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 <asm/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 similarily 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 130MODULE_AUTHOR("Ryan S. Arnold <rsa@us.ibm.com>"); 131MODULE_DESCRIPTION("IBM hvcs (Hypervisor Virtual Console Server) Driver"); 132MODULE_LICENSE("GPL"); 133MODULE_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 */ 192static 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 */ 207static int hvcs_parm_num_devs = -1; 208module_param(hvcs_parm_num_devs, int, 0); 209 210static const char hvcs_driver_name[] = "hvcs"; 211static const char hvcs_device_node[] = "hvcs"; 212static const char hvcs_driver_string[] 213 = "IBM hvcs (Hypervisor Virtual Console Server) Driver"; 214 215/* Status of partner info rescan triggered via sysfs. */ 216static int hvcs_rescan_status; 217 218static 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 */ 233static 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 */ 239static 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 */ 245static 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 */ 251static 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 */ 257static unsigned long *hvcs_pi_buff; 258 259/* Only allow one hvcs_struct to use the hvcs_pi_buff at a time. */ 260static DEFINE_SPINLOCK(hvcs_pi_lock); 261 262/* One vty-server per hvcs_struct */ 263struct hvcs_struct { 264 spinlock_t lock; 265 266 /* 267 * This index identifies this hvcs device as the complement to a 268 * specific tty index. 269 */ 270 unsigned int index; 271 272 struct tty_struct *tty; 273 int open_count; 274 275 /* 276 * Used to tell the driver kernel_thread what operations need to take 277 * place upon this hvcs_struct instance. 278 */ 279 int todo_mask; 280 281 /* 282 * This buffer is required so that when hvcs_write_room() reports that 283 * it can send HVCS_BUFF_LEN characters that it will buffer the full 284 * HVCS_BUFF_LEN characters if need be. This is essential for opost 285 * writes since they do not do high level buffering and expect to be 286 * able to send what the driver commits to sending buffering 287 * [e.g. tab to space conversions in n_tty.c opost()]. 288 */ 289 char buffer[HVCS_BUFF_LEN]; 290 int chars_in_buffer; 291 292 /* 293 * Any variable below the kref is valid before a tty is connected and 294 * stays valid after the tty is disconnected. These shouldn't be 295 * whacked until the koject refcount reaches zero though some entries 296 * may be changed via sysfs initiatives. 297 */ 298 struct kref kref; /* ref count & hvcs_struct lifetime */ 299 int connected; /* is the vty-server currently connected to a vty? */ 300 uint32_t p_unit_address; /* partner unit address */ 301 uint32_t p_partition_ID; /* partner partition ID */ 302 char p_location_code[HVCS_CLC_LENGTH + 1]; /* CLC + Null Term */ 303 struct list_head next; /* list management */ 304 struct vio_dev *vdev; 305}; 306 307/* Required to back map a kref to its containing object */ 308#define from_kref(k) container_of(k, struct hvcs_struct, kref) 309 310static LIST_HEAD(hvcs_structs); 311static DEFINE_SPINLOCK(hvcs_structs_lock); 312 313static void hvcs_unthrottle(struct tty_struct *tty); 314static void hvcs_throttle(struct tty_struct *tty); 315static irqreturn_t hvcs_handle_interrupt(int irq, void *dev_instance); 316 317static int hvcs_write(struct tty_struct *tty, 318 const unsigned char *buf, int count); 319static int hvcs_write_room(struct tty_struct *tty); 320static int hvcs_chars_in_buffer(struct tty_struct *tty); 321 322static int hvcs_has_pi(struct hvcs_struct *hvcsd); 323static void hvcs_set_pi(struct hvcs_partner_info *pi, 324 struct hvcs_struct *hvcsd); 325static int hvcs_get_pi(struct hvcs_struct *hvcsd); 326static int hvcs_rescan_devices_list(void); 327 328static int hvcs_partner_connect(struct hvcs_struct *hvcsd); 329static void hvcs_partner_free(struct hvcs_struct *hvcsd); 330 331static int hvcs_enable_device(struct hvcs_struct *hvcsd, 332 uint32_t unit_address, unsigned int irq, struct vio_dev *dev); 333 334static int hvcs_open(struct tty_struct *tty, struct file *filp); 335static void hvcs_close(struct tty_struct *tty, struct file *filp); 336static void hvcs_hangup(struct tty_struct * tty); 337 338static int __devinit hvcs_probe(struct vio_dev *dev, 339 const struct vio_device_id *id); 340static int __devexit hvcs_remove(struct vio_dev *dev); 341static int __init hvcs_module_init(void); 342static void __exit hvcs_module_exit(void); 343 344#define HVCS_SCHED_READ 0x00000001 345#define HVCS_QUICK_READ 0x00000002 346#define HVCS_TRY_WRITE 0x00000004 347#define HVCS_READ_MASK (HVCS_SCHED_READ | HVCS_QUICK_READ) 348 349static inline struct hvcs_struct *from_vio_dev(struct vio_dev *viod) 350{ 351 return dev_get_drvdata(&viod->dev); 352} 353/* The sysfs interface for the driver and devices */ 354 355static ssize_t hvcs_partner_vtys_show(struct device *dev, struct device_attribute *attr, char *buf) 356{ 357 struct vio_dev *viod = to_vio_dev(dev); 358 struct hvcs_struct *hvcsd = from_vio_dev(viod); 359 unsigned long flags; 360 int retval; 361 362 spin_lock_irqsave(&hvcsd->lock, flags); 363 retval = sprintf(buf, "%X\n", hvcsd->p_unit_address); 364 spin_unlock_irqrestore(&hvcsd->lock, flags); 365 return retval; 366} 367static DEVICE_ATTR(partner_vtys, S_IRUGO, hvcs_partner_vtys_show, NULL); 368 369static ssize_t hvcs_partner_clcs_show(struct device *dev, struct device_attribute *attr, char *buf) 370{ 371 struct vio_dev *viod = to_vio_dev(dev); 372 struct hvcs_struct *hvcsd = from_vio_dev(viod); 373 unsigned long flags; 374 int retval; 375 376 spin_lock_irqsave(&hvcsd->lock, flags); 377 retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]); 378 spin_unlock_irqrestore(&hvcsd->lock, flags); 379 return retval; 380} 381static DEVICE_ATTR(partner_clcs, S_IRUGO, hvcs_partner_clcs_show, NULL); 382 383static ssize_t hvcs_current_vty_store(struct device *dev, struct device_attribute *attr, const char * buf, 384 size_t count) 385{ 386 /* 387 * Don't need this feature at the present time because firmware doesn't 388 * yet support multiple partners. 389 */ 390 printk(KERN_INFO "HVCS: Denied current_vty change: -EPERM.\n"); 391 return -EPERM; 392} 393 394static ssize_t hvcs_current_vty_show(struct device *dev, struct device_attribute *attr, char *buf) 395{ 396 struct vio_dev *viod = to_vio_dev(dev); 397 struct hvcs_struct *hvcsd = from_vio_dev(viod); 398 unsigned long flags; 399 int retval; 400 401 spin_lock_irqsave(&hvcsd->lock, flags); 402 retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]); 403 spin_unlock_irqrestore(&hvcsd->lock, flags); 404 return retval; 405} 406 407static DEVICE_ATTR(current_vty, 408 S_IRUGO | S_IWUSR, hvcs_current_vty_show, hvcs_current_vty_store); 409 410static ssize_t hvcs_vterm_state_store(struct device *dev, struct device_attribute *attr, const char *buf, 411 size_t count) 412{ 413 struct vio_dev *viod = to_vio_dev(dev); 414 struct hvcs_struct *hvcsd = from_vio_dev(viod); 415 unsigned long flags; 416 417 /* writing a '0' to this sysfs entry will result in the disconnect. */ 418 if (simple_strtol(buf, NULL, 0) != 0) 419 return -EINVAL; 420 421 spin_lock_irqsave(&hvcsd->lock, flags); 422 423 if (hvcsd->open_count > 0) { 424 spin_unlock_irqrestore(&hvcsd->lock, flags); 425 printk(KERN_INFO "HVCS: vterm state unchanged. " 426 "The hvcs device node is still in use.\n"); 427 return -EPERM; 428 } 429 430 if (hvcsd->connected == 0) { 431 spin_unlock_irqrestore(&hvcsd->lock, flags); 432 printk(KERN_INFO "HVCS: vterm state unchanged. The" 433 " vty-server is not connected to a vty.\n"); 434 return -EPERM; 435 } 436 437 hvcs_partner_free(hvcsd); 438 printk(KERN_INFO "HVCS: Closed vty-server@%X and" 439 " partner vty@%X:%d connection.\n", 440 hvcsd->vdev->unit_address, 441 hvcsd->p_unit_address, 442 (uint32_t)hvcsd->p_partition_ID); 443 444 spin_unlock_irqrestore(&hvcsd->lock, flags); 445 return count; 446} 447 448static ssize_t hvcs_vterm_state_show(struct device *dev, struct device_attribute *attr, char *buf) 449{ 450 struct vio_dev *viod = to_vio_dev(dev); 451 struct hvcs_struct *hvcsd = from_vio_dev(viod); 452 unsigned long flags; 453 int retval; 454 455 spin_lock_irqsave(&hvcsd->lock, flags); 456 retval = sprintf(buf, "%d\n", hvcsd->connected); 457 spin_unlock_irqrestore(&hvcsd->lock, flags); 458 return retval; 459} 460static DEVICE_ATTR(vterm_state, S_IRUGO | S_IWUSR, 461 hvcs_vterm_state_show, hvcs_vterm_state_store); 462 463static ssize_t hvcs_index_show(struct device *dev, struct device_attribute *attr, char *buf) 464{ 465 struct vio_dev *viod = to_vio_dev(dev); 466 struct hvcs_struct *hvcsd = from_vio_dev(viod); 467 unsigned long flags; 468 int retval; 469 470 spin_lock_irqsave(&hvcsd->lock, flags); 471 retval = sprintf(buf, "%d\n", hvcsd->index); 472 spin_unlock_irqrestore(&hvcsd->lock, flags); 473 return retval; 474} 475 476static DEVICE_ATTR(index, S_IRUGO, hvcs_index_show, NULL); 477 478static struct attribute *hvcs_attrs[] = { 479 &dev_attr_partner_vtys.attr, 480 &dev_attr_partner_clcs.attr, 481 &dev_attr_current_vty.attr, 482 &dev_attr_vterm_state.attr, 483 &dev_attr_index.attr, 484 NULL, 485}; 486 487static struct attribute_group hvcs_attr_group = { 488 .attrs = hvcs_attrs, 489}; 490 491static ssize_t hvcs_rescan_show(struct device_driver *ddp, char *buf) 492{ 493 /* A 1 means it is updating, a 0 means it is done updating */ 494 return snprintf(buf, PAGE_SIZE, "%d\n", hvcs_rescan_status); 495} 496 497static ssize_t hvcs_rescan_store(struct device_driver *ddp, const char * buf, 498 size_t count) 499{ 500 if ((simple_strtol(buf, NULL, 0) != 1) 501 && (hvcs_rescan_status != 0)) 502 return -EINVAL; 503 504 hvcs_rescan_status = 1; 505 printk(KERN_INFO "HVCS: rescanning partner info for all" 506 " vty-servers.