1 /* 2 * IBM eServer Hypervisor Virtual Console Server Device Driver 3 * Copyright (C) 2003, 2004 IBM Corp. 4 * Ryan S. Arnold (rsa@us.ibm.com) 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License, or 9 * (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, write to the Free Software 18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 19 * 20 * Author(s) : Ryan S. Arnold <rsa@us.ibm.com> 21 * 22 * This is the device driver for the IBM Hypervisor Virtual Console Server, 23 * "hvcs". The IBM hvcs provides a tty driver interface to allow Linux 24 * user space applications access to the system consoles of logically 25 * partitioned operating systems, e.g. Linux, running on the same partitioned 26 * Power5 ppc64 system. Physical hardware consoles per partition are not 27 * practical on this hardware so system consoles are accessed by this driver 28 * using inter-partition firmware interfaces to virtual terminal devices. 29 * 30 * A vty is known to the HMC as a "virtual serial server adapter". It is a 31 * virtual terminal device that is created by firmware upon partition creation 32 * to act as a partitioned OS's console device. 33 * 34 * Firmware dynamically (via hotplug) exposes vty-servers to a running ppc64 35 * Linux system upon their creation by the HMC or their exposure during boot. 36 * The non-user interactive backend of this driver is implemented as a vio 37 * device driver so that it can receive notification of vty-server lifetimes 38 * after it registers with the vio bus to handle vty-server probe and remove 39 * callbacks. 40 * 41 * Many vty-servers can be configured to connect to one vty, but a vty can 42 * only be actively connected to by a single vty-server, in any manner, at one 43 * time. If the HMC is currently hosting the console for a target Linux 44 * partition; attempts to open the tty device to the partition's console using 45 * the hvcs on any partition will return -EBUSY with every open attempt until 46 * the HMC frees the connection between its vty-server and the desired 47 * partition's vty device. Conversely, a vty-server may only be connected to 48 * a single vty at one time even though it may have several configured vty 49 * partner possibilities. 50 * 51 * Firmware does not provide notification of vty partner changes to this 52 * driver. This means that an HMC Super Admin may add or remove partner vtys 53 * from a vty-server's partner list but the changes will not be signaled to 54 * the vty-server. Firmware only notifies the driver when a vty-server is 55 * added or removed from the system. To compensate for this deficiency, this 56 * driver implements a sysfs update attribute which provides a method for 57 * rescanning partner information upon a user's request. 58 * 59 * Each vty-server, prior to being exposed to this driver is reference counted 60 * using the 2.6 Linux kernel kref construct. 61 * 62 * For direction on installation and usage of this driver please reference 63 * Documentation/powerpc/hvcs.txt. 64 */ 65 66 #include <linux/device.h> 67 #include <linux/init.h> 68 #include <linux/interrupt.h> 69 #include <linux/kernel.h> 70 #include <linux/kref.h> 71 #include <linux/kthread.h> 72 #include <linux/list.h> 73 #include <linux/major.h> 74 #include <linux/module.h> 75 #include <linux/moduleparam.h> 76 #include <linux/sched.h> 77 #include <linux/slab.h> 78 #include <linux/spinlock.h> 79 #include <linux/stat.h> 80 #include <linux/tty.h> 81 #include <linux/tty_flip.h> 82 #include <asm/hvconsole.h> 83 #include <asm/hvcserver.h> 84 #include <linux/uaccess.h> 85 #include <asm/vio.h> 86 87 /* 88 * 1.3.0 -> 1.3.1 In hvcs_open memset(..,0x00,..) instead of memset(..,0x3F,00). 89 * Removed braces around single statements following conditionals. Removed '= 90 * 0' after static int declarations since these default to zero. Removed 91 * list_for_each_safe() and replaced with list_for_each_entry() in 92 * hvcs_get_by_index(). The 'safe' version is un-needed now that the driver is 93 * using spinlocks. Changed spin_lock_irqsave() to spin_lock() when locking 94 * hvcs_structs_lock and hvcs_pi_lock since these are not touched in an int 95 * handler. Initialized hvcs_structs_lock and hvcs_pi_lock to 96 * SPIN_LOCK_UNLOCKED at declaration time rather than in hvcs_module_init(). 97 * Added spin_lock around list_del() in destroy_hvcs_struct() to protect the 98 * list traversals from a deletion. Removed '= NULL' from pointer declaration 99 * statements since they are initialized NULL by default. Removed wmb() 100 * instances from hvcs_try_write(). They probably aren't needed with locking in 101 * place. Added check and cleanup for hvcs_pi_buff = kmalloc() in 102 * hvcs_module_init(). Exposed hvcs_struct.index via a sysfs attribute so that 103 * the coupling between /dev/hvcs* and a vty-server can be automatically 104 * determined. Moved kobject_put() in hvcs_open outside of the 105 * spin_unlock_irqrestore(). 106 * 107 * 1.3.1 -> 1.3.2 Changed method for determining hvcs_struct->index and had it 108 * align with how the tty layer always assigns the lowest index available. This 109 * change resulted in a list of ints that denotes which indexes are available. 110 * Device additions and removals use the new hvcs_get_index() and 111 * hvcs_return_index() helper functions. The list is created with 112 * hvsc_alloc_index_list() and it is destroyed with hvcs_free_index_list(). 113 * Without these fixes hotplug vty-server adapter support goes crazy with this 114 * driver if the user removes a vty-server adapter. Moved free_irq() outside of 115 * the hvcs_final_close() function in order to get it out of the spinlock. 116 * Rearranged hvcs_close(). Cleaned up some printks and did some housekeeping 117 * on the changelog. Removed local CLC_LENGTH and used HVCS_CLC_LENGTH from 118 * arch/powerepc/include/asm/hvcserver.h 119 * 120 * 1.3.2 -> 1.3.3 Replaced yield() in hvcs_close() with tty_wait_until_sent() to 121 * prevent possible lockup with realtime scheduling as similarly pointed out by 122 * akpm in hvc_console. Changed resulted in the removal of hvcs_final_close() 123 * to reorder cleanup operations and prevent discarding of pending data during 124 * an hvcs_close(). Removed spinlock protection of hvcs_struct data members in 125 * hvcs_write_room() and hvcs_chars_in_buffer() because they aren't needed. 