// SPDX-License-Identifier: GPL-2.0 OR MIT
/**************************************************************************
 *
 * Copyright 2009-2015 VMware, Inc., Palo Alto, CA., USA
 *
 * 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, sub license, 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 NON-INFRINGEMENT. IN NO EVENT SHALL
 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS 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 <linux/sched/signal.h>

#include "vmwgfx_drv.h"

#define VMW_FENCE_WRAP (1 << 24)

/**
 * vmw_thread_fn - Deferred (process context) irq handler
 *
 * @irq: irq number
 * @arg: Closure argument. Pointer to a struct drm_device cast to void *
 *
 * This function implements the deferred part of irq processing.
 * The function is guaranteed to run at least once after the
 * vmw_irq_handler has returned with IRQ_WAKE_THREAD.
 *
 */
static irqreturn_t vmw_thread_fn(int irq, void *arg)
{
        struct drm_device *dev = (struct drm_device *)arg;
        struct vmw_private *dev_priv = vmw_priv(dev);
        irqreturn_t ret = IRQ_NONE;

        if (test_and_clear_bit(VMW_IRQTHREAD_FENCE,
                               dev_priv->irqthread_pending)) {
                vmw_fences_update(dev_priv->fman);
                wake_up_all(&dev_priv->fence_queue);
                ret = IRQ_HANDLED;
        }

        if (test_and_clear_bit(VMW_IRQTHREAD_CMDBUF,
                               dev_priv->irqthread_pending)) {
                vmw_cmdbuf_irqthread(dev_priv->cman);
                ret = IRQ_HANDLED;
        }

        return ret;
}

/**
 * vmw_irq_handler irq handler
 *
 * @irq: irq number
 * @arg: Closure argument. Pointer to a struct drm_device cast to void *
 *
 * This function implements the quick part of irq processing.
 * The function performs fast actions like clearing the device interrupt
 * flags and also reasonably quick actions like waking processes waiting for
 * FIFO space. Other IRQ actions are deferred to the IRQ thread.
 */
static irqreturn_t vmw_irq_handler(int irq, void *arg)
{
        struct drm_device *dev = (struct drm_device *)arg;
        struct vmw_private *dev_priv = vmw_priv(dev);
        uint32_t status, masked_status;
        irqreturn_t ret = IRQ_HANDLED;

        status = inl(dev_priv->io_start + VMWGFX_IRQSTATUS_PORT);
        masked_status = status & READ_ONCE(dev_priv->irq_mask);

        if (likely(status))
                outl(status, dev_priv->io_start + VMWGFX_IRQSTATUS_PORT);

        if (!status)
                return IRQ_NONE;

        if (masked_status & SVGA_IRQFLAG_FIFO_PROGRESS)
                wake_up_all(&dev_priv->fifo_queue);

        if ((masked_status & (SVGA_IRQFLAG_ANY_FENCE |
                              SVGA_IRQFLAG_FENCE_GOAL)) &&
            !test_and_set_bit(VMW_IRQTHREAD_FENCE, dev_priv->irqthread_pending))
                ret = IRQ_WAKE_THREAD;

        if ((masked_status & (SVGA_IRQFLAG_COMMAND_BUFFER |
                              SVGA_IRQFLAG_ERROR)) &&
            !test_and_set_bit(VMW_IRQTHREAD_CMDBUF,
                              dev_priv->irqthread_pending))
                ret = IRQ_WAKE_THREAD;

        return ret;
}

static bool vmw_fifo_idle(struct vmw_private *dev_priv, uint32_t seqno)
{

        return (vmw_read(dev_priv, SVGA_REG_BUSY) == 0);
}

void vmw_update_seqno(struct vmw_private *dev_priv,
                         struct vmw_fifo_state *fifo_state)
{
        u32 *fifo_mem = dev_priv->mmio_virt;
        uint32_t seqno = vmw_mmio_read(fifo_mem + SVGA_FIFO_FENCE);

        if (dev_priv->last_read_seqno != seqno) {
                dev_priv->last_read_seqno = seqno;
                vmw_marker_pull(&fifo_state->marker_queue, seqno);
                vmw_fences_update(dev_priv->fman);
        }
}

bool vmw_seqno_passed(struct vmw_private *dev_priv,
                         uint32_t seqno)
{
        struct vmw_fifo_state *fifo_state;
        bool ret;

        if (likely(dev_priv->last_read_seqno - seqno < VMW_FENCE_WRAP))
                return true;

        fifo_state = &dev_priv->fifo;
        vmw_update_seqno(dev_priv, fifo_state);
        if (likely(dev_priv->last_read_seqno - seqno < VMW_FENCE_WRAP))
                return true;

        if (!(fifo_state->capabilities & SVGA_FIFO_CAP_FENCE) &&
            vmw_fifo_idle(dev_priv, seqno))
                return true;

