drivers/staging/axis-fifo/axis-fifo.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Xilinx AXIS FIFO: interface to the Xilinx AXI-Stream FIFO IP core
   4  *
   5  * Copyright (C) 2018 Jacob Feder
   6  *
   7  * Authors:  Jacob Feder <jacobsfeder@gmail.com>
   8  *
   9  * See Xilinx PG080 document for IP details
  10  */
  11
  12 /* ----------------------------
  13  *           includes
  14  * ----------------------------
  15  */
  16
  17 #include <linux/kernel.h>
  18 #include <linux/wait.h>
  19 #include <linux/spinlock_types.h>
  20 #include <linux/device.h>
  21 #include <linux/cdev.h>
  22 #include <linux/init.h>
  23 #include <linux/module.h>
  24 #include <linux/slab.h>
  25 #include <linux/io.h>
  26 #include <linux/moduleparam.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/param.h>
  29 #include <linux/fs.h>
  30 #include <linux/types.h>
  31 #include <linux/uaccess.h>
  32 #include <linux/jiffies.h>
  33
  34 #include <linux/of_address.h>
  35 #include <linux/of_device.h>
  36 #include <linux/of_platform.h>
  37
  38 /* ----------------------------
  39  *       driver parameters
  40  * ----------------------------
  41  */
  42
  43 #define DRIVER_NAME "axis_fifo"
  44
  45 #define READ_BUF_SIZE 128U /* read buffer length in words */
  46 #define WRITE_BUF_SIZE 128U /* write buffer length in words */
  47
  48 /* ----------------------------
  49  *     IP register offsets
  50  * ----------------------------
  51  */
  52
  53 #define XLLF_ISR_OFFSET  0x00000000  /* Interrupt Status */
  54 #define XLLF_IER_OFFSET  0x00000004  /* Interrupt Enable */
  55
  56 #define XLLF_TDFR_OFFSET 0x00000008  /* Transmit Reset */
  57 #define XLLF_TDFV_OFFSET 0x0000000c  /* Transmit Vacancy */
  58 #define XLLF_TDFD_OFFSET 0x00000010  /* Transmit Data */
  59 #define XLLF_TLR_OFFSET  0x00000014  /* Transmit Length */
  60
  61 #define XLLF_RDFR_OFFSET 0x00000018  /* Receive Reset */
  62 #define XLLF_RDFO_OFFSET 0x0000001c  /* Receive Occupancy */
  63 #define XLLF_RDFD_OFFSET 0x00000020  /* Receive Data */
  64 #define XLLF_RLR_OFFSET  0x00000024  /* Receive Length */
  65 #define XLLF_SRR_OFFSET  0x00000028  /* Local Link Reset */
  66 #define XLLF_TDR_OFFSET  0x0000002C  /* Transmit Destination */
  67 #define XLLF_RDR_OFFSET  0x00000030  /* Receive Destination */
  68
  69 /* ----------------------------
  70  *     reset register masks
  71  * ----------------------------
  72  */
  73
  74 #define XLLF_RDFR_RESET_MASK        0x000000a5 /* receive reset value */
  75 #define XLLF_TDFR_RESET_MASK        0x000000a5 /* Transmit reset value */
  76 #define XLLF_SRR_RESET_MASK         0x000000a5 /* Local Link reset value */
  77
  78 /* ----------------------------
  79  *       interrupt masks
  80  * ----------------------------
  81  */
  82
  83 #define XLLF_INT_RPURE_MASK       0x80000000 /* Receive under-read */
  84 #define XLLF_INT_RPORE_MASK       0x40000000 /* Receive over-read */
  85 #define XLLF_INT_RPUE_MASK        0x20000000 /* Receive underrun (empty) */
  86 #define XLLF_INT_TPOE_MASK        0x10000000 /* Transmit overrun */
  87 #define XLLF_INT_TC_MASK          0x08000000 /* Transmit complete */
  88 #define XLLF_INT_RC_MASK          0x04000000 /* Receive complete */
  89 #define XLLF_INT_TSE_MASK         0x02000000 /* Transmit length mismatch */
  90 #define XLLF_INT_TRC_MASK         0x01000000 /* Transmit reset complete */
  91 #define XLLF_INT_RRC_MASK         0x00800000 /* Receive reset complete */
  92 #define XLLF_INT_TFPF_MASK        0x00400000 /* Tx FIFO Programmable Full */
  93 #define XLLF_INT_TFPE_MASK        0x00200000 /* Tx FIFO Programmable Empty */
  94 #define XLLF_INT_RFPF_MASK        0x00100000 /* Rx FIFO Programmable Full */
  95 #define XLLF_INT_RFPE_MASK        0x00080000 /* Rx FIFO Programmable Empty */
  96 #define XLLF_INT_ALL_MASK         0xfff80000 /* All the ints */
  97 #define XLLF_INT_ERROR_MASK       0xf2000000 /* Error status ints */
  98 #define XLLF_INT_RXERROR_MASK     0xe0000000 /* Receive Error status ints */
  99 #define XLLF_INT_TXERROR_MASK     0x12000000 /* Transmit Error status ints */
 100
 101 /* ----------------------------
 102  *           globals
 103  * ----------------------------
 104  */
 105
 106 static struct class *axis_fifo_driver_class; /* char device class */
 107
 108 static int read_timeout = 1000; /* ms to wait before read() times out */
 109 static int write_timeout = 1000; /* ms to wait before write() times out */
 110
 111 /* ----------------------------
 112  * module command-line arguments
 113  * ----------------------------
 114  */
 115
 116 module_param(read_timeout, int, 0444);
 117 MODULE_PARM_DESC(read_timeout, "ms to wait before blocking read() timing out; set to -1 for no timeout");
 118 module_param(write_timeout, int, 0444);
 119 MODULE_PARM_DESC(write_timeout, "ms to wait before blocking write() timing out; set to -1 for no timeout");
 120
 121 /* ----------------------------
 122  *            types
 123  * ----------------------------
 124  */
 125
 126 struct axis_fifo {
 127         int irq; /* interrupt */
 128         struct resource *mem; /* physical memory */
 129         void __iomem *base_addr; /* kernel space memory */
 130
 131         unsigned int rx_fifo_depth; /* max words in the receive fifo */
 132         unsigned int tx_fifo_depth; /* max words in the transmit fifo */
 133         int has_rx_fifo; /* whether the IP has the rx fifo enabled */
 134         int has_tx_fifo; /* whether the IP has the tx fifo enabled */
 135
 136         wait_queue_head_t read_queue; /* wait queue for asynchronos read */
 137         spinlock_t read_queue_lock; /* lock for reading waitqueue */
