drivers/char/msm_smd_pkt.c

   1 /* Copyright (c) 2008-2010, Code Aurora Forum. All rights reserved.
   2  *
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License version 2 and
   5  * only version 2 as published by the Free Software Foundation.
   6  *
   7  * This program is distributed in the hope that it will be useful,
   8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10  * GNU General Public License for more details.
  11  *
  12  * You should have received a copy of the GNU General Public License
  13  * along with this program; if not, write to the Free Software
  14  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  15  * 02110-1301, USA.
  16  *
  17  */
  18 /*
  19  * SMD Packet Driver -- Provides userspace interface to SMD packet ports.
  20  */
  21
  22 #include <linux/slab.h>
  23 #include <linux/cdev.h>
  24 #include <linux/module.h>
  25 #include <linux/fs.h>
  26 #include <linux/device.h>
  27 #include <linux/sched.h>
  28 #include <linux/mutex.h>
  29 #include <linux/delay.h>
  30 #include <linux/uaccess.h>
  31 #include <linux/workqueue.h>
  32 #include <linux/poll.h>
  33
  34 #include <mach/msm_smd.h>
  35
  36 #define NUM_SMD_PKT_PORTS 9
  37 #define DEVICE_NAME "smdpkt"
  38 #define MAX_BUF_SIZE 2048
  39
  40 struct smd_pkt_dev {
  41         struct cdev cdev;
  42         struct device *devicep;
  43
  44         struct smd_channel *ch;
  45         int open_count;
  46         struct mutex ch_lock;
  47         struct mutex rx_lock;
  48         struct mutex tx_lock;
  49         wait_queue_head_t ch_read_wait_queue;
  50         wait_queue_head_t ch_opened_wait_queue;
  51
  52         int i;
  53
  54         unsigned char tx_buf[MAX_BUF_SIZE];
  55         unsigned char rx_buf[MAX_BUF_SIZE];
  56         int remote_open;
  57
  58 } *smd_pkt_devp[NUM_SMD_PKT_PORTS];
  59
  60 struct class *smd_pkt_classp;
  61 static dev_t smd_pkt_number;
  62
  63 static int msm_smd_pkt_debug_enable;
  64 module_param_named(debug_enable, msm_smd_pkt_debug_enable,
  65                    int, S_IRUGO | S_IWUSR | S_IWGRP);
  66
  67 #ifdef DEBUG
  68 #define D_DUMP_BUFFER(prestr, cnt, buf) do {                    \
  69                 int i;                                          \
  70                 if (msm_smd_pkt_debug_enable) {                 \
  71                         pr_debug("%s", prestr);                 \
  72                         for (i = 0; i < cnt; i++)               \
  73                                 pr_debug("%.2x", buf[i]);       \
  74                         pr_debug("\n");                         \
  75                 }                                               \
  76         } while (0)
  77 #else
  78 #define D_DUMP_BUFFER(prestr, cnt, buf) do {} while (0)
  79 #endif
  80
  81 #ifdef DEBUG
  82 #define DBG(x...) do {                  \
  83         if (msm_smd_pkt_debug_enable)   \
  84                 pr_debug(x);            \
  85         } while (0)
  86 #else
  87 #define DBG(x...) do {} while (0)
  88 #endif
  89
  90 static void check_and_wakeup_reader(struct smd_pkt_dev *smd_pkt_devp)
  91 {
  92         int sz;
  93
  94         if (!smd_pkt_devp || !smd_pkt_devp->ch)
  95                 return;
  96
  97         sz = smd_cur_packet_size(smd_pkt_devp->ch);
  98         if (sz == 0) {
  99                 DBG("no packet\n");
 100                 return;
 101         }
 102         if (sz > smd_read_avail(smd_pkt_devp->ch)) {
 103                 DBG("incomplete packet\n");
 104                 return;
 105         }
 106
 107         DBG("waking up reader\n");
 108         wake_up_interruptible(&smd_pkt_devp->ch_read_wait_queue);
 109 }
 110
 111 static int smd_pkt_read(struct file *file, char __user *buf,
 112                         size_t count, loff_t *ppos)
 113 {
 114         int r, bytes_read;
 115         struct smd_pkt_dev *smd_pkt_devp;
 116         struct smd_channel *chl;
 117
 118         DBG("read %d bytes\n", count);
 119         if (count > MAX_BUF_SIZE)
 120                 return -EINVAL;
 121
 122         smd_pkt_devp = file->private_data;
 123         if (!smd_pkt_devp || !smd_pkt_devp->ch)