        /**
         * Then check if the seqno is higher than what we've actually
         * emitted. Then the fence is stale and signaled.
         */

        ret = ((atomic_read(&dev_priv->marker_seq) - seqno)
               > VMW_FENCE_WRAP);

        return ret;
}

int vmw_fallback_wait(struct vmw_private *dev_priv,
                      bool lazy,
                      bool fifo_idle,
                      uint32_t seqno,
                      bool interruptible,
                      unsigned long timeout)
{
        struct vmw_fifo_state *fifo_state = &dev_priv->fifo;

        uint32_t count = 0;
        uint32_t signal_seq;
        int ret;
        unsigned long end_jiffies = jiffies + timeout;
        bool (*wait_condition)(struct vmw_private *, uint32_t);
        DEFINE_WAIT(__wait);

        wait_condition = (fifo_idle) ? &vmw_fifo_idle :
                &vmw_seqno_passed;

        /**
         * Block command submission while waiting for idle.
         */

        if (fifo_idle) {
                down_read(&fifo_state->rwsem);
                if (dev_priv->cman) {
                        ret = vmw_cmdbuf_idle(dev_priv->cman, interruptible,
                                              10*HZ);
                        if (ret)
                                goto out_err;
                }
        }

        signal_seq = atomic_read(&dev_priv->marker_seq);
        ret = 0;

        for (;;) {
                prepare_to_wait(&dev_priv->fence_queue, &__wait,
                                (interruptible) ?
                                TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE);
                if (wait_condition(dev_priv, seqno))
                        break;
                if (time_after_eq(jiffies, end_jiffies)) {
                        DRM_ERROR("SVGA device lockup.\n");
                        break;
                }
                if (lazy)
                        schedule_timeout(1);
                else if ((++count & 0x0F) == 0) {
                        /**
                         * FIXME: Use schedule_hr_timeout here for
                         * newer kernels and lower CPU utilization.
                         */

                        __set_current_state(TASK_RUNNING);
                        schedule();
                        __set_current_state((interruptible) ?
                                            TASK_INTERRUPTIBLE :
                                            TASK_UNINTERRUPTIBLE);
                }
                if (interruptible && signal_pending(current)) {
                        ret = -ERESTARTSYS;
                        break;
                }
        }
        finish_wait(&dev_priv->fence_queue, &__wait);
        if (ret == 0 && fifo_idle) {
                u32 *fifo_mem = dev_priv->mmio_virt;

                vmw_mmio_write(signal_seq, fifo_mem + SVGA_FIFO_FENCE);
        }
        wake_up_all(&dev_priv->fence_queue);
out_err:
        if (fifo_idle)
                up_read(&fifo_state->rwsem);

        return ret;
}

void vmw_generic_waiter_add(struct vmw_private *dev_priv,
                            u32 flag, int *waiter_count)
{
        spin_lock_bh(&dev_priv->waiter_lock);
        if ((*waiter_count)++ == 0) {
                outl(flag, dev_priv->io_start + VMWGFX_IRQSTATUS_PORT);
                dev_priv->irq_mask |= flag;
                vmw_write(dev_priv, SVGA_REG_IRQMASK, dev_priv->irq_mask);
        }
        spin_unlock_bh(&dev_priv->waiter_lock);
}

void vmw_generic_waiter_remove(struct vmw_private *dev_priv,
                               u32 flag, int *waiter_count)
{
        spin_lock_bh(&dev_priv->waiter_lock);
        if (--(*waiter_count) == 0) {
                dev_priv->irq_mask &= ~flag;
                vmw_write(dev_priv, SVGA_REG_IRQMASK, dev_priv->irq_mask);
        }
        spin_unlock_bh(&dev_priv->waiter_lock);
}

