Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* generic HDLC line discipline for Linux |
| 2 | * |
| 3 | * Written by Paul Fulghum paulkf@microgate.com |
| 4 | * for Microgate Corporation |
| 5 | * |
| 6 | * Microgate and SyncLink are registered trademarks of Microgate Corporation |
| 7 | * |
| 8 | * Adapted from ppp.c, written by Michael Callahan <callahan@maths.ox.ac.uk>, |
| 9 | * Al Longyear <longyear@netcom.com>, |
| 10 | * Paul Mackerras <Paul.Mackerras@cs.anu.edu.au> |
| 11 | * |
| 12 | * Original release 01/11/99 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 13 | * |
| 14 | * This code is released under the GNU General Public License (GPL) |
| 15 | * |
| 16 | * This module implements the tty line discipline N_HDLC for use with |
| 17 | * tty device drivers that support bit-synchronous HDLC communications. |
| 18 | * |
| 19 | * All HDLC data is frame oriented which means: |
| 20 | * |
| 21 | * 1. tty write calls represent one complete transmit frame of data |
| 22 | * The device driver should accept the complete frame or none of |
| 23 | * the frame (busy) in the write method. Each write call should have |
| 24 | * a byte count in the range of 2-65535 bytes (2 is min HDLC frame |
| 25 | * with 1 addr byte and 1 ctrl byte). The max byte count of 65535 |
| 26 | * should include any crc bytes required. For example, when using |
| 27 | * CCITT CRC32, 4 crc bytes are required, so the maximum size frame |
| 28 | * the application may transmit is limited to 65531 bytes. For CCITT |
| 29 | * CRC16, the maximum application frame size would be 65533. |
| 30 | * |
| 31 | * |
| 32 | * 2. receive callbacks from the device driver represents |
| 33 | * one received frame. The device driver should bypass |
| 34 | * the tty flip buffer and call the line discipline receive |
| 35 | * callback directly to avoid fragmenting or concatenating |
| 36 | * multiple frames into a single receive callback. |
| 37 | * |
| 38 | * The HDLC line discipline queues the receive frames in separate |
| 39 | * buffers so complete receive frames can be returned by the |
| 40 | * tty read calls. |
| 41 | * |
| 42 | * 3. tty read calls returns an entire frame of data or nothing. |
| 43 | * |
| 44 | * 4. all send and receive data is considered raw. No processing |
| 45 | * or translation is performed by the line discipline, regardless |
| 46 | * of the tty flags |
| 47 | * |
| 48 | * 5. When line discipline is queried for the amount of receive |
| 49 | * data available (FIOC), 0 is returned if no data available, |
| 50 | * otherwise the count of the next available frame is returned. |
| 51 | * (instead of the sum of all received frame counts). |
| 52 | * |
| 53 | * These conventions allow the standard tty programming interface |
| 54 | * to be used for synchronous HDLC applications when used with |
| 55 | * this line discipline (or another line discipline that is frame |
| 56 | * oriented such as N_PPP). |
| 57 | * |
| 58 | * The SyncLink driver (synclink.c) implements both asynchronous |
| 59 | * (using standard line discipline N_TTY) and synchronous HDLC |
| 60 | * (using N_HDLC) communications, with the latter using the above |
| 61 | * conventions. |
| 62 | * |
| 63 | * This implementation is very basic and does not maintain |
| 64 | * any statistics. The main point is to enforce the raw data |
| 65 | * and frame orientation of HDLC communications. |
| 66 | * |
| 67 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED |
| 68 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 69 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
| 70 | * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, |
| 71 | * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
| 72 | * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR |
| 73 | * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 74 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
| 75 | * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| 76 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED |
| 77 | * OF THE POSSIBILITY OF SUCH DAMAGE. |
| 78 | */ |
| 79 | |
| 80 | #define HDLC_MAGIC 0x239e |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 81 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 82 | #include <linux/module.h> |
| 83 | #include <linux/init.h> |
| 84 | #include <linux/kernel.h> |
| 85 | #include <linux/sched.h> |
| 86 | #include <linux/types.h> |
| 87 | #include <linux/fcntl.h> |
| 88 | #include <linux/interrupt.h> |
| 89 | #include <linux/ptrace.h> |
| 90 | |
| 91 | #undef VERSION |
| 92 | #define VERSION(major,minor,patch) (((((major)<<8)+(minor))<<8)+(patch)) |
| 93 | |
| 94 | #include <linux/poll.h> |
| 95 | #include <linux/in.h> |
| 96 | #include <linux/ioctl.h> |
| 97 | #include <linux/slab.h> |
| 98 | #include <linux/tty.h> |
| 99 | #include <linux/errno.h> |
| 100 | #include <linux/string.h> /* used in new tty drivers */ |
| 101 | #include <linux/signal.h> /* used in new tty drivers */ |
| 102 | #include <linux/if.h> |
| 103 | #include <linux/bitops.h> |
| 104 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 105 | #include <asm/termios.h> |
| 106 | #include <asm/uaccess.h> |
| 107 | |
| 108 | /* |
| 109 | * Buffers for individual HDLC frames |
| 110 | */ |