 138         wait_queue_head_t write_queue; /* wait queue for asynchronos write */
 139         spinlock_t write_queue_lock; /* lock for writing waitqueue */
 140         unsigned int write_flags; /* write file flags */
 141         unsigned int read_flags; /* read file flags */
 142
 143         struct device *dt_device; /* device created from the device tree */
 144         struct device *device; /* device associated with char_device */
 145         dev_t devt; /* our char device number */
 146         struct cdev char_device; /* our char device */
 147 };
 148
 149 /* ----------------------------
 150  *         sysfs entries
 151  * ----------------------------
 152  */
 153
 154 static ssize_t sysfs_write(struct device *dev, const char *buf,
 155                            size_t count, unsigned int addr_offset)
 156 {
 157         struct axis_fifo *fifo = dev_get_drvdata(dev);
 158         unsigned long tmp;
 159         int rc;
 160
 161         rc = kstrtoul(buf, 0, &tmp);
 162         if (rc < 0)
 163                 return rc;
 164
 165         iowrite32(tmp, fifo->base_addr + addr_offset);
 166
 167         return count;
 168 }
 169
 170 static ssize_t sysfs_read(struct device *dev, char *buf,
 171                           unsigned int addr_offset)
 172 {
 173         struct axis_fifo *fifo = dev_get_drvdata(dev);
 174         unsigned int read_val;
 175         unsigned int len;
 176         char tmp[32];
 177
 178         read_val = ioread32(fifo->base_addr + addr_offset);
 179         len =  snprintf(tmp, sizeof(tmp), "0x%x\n", read_val);
 180         memcpy(buf, tmp, len);
 181
 182         return len;
 183 }
 184
 185 static ssize_t isr_store(struct device *dev, struct device_attribute *attr,
 186                          const char *buf, size_t count)
 187 {
 188         return sysfs_write(dev, buf, count, XLLF_ISR_OFFSET);
 189 }
 190
 191 static ssize_t isr_show(struct device *dev,
 192                         struct device_attribute *attr, char *buf)
 193 {
 194         return sysfs_read(dev, buf, XLLF_ISR_OFFSET);
 195 }
 196
 197 static DEVICE_ATTR_RW(isr);
 198
 199 static ssize_t ier_store(struct device *dev, struct device_attribute *attr,
 200                          const char *buf, size_t count)
 201 {
 202         return sysfs_write(dev, buf, count, XLLF_IER_OFFSET);
 203 }
 204
 205 static ssize_t ier_show(struct device *dev,
 206                         struct device_attribute *attr, char *buf)
 207 {
 208         return sysfs_read(dev, buf, XLLF_IER_OFFSET);
 209 }
 210
 211 static DEVICE_ATTR_RW(ier);
 212
 213 static ssize_t tdfr_store(struct device *dev, struct device_attribute *attr,
 214                           const char *buf, size_t count)
 215 {
 216         return sysfs_write(dev, buf, count, XLLF_TDFR_OFFSET);
 217 }
 218
 219 static DEVICE_ATTR_WO(tdfr);
 220
 221 static ssize_t tdfv_show(struct device *dev,
 222                          struct device_attribute *attr, char *buf)
 223 {
 224         return sysfs_read(dev, buf, XLLF_TDFV_OFFSET);
 225 }
 226
 227 static DEVICE_ATTR_RO(tdfv);
 228
 229 static ssize_t tdfd_store(struct device *dev, struct device_attribute *attr,
 230                           const char *buf, size_t count)
 231 {
 232         return sysfs_write(dev, buf, count, XLLF_TDFD_OFFSET);
 233 }
 234
 235 static DEVICE_ATTR_WO(tdfd);
 236
 237 static ssize_t tlr_store(struct device *dev, struct device_attribute *attr,
 238                          const char *buf, size_t count)
 239 {
 240         return sysfs_write(dev, buf, count, XLLF_TLR_OFFSET);
 241 }
 242
 243 static DEVICE_ATTR_WO(tlr);
 244
 245 static ssize_t rdfr_store(struct device *dev, struct device_attribute *attr,
 246                           const char *buf, size_t count)
 247 {
 248         return sysfs_write(dev, buf, count, XLLF_RDFR_OFFSET);
 249 }
 250
 251 static DEVICE_ATTR_WO(rdfr);
 252
 253 static ssize_t rdfo_show(struct device *dev,
 254                          struct device_attribute *attr, char *buf)
 255 {
 256         return sysfs_read(dev, buf, XLLF_RDFO_OFFSET);
 257 }
 258
 259 static DEVICE_ATTR_RO(rdfo);
 260
 261 static ssize_t rdfd_show(struct device *dev,
 262                          struct device_attribute *attr, char *buf)
 263 {
 264         return sysfs_read(dev, buf, XLLF_RDFD_OFFSET);
 265 }
 266
 267 static DEVICE_ATTR_RO(rdfd);
 268
 269 static ssize_t rlr_show(struct device *dev,
 270                         struct device_attribute *attr, char *buf)
 271 {
 272         return sysfs_read(dev, buf, XLLF_RLR_OFFSET);
 273 }
 274
 275 static DEVICE_ATTR_RO(rlr);
 276
 277 static ssize_t srr_store(struct device *dev, struct device_attribute *attr,
 278                          const char *buf, size_t count)
 279 {
 280         return sysfs_write(dev, buf, count, XLLF_SRR_OFFSET);
 281 }
 282
 283 static DEVICE_ATTR_WO(srr);
 284
 285 static ssize_t tdr_store(struct device *dev, struct device_attribute *attr,
 286                          const char *buf, size_t count)
 287 {
 288         return sysfs_write(dev, buf, count, XLLF_TDR_OFFSET);
 289 }
 290
 291 static DEVICE_ATTR_WO(tdr);
 292
 293 static ssize_t rdr_show(struct device *dev,
 294                         struct device_attribute *attr, char *buf)
 295 {
 296         return sysfs_read(dev, buf, XLLF_RDR_OFFSET);
 297 }
 298
 299 static DEVICE_ATTR_RO(rdr);
 300
 301 static struct attribute *axis_fifo_attrs[] = {
 302         &dev_attr_isr.attr,
 303         &dev_attr_ier.attr,
 304         &dev_attr_tdfr.attr,
 305         &dev_attr_tdfv.attr,
 306         &dev_attr_tdfd.attr,
 307         &dev_attr_tlr.attr,
 308         &dev_attr_rdfr.attr,