\n"); 507 hvcs_rescan_devices_list(); 508 hvcs_rescan_status = 0; 509 return count; 510} 511 512static DRIVER_ATTR(rescan, 513 S_IRUGO | S_IWUSR, hvcs_rescan_show, hvcs_rescan_store); 514 515static void hvcs_kick(void) 516{ 517 hvcs_kicked = 1; 518 wmb(); 519 wake_up_process(hvcs_task); 520} 521 522static void hvcs_unthrottle(struct tty_struct *tty) 523{ 524 struct hvcs_struct *hvcsd = tty->driver_data; 525 unsigned long flags; 526 527 spin_lock_irqsave(&hvcsd->lock, flags); 528 hvcsd->todo_mask |= HVCS_SCHED_READ; 529 spin_unlock_irqrestore(&hvcsd->lock, flags); 530 hvcs_kick(); 531} 532 533static void hvcs_throttle(struct tty_struct *tty) 534{ 535 struct hvcs_struct *hvcsd = tty->driver_data; 536 unsigned long flags; 537 538 spin_lock_irqsave(&hvcsd->lock, flags); 539 vio_disable_interrupts(hvcsd->vdev); 540 spin_unlock_irqrestore(&hvcsd->lock, flags); 541} 542 543/* 544 * If the device is being removed we don't have to worry about this interrupt 545 * handler taking any further interrupts because they are disabled which means 546 * the hvcs_struct will always be valid in this handler. 547 */ 548static irqreturn_t hvcs_handle_interrupt(int irq, void *dev_instance) 549{ 550 struct hvcs_struct *hvcsd = dev_instance; 551 552 spin_lock(&hvcsd->lock); 553 vio_disable_interrupts(hvcsd->vdev); 554 hvcsd->todo_mask |= HVCS_SCHED_READ; 555 spin_unlock(&hvcsd->lock); 556 hvcs_kick(); 557 558 return IRQ_HANDLED; 559} 560 561/* This function must be called with the hvcsd->lock held */ 562static void hvcs_try_write(struct hvcs_struct *hvcsd) 563{ 564 uint32_t unit_address = hvcsd->vdev->unit_address; 565 struct tty_struct *tty = hvcsd->tty; 566 int sent; 567 568 if (hvcsd->todo_mask & HVCS_TRY_WRITE) { 569 /* won't send partial writes */ 570 sent = hvc_put_chars(unit_address, 571 &hvcsd->buffer[0], 572 hvcsd->chars_in_buffer ); 573 if (sent > 0) { 574 hvcsd->chars_in_buffer = 0; 575 /* wmb(); */ 576 hvcsd->todo_mask &= ~(HVCS_TRY_WRITE); 577 /* wmb(); */ 578 579 /* 580 * We are still obligated to deliver the data to the 581 * hypervisor even if the tty has been closed because 582 * we commited to delivering it. But don't try to wake 583 * a non-existent tty. 584 */ 585 if (tty) { 586 tty_wakeup(tty); 587 } 588 } 589 } 590} 591 592static int hvcs_io(struct hvcs_struct *hvcsd) 593{ 594 uint32_t unit_address; 595 struct tty_struct *tty; 596 char buf[HVCS_BUFF_LEN] __ALIGNED__; 597 unsigned long flags; 598 int got = 0; 599 600 spin_lock_irqsave(&hvcsd->lock, flags); 601 602 unit_address = hvcsd->vdev->unit_address; 603 tty = hvcsd->tty; 604 605 hvcs_try_write(hvcsd); 606 607 if (!tty || test_bit(TTY_THROTTLED, &tty->flags)) { 608 hvcsd->todo_mask &= ~(HVCS_READ_MASK); 609 goto bail; 610 } else if (!(hvcsd->todo_mask & (HVCS_READ_MASK))) 611 goto bail; 612 613 /* remove the read masks */ 614 hvcsd->todo_mask &= ~(HVCS_READ_MASK); 615 616 if (tty_buffer_request_room(tty, HVCS_BUFF_LEN) >= HVCS_BUFF_LEN) { 617 got = hvc_get_chars(unit_address, 618 &buf[0], 619 HVCS_BUFF_LEN); 620 tty_insert_flip_string(tty, buf, got); 621 } 622 623 /* Give the TTY time to process the data we just sent. */ 624 if (got) 625 hvcsd->todo_mask |= HVCS_QUICK_READ; 626 627 spin_unlock_irqrestore(&hvcsd->lock, flags); 628 /* This is synch because tty->low_latency == 1 */ 629 if(got) 630 tty_flip_buffer_push(tty); 631 632 if (!got) { 633 /* Do this _after_ the flip_buffer_push */ 634 spin_lock_irqsave(&hvcsd->lock, flags); 635 vio_enable_interrupts(hvcsd->vdev); 636 spin_unlock_irqrestore(&hvcsd->lock, flags); 637 } 638 639 return hvcsd->todo_mask; 640 641 bail: 642 spin_unlock_irqrestore(&hvcsd->lock, flags); 643 return hvcsd->todo_mask; 644} 645 646static int khvcsd(void *unused) 647{ 648 struct hvcs_struct *hvcsd; 649 int hvcs_todo_mask; 650 651 __set_current_state(TASK_RUNNING); 652 653 do { 654 hvcs_todo_mask = 0; 655 hvcs_kicked = 0; 656 wmb(); 657 658 spin_lock(&hvcs_structs_lock); 659 list_for_each_entry(hvcsd, &hvcs_structs, next) { 660 hvcs_todo_mask |= hvcs_io(hvcsd); 661 } 662 spin_unlock(&hvcs_structs_lock); 663 664 /* 665 * If any of the hvcs adapters want to try a write or quick read 666 * don't schedule(), yield a smidgen then execute the hvcs_io 667 * thread again for those that want the write. 