| 111 | #define MAX_HDLC_FRAME_SIZE 65535 |
| 112 | #define DEFAULT_RX_BUF_COUNT 10 |
| 113 | #define MAX_RX_BUF_COUNT 60 |
Paul Fulghum | be10eb7 | 2009-06-22 18:42:56 +0100 | [diff] [blame] | 114 | #define DEFAULT_TX_BUF_COUNT 3 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 115 | |
| 116 | struct n_hdlc_buf { |
| 117 | struct n_hdlc_buf *link; |
| 118 | int count; |
| 119 | char buf[1]; |
| 120 | }; |
| 121 | |
| 122 | #define N_HDLC_BUF_SIZE (sizeof(struct n_hdlc_buf) + maxframe) |
| 123 | |
| 124 | struct n_hdlc_buf_list { |
| 125 | struct n_hdlc_buf *head; |
| 126 | struct n_hdlc_buf *tail; |
| 127 | int count; |
| 128 | spinlock_t spinlock; |
| 129 | }; |
| 130 | |
| 131 | /** |
| 132 | * struct n_hdlc - per device instance data structure |
| 133 | * @magic - magic value for structure |
| 134 | * @flags - miscellaneous control flags |
| 135 | * @tty - ptr to TTY structure |
| 136 | * @backup_tty - TTY to use if tty gets closed |
| 137 | * @tbusy - reentrancy flag for tx wakeup code |
| 138 | * @woke_up - FIXME: describe this field |
| 139 | * @tbuf - currently transmitting tx buffer |
| 140 | * @tx_buf_list - list of pending transmit frame buffers |
| 141 | * @rx_buf_list - list of received frame buffers |
| 142 | * @tx_free_buf_list - list unused transmit frame buffers |
| 143 | * @rx_free_buf_list - list unused received frame buffers |
| 144 | */ |
| 145 | struct n_hdlc { |
| 146 | int magic; |
| 147 | __u32 flags; |
| 148 | struct tty_struct *tty; |
| 149 | struct tty_struct *backup_tty; |
| 150 | int tbusy; |
| 151 | int woke_up; |
| 152 | struct n_hdlc_buf *tbuf; |
| 153 | struct n_hdlc_buf_list tx_buf_list; |
| 154 | struct n_hdlc_buf_list rx_buf_list; |
| 155 | struct n_hdlc_buf_list tx_free_buf_list; |
| 156 | struct n_hdlc_buf_list rx_free_buf_list; |
| 157 | }; |
| 158 | |
| 159 | /* |
| 160 | * HDLC buffer list manipulation functions |
| 161 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 162 | static void n_hdlc_buf_put(struct n_hdlc_buf_list *list, |
| 163 | struct n_hdlc_buf *buf); |
| 164 | static struct n_hdlc_buf *n_hdlc_buf_get(struct n_hdlc_buf_list *list); |
| 165 | |
| 166 | /* Local functions */ |
| 167 | |
| 168 | static struct n_hdlc *n_hdlc_alloc (void); |
| 169 | |
| 170 | /* debug level can be set by insmod for debugging purposes */ |
| 171 | #define DEBUG_LEVEL_INFO 1 |
| 172 | static int debuglevel; |
| 173 | |
| 174 | /* max frame size for memory allocations */ |
| 175 | static int maxframe = 4096; |
| 176 | |
| 177 | /* TTY callbacks */ |
| 178 | |
| 179 | static ssize_t n_hdlc_tty_read(struct tty_struct *tty, struct file *file, |
| 180 | __u8 __user *buf, size_t nr); |
| 181 | static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file, |
| 182 | const unsigned char *buf, size_t nr); |
| 183 | static int n_hdlc_tty_ioctl(struct tty_struct *tty, struct file *file, |
| 184 | unsigned int cmd, unsigned long arg); |
| 185 | static unsigned int n_hdlc_tty_poll(struct tty_struct *tty, struct file *filp, |
| 186 | poll_table *wait); |
| 187 | static int n_hdlc_tty_open(struct tty_struct *tty); |
| 188 | static void n_hdlc_tty_close(struct tty_struct *tty); |
Linus Torvalds | 55db4c6 | 2011-06-04 06:33:24 +0900 | [diff] [blame] | 189 | static void n_hdlc_tty_receive(struct tty_struct *tty, const __u8 *cp, |
| 190 | char *fp, int count); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 191 | static void n_hdlc_tty_wakeup(struct tty_struct *tty); |
| 192 | |
| 193 | #define bset(p,b) ((p)[(b) >> 5] |= (1 << ((b) & 0x1f))) |
| 194 | |
| 195 | #define tty2n_hdlc(tty) ((struct n_hdlc *) ((tty)->disc_data)) |
| 196 | #define n_hdlc2tty(n_hdlc) ((n_hdlc)->tty) |
| 197 | |
Paul Fulghum | be10eb7 | 2009-06-22 18:42:56 +0100 | [diff] [blame] | 198 | static void flush_rx_queue(struct tty_struct *tty) |
| 199 | { |
| 200 | struct n_hdlc *n_hdlc = tty2n_hdlc(tty); |
| 201 | struct n_hdlc_buf *buf; |
| 202 | |
| 203 | while ((buf = n_hdlc_buf_get(&n_hdlc->rx_buf_list))) |
| 204 | n_hdlc_buf_put(&n_hdlc->rx_free_buf_list, buf); |
| 205 | } |
| 206 | |
| 207 | static void flush_tx_queue(struct tty_struct *tty) |
| 208 | { |
| 209 | struct n_hdlc *n_hdlc = tty2n_hdlc(tty); |
| 210 | struct n_hdlc_buf *buf; |
| 211 | unsigned long flags; |
| 212 | |
| 213 | while ((buf = n_hdlc_buf_get(&n_hdlc->tx_buf_list))) |
| 214 | n_hdlc_buf_put(&n_hdlc->tx_free_buf_list, buf); |
| 215 | spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock, flags); |
| 216 | if (n_hdlc->tbuf) { |
| 217 | n_hdlc_buf_put(&n_hdlc->tx_free_buf_list, n_hdlc->tbuf); |
| 218 | n_hdlc->tbuf = NULL; |
| 219 | } |
| 220 | spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock, flags); |
| 221 | } |
| 222 | |
Alan Cox | a352def | 2008-07-16 21:53:12 +0100 | [diff] [blame] | 223 | static struct tty_ldisc_ops n_hdlc_ldisc = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 224 | .owner = THIS_MODULE, |
| 225 | .magic = TTY_LDISC_MAGIC, |
| 226 | .name = "hdlc", |
| 227 | .open = n_hdlc_tty_open, |
| 228 | .close = n_hdlc_tty_close, |
| 229 | .read = n_hdlc_tty_read, |
| 230 | .write = n_hdlc_tty_write, |
| 231 | .ioctl = n_hdlc_tty_ioctl, |
| 232 | .poll = n_hdlc_tty_poll, |