126 */ 127 128 #define HVCS_DRIVER_VERSION "1.3.3" 129 130 MODULE_AUTHOR("Ryan S. Arnold <rsa@us.ibm.com>"); 131 MODULE_DESCRIPTION("IBM hvcs (Hypervisor Virtual Console Server) Driver"); 132 MODULE_LICENSE("GPL"); 133 MODULE_VERSION(HVCS_DRIVER_VERSION); 134 135 /* 136 * Wait this long per iteration while trying to push buffered data to the 137 * hypervisor before allowing the tty to complete a close operation. 138 */ 139 #define HVCS_CLOSE_WAIT (HZ/100) /* 1/10 of a second */ 140 141 /* 142 * Since the Linux TTY code does not currently (2-04-2004) support dynamic 143 * addition of tty derived devices and we shouldn't allocate thousands of 144 * tty_device pointers when the number of vty-server & vty partner connections 145 * will most often be much lower than this, we'll arbitrarily allocate 146 * HVCS_DEFAULT_SERVER_ADAPTERS tty_structs and cdev's by default when we 147 * register the tty_driver. This can be overridden using an insmod parameter. 148 */ 149 #define HVCS_DEFAULT_SERVER_ADAPTERS 64 150 151 /* 152 * The user can't insmod with more than HVCS_MAX_SERVER_ADAPTERS hvcs device 153 * nodes as a sanity check. Theoretically there can be over 1 Billion 154 * vty-server & vty partner connections. 155 */ 156 #define HVCS_MAX_SERVER_ADAPTERS 1024 157 158 /* 159 * We let Linux assign us a major number and we start the minors at zero. There 160 * is no intuitive mapping between minor number and the target vty-server 161 * adapter except that each new vty-server adapter is always assigned to the 162 * smallest minor number available. 163 */ 164 #define HVCS_MINOR_START 0 165 166 /* 167 * The hcall interface involves putting 8 chars into each of two registers. 168 * We load up those 2 registers (in arch/powerpc/platforms/pseries/hvconsole.c) 169 * by casting char[16] to long[2]. It would work without __ALIGNED__, but a 170 * little (tiny) bit slower because an unaligned load is slower than aligned 171 * load. 172 */ 173 #define __ALIGNED__ __attribute__((__aligned__(8))) 174 175 /* 176 * How much data can firmware send with each hvc_put_chars()? Maybe this 177 * should be moved into an architecture specific area. 178 */ 179 #define HVCS_BUFF_LEN 16 180 181 /* 182 * This is the maximum amount of data we'll let the user send us (hvcs_write) at 183 * once in a chunk as a sanity check. 184 */ 185 #define HVCS_MAX_FROM_USER 4096 186 187 /* 188 * Be careful when adding flags to this line discipline. Don't add anything 189 * that will cause echoing or we'll go into recursive loop echoing chars back 190 * and forth with the console drivers. 191 */ 192 static const struct ktermios hvcs_tty_termios = { 193 .c_iflag = IGNBRK | IGNPAR, 194 .c_oflag = OPOST, 195 .c_cflag = B38400 | CS8 | CREAD | HUPCL, 196 .c_cc = INIT_C_CC, 197 .c_ispeed = 38400, 198 .c_ospeed = 38400 199 }; 200 201 /* 202 * This value is used to take the place of a command line parameter when the 203 * module is inserted. It starts as -1 and stays as such if the user doesn't 204 * specify a module insmod parameter. If they DO specify one then it is set to 205 * the value of the integer passed in. 206 */ 207 static int hvcs_parm_num_devs = -1; 208 module_param(hvcs_parm_num_devs, int, 0); 209 210 static const char hvcs_driver_name[] = "hvcs"; 211 static const char hvcs_device_node[] = "hvcs"; 212 static const char hvcs_driver_string[] 213 = "IBM hvcs (Hypervisor Virtual Console Server) Driver"; 214 215 /* Status of partner info rescan triggered via sysfs. */ 216 static int hvcs_rescan_status; 217 218 static struct tty_driver *hvcs_tty_driver; 219 220 /* 221 * In order to be somewhat sane this driver always associates the hvcs_struct 222 * index element with the numerically equal tty->index. This means that a 223 * hotplugged vty-server adapter will always map to the lowest index valued 224 * device node. If vty-servers were hotplug removed from the system and then 225 * new ones added the new vty-server may have the largest slot number of all 226 * the vty-server adapters in the partition but it may have the lowest dev node 227 * index of all the adapters due to the hole left by the hotplug removed 228 * adapter. There are a set of functions provided to get the lowest index for 229 * a new device as well as return the index to the list. This list is allocated 230 * with a number of elements equal to the number of device nodes requested when 231 * the module was inserted. 232 */ 233 static int *hvcs_index_list; 234 235 /* 236 * How large is the list? This is kept for traversal since the list is 237 * dynamically created. 238 */ 239 static int hvcs_index_count; 240 241 /* 242 * Used by the khvcsd to pick up I/O operations when the kernel_thread is 243 * already awake but potentially shifted to TASK_INTERRUPTIBLE state. 244 */ 245 static int hvcs_kicked; 246 247 /* 248 * Use by the kthread construct for task operations like waking the sleeping 249 * thread and stopping the kthread. 250 */ 251 static struct task_struct *hvcs_task; 252 253 /* 254 * We allocate this for the use of all of the hvcs_structs when they fetch 255 * partner info. 256 */ 257 static unsigned long *hvcs_pi_buff; 258 259 /* Only allow one hvcs_struct to use the hvcs_pi_buff at a time. */ 260 static DEFINE_SPINLOCK(hvcs_pi_lock); 261 262 /* One vty-server per hvcs_struct */ 263 struct hvcs_struct { 264 struct tty_port port; 265 spinlock_t lock; 266 267 /* 268 * This index identifies this hvcs device as the complement to a 269 * specific tty index. 270 */ 271 unsigned int index; 272 273 /* 274 * Used to tell the driver kernel_thread what operations need to take 275 * place upon this hvcs_struct instance. 276 */ 277 int todo_mask; 278 279 /* 280 * This buffer is required so that when hvcs_write_room() reports that 281 * it can send HVCS_BUFF_LEN characters that it will buffer the full 282 * HVCS_BUFF_LEN characters if need be. This is essential for opost 283 * writes since they do not do high level buffering and expect to be 284 * able to send what the driver commits to sending buffering 285 * [e.g. tab to space conversions in n_tty.c opost()]. 286 */ 287 char buffer[HVCS_BUFF_LEN]; 288 int chars_in_buffer; 289 290 /* 291 * Any variable below is valid before a tty is connected and 292 * stays valid after the tty is disconnected. These shouldn't be 293 * whacked until the kobject refcount reaches zero though some entries 294 * may be changed via sysfs initiatives. 