// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2013 Red Hat
 * Author: Rob Clark <robdclark@gmail.com>
 */

#include "msm_gpu.h"
#include "msm_gem.h"
#include "msm_mmu.h"
#include "msm_fence.h"
#include "msm_gpu_trace.h"
#include "adreno/adreno_gpu.h"

#include <generated/utsrelease.h>
#include <linux/string_helpers.h>
#include <linux/devfreq.h>
#include <linux/devfreq_cooling.h>
#include <linux/devcoredump.h>
#include <linux/sched/task.h>

/*
 * Power Management:
 */

static int msm_devfreq_target(struct device *dev, unsigned long *freq,
                u32 flags)
{
        struct msm_gpu *gpu = dev_to_gpu(dev);
        struct dev_pm_opp *opp;

        opp = devfreq_recommended_opp(dev, freq, flags);

        if (IS_ERR(opp))
                return PTR_ERR(opp);

        trace_msm_gpu_freq_change(dev_pm_opp_get_freq(opp));

        if (gpu->funcs->gpu_set_freq)
                gpu->funcs->gpu_set_freq(gpu, opp);
        else
                clk_set_rate(gpu->core_clk, *freq);

        dev_pm_opp_put(opp);

        return 0;
}

static int msm_devfreq_get_dev_status(struct device *dev,
                struct devfreq_dev_status *status)
{
        struct msm_gpu *gpu = dev_to_gpu(dev);
        ktime_t time;

        if (gpu->funcs->gpu_get_freq)
                status->current_frequency = gpu->funcs->gpu_get_freq(gpu);
        else
                status->current_frequency = clk_get_rate(gpu->core_clk);

        status->busy_time = gpu->funcs->gpu_busy(gpu);

        time = ktime_get();
        status->total_time = ktime_us_delta(time, gpu->devfreq.time);
        gpu->devfreq.time = time;

        return 0;
}

static int msm_devfreq_get_cur_freq(struct device *dev, unsigned long *freq)
{
        struct msm_gpu *gpu = dev_to_gpu(dev);

        if (gpu->funcs->gpu_get_freq)
                *freq = gpu->funcs->gpu_get_freq(gpu);
        else
                *freq = clk_get_rate(gpu->core_clk);

        return 0;
}

static struct devfreq_dev_profile msm_devfreq_profile = {
        .polling_ms = 10,
        .target = msm_devfreq_target,
        .get_dev_status = msm_devfreq_get_dev_status,
        .get_cur_freq = msm_devfreq_get_cur_freq,
};

static void msm_devfreq_init(struct msm_gpu *gpu)
{
        /* We need target support to do devfreq */
        if (!gpu->funcs->gpu_busy)
                return;

        msm_devfreq_profile.initial_freq = gpu->fast_rate;

        /*
         * Don't set the freq_table or max_state and let devfreq build the table
         * from OPP
         * After a deferred probe, these may have be left to non-zero values,
         * so set them back to zero before creating the devfreq device
         */
        msm_devfreq_profile.freq_table = NULL;
        msm_devfreq_profile.max_state = 0;

        gpu->devfreq.devfreq = devm_devfreq_add_device(&gpu->pdev->dev,
                        &msm_devfreq_profile, DEVFREQ_GOV_SIMPLE_ONDEMAND,
                        NULL);

        if (IS_ERR(gpu->devfreq.devfreq)) {
                DRM_DEV_ERROR(&gpu->pdev->dev, "Couldn't initialize GPU devfreq\n");
                gpu->devfreq.devfreq = NULL;
                return;
        }

        devfreq_suspend_device(gpu->devfreq.devfreq);

        gpu->cooling = of_devfreq_cooling_register(gpu->pdev->dev.of_node,
                        gpu->devfreq.devfreq);
        if (IS_ERR(gpu->cooling)) {
                DRM_DEV_ERROR(&gpu->pdev->dev,
                                "Couldn't register GPU cooling device\n");
                gpu->cooling = NULL;
        }
}

static int enable_pwrrail(struct msm_gpu *gpu)
{
        struct drm_device *dev = gpu->dev;
        int ret = 0;

        if (gpu->gpu_reg) {
                ret = regulator_enable(gpu->gpu_reg);
                if (ret) {
                        DRM_DEV_ERROR(dev->dev, "failed to enable 'gpu_reg': %d\n", ret);
                        return ret;
                }
        }

        if (gpu->gpu_cx) {
                ret = regulator_enable(gpu->gpu_cx);
                if (ret) {
                        DRM_DEV_ERROR(dev->dev, "failed to enable 'gpu_cx': %d\n", ret);
                        return ret;
                }
        }

        return 0;
}

static int disable_pwrrail(struct msm_gpu *gpu)
{
        if (gpu->gpu_cx)
                regulator_disable(gpu->gpu_cx);
        if (gpu->gpu_reg)
                regulator_disable(gpu->gpu_reg);
        return 0;
}

static int enable_clk(struct msm_gpu *gpu)
{
        if (gpu->core_clk && gpu->fast_rate)
                clk_set_rate(gpu->core_clk, gpu->fast_rate);