| 233 | .receive_buf = n_hdlc_tty_receive, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 234 | .write_wakeup = n_hdlc_tty_wakeup, |
Paul Fulghum | be10eb7 | 2009-06-22 18:42:56 +0100 | [diff] [blame] | 235 | .flush_buffer = flush_rx_queue, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 236 | }; |
| 237 | |
| 238 | /** |
| 239 | * n_hdlc_release - release an n_hdlc per device line discipline info structure |
| 240 | * @n_hdlc - per device line discipline info structure |
| 241 | */ |
| 242 | static void n_hdlc_release(struct n_hdlc *n_hdlc) |
| 243 | { |
| 244 | struct tty_struct *tty = n_hdlc2tty (n_hdlc); |
| 245 | struct n_hdlc_buf *buf; |
| 246 | |
| 247 | if (debuglevel >= DEBUG_LEVEL_INFO) |
| 248 | printk("%s(%d)n_hdlc_release() called\n",__FILE__,__LINE__); |
| 249 | |
| 250 | /* Ensure that the n_hdlcd process is not hanging on select()/poll() */ |
| 251 | wake_up_interruptible (&tty->read_wait); |
| 252 | wake_up_interruptible (&tty->write_wait); |
| 253 | |
Adrian Bunk | 827afdf | 2007-10-16 23:29:25 -0700 | [diff] [blame] | 254 | if (tty->disc_data == n_hdlc) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 255 | tty->disc_data = NULL; /* Break the tty->n_hdlc link */ |
| 256 | |
| 257 | /* Release transmit and receive buffers */ |
| 258 | for(;;) { |
| 259 | buf = n_hdlc_buf_get(&n_hdlc->rx_free_buf_list); |
| 260 | if (buf) { |
| 261 | kfree(buf); |
| 262 | } else |
| 263 | break; |
| 264 | } |
| 265 | for(;;) { |
| 266 | buf = n_hdlc_buf_get(&n_hdlc->tx_free_buf_list); |
| 267 | if (buf) { |
| 268 | kfree(buf); |
| 269 | } else |
| 270 | break; |
| 271 | } |
| 272 | for(;;) { |
| 273 | buf = n_hdlc_buf_get(&n_hdlc->rx_buf_list); |
| 274 | if (buf) { |
| 275 | kfree(buf); |
| 276 | } else |
| 277 | break; |
| 278 | } |
| 279 | for(;;) { |
| 280 | buf = n_hdlc_buf_get(&n_hdlc->tx_buf_list); |
| 281 | if (buf) { |
| 282 | kfree(buf); |
| 283 | } else |
| 284 | break; |
| 285 | } |
Jesper Juhl | 735d566 | 2005-11-07 01:01:29 -0800 | [diff] [blame] | 286 | kfree(n_hdlc->tbuf); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 287 | kfree(n_hdlc); |
| 288 | |
| 289 | } /* end of n_hdlc_release() */ |
| 290 | |
| 291 | /** |
| 292 | * n_hdlc_tty_close - line discipline close |
| 293 | * @tty - pointer to tty info structure |
| 294 | * |
| 295 | * Called when the line discipline is changed to something |
| 296 | * else, the tty is closed, or the tty detects a hangup. |
| 297 | */ |
| 298 | static void n_hdlc_tty_close(struct tty_struct *tty) |
| 299 | { |
| 300 | struct n_hdlc *n_hdlc = tty2n_hdlc (tty); |
| 301 | |
| 302 | if (debuglevel >= DEBUG_LEVEL_INFO) |
| 303 | printk("%s(%d)n_hdlc_tty_close() called\n",__FILE__,__LINE__); |
| 304 | |
| 305 | if (n_hdlc != NULL) { |
| 306 | if (n_hdlc->magic != HDLC_MAGIC) { |
| 307 | printk (KERN_WARNING"n_hdlc: trying to close unopened tty!\n"); |
| 308 | return; |
| 309 | } |
| 310 | #if defined(TTY_NO_WRITE_SPLIT) |
| 311 | clear_bit(TTY_NO_WRITE_SPLIT,&tty->flags); |
| 312 | #endif |
| 313 | tty->disc_data = NULL; |
| 314 | if (tty == n_hdlc->backup_tty) |
| 315 | n_hdlc->backup_tty = NULL; |
| 316 | if (tty != n_hdlc->tty) |
| 317 | return; |
| 318 | if (n_hdlc->backup_tty) { |
| 319 | n_hdlc->tty = n_hdlc->backup_tty; |
| 320 | } else { |
| 321 | n_hdlc_release (n_hdlc); |
| 322 | } |
| 323 | } |
| 324 | |
| 325 | if (debuglevel >= DEBUG_LEVEL_INFO) |
| 326 | printk("%s(%d)n_hdlc_tty_close() success\n",__FILE__,__LINE__); |
| 327 | |
| 328 | } /* end of n_hdlc_tty_close() */ |
| 329 | |
| 330 | /** |
| 331 | * n_hdlc_tty_open - called when line discipline changed to n_hdlc |
| 332 | * @tty - pointer to tty info structure |
| 333 | * |
| 334 | * Returns 0 if success, otherwise error code |
| 335 | */ |
| 336 | static int n_hdlc_tty_open (struct tty_struct *tty) |
| 337 | { |
| 338 | struct n_hdlc *n_hdlc = tty2n_hdlc (tty); |
| 339 | |
| 340 | if (debuglevel >= DEBUG_LEVEL_INFO) |
| 341 | printk("%s(%d)n_hdlc_tty_open() called (device=%s)\n", |
| 342 | __FILE__,__LINE__, |
| 343 | tty->name); |
| 344 | |
| 345 | /* There should not be an existing table for this slot. */ |
| 346 | if (n_hdlc) { |
| 347 | printk (KERN_ERR"n_hdlc_tty_open:tty already associated!\n" ); |
| 348 | return -EEXIST; |
| 349 | } |
| 350 | |
| 351 | n_hdlc = n_hdlc_alloc(); |
| 352 | if (!n_hdlc) { |
| 353 | printk (KERN_ERR "n_hdlc_alloc failed\n"); |
| 354 | return -ENFILE; |
| 355 | } |
| 356 | |
| 357 | tty->disc_data = n_hdlc; |
| 358 | n_hdlc->tty = tty; |
Alan Cox | 33f0f88 | 2006-01-09 20:54:13 -0800 | [diff] [blame] | 359 | tty->receive_room = 65536; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 360 | |
| 361 | #if defined(TTY_NO_WRITE_SPLIT) |
| 362 | /* change tty_io write() to not split large writes into 8K chunks */ |
| 363 | set_bit(TTY_NO_WRITE_SPLIT,&tty->flags); |
| 364 | #endif |
| 365 | |
Paul Fulghum | be10eb7 | 2009-06-22 18:42:56 +0100 | [diff] [blame] | 366 | /* flush receive data from driver */ |
Alan Cox | f34d7a5 | 2008-04-30 00:54:13 -0700 | [diff] [blame] | 367 | tty_driver_flush_buffer(tty); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 368 | |
| 369 | if (debuglevel >= DEBUG_LEVEL_INFO) |
| 370 | printk("%s(%d)n_hdlc_tty_open() success\n",__FILE__,__LINE__); |
| 371 | |
| 372 | return 0; |
| 373 | |
