/*
 * Copyright © 2017 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 */

#include "../i915_selftest.h"
#include "i915_random.h"

static char *
__sync_print(struct i915_syncmap *p,
             char *buf, unsigned long *sz,
             unsigned int depth,
             unsigned int last,
             unsigned int idx)
{
        unsigned long len;
        unsigned int i, X;

        if (depth) {
                unsigned int d;

                for (d = 0; d < depth - 1; d++) {
                        if (last & BIT(depth - d - 1))
                                len = scnprintf(buf, *sz, "|   ");
                        else
                                len = scnprintf(buf, *sz, "    ");
                        buf += len;
                        *sz -= len;
                }
                len = scnprintf(buf, *sz, "%x-> ", idx);
                buf += len;
                *sz -= len;
        }

        /* We mark bits after the prefix as "X" */
        len = scnprintf(buf, *sz, "0x%016llx", p->prefix << p->height << SHIFT);
        buf += len;
        *sz -= len;
        X = (p->height + SHIFT) / 4;
        scnprintf(buf - X, *sz + X, "%*s", X, "XXXXXXXXXXXXXXXXX");

        if (!p->height) {
                for_each_set_bit(i, (unsigned long *)&p->bitmap, KSYNCMAP) {
                        len = scnprintf(buf, *sz, " %x:%x,",
                                        i, __sync_seqno(p)[i]);
                        buf += len;
                        *sz -= len;
                }
                buf -= 1;
                *sz += 1;
        }

        len = scnprintf(buf, *sz, "\n");
        buf += len;
        *sz -= len;

        if (p->height) {
                for_each_set_bit(i, (unsigned long *)&p->bitmap, KSYNCMAP) {
                        buf = __sync_print(__sync_child(p)[i], buf, sz,
                                           depth + 1,
                                           last << 1 | !!(p->bitmap >> (i + 1)),
                                           i);
                }
        }

        return buf;
}

static bool
i915_syncmap_print_to_buf(struct i915_syncmap *p, char *buf, unsigned long sz)
{
        if (!p)
                return false;

        while (p->parent)
                p = p->parent;

        __sync_print(p, buf, &sz, 0, 1, 0);
        return true;
}

static int check_syncmap_free(struct i915_syncmap **sync)
{
        i915_syncmap_free(sync);
        if (*sync) {
                pr_err("sync not cleared after free\n");
                return -EINVAL;
        }

        return 0;
}

static int dump_syncmap(struct i915_syncmap *sync, int err)
{
        char *buf;

        if (!err)
                return check_syncmap_free(&sync);

        buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
        if (!buf)
                goto skip;

        if (i915_syncmap_print_to_buf(sync, buf, PAGE_SIZE))
                pr_err("%s", buf);

        kfree(buf);

skip:
        i915_syncmap_free(&sync);
        return err;
}

static int igt_syncmap_init(void *arg)
{
        struct i915_syncmap *sync = (void *)~0ul;

        /*
         * Cursory check that we can initialise a random pointer and transform
         * it into the root pointer of a syncmap.
         */

        i915_syncmap_init(&sync);
        return check_syncmap_free(&sync);
}

static int check_seqno(struct i915_syncmap *leaf, unsigned int idx, u32 seqno)
{
        if (leaf->height) {
                pr_err("%s: not a leaf, height is %d\n",
                       __func__, leaf->height);
                return -EINVAL;
        }

        if (__sync_seqno(leaf)[idx] != seqno) {
                pr_err("%s: seqno[%d], found %x, expected %x\n",
                       __func__, idx, __sync_seqno(leaf)[idx], seqno);
                return -EINVAL;
        }

        return 0;
}

static int check_one(struct i915_syncmap **sync, u64 context, u32 seqno)
{
        int err;

        err = i915_syncmap_set(sync, context, seqno);
        if (err)
                return err;

        if ((*sync)->height) {
                pr_err("Inserting first context=%llx did not return leaf (height=%d, prefix=%llx\n",
                       context, (*sync)->height, (*sync)->prefix);
                return -EINVAL;
        }

        if ((*sync)->parent) {
                pr_err("Inserting first context=%llx created branches!\n",
                       context);
                return -EINVAL;
        }

