1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Tegra CEC implementation 4 * 5 * The original 3.10 CEC driver using a custom API: 6 * 7 * Copyright (c) 2012-2015, NVIDIA CORPORATION. All rights reserved. 8 * 9 * Conversion to the CEC framework and to the mainline kernel: 10 * 11 * Copyright 2016-2017 Cisco Systems, Inc. and/or its affiliates. All rights reserved. 12 */ 13 14 #include <linux/module.h> 15 #include <linux/kernel.h> 16 #include <linux/err.h> 17 #include <linux/errno.h> 18 #include <linux/interrupt.h> 19 #include <linux/slab.h> 20 #include <linux/io.h> 21 #include <linux/clk.h> 22 #include <linux/delay.h> 23 #include <linux/pm.h> 24 #include <linux/of.h> 25 #include <linux/of_platform.h> 26 #include <linux/platform_device.h> 27 #include <linux/clk/tegra.h> 28 29 #include <media/cec-notifier.h> 30 31 #include "tegra_cec.h" 32 33 #define TEGRA_CEC_NAME "tegra-cec" 34 35 struct tegra_cec { 36 struct cec_adapter *adap; 37 struct device *dev; 38 struct clk *clk; 39 void __iomem *cec_base; 40 struct cec_notifier *notifier; 41 int tegra_cec_irq; 42 bool rx_done; 43 bool tx_done; 44 int tx_status; 45 u8 rx_buf[CEC_MAX_MSG_SIZE]; 46 u8 rx_buf_cnt; 47 u32 tx_buf[CEC_MAX_MSG_SIZE]; 48 u8 tx_buf_cur; 49 u8 tx_buf_cnt; 50 }; 51 52 static inline u32 cec_read(struct tegra_cec *cec, u32 reg) 53 { 54 return readl(cec->cec_base + reg); 55 } 56 57 static inline void cec_write(struct tegra_cec *cec, u32 reg, u32 val) 58 { 59 writel(val, cec->cec_base + reg); 60 } 61 62 static void tegra_cec_error_recovery(struct tegra_cec *cec) 63 { 64 u32 hw_ctrl; 65 66 hw_ctrl = cec_read(cec, TEGRA_CEC_HW_CONTROL); 67 cec_write(cec, TEGRA_CEC_HW_CONTROL, 0); 68 cec_write(cec, TEGRA_CEC_INT_STAT, 0xffffffff); 69 cec_write(cec, TEGRA_CEC_HW_CONTROL, hw_ctrl); 70 } 71 72 static irqreturn_t tegra_cec_irq_thread_handler(int irq, void *data) 73 { 74 struct device *dev = data; 75 struct tegra_cec *cec = dev_get_drvdata(dev); 76 77 if (cec->tx_done) { 78 cec_transmit_attempt_done(cec->adap, cec->tx_status); 79 cec->tx_done = false; 80 } 81 if (cec->rx_done) { 82 struct cec_msg msg = {}; 83 84 msg.len = cec->rx_buf_cnt; 85 memcpy(msg.msg, cec->rx_buf, msg.len); 86 cec_received_msg(cec->adap, &msg); 87 cec->rx_done = false; 88 cec->rx_buf_cnt = 0; 89 } 90 return IRQ_HANDLED; 91 } 92 93 static irqreturn_t tegra_cec_irq_handler(int irq, void *data) 94 { 95 struct device *dev = data; 96 struct tegra_cec *cec = dev_get_drvdata(dev); 97 u32 status, mask; 98 99 status = cec_read(cec, TEGRA_CEC_INT_STAT); 100 mask = cec_read(cec, TEGRA_CEC_INT_MASK); 101 102 status &= mask; 103 104 if (!status) 105 return IRQ_HANDLED; 106 107 if (status & TEGRA_CEC_INT_STAT_TX_REGISTER_UNDERRUN) { 108 dev_err(dev, "TX underrun, interrupt timing issue!