1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2015 VanguardiaSur - www.vanguardiasur.com.ar 4 * 5 * Based on original driver by Krzysztof Ha?asa: 6 * Copyright (C) 2015 Industrial Research Institute for Automation 7 * and Measurements PIAP 8 * 9 * Notes 10 * ----- 11 * 12 * 1. Under stress-testing, it has been observed that the PCIe link 13 * goes down, without reason. Therefore, the driver takes special care 14 * to allow device hot-unplugging. 15 * 16 * 2. TW686X devices are capable of setting a few different DMA modes, 17 * including: scatter-gather, field and frame modes. However, 18 * under stress testings it has been found that the machine can 19 * freeze completely if DMA registers are programmed while streaming 20 * is active. 21 * 22 * Therefore, driver implements a dma_mode called 'memcpy' which 23 * avoids cycling the DMA buffers, and insteads allocates extra DMA buffers 24 * and then copies into vmalloc'ed user buffers. 25 * 26 * In addition to this, when streaming is on, the driver tries to access 27 * hardware registers as infrequently as possible. This is done by using 28 * a timer to limit the rate at which DMA is reset on DMA channels error. 29 */ 30 31 #include <linux/init.h> 32 #include <linux/interrupt.h> 33 #include <linux/delay.h> 34 #include <linux/kernel.h> 35 #include <linux/module.h> 36 #include <linux/pci_ids.h> 37 #include <linux/slab.h> 38 #include <linux/timer.h> 39 40 #include "tw686x.h" 41 #include "tw686x-regs.h" 42 43 /* 44 * This module parameter allows to control the DMA_TIMER_INTERVAL value. 45 * The DMA_TIMER_INTERVAL register controls the minimum DMA interrupt 46 * time span (iow, the maximum DMA interrupt rate) thus allowing for 47 * IRQ coalescing. 48 * 49 * The chip datasheet does not mention a time unit for this value, so 50 * users wanting fine-grain control over the interrupt rate should 51 * determine the desired value through testing. 52 */ 53 static u32 dma_interval = 0x00098968; 54 module_param(dma_interval, int, 0444); 55 MODULE_PARM_DESC(dma_interval, "Minimum time span for DMA interrupting host"); 56 57 static unsigned int dma_mode = TW686X_DMA_MODE_MEMCPY; 58 static const char *dma_mode_name(unsigned int mode) 59 { 60 switch (mode) { 61 case TW686X_DMA_MODE_MEMCPY: 62 return "memcpy"; 63 case TW686X_DMA_MODE_CONTIG: 64 return "contig"; 65 case TW686X_DMA_MODE_SG: 66 return "sg"; 67 default: 68 return "unknown"; 69 } 70 } 71 72 static int tw686x_dma_mode_get(char *buffer, const struct kernel_param *kp) 73 { 74 return sprintf(buffer, "%s", dma_mode_name(dma_mode)); 75 } 76 77 static int tw686x_dma_mode_set(const char *val, const struct kernel_param *kp) 78 { 79 if (!strcasecmp(val, dma_mode_name(TW686X_DMA_MODE_MEMCPY))) 80 dma_mode = TW686X_DMA_MODE_MEMCPY; 81 else if (!strcasecmp(val, dma_mode_name(TW686X_DMA_MODE_CONTIG))) 82 dma_mode = TW686X_DMA_MODE_CONTIG; 83 else if (!strcasecmp(val, dma_mode_name(TW686X_DMA_MODE_SG))) 84 dma_mode = TW686X_DMA_MODE_SG; 85 else 86 return -EINVAL; 87 return 0; 88 } 89 module_param_call(dma_mode, tw686x_dma_mode_set, tw686x_dma_mode_get, 90 &dma_mode, S_IRUGO|S_IWUSR); 91 MODULE_PARM_DESC(dma_mode, "DMA operation mode (memcpy/contig/sg, default=memcpy)"); 92 93 void tw686x_disable_channel(struct tw686x_dev *dev, unsigned int channel) 94 { 95 u32 dma_en = reg_read(dev, DMA_CHANNEL_ENABLE); 96 u32 dma_cmd = reg_read(dev, DMA_CMD); 97 98 dma_en &= ~BIT(channel); 99 dma_cmd &= ~BIT(channel); 100 101 /* Must remove it from