295 */ 296 int connected; /* is the vty-server currently connected to a vty? */ 297 uint32_t p_unit_address; /* partner unit address */ 298 uint32_t p_partition_ID; /* partner partition ID */ 299 char p_location_code[HVCS_CLC_LENGTH + 1]; /* CLC + Null Term */ 300 struct list_head next; /* list management */ 301 struct vio_dev *vdev; 302 }; 303 304 static LIST_HEAD(hvcs_structs); 305 static DEFINE_SPINLOCK(hvcs_structs_lock); 306 static DEFINE_MUTEX(hvcs_init_mutex); 307 308 static void hvcs_unthrottle(struct tty_struct *tty); 309 static void hvcs_throttle(struct tty_struct *tty); 310 static irqreturn_t hvcs_handle_interrupt(int irq, void *dev_instance); 311 312 static int hvcs_write(struct tty_struct *tty, 313 const unsigned char *buf, int count); 314 static int hvcs_write_room(struct tty_struct *tty); 315 static int hvcs_chars_in_buffer(struct tty_struct *tty); 316 317 static int hvcs_has_pi(struct hvcs_struct *hvcsd); 318 static void hvcs_set_pi(struct hvcs_partner_info *pi, 319 struct hvcs_struct *hvcsd); 320 static int hvcs_get_pi(struct hvcs_struct *hvcsd); 321 static int hvcs_rescan_devices_list(void); 322 323 static int hvcs_partner_connect(struct hvcs_struct *hvcsd); 324 static void hvcs_partner_free(struct hvcs_struct *hvcsd); 325 326 static int hvcs_enable_device(struct hvcs_struct *hvcsd, 327 uint32_t unit_address, unsigned int irq, struct vio_dev *dev); 328 329 static int hvcs_open(struct tty_struct *tty, struct file *filp); 330 static void hvcs_close(struct tty_struct *tty, struct file *filp); 331 static void hvcs_hangup(struct tty_struct * tty); 332 333 static int hvcs_probe(struct vio_dev *dev, 334 const struct vio_device_id *id); 335 static int hvcs_remove(struct vio_dev *dev); 336 static int __init hvcs_module_init(void); 337 static void __exit hvcs_module_exit(void); 338 static int hvcs_initialize(void); 339 340 #define HVCS_SCHED_READ 0x00000001 341 #define HVCS_QUICK_READ 0x00000002 342 #define HVCS_TRY_WRITE 0x00000004 343 #define HVCS_READ_MASK (HVCS_SCHED_READ | HVCS_QUICK_READ) 344 345 static inline struct hvcs_struct *from_vio_dev(struct vio_dev *viod) 346 { 347 return dev_get_drvdata(&viod->dev); 348 } 349 /* The sysfs interface for the driver and devices */ 350 351 static ssize_t hvcs_partner_vtys_show(struct device *dev, struct device_attribute *attr, char *buf) 352 { 353 struct vio_dev *viod = to_vio_dev(dev); 354 struct hvcs_struct *hvcsd = from_vio_dev(viod); 355 unsigned long flags; 356 int retval; 357 358 spin_lock_irqsave(&hvcsd->lock, flags); 359 retval = sprintf(buf, "%X\n", hvcsd->p_unit_address); 360 spin_unlock_irqrestore(&hvcsd->lock, flags); 361 return retval; 362 } 363 static DEVICE_ATTR(partner_vtys, S_IRUGO, hvcs_partner_vtys_show, NULL); 364 365 static ssize_t hvcs_partner_clcs_show(struct device *dev, struct device_attribute *attr, char *buf) 366 { 367 struct vio_dev *viod = to_vio_dev(dev); 368 struct hvcs_struct *hvcsd = from_vio_dev(viod); 369 unsigned long flags; 370 int retval; 371 372 spin_lock_irqsave(&hvcsd->lock, flags); 373 retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]); 374 spin_unlock_irqrestore(&hvcsd->lock, flags); 375 return retval; 376 } 377 static DEVICE_ATTR(partner_clcs, S_IRUGO, hvcs_partner_clcs_show, NULL); 378 379 static ssize_t hvcs_current_vty_store(struct device *dev, struct device_attribute *attr, const char * buf, 380 size_t count) 381 { 382 /* 383 * Don't need this feature at the present time because firmware doesn't 384 * yet support multiple partners. 385 */ 386 printk(KERN_INFO "HVCS: Denied current_vty change: -EPERM.\n"); 387 return -EPERM; 388 } 389 390 static ssize_t hvcs_current_vty_show(struct device *dev, struct device_attribute *attr, char *buf) 391 { 392 struct vio_dev *viod = to_vio_dev(dev); 393 struct hvcs_struct *hvcsd = from_vio_dev(viod); 394 unsigned long flags; 395 int retval; 396 397 spin_lock_irqsave(&hvcsd->lock, flags); 398 retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]); 399 spin_unlock_irqrestore(&hvcsd->lock, flags); 400 return retval; 401 } 402 403 static DEVICE_ATTR(current_vty, 404 S_IRUGO | S_IWUSR, hvcs_current_vty_show, hvcs_current_vty_store); 405 406 static ssize_t hvcs_vterm_state_store(struct device *dev, struct device_attribute *attr, const char *buf, 407 size_t count) 408 { 409 struct vio_dev *viod = to_vio_dev(dev); 410 struct hvcs_struct *hvcsd = from_vio_dev(viod); 411 unsigned long flags; 412 413 /* writing a '0' to this sysfs entry will result in the disconnect. */ 414 if (simple_strtol(buf, NULL, 0) != 0) 415 return -EINVAL; 416 417 spin_lock_irqsave(&hvcsd->lock, flags); 418 419 if (hvcsd->port.count > 0) { 420 spin_unlock_irqrestore(&hvcsd->lock, flags); 421 printk(KERN_INFO "HVCS: vterm state unchanged. " 422 "The hvcs device node is still in use.\n"); 423 return -EPERM; 424 } 425 426 if (hvcsd->connected == 0) { 427 spin_unlock_irqrestore(&hvcsd->lock, flags); 428 printk(KERN_INFO "HVCS: vterm state unchanged. The" 429 " vty-server is not connected to a vty.\n"); 430 return -EPERM; 431 } 432 433 hvcs_partner_free(hvcsd); 434 printk(KERN_INFO "HVCS: Closed vty-server@%X and" 435 " partner vty@%X:%d connection.\n", 436 hvcsd->vdev->unit_address, 437 hvcsd->p_unit_address, 438 (uint32_t)hvcsd->p_partition_ID); 439 440 spin_unlock_irqrestore(&hvcsd->lock, flags); 441 return count; 442 } 443 444 static ssize_t hvcs_vterm_state_show(struct device *dev, struct device_attribute *attr, char *buf) 445 { 446 struct vio_dev *viod = to_vio_dev(dev); 447 struct hvcs_struct *hvcsd = from_vio_dev(viod); 448 unsigned long flags; 449 int retval; 450 451 spin_lock_irqsave(&hvcsd->lock, flags); 452 retval = sprintf(buf, "%d\n", hvcsd->connected); 453 spin_unlock_irqrestore(&hvcsd->lock, flags); 454 return retval; 455 } 456 static DEVICE_ATTR(vterm_state, S_IRUGO | S_IWUSR, 457 hvcs_vterm_state_show, hvcs_vterm_state_store); 458 459 static ssize_t hvcs_index_show(struct device *dev, struct device_attribute *attr, char *buf) 460 { 461 struct vio_dev *viod = to_vio_dev(dev); 462 struct hvcs_struct *hvcsd = from_vio_dev(viod); 463 unsigned long flags; 464 int retval; 465 466 spin_lock_irqsave(&hvcsd->lock, flags); 467 retval = sprintf(buf, "%d\n", hvcsd->index); 468 spin_unlock_irqrestore(&hvcsd->lock, flags); 469 return retval; 470 } 471 472 static DEVICE_ATTR(index, S_IRUGO, hvcs_index_show, NULL); 473 474 static struct attribute *hvcs_attrs[] = { 475 &dev_attr_partner_vtys.attr, 476 &dev_attr_partner_clcs.attr, 477 &dev_attr_current_vty.attr, 478 &dev_attr_vterm_state.attr, 479 &dev_attr_index.attr, 480 NULL, 481 }; 482 483 static struct attribute_group hvcs_attr_group = { 484 .attrs = hvcs_attrs, 485 }; 486 487 static ssize_t rescan_show(struct device_driver *ddp, char *buf) 488 { 489 /* A 1 means it is updating, a 0 means it is done updating */ 490 return snprintf(buf, PAGE_SIZE, "%d\n", hvcs_rescan_status); 491 } 492 493 static ssize_t rescan_store(struct device_driver *ddp, const char * buf, 494 size_t count) 495 { 496 if ((simple_strtol(buf, NULL, 0) != 1) 497 && (hvcs_rescan_status != 0)) 498 return -EINVAL; 499 500 hvcs_rescan_status = 1; 501 printk(KERN_INFO "HVCS: rescanning partner info for all" 502 " vty-servers.