vivid-kthread-touch.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * vivid-kthread-touch.c - touch capture thread support functions.
  4 *
  5 */
  6
  7#include <linux/freezer.h>
  8#include <linux/jiffies.h>
  9#include "vivid-core.h"
 10#include "vivid-kthread-touch.h"
 11#include "vivid-touch-cap.h"
 12
 13static noinline_for_stack void vivid_thread_tch_cap_tick(struct vivid_dev *dev,
 14							 int dropped_bufs)
 15{
 16	struct vivid_buffer *tch_cap_buf = NULL;
 17
 18	spin_lock(&dev->slock);
 19	if (!list_empty(&dev->touch_cap_active)) {
 20		tch_cap_buf = list_entry(dev->touch_cap_active.next,
 21					 struct vivid_buffer, list);
 22		list_del(&tch_cap_buf->list);
 23	}
 24
 25	spin_unlock(&dev->slock);
 26
 27	if (tch_cap_buf) {
 28		v4l2_ctrl_request_setup(tch_cap_buf->vb.vb2_buf.req_obj.req,
 29					&dev->ctrl_hdl_touch_cap);
 30
 31		vivid_fillbuff_tch(dev, tch_cap_buf);
 32		v4l2_ctrl_request_complete(tch_cap_buf->vb.vb2_buf.req_obj.req,
 33					   &dev->ctrl_hdl_touch_cap);
 34		vb2_buffer_done(&tch_cap_buf->vb.vb2_buf, dev->dqbuf_error ?
 35				VB2_BUF_STATE_ERROR : VB2_BUF_STATE_DONE);
 36		dprintk(dev, 2, "touch_cap buffer %d done\n",
 37			tch_cap_buf->vb.vb2_buf.index);
 38
 39		tch_cap_buf->vb.vb2_buf.timestamp = ktime_get_ns() + dev->time_wrap_offset;
 40	}
 41	dev->dqbuf_error = false;
 42}
 43
 44static int vivid_thread_touch_cap(void *data)
 45{
 46	struct vivid_dev *dev = data;
 47	u64 numerators_since_start;
 48	u64 buffers_since_start;
 49	u64 next_jiffies_since_start;
 50	unsigned long jiffies_since_start;
 51	unsigned long cur_jiffies;
 52	unsigned int wait_jiffies;
 53	unsigned int numerator;
 54	unsigned int denominator;
 55	int dropped_bufs;
 56
 57	dprintk(dev, 1, "Touch Capture Thread Start\n");
 58
 59	set_freezable();
 60
 61	/* Resets frame counters */
 62	dev->touch_cap_seq_offset = 0;
 63	dev->touch_cap_seq_count = 0;
 64	dev->touch_cap_seq_resync = false;
 65	dev->jiffies_touch_cap = jiffies;
 66	if (dev->time_wrap)
 67		dev->time_wrap_offset = dev->time_wrap - ktime_get_ns();
 68	else
 69		dev->time_wrap_offset = 0;
 70
 71	for (;;) {
 72		try_to_freeze();
 73		if (kthread_should_stop())
 74			break;
 75
 76		if (!mutex_trylock(&dev->mutex)) {
 77			schedule();
 78			continue;
 79		}
 80		cur_jiffies = jiffies;
 81		if (dev->touch_cap_seq_resync) {
 82			dev->jiffies_touch_cap = cur_jiffies;
 83			dev->touch_cap_seq_offset = dev->touch_cap_seq_count + 1;
 84			dev->touch_cap_seq_count = 0;
 85			dev->cap_seq_resync = false;
 86		}
 87		denominator = dev->timeperframe_tch_cap.denominator;
 88		numerator = dev->timeperframe_tch_cap.numerator;
 89
 90		/* Calculate the number of jiffies since we started streaming */
 91		jiffies_since_start = cur_jiffies - dev->jiffies_touch_cap;
 92		/* Get the number of buffers streamed since the start */
 93		buffers_since_start = (u64)jiffies_since_start * denominator +
 94				      (HZ * numerator) / 2;
 95		do_div(buffers_since_start, HZ * numerator);
 96
 97		/*
 98		 * After more than 0xf0000000 (rounded down to a multiple of
 99		 * 'jiffies-per-day' to ease jiffies_to_msecs calculation)
100		 * jiffies have passed since we started streaming reset the
101		 * counters and keep track of the sequence offset.
