drivers/staging/ozwpan/ozcdev.c

   1 /* -----------------------------------------------------------------------------
   2  * Copyright (c) 2011 Ozmo Inc
   3  * Released under the GNU General Public License Version 2 (GPLv2).
   4  * -----------------------------------------------------------------------------
   5  */
   6 #include <linux/module.h>
   7 #include <linux/fs.h>
   8 #include <linux/cdev.h>
   9 #include <linux/uaccess.h>
  10 #include <linux/netdevice.h>
  11 #include <linux/etherdevice.h>
  12 #include <linux/poll.h>
  13 #include <linux/sched.h>
  14 #include "ozconfig.h"
  15 #include "ozprotocol.h"
  16 #include "oztrace.h"
  17 #include "ozappif.h"
  18 #include "ozeltbuf.h"
  19 #include "ozpd.h"
  20 #include "ozproto.h"
  21 #include "ozevent.h"
  22 #include "ozcdev.h"
  23 /*------------------------------------------------------------------------------
  24  */
  25 #define OZ_RD_BUF_SZ    256
  26 struct oz_cdev {
  27         dev_t devnum;
  28         struct cdev cdev;
  29         wait_queue_head_t rdq;
  30         spinlock_t lock;
  31         u8 active_addr[ETH_ALEN];
  32         struct oz_pd *active_pd;
  33 };
  34
  35 /* Per PD context for the serial service stored in the PD. */
  36 struct oz_serial_ctx {
  37         atomic_t ref_count;
  38         u8 tx_seq_num;
  39         u8 rx_seq_num;
  40         u8 rd_buf[OZ_RD_BUF_SZ];
  41         int rd_in;
  42         int rd_out;
  43 };
  44 /*------------------------------------------------------------------------------
  45  */
  46 static struct oz_cdev g_cdev;
  47 static struct class *g_oz_class;
  48 /*------------------------------------------------------------------------------
  49  * Context: process and softirq
  50  */
  51 static struct oz_serial_ctx *oz_cdev_claim_ctx(struct oz_pd *pd)
  52 {
  53         struct oz_serial_ctx *ctx;
  54         spin_lock_bh(&pd->app_lock[OZ_APPID_SERIAL-1]);
  55         ctx = (struct oz_serial_ctx *)pd->app_ctx[OZ_APPID_SERIAL-1];
  56         if (ctx)
  57                 atomic_inc(&ctx->ref_count);
  58         spin_unlock_bh(&pd->app_lock[OZ_APPID_SERIAL-1]);
  59         return ctx;
  60 }
  61 /*------------------------------------------------------------------------------
  62  * Context: softirq or process
  63  */
  64 static void oz_cdev_release_ctx(struct oz_serial_ctx *ctx)
  65 {
  66         if (atomic_dec_and_test(&ctx->ref_count)) {
  67                 oz_trace("Dealloc serial context.\n");
  68                 kfree(ctx);
  69         }
  70 }
  71 /*------------------------------------------------------------------------------
  72  * Context: process
  73  */
  74 static int oz_cdev_open(struct inode *inode, struct file *filp)
  75 {
  76         struct oz_cdev *dev;
  77         oz_trace("oz_cdev_open()\n");
  78         oz_trace("major = %d minor = %d\n", imajor(inode), iminor(inode));
  79         dev = container_of(inode->i_cdev, struct oz_cdev, cdev);
  80         filp->private_data = dev;
  81         return 0;
  82 }
  83 /*------------------------------------------------------------------------------
  84  * Context: process
  85  */
  86 static int oz_cdev_release(struct inode *inode, struct file *filp)
  87 {
  88         oz_trace("oz_cdev_release()\n");
  89         return 0;
  90 }
  91 /*------------------------------------------------------------------------------
  92  * Context: process
  93  */
  94 static ssize_t oz_cdev_read(struct file *filp, char __user *buf, size_t count,
  95                 loff_t *fpos)
  96 {
  97         int n;
  98         int ix;
  99
 100         struct oz_pd *pd;
 101         struct oz_serial_ctx *ctx;
 102
 103         spin_lock_bh(&g_cdev.lock);
 104         pd = g_cdev.active_pd;
 105         if (pd)
 106                 oz_pd_get(pd);
 107         spin_unlock_bh(&g_cdev.lock);
 108         if (pd == NULL)
 109                 return -1;
 110         ctx = oz_cdev_claim_ctx(pd);
 111         if (ctx == NULL)
 112                 goto out2;
 113         n = ctx->rd_in - ctx->rd_out;
 114         if (n < 0)