 309         &dev_attr_rdfo.attr,
 310         &dev_attr_rdfd.attr,
 311         &dev_attr_rlr.attr,
 312         &dev_attr_srr.attr,
 313         &dev_attr_tdr.attr,
 314         &dev_attr_rdr.attr,
 315         NULL,
 316 };
 317
 318 static const struct attribute_group axis_fifo_attrs_group = {
 319         .name = "ip_registers",
 320         .attrs = axis_fifo_attrs,
 321 };
 322
 323 /* ----------------------------
 324  *        implementation
 325  * ----------------------------
 326  */
 327
 328 static void reset_ip_core(struct axis_fifo *fifo)
 329 {
 330         iowrite32(XLLF_SRR_RESET_MASK, fifo->base_addr + XLLF_SRR_OFFSET);
 331         iowrite32(XLLF_TDFR_RESET_MASK, fifo->base_addr + XLLF_TDFR_OFFSET);
 332         iowrite32(XLLF_RDFR_RESET_MASK, fifo->base_addr + XLLF_RDFR_OFFSET);
 333         iowrite32(XLLF_INT_TC_MASK | XLLF_INT_RC_MASK | XLLF_INT_RPURE_MASK |
 334                   XLLF_INT_RPORE_MASK | XLLF_INT_RPUE_MASK |
 335                   XLLF_INT_TPOE_MASK | XLLF_INT_TSE_MASK,
 336                   fifo->base_addr + XLLF_IER_OFFSET);
 337         iowrite32(XLLF_INT_ALL_MASK, fifo->base_addr + XLLF_ISR_OFFSET);
 338 }
 339
 340 /* reads a single packet from the fifo as dictated by the tlast signal */
 341 static ssize_t axis_fifo_read(struct file *f, char __user *buf,
 342                               size_t len, loff_t *off)
 343 {
 344         struct axis_fifo *fifo = (struct axis_fifo *)f->private_data;
 345         size_t bytes_available;
 346         unsigned int words_available;
 347         unsigned int copied;
 348         unsigned int copy;
 349         unsigned int i;
 350         int ret;
 351         u32 tmp_buf[READ_BUF_SIZE];
 352
 353         if (fifo->read_flags & O_NONBLOCK) {
 354                 /* opened in non-blocking mode
 355                  * return if there are no packets available
 356                  */
 357                 if (!ioread32(fifo->base_addr + XLLF_RDFO_OFFSET))
 358                         return -EAGAIN;
 359         } else {
 360                 /* opened in blocking mode
 361                  * wait for a packet available interrupt (or timeout)
 362                  * if nothing is currently available
 363                  */
 364                 spin_lock_irq(&fifo->read_queue_lock);
 365                 ret = wait_event_interruptible_lock_irq_timeout
 366                         (fifo->read_queue,
 367                          ioread32(fifo->base_addr + XLLF_RDFO_OFFSET),
 368                          fifo->read_queue_lock,
 369                          (read_timeout >= 0) ? msecs_to_jiffies(read_timeout) :
 370                                 MAX_SCHEDULE_TIMEOUT);
 371                 spin_unlock_irq(&fifo->read_queue_lock);
 372
 373                 if (ret == 0) {
 374                         /* timeout occurred */
 375                         dev_dbg(fifo->dt_device, "read timeout");
 376                         return -EAGAIN;
 377                 } else if (ret == -ERESTARTSYS) {
 378                         /* signal received */
 379                         return -ERESTARTSYS;
 380                 } else if (ret < 0) {
 381                         dev_err(fifo->dt_device, "wait_event_interruptible_timeout() error in read (ret=%i)\n",
 382                                 ret);
 383                         return ret;
 384                 }
 385         }
 386
 387         bytes_available = ioread32(fifo->base_addr + XLLF_RLR_OFFSET);
 388         if (!bytes_available) {
 389                 dev_err(fifo->dt_device, "received a packet of length 0 - fifo core will be reset\n");
 390                 reset_ip_core(fifo);
 391                 return -EIO;
 392         }
 393
 394         if (bytes_available > len) {
 395                 dev_err(fifo->dt_device, "user read buffer too small (available bytes=%zu user buffer bytes=%zu) - fifo core will be reset\n",
 396                         bytes_available, len);
 397                 reset_ip_core(fifo);
 398                 return -EINVAL;
 399         }
 400
 401         if (bytes_available % sizeof(u32)) {
 402                 /* this probably can't happen unless IP
 403                  * registers were previously mishandled
 404                  */
 405                 dev_err(fifo->dt_device, "received a packet that isn't word-aligned - fifo core will be reset\n");
 406                 reset_ip_core(fifo);
 407                 return -EIO;
 408         }
 409
 410         words_available = bytes_available / sizeof(u32);
 411
 412         /* read data into an intermediate buffer, copying the contents
 413          * to userspace when the buffer is full
 414          */
 415         copied = 0;
 416         while (words_available > 0) {
 417                 copy = min(words_available, READ_BUF_SIZE);
 418
 419                 for (i = 0; i < copy; i++) {
 420                         tmp_buf[i] = ioread32(fifo->base_addr +
 421                                               XLLF_RDFD_OFFSET);
 422                 }
 423
 424                 if (copy_to_user(buf + copied * sizeof(u32), tmp_buf,
 425                                  copy * sizeof(u32))) {
 426                         reset_ip_core(fifo);
 427                         return -EFAULT;
 428                 }
 429
 430                 copied += copy;
 431                 words_available -= copy;
 432         }
 433
 434         return bytes_available;
 435 }
 436
 437 static ssize_t axis_fifo_write(struct file *f, const char __user *buf,
 438                                size_t len, loff_t *off)
 439 {
 440         struct axis_fifo *fifo = (struct axis_fifo *)f->private_data;
 441         unsigned int words_to_write;