| 374 | } /* end of n_tty_hdlc_open() */ |
| 375 | |
| 376 | /** |
| 377 | * n_hdlc_send_frames - send frames on pending send buffer list |
| 378 | * @n_hdlc - pointer to ldisc instance data |
| 379 | * @tty - pointer to tty instance data |
| 380 | * |
| 381 | * Send frames on pending send buffer list until the driver does not accept a |
| 382 | * frame (busy) this function is called after adding a frame to the send buffer |
| 383 | * list and by the tty wakeup callback. |
| 384 | */ |
| 385 | static void n_hdlc_send_frames(struct n_hdlc *n_hdlc, struct tty_struct *tty) |
| 386 | { |
| 387 | register int actual; |
| 388 | unsigned long flags; |
| 389 | struct n_hdlc_buf *tbuf; |
| 390 | |
| 391 | if (debuglevel >= DEBUG_LEVEL_INFO) |
| 392 | printk("%s(%d)n_hdlc_send_frames() called\n",__FILE__,__LINE__); |
| 393 | check_again: |
| 394 | |
| 395 | spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock, flags); |
| 396 | if (n_hdlc->tbusy) { |
| 397 | n_hdlc->woke_up = 1; |
| 398 | spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock, flags); |
| 399 | return; |
| 400 | } |
| 401 | n_hdlc->tbusy = 1; |
| 402 | n_hdlc->woke_up = 0; |
| 403 | spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock, flags); |
| 404 | |
| 405 | /* get current transmit buffer or get new transmit */ |
| 406 | /* buffer from list of pending transmit buffers */ |
| 407 | |
| 408 | tbuf = n_hdlc->tbuf; |
| 409 | if (!tbuf) |
| 410 | tbuf = n_hdlc_buf_get(&n_hdlc->tx_buf_list); |
| 411 | |
| 412 | while (tbuf) { |
| 413 | if (debuglevel >= DEBUG_LEVEL_INFO) |
| 414 | printk("%s(%d)sending frame %p, count=%d\n", |
| 415 | __FILE__,__LINE__,tbuf,tbuf->count); |
| 416 | |
| 417 | /* Send the next block of data to device */ |
Ilya Zykov | 7962fce | 2011-11-07 11:32:46 +0400 | [diff] [blame] | 418 | set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); |
Alan Cox | f34d7a5 | 2008-04-30 00:54:13 -0700 | [diff] [blame] | 419 | actual = tty->ops->write(tty, tbuf->buf, tbuf->count); |
Jiri Slaby | b0fed31 | 2007-07-15 23:40:12 -0700 | [diff] [blame] | 420 | |
| 421 | /* rollback was possible and has been done */ |
| 422 | if (actual == -ERESTARTSYS) { |
| 423 | n_hdlc->tbuf = tbuf; |
| 424 | break; |
| 425 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 426 | /* if transmit error, throw frame away by */ |
| 427 | /* pretending it was accepted by driver */ |
| 428 | if (actual < 0) |
| 429 | actual = tbuf->count; |
| 430 | |
| 431 | if (actual == tbuf->count) { |
| 432 | if (debuglevel >= DEBUG_LEVEL_INFO) |
| 433 | printk("%s(%d)frame %p completed\n", |
| 434 | __FILE__,__LINE__,tbuf); |
| 435 | |
| 436 | /* free current transmit buffer */ |
| 437 | n_hdlc_buf_put(&n_hdlc->tx_free_buf_list, tbuf); |
| 438 | |
| 439 | /* this tx buffer is done */ |
| 440 | n_hdlc->tbuf = NULL; |
| 441 | |
| 442 | /* wait up sleeping writers */ |
| 443 | wake_up_interruptible(&tty->write_wait); |
| 444 | |
| 445 | /* get next pending transmit buffer */ |
| 446 | tbuf = n_hdlc_buf_get(&n_hdlc->tx_buf_list); |
| 447 | } else { |
| 448 | if (debuglevel >= DEBUG_LEVEL_INFO) |
| 449 | printk("%s(%d)frame %p pending\n", |
| 450 | __FILE__,__LINE__,tbuf); |
| 451 | |
| 452 | /* buffer not accepted by driver */ |
| 453 | /* set this buffer as pending buffer */ |
| 454 | n_hdlc->tbuf = tbuf; |
| 455 | break; |
| 456 | } |
| 457 | } |
| 458 | |
| 459 | if (!tbuf) |
Ilya Zykov | 7962fce | 2011-11-07 11:32:46 +0400 | [diff] [blame] | 460 | clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 461 | |
| 462 | /* Clear the re-entry flag */ |
| 463 | spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock, flags); |
| 464 | n_hdlc->tbusy = 0; |
| 465 | spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock, flags); |
| 466 | |
| 467 | if (n_hdlc->woke_up) |
| 468 | goto check_again; |
| 469 | |
| 470 | if (debuglevel >= DEBUG_LEVEL_INFO) |
| 471 | printk("%s(%d)n_hdlc_send_frames() exit\n",__FILE__,__LINE__); |
| 472 | |
| 473 | } /* end of n_hdlc_send_frames() */ |
| 474 | |
| 475 | /** |
| 476 | * n_hdlc_tty_wakeup - Callback for transmit wakeup |
| 477 | * @tty - pointer to associated tty instance data |
| 478 | * |
| 479 | * Called when low level device driver can accept more send data. |
| 480 | */ |
| 481 | static void n_hdlc_tty_wakeup(struct tty_struct *tty) |
| 482 | { |
| 483 | struct n_hdlc *n_hdlc = tty2n_hdlc(tty); |
| 484 | |
| 485 | if (debuglevel >= DEBUG_LEVEL_INFO) |
| 486 | printk("%s(%d)n_hdlc_tty_wakeup() called\n",__FILE__,__LINE__); |
| 487 | |
| 488 | if (!n_hdlc) |
| 489 | return; |
| 490 | |
| 491 | if (tty != n_hdlc->tty) { |
Ilya Zykov | 7962fce | 2011-11-07 11:32:46 +0400 | [diff] [blame] | 492 | clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 493 | return; |
| 494 | } |
| 495 | |
| 496 | n_hdlc_send_frames (n_hdlc, tty); |
| 497 | |
| 498 | } /* end of n_hdlc_tty_wakeup() */ |
| 499 | |
| 500 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 501 | * n_hdlc_tty_receive - Called by tty driver when receive data is available |
| 502 | * @tty - pointer to tty instance data |
| 503 | * @data - pointer to received data |
| 504 | * @flags - pointer to flags for data |
| 505 | * @count - count of received data in bytes |
| 506 | * |
