1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * vivid-cec.c - A Virtual Video Test Driver, cec emulation
4 *
5 * Copyright 2016 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
6 */
7
8 #include <media/cec.h>
9
10 #include "vivid-core.h"
11 #include "vivid-cec.h"
12
13 #define CEC_TIM_START_BIT_TOTAL 4500
14 #define CEC_TIM_START_BIT_LOW 3700
15 #define CEC_TIM_START_BIT_HIGH 800
16 #define CEC_TIM_DATA_BIT_TOTAL 2400
17 #define CEC_TIM_DATA_BIT_0_LOW 1500
18 #define CEC_TIM_DATA_BIT_0_HIGH 900
19 #define CEC_TIM_DATA_BIT_1_LOW 600
20 #define CEC_TIM_DATA_BIT_1_HIGH 1800
21
vivid_cec_bus_free_work(struct vivid_dev * dev)22 void vivid_cec_bus_free_work(struct vivid_dev *dev)
23 {
24 spin_lock(&dev->cec_slock);
25 while (!list_empty(&dev->cec_work_list)) {
26 struct vivid_cec_work *cw =
27 list_first_entry(&dev->cec_work_list,
28 struct vivid_cec_work, list);
29
30 spin_unlock(&dev->cec_slock);
31 cancel_delayed_work_sync(&cw->work);
32 spin_lock(&dev->cec_slock);
33 list_del(&cw->list);
34 cec_transmit_attempt_done(cw->adap, CEC_TX_STATUS_LOW_DRIVE);
35 kfree(cw);
36 }
37 spin_unlock(&dev->cec_slock);
38 }
39
vivid_cec_find_dest_adap(struct vivid_dev * dev,struct cec_adapter * adap,u8 dest)40 static bool vivid_cec_find_dest_adap(struct vivid_dev *dev,
41 struct cec_adapter *adap, u8 dest)
42 {
43 unsigned int i;
44
45 if (dest >= 0xf)
46 return false;
47
48 if (adap != dev->cec_rx_adap && dev->cec_rx_adap &&
49 dev->cec_rx_adap->is_configured &&
50 cec_has_log_addr(dev->cec_rx_adap, dest))
51 return true;
52
53 for (i = 0; i < MAX_OUTPUTS && dev->cec_tx_adap[i]; i++) {
54 if (adap == dev->cec_tx_adap[i])
55 continue;
56 if (!dev->cec_tx_adap[i]->is_configured)
57 continue;
58 if (cec_has_log_addr(dev->cec_tx_adap[i], dest))
59 return true;
60 }
61 return false;
62 }
63
vivid_cec_pin_adap_events(struct cec_adapter * adap,ktime_t ts,const struct cec_msg * msg,bool nacked)64 static void vivid_cec_pin_adap_events(struct cec_adapter *adap, ktime_t ts,
65 const struct cec_msg *msg, bool nacked)
66 {
67 unsigned int len = nacked ? 1 : msg->len;
68 unsigned int i;
69 bool bit;
70
71 if (adap == NULL)
72 return;
73
74 /*
75 * Suffix ULL on constant 10 makes the expression
76 * CEC_TIM_START_BIT_TOTAL + 10ULL * len * CEC_TIM_DATA_BIT_TOTAL
77 * to be evaluated using 64-bit unsigned arithmetic (u64), which
78 * is what ktime_sub_us expects as second argument.