        /* Set the RBBM timer rate to 19.2Mhz */
        if (gpu->rbbmtimer_clk)
                clk_set_rate(gpu->rbbmtimer_clk, 19200000);

        return clk_bulk_prepare_enable(gpu->nr_clocks, gpu->grp_clks);
}

static int disable_clk(struct msm_gpu *gpu)
{
        clk_bulk_disable_unprepare(gpu->nr_clocks, gpu->grp_clks);

        /*
         * Set the clock to a deliberately low rate. On older targets the clock
         * speed had to be non zero to avoid problems. On newer targets this
         * will be rounded down to zero anyway so it all works out.
         */
        if (gpu->core_clk)
                clk_set_rate(gpu->core_clk, 27000000);

        if (gpu->rbbmtimer_clk)
                clk_set_rate(gpu->rbbmtimer_clk, 0);

        return 0;
}

static int enable_axi(struct msm_gpu *gpu)
{
        return clk_prepare_enable(gpu->ebi1_clk);
}

static int disable_axi(struct msm_gpu *gpu)
{
        clk_disable_unprepare(gpu->ebi1_clk);
        return 0;
}

void msm_gpu_resume_devfreq(struct msm_gpu *gpu)
{
        gpu->devfreq.busy_cycles = 0;
        gpu->devfreq.time = ktime_get();

        devfreq_resume_device(gpu->devfreq.devfreq);
}

int msm_gpu_pm_resume(struct msm_gpu *gpu)
{
        int ret;

        DBG("%s", gpu->name);
        trace_msm_gpu_resume(0);

        ret = enable_pwrrail(gpu);
        if (ret)
                return ret;

        ret = enable_clk(gpu);
        if (ret)
                return ret;

        ret = enable_axi(gpu);
        if (ret)
                return ret;

        msm_gpu_resume_devfreq(gpu);

        gpu->needs_hw_init = true;

        return 0;
}

int msm_gpu_pm_suspend(struct msm_gpu *gpu)
{
        int ret;

        DBG("%s", gpu->name);
        trace_msm_gpu_suspend(0);

        devfreq_suspend_device(gpu->devfreq.devfreq);

        ret = disable_axi(gpu);
        if (ret)
                return ret;

        ret = disable_clk(gpu);
        if (ret)
                return ret;

        ret = disable_pwrrail(gpu);
        if (ret)
                return ret;

        gpu->suspend_count++;

        return 0;
}

int msm_gpu_hw_init(struct msm_gpu *gpu)
{
        int ret;

        WARN_ON(!mutex_is_locked(&gpu->dev->struct_mutex));

        if (!gpu->needs_hw_init)
                return 0;

        disable_irq(gpu->irq);
        ret = gpu->funcs->hw_init(gpu);
        if (!ret)
                gpu->needs_hw_init = false;
        enable_irq(gpu->irq);

        return ret;
}

static void update_fences(struct msm_gpu *gpu, struct msm_ringbuffer *ring,
                uint32_t fence)
{
        struct msm_gem_submit *submit;

        spin_lock(&ring->submit_lock);
        list_for_each_entry(submit, &ring->submits, node) {
                if (submit->seqno > fence)
                        break;

                msm_update_fence(submit->ring->fctx,
                        submit->fence->seqno);
        }
        spin_unlock(&ring->submit_lock);
}

#ifdef CONFIG_DEV_COREDUMP
static ssize_t msm_gpu_devcoredump_read(char *buffer, loff_t offset,
                size_t count, void *data, size_t datalen)
{
        struct msm_gpu *gpu = data;
        struct drm_print_iterator iter;
        struct drm_printer p;
        struct msm_gpu_state *state;

        state = msm_gpu_crashstate_get(gpu);
        if (!state)
                return 0;

        iter.data = buffer;
        iter.offset = 0;
        iter.start = offset;
        iter.remain = count;

        p = drm_coredump_printer(&iter);