pending too */ 102 dev->pending_dma_en &= ~BIT(channel); 103 dev->pending_dma_cmd &= ~BIT(channel); 104 105 /* Stop DMA if no channels are enabled */ 106 if (!dma_en) 107 dma_cmd = 0; 108 reg_write(dev, DMA_CHANNEL_ENABLE, dma_en); 109 reg_write(dev, DMA_CMD, dma_cmd); 110 } 111 112 void tw686x_enable_channel(struct tw686x_dev *dev, unsigned int channel) 113 { 114 u32 dma_en = reg_read(dev, DMA_CHANNEL_ENABLE); 115 u32 dma_cmd = reg_read(dev, DMA_CMD); 116 117 dev->pending_dma_en |= dma_en | BIT(channel); 118 dev->pending_dma_cmd |= dma_cmd | DMA_CMD_ENABLE | BIT(channel); 119 } 120 121 /* 122 * The purpose of this awful hack is to avoid enabling the DMA 123 * channels "too fast" which makes some TW686x devices very 124 * angry and freeze the CPU (see note 1). 125 */ 126 static void tw686x_dma_delay(struct timer_list *t) 127 { 128 struct tw686x_dev *dev = from_timer(dev, t, dma_delay_timer); 129 unsigned long flags; 130 131 spin_lock_irqsave(&dev->lock, flags); 132 133 reg_write(dev, DMA_CHANNEL_ENABLE, dev->pending_dma_en); 134 reg_write(dev, DMA_CMD, dev->pending_dma_cmd); 135 dev->pending_dma_en = 0; 136 dev->pending_dma_cmd = 0; 137 138 spin_unlock_irqrestore(&dev->lock, flags); 139 } 140 141 static void tw686x_reset_channels(struct tw686x_dev *dev, unsigned int ch_mask) 142 { 143 u32 dma_en, dma_cmd; 144 145 dma_en = reg_read(dev, DMA_CHANNEL_ENABLE); 146 dma_cmd = reg_read(dev, DMA_CMD); 147 148 /* 149 * Save pending register status, the timer will 150 * restore them. 151 */ 152 dev->pending_dma_en |= dma_en; 153 dev->pending_dma_cmd |= dma_cmd; 154 155 /* Disable the reset channels */ 156 reg_write(dev, DMA_CHANNEL_ENABLE, dma_en & ~ch_mask); 157 158 if ((dma_en & ~ch_mask) == 0) { 159 dev_dbg(&dev->pci_dev->dev, "reset: stopping DMA\n"); 160 dma_cmd &= ~DMA_CMD_ENABLE; 161 } 162 reg_write(dev, DMA_CMD, dma_cmd & ~ch_mask); 163 } 164 165 static irqreturn_t tw686x_irq(int irq, void *dev_id) 166 { 167 struct tw686x_dev *dev = (struct tw686x_dev *)dev_id; 168 unsigned int video_requests, audio_requests, reset_ch; 169 u32 fifo_status, fifo_signal, fifo_ov, fifo_bad, fifo_errors; 170 u32 int_status, dma_en, video_en, pb_status; 171 unsigned long flags; 172 173 int_status = reg_read(dev, INT_STATUS); /* cleared on read */ 174 fifo_status = reg_read(dev, VIDEO_FIFO_STATUS); 175 176 /* INT_STATUS does not include FIFO_STATUS errors! */ 177 if (!int_status && !TW686X_FIFO_ERROR(fifo_status)) 178 return IRQ_NONE; 179 180 if (int_status & INT_STATUS_DMA_TOUT) { 181 dev_dbg(&dev->pci_dev->dev, 182 "DMA timeout. Resetting DMA for all channels\n"); 183 reset_ch = ~0; 184 goto reset_channels; 185 } 186 187 spin_lock_irqsave(&dev->lock, flags); 188 dma_en = reg_read(dev, DMA_CHANNEL_ENABLE); 189 spin_unlock_irqrestore(&dev->lock, flags); 190 191 video_en = dma_en & 0xff; 192 fifo_signal = ~(fifo_status & 0xff) & video_en; 193 fifo_ov = fifo_status >> 24; 194 fifo_bad = fifo_status >> 16; 195 196 /* Mask of channels with signal and FIFO errors */ 197 fifo_errors = fifo_signal & (fifo_ov | fifo_bad); 198 199 reset_ch = 0; 200 pb_status = reg_read(dev, PB_STATUS); 201 202 /* Coalesce video frame/error events */ 203 video_requests = (int_status & video_en) | fifo_errors; 204 audio_requests = (int_status & dma_en) >> 8; 205 206 if (video_requests) 207 tw686x_video_irq(dev, video_requests, pb_status, 208 fifo_status, &reset_ch); 209 if (audio_requests) 210 tw686x_audio_irq(dev, audio_requests, pb_status); 211 212 reset_channels: 