        if (hweight32((*sync)->bitmap) != 1) {
                pr_err("First bitmap does not contain a single entry, found %x (count=%d)!\n",
                       (*sync)->bitmap, hweight32((*sync)->bitmap));
                return -EINVAL;
        }

        err = check_seqno((*sync), ilog2((*sync)->bitmap), seqno);
        if (err)
                return err;

        if (!i915_syncmap_is_later(sync, context, seqno)) {
                pr_err("Lookup of first context=%llx/seqno=%x failed!\n",
                       context, seqno);
                return -EINVAL;
        }

        return 0;
}

static int igt_syncmap_one(void *arg)
{
        I915_RND_STATE(prng);
        IGT_TIMEOUT(end_time);
        struct i915_syncmap *sync;
        unsigned long max = 1;
        int err;

        /*
         * Check that inserting a new id, creates a leaf and only that leaf.
         */

        i915_syncmap_init(&sync);

        do {
                u64 context = i915_prandom_u64_state(&prng);
                unsigned long loop;

                err = check_syncmap_free(&sync);
                if (err)
                        goto out;

                for (loop = 0; loop <= max; loop++) {
                        err = check_one(&sync, context,
                                        prandom_u32_state(&prng));
                        if (err)
                                goto out;
                }
                max++;
        } while (!__igt_timeout(end_time, NULL));
        pr_debug("%s: Completed %lu single insertions\n",
                 __func__, max * (max - 1) / 2);
out:
        return dump_syncmap(sync, err);
}

static int check_leaf(struct i915_syncmap **sync, u64 context, u32 seqno)
{
        int err;

        err = i915_syncmap_set(sync, context, seqno);
        if (err)
                return err;

        if ((*sync)->height) {
                pr_err("Inserting context=%llx did not return leaf (height=%d, prefix=%llx\n",
                       context, (*sync)->height, (*sync)->prefix);
                return -EINVAL;
        }

        if (hweight32((*sync)->bitmap) != 1) {
                pr_err("First entry into leaf (context=%llx) does not contain a single entry, found %x (count=%d)!\n",
                       context, (*sync)->bitmap, hweight32((*sync)->bitmap));
                return -EINVAL;
        }

        err = check_seqno((*sync), ilog2((*sync)->bitmap), seqno);
        if (err)
                return err;

        if (!i915_syncmap_is_later(sync, context, seqno)) {
                pr_err("Lookup of first entry context=%llx/seqno=%x failed!\n",
                       context, seqno);
                return -EINVAL;
        }

        return 0;
}

static int igt_syncmap_join_above(void *arg)
{
        struct i915_syncmap *sync;
        unsigned int pass, order;
        int err;

        i915_syncmap_init(&sync);

        /*
         * When we have a new id that doesn't fit inside the existing tree,
         * we need to add a new layer above.
         *
         * 1: 0x00000001
         * 2: 0x00000010
         * 3: 0x00000100
         * 4: 0x00001000
         * ...
         * Each pass the common prefix shrinks and we have to insert a join.
         * Each join will only contain two branches, the latest of which
         * is always a leaf.
         *
         * If we then reuse the same set of contexts, we expect to build an
         * identical tree.
         */
        for (pass = 0; pass < 3; pass++) {
                for (order = 0; order < 64; order += SHIFT) {
                        u64 context = BIT_ULL(order);
                        struct i915_syncmap *join;

                        err = check_leaf(&sync, context, 0);
                        if (err)
                                goto out;

                        join = sync->parent;
                        if (!join) /* very first insert will have no parents */
                                continue;

                        if (!join->height) {
                                pr_err("Parent with no height!\n");
                                err = -EINVAL;
                                goto out;
                        }

                        if (hweight32(join->bitmap) != 2) {
                                pr_err("Join does not have 2 children: %x (%d)\n",
                                       join->bitmap, hweight32(join->bitmap));
                                err = -EINVAL;
                                goto out;
                        }

                        if (__sync_child(join)[__sync_branch_idx(join, context)] != sync) {
                                pr_err("Leaf misplaced in parent!\n");
                                err = -EINVAL;
                                goto out;
                        }
                }
        }
out:
        return dump_syncmap(sync, err);
}

static int igt_syncmap_join_below(void *arg)
{
        struct i915_syncmap *sync;
        unsigned int step, order, idx;
        int err = -ENODEV;

        i915_syncmap_init(&sync);