\n"); 109 110 tegra_cec_error_recovery(cec); 111 cec_write(cec, TEGRA_CEC_INT_MASK, 112 mask & ~TEGRA_CEC_INT_MASK_TX_REGISTER_EMPTY); 113 114 cec->tx_done = true; 115 cec->tx_status = CEC_TX_STATUS_ERROR; 116 return IRQ_WAKE_THREAD; 117 } 118 119 if ((status & TEGRA_CEC_INT_STAT_TX_ARBITRATION_FAILED) || 120 (status & TEGRA_CEC_INT_STAT_TX_BUS_ANOMALY_DETECTED)) { 121 tegra_cec_error_recovery(cec); 122 cec_write(cec, TEGRA_CEC_INT_MASK, 123 mask & ~TEGRA_CEC_INT_MASK_TX_REGISTER_EMPTY); 124 125 cec->tx_done = true; 126 if (status & TEGRA_CEC_INT_STAT_TX_BUS_ANOMALY_DETECTED) 127 cec->tx_status = CEC_TX_STATUS_LOW_DRIVE; 128 else 129 cec->tx_status = CEC_TX_STATUS_ARB_LOST; 130 return IRQ_WAKE_THREAD; 131 } 132 133 if (status & TEGRA_CEC_INT_STAT_TX_FRAME_TRANSMITTED) { 134 cec_write(cec, TEGRA_CEC_INT_STAT, 135 TEGRA_CEC_INT_STAT_TX_FRAME_TRANSMITTED); 136 137 if (status & TEGRA_CEC_INT_STAT_TX_FRAME_OR_BLOCK_NAKD) { 138 tegra_cec_error_recovery(cec); 139 140 cec->tx_done = true; 141 cec->tx_status = CEC_TX_STATUS_NACK; 142 } else { 143 cec->tx_done = true; 144 cec->tx_status = CEC_TX_STATUS_OK; 145 } 146 return IRQ_WAKE_THREAD; 147 } 148 149 if (status & TEGRA_CEC_INT_STAT_TX_FRAME_OR_BLOCK_NAKD) 150 dev_warn(dev, "TX NAKed on the fly!\n"); 151 152 if (status & TEGRA_CEC_INT_STAT_TX_REGISTER_EMPTY) { 153 if (cec->tx_buf_cur == cec->tx_buf_cnt) { 154 cec_write(cec, TEGRA_CEC_INT_MASK, 155 mask & ~TEGRA_CEC_INT_MASK_TX_REGISTER_EMPTY); 156 } else { 157 cec_write(cec, TEGRA_CEC_TX_REGISTER, 158 cec->tx_buf[cec->tx_buf_cur++]); 159 cec_write(cec, TEGRA_CEC_INT_STAT, 160 TEGRA_CEC_INT_STAT_TX_REGISTER_EMPTY); 161 } 162 } 163 164 if (status & TEGRA_CEC_INT_STAT_RX_START_BIT_DETECTED) { 165 cec_write(cec, TEGRA_CEC_INT_STAT, 166 TEGRA_CEC_INT_STAT_RX_START_BIT_DETECTED); 167 cec->rx_done = false; 168 cec->rx_buf_cnt = 0; 169 } 170 if (status & TEGRA_CEC_INT_STAT_RX_REGISTER_FULL) { 171 u32 v; 172 173 cec_write(cec, TEGRA_CEC_INT_STAT, 174 TEGRA_CEC_INT_STAT_RX_REGISTER_FULL); 175 v = cec_read(cec, TEGRA_CEC_RX_REGISTER); 176 if (cec->rx_buf_cnt < CEC_MAX_MSG_SIZE) 177 cec->rx_buf[cec->rx_buf_cnt++] = v & 0xff; 178 if (v & TEGRA_CEC_RX_REGISTER_EOM) { 179 cec->rx_done = true; 180 return IRQ_WAKE_THREAD; 181 } 182 } 183 184 return IRQ_HANDLED; 185 } 186 187 static int tegra_cec_adap_enable(struct cec_adapter *adap, bool enable) 188 { 189 struct tegra_cec *cec = adap->priv; 190 191 cec->rx_buf_cnt = 0; 192 cec->tx_buf_cnt = 0; 193 cec->tx_buf_cur = 0; 194 195 cec_write(cec, TEGRA_CEC_HW_CONTROL, 0); 196 cec_write(cec, TEGRA_CEC_INT_MASK, 0); 197 cec_write(cec, TEGRA_CEC_INT_STAT, 0xffffffff); 198 cec_write(cec, TEGRA_CEC_SW_CONTROL, 0); 199 200 if (!enable) 201 return 0; 202 203 