213 if (reset_ch) { 214 spin_lock_irqsave(&dev->lock, flags); 215 tw686x_reset_channels(dev, reset_ch); 216 spin_unlock_irqrestore(&dev->lock, flags); 217 mod_timer(&dev->dma_delay_timer, 218 jiffies + msecs_to_jiffies(100)); 219 } 220 221 return IRQ_HANDLED; 222 } 223 224 static void tw686x_dev_release(struct v4l2_device *v4l2_dev) 225 { 226 struct tw686x_dev *dev = container_of(v4l2_dev, struct tw686x_dev, 227 v4l2_dev); 228 unsigned int ch; 229 230 for (ch = 0; ch < max_channels(dev); ch++) 231 v4l2_ctrl_handler_free(&dev->video_channels[ch].ctrl_handler); 232 233 v4l2_device_unregister(&dev->v4l2_dev); 234 235 kfree(dev->audio_channels); 236 kfree(dev->video_channels); 237 kfree(dev); 238 } 239 240 static int tw686x_probe(struct pci_dev *pci_dev, 241 const struct pci_device_id *pci_id) 242 { 243 struct tw686x_dev *dev; 244 int err; 245 246 dev = kzalloc(sizeof(*dev), GFP_KERNEL); 247 if (!dev) 248 return -ENOMEM; 249 dev->type = pci_id->driver_data; 250 dev->dma_mode = dma_mode; 251 sprintf(dev->name, "tw%04X", pci_dev->device); 252 253 dev->video_channels = kcalloc(max_channels(dev), 254 sizeof(*dev->video_channels), GFP_KERNEL); 255 if (!dev->video_channels) { 256 err = -ENOMEM; 257 goto free_dev; 258 } 259 260 dev->audio_channels = kcalloc(max_channels(dev), 261 sizeof(*dev->audio_channels), GFP_KERNEL); 262 if (!dev->audio_channels) { 263 err = -ENOMEM; 264 goto free_video; 265 } 266 267 pr_info("%s: PCI %s, IRQ %d, MMIO 0x%lx (%s mode)\n", dev->name, 268 pci_name(pci_dev), pci_dev->irq, 269 (unsigned long)pci_resource_start(pci_dev, 0), 270 dma_mode_name(dma_mode)); 271 272 dev->pci_dev = pci_dev; 273 if (pci_enable_device(pci_dev)) { 274 err = -EIO; 275 goto free_audio; 276 } 277 278 pci_set_master(pci_dev); 279 err = dma_set_mask(&pci_dev->dev, DMA_BIT_MASK(32)); 280 if (err) { 281 dev_err(&pci_dev->dev, "32-bit PCI DMA not supported\n"); 282 err = -EIO; 283 goto disable_pci; 284 } 285 286 err = pci_request_regions(pci_dev, dev->name); 287 if (err) { 288 dev_err(&pci_dev->dev, "unable to request PCI region\n"); 289 goto disable_pci; 290 } 291 292 dev->mmio = pci_ioremap_bar(pci_dev, 0); 293 if (!dev->mmio) { 294 dev_err(&pci_dev->dev, "unable to remap PCI region\n"); 295 err = -ENOMEM; 296 goto free_region; 297 } 298 299 /* Reset all subsystems */ 300 reg_write(dev, SYS_SOFT_RST, 0x0f); 301 mdelay(1); 302 303 reg_write(dev, SRST[0], 0x3f); 304 if (max_channels(dev) > 4) 305 reg_write(dev, SRST[1], 0x3f); 306 307 /* Disable the DMA engine */ 308 reg_write(dev, DMA_CMD, 0); 309 reg_write(dev, DMA_CHANNEL_ENABLE, 0); 310 311 /* Enable DMA FIFO overflow and pointer check */ 312 reg_write(dev, DMA_CONFIG, 0xffffff04); 313 reg_write(dev, DMA_CHANNEL_TIMEOUT, 0x140c8584); 314 reg_write(dev, DMA_TIMER_INTERVAL, dma_interval); 315 316 spin_lock_init(&dev->lock); 317 318 err = request_irq(pci_dev->irq, tw686x_irq, IRQF_SHARED, 319 dev->name, dev); 320 if (err < 0) { 321 dev_err(&pci_dev->dev, "unable to request interrupt\n"); 322 goto iounmap; 323 } 324 325 timer_setup(&dev->dma_delay_timer, tw686x_dma_delay, 0); 326 327 /* 328 * This must be set right before initializing v4l2_dev. 329 * It's used to release resources after the last handle 330 * held is released. 