// SPDX-License-Identifier: MIT
/*
 * Copyright © 2019 Intel Corporation
 */

#include <linux/list.h>
#include <linux/list_sort.h>
#include <linux/llist.h>

#include <drm/drm_print.h>

#include "i915_drv.h"
#include "intel_engine.h"
#include "intel_engine_user.h"
#include "intel_gt.h"
#include "uc/intel_guc_submission.h"

struct intel_engine_cs *
intel_engine_lookup_user(struct drm_i915_private *i915, u8 class, u8 instance)
{
        struct rb_node *p = i915->uabi_engines.rb_node;

        while (p) {
                struct intel_engine_cs *it =
                        rb_entry(p, typeof(*it), uabi_node);

                if (class < it->uabi_class)
                        p = p->rb_left;
                else if (class > it->uabi_class ||
                         instance > it->uabi_instance)
                        p = p->rb_right;
                else if (instance < it->uabi_instance)
                        p = p->rb_left;
                else
                        return it;
        }

        return NULL;
}

void intel_engine_add_user(struct intel_engine_cs *engine)
{
        llist_add(&engine->uabi_llist, &engine->i915->uabi_engines_llist);
}

#define I915_NO_UABI_CLASS ((u16)(-1))

static const u16 uabi_classes[] = {
        [RENDER_CLASS] = I915_ENGINE_CLASS_RENDER,
        [COPY_ENGINE_CLASS] = I915_ENGINE_CLASS_COPY,
        [VIDEO_DECODE_CLASS] = I915_ENGINE_CLASS_VIDEO,
        [VIDEO_ENHANCEMENT_CLASS] = I915_ENGINE_CLASS_VIDEO_ENHANCE,
        [COMPUTE_CLASS] = I915_ENGINE_CLASS_COMPUTE,
        [OTHER_CLASS] = I915_NO_UABI_CLASS, /* Not exposed to users, no uabi class. */
};

static int engine_cmp(void *priv, const struct list_head *A,
                      const struct list_head *B)
{
        const struct intel_engine_cs *a =
                container_of(A, typeof(*a), uabi_list);
        const struct intel_engine_cs *b =
                container_of(B, typeof(*b), uabi_list);

        if (uabi_classes[a->class] < uabi_classes[b->class])
                return -1;
        if (uabi_classes[a->class] > uabi_classes[b->class])
                return 1;

        if (a->instance < b->instance)
                return -1;
        if (a->instance > b->instance)
                return 1;

        return 0;
}

static struct llist_node *get_engines(struct drm_i915_private *i915)
{
        return llist_del_all(&i915->uabi_engines_llist);
}

static void sort_engines(struct drm_i915_private *i915,
                         struct list_head *engines)
{
        struct llist_node *pos, *next;

        llist_for_each_safe(pos, next, get_engines(i915)) {
                struct intel_engine_cs *engine =
                        container_of(pos, typeof(*engine), uabi_llist);
                list_add(&engine->uabi_list, engines);
        }
        list_sort(NULL, engines, engine_cmp);
}

static void set_scheduler_caps(struct drm_i915_private *i915)
{
        static const struct {
                u8 engine;
                u8 sched;
        } map[] = {
#define MAP(x, y) { ilog2(I915_ENGINE_##x), ilog2(I915_SCHEDULER_CAP_##y) }
                MAP(HAS_PREEMPTION, PREEMPTION),
                MAP(HAS_SEMAPHORES, SEMAPHORES),
                MAP(SUPPORTS_STATS, ENGINE_BUSY_STATS),
#undef MAP
        };
        struct intel_engine_cs *engine;
        u32 enabled, disabled;

        enabled = 0;
        disabled = 0;
        for_each_uabi_engine(engine, i915) { /* all engines must agree! */
                int i;

                if (engine->sched_engine->schedule)
                        enabled |= (I915_SCHEDULER_CAP_ENABLED |
                                    I915_SCHEDULER_CAP_PRIORITY);
                else
                        disabled |= (I915_SCHEDULER_CAP_ENABLED |
                                     I915_SCHEDULER_CAP_PRIORITY);

                if (intel_uc_uses_guc_submission(&engine->gt->uc))
                        enabled |= I915_SCHEDULER_CAP_STATIC_PRIORITY_MAP;

                for (i = 0; i < ARRAY_SIZE(map); i++) {
                        if (engine->flags & BIT(map[i].engine))
                                enabled |= BIT(map[i].sched);
                        else
                                disabled |= BIT(map[i].sched);
                }
        }

        i915->caps.scheduler = enabled & ~disabled;
        if (!(i915->caps.scheduler & I915_SCHEDULER_CAP_ENABLED))
                i915->caps.scheduler = 0;
}

const char *intel_engine_class_repr(u8 class)
{
        static const char * const uabi_names[] = {
                [RENDER_CLASS] = "rcs",
                [COPY_ENGINE_CLASS] = "bcs",
                [VIDEO_DECODE_CLASS] = "vcs",
                [VIDEO_ENHANCEMENT_CLASS] = "vecs",
                [OTHER_CLASS] = "other",
                [COMPUTE_CLASS] = "ccs",
        };

        if (class >= ARRAY_SIZE(uabi_names) || !uabi_names[class])
                return "xxx";

        return uabi_names[class];
}

struct legacy_ring {
        struct intel_gt *gt;
        u8 class;
        u8 instance;
};