 115                 n += OZ_RD_BUF_SZ;
 116         if (count > n)
 117                 count = n;
 118         ix = ctx->rd_out;
 119         n = OZ_RD_BUF_SZ - ix;
 120         if (n > count)
 121                 n = count;
 122         if (copy_to_user(buf, &ctx->rd_buf[ix], n)) {
 123                 count = 0;
 124                 goto out1;
 125         }
 126         ix += n;
 127         if (ix == OZ_RD_BUF_SZ)
 128                 ix = 0;
 129         if (n < count) {
 130                 if (copy_to_user(&buf[n], ctx->rd_buf, count-n)) {
 131                         count = 0;
 132                         goto out1;
 133                 }
 134                 ix = count-n;
 135         }
 136         ctx->rd_out = ix;
 137 out1:
 138         oz_cdev_release_ctx(ctx);
 139 out2:
 140         oz_pd_put(pd);
 141         return count;
 142 }
 143 /*------------------------------------------------------------------------------
 144  * Context: process
 145  */
 146 static ssize_t oz_cdev_write(struct file *filp, const char __user *buf,
 147                 size_t count, loff_t *fpos)
 148 {
 149         struct oz_pd *pd;
 150         struct oz_elt_buf *eb;
 151         struct oz_elt_info *ei;
 152         struct oz_elt *elt;
 153         struct oz_app_hdr *app_hdr;
 154         struct oz_serial_ctx *ctx;
 155
 156         spin_lock_bh(&g_cdev.lock);
 157         pd = g_cdev.active_pd;
 158         if (pd)
 159                 oz_pd_get(pd);
 160         spin_unlock_bh(&g_cdev.lock);
 161         if (pd == NULL)
 162                 return -1;
 163         eb = &pd->elt_buff;
 164         ei = oz_elt_info_alloc(eb);
 165         if (ei == NULL) {
 166                 count = 0;
 167                 goto out;
 168         }
 169         elt = (struct oz_elt *)ei->data;
 170         app_hdr = (struct oz_app_hdr *)(elt+1);
 171         elt->length = sizeof(struct oz_app_hdr) + count;
 172         elt->type = OZ_ELT_APP_DATA;
 173         ei->app_id = OZ_APPID_SERIAL;
 174         ei->length = elt->length + sizeof(struct oz_elt);
 175         app_hdr->app_id = OZ_APPID_SERIAL;
 176         if (copy_from_user(app_hdr+1, buf, count))
 177                 goto out;
 178         spin_lock_bh(&pd->app_lock[OZ_APPID_USB-1]);
 179         ctx = (struct oz_serial_ctx *)pd->app_ctx[OZ_APPID_SERIAL-1];
 180         if (ctx) {
 181                 app_hdr->elt_seq_num = ctx->tx_seq_num++;
 182                 if (ctx->tx_seq_num == 0)
 183                         ctx->tx_seq_num = 1;
 184                 spin_lock(&eb->lock);
 185                 if (oz_queue_elt_info(eb, 0, 0, ei) == 0)
 186                         ei = NULL;
 187                 spin_unlock(&eb->lock);
 188         }
 189         spin_unlock_bh(&pd->app_lock[OZ_APPID_USB-1]);
 190 out:
 191         if (ei) {
 192                 count = 0;
 193                 spin_lock_bh(&eb->lock);
 194                 oz_elt_info_free(eb, ei);
 195                 spin_unlock_bh(&eb->lock);
 196         }
 197         oz_pd_put(pd);
 198         return count;
 199 }
 200 /*------------------------------------------------------------------------------
 201  * Context: process
 202  */
 203 static int oz_set_active_pd(const u8 *addr)
 204 {
 205         int rc = 0;
 206         struct oz_pd *pd;
 207         struct oz_pd *old_pd;
 208         pd = oz_pd_find(addr);
 209         if (pd) {
 210                 spin_lock_bh(&g_cdev.lock);
 211                 memcpy(g_cdev.active_addr, addr, ETH_ALEN);
 212                 old_pd = g_cdev.active_pd;
 213                 g_cdev.active_pd = pd;
 214                 spin_unlock_bh(&g_cdev.lock);
 215                 if (old_pd)
 216                         oz_pd_put(old_pd);
 217         } else {
 218                 if (is_zero_ether_addr(addr)) {
 219                         spin_lock_bh(&g_cdev.lock);
 220                         pd = g_cdev.active_pd;
 221                         g_cdev.active_pd = NULL;
 222                         memset(g_cdev.active_addr, 0,
 223                                 sizeof(g_cdev.active_addr));
 224                         spin_unlock_bh(&g_cdev.lock);
