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

#include <linux/freezer.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;

        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;

                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;
                while (jiffies - cur_jiffies < wait_jiffies &&
                       !kthread_should_stop())
                        schedule();
        }
        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->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;
}