void vmw_seqno_waiter_add(struct vmw_private *dev_priv)
{
        vmw_generic_waiter_add(dev_priv, SVGA_IRQFLAG_ANY_FENCE,
                               &dev_priv->fence_queue_waiters);
}

void vmw_seqno_waiter_remove(struct vmw_private *dev_priv)
{
        vmw_generic_waiter_remove(dev_priv, SVGA_IRQFLAG_ANY_FENCE,
                                  &dev_priv->fence_queue_waiters);
}

void vmw_goal_waiter_add(struct vmw_private *dev_priv)
{
        vmw_generic_waiter_add(dev_priv, SVGA_IRQFLAG_FENCE_GOAL,
                               &dev_priv->goal_queue_waiters);
}

void vmw_goal_waiter_remove(struct vmw_private *dev_priv)
{
        vmw_generic_waiter_remove(dev_priv, SVGA_IRQFLAG_FENCE_GOAL,
                                  &dev_priv->goal_queue_waiters);
}

int vmw_wait_seqno(struct vmw_private *dev_priv,
                      bool lazy, uint32_t seqno,
                      bool interruptible, unsigned long timeout)
{
        long ret;
        struct vmw_fifo_state *fifo = &dev_priv->fifo;

        if (likely(dev_priv->last_read_seqno - seqno < VMW_FENCE_WRAP))
                return 0;

        if (likely(vmw_seqno_passed(dev_priv, seqno)))
                return 0;

        vmw_fifo_ping_host(dev_priv, SVGA_SYNC_GENERIC);

        if (!(fifo->capabilities & SVGA_FIFO_CAP_FENCE))
                return vmw_fallback_wait(dev_priv, lazy, true, seqno,
                                         interruptible, timeout);

        if (!(dev_priv->capabilities & SVGA_CAP_IRQMASK))
                return vmw_fallback_wait(dev_priv, lazy, false, seqno,
                                         interruptible, timeout);

        vmw_seqno_waiter_add(dev_priv);

        if (interruptible)
                ret = wait_event_interruptible_timeout
                    (dev_priv->fence_queue,
                     vmw_seqno_passed(dev_priv, seqno),
                     timeout);
        else
                ret = wait_event_timeout
                    (dev_priv->fence_queue,
                     vmw_seqno_passed(dev_priv, seqno),
                     timeout);

        vmw_seqno_waiter_remove(dev_priv);

        if (unlikely(ret == 0))
                ret = -EBUSY;
        else if (likely(ret > 0))
                ret = 0;

        return ret;
}

static void vmw_irq_preinstall(struct drm_device *dev)
{
        struct vmw_private *dev_priv = vmw_priv(dev);
        uint32_t status;

        status = inl(dev_priv->io_start + VMWGFX_IRQSTATUS_PORT);
        outl(status, dev_priv->io_start + VMWGFX_IRQSTATUS_PORT);
}

void vmw_irq_uninstall(struct drm_device *dev)
{
        struct vmw_private *dev_priv = vmw_priv(dev);
        uint32_t status;

        if (!(dev_priv->capabilities & SVGA_CAP_IRQMASK))
                return;

        if (!dev->irq_enabled)
                return;

        vmw_write(dev_priv, SVGA_REG_IRQMASK, 0);

        status = inl(dev_priv->io_start + VMWGFX_IRQSTATUS_PORT);
        outl(status, dev_priv->io_start + VMWGFX_IRQSTATUS_PORT);

        dev->irq_enabled = false;
        free_irq(dev->irq, dev);
}

/**
 * vmw_irq_install - Install the irq handlers
 *
 * @dev:  Pointer to the drm device.
 * @irq:  The irq number.
 * Return:  Zero if successful. Negative number otherwise.
 */
int vmw_irq_install(struct drm_device *dev, int irq)
{
        int ret;

        if (dev->irq_enabled)
                return -EBUSY;

        vmw_irq_preinstall(dev);

        ret = request_threaded_irq(irq, vmw_irq_handler, vmw_thread_fn,
                                   IRQF_SHARED, VMWGFX_DRIVER_NAME, dev);
        if (ret < 0)
                return ret;

        dev->irq_enabled = true;
        dev->irq = irq;

        return ret;
}