        /*
         * Check that we can split a compacted branch by replacing it with
         * a join.
         */
        for (step = 0; step < KSYNCMAP; step++) {
                for (order = 64 - SHIFT; order > 0; order -= SHIFT) {
                        u64 context = step * BIT_ULL(order);

                        err = i915_syncmap_set(&sync, context, 0);
                        if (err)
                                goto out;

                        if (sync->height) {
                                pr_err("Inserting context=%llx (order=%d, step=%d) did not return leaf (height=%d, prefix=%llx\n",
                                       context, order, step, sync->height, sync->prefix);
                                err = -EINVAL;
                                goto out;
                        }
                }
        }

        for (step = 0; step < KSYNCMAP; step++) {
                for (order = SHIFT; order < 64; order += SHIFT) {
                        u64 context = step * BIT_ULL(order);

                        if (!i915_syncmap_is_later(&sync, context, 0)) {
                                pr_err("1: context %llx (order=%d, step=%d) not found\n",
                                       context, order, step);
                                err = -EINVAL;
                                goto out;
                        }

                        for (idx = 1; idx < KSYNCMAP; idx++) {
                                if (i915_syncmap_is_later(&sync, context + idx, 0)) {
                                        pr_err("1: context %llx (order=%d, step=%d) should not exist\n",
                                               context + idx, order, step);
                                        err = -EINVAL;
                                        goto out;
                                }
                        }
                }
        }

        for (order = SHIFT; order < 64; order += SHIFT) {
                for (step = 0; step < KSYNCMAP; step++) {
                        u64 context = step * BIT_ULL(order);

                        if (!i915_syncmap_is_later(&sync, context, 0)) {
                                pr_err("2: context %llx (order=%d, step=%d) not found\n",
                                       context, order, step);
                                err = -EINVAL;
                                goto out;
                        }
                }
        }

out:
        return dump_syncmap(sync, err);
}

static int igt_syncmap_neighbours(void *arg)
{
        I915_RND_STATE(prng);
        IGT_TIMEOUT(end_time);
        struct i915_syncmap *sync;
        int err = -ENODEV;

        /*
         * Each leaf holds KSYNCMAP seqno. Check that when we create KSYNCMAP
         * neighbouring ids, they all fit into the same leaf.
         */

        i915_syncmap_init(&sync);
        do {
                u64 context = i915_prandom_u64_state(&prng) & ~MASK;
                unsigned int idx;

                if (i915_syncmap_is_later(&sync, context, 0)) /* Skip repeats */
                        continue;

                for (idx = 0; idx < KSYNCMAP; idx++) {
                        err = i915_syncmap_set(&sync, context + idx, 0);
                        if (err)
                                goto out;

                        if (sync->height) {
                                pr_err("Inserting context=%llx did not return leaf (height=%d, prefix=%llx\n",
                                       context, sync->height, sync->prefix);
                                err = -EINVAL;
                                goto out;
                        }

                        if (sync->bitmap != BIT(idx + 1) - 1) {
                                pr_err("Inserting neighbouring context=0x%llx+%d, did not fit into the same leaf bitmap=%x (%d), expected %lx (%d)\n",
                                       context, idx,
                                       sync->bitmap, hweight32(sync->bitmap),
                                       BIT(idx + 1) - 1, idx + 1);
                                err = -EINVAL;
                                goto out;
                        }
                }
        } while (!__igt_timeout(end_time, NULL));
out:
        return dump_syncmap(sync, err);
}

static int igt_syncmap_compact(void *arg)
{
        struct i915_syncmap *sync;
        unsigned int idx, order;
        int err = -ENODEV;

        i915_syncmap_init(&sync);

        /*
         * The syncmap are "space efficient" compressed radix trees - any
         * branch with only one child is skipped and replaced by the child.
         *
         * If we construct a tree with ids that are neighbouring at a non-zero
         * height, we form a join but each child of that join is directly a
         * leaf holding the single id.
         */
        for (order = SHIFT; order < 64; order += SHIFT) {
                err = check_syncmap_free(&sync);
                if (err)
                        goto out;

                /* Create neighbours in the parent */
                for (idx = 0; idx < KSYNCMAP; idx++) {
                        u64 context = idx * BIT_ULL(order) + idx;

                        err = i915_syncmap_set(&sync, context, 0);
                        if (err)
                                goto out;

