/*
 * Copyright (C) 2013 Red Hat
 * Author: Rob Clark <robdclark@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "msm_gpu.h"
#include "msm_gem.h"
#include "msm_mmu.h"
#include "msm_fence.h"


/*
 * Power Management:
 */

#ifdef DOWNSTREAM_CONFIG_MSM_BUS_SCALING
#include <mach/board.h>
static void bs_init(struct msm_gpu *gpu)
{
        if (gpu->bus_scale_table) {
                gpu->bsc = msm_bus_scale_register_client(gpu->bus_scale_table);
                DBG("bus scale client: %08x", gpu->bsc);
        }
}

static void bs_fini(struct msm_gpu *gpu)
{
        if (gpu->bsc) {
                msm_bus_scale_unregister_client(gpu->bsc);
                gpu->bsc = 0;
        }
}

static void bs_set(struct msm_gpu *gpu, int idx)
{
        if (gpu->bsc) {
                DBG("set bus scaling: %d", idx);
                msm_bus_scale_client_update_request(gpu->bsc, idx);
        }
}
#else
static void bs_init(struct msm_gpu *gpu) {}
static void bs_fini(struct msm_gpu *gpu) {}
static void bs_set(struct msm_gpu *gpu, int idx) {}
#endif

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) {
                        dev_err(dev->dev, "failed to enable 'gpu_reg': %d\n", ret);
                        return ret;
                }
        }

        if (gpu->gpu_cx) {
                ret = regulator_enable(gpu->gpu_cx);
                if (ret) {
                        dev_err(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)
{
        struct clk *rate_clk = NULL;
        int i;

        /* NOTE: kgsl_pwrctrl_clk() ignores grp_clks[0].. */
        for (i = ARRAY_SIZE(gpu->grp_clks) - 1; i > 0; i--) {
                if (gpu->grp_clks[i]) {
                        clk_prepare(gpu->grp_clks[i]);
                        rate_clk = gpu->grp_clks[i];
                }
        }

        if (rate_clk && gpu->fast_rate)
                clk_set_rate(rate_clk, gpu->fast_rate);

        for (i = ARRAY_SIZE(gpu->grp_clks) - 1; i > 0; i--)
                if (gpu->grp_clks[i])
                        clk_enable(gpu->grp_clks[i]);

        return 0;
}

static int disable_clk(struct msm_gpu *gpu)
{
        struct clk *rate_clk = NULL;
        int i;

        /* NOTE: kgsl_pwrctrl_clk() ignores grp_clks[0].. */
        for (i = ARRAY_SIZE(gpu->grp_clks) - 1; i > 0; i--) {
                if (gpu->grp_clks[i]) {
                        clk_disable(gpu->grp_clks[i]);
                        rate_clk = gpu->grp_clks[i];
                }
        }

        if (rate_clk && gpu->slow_rate)
                clk_set_rate(rate_clk, gpu->slow_rate);

        for (i = ARRAY_SIZE(gpu->grp_clks) - 1; i > 0; i--)
                if (gpu->grp_clks[i])
                        clk_unprepare(gpu->grp_clks[i]);

        return 0;
}

static int enable_axi(struct msm_gpu *gpu)
{
        if (gpu->ebi1_clk)
                clk_prepare_enable(gpu->ebi1_clk);
        if (gpu->bus_freq)
                bs_set(gpu, gpu->bus_freq);
        return 0;
}

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

int msm_gpu_pm_resume(struct msm_gpu *gpu)
{
        struct drm_device *dev = gpu->dev;
        int ret;

        DBG("%s: active_cnt=%d", gpu->name, gpu->active_cnt);

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

        if (gpu->active_cnt++ > 0)
                return 0;

        if (WARN_ON(gpu->active_cnt <= 0))
                return -EINVAL;

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

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

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

        return 0;
}

int msm_gpu_pm_suspend(struct msm_gpu *gpu)
{
        struct drm_device *dev = gpu->dev;
        int ret;