79 */
80 ts = ktime_sub_us(ts, CEC_TIM_START_BIT_TOTAL +
81 10ULL * len * CEC_TIM_DATA_BIT_TOTAL);
82 cec_queue_pin_cec_event(adap, false, false, ts);
83 ts = ktime_add_us(ts, CEC_TIM_START_BIT_LOW);
84 cec_queue_pin_cec_event(adap, true, false, ts);
85 ts = ktime_add_us(ts, CEC_TIM_START_BIT_HIGH);
86
87 for (i = 0; i < 10 * len; i++) {
88 switch (i % 10) {
89 case 0 ... 7:
90 bit = msg->msg[i / 10] & (0x80 >> (i % 10));
91 break;
92 case 8: /* EOM */
93 bit = i / 10 == msg->len - 1;
94 break;
95 case 9: /* ACK */
96 bit = cec_msg_is_broadcast(msg) ^ nacked;
97 break;
98 }
99 cec_queue_pin_cec_event(adap, false, false, ts);
100 if (bit)
101 ts = ktime_add_us(ts, CEC_TIM_DATA_BIT_1_LOW);
102 else
103 ts = ktime_add_us(ts, CEC_TIM_DATA_BIT_0_LOW);
104 cec_queue_pin_cec_event(adap, true, false, ts);
105 if (bit)
106 ts = ktime_add_us(ts, CEC_TIM_DATA_BIT_1_HIGH);
107 else
108 ts = ktime_add_us(ts, CEC_TIM_DATA_BIT_0_HIGH);
109 }
110 }
111
vivid_cec_pin_events(struct vivid_dev * dev,const struct cec_msg * msg,bool nacked)112 static void vivid_cec_pin_events(struct vivid_dev *dev,
113 const struct cec_msg *msg, bool nacked)
114 {
115 ktime_t ts = ktime_get();
116 unsigned int i;
117
118 vivid_cec_pin_adap_events(dev->cec_rx_adap, ts, msg, nacked);
119 for (i = 0; i < MAX_OUTPUTS; i++)
120 vivid_cec_pin_adap_events(dev->cec_tx_adap[i], ts, msg, nacked);
121 }
122
vivid_cec_xfer_done_worker(struct work_struct * work)123 static void vivid_cec_xfer_done_worker(struct work_struct *work)
124 {
125 struct vivid_cec_work *cw =
126 container_of(work, struct vivid_cec_work, work.work);
127 struct vivid_dev *dev = cw->dev;
128 struct cec_adapter *adap = cw->adap;
129 u8 dest = cec_msg_destination(&cw->msg);
130 bool valid_dest;
131 unsigned int i;
132
133 valid_dest = cec_msg_is_broadcast(&cw->msg);
134 if (!valid_dest)
135 valid_dest = vivid_cec_find_dest_adap(dev, adap, dest);
136
137 cw->tx_status = valid_dest ? CEC_TX_STATUS_OK : CEC_TX_STATUS_NACK;
138 spin_lock(&dev->cec_slock);
139 dev->cec_xfer_time_jiffies = 0;
140 dev->cec_xfer_start_jiffies = 0;
141 list_del(&cw->list);
142 spin_unlock(&dev->cec_slock);
143 vivid_cec_pin_events(dev, &cw->msg, !valid_dest);
144 cec_transmit_attempt_done(cw->adap, cw->tx_status);
145
146 /* Broadcast message */
147 if (adap != dev->cec_rx_adap)
148 cec_received_msg(dev->cec_rx_adap, &cw->msg);
149 for (i = 0; i < MAX_OUTPUTS && dev->cec_tx_adap[i]; i++)
150 if (adap != dev->cec_tx_adap[i])
151 cec_received_msg(dev->cec_tx_adap[i], &cw->msg);
152 kfree(cw);
153 }
154
vivid_cec_xfer_try_worker(struct work_struct * work)155 static void vivid_cec_xfer_try_worker(struct work_struct *work)
156 {
157 struct vivid_cec_work *cw =
158 container_of(work, struct vivid_cec_work, work.work);
159 struct vivid_dev *dev = cw->dev;
160
161 spin_lock(&dev->cec_slock);
162 if (dev->cec_xfer_time_jiffies) {
163 list_del(&cw->list);
164 spin_unlock(&dev->cec_slock);
165 cec_transmit_attempt_done(cw->adap, CEC_TX_STATUS_ARB_LOST);
166 kfree(cw);
167 } else {
168 INIT_DELAYED_WORK(&cw->work, vivid_cec_xfer_done_worker);
169 dev->cec_xfer_start_jiffies = jiffies;
170 dev->cec_xfer_time_jiffies = usecs_to_jiffies(cw->usecs);
171 spin_unlock(&dev->cec_slock);
172 schedule_delayed_work(&cw->work, dev->cec_xfer_time_jiffies);
173 }
174 }
175
vivid_cec_adap_enable(struct cec_adapter * adap,bool enable)176 static int vivid_cec_adap_enable(struct cec_adapter *adap, bool enable)
177 {
178 adap->cec_pin_is_high = true;
179 return 0;
180 }
181
vivid_cec_adap_log_addr(struct cec_adapter * adap,u8 log_addr)182 static int vivid_cec_adap_log_addr(struct cec_adapter *adap, u8 log_addr)
183 {
184 return 0;
185 }
186
187 /*
188 * One data bit takes 2400 us, each byte needs 10 bits so that's 24000 us
189 * per byte.
