->num_levels = level;
        this_cpu_ci->num_leaves = leaves;
        return 0;
}

int populate_cache_leaves(unsigned int cpu)
{
        struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
        struct cacheinfo *this_leaf = this_cpu_ci->info_list;
        unsigned int level, idx, pvt;
        union cache_topology ct;
        enum cache_type ctype;

        ct.raw = ecag(EXTRACT_TOPOLOGY, 0, 0);
        for (idx = 0, level = 0; level < this_cpu_ci->num_levels &&
             idx < this_cpu_ci->num_leaves; idx++, level++) {
                if (!this_leaf)
                        return -EINVAL;
                pvt = (ct.ci[level].scope == CACHE_SCOPE_PRIVATE) ? 1 : 0;
                ctype = get_cache_type(&ct.ci[0], level);
                if (ctype == CACHE_TYPE_SEPARATE) {
                        ci_leaf_init(this_leaf++, pvt, CACHE_TYPE_DATA, level, cpu);
                        ci_leaf_init(this_leaf++, pvt, CACHE_TYPE_INST, level, cpu);
                } else {
                        ci_leaf_init(this_leaf++, pvt, ctype, level, cpu);
                }
        }
        this_cpu_ci->cpu_map_populated = true;
        return 0;
}