// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
 */

#include "drm/drm_file.h"
#include "drm/msm_drm.h"

#include "linux/anon_inodes.h"
#include "linux/gfp_types.h"
#include "linux/poll.h"
#include "linux/slab.h"

#include "msm_drv.h"
#include "msm_gpu.h"
#include "msm_perfcntr.h"

#include "adreno/adreno_gpu.h"

/* space used: */
#define fifo_count(stream) \
        (CIRC_CNT((stream)->fifo.head, (stream)->fifo.tail, (stream)->fifo_size))
#define fifo_count_to_end(stream) \
        (CIRC_CNT_TO_END(smp_load_acquire(&(stream)->fifo.head), (stream)->fifo.tail, (stream)->fifo_size))
/* space available: */
#define fifo_space(stream) \
        (CIRC_SPACE((stream)->fifo.head, (stream)->fifo.tail, (stream)->fifo_size))

static int
msm_perfcntr_resume_locked(struct msm_perfcntr_stream *stream)
{
        if (!stream)
                return 0;

        /* Reprogram SEL regs on highest priority rb: */
        struct msm_ringbuffer *ring = stream->gpu->rb[0];

        queue_work(ring->sched.submit_wq, &stream->sel_work);

        hrtimer_start(&stream->sample_timer,
                      ns_to_ktime(stream->sample_period_ns),
                      HRTIMER_MODE_REL_PINNED);

        return 0;
}

int
msm_perfcntr_resume(struct msm_gpu *gpu)
{
        if (!gpu->perfcntrs)
                return 0;
        guard(mutex)(&gpu->perfcntr_lock);
        return msm_perfcntr_resume_locked(gpu->perfcntrs->stream);
}

static void
msm_perfcntr_suspend_locked(struct msm_perfcntr_stream *stream)
{
        if (!stream)
                return;

        hrtimer_cancel(&stream->sample_timer);
        kthread_cancel_work_sync(&stream->sample_work);

        /*
         * We can't use cancel_work_sync() here, since sel_work acquires
         * gpu->lock which (a) in suspend path can already be held, or
         * (b) in release path would invert the order of gpu->lock and
         * gpu->perfcntr_lock.  Either would cause deadlock.
         */
        cancel_work(&stream->sel_work);

        stream->sel_fence = ++stream->gpu->perfcntrs->sel_seqno;
        stream->seqno = 0;
}

void
msm_perfcntr_suspend(struct msm_gpu *gpu)
{
        if (!gpu->perfcntrs)
                return;
        guard(mutex)(&gpu->perfcntr_lock);
        msm_perfcntr_suspend_locked(gpu->perfcntrs->stream);
}

static int
msm_perfcntrs_stream_release(struct inode *inode, struct file *file)
{
        struct msm_perfcntr_stream *stream = file->private_data;
        struct msm_gpu *gpu = stream->gpu;

        scoped_guard (mutex, &gpu->perfcntr_lock) {
                struct msm_perfcntr_state *perfcntrs = gpu->perfcntrs;

                msm_perfcntr_suspend_locked(stream);
                perfcntrs->stream = NULL;

                /* release previously allocated counters: */
                for (unsigned i = 0; i < gpu->num_perfcntr_groups; i++)
                        perfcntrs->groups[i]->allocated_counters = 0;
        }

        /*
         * In the suspend path we use async cancel_work(), to avoid blocking
         * on sel_work, which acquires gpu->lock (which could deadlock since
         * other paths acquire gpu->lock before perfcntr_lock) or already
         * hold gpu->lock.
         *
         * But since we are freeing the stream, after dropping perfcntr_lock
         * we need to block until sel_work is done:
         */
        cancel_work_sync(&stream->sel_work);

        kfree(stream->group_idx);
        kfree(stream->fifo.buf);
        kfree(stream);

        return 0;
}

static __poll_t
msm_perfcntrs_stream_poll(struct file *file, poll_table *wait)
{
        struct msm_perfcntr_stream *stream = file->private_data;
        __poll_t events = 0;

        poll_wait(file, &stream->poll_wq, wait);