 225                         if (pd)
 226                                 oz_pd_put(pd);
 227                 } else {
 228                         rc = -1;
 229                 }
 230         }
 231         return rc;
 232 }
 233 /*------------------------------------------------------------------------------
 234  * Context: process
 235  */
 236 static long oz_cdev_ioctl(struct file *filp, unsigned int cmd,
 237                           unsigned long arg)
 238 {
 239         int rc = 0;
 240         if (_IOC_TYPE(cmd) != OZ_IOCTL_MAGIC)
 241                 return -ENOTTY;
 242         if (_IOC_NR(cmd) > OZ_IOCTL_MAX)
 243                 return -ENOTTY;
 244         if (_IOC_DIR(cmd) & _IOC_READ)
 245                 rc = !access_ok(VERIFY_WRITE, (void __user *)arg,
 246                         _IOC_SIZE(cmd));
 247         else if (_IOC_DIR(cmd) & _IOC_WRITE)
 248                 rc = !access_ok(VERIFY_READ, (void __user *)arg,
 249                         _IOC_SIZE(cmd));
 250         if (rc)
 251                 return -EFAULT;
 252         switch (cmd) {
 253         case OZ_IOCTL_GET_PD_LIST: {
 254                         struct oz_pd_list list;
 255                         oz_trace("OZ_IOCTL_GET_PD_LIST\n");
 256                         memset(&list, 0, sizeof(list));
 257                         list.count = oz_get_pd_list(list.addr, OZ_MAX_PDS);
 258                         if (copy_to_user((void __user *)arg, &list,
 259                                 sizeof(list)))
 260                                 return -EFAULT;
 261                 }
 262                 break;
 263         case OZ_IOCTL_SET_ACTIVE_PD: {
 264                         u8 addr[ETH_ALEN];
 265                         oz_trace("OZ_IOCTL_SET_ACTIVE_PD\n");
 266                         if (copy_from_user(addr, (void __user *)arg, ETH_ALEN))
 267                                 return -EFAULT;
 268                         rc = oz_set_active_pd(addr);
 269                 }
 270                 break;
 271         case OZ_IOCTL_GET_ACTIVE_PD: {
 272                         u8 addr[ETH_ALEN];
 273                         oz_trace("OZ_IOCTL_GET_ACTIVE_PD\n");
 274                         spin_lock_bh(&g_cdev.lock);
 275                         memcpy(addr, g_cdev.active_addr, ETH_ALEN);
 276                         spin_unlock_bh(&g_cdev.lock);
 277                         if (copy_to_user((void __user *)arg, addr, ETH_ALEN))
 278                                 return -EFAULT;
 279                 }
 280                 break;
 281         case OZ_IOCTL_ADD_BINDING:
 282         case OZ_IOCTL_REMOVE_BINDING: {
 283                         struct oz_binding_info b;
 284                         if (copy_from_user(&b, (void __user *)arg,
 285                                 sizeof(struct oz_binding_info))) {
 286                                 return -EFAULT;
 287                         }
 288                         /* Make sure name is null terminated. */
 289                         b.name[OZ_MAX_BINDING_LEN-1] = 0;
 290                         if (cmd == OZ_IOCTL_ADD_BINDING)
 291                                 oz_binding_add(b.name);
 292                         else
 293                                 oz_binding_remove(b.name);
 294                 }
 295                 break;
 296         }
 297         return rc;
 298 }
 299 /*------------------------------------------------------------------------------
 300  * Context: process
 301  */
 302 static unsigned int oz_cdev_poll(struct file *filp, poll_table *wait)
 303 {
 304         unsigned int ret = 0;
 305         struct oz_cdev *dev = filp->private_data;
 306         oz_trace("Poll called wait = %p\n", wait);
 307         spin_lock_bh(&dev->lock);
 308         if (dev->active_pd) {
 309                 struct oz_serial_ctx *ctx = oz_cdev_claim_ctx(dev->active_pd);
 310                 if (ctx) {
 311                         if (ctx->rd_in != ctx->rd_out)
 312                                 ret |= POLLIN | POLLRDNORM;
 313                         oz_cdev_release_ctx(ctx);