        DBG("%s: active_cnt=%d", gpu->name, gpu->active_cnt);

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

        if (--gpu->active_cnt > 0)
                return 0;

        if (WARN_ON(gpu->active_cnt < 0))
                return -EINVAL;

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

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

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

        return 0;
}

/*
 * Inactivity detection (for suspend):
 */

static void inactive_worker(struct work_struct *work)
{
        struct msm_gpu *gpu = container_of(work, struct msm_gpu, inactive_work);
        struct drm_device *dev = gpu->dev;

        if (gpu->inactive)
                return;

        DBG("%s: inactive!\n", gpu->name);
        mutex_lock(&dev->struct_mutex);
        if (!(msm_gpu_active(gpu) || gpu->inactive)) {
                disable_axi(gpu);
                disable_clk(gpu);
                gpu->inactive = true;
        }
        mutex_unlock(&dev->struct_mutex);
}

static void inactive_handler(unsigned long data)
{
        struct msm_gpu *gpu = (struct msm_gpu *)data;
        struct msm_drm_private *priv = gpu->dev->dev_private;

        queue_work(priv->wq, &gpu->inactive_work);
}

/* cancel inactive timer and make sure we are awake: */
static void inactive_cancel(struct msm_gpu *gpu)
{
        DBG("%s", gpu->name);
        del_timer(&gpu->inactive_timer);
        if (gpu->inactive) {
                enable_clk(gpu);
                enable_axi(gpu);
                gpu->inactive = false;
        }
}

static void inactive_start(struct msm_gpu *gpu)
{
        DBG("%s", gpu->name);
        mod_timer(&gpu->inactive_timer,
                        round_jiffies_up(jiffies + DRM_MSM_INACTIVE_JIFFIES));
}

/*
 * Hangcheck detection for locked gpu:
 */

static void retire_submits(struct msm_gpu *gpu);

static void recover_worker(struct work_struct *work)
{
        struct msm_gpu *gpu = container_of(work, struct msm_gpu, recover_work);
        struct drm_device *dev = gpu->dev;
        struct msm_gem_submit *submit;
        uint32_t fence = gpu->funcs->last_fence(gpu);

        msm_update_fence(gpu->fctx, fence + 1);

        mutex_lock(&dev->struct_mutex);

        dev_err(dev->dev, "%s: hangcheck recover!\n", gpu->name);
        list_for_each_entry(submit, &gpu->submit_list, node) {
                if (submit->fence->seqno == (fence + 1)) {
                        struct task_struct *task;

                        rcu_read_lock();
                        task = pid_task(submit->pid, PIDTYPE_PID);
                        if (task) {
                                dev_err(dev->dev, "%s: offending task: %s\n",
                                                gpu->name, task->comm);
                        }
                        rcu_read_unlock();
                        break;
                }
        }

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

                inactive_cancel(gpu);
                gpu->funcs->recover(gpu);

                /* replay the remaining submits after the one that hung: */
                list_for_each_entry(submit, &gpu->submit_list, node) {
                        gpu->funcs->submit(gpu, submit, NULL);
                }
        }

        mutex_unlock(&dev->struct_mutex);

        msm_gpu_retire(gpu);
}

static void hangcheck_timer_reset(struct msm_gpu *gpu)
{
        DBG("%s", gpu->name);
        mod_timer(&gpu->hangcheck_timer,
                        round_jiffies_up(jiffies + DRM_MSM_HANGCHECK_JIFFIES));
}

static void hangcheck_handler(unsigned long data)
{
        struct msm_gpu *gpu = (struct msm_gpu *)data;
        struct drm_device *dev = gpu->dev;
        struct msm_drm_private *priv = dev->dev_private;
        uint32_t fence = gpu->funcs->last_fence(gpu);