668 */ 669 if (hvcs_todo_mask & (HVCS_TRY_WRITE | HVCS_QUICK_READ)) { 670 yield(); 671 continue; 672 } 673 674 set_current_state(TASK_INTERRUPTIBLE); 675 if (!hvcs_kicked) 676 schedule(); 677 __set_current_state(TASK_RUNNING); 678 } while (!kthread_should_stop()); 679 680 return 0; 681} 682 683static struct vio_device_id hvcs_driver_table[] __devinitdata= { 684 {"serial-server", "hvterm2"}, 685 { "", "" } 686}; 687MODULE_DEVICE_TABLE(vio, hvcs_driver_table); 688 689static void hvcs_return_index(int index) 690{ 691 /* Paranoia check */ 692 if (!hvcs_index_list) 693 return; 694 if (index < 0 || index >= hvcs_index_count) 695 return; 696 if (hvcs_index_list[index] == -1) 697 return; 698 else 699 hvcs_index_list[index] = -1; 700} 701 702/* callback when the kref ref count reaches zero */ 703static void destroy_hvcs_struct(struct kref *kref) 704{ 705 struct hvcs_struct *hvcsd = from_kref(kref); 706 struct vio_dev *vdev; 707 unsigned long flags; 708 709 spin_lock(&hvcs_structs_lock); 710 spin_lock_irqsave(&hvcsd->lock, flags); 711 712 /* the list_del poisons the pointers */ 713 list_del(&(hvcsd->next)); 714 715 if (hvcsd->connected == 1) { 716 hvcs_partner_free(hvcsd); 717 printk(KERN_INFO "HVCS: Closed vty-server@%X and" 718 " partner vty@%X:%d connection.\n", 719 hvcsd->vdev->unit_address, 720 hvcsd->p_unit_address, 721 (uint32_t)hvcsd->p_partition_ID); 722 } 723 printk(KERN_INFO "HVCS: Destroyed hvcs_struct for vty-server@%X.\n", 724 hvcsd->vdev->unit_address); 725 726 vdev = hvcsd->vdev; 727 hvcsd->vdev = NULL; 728 729 hvcsd->p_unit_address = 0; 730 hvcsd->p_partition_ID = 0; 731 hvcs_return_index(hvcsd->index); 732 memset(&hvcsd->p_location_code[0], 0x00, HVCS_CLC_LENGTH + 1); 733 734 spin_unlock_irqrestore(&hvcsd->lock, flags); 735 spin_unlock(&hvcs_structs_lock); 736 737 sysfs_remove_group(&vdev->dev.kobj, &hvcs_attr_group); 738 739 kfree(hvcsd); 740} 741 742static int hvcs_get_index(void) 743{ 744 int i; 745 /* Paranoia check */ 746 if (!hvcs_index_list) { 747 printk(KERN_ERR "HVCS: hvcs_index_list NOT valid!.\n"); 748 return -EFAULT; 749 } 750 /* Find the numerically lowest first free index. */ 751 for(i = 0; i < hvcs_index_count; i++) { 752 if (hvcs_index_list[i] == -1) { 753 hvcs_index_list[i] = 0; 754 return i; 755 } 756 } 757 return -1; 758} 759 760static int __devinit hvcs_probe( 761 struct vio_dev *dev, 762 const struct vio_device_id *id) 763{ 764 struct hvcs_struct *hvcsd; 765 int index; 766 int retval; 767 768 if (!dev || !id) { 769 printk(KERN_ERR "HVCS: probed with invalid parameter.\n"); 770 return -EPERM; 771 } 772 773 /* early to avoid cleanup on failure */ 774 index = hvcs_get_index(); 775 if (index < 0) { 776 return -EFAULT; 777 } 778 779 hvcsd = kzalloc(sizeof(*hvcsd), GFP_KERNEL); 780 if (!hvcsd) 781 return -ENODEV; 782 783 784 spin_lock_init(&hvcsd->lock); 785 /* Automatically incs the refcount the first time */ 786 kref_init(&hvcsd->kref); 787 788 hvcsd->vdev = dev; 789 dev_set_drvdata(&dev->dev, hvcsd); 790 791 hvcsd->index = index; 792 793 /* hvcsd->index = ++hvcs_struct_count; */ 794 hvcsd->chars_in_buffer = 0; 795 hvcsd->todo_mask = 0; 796 hvcsd->connected = 0; 797 798 /* 799 * This will populate the hvcs_struct's partner info fields for the 800 * first time. 801 */ 802 if (hvcs_get_pi(hvcsd)) { 803 printk(KERN_ERR "HVCS: Failed to fetch partner" 804 " info for vty-server@%X on device probe.\n", 805 hvcsd->vdev->unit_address); 806 } 807 808 /* 809 * If a user app opens a tty that corresponds to this vty-server before 810 * the hvcs_struct has been added to the devices list then the user app 811 * will get -ENODEV. 812 */ 813 spin_lock(&hvcs_structs_lock); 814 list_add_tail(&(hvcsd->next), &hvcs_structs); 815 spin_unlock(&hvcs_structs_lock); 816 817 retval = sysfs_create_group(&dev->dev.kobj, &hvcs_attr_group); 818 if (retval) { 819 printk(KERN_ERR "HVCS: Can't create sysfs attrs for vty-server@%X\n", 820 hvcsd->vdev->unit_address); 821 return retval; 822 } 823 824 printk(KERN_INFO "HVCS: vty-server@%X added to the vio bus.\n", dev->unit_address); 825 826 /* 827 * DON'T enable interrupts here because there is no user to receive the 828 * data. 829 */ 830 return 0; 831} 832 833static int __devexit hvcs_remove(struct vio_dev *dev) 834{ 835 struct hvcs_struct *hvcsd = dev_get_drvdata(&dev->dev); 836 unsigned long flags; 837 struct tty_struct *tty; 838 839 if (!hvcsd) 840 return -ENODEV; 841 842 /* By this time the vty-server won't be getting any more interrupts */ 843 844 spin_lock_irqsave(&hvcsd->lock, flags); 845 846 tty = hvcsd->tty; 847 848 spin_unlock_irqrestore(&hvcsd->lock, flags); 849 850 /* 851 * Let the last holder of this object cause it to be removed, which 852 * would probably be tty_hangup below. 