| 507 | * Called by tty low level driver when receive data is available. Data is |
| 508 | * interpreted as one HDLC frame. |
| 509 | */ |
Linus Torvalds | 55db4c6 | 2011-06-04 06:33:24 +0900 | [diff] [blame] | 510 | static void n_hdlc_tty_receive(struct tty_struct *tty, const __u8 *data, |
| 511 | char *flags, int count) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 512 | { |
| 513 | register struct n_hdlc *n_hdlc = tty2n_hdlc (tty); |
| 514 | register struct n_hdlc_buf *buf; |
| 515 | |
| 516 | if (debuglevel >= DEBUG_LEVEL_INFO) |
| 517 | printk("%s(%d)n_hdlc_tty_receive() called count=%d\n", |
| 518 | __FILE__,__LINE__, count); |
| 519 | |
| 520 | /* This can happen if stuff comes in on the backup tty */ |
Harvey Harrison | a01e035 | 2008-04-28 16:50:04 -0700 | [diff] [blame] | 521 | if (!n_hdlc || tty != n_hdlc->tty) |
Linus Torvalds | 55db4c6 | 2011-06-04 06:33:24 +0900 | [diff] [blame] | 522 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 523 | |
| 524 | /* verify line is using HDLC discipline */ |
| 525 | if (n_hdlc->magic != HDLC_MAGIC) { |
| 526 | printk("%s(%d) line not using HDLC discipline\n", |
| 527 | __FILE__,__LINE__); |
Linus Torvalds | 55db4c6 | 2011-06-04 06:33:24 +0900 | [diff] [blame] | 528 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 529 | } |
| 530 | |
| 531 | if ( count>maxframe ) { |
| 532 | if (debuglevel >= DEBUG_LEVEL_INFO) |
| 533 | printk("%s(%d) rx count>maxframesize, data discarded\n", |
| 534 | __FILE__,__LINE__); |
Linus Torvalds | 55db4c6 | 2011-06-04 06:33:24 +0900 | [diff] [blame] | 535 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 536 | } |
| 537 | |
| 538 | /* get a free HDLC buffer */ |
| 539 | buf = n_hdlc_buf_get(&n_hdlc->rx_free_buf_list); |
| 540 | if (!buf) { |
| 541 | /* no buffers in free list, attempt to allocate another rx buffer */ |
| 542 | /* unless the maximum count has been reached */ |
| 543 | if (n_hdlc->rx_buf_list.count < MAX_RX_BUF_COUNT) |
| 544 | buf = kmalloc(N_HDLC_BUF_SIZE, GFP_ATOMIC); |
| 545 | } |
| 546 | |
| 547 | if (!buf) { |
| 548 | if (debuglevel >= DEBUG_LEVEL_INFO) |
| 549 | printk("%s(%d) no more rx buffers, data discarded\n", |
| 550 | __FILE__,__LINE__); |
Linus Torvalds | 55db4c6 | 2011-06-04 06:33:24 +0900 | [diff] [blame] | 551 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 552 | } |
| 553 | |
| 554 | /* copy received data to HDLC buffer */ |
| 555 | memcpy(buf->buf,data,count); |
| 556 | buf->count=count; |
| 557 | |
| 558 | /* add HDLC buffer to list of received frames */ |
| 559 | n_hdlc_buf_put(&n_hdlc->rx_buf_list, buf); |
| 560 | |
| 561 | /* wake up any blocked reads and perform async signalling */ |
| 562 | wake_up_interruptible (&tty->read_wait); |
| 563 | if (n_hdlc->tty->fasync != NULL) |
| 564 | kill_fasync (&n_hdlc->tty->fasync, SIGIO, POLL_IN); |
| 565 | |
| 566 | } /* end of n_hdlc_tty_receive() */ |
| 567 | |
| 568 | /** |
Matt Mackall | 4a4efbd | 2006-01-03 13:27:11 +0100 | [diff] [blame] | 569 | * n_hdlc_tty_read - Called to retrieve one frame of data (if available) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 570 | * @tty - pointer to tty instance data |
| 571 | * @file - pointer to open file object |
| 572 | * @buf - pointer to returned data buffer |
| 573 | * @nr - size of returned data buffer |
| 574 | * |
| 575 | * Returns the number of bytes returned or error code. |
| 576 | */ |
| 577 | static ssize_t n_hdlc_tty_read(struct tty_struct *tty, struct file *file, |
| 578 | __u8 __user *buf, size_t nr) |
| 579 | { |
| 580 | struct n_hdlc *n_hdlc = tty2n_hdlc(tty); |
Paul Fulghum | 1035b63 | 2011-01-18 14:03:25 -0800 | [diff] [blame] | 581 | int ret = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 582 | struct n_hdlc_buf *rbuf; |
Paul Fulghum | 1035b63 | 2011-01-18 14:03:25 -0800 | [diff] [blame] | 583 | DECLARE_WAITQUEUE(wait, current); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 584 | |
| 585 | if (debuglevel >= DEBUG_LEVEL_INFO) |
| 586 | printk("%s(%d)n_hdlc_tty_read() called\n",__FILE__,__LINE__); |
| 587 | |
| 588 | /* Validate the pointers */ |
| 589 | if (!n_hdlc) |
| 590 | return -EIO; |
| 591 | |
| 592 | /* verify user access to buffer */ |
| 593 | if (!access_ok(VERIFY_WRITE, buf, nr)) { |
| 594 | printk(KERN_WARNING "%s(%d) n_hdlc_tty_read() can't verify user " |
| 595 | "buffer\n", __FILE__, __LINE__); |
| 596 | return -EFAULT; |
| 597 | } |
| 598 | |
Paul Fulghum | 1035b63 | 2011-01-18 14:03:25 -0800 | [diff] [blame] | 599 | add_wait_queue(&tty->read_wait, &wait); |
Alan Cox | 04f378b | 2008-04-30 00:53:29 -0700 | [diff] [blame] | 600 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 601 | for (;;) { |
Peter Hurley | 1a48632 | 2015-04-13 13:24:34 -0400 | [diff] [blame] | 602 | if (test_bit(TTY_OTHER_DONE, &tty->flags)) { |
Paul Fulghum | 1035b63 | 2011-01-18 14:03:25 -0800 | [diff] [blame] | 603 | ret = -EIO; |
| 604 | break; |
Alan Cox | 04f378b | 2008-04-30 00:53:29 -0700 | [diff] [blame] | 605 | } |
Paul Fulghum | 1035b63 | 2011-01-18 14:03:25 -0800 | [diff] [blame] | 606 | if (tty_hung_up_p(file)) |
| 607 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 608 | |
Paul Fulghum | 1035b63 | 2011-01-18 14:03:25 -0800 | [diff] [blame] | 609 | set_current_state(TASK_INTERRUPTIBLE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 610 | |