\n"); 503 hvcs_rescan_devices_list(); 504 hvcs_rescan_status = 0; 505 return count; 506 } 507 508 static DRIVER_ATTR_RW(rescan); 509 510 static void hvcs_kick(void) 511 { 512 hvcs_kicked = 1; 513 wmb(); 514 wake_up_process(hvcs_task); 515 } 516 517 static void hvcs_unthrottle(struct tty_struct *tty) 518 { 519 struct hvcs_struct *hvcsd = tty->driver_data; 520 unsigned long flags; 521 522 spin_lock_irqsave(&hvcsd->lock, flags); 523 hvcsd->todo_mask |= HVCS_SCHED_READ; 524 spin_unlock_irqrestore(&hvcsd->lock, flags); 525 hvcs_kick(); 526 } 527 528 static void hvcs_throttle(struct tty_struct *tty) 529 { 530 struct hvcs_struct *hvcsd = tty->driver_data; 531 unsigned long flags; 532 533 spin_lock_irqsave(&hvcsd->lock, flags); 534 vio_disable_interrupts(hvcsd->vdev); 535 spin_unlock_irqrestore(&hvcsd->lock, flags); 536 } 537 538 /* 539 * If the device is being removed we don't have to worry about this interrupt 540 * handler taking any further interrupts because they are disabled which means 541 * the hvcs_struct will always be valid in this handler. 542 */ 543 static irqreturn_t hvcs_handle_interrupt(int irq, void *dev_instance) 544 { 545 struct hvcs_struct *hvcsd = dev_instance; 546 547 spin_lock(&hvcsd->lock); 548 vio_disable_interrupts(hvcsd->vdev); 549 hvcsd->todo_mask |= HVCS_SCHED_READ; 550 spin_unlock(&hvcsd->lock); 551 hvcs_kick(); 552 553 return IRQ_HANDLED; 554 } 555 556 /* This function must be called with the hvcsd->lock held */ 557 static void hvcs_try_write(struct hvcs_struct *hvcsd) 558 { 559 uint32_t unit_address = hvcsd->vdev->unit_address; 560 struct tty_struct *tty = hvcsd->port.tty; 561 int sent; 562 563 if (hvcsd->todo_mask & HVCS_TRY_WRITE) { 564 /* won't send partial writes */ 565 sent = hvc_put_chars(unit_address, 566 &hvcsd->buffer[0], 567 hvcsd->chars_in_buffer ); 568 if (sent > 0) { 569 hvcsd->chars_in_buffer = 0; 570 /* wmb(); */ 571 hvcsd->todo_mask &= ~(HVCS_TRY_WRITE); 572 /* wmb(); */ 573 574 /* 575 * We are still obligated to deliver the data to the 576 * hypervisor even if the tty has been closed because 577 * we committed to delivering it. But don't try to wake 578 * a non-existent tty. 579 */ 580 if (tty) { 581 tty_wakeup(tty); 582 } 583 } 584 } 585 } 586 587 static int hvcs_io(struct hvcs_struct *hvcsd) 588 { 589 uint32_t unit_address; 590 struct tty_struct *tty; 591 char buf[HVCS_BUFF_LEN] __ALIGNED__; 592 unsigned long flags; 593 int got = 0; 594 595 spin_lock_irqsave(&hvcsd->lock, flags); 596 597 unit_address = hvcsd->vdev->unit_address; 598 tty = hvcsd->port.tty; 599 600 hvcs_try_write(hvcsd); 601 602 if (!tty || tty_throttled(tty)) { 603 hvcsd->todo_mask &= ~(HVCS_READ_MASK); 604 goto bail; 605 } else if (!(hvcsd->todo_mask & (HVCS_READ_MASK))) 606 goto bail; 607 608 /* remove the read masks */ 609 hvcsd->todo_mask &= ~(HVCS_READ_MASK); 610 611 if (tty_buffer_request_room(&hvcsd->port, HVCS_BUFF_LEN) >= HVCS_BUFF_LEN) { 612 got = hvc_get_chars(unit_address, 613 &buf[0], 614 HVCS_BUFF_LEN); 615 tty_insert_flip_string(&hvcsd->port, buf, got); 616 } 617 618 /* Give the TTY time to process the data we just sent. */ 619 if (got) 620 hvcsd->todo_mask |= HVCS_QUICK_READ; 621 622 spin_unlock_irqrestore(&hvcsd->lock, flags); 623 /* This is synch because tty->low_latency == 1 */ 624 if(got) 625 tty_flip_buffer_push(&hvcsd->port); 626 627 if (!got) { 628 /* Do this _after_ the flip_buffer_push */ 629 spin_lock_irqsave(&hvcsd->lock, flags); 630 vio_enable_interrupts(hvcsd->vdev); 631 spin_unlock_irqrestore(&hvcsd->lock, flags); 632 } 633 634 return hvcsd->todo_mask; 635 636 bail: 637 spin_unlock_irqrestore(&hvcsd->lock, flags); 638 return hvcsd->todo_mask; 639 } 640 641 static int khvcsd(void *unused) 642 { 643 struct hvcs_struct *hvcsd; 644 int hvcs_todo_mask; 645 646 __set_current_state(TASK_RUNNING); 647 648 do { 649 hvcs_todo_mask = 0; 650 hvcs_kicked = 0; 651 wmb(); 652 653 spin_lock(&hvcs_structs_lock); 654 list_for_each_entry(hvcsd, &hvcs_structs, next) { 655 hvcs_todo_mask |= hvcs_io(hvcsd); 656 } 657 spin_unlock(&hvcs_structs_lock); 658 659 /* 660 * If any of the hvcs adapters want to try a write or quick read 661 * don't schedule(), yield a smidgen then execute the hvcs_io 662 * thread again for those that want the write. 663 */ 664 if (hvcs_todo_mask & (HVCS_TRY_WRITE | HVCS_QUICK_READ)) { 665 yield(); 666 continue; 667 } 668 669 set_current_state(TASK_INTERRUPTIBLE); 670 if (!hvcs_kicked) 671 schedule(); 672 __set_current_state(TASK_RUNNING); 673 } while (!kthread_should_stop()); 674 675 return 0; 676 } 677 678 static const struct vio_device_id hvcs_driver_table[] = { 679 {"serial-server", "hvterm2"}, 680 { "", "" } 681 }; 682 MODULE_DEVICE_TABLE(vio, hvcs_driver_table); 683 684 static void hvcs_return_index(int index) 685 { 686 /* Paranoia check */ 687 if (!hvcs_index_list) 688 return; 689 if (index < 0 || index >= hvcs_index_count) 690 return; 691 if (hvcs_index_list[index] == -1) 692 return; 693 else 694 hvcs_index_list[index] = -1; 695 } 696 697 static void hvcs_destruct_port(struct tty_port *p) 698 { 699 struct hvcs_struct *hvcsd = container_of(p, struct hvcs_struct, port); 700 struct vio_dev *vdev; 701 unsigned long flags; 702 703 spin_lock(&hvcs_structs_lock); 704 spin_lock_irqsave(&hvcsd->lock, flags); 705 706 /* the list_del poisons the pointers */ 707 list_del(&(hvcsd->next)); 708 709 if (hvcsd->connected == 1) { 710 hvcs_partner_free(hvcsd); 711 printk(KERN_INFO "HVCS: Closed vty-server@%X and" 712 " partner vty@%X:%d connection.\n", 713 hvcsd->vdev->unit_address, 714 hvcsd->p_unit_address, 715 (uint32_t)hvcsd->p_partition_ID); 716 } 717 printk(KERN_INFO "HVCS: Destroyed hvcs_struct for vty-server@%X.