853 */ 854 kref_put(&hvcsd->kref, destroy_hvcs_struct); 855 856 /* 857 * The hangup is a scheduled function which will auto chain call 858 * hvcs_hangup. The tty should always be valid at this time unless a 859 * simultaneous tty close already cleaned up the hvcs_struct. 860 */ 861 if (tty) 862 tty_hangup(tty); 863 864 printk(KERN_INFO "HVCS: vty-server@%X removed from the" 865 " vio bus.\n", dev->unit_address); 866 return 0; 867}; 868 869static struct vio_driver hvcs_vio_driver = { 870 .id_table = hvcs_driver_table, 871 .probe = hvcs_probe, 872 .remove = __devexit_p(hvcs_remove), 873 .driver = { 874 .name = hvcs_driver_name, 875 .owner = THIS_MODULE, 876 } 877}; 878 879/* Only called from hvcs_get_pi please */ 880static void hvcs_set_pi(struct hvcs_partner_info *pi, struct hvcs_struct *hvcsd) 881{ 882 int clclength; 883 884 hvcsd->p_unit_address = pi->unit_address; 885 hvcsd->p_partition_ID = pi->partition_ID; 886 clclength = strlen(&pi->location_code[0]); 887 if (clclength > HVCS_CLC_LENGTH) 888 clclength = HVCS_CLC_LENGTH; 889 890 /* copy the null-term char too */ 891 strncpy(&hvcsd->p_location_code[0], 892 &pi->location_code[0], clclength + 1); 893} 894 895/* 896 * Traverse the list and add the partner info that is found to the hvcs_struct 897 * struct entry. NOTE: At this time I know that partner info will return a 898 * single entry but in the future there may be multiple partner info entries per 899 * vty-server and you'll want to zero out that list and reset it. If for some 900 * reason you have an old version of this driver but there IS more than one 901 * partner info then hvcsd->p_* will hold the last partner info data from the 902 * firmware query. A good way to update this code would be to replace the three 903 * partner info fields in hvcs_struct with a list of hvcs_partner_info 904 * instances. 905 * 906 * This function must be called with the hvcsd->lock held. 907 */ 908static int hvcs_get_pi(struct hvcs_struct *hvcsd) 909{ 910 struct hvcs_partner_info *pi; 911 uint32_t unit_address = hvcsd->vdev->unit_address; 912 struct list_head head; 913 int retval; 914 915 spin_lock(&hvcs_pi_lock); 916 if (!hvcs_pi_buff) { 917 spin_unlock(&hvcs_pi_lock); 918 return -EFAULT; 919 } 920 retval = hvcs_get_partner_info(unit_address, &head, hvcs_pi_buff); 921 spin_unlock(&hvcs_pi_lock); 922 if (retval) { 923 printk(KERN_ERR "HVCS: Failed to fetch partner" 924 " info for vty-server@%x.\n", unit_address); 925 return retval; 926 } 927 928 /* nixes the values if the partner vty went away */ 929 hvcsd->p_unit_address = 0; 930 hvcsd->p_partition_ID = 0; 931 932 list_for_each_entry(pi, &head, node) 933 hvcs_set_pi(pi, hvcsd); 934 935 hvcs_free_partner_info(&head); 936 return 0; 937} 938 939/* 940 * This function is executed by the driver "rescan" sysfs entry. It shouldn't 941 * be executed elsewhere, in order to prevent deadlock issues. 942 */ 943static int hvcs_rescan_devices_list(void) 944{ 945 struct hvcs_struct *hvcsd; 946 unsigned long flags; 947 948 spin_lock(&hvcs_structs_lock); 949 950 list_for_each_entry(hvcsd, &hvcs_structs, next) { 951 spin_lock_irqsave(&hvcsd->lock, flags); 952 hvcs_get_pi(hvcsd); 953 spin_unlock_irqrestore(&hvcsd->lock, flags); 954 } 955 956 spin_unlock(&hvcs_structs_lock); 957 958 return 0; 959} 960 961/* 962 * Farm this off into its own function because it could be more complex once 963 * multiple partners support is added. This function should be called with 964 * the hvcsd->lock held. 965 */ 966static int hvcs_has_pi(struct hvcs_struct *hvcsd) 967{ 968 if ((!hvcsd->p_unit_address) || (!hvcsd->p_partition_ID)) 969 return 0; 970 return 1; 971} 972 973/* 974 * NOTE: It is possible that the super admin removed a partner vty and then 975 * added a different vty as the new partner. 976 * 977 * This function must be called with the hvcsd->lock held. 978 */ 979static int hvcs_partner_connect(struct hvcs_struct *hvcsd) 980{ 981 int retval; 982 unsigned int unit_address = hvcsd->vdev->unit_address; 983 984 /* 985 * If there wasn't any pi when the device was added it doesn't meant 986 * there isn't any now. This driver isn't notified when a new partner 987 * vty is added to a vty-server so we discover changes on our own. 988 * Please see comments in hvcs_register_connection() for justification 989 * of this bizarre code. 990 */ 991 retval = hvcs_register_connection(unit_address, 992 hvcsd->p_partition_ID, 993 hvcsd->p_unit_address); 994 if (!retval) { 995 hvcsd->connected = 1; 996 return 0; 997 } else if (retval != -EINVAL) 998 return retval; 999 1000 /* 1001 * As per the spec re-get the pi and try again if -EINVAL after the 1002 * first connection attempt. 