                        if (sync->height) {
                                pr_err("Inserting context=%llx (order=%d, idx=%d) did not return leaf (height=%d, prefix=%llx\n",
                                       context, order, idx,
                                       sync->height, sync->prefix);
                                err = -EINVAL;
                                goto out;
                        }
                }

                sync = sync->parent;
                if (sync->parent) {
                        pr_err("Parent (join) of last leaf was not the sync!\n");
                        err = -EINVAL;
                        goto out;
                }

                if (sync->height != order) {
                        pr_err("Join does not have the expected height, found %d, expected %d\n",
                               sync->height, order);
                        err = -EINVAL;
                        goto out;
                }

                if (sync->bitmap != BIT(KSYNCMAP) - 1) {
                        pr_err("Join is not full!, found %x (%d) expected %lx (%d)\n",
                               sync->bitmap, hweight32(sync->bitmap),
                               BIT(KSYNCMAP) - 1, KSYNCMAP);
                        err = -EINVAL;
                        goto out;
                }

                /* Each of our children should be a leaf */
                for (idx = 0; idx < KSYNCMAP; idx++) {
                        struct i915_syncmap *leaf = __sync_child(sync)[idx];

                        if (leaf->height) {
                                pr_err("Child %d is a not leaf!\n", idx);
                                err = -EINVAL;
                                goto out;
                        }

                        if (leaf->parent != sync) {
                                pr_err("Child %d is not attached to us!\n",
                                       idx);
                                err = -EINVAL;
                                goto out;
                        }

                        if (!is_power_of_2(leaf->bitmap)) {
                                pr_err("Child %d holds more than one id, found %x (%d)\n",
                                       idx, leaf->bitmap, hweight32(leaf->bitmap));
                                err = -EINVAL;
                                goto out;
                        }

                        if (leaf->bitmap != BIT(idx)) {
                                pr_err("Child %d has wrong seqno idx, found %d, expected %d\n",
                                       idx, ilog2(leaf->bitmap), idx);
                                err = -EINVAL;
                                goto out;
                        }
                }
        }
out:
        return dump_syncmap(sync, err);
}

static int igt_syncmap_random(void *arg)
{
        I915_RND_STATE(prng);
        IGT_TIMEOUT(end_time);
        struct i915_syncmap *sync;
        unsigned long count, phase, i;
        u32 seqno;
        int err;

        i915_syncmap_init(&sync);

        /*
         * Having tried to test the individual operations within i915_syncmap,
         * run a smoketest exploring the entire u64 space with random
         * insertions.
         */

        count = 0;
        phase = jiffies + HZ/100 + 1;
        do {
                u64 context = i915_prandom_u64_state(&prng);

                err = i915_syncmap_set(&sync, context, 0);
                if (err)
                        goto out;

                count++;
        } while (!time_after(jiffies, phase));
        seqno = 0;

        phase = 0;
        do {
                I915_RND_STATE(ctx);
                u32 last_seqno = seqno;
                bool expect;

                seqno = prandom_u32_state(&prng);
                expect = seqno_later(last_seqno, seqno);

                for (i = 0; i < count; i++) {
                        u64 context = i915_prandom_u64_state(&ctx);

                        if (i915_syncmap_is_later(&sync, context, seqno) != expect) {
                                pr_err("context=%llu, last=%u this=%u did not match expectation (%d)\n",
                                       context, last_seqno, seqno, expect);
                                err = -EINVAL;
                                goto out;
                        }

                        err = i915_syncmap_set(&sync, context, seqno);
                        if (err)
                                goto out;
                }

                phase++;
        } while (!__igt_timeout(end_time, NULL));
        pr_debug("Completed %lu passes, each of %lu contexts\n", phase, count);
out:
        return dump_syncmap(sync, err);
}

int i915_syncmap_mock_selftests(void)
{
        static const struct i915_subtest tests[] = {
                SUBTEST(igt_syncmap_init),
                SUBTEST(igt_syncmap_one),
                SUBTEST(igt_syncmap_join_above),
                SUBTEST(igt_syncmap_join_below),
                SUBTEST(igt_syncmap_neighbours),
                SUBTEST(igt_syncmap_compact),
                SUBTEST(igt_syncmap_random),
        };

        return i915_subtests(tests, NULL);
}