cec_write(cec, TEGRA_CEC_INPUT_FILTER, (1U << 31) | 0x20); 204 205 cec_write(cec, TEGRA_CEC_RX_TIMING_0, 206 (0x7a << TEGRA_CEC_RX_TIM0_START_BIT_MAX_LO_TIME_SHIFT) | 207 (0x6d << TEGRA_CEC_RX_TIM0_START_BIT_MIN_LO_TIME_SHIFT) | 208 (0x93 << TEGRA_CEC_RX_TIM0_START_BIT_MAX_DURATION_SHIFT) | 209 (0x86 << TEGRA_CEC_RX_TIM0_START_BIT_MIN_DURATION_SHIFT)); 210 211 cec_write(cec, TEGRA_CEC_RX_TIMING_1, 212 (0x35 << TEGRA_CEC_RX_TIM1_DATA_BIT_MAX_LO_TIME_SHIFT) | 213 (0x21 << TEGRA_CEC_RX_TIM1_DATA_BIT_SAMPLE_TIME_SHIFT) | 214 (0x56 << TEGRA_CEC_RX_TIM1_DATA_BIT_MAX_DURATION_SHIFT) | 215 (0x40 << TEGRA_CEC_RX_TIM1_DATA_BIT_MIN_DURATION_SHIFT)); 216 217 cec_write(cec, TEGRA_CEC_RX_TIMING_2, 218 (0x50 << TEGRA_CEC_RX_TIM2_END_OF_BLOCK_TIME_SHIFT)); 219 220 cec_write(cec, TEGRA_CEC_TX_TIMING_0, 221 (0x74 << TEGRA_CEC_TX_TIM0_START_BIT_LO_TIME_SHIFT) | 222 (0x8d << TEGRA_CEC_TX_TIM0_START_BIT_DURATION_SHIFT) | 223 (0x08 << TEGRA_CEC_TX_TIM0_BUS_XITION_TIME_SHIFT) | 224 (0x71 << TEGRA_CEC_TX_TIM0_BUS_ERROR_LO_TIME_SHIFT)); 225 226 cec_write(cec, TEGRA_CEC_TX_TIMING_1, 227 (0x2f << TEGRA_CEC_TX_TIM1_LO_DATA_BIT_LO_TIME_SHIFT) | 228 (0x13 << TEGRA_CEC_TX_TIM1_HI_DATA_BIT_LO_TIME_SHIFT) | 229 (0x4b << TEGRA_CEC_TX_TIM1_DATA_BIT_DURATION_SHIFT) | 230 (0x21 << TEGRA_CEC_TX_TIM1_ACK_NAK_BIT_SAMPLE_TIME_SHIFT)); 231 232 cec_write(cec, TEGRA_CEC_TX_TIMING_2, 233 (0x07 << TEGRA_CEC_TX_TIM2_BUS_IDLE_TIME_ADDITIONAL_FRAME_SHIFT) | 234 (0x05 << TEGRA_CEC_TX_TIM2_BUS_IDLE_TIME_NEW_FRAME_SHIFT) | 235 (0x03 << TEGRA_CEC_TX_TIM2_BUS_IDLE_TIME_RETRY_FRAME_SHIFT)); 236 237 cec_write(cec, TEGRA_CEC_INT_MASK, 238 TEGRA_CEC_INT_MASK_TX_REGISTER_UNDERRUN | 239 TEGRA_CEC_INT_MASK_TX_FRAME_OR_BLOCK_NAKD | 240 TEGRA_CEC_INT_MASK_TX_ARBITRATION_FAILED | 241 TEGRA_CEC_INT_MASK_TX_BUS_ANOMALY_DETECTED | 242 TEGRA_CEC_INT_MASK_TX_FRAME_TRANSMITTED | 243 TEGRA_CEC_INT_MASK_RX_REGISTER_FULL | 244 TEGRA_CEC_INT_MASK_RX_START_BIT_DETECTED); 245 246 cec_write(cec, TEGRA_CEC_HW_CONTROL, TEGRA_CEC_HWCTRL_TX_RX_MODE); 247 return 0; 248 } 249 250 static int tegra_cec_adap_log_addr(struct cec_adapter *adap, u8 logical_addr) 251 { 252 struct tegra_cec *cec = adap->priv; 253 u32 state = cec_read(cec, TEGRA_CEC_HW_CONTROL); 254 255 if (logical_addr == CEC_LOG_ADDR_INVALID) 256 state &= ~TEGRA_CEC_HWCTRL_RX_LADDR_MASK; 257 else 258 state |= TEGRA_CEC_HWCTRL_RX_LADDR((1 << logical_addr)); 259 260 cec_write(cec, TEGRA_CEC_HW_CONTROL, state); 261 return 0; 262 } 263 264 static int tegra_cec_adap_monitor_all_enable(struct cec_adapter *adap, 265 bool enable) 266 { 267 struct tegra_cec *cec = adap->priv; 268 u32 reg = cec_read(cec, TEGRA_CEC_HW_CONTROL); 269 270 if (enable) 271 reg |= TEGRA_CEC_HWCTRL_RX_SNOOP; 272 else 273 reg &= ~TEGRA_CEC_HWCTRL_RX_SNOOP; 274 