        /* Are there samples to read? */
        if (fifo_count(stream) > 0)
                events |= EPOLLIN;

        return events;
}

static ssize_t
msm_perfcntrs_stream_read(struct file *file, char __user *buf,
                          size_t count, loff_t *ppos)
{
        struct msm_perfcntr_stream *stream = file->private_data;
        int ret;

        if (!(file->f_flags & O_NONBLOCK)) {
                ret = wait_event_interruptible(stream->poll_wq,
                                               fifo_count(stream) > 0);
                if (ret)
                        return ret;
        }

        guard(mutex)(&stream->read_lock);

        struct circ_buf *fifo = &stream->fifo;
        const char *fptr = &fifo->buf[fifo->tail];

        count = min_t(size_t, count, fifo_count_to_end(stream));
        if (!count)
                return -EAGAIN;
        if (copy_to_user(buf, fptr, count))
                return -EFAULT;

        smp_store_release(&fifo->tail, (fifo->tail + count) & (stream->fifo_size - 1));
        *ppos += count;

        return count;
}

static const struct file_operations stream_fops = {
        .owner          = THIS_MODULE,
        .release        = msm_perfcntrs_stream_release,
        .poll           = msm_perfcntrs_stream_poll,
        .read           = msm_perfcntrs_stream_read,
};

static void
sel_worker(struct work_struct *w)
{
        struct msm_perfcntr_stream *stream =
                container_of(w, typeof(*stream), sel_work);
        struct msm_gpu *gpu = stream->gpu;
        /* Reprogram SEL regs on highest priority rb: */
        struct msm_ringbuffer *ring = stream->gpu->rb[0];

        /*
         * If in the process of resuming, wait for that.  Otherwise sel_worker
         * which is enqueued in the resume path can be scheduled before the
         * resume completes.
         */
        pm_runtime_barrier(&gpu->pdev->dev);

        /*
         * sel_work could end up scheduled before suspend, but running
         * after.  See msm_perfcntr_suspend_locked()
         *
         * So if we end up running sel_work after the GPU is already
         * suspended, just bail.  It will be scheduled again after
         * the GPU is resumed.
         */
        if (!pm_runtime_get_if_active(&gpu->pdev->dev))
                return;

        scoped_guard (mutex, &gpu->lock) {
                guard(mutex)(&gpu->perfcntr_lock);

                if (stream == gpu->perfcntrs->stream) {
                        msm_gpu_hw_init(gpu);
                        gpu->funcs->perfcntr_configure(gpu, ring, stream);
                }
        }

        pm_runtime_put_autosuspend(&gpu->pdev->dev);
}

static void
sample_write(struct msm_perfcntr_stream *stream, int *head, const void *buf, size_t sz)
{
        /*
         * FIFO size is power-of-two, and guaranteed to have enough space to
         * fit what we are writing.  So we should not hit the wrap-around
         * point writing things that are power-of-two sized
         */
        WARN_ON(CIRC_SPACE_TO_END(*head, stream->fifo.tail, stream->fifo_size) < sz);

        memcpy(&stream->fifo.buf[*head], buf, sz);

        /* Advance head, wrapping around if necessary: */
        *head = (*head + sz) & (stream->fifo_size - 1);
}

static void
sample_write_u32(struct msm_perfcntr_stream *stream, int *head, uint32_t val)
{
        sample_write(stream, head, &val, sizeof(val));
}

static void
sample_write_u64(struct msm_perfcntr_stream *stream, int *head, uint64_t val)
{
        sample_write(stream, head, &val, sizeof(val));
}

static void
sample_worker(struct kthread_work *work)
{
        struct msm_perfcntr_stream *stream =
                container_of(work, typeof(*stream), sample_work);
        struct msm_gpu *gpu = stream->gpu;
        struct msm_rbmemptrs *memptrs = gpu->rb[0]->memptrs;

        if (memptrs->perfcntr_fence != stream->sel_fence)
                return;