        drm_printf(&p, "---\n");
        drm_printf(&p, "kernel: " UTS_RELEASE "\n");
        drm_printf(&p, "module: " KBUILD_MODNAME "\n");
        drm_printf(&p, "time: %lld.%09ld\n",
                state->time.tv_sec, state->time.tv_nsec);
        if (state->comm)
                drm_printf(&p, "comm: %s\n", state->comm);
        if (state->cmd)
                drm_printf(&p, "cmdline: %s\n", state->cmd);

        gpu->funcs->show(gpu, state, &p);

        msm_gpu_crashstate_put(gpu);

        return count - iter.remain;
}

static void msm_gpu_devcoredump_free(void *data)
{
        struct msm_gpu *gpu = data;

        msm_gpu_crashstate_put(gpu);
}

static void msm_gpu_crashstate_get_bo(struct msm_gpu_state *state,
                struct msm_gem_object *obj, u64 iova, u32 flags)
{
        struct msm_gpu_state_bo *state_bo = &state->bos[state->nr_bos];

        /* Don't record write only objects */
        state_bo->size = obj->base.size;
        state_bo->iova = iova;

        /* Only store data for non imported buffer objects marked for read */
        if ((flags & MSM_SUBMIT_BO_READ) && !obj->base.import_attach) {
                void *ptr;

                state_bo->data = kvmalloc(obj->base.size, GFP_KERNEL);
                if (!state_bo->data)
                        goto out;

                msm_gem_lock(&obj->base);
                ptr = msm_gem_get_vaddr_active(&obj->base);
                msm_gem_unlock(&obj->base);
                if (IS_ERR(ptr)) {
                        kvfree(state_bo->data);
                        state_bo->data = NULL;
                        goto out;
                }

                memcpy(state_bo->data, ptr, obj->base.size);
                msm_gem_put_vaddr(&obj->base);
        }
out:
        state->nr_bos++;
}

static void msm_gpu_crashstate_capture(struct msm_gpu *gpu,
                struct msm_gem_submit *submit, char *comm, char *cmd)
{
        struct msm_gpu_state *state;

        /* Check if the target supports capturing crash state */
        if (!gpu->funcs->gpu_state_get)
                return;

        /* Only save one crash state at a time */
        if (gpu->crashstate)
                return;

        state = gpu->funcs->gpu_state_get(gpu);
        if (IS_ERR_OR_NULL(state))
                return;

        /* Fill in the additional crash state information */
        state->comm = kstrdup(comm, GFP_KERNEL);
        state->cmd = kstrdup(cmd, GFP_KERNEL);
        state->fault_info = gpu->fault_info;

        if (submit) {
                int i, nr = 0;

                /* count # of buffers to dump: */
                for (i = 0; i < submit->nr_bos; i++)
                        if (should_dump(submit, i))
                                nr++;
                /* always dump cmd bo's, but don't double count them: */
                for (i = 0; i < submit->nr_cmds; i++)
                        if (!should_dump(submit, submit->cmd[i].idx))
                                nr++;

                state->bos = kcalloc(nr,
                        sizeof(struct msm_gpu_state_bo), GFP_KERNEL);

                for (i = 0; i < submit->nr_bos; i++) {
                        if (should_dump(submit, i)) {
                                msm_gpu_crashstate_get_bo(state, submit->bos[i].obj,
                                        submit->bos[i].iova, submit->bos[i].flags);
                        }
                }

                for (i = 0; state->bos && i < submit->nr_cmds; i++) {
                        int idx = submit->cmd[i].idx;

                        if (!should_dump(submit, submit->cmd[i].idx)) {
                                msm_gpu_crashstate_get_bo(state, submit->bos[idx].obj,
                                        submit->bos[idx].iova, submit->bos[idx].flags);
                        }
                }
        }

        /* Set the active crash state to be dumped on failure */
        gpu->crashstate = state;

        /* FIXME: Release the crashstate if this errors out? */
        dev_coredumpm(gpu->dev->dev, THIS_MODULE, gpu, 0, GFP_KERNEL,
                msm_gpu_devcoredump_read, msm_gpu_devcoredump_free);
}
#else
static void msm_gpu_crashstate_capture(struct msm_gpu *gpu,
                struct msm_gem_submit *submit, char *comm, char *cmd)
{
}
#endif

