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