        /*
         * Ensure we have enough space to capture a sample period's
         * worth of data:
         */
        if (stream->period_size > fifo_space(stream)) {
                stream->seqno = 0;
                return;
        }

        /* Inhibit IFPC while accessing registers: */
        if (gpu->funcs->sysprof_setup)
                gpu->funcs->sysprof_setup(gpu, true);

        if (gpu->funcs->perfcntr_flush)
                gpu->funcs->perfcntr_flush(gpu);

        /* Keep local copy of head to avoid updating fifo until the end: */
        int head = stream->fifo.head;

        /*
         * We expect the GPU to be powered at this point, as the timer
         * and kthread work are canceled/flushed in the suspend path:
         */
        sample_write_u64(stream, &head,
                         to_adreno_gpu(gpu)->funcs->get_timestamp(gpu));
        sample_write_u32(stream, &head, stream->seqno++);
        sample_write_u32(stream, &head, 0);

        for (unsigned i = 0; i < stream->nr_groups; i++) {
                unsigned group_idx = msm_perfcntr_group_idx(stream, i);
                unsigned base = msm_perfcntr_counter_base(stream, group_idx);

                const struct msm_perfcntr_group *group =
                        &gpu->perfcntr_groups[group_idx];

                struct msm_perfcntr_group_state *group_state =
                        gpu->perfcntrs->groups[group_idx];

                unsigned nr = group_state->allocated_counters;
                for (unsigned j = 0; j < nr; j++) {
                        const struct msm_perfcntr_counter *counter =
                                &group->counters[j + base];
                        uint64_t val = gpu_read64(gpu, counter->counter_reg_lo);
                        sample_write_u64(stream, &head, val);
                }
        }

        /* Re-enable IFPC: */
        if (gpu->funcs->sysprof_setup)
                gpu->funcs->sysprof_setup(gpu, false);

        smp_store_release(&stream->fifo.head, head);
        wake_up_all(&stream->poll_wq);
}

static enum hrtimer_restart
sample_timer(struct hrtimer *hrtimer)
{
        struct msm_perfcntr_stream *stream =
                container_of(hrtimer, typeof(*stream), sample_timer);

        kthread_queue_work(stream->gpu->worker, &stream->sample_work);

        hrtimer_forward_now(hrtimer, ns_to_ktime(stream->sample_period_ns));

        return HRTIMER_RESTART;
}

static int
get_group_idx(struct msm_gpu *gpu, const char *name, size_t len)
{
        for (unsigned i = 0; i < gpu->num_perfcntr_groups; i++) {
                const struct msm_perfcntr_group *group =
                        &gpu->perfcntr_groups[i];
                if (!strncmp(group->name, name, len))
                        return i;
        }

        return -1;
}

static int
get_available_counters(struct msm_gpu *gpu, int group_idx, uint32_t flags)
{
        struct msm_perfcntr_state *perfcntrs = gpu->perfcntrs;

        /*
         * For local counter reservation, anything that is not used by
         * global perfcntr stream is available:
         */
        if (!(flags & MSM_PERFCNTR_STREAM)) {
                return gpu->perfcntr_groups[group_idx].num_counters -
                        perfcntrs->groups[group_idx]->allocated_counters;
        }