/*
 * Hangcheck detection for locked gpu:
 */

static struct msm_gem_submit *
find_submit(struct msm_ringbuffer *ring, uint32_t fence)
{
        struct msm_gem_submit *submit;

        spin_lock(&ring->submit_lock);
        list_for_each_entry(submit, &ring->submits, node) {
                if (submit->seqno == fence) {
                        spin_unlock(&ring->submit_lock);
                        return submit;
                }
        }
        spin_unlock(&ring->submit_lock);

        return NULL;
}

static void retire_submits(struct msm_gpu *gpu);

static void recover_worker(struct kthread_work *work)
{
        struct msm_gpu *gpu = container_of(work, struct msm_gpu, recover_work);
        struct drm_device *dev = gpu->dev;
        struct msm_drm_private *priv = dev->dev_private;
        struct msm_gem_submit *submit;
        struct msm_ringbuffer *cur_ring = gpu->funcs->active_ring(gpu);
        char *comm = NULL, *cmd = NULL;
        int i;

        mutex_lock(&dev->struct_mutex);

        DRM_DEV_ERROR(dev->dev, "%s: hangcheck recover!\n", gpu->name);

        submit = find_submit(cur_ring, cur_ring->memptrs->fence + 1);
        if (submit) {
                struct task_struct *task;

                /* Increment the fault counts */
                gpu->global_faults++;
                submit->queue->faults++;

                task = get_pid_task(submit->pid, PIDTYPE_PID);
                if (task) {
                        comm = kstrdup(task->comm, GFP_KERNEL);
                        cmd = kstrdup_quotable_cmdline(task, GFP_KERNEL);
                        put_task_struct(task);
                }

                /* msm_rd_dump_submit() needs bo locked to dump: */
                for (i = 0; i < submit->nr_bos; i++)
                        msm_gem_lock(&submit->bos[i].obj->base);

                if (comm && cmd) {
                        DRM_DEV_ERROR(dev->dev, "%s: offending task: %s (%s)\n",
                                gpu->name, comm, cmd);

                        msm_rd_dump_submit(priv->hangrd, submit,
                                "offending task: %s (%s)", comm, cmd);
                } else {
                        msm_rd_dump_submit(priv->hangrd, submit, NULL);
                }

                for (i = 0; i < submit->nr_bos; i++)
                        msm_gem_unlock(&submit->bos[i].obj->base);
        }

        /* Record the crash state */
        pm_runtime_get_sync(&gpu->pdev->dev);
        msm_gpu_crashstate_capture(gpu, submit, comm, cmd);
        pm_runtime_put_sync(&gpu->pdev->dev);

        kfree(cmd);
        kfree(comm);

        /*
         * Update all the rings with the latest and greatest fence.. this
         * needs to happen after msm_rd_dump_submit() to ensure that the
         * bo's referenced by the offending submit are still around.
         */
        for (i = 0; i < gpu->nr_rings; i++) {
                struct msm_ringbuffer *ring = gpu->rb[i];

                uint32_t fence = ring->memptrs->fence;

                /*
                 * For the current (faulting?) ring/submit advance the fence by
                 * one more to clear the faulting submit
                 */
                if (ring == cur_ring)
                        fence++;

                update_fences(gpu, ring, fence);
        }

        if (msm_gpu_active(gpu)) {
                /* retire completed submits, plus the one that hung: */
                retire_submits(gpu);

                pm_runtime_get_sync(&gpu->pdev->dev);
                gpu->funcs->recover(gpu);
                pm_runtime_put_sync(&gpu->pdev->dev);

                /*
                 * Replay all remaining submits starting with highest priority
                 * ring
                 */
                for (i = 0; i < gpu->nr_rings; i++) {
                        struct msm_ringbuffer *ring = gpu->rb[i];

                        spin_lock(&ring->submit_lock);
                        list_for_each_entry(submit, &ring->submits, node)
                                gpu->funcs->submit(gpu, submit);
                        spin_unlock(&ring->submit_lock);
                }
        }

        mutex_unlock(&dev->struct_mutex);

        msm_gpu_retire(gpu);
}

static void fault_worker(struct kthread_work *work)
{
        struct msm_gpu *gpu = container_of(work, struct msm_gpu, fault_work);
        struct drm_device *dev = gpu->dev;
        struct msm_gem_submit *submit;
        struct msm_ringbuffer *cur_ring = gpu->funcs->active_ring(gpu);
        char *comm = NULL, *cmd = NULL;

        mutex_lock(&dev->struct_mutex);

        submit = find_submit(cur_ring, cur_ring->memptrs->fence + 1);
        if (submit && submit->fault_dumped)
                goto resume_smmu;

        if (submit) {
                struct task_struct *task;

                task = get_pid_task(submit->pid, PIDTYPE_PID);
                if (task) {
                        comm = kstrdup(task->comm, GFP_KERNEL);
                        cmd = kstrdup_quotable_cmdline(task, GFP_KERNEL);
                        put_task_struct(task);
                }

