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		while (time_is_after_jiffies(cur_jiffies + wait_jiffies) &&
139		       !kthread_should_stop())
140			schedule();
141	}
142	dprintk(dev, 1, "Touch Capture Thread End\n");
143	return 0;
144}
145
146int vivid_start_generating_touch_cap(struct vivid_dev *dev)
147{
148	if (dev->kthread_touch_cap) {
149		dev->touch_cap_streaming = true;
150		return 0;
151	}
152
153	dev->touch_cap_seq_start = dev->seq_wrap * 128;
154	dev->kthread_touch_cap = kthread_run(vivid_thread_touch_cap, dev,
155					     "%s-tch-cap", dev->v4l2_dev.name);
156
157	if (IS_ERR(dev->kthread_touch_cap)) {
158		int err = PTR_ERR(dev->kthread_touch_cap);
159
160		dev->kthread_touch_cap = NULL;
161		v4l2_err(&dev->v4l2_dev, "kernel_thread() failed\n");
162		return err;
163	}
164	dev->touch_cap_streaming = true;
165	dprintk(dev, 1, "returning from %s\n", __func__);
166	return 0;
167}
168
169void vivid_stop_generating_touch_cap(struct vivid_dev *dev)
170{
171	if (!dev->kthread_touch_cap)
172		return;
173
174	dev->touch_cap_streaming = false;
175
176	while (!list_empty(&dev->touch_cap_active)) {
177		struct vivid_buffer *buf;
178
179		buf = list_entry(dev->touch_cap_active.next,
180				 struct vivid_buffer, list);
181		list_del(&buf->list);
182		v4l2_ctrl_request_complete(buf->vb.vb2_buf.req_obj.req,
183					   &dev->ctrl_hdl_touch_cap);
184		vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
185		dprintk(dev, 2, "touch_cap buffer %d done\n",
186			buf->vb.vb2_buf.index);
187	}
188
189	kthread_stop(dev->kthread_touch_cap);
190	dev->kthread_touch_cap = NULL;
191}
192