\n", 718 hvcsd->vdev->unit_address); 719 720 vdev = hvcsd->vdev; 721 hvcsd->vdev = NULL; 722 723 hvcsd->p_unit_address = 0; 724 hvcsd->p_partition_ID = 0; 725 hvcs_return_index(hvcsd->index); 726 memset(&hvcsd->p_location_code[0], 0x00, HVCS_CLC_LENGTH + 1); 727 728 spin_unlock_irqrestore(&hvcsd->lock, flags); 729 spin_unlock(&hvcs_structs_lock); 730 731 sysfs_remove_group(&vdev->dev.kobj, &hvcs_attr_group); 732 733 kfree(hvcsd); 734 } 735 736 static const struct tty_port_operations hvcs_port_ops = { 737 .destruct = hvcs_destruct_port, 738 }; 739 740 static int hvcs_get_index(void) 741 { 742 int i; 743 /* Paranoia check */ 744 if (!hvcs_index_list) { 745 printk(KERN_ERR "HVCS: hvcs_index_list NOT valid!.\n"); 746 return -EFAULT; 747 } 748 /* Find the numerically lowest first free index. */ 749 for(i = 0; i < hvcs_index_count; i++) { 750 if (hvcs_index_list[i] == -1) { 751 hvcs_index_list[i] = 0; 752 return i; 753 } 754 } 755 return -1; 756 } 757 758 static int hvcs_probe( 759 struct vio_dev *dev, 760 const struct vio_device_id *id) 761 { 762 struct hvcs_struct *hvcsd; 763 int index, rc; 764 int retval; 765 766 if (!dev || !id) { 767 printk(KERN_ERR "HVCS: probed with invalid parameter.\n"); 768 return -EPERM; 769 } 770 771 /* Make sure we are properly initialized */ 772 rc = hvcs_initialize(); 773 if (rc) { 774 pr_err("HVCS: Failed to initialize core driver.\n"); 775 return rc; 776 } 777 778 /* early to avoid cleanup on failure */ 779 index = hvcs_get_index(); 780 if (index < 0) { 781 return -EFAULT; 782 } 783 784 hvcsd = kzalloc(sizeof(*hvcsd), GFP_KERNEL); 785 if (!hvcsd) 786 return -ENODEV; 787 788 tty_port_init(&hvcsd->port); 789 hvcsd->port.ops = &hvcs_port_ops; 790 spin_lock_init(&hvcsd->lock); 791 792 hvcsd->vdev = dev; 793 dev_set_drvdata(&dev->dev, hvcsd); 794 795 hvcsd->index = index; 796 797 /* hvcsd->index = ++hvcs_struct_count; */ 798 hvcsd->chars_in_buffer = 0; 799 hvcsd->todo_mask = 0; 800 hvcsd->connected = 0; 801 802 /* 803 * This will populate the hvcs_struct's partner info fields for the 804 * first time. 805 */ 806 if (hvcs_get_pi(hvcsd)) { 807 printk(KERN_ERR "HVCS: Failed to fetch partner" 808 " info for vty-server@%X on device probe.\n", 809 hvcsd->vdev->unit_address); 810 } 811 812 /* 813 * If a user app opens a tty that corresponds to this vty-server before 814 * the hvcs_struct has been added to the devices list then the user app 815 * will get -ENODEV. 816 */ 817 spin_lock(&hvcs_structs_lock); 818 list_add_tail(&(hvcsd->next), &hvcs_structs); 819 spin_unlock(&hvcs_structs_lock); 820 821 retval = sysfs_create_group(&dev->dev.kobj, &hvcs_attr_group); 822 if (retval) { 823 printk(KERN_ERR "HVCS: Can't create sysfs attrs for vty-server@%X\n", 824 hvcsd->vdev->unit_address); 825 return retval; 826 } 827 828 printk(KERN_INFO "HVCS: vty-server@%X added to the vio bus.\n", dev->unit_address); 829 830 /* 831 * DON'T enable interrupts here because there is no user to receive the 832 * data. 833 */ 834 return 0; 835 } 836 837 static int hvcs_remove(struct vio_dev *dev) 838 { 839 struct hvcs_struct *hvcsd = dev_get_drvdata(&dev->dev); 840 unsigned long flags; 841 struct tty_struct *tty; 842 843 if (!hvcsd) 844 return -ENODEV; 845 846 /* By this time the vty-server won't be getting any more interrupts */ 847 848 spin_lock_irqsave(&hvcsd->lock, flags); 849 850 tty = hvcsd->port.tty; 851 852 spin_unlock_irqrestore(&hvcsd->lock, flags); 853 854 /* 855 * Let the last holder of this object cause it to be removed, which 856 * would probably be tty_hangup below. 857 */ 858 tty_port_put(&hvcsd->port); 859 860 /* 861 * The hangup is a scheduled function which will auto chain call 862 * hvcs_hangup. The tty should always be valid at this time unless a 863 * simultaneous tty close already cleaned up the hvcs_struct. 864 */ 865 if (tty) 866 tty_hangup(tty); 867 868 printk(KERN_INFO "HVCS: vty-server@%X removed from the" 869 " vio bus.\n", dev->unit_address); 870 return 0; 871 }; 872 873 static struct vio_driver hvcs_vio_driver = { 874 .id_table = hvcs_driver_table, 875 .probe = hvcs_probe, 876 .remove = hvcs_remove, 877 .name = hvcs_driver_name, 878 }; 879 880 /* Only called from hvcs_get_pi please */ 881 static void hvcs_set_pi(struct hvcs_partner_info *pi, struct hvcs_struct *hvcsd) 882 { 883 hvcsd->p_unit_address = pi->unit_address; 884 hvcsd->p_partition_ID = pi->partition_ID; 885 886 /* copy the null-term char too */ 887 strlcpy(&hvcsd->p_location_code[0], 888 &pi->location_code[0], sizeof(hvcsd->p_location_code)); 889 } 890 891 /* 892 * Traverse the list and add the partner info that is found to the hvcs_struct 893 * struct entry. NOTE: At this time I know that partner info will return a 894 * single entry but in the future there may be multiple partner info entries per 895 * vty-server and you'll want to zero out that list and reset it. If for some 896 * reason you have an old version of this driver but there IS more than one 897 * partner info then hvcsd->p_* will hold the last partner info data from the 898 * firmware query. A good way to update this code would be to replace the three 899 * partner info fields in hvcs_struct with a list of hvcs_partner_info 900 * instances. 901 * 902 * This function must be called with the hvcsd->lock held. 903 */ 904 static int hvcs_get_pi(struct hvcs_struct *hvcsd) 905 { 906 struct hvcs_partner_info *pi; 907 uint32_t unit_address = hvcsd->vdev->unit_address; 908 struct list_head head; 909 int retval; 910 911 spin_lock(&hvcs_pi_lock); 912 if (!hvcs_pi_buff) { 913 spin_unlock(&hvcs_pi_lock); 914 return -EFAULT; 915 } 916 retval = hvcs_get_partner_info(unit_address, &head, hvcs_pi_buff); 917 spin_unlock(&hvcs_pi_lock); 918 if (retval) { 919 printk(KERN_ERR "HVCS: Failed to fetch partner" 920 " info for vty-server@%x.\n", unit_address); 921 return retval; 922 } 923 924 /* nixes the values if the partner vty went away */ 925 hvcsd->p_unit_address = 0; 926 hvcsd->p_partition_ID = 0; 927 928 list_for_each_entry(pi, &head, node) 929 hvcs_set_pi(pi, hvcsd); 930 931 hvcs_free_partner_info(&head); 932 return 0; 933 } 934 935 /* 936 * This function is executed by the driver "rescan" sysfs entry. It shouldn't 937 * be executed elsewhere, in order to prevent deadlock issues. 