                /*
                 * When we get GPU iova faults, we can get 1000s of them,
                 * but we really only want to log the first one.
                 */
                submit->fault_dumped = true;
        }

        /* Record the crash state */
        pm_runtime_get_sync(&gpu->pdev->dev);
        msm_gpu_crashstate_capture(gpu, submit, comm, cmd);
        pm_runtime_put_sync(&gpu->pdev->dev);

        kfree(cmd);
        kfree(comm);

resume_smmu:
        memset(&gpu->fault_info, 0, sizeof(gpu->fault_info));
        gpu->aspace->mmu->funcs->resume_translation(gpu->aspace->mmu);

        mutex_unlock(&dev->struct_mutex);
}

static void hangcheck_timer_reset(struct msm_gpu *gpu)
{
        struct msm_drm_private *priv = gpu->dev->dev_private;
        mod_timer(&gpu->hangcheck_timer,
                        round_jiffies_up(jiffies + msecs_to_jiffies(priv->hangcheck_period)));
}

static void hangcheck_handler(struct timer_list *t)
{
        struct msm_gpu *gpu = from_timer(gpu, t, hangcheck_timer);
        struct drm_device *dev = gpu->dev;
        struct msm_ringbuffer *ring = gpu->funcs->active_ring(gpu);
        uint32_t fence = ring->memptrs->fence;

        if (fence != ring->hangcheck_fence) {
                /* some progress has been made.. ya! */
                ring->hangcheck_fence = fence;
        } else if (fence < ring->seqno) {
                /* no progress and not done.. hung! */
                ring->hangcheck_fence = fence;
                DRM_DEV_ERROR(dev->dev, "%s: hangcheck detected gpu lockup rb %d!\n",
                                gpu->name, ring->id);
                DRM_DEV_ERROR(dev->dev, "%s:     completed fence: %u\n",
                                gpu->name, fence);
                DRM_DEV_ERROR(dev->dev, "%s:     submitted fence: %u\n",
                                gpu->name, ring->seqno);

                kthread_queue_work(gpu->worker, &gpu->recover_work);
        }

        /* if still more pending work, reset the hangcheck timer: */
        if (ring->seqno > ring->hangcheck_fence)
                hangcheck_timer_reset(gpu);

        /* workaround for missing irq: */
        kthread_queue_work(gpu->worker, &gpu->retire_work);
}

/*
 * Performance Counters:
 */

/* called under perf_lock */
static int update_hw_cntrs(struct msm_gpu *gpu, uint32_t ncntrs, uint32_t *cntrs)
{
        uint32_t current_cntrs[ARRAY_SIZE(gpu->last_cntrs)];
        int i, n = min(ncntrs, gpu->num_perfcntrs);

        /* read current values: */
        for (i = 0; i < gpu->num_perfcntrs; i++)
                current_cntrs[i] = gpu_read(gpu, gpu->perfcntrs[i].sample_reg);

        /* update cntrs: */
        for (i = 0; i < n; i++)
                cntrs[i] = current_cntrs[i] - gpu->last_cntrs[i];

        /* save current values: */
        for (i = 0; i < gpu->num_perfcntrs; i++)
                gpu->last_cntrs[i] = current_cntrs[i];

        return n;
}

static void update_sw_cntrs(struct msm_gpu *gpu)
{
        ktime_t time;
        uint32_t elapsed;
        unsigned long flags;

        spin_lock_irqsave(&gpu->perf_lock, flags);
        if (!gpu->perfcntr_active)
                goto out;

        time = ktime_get();
        elapsed = ktime_to_us(ktime_sub(time, gpu->last_sample.time));

        gpu->totaltime += elapsed;
        if (gpu->last_sample.active)
                gpu->activetime += elapsed;

        gpu->last_sample.active = msm_gpu_active(gpu);
        gpu->last_sample.time = time;

out:
        spin_unlock_irqrestore(&gpu->perf_lock, flags);
}

void msm_gpu_perfcntr_start(struct msm_gpu *gpu)
{
        unsigned long flags;

        pm_runtime_get_sync(&gpu->pdev->dev);

        spin_lock_irqsave(&gpu->perf_lock, flags);
        /* we could dynamically enable/disable perfcntr registers too.. */
        gpu->last_sample.active = msm_gpu_active(gpu);
        gpu->last_sample.time = ktime_get();
        gpu->activetime = gpu->totaltime = 0;
        gpu->perfcntr_active = true;
        update_hw_cntrs(gpu, 0, NULL);
        spin_unlock_irqrestore(&gpu->perf_lock, flags);
}

void msm_gpu_perfcntr_stop(struct msm_gpu *gpu)
{
        gpu->perfcntr_active = false;
        pm_runtime_put_sync(&gpu->pdev->dev);
}