331 */ 332 dev->v4l2_dev.release = tw686x_dev_release; 333 err = tw686x_video_init(dev); 334 if (err) { 335 dev_err(&pci_dev->dev, "can't register video\n"); 336 goto free_irq; 337 } 338 339 err = tw686x_audio_init(dev); 340 if (err) 341 dev_warn(&pci_dev->dev, "can't register audio\n"); 342 343 pci_set_drvdata(pci_dev, dev); 344 return 0; 345 346 free_irq: 347 free_irq(pci_dev->irq, dev); 348 iounmap: 349 pci_iounmap(pci_dev, dev->mmio); 350 free_region: 351 pci_release_regions(pci_dev); 352 disable_pci: 353 pci_disable_device(pci_dev); 354 free_audio: 355 kfree(dev->audio_channels); 356 free_video: 357 kfree(dev->video_channels); 358 free_dev: 359 kfree(dev); 360 return err; 361 } 362 363 static void tw686x_remove(struct pci_dev *pci_dev) 364 { 365 struct tw686x_dev *dev = pci_get_drvdata(pci_dev); 366 unsigned long flags; 367 368 /* This guarantees the IRQ handler is no longer running, 369 * which means we can kiss good-bye some resources. 370 */ 371 free_irq(pci_dev->irq, dev); 372 373 tw686x_video_free(dev); 374 tw686x_audio_free(dev); 375 del_timer_sync(&dev->dma_delay_timer); 376 377 pci_iounmap(pci_dev, dev->mmio); 378 pci_release_regions(pci_dev); 379 pci_disable_device(pci_dev); 380 381 /* 382 * Setting pci_dev to NULL allows to detect hardware is no longer 383 * available and will be used by vb2_ops. This is required because 384 * the device sometimes hot-unplugs itself as the result of a PCIe 385 * link down. 386 * The lock is really important here. 387 */ 388 spin_lock_irqsave(&dev->lock, flags); 389 dev->pci_dev = NULL; 390 spin_unlock_irqrestore(&dev->lock, flags); 391 392 /* 393 * This calls tw686x_dev_release if it's the last reference. 394 * Otherwise, release is postponed until there are no users left. 395 */ 396 v4l2_device_put(&dev->v4l2_dev); 397 } 398 399 /* 400 * On TW6864 and TW6868, all channels share the pair of video DMA SG tables, 401 * with 10-bit start_idx and end_idx determining start and end of frame buffer 402 * for particular channel. 403 * TW6868 with all its 8 channels would be problematic (only 127 SG entries per 404 * channel) but we support only 4 channels on this chip anyway (the first 405 * 4 channels are driven with internal video decoder, the other 4 would require 406 * an external TW286x part). 407 * 408 * On TW6865 and TW6869, each channel has its own DMA SG table, with indexes 409 * starting with 0. Both chips have complete sets of internal video decoders 410 * (respectively 4 or 8-channel). 411 * 412 * All chips have separate SG tables for two video frames. 413 */ 414 415 /* driver_data is number of A/V channels */ 416 static const struct pci_device_id tw686x_pci_tbl[] = { 417 { 418 PCI_DEVICE(PCI_VENDOR_ID_TECHWELL, 0x6864), 419 .driver_data = 4 420 }, 421 { 422 PCI_DEVICE(PCI_VENDOR_ID_TECHWELL, 0x6865), /* not tested */ 423 .driver_data = 4 | TYPE_SECOND_GEN 424 }, 425 /* 426 * TW6868 supports 8 A/V channels with an external TW2865 chip; 427 * not supported by the driver. 428 */ 429 { 430 PCI_DEVICE(PCI_VENDOR_ID_TECHWELL, 0x6868), /* not tested */ 431 .driver_data = 4 432 }, 433 { 434 PCI_DEVICE(PCI_VENDOR_ID_TECHWELL, 0x6869), 435 .driver_data = 8 | TYPE_SECOND_GEN}, 436 {} 437 }; 438 MODULE_DEVICE_TABLE(pci, tw686x_pci_tbl); 439 440 static struct pci_driver tw686x_pci_driver = { 441 .name = "tw686x", 442 .id_table = tw686x_pci_tbl, 443 .probe = tw686x_probe, 444 .remove = tw686x_remove, 445 }; 446 module_pci_driver(tw686x_pci_driver); 447 448 MODULE_DESCRIPTION("Driver for video frame grabber cards based on Intersil/Techwell TW686[4589]"); 449 MODULE_AUTHOR("Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>"); 450 MODULE_AUTHOR("Krzysztof Ha?asa <khalasa@piap.pl>"); 451 MODULE_LICENSE("GPL v2"); 452