 314                 }
 315         }
 316         spin_unlock_bh(&dev->lock);
 317         if (wait)
 318                 poll_wait(filp, &dev->rdq, wait);
 319         return ret;
 320 }
 321 /*------------------------------------------------------------------------------
 322  */
 323 static const struct file_operations oz_fops = {
 324         .owner =        THIS_MODULE,
 325         .open =         oz_cdev_open,
 326         .release =      oz_cdev_release,
 327         .read =         oz_cdev_read,
 328         .write =        oz_cdev_write,
 329         .unlocked_ioctl = oz_cdev_ioctl,
 330         .poll =         oz_cdev_poll
 331 };
 332 /*------------------------------------------------------------------------------
 333  * Context: process
 334  */
 335 int oz_cdev_register(void)
 336 {
 337         int err;
 338         struct device *dev;
 339         memset(&g_cdev, 0, sizeof(g_cdev));
 340         err = alloc_chrdev_region(&g_cdev.devnum, 0, 1, "ozwpan");
 341         if (err < 0)
 342                 goto out3;
 343         oz_trace("Alloc dev number %d:%d\n", MAJOR(g_cdev.devnum),
 344                         MINOR(g_cdev.devnum));
 345         cdev_init(&g_cdev.cdev, &oz_fops);
 346         g_cdev.cdev.owner = THIS_MODULE;
 347         g_cdev.cdev.ops = &oz_fops;
 348         spin_lock_init(&g_cdev.lock);
 349         init_waitqueue_head(&g_cdev.rdq);
 350         err = cdev_add(&g_cdev.cdev, g_cdev.devnum, 1);
 351         if (err < 0) {
 352                 oz_trace("Failed to add cdev\n");
 353                 goto out2;
 354         }
 355         g_oz_class = class_create(THIS_MODULE, "ozmo_wpan");
 356         if (IS_ERR(g_oz_class)) {
 357                 oz_trace("Failed to register ozmo_wpan class\n");
 358                 goto out1;
 359         }
 360         dev = device_create(g_oz_class, NULL, g_cdev.devnum, NULL, "ozwpan");
 361         if (IS_ERR(dev)) {
 362                 oz_trace("Failed to create sysfs entry for cdev\n");
 363                 goto out1;
 364         }
 365         return 0;
 366 out1:
 367         cdev_del(&g_cdev.cdev);
 368 out2:
 369         unregister_chrdev_region(g_cdev.devnum, 1);
 370 out3:
 371         return err;
 372 }
 373 /*------------------------------------------------------------------------------
 374  * Context: process
 375  */
 376 int oz_cdev_deregister(void)
 377 {
 378         cdev_del(&g_cdev.cdev);
 379         unregister_chrdev_region(g_cdev.devnum, 1);
 380         if (g_oz_class) {
 381                 device_destroy(g_oz_class, g_cdev.devnum);
 382                 class_destroy(g_oz_class);
 383         }
 384         return 0;
 385 }
 386 /*------------------------------------------------------------------------------
 387  * Context: process
 388  */
 389 int oz_cdev_init(void)
 390 {
 391         oz_event_log(OZ_EVT_SERVICE, 1, OZ_APPID_SERIAL, NULL, 0);
 392         oz_app_enable(OZ_APPID_SERIAL, 1);
 393         return 0;
 394 }
 395 /*------------------------------------------------------------------------------
 396  * Context: process
 397  */
 398 void oz_cdev_term(void)
 399 {
 400         oz_event_log(OZ_EVT_SERVICE, 2, OZ_APPID_SERIAL, NULL, 0);
 401         oz_app_enable(OZ_APPID_SERIAL, 0);
 402 }
 403 /*------------------------------------------------------------------------------
 404  * Context: softirq-serialized
 405  */
 406 int oz_cdev_start(struct oz_pd *pd, int resume)
 407 {
 408         struct oz_serial_ctx *ctx;
 409         struct oz_serial_ctx *old_ctx;
 410         oz_event_log(OZ_EVT_SERVICE, 3, OZ_APPID_SERIAL, NULL, resume);
 411         if (resume) {
 412                 oz_trace("Serial service resumed.\n");
 413                 return 0;
 414         }
 415         ctx = kzalloc(sizeof(struct oz_serial_ctx), GFP_ATOMIC);
 416         if (ctx == NULL)
 417                 return -ENOMEM;
 418         atomic_set(&ctx->ref_count, 1);
 419         ctx->tx_seq_num = 1;
 420         spin_lock_bh(&pd->app_lock[OZ_APPID_SERIAL-1]);
 421         old_ctx = pd->app_ctx[OZ_APPID_SERIAL-1];
 422         if (old_ctx) {