/* returns -errno or # of cntrs sampled */
int msm_gpu_perfcntr_sample(struct msm_gpu *gpu, uint32_t *activetime,
                uint32_t *totaltime, uint32_t ncntrs, uint32_t *cntrs)
{
        unsigned long flags;
        int ret;

        spin_lock_irqsave(&gpu->perf_lock, flags);

        if (!gpu->perfcntr_active) {
                ret = -EINVAL;
                goto out;
        }

        *activetime = gpu->activetime;
        *totaltime = gpu->totaltime;

        gpu->activetime = gpu->totaltime = 0;

        ret = update_hw_cntrs(gpu, ncntrs, cntrs);

out:
        spin_unlock_irqrestore(&gpu->perf_lock, flags);

        return ret;
}

/*
 * Cmdstream submission/retirement:
 */

static void retire_submit(struct msm_gpu *gpu, struct msm_ringbuffer *ring,
                struct msm_gem_submit *submit)
{
        int index = submit->seqno % MSM_GPU_SUBMIT_STATS_COUNT;
        volatile struct msm_gpu_submit_stats *stats;
        u64 elapsed, clock = 0;
        int i;

        stats = &ring->memptrs->stats[index];
        /* Convert 19.2Mhz alwayson ticks to nanoseconds for elapsed time */
        elapsed = (stats->alwayson_end - stats->alwayson_start) * 10000;
        do_div(elapsed, 192);

        /* Calculate the clock frequency from the number of CP cycles */
        if (elapsed) {
                clock = (stats->cpcycles_end - stats->cpcycles_start) * 1000;
                do_div(clock, elapsed);
        }

        trace_msm_gpu_submit_retired(submit, elapsed, clock,
                stats->alwayson_start, stats->alwayson_end);

        for (i = 0; i < submit->nr_bos; i++) {
                struct drm_gem_object *obj = &submit->bos[i].obj->base;

                msm_gem_lock(obj);
                msm_gem_active_put(obj);
                msm_gem_unpin_iova_locked(obj, submit->aspace);
                msm_gem_unlock(obj);
                drm_gem_object_put(obj);
        }

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

        spin_lock(&ring->submit_lock);
        list_del(&submit->node);
        spin_unlock(&ring->submit_lock);

        msm_gem_submit_put(submit);
}

static void retire_submits(struct msm_gpu *gpu)
{
        int i;

        /* Retire the commits starting with highest priority */
        for (i = 0; i < gpu->nr_rings; i++) {
                struct msm_ringbuffer *ring = gpu->rb[i];

                while (true) {
                        struct msm_gem_submit *submit = NULL;

                        spin_lock(&ring->submit_lock);
                        submit = list_first_entry_or_null(&ring->submits,
                                        struct msm_gem_submit, node);
                        spin_unlock(&ring->submit_lock);

                        /*
                         * If no submit, we are done.  If submit->fence hasn't
                         * been signalled, then later submits are not signalled
                         * either, so we are also done.
                         */
                        if (submit && dma_fence_is_signaled(submit->fence)) {
                                retire_submit(gpu, ring, submit);
                        } else {
                                break;
                        }
                }
        }
}

static void retire_worker(struct kthread_work *work)
{
        struct msm_gpu *gpu = container_of(work, struct msm_gpu, retire_work);
        int i;

        for (i = 0; i < gpu->nr_rings; i++)
                update_fences(gpu, gpu->rb[i], gpu->rb[i]->memptrs->fence);

        retire_submits(gpu);
}

/* call from irq handler to schedule work to retire bo's */
void msm_gpu_retire(struct msm_gpu *gpu)
{
        kthread_queue_work(gpu->worker, &gpu->retire_work);
        update_sw_cntrs(gpu);
}

/* add bo's to gpu's ring, and kick gpu: */
void msm_gpu_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
{
        struct drm_device *dev = gpu->dev;
        struct msm_drm_private *priv = dev->dev_private;
        struct msm_ringbuffer *ring = submit->ring;
        int i;

        WARN_ON(!mutex_is_locked(&dev->struct_mutex));

        pm_runtime_get_sync(&gpu->pdev->dev);

        msm_gpu_hw_init(gpu);

        submit->seqno = ++ring->seqno;

        msm_rd_dump_submit(priv->rd, submit, NULL);

        update_sw_cntrs(gpu);

        for (i = 0; i < submit->nr_bos; i++) {
                struct msm_gem_object *msm_obj = submit->bos[i].obj;
                struct drm_gem_object *drm_obj = &msm_obj->base;
                uint64_t iova;

