// SPDX-License-Identifier: GPL-2.0-only
/*
 * vivid-kthread-touch.c - touch capture thread support functions.
 *
 */

#include <linux/freezer.h>
#include <linux/jiffies.h>
#include "vivid-core.h"
#include "vivid-kthread-touch.h"
#include "vivid-touch-cap.h"

static noinline_for_stack void vivid_thread_tch_cap_tick(struct vivid_dev *dev,
        int dropped_bufs)
{
 struct vivid_buffer *tch_cap_buf = NULL;

 spin_lock(&dev->slock);
 if (!list_empty(&dev->touch_cap_active)) {
  tch_cap_buf = list_entry(dev->touch_cap_active.next,
      struct vivid_buffer, list);
  list_del(&tch_cap_buf->list);
 }

 spin_unlock(&dev->slock);

 if (tch_cap_buf) {
  v4l2_ctrl_request_setup(tch_cap_buf->vb.vb2_buf.req_obj.req,
     &dev->ctrl_hdl_touch_cap);

  vivid_fillbuff_tch(dev, tch_cap_buf);
  v4l2_ctrl_request_complete(tch_cap_buf->vb.vb2_buf.req_obj.req,
        &dev->ctrl_hdl_touch_cap);
  vb2_buffer_done(&tch_cap_buf->vb.vb2_buf, dev->dqbuf_error ?
    VB2_BUF_STATE_ERROR : VB2_BUF_STATE_DONE);
  dprintk(dev, 2, "touch_cap buffer %d done\n",
   tch_cap_buf->vb.vb2_buf.index);

  tch_cap_buf->vb.vb2_buf.timestamp = ktime_get_ns() + dev->time_wrap_offset;
 }
 dev->dqbuf_error = false;
}

static int vivid_thread_touch_cap(void *data)
{
 struct vivid_dev *dev = data;
 u64 numerators_since_start;
 u64 buffers_since_start;
 u64 next_jiffies_since_start;
 unsigned long jiffies_since_start;
 unsigned long cur_jiffies;
 unsigned int wait_jiffies;
 unsigned int numerator;
 unsigned int denominator;
 int dropped_bufs;

 dprintk(dev, 1, "Touch Capture Thread Start\n");

 set_freezable();

 /* Resets frame counters */
 dev->touch_cap_seq_offset = 0;
 dev->touch_cap_seq_count = 0;
 dev->touch_cap_seq_resync = false;
 dev->jiffies_touch_cap = jiffies;
 if (dev->time_wrap)
  dev->time_wrap_offset = dev->time_wrap - ktime_get_ns();
 else
  dev->time_wrap_offset = 0;

 for (;;) {
  try_to_freeze();
  if (kthread_should_stop())
   break;

  if (!mutex_trylock(&dev->mutex)) {
   schedule();
   continue;
  }
  cur_jiffies = jiffies;
  if (dev->touch_cap_seq_resync) {
   dev->jiffies_touch_cap = cur_jiffies;
   dev->touch_cap_seq_offset = dev->touch_cap_seq_count + 1;
   dev->touch_cap_seq_count = 0;
   dev->cap_seq_resync = false;
  }
  denominator = dev->timeperframe_tch_cap.denominator;
  numerator = dev->timeperframe_tch_cap.numerator;

  /* Calculate the number of jiffies since we started streaming */
  jiffies_since_start = cur_jiffies - dev->jiffies_touch_cap;
  /* Get the number of buffers streamed since the start */
  buffers_since_start = (u64)jiffies_since_start * denominator +
          (HZ * numerator) / 2;
  do_div(buffers_since_start, HZ * numerator);

  /*
   * After more than 0xf0000000 (rounded down to a multiple of
   * 'jiffies-per-day' to ease jiffies_to_msecs calculation)
   * jiffies have passed since we started streaming reset the
   * counters and keep track of the sequence offset.
 */
  if (jiffies_since_start > JIFFIES_RESYNC) {
   dev->jiffies_touch_cap = cur_jiffies;
   dev->cap_seq_offset = buffers_since_start;
   buffers_since_start = 0;
  }
  dropped_bufs = buffers_since_start + dev->touch_cap_seq_offset - dev->touch_cap_seq_count;
  dev->touch_cap_seq_count = buffers_since_start + dev->touch_cap_seq_offset;
  dev->touch_cap_with_seq_wrap_count =
   dev->touch_cap_seq_count - dev->touch_cap_seq_start;

  vivid_thread_tch_cap_tick(dev, dropped_bufs);

  /*
   * Calculate the number of 'numerators' streamed
   * since we started, including the current buffer.
 */
  numerators_since_start = ++buffers_since_start * numerator;

  /* And the number of jiffies since we started */
  jiffies_since_start = jiffies - dev->jiffies_touch_cap;

  mutex_unlock(&dev->mutex);

  /*
   * Calculate when that next buffer is supposed to start
   * in jiffies since we started streaming.
 */
  next_jiffies_since_start = numerators_since_start * HZ +
        denominator / 2;
  do_div(next_jiffies_since_start, denominator);
  /* If it is in the past, then just schedule asap */
  if (next_jiffies_since_start < jiffies_since_start)
   next_jiffies_since_start = jiffies_since_start;

  wait_jiffies = next_jiffies_since_start - jiffies_since_start;
  if (!time_is_after_jiffies(cur_jiffies + wait_jiffies))
   continue;

  wait_queue_head_t wait;

  init_waitqueue_head(&wait);
  wait_event_interruptible_timeout(wait, kthread_should_stop(),
     cur_jiffies + wait_jiffies - jiffies);
 }
 dprintk(dev, 1, "Touch Capture Thread End\n");
 return 0;
}

int vivid_start_generating_touch_cap(struct vivid_dev *dev)
{
 if (dev->kthread_touch_cap) {
  dev->touch_cap_streaming = true;
  return 0;
 }

 dev->touch_cap_seq_start = dev->seq_wrap * 128;
 dev->kthread_touch_cap = kthread_run(vivid_thread_touch_cap, dev,
          "%s-tch-cap", dev->v4l2_dev.name);

 if (IS_ERR(dev->kthread_touch_cap)) {
  int err = PTR_ERR(dev->kthread_touch_cap);

  dev->kthread_touch_cap = NULL;
  v4l2_err(&dev->v4l2_dev, "kernel_thread() failed\n");
  return err;
 }
 dev->touch_cap_streaming = true;
 dprintk(dev, 1, "returning from %s\n", __func__);
 return 0;
}

void vivid_stop_generating_touch_cap(struct vivid_dev *dev)
{
 if (!dev->kthread_touch_cap)
  return;

 dev->touch_cap_streaming = false;

 while (!list_empty(&dev->touch_cap_active)) {
  struct vivid_buffer *buf;

  buf = list_entry(dev->touch_cap_active.next,
     struct vivid_buffer, list);
  list_del(&buf->list);
  v4l2_ctrl_request_complete(buf->vb.vb2_buf.req_obj.req,
        &dev->ctrl_hdl_touch_cap);
  vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
  dprintk(dev, 2, "touch_cap buffer %d done\n",
   buf->vb.vb2_buf.index);
 }

 kthread_stop(dev->kthread_touch_cap);
 dev->kthread_touch_cap = NULL;
}