static int legacy_ring_idx(const struct legacy_ring *ring)
{
        static const struct {
                u8 base, max;
        } map[] = {
                [RENDER_CLASS] = { RCS0, 1 },
                [COPY_ENGINE_CLASS] = { BCS0, 1 },
                [VIDEO_DECODE_CLASS] = { VCS0, I915_MAX_VCS },
                [VIDEO_ENHANCEMENT_CLASS] = { VECS0, I915_MAX_VECS },
                [COMPUTE_CLASS] = { CCS0, I915_MAX_CCS },
        };

        if (GEM_DEBUG_WARN_ON(ring->class >= ARRAY_SIZE(map)))
                return INVALID_ENGINE;

        if (GEM_DEBUG_WARN_ON(ring->instance >= map[ring->class].max))
                return INVALID_ENGINE;

        return map[ring->class].base + ring->instance;
}

static void add_legacy_ring(struct legacy_ring *ring,
                            struct intel_engine_cs *engine)
{
        if (engine->gt != ring->gt || engine->class != ring->class) {
                ring->gt = engine->gt;
                ring->class = engine->class;
                ring->instance = 0;
        }

        engine->legacy_idx = legacy_ring_idx(ring);
        if (engine->legacy_idx != INVALID_ENGINE)
                ring->instance++;
}

static void engine_rename(struct intel_engine_cs *engine, const char *name, u16 instance)
{
        char old[sizeof(engine->name)];

        memcpy(old, engine->name, sizeof(engine->name));
        scnprintf(engine->name, sizeof(engine->name), "%s%u", name, instance);
        drm_dbg(&engine->i915->drm, "renamed %s to %s\n", old, engine->name);
}

void intel_engines_driver_register(struct drm_i915_private *i915)
{
        u16 name_instance, other_instance = 0;
        struct legacy_ring ring = {};
        struct list_head *it, *next;
        struct rb_node **p, *prev;
        LIST_HEAD(engines);

        sort_engines(i915, &engines);

        prev = NULL;
        p = &i915->uabi_engines.rb_node;
        list_for_each_safe(it, next, &engines) {
                struct intel_engine_cs *engine =
                        container_of(it, typeof(*engine), uabi_list);

                if (intel_gt_has_unrecoverable_error(engine->gt))
                        continue; /* ignore incomplete engines */

                GEM_BUG_ON(engine->class >= ARRAY_SIZE(uabi_classes));
                engine->uabi_class = uabi_classes[engine->class];
                if (engine->uabi_class == I915_NO_UABI_CLASS) {
                        name_instance = other_instance++;
                } else {
                        GEM_BUG_ON(engine->uabi_class >=
                                   ARRAY_SIZE(i915->engine_uabi_class_count));
                        name_instance =
                                i915->engine_uabi_class_count[engine->uabi_class]++;
                }
                engine->uabi_instance = name_instance;

                /*
                 * Replace the internal name with the final user and log facing
                 * name.
                 */
                engine_rename(engine,
                              intel_engine_class_repr(engine->class),
                              name_instance);

                if (engine->uabi_class == I915_NO_UABI_CLASS)
                        continue;

                rb_link_node(&engine->uabi_node, prev, p);
                rb_insert_color(&engine->uabi_node, &i915->uabi_engines);

                GEM_BUG_ON(intel_engine_lookup_user(i915,
                                                    engine->uabi_class,
                                                    engine->uabi_instance) != engine);

                /* Fix up the mapping to match default execbuf::user_map[] */
                add_legacy_ring(&ring, engine);

                prev = &engine->uabi_node;
                p = &prev->rb_right;
        }

        if (IS_ENABLED(CONFIG_DRM_I915_SELFTESTS) &&
            IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)) {
                struct intel_engine_cs *engine;
                unsigned int isolation;
                int class, inst;
                int errors = 0;

                for (class = 0; class < ARRAY_SIZE(i915->engine_uabi_class_count); class++) {
                        for (inst = 0; inst < i915->engine_uabi_class_count[class]; inst++) {
                                engine = intel_engine_lookup_user(i915,
                                                                  class, inst);
                                if (!engine) {
                                        pr_err("UABI engine not found for { class:%d, instance:%d }\n",
                                               class, inst);
                                        errors++;
                                        continue;
                                }

                                if (engine->uabi_class != class ||
                                    engine->uabi_instance != inst) {
                                        pr_err("Wrong UABI engine:%s { class:%d, instance:%d } found for { class:%d, instance:%d }\n",
                                               engine->name,
                                               engine->uabi_class,
                                               engine->uabi_instance,
                                               class, inst);
                                        errors++;
                                        continue;
                                }
                        }
                }

                /*
                 * Make sure that classes with multiple engine instances all
                 * share the same basic configuration.
                 */
                isolation = intel_engines_has_context_isolation(i915);
                for_each_uabi_engine(engine, i915) {
                        unsigned int bit = BIT(engine->uabi_class);
                        unsigned int expected = engine->default_state ? bit : 0;

                        if ((isolation & bit) != expected) {
                                pr_err("mismatching default context state for class %d on engine %s\n",
                                       engine->uabi_class, engine->name);
                                errors++;
                        }
                }

                if (drm_WARN(&i915->drm, errors,
                             "Invalid UABI engine mapping found"))
                        i915->uabi_engines = RB_ROOT;
        }

        set_scheduler_caps(i915);
}

unsigned int intel_engines_has_context_isolation(struct drm_i915_private *i915)
{
        struct intel_engine_cs *engine;
        unsigned int which;

        which = 0;
        for_each_uabi_engine(engine, i915)
                if (engine->default_state)
                        which |= BIT(engine->uabi_class);

        return which;
}