 442         unsigned int copied;
 443         unsigned int copy;
 444         unsigned int i;
 445         int ret;
 446         u32 tmp_buf[WRITE_BUF_SIZE];
 447
 448         if (len % sizeof(u32)) {
 449                 dev_err(fifo->dt_device,
 450                         "tried to send a packet that isn't word-aligned\n");
 451                 return -EINVAL;
 452         }
 453
 454         words_to_write = len / sizeof(u32);
 455
 456         if (!words_to_write) {
 457                 dev_err(fifo->dt_device,
 458                         "tried to send a packet of length 0\n");
 459                 return -EINVAL;
 460         }
 461
 462         if (words_to_write > fifo->tx_fifo_depth) {
 463                 dev_err(fifo->dt_device, "tried to write more words [%u] than slots in the fifo buffer [%u]\n",
 464                         words_to_write, fifo->tx_fifo_depth);
 465                 return -EINVAL;
 466         }
 467
 468         if (fifo->write_flags & O_NONBLOCK) {
 469                 /* opened in non-blocking mode
 470                  * return if there is not enough room available in the fifo
 471                  */
 472                 if (words_to_write > ioread32(fifo->base_addr +
 473                                               XLLF_TDFV_OFFSET)) {
 474                         return -EAGAIN;
 475                 }
 476         } else {
 477                 /* opened in blocking mode */
 478
 479                 /* wait for an interrupt (or timeout) if there isn't
 480                  * currently enough room in the fifo
 481                  */
 482                 spin_lock_irq(&fifo->write_queue_lock);
 483                 ret = wait_event_interruptible_lock_irq_timeout
 484                         (fifo->write_queue,
 485                          ioread32(fifo->base_addr + XLLF_TDFV_OFFSET)
 486                                 >= words_to_write,
 487                          fifo->write_queue_lock,
 488                          (write_timeout >= 0) ?
 489                                 msecs_to_jiffies(write_timeout) :
 490                                 MAX_SCHEDULE_TIMEOUT);
 491                 spin_unlock_irq(&fifo->write_queue_lock);
 492
 493                 if (ret == 0) {
 494                         /* timeout occurred */
 495                         dev_dbg(fifo->dt_device, "write timeout\n");
 496                         return -EAGAIN;
 497                 } else if (ret == -ERESTARTSYS) {
 498                         /* signal received */
 499                         return -ERESTARTSYS;
 500                 } else if (ret < 0) {
 501                         /* unknown error */
 502                         dev_err(fifo->dt_device,
 503                                 "wait_event_interruptible_timeout() error in write (ret=%i)\n",
 504                                 ret);
 505                         return ret;
 506                 }
 507         }
 508
 509         /* write data from an intermediate buffer into the fifo IP, refilling
 510          * the buffer with userspace data as needed
 511          */
 512         copied = 0;
 513         while (words_to_write > 0) {
 514                 copy = min(words_to_write, WRITE_BUF_SIZE);
 515
 516                 if (copy_from_user(tmp_buf, buf + copied * sizeof(u32),
 517                                    copy * sizeof(u32))) {
 518                         reset_ip_core(fifo);
 519                         return -EFAULT;
 520                 }
 521
 522                 for (i = 0; i < copy; i++)
 523                         iowrite32(tmp_buf[i], fifo->base_addr +
 524                                   XLLF_TDFD_OFFSET);
 525
 526                 copied += copy;
 527                 words_to_write -= copy;
 528         }
 529
 530         /* write packet size to fifo */
 531         iowrite32(copied * sizeof(u32), fifo->base_addr + XLLF_TLR_OFFSET);
 532
 533         return (ssize_t)copied * sizeof(u32);
 534 }
 535
 536 static irqreturn_t axis_fifo_irq(int irq, void *dw)
 537 {
 538         struct axis_fifo *fifo = (struct axis_fifo *)dw;
 539         unsigned int pending_interrupts;
 540
 541         do {
 542                 pending_interrupts = ioread32(fifo->base_addr +
 543                                               XLLF_IER_OFFSET) &
 544                                               ioread32(fifo->base_addr
 545                                               + XLLF_ISR_OFFSET);
 546                 if (pending_interrupts & XLLF_INT_RC_MASK) {
 547                         /* packet received */
 548
 549                         /* wake the reader process if it is waiting */
 550                         wake_up(&fifo->read_queue);
 551
 552                         /* clear interrupt */
 553                         iowrite32(XLLF_INT_RC_MASK & XLLF_INT_ALL_MASK,
 554                                   fifo->base_addr + XLLF_ISR_OFFSET);
 555                 } else if (pending_interrupts & XLLF_INT_TC_MASK) {
 556                         /* packet sent */
 557
 558                         /* wake the writer process if it is waiting */
 559                         wake_up(&fifo->write_queue);
 560
 561                         iowrite32(XLLF_INT_TC_MASK & XLLF_INT_ALL_MASK,
 562                                   fifo->base_addr + XLLF_ISR_OFFSET);
 563                 } else if (pending_interrupts & XLLF_INT_TFPF_MASK) {
 564                         /* transmit fifo programmable full */
 565
 566                         iowrite32(XLLF_INT_TFPF_MASK & XLLF_INT_ALL_MASK,
 567                                   fifo->base_addr + XLLF_ISR_OFFSET);
