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