938 */ 939 static int hvcs_rescan_devices_list(void) 940 { 941 struct hvcs_struct *hvcsd; 942 unsigned long flags; 943 944 spin_lock(&hvcs_structs_lock); 945 946 list_for_each_entry(hvcsd, &hvcs_structs, next) { 947 spin_lock_irqsave(&hvcsd->lock, flags); 948 hvcs_get_pi(hvcsd); 949 spin_unlock_irqrestore(&hvcsd->lock, flags); 950 } 951 952 spin_unlock(&hvcs_structs_lock); 953 954 return 0; 955 } 956 957 /* 958 * Farm this off into its own function because it could be more complex once 959 * multiple partners support is added. This function should be called with 960 * the hvcsd->lock held. 961 */ 962 static int hvcs_has_pi(struct hvcs_struct *hvcsd) 963 { 964 if ((!hvcsd->p_unit_address) || (!hvcsd->p_partition_ID)) 965 return 0; 966 return 1; 967 } 968 969 /* 970 * NOTE: It is possible that the super admin removed a partner vty and then 971 * added a different vty as the new partner. 972 * 973 * This function must be called with the hvcsd->lock held. 974 */ 975 static int hvcs_partner_connect(struct hvcs_struct *hvcsd) 976 { 977 int retval; 978 unsigned int unit_address = hvcsd->vdev->unit_address; 979 980 /* 981 * If there wasn't any pi when the device was added it doesn't meant 982 * there isn't any now. This driver isn't notified when a new partner 983 * vty is added to a vty-server so we discover changes on our own. 984 * Please see comments in hvcs_register_connection() for justification 985 * of this bizarre code. 986 */ 987 retval = hvcs_register_connection(unit_address, 988 hvcsd->p_partition_ID, 989 hvcsd->p_unit_address); 990 if (!retval) { 991 hvcsd->connected = 1; 992 return 0; 993 } else if (retval != -EINVAL) 994 return retval; 995 996 /* 997 * As per the spec re-get the pi and try again if -EINVAL after the 998 * first connection attempt. 999 */ 1000 if (hvcs_get_pi(hvcsd)) 1001 return -ENOMEM; 1002 1003 if (!hvcs_has_pi(hvcsd)) 1004 return -ENODEV; 1005 1006 retval = hvcs_register_connection(unit_address, 1007 hvcsd->p_partition_ID, 1008 hvcsd->p_unit_address); 1009 if (retval != -EINVAL) { 1010 hvcsd->connected = 1; 1011 return retval; 1012 } 1013 1014 /* 1015 * EBUSY is the most likely scenario though the vty could have been 1016 * removed or there really could be an hcall error due to the parameter 1017 * data but thanks to ambiguous firmware return codes we can't really 1018 * tell. 1019 */ 1020 printk(KERN_INFO "HVCS: vty-server or partner" 1021 " vty is busy. Try again later.\n"); 1022 return -EBUSY; 1023 } 1024 1025 /* This function must be called with the hvcsd->lock held */ 1026 static void hvcs_partner_free(struct hvcs_struct *hvcsd) 1027 { 1028 int retval; 1029 do { 1030 retval = hvcs_free_connection(hvcsd->vdev->unit_address); 1031 } while (retval == -EBUSY); 1032 hvcsd->connected = 0; 1033 } 1034 1035 /* This helper function must be called WITHOUT the hvcsd->lock held */ 1036 static int hvcs_enable_device(struct hvcs_struct *hvcsd, uint32_t unit_address, 1037 unsigned int irq, struct vio_dev *vdev) 1038 { 1039 unsigned long flags; 1040 int rc; 1041 1042 /* 1043 * It is possible that the vty-server was removed between the time that 1044 * the conn was registered and now. 1045 */ 1046 rc = request_irq(irq, &hvcs_handle_interrupt, 0, "ibmhvcs", hvcsd); 1047 if (!rc) { 1048 /* 1049 * It is possible the vty-server was removed after the irq was 1050 * requested but before we have time to enable interrupts. 1051 */ 1052 if (vio_enable_interrupts(vdev) == H_SUCCESS) 1053 return 0; 1054 else { 1055 printk(KERN_ERR "HVCS: int enable failed for" 1056 " vty-server@%X.\n", unit_address); 1057 free_irq(irq, hvcsd); 1058 } 1059 } else 1060 printk(KERN_ERR "HVCS: irq req failed for" 1061 " vty-server@%X.\n", unit_address); 1062 1063 spin_lock_irqsave(&hvcsd->lock, flags); 1064 hvcs_partner_free(hvcsd); 1065 spin_unlock_irqrestore(&hvcsd->lock, flags); 1066 1067 return rc; 1068 1069 } 1070 1071 /* 1072 * This always increments the kref ref count if the call is successful. 1073 * Please remember to dec when you are done with the instance. 1074 * 1075 * NOTICE: Do NOT hold either the hvcs_struct.lock or hvcs_structs_lock when 1076 * calling this function or you will get deadlock. 1077 */ 1078 static struct hvcs_struct *hvcs_get_by_index(int index) 1079 { 1080 struct hvcs_struct *hvcsd; 1081 unsigned long flags; 1082 1083 spin_lock(&hvcs_structs_lock); 1084 list_for_each_entry(hvcsd, &hvcs_structs, next) { 1085 spin_lock_irqsave(&hvcsd->lock, flags); 1086 if (hvcsd->index == index) { 1087 tty_port_get(&hvcsd->port); 1088 spin_unlock_irqrestore(&hvcsd->lock, flags); 1089 spin_unlock(&hvcs_structs_lock); 1090 return hvcsd; 1091 } 1092 spin_unlock_irqrestore(&hvcsd->lock, flags); 1093 } 1094 spin_unlock(&hvcs_structs_lock); 1095 1096 return NULL; 1097 } 1098 1099 static int hvcs_install(struct tty_driver *driver, struct tty_struct *tty) 1100 { 1101 struct hvcs_struct *hvcsd; 1102 struct vio_dev *vdev; 1103 unsigned long unit_address, flags; 1104 unsigned int irq; 1105 int retval; 1106 1107 /* 1108 * Is there a vty-server that shares the same index? 1109 * This function increments the kref index. 1110 */ 1111 hvcsd = hvcs_get_by_index(tty->index); 1112 if (!hvcsd) { 1113 printk(KERN_WARNING "HVCS: open failed, no device associated" 1114 " with tty->index %d.\n", tty->index); 1115 return -ENODEV; 1116 } 1117 1118 spin_lock_irqsave(&hvcsd->lock, flags); 1119 1120 if (hvcsd->connected == 0) { 1121 retval = hvcs_partner_connect(hvcsd); 1122 if (retval) { 1123 spin_unlock_irqrestore(&hvcsd->lock, flags); 1124 printk(KERN_WARNING "HVCS: partner connect failed.\n"); 1125 goto err_put; 1126 } 1127 } 1128 1129 hvcsd->port.count = 0; 1130 hvcsd->port.tty = tty; 1131 tty->driver_data = hvcsd; 1132 1133 memset(&hvcsd->buffer[0], 0x00, HVCS_BUFF_LEN); 1134 1135 /* 1136 * Save these in the spinlock for the enable operations that need them 1137 * outside of the spinlock. 1138 */ 1139 irq = hvcsd->vdev->irq; 1140 vdev = hvcsd->vdev; 1141 unit_address = hvcsd->vdev->unit_address; 1142 1143 hvcsd->todo_mask |= HVCS_SCHED_READ; 1144 spin_unlock_irqrestore(&hvcsd->lock, flags); 1145 1146 /* 1147 * This must be done outside of the spinlock because it requests irqs 1148 * and will grab the spinlock and free the connection if it fails. 1149 */ 1150 retval = hvcs_enable_device(hvcsd, unit_address, irq, vdev); 1151 if (retval) { 1152 printk(KERN_WARNING "HVCS: enable device failed.