 568                 } else if (pending_interrupts & XLLF_INT_TFPE_MASK) {
 569                         /* transmit fifo programmable empty */
 570
 571                         iowrite32(XLLF_INT_TFPE_MASK & XLLF_INT_ALL_MASK,
 572                                   fifo->base_addr + XLLF_ISR_OFFSET);
 573                 } else if (pending_interrupts & XLLF_INT_RFPF_MASK) {
 574                         /* receive fifo programmable full */
 575
 576                         iowrite32(XLLF_INT_RFPF_MASK & XLLF_INT_ALL_MASK,
 577                                   fifo->base_addr + XLLF_ISR_OFFSET);
 578                 } else if (pending_interrupts & XLLF_INT_RFPE_MASK) {
 579                         /* receive fifo programmable empty */
 580
 581                         iowrite32(XLLF_INT_RFPE_MASK & XLLF_INT_ALL_MASK,
 582                                   fifo->base_addr + XLLF_ISR_OFFSET);
 583                 } else if (pending_interrupts & XLLF_INT_TRC_MASK) {
 584                         /* transmit reset complete interrupt */
 585
 586                         iowrite32(XLLF_INT_TRC_MASK & XLLF_INT_ALL_MASK,
 587                                   fifo->base_addr + XLLF_ISR_OFFSET);
 588                 } else if (pending_interrupts & XLLF_INT_RRC_MASK) {
 589                         /* receive reset complete interrupt */
 590
 591                         iowrite32(XLLF_INT_RRC_MASK & XLLF_INT_ALL_MASK,
 592                                   fifo->base_addr + XLLF_ISR_OFFSET);
 593                 } else if (pending_interrupts & XLLF_INT_RPURE_MASK) {
 594                         /* receive fifo under-read error interrupt */
 595                         dev_err(fifo->dt_device,
 596                                 "receive under-read interrupt\n");
 597
 598                         iowrite32(XLLF_INT_RPURE_MASK & XLLF_INT_ALL_MASK,
 599                                   fifo->base_addr + XLLF_ISR_OFFSET);
 600                 } else if (pending_interrupts & XLLF_INT_RPORE_MASK) {
 601                         /* receive over-read error interrupt */
 602                         dev_err(fifo->dt_device,
 603                                 "receive over-read interrupt\n");
 604
 605                         iowrite32(XLLF_INT_RPORE_MASK & XLLF_INT_ALL_MASK,
 606                                   fifo->base_addr + XLLF_ISR_OFFSET);
 607                 } else if (pending_interrupts & XLLF_INT_RPUE_MASK) {
 608                         /* receive underrun error interrupt */
 609                         dev_err(fifo->dt_device,
 610                                 "receive underrun error interrupt\n");
 611
 612                         iowrite32(XLLF_INT_RPUE_MASK & XLLF_INT_ALL_MASK,
 613                                   fifo->base_addr + XLLF_ISR_OFFSET);
 614                 } else if (pending_interrupts & XLLF_INT_TPOE_MASK) {
 615                         /* transmit overrun error interrupt */
 616                         dev_err(fifo->dt_device,
 617                                 "transmit overrun error interrupt\n");
 618
 619                         iowrite32(XLLF_INT_TPOE_MASK & XLLF_INT_ALL_MASK,
 620                                   fifo->base_addr + XLLF_ISR_OFFSET);
 621                 } else if (pending_interrupts & XLLF_INT_TSE_MASK) {
 622                         /* transmit length mismatch error interrupt */
 623                         dev_err(fifo->dt_device,
 624                                 "transmit length mismatch error interrupt\n");
 625
 626                         iowrite32(XLLF_INT_TSE_MASK & XLLF_INT_ALL_MASK,
 627                                   fifo->base_addr + XLLF_ISR_OFFSET);
 628                 } else if (pending_interrupts) {
 629                         /* unknown interrupt type */
 630                         dev_err(fifo->dt_device,
 631                                 "unknown interrupt(s) 0x%x\n",
 632                                 pending_interrupts);
 633
 634                         iowrite32(XLLF_INT_ALL_MASK,
 635                                   fifo->base_addr + XLLF_ISR_OFFSET);
 636                 }
 637         } while (pending_interrupts);
 638
 639         return IRQ_HANDLED;
 640 }
 641
 642 static int axis_fifo_open(struct inode *inod, struct file *f)
 643 {
 644         struct axis_fifo *fifo = (struct axis_fifo *)container_of(inod->i_cdev,
 645                                         struct axis_fifo, char_device);
 646         f->private_data = fifo;
 647
 648         if (((f->f_flags & O_ACCMODE) == O_WRONLY) ||
 649             ((f->f_flags & O_ACCMODE) == O_RDWR)) {
 650                 if (fifo->has_tx_fifo) {
 651                         fifo->write_flags = f->f_flags;
 652                 } else {
 653                         dev_err(fifo->dt_device, "tried to open device for write but the transmit fifo is disabled\n");
 654                         return -EPERM;
 655                 }
 656         }
 657
 658         if (((f->f_flags & O_ACCMODE) == O_RDONLY) ||
 659             ((f->f_flags & O_ACCMODE) == O_RDWR)) {
 660                 if (fifo->has_rx_fifo) {
 661                         fifo->read_flags = f->f_flags;
 662                 } else {
 663                         dev_err(fifo->dt_device, "tried to open device for read but the receive fifo is disabled\n");
 664                         return -EPERM;
 665                 }
 666         }
 667
 668         return 0;
 669 }
 670
 671 static int axis_fifo_close(struct inode *inod, struct file *f)
 672 {
 673         f->private_data = NULL;
 674
 675         return 0;
 676 }
 677
 678 static const struct file_operations fops = {
 679         .owner = THIS_MODULE,
 680         .open = axis_fifo_open,