| 611 | rbuf = n_hdlc_buf_get(&n_hdlc->rx_buf_list); |
Paul Fulghum | 1035b63 | 2011-01-18 14:03:25 -0800 | [diff] [blame] | 612 | if (rbuf) { |
| 613 | if (rbuf->count > nr) { |
| 614 | /* too large for caller's buffer */ |
| 615 | ret = -EOVERFLOW; |
| 616 | } else { |
| 617 | if (copy_to_user(buf, rbuf->buf, rbuf->count)) |
| 618 | ret = -EFAULT; |
| 619 | else |
| 620 | ret = rbuf->count; |
| 621 | } |
| 622 | |
| 623 | if (n_hdlc->rx_free_buf_list.count > |
| 624 | DEFAULT_RX_BUF_COUNT) |
| 625 | kfree(rbuf); |
| 626 | else |
| 627 | n_hdlc_buf_put(&n_hdlc->rx_free_buf_list, rbuf); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 628 | break; |
Paul Fulghum | 1035b63 | 2011-01-18 14:03:25 -0800 | [diff] [blame] | 629 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 630 | |
| 631 | /* no data */ |
Alan Cox | 04f378b | 2008-04-30 00:53:29 -0700 | [diff] [blame] | 632 | if (file->f_flags & O_NONBLOCK) { |
Paul Fulghum | 1035b63 | 2011-01-18 14:03:25 -0800 | [diff] [blame] | 633 | ret = -EAGAIN; |
| 634 | break; |
Alan Cox | 04f378b | 2008-04-30 00:53:29 -0700 | [diff] [blame] | 635 | } |
Paul Fulghum | 1035b63 | 2011-01-18 14:03:25 -0800 | [diff] [blame] | 636 | |
| 637 | schedule(); |
| 638 | |
Alan Cox | 04f378b | 2008-04-30 00:53:29 -0700 | [diff] [blame] | 639 | if (signal_pending(current)) { |
Paul Fulghum | 1035b63 | 2011-01-18 14:03:25 -0800 | [diff] [blame] | 640 | ret = -EINTR; |
| 641 | break; |
Alan Cox | 04f378b | 2008-04-30 00:53:29 -0700 | [diff] [blame] | 642 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 643 | } |
Paul Fulghum | 1035b63 | 2011-01-18 14:03:25 -0800 | [diff] [blame] | 644 | |
| 645 | remove_wait_queue(&tty->read_wait, &wait); |
| 646 | __set_current_state(TASK_RUNNING); |
| 647 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 648 | return ret; |
| 649 | |
| 650 | } /* end of n_hdlc_tty_read() */ |
| 651 | |
| 652 | /** |
| 653 | * n_hdlc_tty_write - write a single frame of data to device |
| 654 | * @tty - pointer to associated tty device instance data |
| 655 | * @file - pointer to file object data |
| 656 | * @data - pointer to transmit data (one frame) |
| 657 | * @count - size of transmit frame in bytes |
| 658 | * |
| 659 | * Returns the number of bytes written (or error code). |
| 660 | */ |
| 661 | static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file, |
| 662 | const unsigned char *data, size_t count) |
| 663 | { |
| 664 | struct n_hdlc *n_hdlc = tty2n_hdlc (tty); |
| 665 | int error = 0; |
| 666 | DECLARE_WAITQUEUE(wait, current); |
| 667 | struct n_hdlc_buf *tbuf; |
| 668 | |
| 669 | if (debuglevel >= DEBUG_LEVEL_INFO) |
| 670 | printk("%s(%d)n_hdlc_tty_write() called count=%Zd\n", |
| 671 | __FILE__,__LINE__,count); |
| 672 | |
| 673 | /* Verify pointers */ |
| 674 | if (!n_hdlc) |
| 675 | return -EIO; |
| 676 | |
| 677 | if (n_hdlc->magic != HDLC_MAGIC) |
| 678 | return -EIO; |
| 679 | |
| 680 | /* verify frame size */ |
| 681 | if (count > maxframe ) { |
| 682 | if (debuglevel & DEBUG_LEVEL_INFO) |
| 683 | printk (KERN_WARNING |
| 684 | "n_hdlc_tty_write: truncating user packet " |
| 685 | "from %lu to %d\n", (unsigned long) count, |
| 686 | maxframe ); |
| 687 | count = maxframe; |
| 688 | } |
| 689 | |
| 690 | add_wait_queue(&tty->write_wait, &wait); |
Paul Fulghum | 1035b63 | 2011-01-18 14:03:25 -0800 | [diff] [blame] | 691 | |
| 692 | for (;;) { |
| 693 | set_current_state(TASK_INTERRUPTIBLE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 694 | |
Paul Fulghum | 1035b63 | 2011-01-18 14:03:25 -0800 | [diff] [blame] | 695 | tbuf = n_hdlc_buf_get(&n_hdlc->tx_free_buf_list); |
| 696 | if (tbuf) |
| 697 | break; |
| 698 | |
Paul Fulghum | c72f527 | 2008-07-22 11:21:19 +0100 | [diff] [blame] | 699 | if (file->f_flags & O_NONBLOCK) { |
| 700 | error = -EAGAIN; |
| 701 | break; |
| 702 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 703 | schedule(); |
| 704 | |
| 705 | n_hdlc = tty2n_hdlc (tty); |
| 706 | if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC || |
| 707 | tty != n_hdlc->tty) { |
| 708 | printk("n_hdlc_tty_write: %p invalid after wait!\n", n_hdlc); |
| 709 | error = -EIO; |
| 710 | break; |
| 711 | } |
| 712 | |
| 713 | if (signal_pending(current)) { |
| 714 | error = -EINTR; |
| 715 | break; |
| 716 | } |
| 717 | } |
| 718 | |
Paul Fulghum | 1035b63 | 2011-01-18 14:03:25 -0800 | [diff] [blame] | 719 | __set_current_state(TASK_RUNNING); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 720 | remove_wait_queue(&tty->write_wait, &wait); |
| 721 | |
| 722 | if (!error) { |
| 723 | /* Retrieve the user's buffer */ |
| 724 | memcpy(tbuf->buf, data, count); |
| 725 | |
| 726 | /* Send the data */ |
| 727 | tbuf->count = error = count; |
| 728 | n_hdlc_buf_put(&n_hdlc->tx_buf_list,tbuf); |
| 729 | n_hdlc_send_frames(n_hdlc,tty); |
| 730 | } |
Paul Fulghum | 1035b63 | 2011-01-18 14:03:25 -0800 | [diff] [blame] | 731 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 732 | return error; |
| 733 | |
| 734 | } /* end of n_hdlc_tty_write() */ |
| 735 | |
| 736 | /** |
| 737 | * n_hdlc_tty_ioctl - process IOCTL system call for the tty device. |
| 738 | * @tty - pointer to tty instance data |