\n"); 1153 goto err_put; 1154 } 1155 1156 retval = tty_port_install(&hvcsd->port, driver, tty); 1157 if (retval) 1158 goto err_irq; 1159 1160 return 0; 1161 err_irq: 1162 spin_lock_irqsave(&hvcsd->lock, flags); 1163 vio_disable_interrupts(hvcsd->vdev); 1164 spin_unlock_irqrestore(&hvcsd->lock, flags); 1165 free_irq(irq, hvcsd); 1166 err_put: 1167 tty_port_put(&hvcsd->port); 1168 1169 return retval; 1170 } 1171 1172 /* 1173 * This is invoked via the tty_open interface when a user app connects to the 1174 * /dev node. 1175 */ 1176 static int hvcs_open(struct tty_struct *tty, struct file *filp) 1177 { 1178 struct hvcs_struct *hvcsd = tty->driver_data; 1179 unsigned long flags; 1180 1181 spin_lock_irqsave(&hvcsd->lock, flags); 1182 hvcsd->port.count++; 1183 hvcsd->todo_mask |= HVCS_SCHED_READ; 1184 spin_unlock_irqrestore(&hvcsd->lock, flags); 1185 1186 hvcs_kick(); 1187 1188 printk(KERN_INFO "HVCS: vty-server@%X connection opened.\n", 1189 hvcsd->vdev->unit_address ); 1190 1191 return 0; 1192 } 1193 1194 static void hvcs_close(struct tty_struct *tty, struct file *filp) 1195 { 1196 struct hvcs_struct *hvcsd; 1197 unsigned long flags; 1198 int irq; 1199 1200 /* 1201 * Is someone trying to close the file associated with this device after 1202 * we have hung up? If so tty->driver_data wouldn't be valid. 1203 */ 1204 if (tty_hung_up_p(filp)) 1205 return; 1206 1207 /* 1208 * No driver_data means that this close was probably issued after a 1209 * failed hvcs_open by the tty layer's release_dev() api and we can just 1210 * exit cleanly. 1211 */ 1212 if (!tty->driver_data) 1213 return; 1214 1215 hvcsd = tty->driver_data; 1216 1217 spin_lock_irqsave(&hvcsd->lock, flags); 1218 if (--hvcsd->port.count == 0) { 1219 1220 vio_disable_interrupts(hvcsd->vdev); 1221 1222 /* 1223 * NULL this early so that the kernel_thread doesn't try to 1224 * execute any operations on the TTY even though it is obligated 1225 * to deliver any pending I/O to the hypervisor. 1226 */ 1227 hvcsd->port.tty = NULL; 1228 1229 irq = hvcsd->vdev->irq; 1230 spin_unlock_irqrestore(&hvcsd->lock, flags); 1231 1232 tty_wait_until_sent(tty, HVCS_CLOSE_WAIT); 1233 1234 /* 1235 * This line is important because it tells hvcs_open that this 1236 * device needs to be re-configured the next time hvcs_open is 1237 * called. 1238 */ 1239 tty->driver_data = NULL; 1240 1241 free_irq(irq, hvcsd); 1242 return; 1243 } else if (hvcsd->port.count < 0) { 1244 printk(KERN_ERR "HVCS: vty-server@%X open_count: %d is mismanaged.\n", 1245 hvcsd->vdev->unit_address, hvcsd->port.count); 1246 } 1247 1248 spin_unlock_irqrestore(&hvcsd->lock, flags); 1249 } 1250 1251 static void hvcs_cleanup(struct tty_struct * tty) 1252 { 1253 struct hvcs_struct *hvcsd = tty->driver_data; 1254 1255 tty_port_put(&hvcsd->port); 1256 } 1257 1258 static void hvcs_hangup(struct tty_struct * tty) 1259 { 1260 struct hvcs_struct *hvcsd = tty->driver_data; 1261 unsigned long flags; 1262 int temp_open_count; 1263 int irq; 1264 1265 spin_lock_irqsave(&hvcsd->lock, flags); 1266 /* Preserve this so that we know how many kref refs to put */ 1267 temp_open_count = hvcsd->port.count; 1268 1269 /* 1270 * Don't kref put inside the spinlock because the destruction 1271 * callback may use the spinlock and it may get called before the 1272 * spinlock has been released. 1273 */ 1274 vio_disable_interrupts(hvcsd->vdev); 1275 1276 hvcsd->todo_mask = 0; 1277 1278 /* I don't think the tty needs the hvcs_struct pointer after a hangup */ 1279 tty->driver_data = NULL; 1280 hvcsd->port.tty = NULL; 1281 1282 hvcsd->port.count = 0; 1283 1284 /* This will drop any buffered data on the floor which is OK in a hangup 1285 * scenario. */ 1286 memset(&hvcsd->buffer[0], 0x00, HVCS_BUFF_LEN); 1287 hvcsd->chars_in_buffer = 0; 1288 1289 irq = hvcsd->vdev->irq; 1290 1291 spin_unlock_irqrestore(&hvcsd->lock, flags); 1292 1293 free_irq(irq, hvcsd); 1294 1295 /* 1296 * We need to kref_put() for every open_count we have since the 1297 * tty_hangup() function doesn't invoke a close per open connection on a 1298 * non-console device. 1299 */ 1300 while(temp_open_count) { 1301 --temp_open_count; 1302 /* 1303 * The final put will trigger destruction of the hvcs_struct. 1304 * NOTE: If this hangup was signaled from user space then the 1305 * final put will never happen. 1306 */ 1307 tty_port_put(&hvcsd->port); 1308 } 1309 } 1310 1311 /* 1312 * NOTE: This is almost always from_user since user level apps interact with the 1313 * /dev nodes. I'm trusting that if hvcs_write gets called and interrupted by 1314 * hvcs_remove (which removes the target device and executes tty_hangup()) that 1315 * tty_hangup will allow hvcs_write time to complete execution before it 1316 * terminates our device. 1317 */ 1318 static int hvcs_write(struct tty_struct *tty, 1319 const unsigned char *buf, int count) 1320 { 1321 struct hvcs_struct *hvcsd = tty->driver_data; 1322 unsigned int unit_address; 1323 const unsigned char *charbuf; 1324 unsigned long flags; 1325 int total_sent = 0; 1326 int tosend = 0; 1327 int result = 0; 1328 1329 /* 1330 * If they don't check the return code off of their open they may 1331 * attempt this even if there is no connected device. 1332 */ 1333 if (!hvcsd) 1334 return -ENODEV; 1335 1336 /* Reasonable size to prevent user level flooding */ 1337 if (count > HVCS_MAX_FROM_USER) { 1338 printk(KERN_WARNING "HVCS write: count being truncated to" 1339 " HVCS_MAX_FROM_USER.\n"); 1340 count = HVCS_MAX_FROM_USER; 1341 } 1342 1343 charbuf = buf; 1344 1345 spin_lock_irqsave(&hvcsd->lock, flags); 1346 1347 /* 1348 * Somehow an open succeeded but the device was removed or the 1349 * connection terminated between the vty-server and partner vty during 1350 * the middle of a write operation? This is a crummy place to do this 1351 * but we want to keep it all in the spinlock. 1352 */ 1353 if (hvcsd->port.count <= 0) { 1354 spin_unlock_irqrestore(&hvcsd->lock, flags); 1355 return -ENODEV; 1356 } 1357 1358 unit_address = hvcsd->vdev->unit_address; 1359 1360 while (count > 0) { 1361 tosend = min(count, (HVCS_BUFF_LEN - hvcsd->chars_in_buffer)); 1362 /* 1363 * No more space, this probably means that the last call to 1364 * hvcs_write() didn't succeed and the buffer was filled up. 1365 */ 1366 if (!tosend) 1367 break; 1368 1369 memcpy(&hvcsd->buffer[hvcsd->chars_in_buffer], 1370 &charbuf[total_sent], 1371 tosend); 1372 1373 hvcsd->chars_in_buffer += tosend; 1374 1375 result = 0; 1376 1377 /* 1378 * If this is true then we don't want to try writing to the 1379 * hypervisor because that is the kernel_threads job now. We'll 1380 * just add to the buffer. 1381 */ 1382 if (!