 681         .release = axis_fifo_close,
 682         .read = axis_fifo_read,
 683         .write = axis_fifo_write
 684 };
 685
 686 /* read named property from the device tree */
 687 static int get_dts_property(struct axis_fifo *fifo,
 688                             char *name, unsigned int *var)
 689 {
 690         int rc;
 691
 692         rc = of_property_read_u32(fifo->dt_device->of_node, name, var);
 693         if (rc) {
 694                 dev_err(fifo->dt_device, "couldn't read IP dts property '%s'",
 695                         name);
 696                 return rc;
 697         }
 698         dev_dbg(fifo->dt_device, "dts property '%s' = %u\n",
 699                 name, *var);
 700
 701         return 0;
 702 }
 703
 704 static int axis_fifo_probe(struct platform_device *pdev)
 705 {
 706         struct resource *r_irq; /* interrupt resources */
 707         struct resource *r_mem; /* IO mem resources */
 708         struct device *dev = &pdev->dev; /* OS device (from device tree) */
 709         struct axis_fifo *fifo = NULL;
 710
 711         char device_name[32];
 712
 713         int rc = 0; /* error return value */
 714
 715         /* IP properties from device tree */
 716         unsigned int rxd_tdata_width;
 717         unsigned int txc_tdata_width;
 718         unsigned int txd_tdata_width;
 719         unsigned int tdest_width;
 720         unsigned int tid_width;
 721         unsigned int tuser_width;
 722         unsigned int data_interface_type;
 723         unsigned int has_tdest;
 724         unsigned int has_tid;
 725         unsigned int has_tkeep;
 726         unsigned int has_tstrb;
 727         unsigned int has_tuser;
 728         unsigned int rx_fifo_depth;
 729         unsigned int rx_programmable_empty_threshold;
 730         unsigned int rx_programmable_full_threshold;
 731         unsigned int axi_id_width;
 732         unsigned int axi4_data_width;
 733         unsigned int select_xpm;
 734         unsigned int tx_fifo_depth;
 735         unsigned int tx_programmable_empty_threshold;
 736         unsigned int tx_programmable_full_threshold;
 737         unsigned int use_rx_cut_through;
 738         unsigned int use_rx_data;
 739         unsigned int use_tx_control;
 740         unsigned int use_tx_cut_through;
 741         unsigned int use_tx_data;
 742
 743         /* ----------------------------
 744          *     init wrapper device
 745          * ----------------------------
 746          */
 747
 748         /* allocate device wrapper memory */
 749         fifo = devm_kmalloc(dev, sizeof(*fifo), GFP_KERNEL);
 750         if (!fifo)
 751                 return -ENOMEM;
 752
 753         dev_set_drvdata(dev, fifo);
 754         fifo->dt_device = dev;
 755
 756         init_waitqueue_head(&fifo->read_queue);
 757         init_waitqueue_head(&fifo->write_queue);
 758
 759         spin_lock_init(&fifo->read_queue_lock);
 760         spin_lock_init(&fifo->write_queue_lock);
 761
 762         /* ----------------------------
 763          *   init device memory space
 764          * ----------------------------
 765          */
 766
 767         /* get iospace for the device */
 768         r_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 769         if (!r_mem) {
 770                 dev_err(fifo->dt_device, "invalid address\n");
 771                 rc = -ENODEV;
 772                 goto err_initial;
 773         }
 774
 775         fifo->mem = r_mem;
 776
 777         /* request physical memory */
 778         if (!request_mem_region(fifo->mem->start, resource_size(fifo->mem),
 779                                 DRIVER_NAME)) {
 780                 dev_err(fifo->dt_device,
 781                         "couldn't lock memory region at 0x%pa\n",
 782                         &fifo->mem->start);
 783                 rc = -EBUSY;
 784                 goto err_initial;
 785         }
 786         dev_dbg(fifo->dt_device, "got memory location [0x%pa - 0x%pa]\n",
 787                 &fifo->mem->start, &fifo->mem->end);
 788
 789         /* map physical memory to kernel virtual address space */
 790         fifo->base_addr = ioremap(fifo->mem->start, resource_size(fifo->mem));
 791         if (!fifo->base_addr) {
 792                 dev_err(fifo->dt_device, "couldn't map physical memory\n");
 793                 rc = -ENOMEM;
 794                 goto err_mem;
 795         }
 796         dev_dbg(fifo->dt_device, "remapped memory to 0x%p\n", fifo->base_addr);
 797
 798         /* create unique device name */
 799         snprintf(device_name, sizeof(device_name), "%s_%pa",
 800                  DRIVER_NAME, &fifo->mem->start);
 801
 802         dev_dbg(fifo->dt_device, "device name [%s]\n", device_name);
 803
 804         /* ----------------------------
 805          *          init IP
 806          * ----------------------------
 807          */
 808
 809         /* retrieve device tree properties */
 810         rc = get_dts_property(fifo, "xlnx,axi-str-rxd-tdata-width",
 811                               &rxd_tdata_width);
 812         if (rc)
 813                 goto err_unmap;
 814         rc = get_dts_property(fifo, "xlnx,axi-str-txc-tdata-width",
 815                               &txc_tdata_width);
 816         if (rc)
 817                 goto err_unmap;
 818         rc = get_dts_property(fifo, "xlnx,axi-str-txd-tdata-width",
 819                               &txd_tdata_width);
 820         if (rc)
 821                 goto err_unmap;
 822         rc = get_dts_property(fifo, "xlnx,axis-tdest-width", &tdest_width);
 823         if (rc)
 824                 goto err_unmap;
 825         rc = get_dts_property(fifo, "xlnx,axis-tid-width", &tid_width);