        if (fence != gpu->hangcheck_fence) {
                /* some progress has been made.. ya! */
                gpu->hangcheck_fence = fence;
        } else if (fence < gpu->fctx->last_fence) {
                /* no progress and not done.. hung! */
                gpu->hangcheck_fence = fence;
                dev_err(dev->dev, "%s: hangcheck detected gpu lockup!\n",
                                gpu->name);
                dev_err(dev->dev, "%s:     completed fence: %u\n",
                                gpu->name, fence);
                dev_err(dev->dev, "%s:     submitted fence: %u\n",
                                gpu->name, gpu->fctx->last_fence);
                queue_work(priv->wq, &gpu->recover_work);
        }

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

        /* workaround for missing irq: */
        queue_work(priv->wq, &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;

        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;
}

/* 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_gem_submit *submit)
{
        int i;

        for (i = 0; i < submit->nr_bos; i++) {
                struct msm_gem_object *msm_obj = submit->bos[i].obj;
                /* move to inactive: */
                msm_gem_move_to_inactive(&msm_obj->base);
                msm_gem_put_iova(&msm_obj->base, gpu->id);
                drm_gem_object_unreference(&msm_obj->base);
        }

        msm_gem_submit_free(submit);
}

static void retire_submits(struct msm_gpu *gpu)
{
        struct drm_device *dev = gpu->dev;

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

        while (!list_empty(&gpu->submit_list)) {
                struct msm_gem_submit *submit;

                submit = list_first_entry(&gpu->submit_list,
                                struct msm_gem_submit, node);

                if (fence_is_signaled(submit->fence)) {
                        retire_submit(gpu, submit);
                } else {
                        break;
                }
        }
}

static void retire_worker(struct work_struct *work)
{
        struct msm_gpu *gpu = container_of(work, struct msm_gpu, retire_work);
        struct drm_device *dev = gpu->dev;
        uint32_t fence = gpu->funcs->last_fence(gpu);

        msm_update_fence(gpu->fctx, fence);

        mutex_lock(&dev->struct_mutex);
        retire_submits(gpu);
        mutex_unlock(&dev->struct_mutex);

        if (!msm_gpu_active(gpu))
                inactive_start(gpu);
}

/* call from irq handler to schedule work to retire bo's */
void msm_gpu_retire(struct msm_gpu *gpu)
{
        struct msm_drm_private *priv = gpu->dev->dev_private;
        queue_work(priv->wq, &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 msm_file_private *ctx)
{
        struct drm_device *dev = gpu->dev;
        struct msm_drm_private *priv = dev->dev_private;
        int i;

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

        inactive_cancel(gpu);

        list_add_tail(&submit->node, &gpu->submit_list);

        msm_rd_dump_submit(submit);

        update_sw_cntrs(gpu);

        for (i = 0; i < submit->nr_bos; i++) {
                struct msm_gem_object *msm_obj = submit->bos[i].obj;
                uint32_t iova;

                /* can't happen yet.. but when we add 2d support we'll have
                 * to deal w/ cross-ring synchronization:
                 */
                WARN_ON(is_active(msm_obj) && (msm_obj->gpu != gpu));

                /* submit takes a reference to the bo and iova until retired: */
                drm_gem_object_reference(&msm_obj->base);
                msm_gem_get_iova_locked(&msm_obj->base,
                                submit->gpu->id, &iova);

                if (submit->bos[i].flags & MSM_SUBMIT_BO_WRITE)
                        msm_gem_move_to_active(&msm_obj->base, gpu, true, submit->fence);
                else if (submit->bos[i].flags & MSM_SUBMIT_BO_READ)
                        msm_gem_move_to_active(&msm_obj->base, gpu, false, submit->fence);
        }

        gpu->funcs->submit(gpu, submit, ctx);
        priv->lastctx = 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 const char *clk_names[] = {
                "src_clk", "core_clk", "iface_clk", "mem_clk", "mem_iface_clk",
                "alt_mem_iface_clk",
};