        /*
         * For global counter collection, anything that is not reserved by
         * one or more contexts is available:
         */
        guard(mutex)(&gpu->dev->filelist_mutex);

        unsigned reserved_counters = 0;
        struct drm_file *file;

        list_for_each_entry (file, &gpu->dev->filelist, lhead) {
                struct msm_context *ctx = file->driver_priv;

                if (!ctx || !ctx->perfctx)
                        continue;

                unsigned n = ctx->perfctx->reserved_counters[group_idx];
                reserved_counters = max(reserved_counters, n);
        }

        return gpu->perfcntr_groups[group_idx].num_counters - reserved_counters;
}

int
msm_ioctl_perfcntr_config(struct drm_device *dev, void *data, struct drm_file *file)
{
        struct msm_drm_private *priv = dev->dev_private;
        const struct drm_msm_perfcntr_config *args = data;
        struct msm_context *ctx = file->driver_priv;
        struct msm_gpu *gpu = priv->gpu;
        int stream_fd = 0;

        if (!gpu || !gpu->num_perfcntr_groups)
                return -ENXIO;

        struct msm_perfcntr_state *perfcntrs = gpu->perfcntrs;

        /*
         * Validate args that don't require locks/power first:
         */

        if (args->flags & ~MSM_PERFCNTR_FLAGS)
                return UERR(EINVAL, dev, "invalid flags");

        if (args->nr_groups && !args->group_stride)
                return UERR(EINVAL, dev, "invalid group_stride");

        if (args->nr_groups > gpu->num_perfcntr_groups)
                return UERR(EINVAL, dev, "too many groups");

        if (args->nr_groups && !args->groups)
                return UERR(EINVAL, dev, "no groups");

        if (args->flags & MSM_PERFCNTR_STREAM) {
                if (!perfmon_capable())
                        return UERR(EPERM, dev, "invalid permissions");
                if (!args->nr_groups)
                        return UERR(EINVAL, dev, "invalid nr_groups");
                if (!args->period)
                        return UERR(EINVAL, dev, "invalid sampling period");
                if (args->bufsz_shift > const_ilog2(SZ_128M))
                        return UERR(EINVAL, dev, "buffer size too big (>128M)");
        } else {
                if (args->period)
                        return UERR(EINVAL, dev, "sampling period not allowed");
                if (args->bufsz_shift)
                        return UERR(EINVAL, dev, "sample buf size not allowed");
        }

        /*
         * To avoid iterating over the groups multiple times, allocate and setup
         * both a ctx and global stream object.  Only one of the two will be
         * kept in the end.
         */

        struct msm_perfcntr_context_state *perfctx __free(kfree) = kzalloc(
                struct_size(perfctx, reserved_counters, gpu->num_perfcntr_groups),
                GFP_KERNEL);
        if (!perfctx)
                return -ENOMEM;

        struct msm_perfcntr_stream *stream __free(kfree) = kzalloc_obj(*stream);
        if (!stream)
                return -ENOMEM;

        uint8_t *nr_counters __free(kfree) = kzalloc_objs(uint8_t, gpu->num_perfcntr_groups);
        if (!nr_counters)
                return -ENOMEM;

        uint32_t *group_idx __free(kfree) = kzalloc_objs(uint32_t, args->nr_groups);
        if (!group_idx)
                return -ENOMEM;

        stream->gpu = gpu;
        stream->sample_period_ns = args->period;
        stream->nr_groups = args->nr_groups;
        stream->fifo_size = 1ull << args->bufsz_shift;

        mutex_init(&stream->read_lock);

        guard(mutex)(&gpu->perfcntr_lock);

        if (args->flags & MSM_PERFCNTR_STREAM) {
                if (perfcntrs->stream)
                        return UERR(EBUSY, dev, "perfcntr stream already open");
        }

        size_t bufsz = 16;  /* header size includes seqno and 64b timestamp: */
        int ret = 0;

        for (unsigned i = 0; i < args->nr_groups; i++) {
                struct drm_msm_perfcntr_group g = {0};
                size_t sz = min_t(size_t, args->group_stride, sizeof(g));
                void __user *userptr =
                        u64_to_user_ptr(args->groups + (i * args->group_stride));

                if (copy_from_user(&g, userptr, sz))
                        return -EFAULT;