(hvcsd->todo_mask & HVCS_TRY_WRITE)) 1383 /* won't send partial writes */ 1384 result = hvc_put_chars(unit_address, 1385 &hvcsd->buffer[0], 1386 hvcsd->chars_in_buffer); 1387 1388 /* 1389 * Since we know we have enough room in hvcsd->buffer for 1390 * tosend we record that it was sent regardless of whether the 1391 * hypervisor actually took it because we have it buffered. 1392 */ 1393 total_sent+=tosend; 1394 count-=tosend; 1395 if (result == 0) { 1396 hvcsd->todo_mask |= HVCS_TRY_WRITE; 1397 hvcs_kick(); 1398 break; 1399 } 1400 1401 hvcsd->chars_in_buffer = 0; 1402 /* 1403 * Test after the chars_in_buffer reset otherwise this could 1404 * deadlock our writes if hvc_put_chars fails. 1405 */ 1406 if (result < 0) 1407 break; 1408 } 1409 1410 spin_unlock_irqrestore(&hvcsd->lock, flags); 1411 1412 if (result == -1) 1413 return -EIO; 1414 else 1415 return total_sent; 1416 } 1417 1418 /* 1419 * This is really asking how much can we guarantee that we can send or that we 1420 * absolutely WILL BUFFER if we can't send it. This driver MUST honor the 1421 * return value, hence the reason for hvcs_struct buffering. 1422 */ 1423 static int hvcs_write_room(struct tty_struct *tty) 1424 { 1425 struct hvcs_struct *hvcsd = tty->driver_data; 1426 1427 if (!hvcsd || hvcsd->port.count <= 0) 1428 return 0; 1429 1430 return HVCS_BUFF_LEN - hvcsd->chars_in_buffer; 1431 } 1432 1433 static int hvcs_chars_in_buffer(struct tty_struct *tty) 1434 { 1435 struct hvcs_struct *hvcsd = tty->driver_data; 1436 1437 return hvcsd->chars_in_buffer; 1438 } 1439 1440 static const struct tty_operations hvcs_ops = { 1441 .install = hvcs_install, 1442 .open = hvcs_open, 1443 .close = hvcs_close, 1444 .cleanup = hvcs_cleanup, 1445 .hangup = hvcs_hangup, 1446 .write = hvcs_write, 1447 .write_room = hvcs_write_room, 1448 .chars_in_buffer = hvcs_chars_in_buffer, 1449 .unthrottle = hvcs_unthrottle, 1450 .throttle = hvcs_throttle, 1451 }; 1452 1453 static int hvcs_alloc_index_list(int n) 1454 { 1455 int i; 1456 1457 hvcs_index_list = kmalloc(n * sizeof(hvcs_index_count),GFP_KERNEL); 1458 if (!hvcs_index_list) 1459 return -ENOMEM; 1460 hvcs_index_count = n; 1461 for (i = 0; i < hvcs_index_count; i++) 1462 hvcs_index_list[i] = -1; 1463 return 0; 1464 } 1465 1466 static void hvcs_free_index_list(void) 1467 { 1468 /* Paranoia check to be thorough. */ 1469 kfree(hvcs_index_list); 1470 hvcs_index_list = NULL; 1471 hvcs_index_count = 0; 1472 } 1473 1474 static int hvcs_initialize(void) 1475 { 1476 int rc, num_ttys_to_alloc; 1477 1478 mutex_lock(&hvcs_init_mutex); 1479 if (hvcs_task) { 1480 mutex_unlock(&hvcs_init_mutex); 1481 return 0; 1482 } 1483 1484 /* Has the user specified an overload with an insmod param? */ 1485 if (hvcs_parm_num_devs <= 0 || 1486 (hvcs_parm_num_devs > HVCS_MAX_SERVER_ADAPTERS)) { 1487 num_ttys_to_alloc = HVCS_DEFAULT_SERVER_ADAPTERS; 1488 } else 1489 num_ttys_to_alloc = hvcs_parm_num_devs; 1490 1491 hvcs_tty_driver = alloc_tty_driver(num_ttys_to_alloc); 1492 if (!hvcs_tty_driver) { 1493 mutex_unlock(&hvcs_init_mutex); 1494 return -ENOMEM; 1495 } 1496 1497 if (hvcs_alloc_index_list(num_ttys_to_alloc)) { 1498 rc = -ENOMEM; 1499 goto index_fail; 1500 } 1501 1502 hvcs_tty_driver->driver_name = hvcs_driver_name; 1503 hvcs_tty_driver->name = hvcs_device_node; 1504 1505 /* 1506 * We'll let the system assign us a major number, indicated by leaving 1507 * it blank. 1508 */ 1509 1510 hvcs_tty_driver->minor_start = HVCS_MINOR_START; 1511 hvcs_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM; 1512 1513 /* 1514 * We role our own so that we DONT ECHO. We can't echo because the 1515 * device we are connecting to already echoes by default and this would 1516 * throw us into a horrible recursive echo-echo-echo loop. 1517 */ 1518 hvcs_tty_driver->init_termios = hvcs_tty_termios; 1519 hvcs_tty_driver->flags = TTY_DRIVER_REAL_RAW; 1520 1521 tty_set_operations(hvcs_tty_driver, &hvcs_ops); 1522 1523 /* 1524 * The following call will result in sysfs entries that denote the 1525 * dynamically assigned major and minor numbers for our devices. 1526 */ 1527 if (tty_register_driver(hvcs_tty_driver)) { 1528 printk(KERN_ERR "HVCS: registration as a tty driver failed.\n"); 1529 rc = -EIO; 1530 goto register_fail; 1531 } 1532 1533 hvcs_pi_buff = (unsigned long *) __get_free_page(GFP_KERNEL); 1534 if (!hvcs_pi_buff) { 1535 rc = -ENOMEM; 1536 goto buff_alloc_fail; 1537 } 1538 1539 hvcs_task = kthread_run(khvcsd, NULL, "khvcsd"); 1540 if (IS_ERR(hvcs_task)) { 1541 printk(KERN_ERR "HVCS: khvcsd creation failed.\n"); 1542 rc = -EIO; 1543 goto kthread_fail; 1544 } 1545 mutex_unlock(&hvcs_init_mutex); 1546 return 0; 1547 1548 kthread_fail: 1549 free_page((unsigned long)hvcs_pi_buff); 1550 buff_alloc_fail: 1551 tty_unregister_driver(hvcs_tty_driver); 1552 register_fail: 1553 hvcs_free_index_list(); 1554 index_fail: 1555 put_tty_driver(hvcs_tty_driver); 1556 hvcs_tty_driver = NULL; 1557 mutex_unlock(&hvcs_init_mutex); 1558 return rc; 1559 } 1560 1561 static int __init hvcs_module_init(void) 1562 { 1563 int rc = vio_register_driver(&hvcs_vio_driver); 1564 if (rc) { 1565 printk(KERN_ERR "HVCS: can't register vio driver\n"); 1566 return rc; 1567 } 1568 1569 pr_info("HVCS: Driver registered.\n"); 1570 1571 /* This needs to be done AFTER the vio_register_driver() call or else 1572 * the kobjects won't be initialized properly. 1573 */ 1574 rc = driver_create_file(&(hvcs_vio_driver.driver), &driver_attr_rescan); 1575 if (rc) 1576 pr_warn("HVCS: Failed to create rescan file (err %d)\n", rc); 1577 1578 return 0; 1579 } 1580 1581 static void __exit hvcs_module_exit(void) 1582 { 1583 /* 1584 * This driver receives hvcs_remove callbacks for each device upon 1585 * module removal. 1586 */ 1587 vio_unregister_driver(&hvcs_vio_driver); 1588 if (!hvcs_task) 1589 return; 1590 1591 /* 1592 * This synchronous operation will wake the khvcsd kthread if it is 1593 * asleep and will return when khvcsd has terminated. 1594 */ 1595 kthread_stop(hvcs_task); 1596 1597 spin_lock(&hvcs_pi_lock); 1598 free_page((unsigned long)hvcs_pi_buff); 1599 hvcs_pi_buff = NULL; 1600 spin_unlock(&hvcs_pi_lock); 1601 1602 driver_remove_file(&hvcs_vio_driver.driver, &driver_attr_rescan); 1603 1604 tty_unregister_driver(hvcs_tty_driver); 1605 1606 hvcs_free_index_list(); 1607 1608 put_tty_driver(hvcs_tty_driver); 1609 1610 printk(KERN_INFO "HVCS: driver module removed.\n"); 1611 } 1612 1613 module_init(hvcs_module_init); 1614 module_exit(hvcs_module_exit); 1615