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, const char *ioname, const char *irqname, int ringsz)
{
        struct iommu_domain *iommu;
        int i, ret;

        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->inactive = true;
        gpu->fctx = msm_fence_context_alloc(drm, name);
        if (IS_ERR(gpu->fctx)) {
                ret = PTR_ERR(gpu->fctx);
                gpu->fctx = NULL;
                goto fail;
        }

        INIT_LIST_HEAD(&gpu->active_list);
        INIT_WORK(&gpu->retire_work, retire_worker);
        INIT_WORK(&gpu->inactive_work, inactive_worker);
        INIT_WORK(&gpu->recover_work, recover_worker);

        INIT_LIST_HEAD(&gpu->submit_list);

        setup_timer(&gpu->inactive_timer, inactive_handler,
                        (unsigned long)gpu);
        setup_timer(&gpu->hangcheck_timer, hangcheck_handler,
                        (unsigned long)gpu);

        spin_lock_init(&gpu->perf_lock);

        BUG_ON(ARRAY_SIZE(clk_names) != ARRAY_SIZE(gpu->grp_clks));

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

        /* Get Interrupt: */
        gpu->irq = platform_get_irq_byname(pdev, irqname);
        if (gpu->irq < 0) {
                ret = gpu->irq;
                dev_err(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) {
                dev_err(drm->dev, "failed to request IRQ%u: %d\n", gpu->irq, ret);
                goto fail;
        }

        /* Acquire clocks: */
        for (i = 0; i < ARRAY_SIZE(clk_names); i++) {
                gpu->grp_clks[i] = devm_clk_get(&pdev->dev, clk_names[i]);
                DBG("grp_clks[%s]: %p", clk_names[i], gpu->grp_clks[i]);
                if (IS_ERR(gpu->grp_clks[i]))
                        gpu->grp_clks[i] = NULL;
        }

        gpu->ebi1_clk = devm_clk_get(&pdev->dev, "bus_clk");
        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;

        /* Setup IOMMU.. eventually we will (I think) do this once per context
         * and have separate page tables per context.  For now, to keep things
         * simple and to get something working, just use a single address space:
         */
        iommu = iommu_domain_alloc(&platform_bus_type);
        if (iommu) {
                dev_info(drm->dev, "%s: using IOMMU\n", name);
                gpu->mmu = msm_iommu_new(&pdev->dev, iommu);
                if (IS_ERR(gpu->mmu)) {
                        ret = PTR_ERR(gpu->mmu);
                        dev_err(drm->dev, "failed to init iommu: %d\n", ret);
                        gpu->mmu = NULL;
                        iommu_domain_free(iommu);
                        goto fail;
                }

        } else {
                dev_info(drm->dev, "%s: no IOMMU, fallback to VRAM carveout!\n", name);
        }
        gpu->id = msm_register_mmu(drm, gpu->mmu);


        /* Create ringbuffer: */
        mutex_lock(&drm->struct_mutex);
        gpu->rb = msm_ringbuffer_new(gpu, ringsz);
        mutex_unlock(&drm->struct_mutex);
        if (IS_ERR(gpu->rb)) {
                ret = PTR_ERR(gpu->rb);
                gpu->rb = NULL;
                dev_err(drm->dev, "could not create ringbuffer: %d\n", ret);
                goto fail;
        }

        bs_init(gpu);

        return 0;

fail:
        return ret;
}

void msm_gpu_cleanup(struct msm_gpu *gpu)
{
        DBG("%s", gpu->name);

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

        bs_fini(gpu);

        if (gpu->rb) {
                if (gpu->rb_iova)
                        msm_gem_put_iova(gpu->rb->bo, gpu->id);
                msm_ringbuffer_destroy(gpu->rb);
        }

        if (gpu->mmu)
                gpu->mmu->funcs->destroy(gpu->mmu);

        if (gpu->fctx)
                msm_fence_context_free(gpu->fctx);
}