 826         if (rc)
 827                 goto err_unmap;
 828         rc = get_dts_property(fifo, "xlnx,axis-tuser-width", &tuser_width);
 829         if (rc)
 830                 goto err_unmap;
 831         rc = get_dts_property(fifo, "xlnx,data-interface-type",
 832                               &data_interface_type);
 833         if (rc)
 834                 goto err_unmap;
 835         rc = get_dts_property(fifo, "xlnx,has-axis-tdest", &has_tdest);
 836         if (rc)
 837                 goto err_unmap;
 838         rc = get_dts_property(fifo, "xlnx,has-axis-tid", &has_tid);
 839         if (rc)
 840                 goto err_unmap;
 841         rc = get_dts_property(fifo, "xlnx,has-axis-tkeep", &has_tkeep);
 842         if (rc)
 843                 goto err_unmap;
 844         rc = get_dts_property(fifo, "xlnx,has-axis-tstrb", &has_tstrb);
 845         if (rc)
 846                 goto err_unmap;
 847         rc = get_dts_property(fifo, "xlnx,has-axis-tuser", &has_tuser);
 848         if (rc)
 849                 goto err_unmap;
 850         rc = get_dts_property(fifo, "xlnx,rx-fifo-depth", &rx_fifo_depth);
 851         if (rc)
 852                 goto err_unmap;
 853         rc = get_dts_property(fifo, "xlnx,rx-fifo-pe-threshold",
 854                               &rx_programmable_empty_threshold);
 855         if (rc)
 856                 goto err_unmap;
 857         rc = get_dts_property(fifo, "xlnx,rx-fifo-pf-threshold",
 858                               &rx_programmable_full_threshold);
 859         if (rc)
 860                 goto err_unmap;
 861         rc = get_dts_property(fifo, "xlnx,s-axi-id-width", &axi_id_width);
 862         if (rc)
 863                 goto err_unmap;
 864         rc = get_dts_property(fifo, "xlnx,s-axi4-data-width", &axi4_data_width);
 865         if (rc)
 866                 goto err_unmap;
 867         rc = get_dts_property(fifo, "xlnx,select-xpm", &select_xpm);
 868         if (rc)
 869                 goto err_unmap;
 870         rc = get_dts_property(fifo, "xlnx,tx-fifo-depth", &tx_fifo_depth);
 871         if (rc)
 872                 goto err_unmap;
 873         rc = get_dts_property(fifo, "xlnx,tx-fifo-pe-threshold",
 874                               &tx_programmable_empty_threshold);
 875         if (rc)
 876                 goto err_unmap;
 877         rc = get_dts_property(fifo, "xlnx,tx-fifo-pf-threshold",
 878                               &tx_programmable_full_threshold);
 879         if (rc)
 880                 goto err_unmap;
 881         rc = get_dts_property(fifo, "xlnx,use-rx-cut-through",
 882                               &use_rx_cut_through);
 883         if (rc)
 884                 goto err_unmap;
 885         rc = get_dts_property(fifo, "xlnx,use-rx-data", &use_rx_data);
 886         if (rc)
 887                 goto err_unmap;
 888         rc = get_dts_property(fifo, "xlnx,use-tx-ctrl", &use_tx_control);
 889         if (rc)
 890                 goto err_unmap;
 891         rc = get_dts_property(fifo, "xlnx,use-tx-cut-through",
 892                               &use_tx_cut_through);
 893         if (rc)
 894                 goto err_unmap;
 895         rc = get_dts_property(fifo, "xlnx,use-tx-data", &use_tx_data);
 896         if (rc)
 897                 goto err_unmap;
 898
 899         /* check validity of device tree properties */
 900         if (rxd_tdata_width != 32) {
 901                 dev_err(fifo->dt_device,
 902                         "rxd_tdata_width width [%u] unsupported\n",
 903                         rxd_tdata_width);
 904                 rc = -EIO;
 905                 goto err_unmap;
 906         }
 907         if (txd_tdata_width != 32) {
 908                 dev_err(fifo->dt_device,
 909                         "txd_tdata_width width [%u] unsupported\n",
 910                         txd_tdata_width);
 911                 rc = -EIO;
 912                 goto err_unmap;
 913         }
 914         if (has_tdest) {
 915                 dev_err(fifo->dt_device, "tdest not supported\n");
 916                 rc = -EIO;
 917                 goto err_unmap;
 918         }
 919         if (has_tid) {
 920                 dev_err(fifo->dt_device, "tid not supported\n");
 921                 rc = -EIO;
 922                 goto err_unmap;
 923         }
 924         if (has_tkeep) {
 925                 dev_err(fifo->dt_device, "tkeep not supported\n");
 926                 rc = -EIO;
 927                 goto err_unmap;
 928         }
 929         if (has_tstrb) {
 930                 dev_err(fifo->dt_device, "tstrb not supported\n");
 931                 rc = -EIO;
 932                 goto err_unmap;
 933         }
 934         if (has_tuser) {
 935                 dev_err(fifo->dt_device, "tuser not supported\n");
 936                 rc = -EIO;
 937                 goto err_unmap;
 938         }
 939         if (use_rx_cut_through) {
 940                 dev_err(fifo->dt_device, "rx cut-through not supported\n");
 941                 rc = -EIO;
 942                 goto err_unmap;
 943         }
 944         if (use_tx_cut_through) {
 945                 dev_err(fifo->dt_device, "tx cut-through not supported\n");
 946                 rc = -EIO;
 947                 goto err_unmap;
 948         }
 949         if (use_tx_control) {
 950                 dev_err(fifo->dt_device, "tx control not supported\n");
 951                 rc = -EIO;
 952                 goto err_unmap;
 953         }
 954
 955         /* TODO
 956          * these exist in the device tree but it's unclear what they do
 957          * - select-xpm
 958          * - data-interface-type
 959          */
 960