cec_write(cec, TEGRA_CEC_HW_CONTROL, reg); 275 return 0; 276 } 277 278 static int tegra_cec_adap_transmit(struct cec_adapter *adap, u8 attempts, 279 u32 signal_free_time_ms, struct cec_msg *msg) 280 { 281 bool retry_xfer = signal_free_time_ms == CEC_SIGNAL_FREE_TIME_RETRY; 282 struct tegra_cec *cec = adap->priv; 283 unsigned int i; 284 u32 mode = 0; 285 u32 mask; 286 287 if (cec_msg_is_broadcast(msg)) 288 mode = TEGRA_CEC_TX_REG_BCAST; 289 290 cec->tx_buf_cur = 0; 291 cec->tx_buf_cnt = msg->len; 292 293 for (i = 0; i < msg->len; i++) { 294 cec->tx_buf[i] = mode | msg->msg[i]; 295 if (i == 0) 296 cec->tx_buf[i] |= TEGRA_CEC_TX_REG_START_BIT; 297 if (i == msg->len - 1) 298 cec->tx_buf[i] |= TEGRA_CEC_TX_REG_EOM; 299 if (i == 0 && retry_xfer) 300 cec->tx_buf[i] |= TEGRA_CEC_TX_REG_RETRY; 301 } 302 303 mask = cec_read(cec, TEGRA_CEC_INT_MASK); 304 cec_write(cec, TEGRA_CEC_INT_MASK, 305 mask | TEGRA_CEC_INT_MASK_TX_REGISTER_EMPTY); 306 307 return 0; 308 } 309 310 static const struct cec_adap_ops tegra_cec_ops = { 311 .adap_enable = tegra_cec_adap_enable, 312 .adap_log_addr = tegra_cec_adap_log_addr, 313 .adap_transmit = tegra_cec_adap_transmit, 314 .adap_monitor_all_enable = tegra_cec_adap_monitor_all_enable, 315 }; 316 317 static int tegra_cec_probe(struct platform_device *pdev) 318 { 319 struct device *hdmi_dev; 320 struct tegra_cec *cec; 321 struct resource *res; 322 int ret = 0; 323 324 hdmi_dev = cec_notifier_parse_hdmi_phandle(&pdev->dev); 325 326 if (IS_ERR(hdmi_dev)) 327 return PTR_ERR(hdmi_dev); 328 329 cec = devm_kzalloc(&pdev->dev, sizeof(struct tegra_cec), GFP_KERNEL); 330 331 if (!cec) 332 return -ENOMEM; 333 334 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 335 336 if (!res) { 337 dev_err(&pdev->dev, 338 "Unable to allocate resources for device\n"); 339 return -EBUSY; 340 } 341 342 if (!devm_request_mem_region(&pdev->dev, res->start, resource_size(res), 343 pdev->name)) { 344 dev_err(&pdev->dev, 345 "Unable to request mem region for device\n"); 346 return -EBUSY; 347 } 348 349 cec->tegra_cec_irq = platform_get_irq(pdev, 0); 350 351 if (cec->tegra_cec_irq <= 0) 352 return -EBUSY; 353 354 cec->cec_base = devm_ioremap(&pdev->dev, res->start, 355 resource_size(res)); 356 357 if (!cec->cec_base) { 358 dev_err(&pdev->dev, "Unable to grab IOs for device\n"); 359 return -EBUSY; 360 } 361 362 cec->clk = devm_clk_get(&pdev->dev, "cec"); 363 364 if (IS_ERR_OR_NULL(cec->clk)) { 365 dev_err(&pdev->dev, "Can't get clock for CEC\n"); 366 return -ENOENT; 367 } 368 369 ret = clk_prepare_enable(cec->clk); 370 if (ret) { 371 dev_err(&pdev->dev, "Unable to prepare clock for CEC\n"); 372 return ret; 373 } 374 375 /* set context info. */ 376 cec->dev = &pdev->dev; 377 378 platform_set_drvdata(pdev, cec); 