                /* submit takes a reference to the bo and iova until retired: */
                drm_gem_object_get(&msm_obj->base);
                msm_gem_get_and_pin_iova_locked(&msm_obj->base, submit->aspace, &iova);

                if (submit->bos[i].flags & MSM_SUBMIT_BO_WRITE)
                        dma_resv_add_excl_fence(drm_obj->resv, submit->fence);
                else if (submit->bos[i].flags & MSM_SUBMIT_BO_READ)
                        dma_resv_add_shared_fence(drm_obj->resv, submit->fence);

                msm_gem_active_get(drm_obj, gpu);
        }

        /*
         * ring->submits holds a ref to the submit, to deal with the case
         * that a submit completes before msm_ioctl_gem_submit() returns.
         */
        msm_gem_submit_get(submit);

        spin_lock(&ring->submit_lock);
        list_add_tail(&submit->node, &ring->submits);
        spin_unlock(&ring->submit_lock);

        gpu->funcs->submit(gpu, submit);
        priv->lastctx = submit->queue->ctx;

        hangcheck_timer_reset(gpu);
}

/*
 * Init/Cleanup:
 */

static irqreturn_t irq_handler(int irq, void *data)
{
        struct msm_gpu *gpu = data;
        return gpu->funcs->irq(gpu);
}

static int get_clocks(struct platform_device *pdev, struct msm_gpu *gpu)
{
        int ret = devm_clk_bulk_get_all(&pdev->dev, &gpu->grp_clks);

        if (ret < 1) {
                gpu->nr_clocks = 0;
                return ret;
        }

        gpu->nr_clocks = ret;

        gpu->core_clk = msm_clk_bulk_get_clock(gpu->grp_clks,
                gpu->nr_clocks, "core");

        gpu->rbbmtimer_clk = msm_clk_bulk_get_clock(gpu->grp_clks,
                gpu->nr_clocks, "rbbmtimer");

        return 0;
}

/* Return a new address space for a msm_drm_private instance */
struct msm_gem_address_space *
msm_gpu_create_private_address_space(struct msm_gpu *gpu, struct task_struct *task)
{
        struct msm_gem_address_space *aspace = NULL;
        if (!gpu)
                return NULL;

        /*
         * If the target doesn't support private address spaces then return
         * the global one
         */
        if (gpu->funcs->create_private_address_space) {
                aspace = gpu->funcs->create_private_address_space(gpu);
                if (!IS_ERR(aspace))
                        aspace->pid = get_pid(task_pid(task));
        }

        if (IS_ERR_OR_NULL(aspace))
                aspace = msm_gem_address_space_get(gpu->aspace);

        return aspace;
}

int msm_gpu_init(struct drm_device *drm, struct platform_device *pdev,
                struct msm_gpu *gpu, const struct msm_gpu_funcs *funcs,
                const char *name, struct msm_gpu_config *config)
{
        int i, ret, nr_rings = config->nr_rings;
        void *memptrs;
        uint64_t memptrs_iova;

        if (WARN_ON(gpu->num_perfcntrs > ARRAY_SIZE(gpu->last_cntrs)))
                gpu->num_perfcntrs = ARRAY_SIZE(gpu->last_cntrs);

        gpu->dev = drm;
        gpu->funcs = funcs;
        gpu->name = name;

        gpu->worker = kthread_create_worker(0, "%s-worker", gpu->name);
        if (IS_ERR(gpu->worker)) {
                ret = PTR_ERR(gpu->worker);
                gpu->worker = NULL;
                goto fail;
        }

        sched_set_fifo_low(gpu->worker->task);

        INIT_LIST_HEAD(&gpu->active_list);
        kthread_init_work(&gpu->retire_work, retire_worker);
        kthread_init_work(&gpu->recover_work, recover_worker);
        kthread_init_work(&gpu->fault_work, fault_worker);

        timer_setup(&gpu->hangcheck_timer, hangcheck_handler, 0);

        spin_lock_init(&gpu->perf_lock);


        /* Map registers: */
        gpu->mmio = msm_ioremap(pdev, config->ioname, name);
        if (IS_ERR(gpu->mmio)) {
                ret = PTR_ERR(gpu->mmio);
                goto fail;
        }