                if (g.pad)
                        return UERR(EINVAL, dev, "groups[%d]: invalid pad", i);

                int idx = get_group_idx(gpu, g.group_name, sizeof(g.group_name));

                if (idx < 0)
                        return UERR(EINVAL, dev, "groups[%d]: unknown group", i);

                if (nr_counters[idx])
                        return UERR(EINVAL, dev, "groups[%d]: duplicate group", i);

                if (g.nr_countables > gpu->perfcntr_groups[idx].num_counters)
                        return UERR(EINVAL, dev, "groups[%d]: too many counters", i);

                if (args->flags & MSM_PERFCNTR_STREAM) {
                        if (g.nr_countables && !g.countables)
                                return UERR(EINVAL, dev, "groups[%d]: no countables", i);
                } else {
                        if (g.countables)
                                return UERR(EINVAL, dev, "groups[%d]: countables should be NULL", i);
                }

                int avail_counters = get_available_counters(gpu, idx, args->flags);
                if (g.nr_countables > avail_counters) {
                        /*
                         * Defer error return until we process all groups, in
                         * case there are other E2BIG groups:
                         */
                        ret = UERR(E2BIG, dev, "groups[%d]: too few counters available", i);

                        if (args->flags & MSM_PERFCNTR_UPDATE) {
                                /* Let userspace know how many counters are actually avail: */
                                g.nr_countables = avail_counters;
                                if (copy_to_user(userptr, &g, sz))
                                        return -EFAULT;
                        }
                }

                group_idx[i] = idx;
                perfctx->reserved_counters[idx] = g.nr_countables;

                /* +1 to catch duplicate zero sized groups: */
                nr_counters[idx] = g.nr_countables + 1;

                if (args->flags & MSM_PERFCNTR_STREAM) {
                        size_t sz = sizeof(uint32_t) * g.nr_countables;
                        void __user *userptr = u64_to_user_ptr(g.countables);

                        if (copy_from_user(perfcntrs->groups[idx]->countables, userptr, sz))
                                return -EFAULT;

                        /* Samples are 64b per countable: */
                        bufsz += 2 * sz;
                }
        }

        if (ret)
                return ret;

        if (args->flags & MSM_PERFCNTR_STREAM) {
                /*
                 * Validate requested buffer size is large enough for at least
                 * a single sample period.
                 *
                 * Note the circ_buf implementation needs to be 1 byte larger
                 * than max it can hold (see CIRC_SPACE()).
                 */
                if (stream->fifo_size <= bufsz)
                        return UERR(EINVAL, dev, "required buffer size: %zu", bufsz);

                /* There aren't enough counters to hit this limit: */
                WARN_ON(bufsz > SZ_128M);

                stream->period_size = bufsz;

                void *buf __free(kfree) = kmalloc(stream->fifo_size, GFP_KERNEL);
                if (!buf)
                        return -ENOMEM;

                FD_PREPARE(fdf, O_CLOEXEC,
                           anon_inode_getfile("[msm_perfcntrs]", &stream_fops, stream, 0));
                if (fdf.err)
                        return fdf.err;

                INIT_WORK(&stream->sel_work, sel_worker);
                kthread_init_work(&stream->sample_work, sample_worker);
                init_waitqueue_head(&stream->poll_wq);
                hrtimer_setup(&stream->sample_timer, sample_timer,
                              CLOCK_MONOTONIC, HRTIMER_MODE_REL);

                stream->sel_fence = ++perfcntrs->sel_seqno;
                stream->group_idx = no_free_ptr(group_idx);
                stream->fifo.buf = no_free_ptr(buf);