 961         /* set device wrapper properties based on IP config */
 962         fifo->rx_fifo_depth = rx_fifo_depth;
 963         /* IP sets TDFV to fifo depth - 4 so we will do the same */
 964         fifo->tx_fifo_depth = tx_fifo_depth - 4;
 965         fifo->has_rx_fifo = use_rx_data;
 966         fifo->has_tx_fifo = use_tx_data;
 967
 968         reset_ip_core(fifo);
 969
 970         /* ----------------------------
 971          *    init device interrupts
 972          * ----------------------------
 973          */
 974
 975         /* get IRQ resource */
 976         r_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 977         if (!r_irq) {
 978                 dev_err(fifo->dt_device, "no IRQ found for 0x%pa\n",
 979                         &fifo->mem->start);
 980                 rc = -EIO;
 981                 goto err_unmap;
 982         }
 983
 984         /* request IRQ */
 985         fifo->irq = r_irq->start;
 986         rc = request_irq(fifo->irq, &axis_fifo_irq, 0, DRIVER_NAME, fifo);
 987         if (rc) {
 988                 dev_err(fifo->dt_device, "couldn't allocate interrupt %i\n",
 989                         fifo->irq);
 990                 goto err_unmap;
 991         }
 992
 993         /* ----------------------------
 994          *      init char device
 995          * ----------------------------
 996          */
 997
 998         /* allocate device number */
 999         rc = alloc_chrdev_region(&fifo->devt, 0, 1, DRIVER_NAME);
1000         if (rc < 0)
1001                 goto err_irq;
1002         dev_dbg(fifo->dt_device, "allocated device number major %i minor %i\n",
1003                 MAJOR(fifo->devt), MINOR(fifo->devt));
1004
1005         /* create driver file */
1006         fifo->device = device_create(axis_fifo_driver_class, NULL, fifo->devt,
1007                                      NULL, device_name);
1008         if (IS_ERR(fifo->device)) {
1009                 dev_err(fifo->dt_device,
1010                         "couldn't create driver file\n");
1011                 rc = PTR_ERR(fifo->device);
1012                 goto err_chrdev_region;
1013         }
1014         dev_set_drvdata(fifo->device, fifo);
1015
1016         /* create character device */
1017         cdev_init(&fifo->char_device, &fops);
1018         rc = cdev_add(&fifo->char_device, fifo->devt, 1);
1019         if (rc < 0) {
1020                 dev_err(fifo->dt_device, "couldn't create character device\n");
1021                 goto err_dev;
1022         }
1023
1024         /* create sysfs entries */
1025         rc = sysfs_create_group(&fifo->device->kobj, &axis_fifo_attrs_group);
1026         if (rc < 0) {
1027                 dev_err(fifo->dt_device, "couldn't register sysfs group\n");
1028                 goto err_cdev;
1029         }
1030
1031         dev_info(fifo->dt_device, "axis-fifo created at %pa mapped to 0x%pa, irq=%i, major=%i, minor=%i\n",
1032                  &fifo->mem->start, &fifo->base_addr, fifo->irq,
1033                  MAJOR(fifo->devt), MINOR(fifo->devt));
1034
1035         return 0;
1036
1037 err_cdev:
1038         cdev_del(&fifo->char_device);
1039 err_dev:
1040         device_destroy(axis_fifo_driver_class, fifo->devt);
1041 err_chrdev_region:
1042         unregister_chrdev_region(fifo->devt, 1);
1043 err_irq:
1044         free_irq(fifo->irq, fifo);
1045 err_unmap:
1046         iounmap(fifo->base_addr);
1047 err_mem:
1048         release_mem_region(fifo->mem->start, resource_size(fifo->mem));
1049 err_initial:
1050         dev_set_drvdata(dev, NULL);
1051         return rc;
1052 }
1053
1054 static int axis_fifo_remove(struct platform_device *pdev)
1055 {
1056         struct device *dev = &pdev->dev;
1057         struct axis_fifo *fifo = dev_get_drvdata(dev);
1058
1059         sysfs_remove_group(&fifo->device->kobj, &axis_fifo_attrs_group);
1060         cdev_del(&fifo->char_device);
1061         dev_set_drvdata(fifo->device, NULL);
1062         device_destroy(axis_fifo_driver_class, fifo->devt);
1063         unregister_chrdev_region(fifo->devt, 1);
1064         free_irq(fifo->irq, fifo);
1065         iounmap(fifo->base_addr);
1066         release_mem_region(fifo->mem->start, resource_size(fifo->mem));
1067         dev_set_drvdata(dev, NULL);
1068         return 0;
1069 }
1070
1071 static const struct of_device_id axis_fifo_of_match[] = {
1072         { .compatible = "xlnx,axi-fifo-mm-s-4.1", },
1073         {},
1074 };
1075 MODULE_DEVICE_TABLE(of, axis_fifo_of_match);
1076
1077 static struct platform_driver axis_fifo_driver = {
1078         .driver = {
1079                 .name = DRIVER_NAME,
1080                 .of_match_table = axis_fifo_of_match,
1081         },
1082         .probe          = axis_fifo_probe,
1083         .remove         = axis_fifo_remove,
1084 };
1085
1086 static int __init axis_fifo_init(void)
1087 {
1088         pr_info("axis-fifo driver loaded with parameters read_timeout = %i, write_timeout = %i\n",
1089                 read_timeout, write_timeout);
1090         axis_fifo_driver_class = class_create(THIS_MODULE, DRIVER_NAME);
1091         if (IS_ERR(axis_fifo_driver_class))
1092                 return PTR_ERR(axis_fifo_driver_class);
1093         return platform_driver_register(&axis_fifo_driver);
1094 }
1095
1096 module_init(axis_fifo_init);
1097
1098 static void __exit axis_fifo_exit(void)
1099 {
1100         platform_driver_unregister(&axis_fifo_driver);
1101         class_destroy(axis_fifo_driver_class);
1102 }
1103
1104 module_exit(axis_fifo_exit);
1105
1106 MODULE_LICENSE("GPL");
1107 MODULE_AUTHOR("Jacob Feder <jacobsfeder@gmail.com>");
1108 MODULE_DESCRIPTION("Xilinx AXI-Stream FIFO v4.1 IP core driver");