1003 */ 1004 if (hvcs_get_pi(hvcsd)) 1005 return -ENOMEM; 1006 1007 if (!hvcs_has_pi(hvcsd)) 1008 return -ENODEV; 1009 1010 retval = hvcs_register_connection(unit_address, 1011 hvcsd->p_partition_ID, 1012 hvcsd->p_unit_address); 1013 if (retval != -EINVAL) { 1014 hvcsd->connected = 1; 1015 return retval; 1016 } 1017 1018 /* 1019 * EBUSY is the most likely scenario though the vty could have been 1020 * removed or there really could be an hcall error due to the parameter 1021 * data but thanks to ambiguous firmware return codes we can't really 1022 * tell. 1023 */ 1024 printk(KERN_INFO "HVCS: vty-server or partner" 1025 " vty is busy. Try again later.\n"); 1026 return -EBUSY; 1027} 1028 1029/* This function must be called with the hvcsd->lock held */ 1030static void hvcs_partner_free(struct hvcs_struct *hvcsd) 1031{ 1032 int retval; 1033 do { 1034 retval = hvcs_free_connection(hvcsd->vdev->unit_address); 1035 } while (retval == -EBUSY); 1036 hvcsd->connected = 0; 1037} 1038 1039/* This helper function must be called WITHOUT the hvcsd->lock held */ 1040static int hvcs_enable_device(struct hvcs_struct *hvcsd, uint32_t unit_address, 1041 unsigned int irq, struct vio_dev *vdev) 1042{ 1043 unsigned long flags; 1044 int rc; 1045 1046 /* 1047 * It is possible that the vty-server was removed between the time that 1048 * the conn was registered and now. 1049 */ 1050 if (!(rc = request_irq(irq, &hvcs_handle_interrupt, 1051 IRQF_DISABLED, "ibmhvcs", hvcsd))) { 1052 /* 1053 * It is possible the vty-server was removed after the irq was 1054 * requested but before we have time to enable interrupts. 1055 */ 1056 if (vio_enable_interrupts(vdev) == H_SUCCESS) 1057 return 0; 1058 else { 1059 printk(KERN_ERR "HVCS: int enable failed for" 1060 " vty-server@%X.\n", unit_address); 1061 free_irq(irq, hvcsd); 1062 } 1063 } else 1064 printk(KERN_ERR "HVCS: irq req failed for" 1065 " vty-server@%X.\n", unit_address); 1066 1067 spin_lock_irqsave(&hvcsd->lock, flags); 1068 hvcs_partner_free(hvcsd); 1069 spin_unlock_irqrestore(&hvcsd->lock, flags); 1070 1071 return rc; 1072 1073} 1074 1075/* 1076 * This always increments the kref ref count if the call is successful. 1077 * Please remember to dec when you are done with the instance. 1078 * 1079 * NOTICE: Do NOT hold either the hvcs_struct.lock or hvcs_structs_lock when 1080 * calling this function or you will get deadlock. 1081 */ 1082static struct hvcs_struct *hvcs_get_by_index(int index) 1083{ 1084 struct hvcs_struct *hvcsd = NULL; 1085 unsigned long flags; 1086 1087 spin_lock(&hvcs_structs_lock); 1088 /* We can immediately discard OOB requests */ 1089 if (index >= 0 && index < HVCS_MAX_SERVER_ADAPTERS) { 1090 list_for_each_entry(hvcsd, &hvcs_structs, next) { 1091 spin_lock_irqsave(&hvcsd->lock, flags); 1092 if (hvcsd->index == index) { 1093 kref_get(&hvcsd->kref); 1094 spin_unlock_irqrestore(&hvcsd->lock, flags); 1095 spin_unlock(&hvcs_structs_lock); 1096 return hvcsd; 1097 } 1098 spin_unlock_irqrestore(&hvcsd->lock, flags); 1099 } 1100 hvcsd = NULL; 1101 } 1102 1103 spin_unlock(&hvcs_structs_lock); 1104 return hvcsd; 1105} 1106 1107/* 1108 * This is invoked via the tty_open interface when a user app connects to the 1109 * /dev node. 1110 */ 1111static int hvcs_open(struct tty_struct *tty, struct file *filp) 1112{ 1113 struct hvcs_struct *hvcsd; 1114 int rc, retval = 0; 1115 unsigned long flags; 1116 unsigned int irq; 1117 struct vio_dev *vdev; 1118 unsigned long unit_address; 1119 1120 if (tty->driver_data) 1121 goto fast_open; 1122 1123 /* 1124 * Is there a vty-server that shares the same index? 1125 * This function increments the kref index. 1126 */ 1127 if (!(hvcsd = hvcs_get_by_index(tty->index))) { 1128 printk(KERN_WARNING "HVCS: open failed, no device associated" 1129 " with tty->index %d.\n", tty->index); 1130 return -ENODEV; 1131 } 1132 1133 spin_lock_irqsave(&hvcsd->lock, flags); 1134 1135 if (hvcsd->connected == 0) 1136 if ((retval = hvcs_partner_connect(hvcsd))) 1137 goto error_release; 1138 1139 hvcsd->open_count = 1; 1140 hvcsd->tty = tty; 1141 tty->driver_data = hvcsd; 1142 1143 memset(&hvcsd->buffer[0], 0x00, HVCS_BUFF_LEN); 1144 1145 /* 1146 * Save these in the spinlock for the enable operations that need them 1147 * outside of the spinlock. 1148 */ 1149 irq = hvcsd->vdev->irq; 1150 vdev = hvcsd->vdev; 1151 unit_address = hvcsd->vdev->unit_address; 1152 1153 hvcsd->todo_mask |= HVCS_SCHED_READ; 1154 spin_unlock_irqrestore(&hvcsd->lock, flags); 1155 1156 /* 1157 * This must be done outside of the spinlock because it requests irqs 1158 * and will grab the spinlock and free the connection if it fails. 