                /* commit the allocated counters, subtracting off original +1: */
                for (unsigned i = 0; i < gpu->num_perfcntr_groups; i++)
                        perfcntrs->groups[i]->allocated_counters = nr_counters[i] - 1;

                perfcntrs->stream = no_free_ptr(stream);

                msm_perfcntr_resume_locked(perfcntrs->stream);

                stream_fd = fd_publish(fdf);
        } else {
                kfree(ctx->perfctx);
                ctx->perfctx = no_free_ptr(perfctx);
        }

        return stream_fd;
}

/**
 * msm_perfcntr_group_idx - map idx of perfcntr group to group_idx
 * @stream: The global perfcntr stream
 * @n: The requested group_idx
 *
 * The PERFCNTR_CONFIG ioctl requested N counters/countables per perfcntr
 * group, but the order of groups is not required to match the order they
 * are defined in the perfcntr tables (which is not stable/UABI, only the
 * group names are UABI).
 *
 * But the order samples are returned in the stream should match the
 * order they are requested in the PERFCNTR_CONFIG ioctl.  This helper
 * handles the order remapping.
 *
 * Returns an index into gpu->perfcntr_groups[] and perfcntrs->groups[].
 */
uint32_t
msm_perfcntr_group_idx(const struct msm_perfcntr_stream *stream, uint32_t n)
{
        WARN_ON_ONCE(n >= stream->nr_groups);
        return stream->group_idx[n];
}

/**
 * msm_perfcntr_counter_base - get idx of the first counter in group
 * @stream: The global perfcntr stream
 * @group_idx: the index of the counter group
 *
 * For global counter collection, counters are allocated from the end
 * (last counter) while UMD allocates them from the start (0..N-1).
 * Since UMD always allocated them from the start this also minimizes
 * the chance of conflict when using old UMD which predates
 * PERFCNTR_CONFIG ioctl.
 *
 * Returns the index of first counter to use.  An index into
 * msm_perfcntr_group::counters[].
 */
uint32_t
msm_perfcntr_counter_base(const struct msm_perfcntr_stream *stream, uint32_t group_idx)
{
        struct msm_gpu *gpu = stream->gpu;
        struct msm_perfcntr_state *perfcntrs = gpu->perfcntrs;
        unsigned num_counters = gpu->perfcntr_groups[group_idx].num_counters;
        unsigned allocated_counters = perfcntrs->groups[group_idx]->allocated_counters;

        return num_counters - allocated_counters;
}

static void
__msm_perfcntr_cleanup(struct msm_gpu *gpu, struct msm_perfcntr_state *perfcntrs)
{
        struct device *dev = &gpu->pdev->dev;

        for (unsigned i = 0; i < gpu->num_perfcntr_groups; i++)
                devm_kfree(dev, perfcntrs->groups[i]);

        devm_kfree(dev, perfcntrs);
}

void
msm_perfcntr_cleanup(struct msm_gpu *gpu)
{
        if (!gpu->perfcntrs)
                return;

        __msm_perfcntr_cleanup(gpu, gpu->perfcntrs);
        gpu->perfcntrs = NULL;
}

struct msm_perfcntr_state *
msm_perfcntr_init(struct msm_gpu *gpu)
{
        struct msm_perfcntr_state *perfcntrs;
        struct device *dev = &gpu->pdev->dev;
        size_t sz;

        sz = struct_size(perfcntrs, groups, gpu->num_perfcntr_groups);
        perfcntrs = devm_kzalloc(dev, sz, GFP_KERNEL);
        if (!perfcntrs)
                return ERR_PTR(-ENOMEM);

        for (unsigned i = 0; i < gpu->num_perfcntr_groups; i++) {
                const struct msm_perfcntr_group *group =
                        &gpu->perfcntr_groups[i];

                sz = struct_size(perfcntrs->groups[i], countables, group->num_counters);
                perfcntrs->groups[i] = devm_kzalloc(dev, sz, GFP_KERNEL);
                if (!perfcntrs->groups[i]) {
                        __msm_perfcntr_cleanup(gpu, perfcntrs);
                        return ERR_PTR(-ENOMEM);
                }
        }

        return perfcntrs;
}