379 380 ret = devm_request_threaded_irq(&pdev->dev, cec->tegra_cec_irq, 381 tegra_cec_irq_handler, tegra_cec_irq_thread_handler, 382 0, "cec_irq", &pdev->dev); 383 384 if (ret) { 385 dev_err(&pdev->dev, 386 "Unable to request interrupt for device\n"); 387 goto err_clk; 388 } 389 390 cec->adap = cec_allocate_adapter(&tegra_cec_ops, cec, TEGRA_CEC_NAME, 391 CEC_CAP_DEFAULTS | CEC_CAP_MONITOR_ALL | 392 CEC_CAP_CONNECTOR_INFO, 393 CEC_MAX_LOG_ADDRS); 394 if (IS_ERR(cec->adap)) { 395 ret = -ENOMEM; 396 dev_err(&pdev->dev, "Couldn't create cec adapter\n"); 397 goto err_clk; 398 } 399 400 cec->notifier = cec_notifier_cec_adap_register(hdmi_dev, NULL, 401 cec->adap); 402 if (!cec->notifier) { 403 ret = -ENOMEM; 404 goto err_adapter; 405 } 406 407 ret = cec_register_adapter(cec->adap, &pdev->dev); 408 if (ret) { 409 dev_err(&pdev->dev, "Couldn't register device\n"); 410 goto err_notifier; 411 } 412 413 return 0; 414 415 err_notifier: 416 cec_notifier_cec_adap_unregister(cec->notifier, cec->adap); 417 err_adapter: 418 cec_delete_adapter(cec->adap); 419 err_clk: 420 clk_disable_unprepare(cec->clk); 421 return ret; 422 } 423 424 static int tegra_cec_remove(struct platform_device *pdev) 425 { 426 struct tegra_cec *cec = platform_get_drvdata(pdev); 427 428 clk_disable_unprepare(cec->clk); 429 430 cec_notifier_cec_adap_unregister(cec->notifier, cec->adap); 431 cec_unregister_adapter(cec->adap); 432 433 return 0; 434 } 435 436 #ifdef CONFIG_PM 437 static int tegra_cec_suspend(struct platform_device *pdev, pm_message_t state) 438 { 439 struct tegra_cec *cec = platform_get_drvdata(pdev); 440 441 clk_disable_unprepare(cec->clk); 442 443 dev_notice(&pdev->dev, "suspended\n"); 444 return 0; 445 } 446 447 static int tegra_cec_resume(struct platform_device *pdev) 448 { 449 struct tegra_cec *cec = platform_get_drvdata(pdev); 450 451 dev_notice(&pdev->dev, "Resuming\n"); 452 453 return clk_prepare_enable(cec->clk); 454 } 455 #endif 456 457 static const struct of_device_id tegra_cec_of_match[] = { 458 { .compatible = "nvidia,tegra114-cec", }, 459 { .compatible = "nvidia,tegra124-cec", }, 460 { .compatible = "nvidia,tegra210-cec", }, 461 {}, 462 }; 463 464 static struct platform_driver tegra_cec_driver = { 465 .driver = { 466 .name = TEGRA_CEC_NAME, 467 .of_match_table = of_match_ptr(tegra_cec_of_match), 468 }, 469 .probe = tegra_cec_probe, 470 .remove = tegra_cec_remove, 471 472 #ifdef CONFIG_PM 473 .suspend = tegra_cec_suspend, 474 .resume = tegra_cec_resume, 475 #endif 476 }; 477 478 module_platform_driver(tegra_cec_driver); 479 480 MODULE_DESCRIPTION("Tegra HDMI CEC driver"); 481 MODULE_AUTHOR("NVIDIA CORPORATION"); 482 MODULE_AUTHOR("Cisco Systems, Inc. and/or its affiliates"); 483 MODULE_LICENSE("GPL v2"); 484