 423                 spin_unlock_bh(&pd->app_lock[OZ_APPID_SERIAL-1]);
 424                 kfree(ctx);
 425         } else {
 426                 pd->app_ctx[OZ_APPID_SERIAL-1] = ctx;
 427                 spin_unlock_bh(&pd->app_lock[OZ_APPID_SERIAL-1]);
 428         }
 429         spin_lock(&g_cdev.lock);
 430         if ((g_cdev.active_pd == NULL) &&
 431                 (memcmp(pd->mac_addr, g_cdev.active_addr, ETH_ALEN) == 0)) {
 432                 oz_pd_get(pd);
 433                 g_cdev.active_pd = pd;
 434                 oz_trace("Active PD arrived.\n");
 435         }
 436         spin_unlock(&g_cdev.lock);
 437         oz_trace("Serial service started.\n");
 438         return 0;
 439 }
 440 /*------------------------------------------------------------------------------
 441  * Context: softirq or process
 442  */
 443 void oz_cdev_stop(struct oz_pd *pd, int pause)
 444 {
 445         struct oz_serial_ctx *ctx;
 446         oz_event_log(OZ_EVT_SERVICE, 4, OZ_APPID_SERIAL, NULL, pause);
 447         if (pause) {
 448                 oz_trace("Serial service paused.\n");
 449                 return;
 450         }
 451         spin_lock_bh(&pd->app_lock[OZ_APPID_SERIAL-1]);
 452         ctx = (struct oz_serial_ctx *)pd->app_ctx[OZ_APPID_SERIAL-1];
 453         pd->app_ctx[OZ_APPID_SERIAL-1] = NULL;
 454         spin_unlock_bh(&pd->app_lock[OZ_APPID_SERIAL-1]);
 455         if (ctx)
 456                 oz_cdev_release_ctx(ctx);
 457         spin_lock(&g_cdev.lock);
 458         if (pd == g_cdev.active_pd)
 459                 g_cdev.active_pd = NULL;
 460         else
 461                 pd = NULL;
 462         spin_unlock(&g_cdev.lock);
 463         if (pd) {
 464                 oz_pd_put(pd);
 465                 oz_trace("Active PD departed.\n");
 466         }
 467         oz_trace("Serial service stopped.\n");
 468 }
 469 /*------------------------------------------------------------------------------
 470  * Context: softirq-serialized
 471  */
 472 void oz_cdev_rx(struct oz_pd *pd, struct oz_elt *elt)
 473 {
 474         struct oz_serial_ctx *ctx;
 475         struct oz_app_hdr *app_hdr;
 476         u8 *data;
 477         int len;
 478         int space;
 479         int copy_sz;
 480         int ix;
 481
 482         ctx = oz_cdev_claim_ctx(pd);
 483         if (ctx == NULL) {
 484                 oz_trace("Cannot claim serial context.\n");
 485                 return;
 486         }
 487
 488         app_hdr = (struct oz_app_hdr *)(elt+1);
 489         /* If sequence number is non-zero then check it is not a duplicate.
 490          */
 491         if (app_hdr->elt_seq_num != 0) {
 492                 if (((ctx->rx_seq_num - app_hdr->elt_seq_num) & 0x80) == 0) {
 493                         /* Reject duplicate element. */
 494                         oz_trace("Duplicate element:%02x %02x\n",
 495                                 app_hdr->elt_seq_num, ctx->rx_seq_num);
 496                         goto out;
 497                 }
 498         }
 499         ctx->rx_seq_num = app_hdr->elt_seq_num;
 500         len = elt->length - sizeof(struct oz_app_hdr);
 501         data = ((u8 *)(elt+1)) + sizeof(struct oz_app_hdr);
 502         if (len <= 0)
 503                 goto out;
 504         space = ctx->rd_out - ctx->rd_in - 1;
 505         if (space < 0)
 506                 space += OZ_RD_BUF_SZ;
 507         if (len > space) {
 508                 oz_trace("Not enough space:%d %d\n", len, space);
 509                 len = space;
 510         }
 511         ix = ctx->rd_in;
 512         copy_sz = OZ_RD_BUF_SZ - ix;
 513         if (copy_sz > len)
 514                 copy_sz = len;
 515         memcpy(&ctx->rd_buf[ix], data, copy_sz);
 516         len -= copy_sz;
 517         ix += copy_sz;
 518         if (ix == OZ_RD_BUF_SZ)
 519                 ix = 0;
 520         if (len) {
 521                 memcpy(ctx->rd_buf, data+copy_sz, len);
 522                 ix = len;
 523         }
 524         ctx->rd_in = ix;
 525         wake_up(&g_cdev.rdq);
 526 out:
 527         oz_cdev_release_ctx(ctx);
 528 }