 124                 return -EINVAL;
 125
 126         chl = smd_pkt_devp->ch;
 127 wait_for_packet:
 128         r = wait_event_interruptible(smd_pkt_devp->ch_read_wait_queue,
 129                                      (smd_cur_packet_size(chl) > 0 &&
 130                                       smd_read_avail(chl) >=
 131                                       smd_cur_packet_size(chl)));
 132
 133         if (r < 0) {
 134                 if (r != -ERESTARTSYS)
 135                         pr_err("wait returned %d\n", r);
 136                 return r;
 137         }
 138
 139         mutex_lock(&smd_pkt_devp->rx_lock);
 140
 141         bytes_read = smd_cur_packet_size(smd_pkt_devp->ch);
 142         if (bytes_read == 0 ||
 143             bytes_read < smd_read_avail(smd_pkt_devp->ch)) {
 144                 mutex_unlock(&smd_pkt_devp->rx_lock);
 145                 DBG("Nothing to read\n");
 146                 goto wait_for_packet;
 147         }
 148
 149         if (bytes_read > count) {
 150                 mutex_unlock(&smd_pkt_devp->rx_lock);
 151                 pr_info("packet size %d > buffer size %d", bytes_read, count);
 152                 return -EINVAL;
 153         }
 154
 155         r = smd_read(smd_pkt_devp->ch, smd_pkt_devp->rx_buf, bytes_read);
 156         if (r != bytes_read) {
 157                 mutex_unlock(&smd_pkt_devp->rx_lock);
 158                 pr_err("smd_read failed to read %d bytes: %d\n", bytes_read, r);
 159                 return -EIO;
 160         }
 161
 162         D_DUMP_BUFFER("read: ", bytes_read, smd_pkt_devp->rx_buf);
 163         r = copy_to_user(buf, smd_pkt_devp->rx_buf, bytes_read);
 164         mutex_unlock(&smd_pkt_devp->rx_lock);
 165         if (r) {
 166                 pr_err("copy_to_user failed %d\n", r);
 167                 return -EFAULT;
 168         }
 169
 170         DBG("read complete %d bytes\n", bytes_read);
 171         check_and_wakeup_reader(smd_pkt_devp);
 172
 173         return bytes_read;
 174 }
 175
 176 static int smd_pkt_write(struct file *file, const char __user *buf,
 177                          size_t count, loff_t *ppos)
 178 {
 179         int r;
 180         struct smd_pkt_dev *smd_pkt_devp;
 181
 182         if (count > MAX_BUF_SIZE)
 183                 return -EINVAL;
 184
 185         DBG("writting %d bytes\n", count);
 186
 187         smd_pkt_devp = file->private_data;
 188         if (!smd_pkt_devp || !smd_pkt_devp->ch)
 189                 return -EINVAL;
 190
 191         mutex_lock(&smd_pkt_devp->tx_lock);
 192         if (smd_write_avail(smd_pkt_devp->ch) < count) {
 193                 mutex_unlock(&smd_pkt_devp->tx_lock);
 194                 DBG("Not enough space to write\n");
 195                 return -ENOMEM;
 196         }
 197
 198         D_DUMP_BUFFER("write: ", count, buf);
 199         r = copy_from_user(smd_pkt_devp->tx_buf, buf, count);
 200         if (r) {
 201                 mutex_unlock(&smd_pkt_devp->tx_lock);
 202                 pr_err("copy_from_user failed %d\n", r);
 203                 return -EFAULT;
 204         }
 205
 206         r = smd_write(smd_pkt_devp->ch, smd_pkt_devp->tx_buf, count);
 207         if (r != count) {
 208                 mutex_unlock(&smd_pkt_devp->tx_lock);
 209                 pr_err("smd_write failed to write %d bytes: %d.\n", count, r);
 210                 return -EIO;
 211         }
 212         mutex_unlock(&smd_pkt_devp->tx_lock);
 213
 214         DBG("wrote %d bytes\n", count);
 215         return count;
 216 }
 217
 218 static unsigned int smd_pkt_poll(struct file *file, poll_table *wait)
 219 {
 220         struct smd_pkt_dev *smd_pkt_devp;
 221         unsigned int mask = 0;
 222
 223         smd_pkt_devp = file->private_data;
 224         if (!smd_pkt_devp)
 225                 return POLLERR;
 226
 227         DBG("poll waiting\n");
 228         poll_wait(file, &smd_pkt_devp->ch_read_wait_queue, wait);
 229         if (smd_read_avail(smd_pkt_devp->ch))
 230                 mask |= POLLIN | POLLRDNORM;
 231
 232         DBG("poll return\n");
 233         return mask;
 234 }
 235
 236 static void smd_pkt_ch_notify(void *priv, unsigned event)