102		 */
103		if (jiffies_since_start > JIFFIES_RESYNC) {
104			dev->jiffies_touch_cap = cur_jiffies;
105			dev->cap_seq_offset = buffers_since_start;
106			buffers_since_start = 0;
107		}
108		dropped_bufs = buffers_since_start + dev->touch_cap_seq_offset - dev->touch_cap_seq_count;
109		dev->touch_cap_seq_count = buffers_since_start + dev->touch_cap_seq_offset;
110		dev->touch_cap_with_seq_wrap_count =
111			dev->touch_cap_seq_count - dev->touch_cap_seq_start;
112
113		vivid_thread_tch_cap_tick(dev, dropped_bufs);
114
115		/*
116		 * Calculate the number of 'numerators' streamed
117		 * since we started, including the current buffer.
118		 */
119		numerators_since_start = ++buffers_since_start * numerator;
120
121		/* And the number of jiffies since we started */
122		jiffies_since_start = jiffies - dev->jiffies_touch_cap;
123
124		mutex_unlock(&dev->mutex);
125
126		/*
127		 * Calculate when that next buffer is supposed to start
128		 * in jiffies since we started streaming.
129		 */
130		next_jiffies_since_start = numerators_since_start * HZ +
131					   denominator / 2;
132		do_div(next_jiffies_since_start, denominator);
133		/* If it is in the past, then just schedule asap */
134		if (next_jiffies_since_start < jiffies_since_start)
135			next_jiffies_since_start = jiffies_since_start;
136
137		wait_jiffies = next_jiffies_since_start - jiffies_since_start;
138		if (!time_is_after_jiffies(cur_jiffies + wait_jiffies))
139			continue;
140
141		wait_queue_head_t wait;
142
143		init_waitqueue_head(&wait);
144		wait_event_interruptible_timeout(wait, kthread_should_stop(),
145					cur_jiffies + wait_jiffies - jiffies);
146	}
147	dprintk(dev, 1, "Touch Capture Thread End\n");
148	return 0;
149}
150
151int vivid_start_generating_touch_cap(struct vivid_dev *dev)
152{
153	if (dev->kthread_touch_cap) {
154		dev->touch_cap_streaming = true;
155		return 0;
156	}
157
158	dev->touch_cap_seq_start = dev->seq_wrap * 128;
159	dev->kthread_touch_cap = kthread_run(vivid_thread_touch_cap, dev,
160					     "%s-tch-cap", dev->v4l2_dev.name);
161
162	if (IS_ERR(dev->kthread_touch_cap)) {
163		int err = PTR_ERR(dev->kthread_touch_cap);
164
165		dev->kthread_touch_cap = NULL;
166		v4l2_err(&dev->v4l2_dev, "kernel_thread() failed\n");
167		return err;
168	}
169	dev->touch_cap_streaming = true;
170	dprintk(dev, 1, "returning from %s\n", __func__);
171	return 0;
172}
173
174void vivid_stop_generating_touch_cap(struct vivid_dev *dev)
175{
176	if (!dev->kthread_touch_cap)
177		return;
178
179	dev->touch_cap_streaming = false;
180
181	while (!list_empty(&dev->touch_cap_active)) {
182		struct vivid_buffer *buf;
183
184		buf = list_entry(dev->touch_cap_active.next,
185				 struct vivid_buffer, list);
186		list_del(&buf->list);
187		v4l2_ctrl_request_complete(buf->vb.vb2_buf.req_obj.req,
188					   &dev->ctrl_hdl_touch_cap);
189		vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
190		dprintk(dev, 2, "touch_cap buffer %d done\n",
191			buf->vb.vb2_buf.index);
192	}
193
194	kthread_stop(dev->kthread_touch_cap);
195	dev->kthread_touch_cap = NULL;
196}