        /* Get Interrupt: */
        gpu->irq = platform_get_irq(pdev, 0);
        if (gpu->irq < 0) {
                ret = gpu->irq;
                DRM_DEV_ERROR(drm->dev, "failed to get irq: %d\n", ret);
                goto fail;
        }

        ret = devm_request_irq(&pdev->dev, gpu->irq, irq_handler,
                        IRQF_TRIGGER_HIGH, gpu->name, gpu);
        if (ret) {
                DRM_DEV_ERROR(drm->dev, "failed to request IRQ%u: %d\n", gpu->irq, ret);
                goto fail;
        }

        ret = get_clocks(pdev, gpu);
        if (ret)
                goto fail;

        gpu->ebi1_clk = msm_clk_get(pdev, "bus");
        DBG("ebi1_clk: %p", gpu->ebi1_clk);
        if (IS_ERR(gpu->ebi1_clk))
                gpu->ebi1_clk = NULL;

        /* Acquire regulators: */
        gpu->gpu_reg = devm_regulator_get(&pdev->dev, "vdd");
        DBG("gpu_reg: %p", gpu->gpu_reg);
        if (IS_ERR(gpu->gpu_reg))
                gpu->gpu_reg = NULL;

        gpu->gpu_cx = devm_regulator_get(&pdev->dev, "vddcx");
        DBG("gpu_cx: %p", gpu->gpu_cx);
        if (IS_ERR(gpu->gpu_cx))
                gpu->gpu_cx = NULL;

        gpu->pdev = pdev;
        platform_set_drvdata(pdev, &gpu->adreno_smmu);

        msm_devfreq_init(gpu);


        gpu->aspace = gpu->funcs->create_address_space(gpu, pdev);

        if (gpu->aspace == NULL)
                DRM_DEV_INFO(drm->dev, "%s: no IOMMU, fallback to VRAM carveout!\n", name);
        else if (IS_ERR(gpu->aspace)) {
                ret = PTR_ERR(gpu->aspace);
                goto fail;
        }

        memptrs = msm_gem_kernel_new(drm,
                sizeof(struct msm_rbmemptrs) * nr_rings,
                check_apriv(gpu, MSM_BO_UNCACHED), gpu->aspace, &gpu->memptrs_bo,
                &memptrs_iova);

        if (IS_ERR(memptrs)) {
                ret = PTR_ERR(memptrs);
                DRM_DEV_ERROR(drm->dev, "could not allocate memptrs: %d\n", ret);
                goto fail;
        }

        msm_gem_object_set_name(gpu->memptrs_bo, "memptrs");

        if (nr_rings > ARRAY_SIZE(gpu->rb)) {
                DRM_DEV_INFO_ONCE(drm->dev, "Only creating %zu ringbuffers\n",
                        ARRAY_SIZE(gpu->rb));
                nr_rings = ARRAY_SIZE(gpu->rb);
        }

        /* Create ringbuffer(s): */
        for (i = 0; i < nr_rings; i++) {
                gpu->rb[i] = msm_ringbuffer_new(gpu, i, memptrs, memptrs_iova);

                if (IS_ERR(gpu->rb[i])) {
                        ret = PTR_ERR(gpu->rb[i]);
                        DRM_DEV_ERROR(drm->dev,
                                "could not create ringbuffer %d: %d\n", i, ret);
                        goto fail;
                }

                memptrs += sizeof(struct msm_rbmemptrs);
                memptrs_iova += sizeof(struct msm_rbmemptrs);
        }

        gpu->nr_rings = nr_rings;

        return 0;

fail:
        for (i = 0; i < ARRAY_SIZE(gpu->rb); i++)  {
                msm_ringbuffer_destroy(gpu->rb[i]);
                gpu->rb[i] = NULL;
        }

        msm_gem_kernel_put(gpu->memptrs_bo, gpu->aspace, false);

        platform_set_drvdata(pdev, NULL);
        return ret;
}

void msm_gpu_cleanup(struct msm_gpu *gpu)
{
        int i;

        DBG("%s", gpu->name);

        WARN_ON(!list_empty(&gpu->active_list));

        for (i = 0; i < ARRAY_SIZE(gpu->rb); i++) {
                msm_ringbuffer_destroy(gpu->rb[i]);
                gpu->rb[i] = NULL;
        }

        msm_gem_kernel_put(gpu->memptrs_bo, gpu->aspace, false);

        if (!IS_ERR_OR_NULL(gpu->aspace)) {
                gpu->aspace->mmu->funcs->detach(gpu->aspace->mmu);
                msm_gem_address_space_put(gpu->aspace);
        }

        if (gpu->worker) {
                kthread_destroy_worker(gpu->worker);
        }

        devfreq_cooling_unregister(gpu->cooling);
}