 237 {
 238         struct smd_pkt_dev *smd_pkt_devp = priv;
 239
 240         if (smd_pkt_devp->ch == 0)
 241                 return;
 242
 243         switch (event) {
 244         case SMD_EVENT_DATA:
 245                 DBG("data\n");
 246                 check_and_wakeup_reader(smd_pkt_devp);
 247                 break;
 248
 249         case SMD_EVENT_OPEN:
 250                 DBG("remote open\n");
 251                 smd_pkt_devp->remote_open = 1;
 252                 wake_up_interruptible(&smd_pkt_devp->ch_opened_wait_queue);
 253                 break;
 254
 255         case SMD_EVENT_CLOSE:
 256                 smd_pkt_devp->remote_open = 0;
 257                 pr_info("remote closed\n");
 258                 break;
 259
 260         default:
 261                 pr_err("unknown event %d\n", event);
 262                 break;
 263         }
 264 }
 265
 266 static char *smd_pkt_dev_name[] = {
 267         "smdcntl0",
 268         "smdcntl1",
 269         "smdcntl2",
 270         "smdcntl3",
 271         "smdcntl4",
 272         "smdcntl5",
 273         "smdcntl6",
 274         "smdcntl7",
 275         "smd22",
 276 };
 277
 278 static char *smd_ch_name[] = {
 279         "DATA5_CNTL",
 280         "DATA6_CNTL",
 281         "DATA7_CNTL",
 282         "DATA8_CNTL",
 283         "DATA9_CNTL",
 284         "DATA12_CNTL",
 285         "DATA13_CNTL",
 286         "DATA14_CNTL",
 287         "DATA22",
 288 };
 289
 290 static int smd_pkt_open(struct inode *inode, struct file *file)
 291 {
 292         int r = 0;
 293         struct smd_pkt_dev *smd_pkt_devp;
 294
 295         smd_pkt_devp = container_of(inode->i_cdev, struct smd_pkt_dev, cdev);
 296         if (!smd_pkt_devp)
 297                 return -EINVAL;
 298
 299         file->private_data = smd_pkt_devp;
 300
 301         mutex_lock(&smd_pkt_devp->ch_lock);
 302         if (smd_pkt_devp->open_count == 0) {
 303                 r = smd_open(smd_ch_name[smd_pkt_devp->i],
 304                              &smd_pkt_devp->ch, smd_pkt_devp,
 305                              smd_pkt_ch_notify);
 306                 if (r < 0) {
 307                         pr_err("smd_open failed for %s, %d\n",
 308                                smd_ch_name[smd_pkt_devp->i], r);
 309                         goto out;
 310                 }
 311
 312                 r = wait_event_interruptible_timeout(
 313                                 smd_pkt_devp->ch_opened_wait_queue,
 314                                 smd_pkt_devp->remote_open,
 315                                 msecs_to_jiffies(2 * HZ));
 316                 if (r == 0)
 317                         r = -ETIMEDOUT;
 318
 319                 if (r < 0) {
 320                         pr_err("wait returned %d\n", r);
 321                         smd_close(smd_pkt_devp->ch);
 322                         smd_pkt_devp->ch = 0;
 323                 } else {
 324                         smd_pkt_devp->open_count++;
 325                         r = 0;
 326                 }
 327         }
 328 out:
 329         mutex_unlock(&smd_pkt_devp->ch_lock);
 330         return r;
 331 }
 332
 333 static int smd_pkt_release(struct inode *inode, struct file *file)
 334 {
 335         int r = 0;
 336         struct smd_pkt_dev *smd_pkt_devp = file->private_data;
 337
 338         if (!smd_pkt_devp)
 339                 return -EINVAL;
 340
 341         mutex_lock(&smd_pkt_devp->ch_lock);
 342         if (--smd_pkt_devp->open_count == 0) {
 343                 r = smd_close(smd_pkt_devp->ch);
 344                 smd_pkt_devp->ch = 0;
 345         }
 346         mutex_unlock(&smd_pkt_devp->ch_lock);
 347
 348         return r;
 349 }
 350
 351 static const struct file_operations smd_pkt_fops = {
 352         .owner = THIS_MODULE,
 353         .open = smd_pkt_open,
 354         .release = smd_pkt_release,
 355         .read = smd_pkt_read,
 356         .write = smd_pkt_write,
 357         .poll = smd_pkt_poll,
 358 };
 359
 360 static int __init smd_pkt_init(void)
 361 {
 362         int i;
 363         int r;
 364
 365         r = alloc_chrdev_region(&smd_pkt_number, 0,
