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 
12 static 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 
43 static 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();
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 		while (jiffies - cur_jiffies < wait_jiffies &&
132 		       !kthread_should_stop())
133 			schedule();
134 	}
135 	dprintk(dev, 1, "Touch Capture Thread End\n");
136 	return 0;
137 }
138 
139 int vivid_start_generating_touch_cap(struct vivid_dev *dev)
140 {
141 	if (dev->kthread_touch_cap) {
142 		dev->touch_cap_streaming = true;
143 		return 0;
144 	}
145 
146 	dev->kthread_touch_cap = kthread_run(vivid_thread_touch_cap, dev,
147 					     "%s-tch-cap", dev->v4l2_dev.name);
148 
149 	if (IS_ERR(dev->kthread_touch_cap)) {
150 		int err = PTR_ERR(dev->kthread_touch_cap);
151 
152 		dev->kthread_touch_cap = NULL;
153 		v4l2_err(&dev->v4l2_dev, "kernel_thread() failed\n");
154 		return err;
155 	}
156 	dev->touch_cap_streaming = true;
157 	dprintk(dev, 1, "returning from %s\n", __func__);
158 	return 0;
159 }
160 
161 void vivid_stop_generating_touch_cap(struct vivid_dev *dev)
162 {
163 	if (!dev->kthread_touch_cap)
164 		return;
165 
166 	dev->touch_cap_streaming = false;
167 
168 	while (!list_empty(&dev->touch_cap_active)) {
169 		struct vivid_buffer *buf;
170 
171 		buf = list_entry(dev->touch_cap_active.next,
172 				 struct vivid_buffer, list);
173 		list_del(&buf->list);
174 		v4l2_ctrl_request_complete(buf->vb.vb2_buf.req_obj.req,
175 					   &dev->ctrl_hdl_touch_cap);
176 		vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
177 		dprintk(dev, 2, "touch_cap buffer %d done\n",
178 			buf->vb.vb2_buf.index);
179 	}
180 
181 	kthread_stop(dev->kthread_touch_cap);
182 	dev->kthread_touch_cap = NULL;
183 }
184