1159 */ 1160 if (((rc = hvcs_enable_device(hvcsd, unit_address, irq, vdev)))) { 1161 kref_put(&hvcsd->kref, destroy_hvcs_struct); 1162 printk(KERN_WARNING "HVCS: enable device failed.\n"); 1163 return rc; 1164 } 1165 1166 goto open_success; 1167 1168fast_open: 1169 hvcsd = tty->driver_data; 1170 1171 spin_lock_irqsave(&hvcsd->lock, flags); 1172 kref_get(&hvcsd->kref); 1173 hvcsd->open_count++; 1174 hvcsd->todo_mask |= HVCS_SCHED_READ; 1175 spin_unlock_irqrestore(&hvcsd->lock, flags); 1176 1177open_success: 1178 hvcs_kick(); 1179 1180 printk(KERN_INFO "HVCS: vty-server@%X connection opened.\n", 1181 hvcsd->vdev->unit_address ); 1182 1183 return 0; 1184 1185error_release: 1186 spin_unlock_irqrestore(&hvcsd->lock, flags); 1187 kref_put(&hvcsd->kref, destroy_hvcs_struct); 1188 1189 printk(KERN_WARNING "HVCS: partner connect failed.\n"); 1190 return retval; 1191} 1192 1193static void hvcs_close(struct tty_struct *tty, struct file *filp) 1194{ 1195 struct hvcs_struct *hvcsd; 1196 unsigned long flags; 1197 int irq = NO_IRQ; 1198 1199 /* 1200 * Is someone trying to close the file associated with this device after 1201 * we have hung up? If so tty->driver_data wouldn't be valid. 1202 */ 1203 if (tty_hung_up_p(filp)) 1204 return; 1205 1206 /* 1207 * No driver_data means that this close was probably issued after a 1208 * failed hvcs_open by the tty layer's release_dev() api and we can just 1209 * exit cleanly. 1210 */ 1211 if (!tty->driver_data) 1212 return; 1213 1214 hvcsd = tty->driver_data; 1215 1216 spin_lock_irqsave(&hvcsd->lock, flags); 1217 if (--hvcsd->open_count == 0) { 1218 1219 vio_disable_interrupts(hvcsd->vdev); 1220 1221 /* 1222 * NULL this early so that the kernel_thread doesn't try to 1223 * execute any operations on the TTY even though it is obligated 1224 * to deliver any pending I/O to the hypervisor. 1225 */ 1226 hvcsd->tty = NULL; 1227 1228 irq = hvcsd->vdev->irq; 1229 spin_unlock_irqrestore(&hvcsd->lock, flags); 1230 1231 tty_wait_until_sent(tty, HVCS_CLOSE_WAIT); 1232 1233 /* 1234 * This line is important because it tells hvcs_open that this 1235 * device needs to be re-configured the next time hvcs_open is 1236 * called. 1237 */ 1238 tty->driver_data = NULL; 1239 1240 free_irq(irq, hvcsd); 1241 kref_put(&hvcsd->kref, destroy_hvcs_struct); 1242 return; 1243 } else if (hvcsd->open_count < 0) { 1244 printk(KERN_ERR "HVCS: vty-server@%X open_count: %d" 1245 " is missmanaged.\n", 1246 hvcsd->vdev->unit_address, hvcsd->open_count); 1247 } 1248 1249 spin_unlock_irqrestore(&hvcsd->lock, flags); 1250 kref_put(&hvcsd->kref, destroy_hvcs_struct); 1251} 1252 1253static void hvcs_hangup(struct tty_struct * tty) 1254{ 1255 struct hvcs_struct *hvcsd = tty->driver_data; 1256 unsigned long flags; 1257 int temp_open_count; 1258 int irq = NO_IRQ; 1259 1260 spin_lock_irqsave(&hvcsd->lock, flags); 1261 /* Preserve this so that we know how many kref refs to put */ 1262 temp_open_count = hvcsd->open_count; 1263 1264 /* 1265 * Don't kref put inside the spinlock because the destruction 1266 * callback may use the spinlock and it may get called before the 1267 * spinlock has been released. 1268 */ 1269 vio_disable_interrupts(hvcsd->vdev); 1270 1271 hvcsd->todo_mask = 0; 1272 1273 /* I don't think the tty needs the hvcs_struct pointer after a hangup */ 1274 hvcsd->tty->driver_data = NULL; 1275 hvcsd->tty = NULL; 1276 1277 hvcsd->open_count = 0; 1278 1279 /* This will drop any buffered data on the floor which is OK in a hangup 1280 * scenario. */ 1281 memset(&hvcsd->buffer[0], 0x00, HVCS_BUFF_LEN); 1282 hvcsd->chars_in_buffer = 0; 1283 1284 irq = hvcsd->vdev->irq; 1285 1286 spin_unlock_irqrestore(&hvcsd->lock, flags); 1287 1288 free_irq(irq, hvcsd); 1289 1290 /* 1291 * We need to kref_put() for every open_count we have since the 1292 * tty_hangup() function doesn't invoke a close per open connection on a 1293 * non-console device. 1294 */ 1295 while(temp_open_count) { 1296 --temp_open_count; 1297 /* 1298 * The final put will trigger destruction of the hvcs_struct. 1299 * NOTE: If this hangup was signaled from user space then the 1300 * final put will never happen. 1301 */ 1302 kref_put(&hvcsd->kref, destroy_hvcs_struct); 1303 } 1304} 1305 1306/* 1307 * NOTE: This is almost always from_user since user level apps interact with the 1308 * /dev nodes. I'm trusting that if hvcs_write gets called and interrupted by 1309 * hvcs_remove (which removes the target device and executes tty_hangup()) that 1310 * tty_hangup will allow hvcs_write time to complete execution before it 1311 * terminates our device. 