 366                                 NUM_SMD_PKT_PORTS, DEVICE_NAME);
 367         if (r) {
 368                 pr_err("alloc_chrdev_region() failed %d\n", r);
 369                 return r;
 370         }
 371
 372         smd_pkt_classp = class_create(THIS_MODULE, DEVICE_NAME);
 373         if (IS_ERR(smd_pkt_classp)) {
 374                 r = PTR_ERR(smd_pkt_classp);
 375                 pr_err("class_create() failed %d\n", r);
 376                 goto unreg_chardev;
 377         }
 378
 379         for (i = 0; i < NUM_SMD_PKT_PORTS; ++i) {
 380                 smd_pkt_devp[i] = kzalloc(sizeof(struct smd_pkt_dev),
 381                                           GFP_KERNEL);
 382                 if (!smd_pkt_devp[i]) {
 383                         pr_err("kmalloc() failed\n");
 384                         goto clean_cdevs;
 385                 }
 386
 387                 smd_pkt_devp[i]->i = i;
 388
 389                 init_waitqueue_head(&smd_pkt_devp[i]->ch_read_wait_queue);
 390                 smd_pkt_devp[i]->remote_open = 0;
 391                 init_waitqueue_head(&smd_pkt_devp[i]->ch_opened_wait_queue);
 392
 393                 mutex_init(&smd_pkt_devp[i]->ch_lock);
 394                 mutex_init(&smd_pkt_devp[i]->rx_lock);
 395                 mutex_init(&smd_pkt_devp[i]->tx_lock);
 396
 397                 cdev_init(&smd_pkt_devp[i]->cdev, &smd_pkt_fops);
 398                 smd_pkt_devp[i]->cdev.owner = THIS_MODULE;
 399
 400                 r = cdev_add(&smd_pkt_devp[i]->cdev,
 401                              (smd_pkt_number + i), 1);
 402                 if (r) {
 403                         pr_err("cdev_add() failed %d\n", r);
 404                         kfree(smd_pkt_devp[i]);
 405                         goto clean_cdevs;
 406                 }
 407
 408                 smd_pkt_devp[i]->devicep =
 409                         device_create(smd_pkt_classp, NULL,
 410                                       (smd_pkt_number + i), NULL,
 411                                       smd_pkt_dev_name[i]);
 412                 if (IS_ERR(smd_pkt_devp[i]->devicep)) {
 413                         r = PTR_ERR(smd_pkt_devp[i]->devicep);
 414                         pr_err("device_create() failed %d\n", r);
 415                         cdev_del(&smd_pkt_devp[i]->cdev);
 416                         kfree(smd_pkt_devp[i]);
 417                         goto clean_cdevs;
 418                 }
 419
 420         }
 421
 422         pr_info("SMD Packet Port Driver Initialized.\n");
 423         return 0;
 424
 425 clean_cdevs:
 426         if (i > 0) {
 427                 while (--i >= 0) {
 428                         mutex_destroy(&smd_pkt_devp[i]->ch_lock);
 429                         mutex_destroy(&smd_pkt_devp[i]->rx_lock);
 430                         mutex_destroy(&smd_pkt_devp[i]->tx_lock);
 431                         cdev_del(&smd_pkt_devp[i]->cdev);
 432                         kfree(smd_pkt_devp[i]);
 433                         device_destroy(smd_pkt_classp,
 434                                        MKDEV(MAJOR(smd_pkt_number), i));
 435                 }
 436         }
 437
 438         class_destroy(smd_pkt_classp);
 439 unreg_chardev:
 440         unregister_chrdev_region(MAJOR(smd_pkt_number), NUM_SMD_PKT_PORTS);
 441         return r;
 442 }
 443 module_init(smd_pkt_init);
 444
 445 static void __exit smd_pkt_cleanup(void)
 446 {
 447         int i;
 448
 449         for (i = 0; i < NUM_SMD_PKT_PORTS; ++i) {
 450                 mutex_destroy(&smd_pkt_devp[i]->ch_lock);
 451                 mutex_destroy(&smd_pkt_devp[i]->rx_lock);
 452                 mutex_destroy(&smd_pkt_devp[i]->tx_lock);
 453                 cdev_del(&smd_pkt_devp[i]->cdev);
 454                 kfree(smd_pkt_devp[i]);
 455                 device_destroy(smd_pkt_classp,
 456                                MKDEV(MAJOR(smd_pkt_number), i));
 457         }
 458
 459         class_destroy(smd_pkt_classp);
 460         unregister_chrdev_region(MAJOR(smd_pkt_number), NUM_SMD_PKT_PORTS);
 461 }
 462 module_exit(smd_pkt_cleanup);
 463
 464 MODULE_DESCRIPTION("MSM Shared Memory Packet Port");
 465 MODULE_LICENSE("GPL v2");