190 */
191 #define USECS_PER_BYTE 24000
192
vivid_cec_adap_transmit(struct cec_adapter * adap,u8 attempts,u32 signal_free_time,struct cec_msg * msg)193 static int vivid_cec_adap_transmit(struct cec_adapter *adap, u8 attempts,
194 u32 signal_free_time, struct cec_msg *msg)
195 {
196 struct vivid_dev *dev = cec_get_drvdata(adap);
197 struct vivid_cec_work *cw = kzalloc(sizeof(*cw), GFP_KERNEL);
198 long delta_jiffies = 0;
199
200 if (cw == NULL)
201 return -ENOMEM;
202 cw->dev = dev;
203 cw->adap = adap;
204 cw->usecs = CEC_FREE_TIME_TO_USEC(signal_free_time) +
205 msg->len * USECS_PER_BYTE;
206 cw->msg = *msg;
207
208 spin_lock(&dev->cec_slock);
209 list_add(&cw->list, &dev->cec_work_list);
210 if (dev->cec_xfer_time_jiffies == 0) {
211 INIT_DELAYED_WORK(&cw->work, vivid_cec_xfer_done_worker);
212 dev->cec_xfer_start_jiffies = jiffies;
213 dev->cec_xfer_time_jiffies = usecs_to_jiffies(cw->usecs);
214 delta_jiffies = dev->cec_xfer_time_jiffies;
215 } else {
216 INIT_DELAYED_WORK(&cw->work, vivid_cec_xfer_try_worker);
217 delta_jiffies = dev->cec_xfer_start_jiffies +
218 dev->cec_xfer_time_jiffies - jiffies;
219 }
220 spin_unlock(&dev->cec_slock);
221 schedule_delayed_work(&cw->work, delta_jiffies < 0 ? 0 : delta_jiffies);
222 return 0;
223 }
224
vivid_received(struct cec_adapter * adap,struct cec_msg * msg)225 static int vivid_received(struct cec_adapter *adap, struct cec_msg *msg)
226 {
227 struct vivid_dev *dev = cec_get_drvdata(adap);
228 struct cec_msg reply;
229 u8 dest = cec_msg_destination(msg);
230 u8 disp_ctl;
231 char osd[14];
232
233 if (cec_msg_is_broadcast(msg))
234 dest = adap->log_addrs.log_addr[0];
235 cec_msg_init(&reply, dest, cec_msg_initiator(msg));
236
237 switch (cec_msg_opcode(msg)) {
238 case CEC_MSG_SET_OSD_STRING:
239 if (!cec_is_sink(adap))
240 return -ENOMSG;
241 cec_ops_set_osd_string(msg, &disp_ctl, osd);
242 switch (disp_ctl) {
243 case CEC_OP_DISP_CTL_DEFAULT:
244 strscpy(dev->osd, osd, sizeof(dev->osd));
245 dev->osd_jiffies = jiffies;
246 break;
247 case CEC_OP_DISP_CTL_UNTIL_CLEARED:
248 strscpy(dev->osd, osd, sizeof(dev->osd));
249 dev->osd_jiffies = 0;
250 break;
251 case CEC_OP_DISP_CTL_CLEAR:
252 dev->osd[0] = 0;
253 dev->osd_jiffies = 0;
254 break;
255 default:
256 cec_msg_feature_abort(&reply, cec_msg_opcode(msg),
257 CEC_OP_ABORT_INVALID_OP);
258 cec_transmit_msg(adap, &reply, false);
259 break;
260 }
261 break;
262 default:
263 return -ENOMSG;
264 }
265 return 0;
266 }
267
268 static const struct cec_adap_ops vivid_cec_adap_ops = {
269 .adap_enable = vivid_cec_adap_enable,
270 .adap_log_addr = vivid_cec_adap_log_addr,
271 .adap_transmit = vivid_cec_adap_transmit,
272 .received = vivid_received,
273 };
274
vivid_cec_alloc_adap(struct vivid_dev * dev,unsigned int idx,bool is_source)275 struct cec_adapter *vivid_cec_alloc_adap(struct vivid_dev *dev,
276 unsigned int idx,
277 bool is_source)
278 {
279 char name[sizeof(dev->vid_out_dev.name) + 2];
280 u32 caps = CEC_CAP_DEFAULTS | CEC_CAP_MONITOR_ALL | CEC_CAP_MONITOR_PIN;
281
282 snprintf(name, sizeof(name), "%s%d",
283 is_source ? dev->vid_out_dev.name : dev->vid_cap_dev.name,
284 idx);
285 return cec_allocate_adapter(&vivid_cec_adap_ops, dev,
286 name, caps, 1);
287 }
288