| 739 | * @file - pointer to open file object for device |
| 740 | * @cmd - IOCTL command code |
| 741 | * @arg - argument for IOCTL call (cmd dependent) |
| 742 | * |
| 743 | * Returns command dependent result. |
| 744 | */ |
| 745 | static int n_hdlc_tty_ioctl(struct tty_struct *tty, struct file *file, |
| 746 | unsigned int cmd, unsigned long arg) |
| 747 | { |
| 748 | struct n_hdlc *n_hdlc = tty2n_hdlc (tty); |
| 749 | int error = 0; |
| 750 | int count; |
| 751 | unsigned long flags; |
| 752 | |
| 753 | if (debuglevel >= DEBUG_LEVEL_INFO) |
| 754 | printk("%s(%d)n_hdlc_tty_ioctl() called %d\n", |
| 755 | __FILE__,__LINE__,cmd); |
| 756 | |
| 757 | /* Verify the status of the device */ |
| 758 | if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC) |
| 759 | return -EBADF; |
| 760 | |
| 761 | switch (cmd) { |
| 762 | case FIONREAD: |
| 763 | /* report count of read data available */ |
| 764 | /* in next available frame (if any) */ |
| 765 | spin_lock_irqsave(&n_hdlc->rx_buf_list.spinlock,flags); |
| 766 | if (n_hdlc->rx_buf_list.head) |
| 767 | count = n_hdlc->rx_buf_list.head->count; |
| 768 | else |
| 769 | count = 0; |
| 770 | spin_unlock_irqrestore(&n_hdlc->rx_buf_list.spinlock,flags); |
| 771 | error = put_user(count, (int __user *)arg); |
| 772 | break; |
| 773 | |
| 774 | case TIOCOUTQ: |
| 775 | /* get the pending tx byte count in the driver */ |
Alan Cox | f34d7a5 | 2008-04-30 00:54:13 -0700 | [diff] [blame] | 776 | count = tty_chars_in_buffer(tty); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 777 | /* add size of next output frame in queue */ |
| 778 | spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock,flags); |
| 779 | if (n_hdlc->tx_buf_list.head) |
| 780 | count += n_hdlc->tx_buf_list.head->count; |
| 781 | spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock,flags); |
| 782 | error = put_user(count, (int __user *)arg); |
| 783 | break; |
| 784 | |
Paul Fulghum | be10eb7 | 2009-06-22 18:42:56 +0100 | [diff] [blame] | 785 | case TCFLSH: |
| 786 | switch (arg) { |
| 787 | case TCIOFLUSH: |
| 788 | case TCOFLUSH: |
| 789 | flush_tx_queue(tty); |
| 790 | } |
| 791 | /* fall through to default */ |
| 792 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 793 | default: |
Alan Cox | 47afa7a | 2008-10-13 10:44:17 +0100 | [diff] [blame] | 794 | error = n_tty_ioctl_helper(tty, file, cmd, arg); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 795 | break; |
| 796 | } |
| 797 | return error; |
| 798 | |
| 799 | } /* end of n_hdlc_tty_ioctl() */ |
| 800 | |
| 801 | /** |
| 802 | * n_hdlc_tty_poll - TTY callback for poll system call |
| 803 | * @tty - pointer to tty instance data |
| 804 | * @filp - pointer to open file object for device |
| 805 | * @poll_table - wait queue for operations |
| 806 | * |
| 807 | * Determine which operations (read/write) will not block and return info |
| 808 | * to caller. |
| 809 | * Returns a bit mask containing info on which ops will not block. |
| 810 | */ |
| 811 | static unsigned int n_hdlc_tty_poll(struct tty_struct *tty, struct file *filp, |
| 812 | poll_table *wait) |
| 813 | { |
| 814 | struct n_hdlc *n_hdlc = tty2n_hdlc (tty); |
| 815 | unsigned int mask = 0; |
| 816 | |
| 817 | if (debuglevel >= DEBUG_LEVEL_INFO) |
| 818 | printk("%s(%d)n_hdlc_tty_poll() called\n",__FILE__,__LINE__); |
| 819 | |
| 820 | if (n_hdlc && n_hdlc->magic == HDLC_MAGIC && tty == n_hdlc->tty) { |
| 821 | /* queue current process into any wait queue that */ |
| 822 | /* may awaken in the future (read and write) */ |
| 823 | |
| 824 | poll_wait(filp, &tty->read_wait, wait); |
| 825 | poll_wait(filp, &tty->write_wait, wait); |
| 826 | |
| 827 | /* set bits for operations that won't block */ |
Alan Cox | 9c1729d | 2007-07-15 23:39:43 -0700 | [diff] [blame] | 828 | if (n_hdlc->rx_buf_list.head) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 829 | mask |= POLLIN | POLLRDNORM; /* readable */ |
Peter Hurley | 1a48632 | 2015-04-13 13:24:34 -0400 | [diff] [blame] | 830 | if (test_bit(TTY_OTHER_DONE, &tty->flags)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 831 | mask |= POLLHUP; |
Alan Cox | 9c1729d | 2007-07-15 23:39:43 -0700 | [diff] [blame] | 832 | if (tty_hung_up_p(filp)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 833 | mask |= POLLHUP; |
Alan Cox | 9c1729d | 2007-07-15 23:39:43 -0700 | [diff] [blame] | 834 | if (!tty_is_writelocked(tty) && |
| 835 | n_hdlc->tx_free_buf_list.head) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 836 | mask |= POLLOUT | POLLWRNORM; /* writable */ |
| 837 | } |
| 838 | return mask; |
| 839 | } /* end of n_hdlc_tty_poll() */ |
| 840 | |
| 841 | /** |
| 842 | * n_hdlc_alloc - allocate an n_hdlc instance data structure |
| 843 | * |
| 844 | * Returns a pointer to newly created structure if success, otherwise %NULL |
| 845 | */ |
| 846 | static struct n_hdlc *n_hdlc_alloc(void) |
| 847 | { |
| 848 | struct n_hdlc_buf *buf; |
| 849 | int i; |
Fabian Frederick | 8e25f8c | 2014-05-26 21:32:42 +0200 | [diff] [blame] | 850 | struct n_hdlc *n_hdlc = kzalloc(sizeof(*n_hdlc), GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 851 | |
| 852 | if (!n_hdlc) |
| 853 | return NULL; |
| 854 | |
Jiri Slaby | e9b736d | 2015-11-26 19:28:26 +0100 | [diff] [blame] | 855 | spin_lock_init(&n_hdlc->rx_free_buf_list.spinlock); |
| 856 | spin_lock_init(&n_hdlc->tx_free_buf_list.spinlock); |
| 857 | spin_lock_init(&n_hdlc->rx_buf_list.spinlock); |
| 858 | spin_lock_init(&n_hdlc->tx_buf_list.spinlock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 859 | |
| 860 | /* allocate free rx buffer list */ |
| 861 | for(i=0;i<DEFAULT_RX_BUF_COUNT;i++) { |
| 862 | buf = kmalloc(N_HDLC_BUF_SIZE, GFP_KERNEL); |
| 863 | if (buf) |
| 864 | n_hdlc_buf_put(&n_hdlc->rx_free_buf_list,buf); |
| 865 | else if (debuglevel >= DEBUG_LEVEL_INFO) |
| 866 | printk("%s(%d)n_hdlc_alloc(), kalloc() failed for rx buffer %d\n",__FILE__,__LINE__, i); |
| 867 | } |
| 868 | |
| 869 | /* allocate free tx buffer list */ |
| 870 | for(i=0;i<DEFAULT_TX_BUF_COUNT;i++) { |
| 871 | buf = kmalloc(N_HDLC_BUF_SIZE, GFP_KERNEL); |
| 872 | if (buf) |
| 873 | n_hdlc_buf_put(&n_hdlc->tx_free_buf_list,buf); |
| 874 | else if (debuglevel >= DEBUG_LEVEL_INFO) |
| 875 | printk("%s(%d)n_hdlc_alloc(), kalloc() failed for tx buffer %d\n",__FILE__,__LINE__, i); |
| 876 | } |
| 877 | |
| 878 | /* Initialize the control block */ |
| 879 | n_hdlc->magic = HDLC_MAGIC; |
| 880 | n_hdlc->flags = 0; |
| 881 | |
| 882 | return n_hdlc; |
| 883 | |
| 884 | } /* end of n_hdlc_alloc() */ |
| 885 | |
| 886 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 887 | * n_hdlc_buf_put - add specified HDLC buffer to tail of specified list |
| 888 | * @list - pointer to buffer list |
| 889 | * @buf - pointer to buffer |
| 890 | */ |
| 891 | static void n_hdlc_buf_put(struct n_hdlc_buf_list *list, |
| 892 | struct n_hdlc_buf *buf) |
| 893 | { |
| 894 | unsigned long flags; |
| 895 | spin_lock_irqsave(&list->spinlock,flags); |
| 896 | |
| 897 | buf->link=NULL; |
Alan Cox | 9c1729d | 2007-07-15 23:39:43 -0700 | [diff] [blame] | 898 | if (list->tail) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 899 | list->tail->link = buf; |
| 900 | else |
| 901 | list->head = buf; |
| 902 | list->tail = buf; |
| 903 | (list->count)++; |
| 904 | |
| 905 | spin_unlock_irqrestore(&list->spinlock,flags); |
| 906 | |
| 907 | } /* end of n_hdlc_buf_put() */ |
| 908 | |
| 909 | /** |
| 910 | * n_hdlc_buf_get - remove and return an HDLC buffer from list |
| 911 | * @list - pointer to HDLC buffer list |
| 912 | * |
| 913 | * Remove and return an HDLC buffer from the head of the specified HDLC buffer |
| 914 | * list. |
| 915 | * Returns a pointer to HDLC buffer if available, otherwise %NULL. |
| 916 | */ |
| 917 | static struct n_hdlc_buf* n_hdlc_buf_get(struct n_hdlc_buf_list *list) |
| 918 | { |
| 919 | unsigned long flags; |
| 920 | struct n_hdlc_buf *buf; |
| 921 | spin_lock_irqsave(&list->spinlock,flags); |
| 922 | |
| 923 | buf = list->head; |
| 924 | if (buf) { |
| 925 | list->head = buf->link; |
| 926 | (list->count)--; |
| 927 | } |
| 928 | if (!list->head) |
| 929 | list->tail = NULL; |
| 930 | |
| 931 | spin_unlock_irqrestore(&list->spinlock,flags); |
| 932 | return buf; |
| 933 | |
| 934 | } /* end of n_hdlc_buf_get() */ |
| 935 | |
| 936 | static char hdlc_banner[] __initdata = |
Paul Fulghum | be10eb7 | 2009-06-22 18:42:56 +0100 | [diff] [blame] | 937 | KERN_INFO "HDLC line discipline maxframe=%u\n"; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 938 | static char hdlc_register_ok[] __initdata = |
| 939 | KERN_INFO "N_HDLC line discipline registered.\n"; |
| 940 | static char hdlc_register_fail[] __initdata = |
| 941 | KERN_ERR "error registering line discipline: %d\n"; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 942 | |
| 943 | static int __init n_hdlc_init(void) |
| 944 | { |
| 945 | int status; |
| 946 | |
| 947 | /* range check maxframe arg */ |
| 948 | if (maxframe < 4096) |
| 949 | maxframe = 4096; |
| 950 | else if (maxframe > 65535) |
| 951 | maxframe = 65535; |
| 952 | |
| 953 | printk(hdlc_banner, maxframe); |
| 954 | |
| 955 | status = tty_register_ldisc(N_HDLC, &n_hdlc_ldisc); |
| 956 | if (!status) |
| 957 | printk(hdlc_register_ok); |
| 958 | else |
| 959 | printk(hdlc_register_fail, status); |
| 960 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 961 | return status; |
| 962 | |
| 963 | } /* end of init_module() */ |
| 964 | |
| 965 | static char hdlc_unregister_ok[] __exitdata = |
| 966 | KERN_INFO "N_HDLC: line discipline unregistered\n"; |
| 967 | static char hdlc_unregister_fail[] __exitdata = |
| 968 | KERN_ERR "N_HDLC: can't unregister line discipline (err = %d)\n"; |
| 969 | |
| 970 | static void __exit n_hdlc_exit(void) |
| 971 | { |
| 972 | /* Release tty registration of line discipline */ |
Alexey Dobriyan | 64ccd71 | 2005-06-23 00:10:33 -0700 | [diff] [blame] | 973 | int status = tty_unregister_ldisc(N_HDLC); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 974 | |
| 975 | if (status) |
| 976 | printk(hdlc_unregister_fail, status); |
| 977 | else |
| 978 | printk(hdlc_unregister_ok); |
| 979 | } |
| 980 | |
| 981 | module_init(n_hdlc_init); |
| 982 | module_exit(n_hdlc_exit); |
| 983 | |
| 984 | MODULE_LICENSE("GPL"); |
| 985 | MODULE_AUTHOR("Paul Fulghum paulkf@microgate.com"); |
| 986 | module_param(debuglevel, int, 0); |
| 987 | module_param(maxframe, int, 0); |
| 988 | MODULE_ALIAS_LDISC(N_HDLC); |