1312 */ 1313static int hvcs_write(struct tty_struct *tty, 1314 const unsigned char *buf, int count) 1315{ 1316 struct hvcs_struct *hvcsd = tty->driver_data; 1317 unsigned int unit_address; 1318 const unsigned char *charbuf; 1319 unsigned long flags; 1320 int total_sent = 0; 1321 int tosend = 0; 1322 int result = 0; 1323 1324 /* 1325 * If they don't check the return code off of their open they may 1326 * attempt this even if there is no connected device. 1327 */ 1328 if (!hvcsd) 1329 return -ENODEV; 1330 1331 /* Reasonable size to prevent user level flooding */ 1332 if (count > HVCS_MAX_FROM_USER) { 1333 printk(KERN_WARNING "HVCS write: count being truncated to" 1334 " HVCS_MAX_FROM_USER.\n"); 1335 count = HVCS_MAX_FROM_USER; 1336 } 1337 1338 charbuf = buf; 1339 1340 spin_lock_irqsave(&hvcsd->lock, flags); 1341 1342 /* 1343 * Somehow an open succedded but the device was removed or the 1344 * connection terminated between the vty-server and partner vty during 1345 * the middle of a write operation? This is a crummy place to do this 1346 * but we want to keep it all in the spinlock. 1347 */ 1348 if (hvcsd->open_count <= 0) { 1349 spin_unlock_irqrestore(&hvcsd->lock, flags); 1350 return -ENODEV; 1351 } 1352 1353 unit_address = hvcsd->vdev->unit_address; 1354 1355 while (count > 0) { 1356 tosend = min(count, (HVCS_BUFF_LEN - hvcsd->chars_in_buffer)); 1357 /* 1358 * No more space, this probably means that the last call to 1359 * hvcs_write() didn't succeed and the buffer was filled up. 1360 */ 1361 if (!tosend) 1362 break; 1363 1364 memcpy(&hvcsd->buffer[hvcsd->chars_in_buffer], 1365 &charbuf[total_sent], 1366 tosend); 1367 1368 hvcsd->chars_in_buffer += tosend; 1369 1370 result = 0; 1371 1372 /* 1373 * If this is true then we don't want to try writing to the 1374 * hypervisor because that is the kernel_threads job now. We'll 1375 * just add to the buffer. 1376 */ 1377 if (!(hvcsd->todo_mask & HVCS_TRY_WRITE)) 1378 /* won't send partial writes */ 1379 result = hvc_put_chars(unit_address, 1380 &hvcsd->buffer[0], 1381 hvcsd->chars_in_buffer); 1382 1383 /* 1384 * Since we know we have enough room in hvcsd->buffer for 1385 * tosend we record that it was sent regardless of whether the 1386 * hypervisor actually took it because we have it buffered. 1387 */ 1388 total_sent+=tosend; 1389 count-=tosend; 1390 if (result == 0) { 1391 hvcsd->todo_mask |= HVCS_TRY_WRITE; 1392 hvcs_kick(); 1393 break; 1394 } 1395 1396 hvcsd->chars_in_buffer = 0; 1397 /* 1398 * Test after the chars_in_buffer reset otherwise this could 1399 * deadlock our writes if hvc_put_chars fails. 1400 */ 1401 if (result < 0) 1402 break; 1403 } 1404 1405 spin_unlock_irqrestore(&hvcsd->lock, flags); 1406 1407 if (result == -1) 1408 return -EIO; 1409 else 1410 return total_sent; 1411} 1412 1413/* 1414 * This is really asking how much can we guarentee that we can send or that we 1415 * absolutely WILL BUFFER if we can't send it. This driver MUST honor the 1416 * return value, hence the reason for hvcs_struct buffering. 1417 */ 1418static int hvcs_write_room(struct tty_struct *tty) 1419{ 1420 struct hvcs_struct *hvcsd = tty->driver_data; 1421 1422 if (!hvcsd || hvcsd->open_count <= 0) 1423 return 0; 1424 1425 return HVCS_BUFF_LEN - hvcsd->chars_in_buffer; 1426} 1427 1428static int hvcs_chars_in_buffer(struct tty_struct *tty) 1429{ 1430 struct hvcs_struct *hvcsd = tty->driver_data; 1431 1432 return hvcsd->chars_in_buffer; 1433} 1434 1435static const struct tty_operations hvcs_ops = { 1436 .open = hvcs_open, 1437 .close = hvcs_close, 1438 .hangup = hvcs_hangup, 1439 .write = hvcs_write, 1440 .write_room = hvcs_write_room, 1441 .chars_in_buffer = hvcs_chars_in_buffer, 1442 .unthrottle = hvcs_unthrottle, 1443 .throttle = hvcs_throttle, 1444}; 1445 1446static int hvcs_alloc_index_list(int n) 1447{ 1448 int i; 1449 1450 hvcs_index_list = kmalloc(n * sizeof(hvcs_index_count),GFP_KERNEL); 1451 if (!hvcs_index_list) 1452 return -ENOMEM; 1453 hvcs_index_count = n; 1454 for (i = 0; i < hvcs_index_count; i++) 1455 hvcs_index_list[i] = -1; 1456 return 0; 1457} 1458 1459static void hvcs_free_index_list(void) 1460{ 1461 /* Paranoia check to be thorough. */ 1462 kfree(hvcs_index_list); 1463 hvcs_index_list = NULL; 1464 hvcs_index_count = 0; 1465} 1466 1467static int __init hvcs_module_init(void) 1468{ 1469 int rc; 1470 int num_ttys_to_alloc; 1471 1472 printk(KERN_INFO "Initializing %s\n", hvcs_driver_string); 1473 1474 /* Has the user specified an overload with an insmod param? */ 1475 if (hvcs_parm_num_devs <= 0 || 1476 (hvcs_parm_num_devs > HVCS_MAX_SERVER_ADAPTERS)) { 1477 num_ttys_to_alloc = HVCS_DEFAULT_SERVER_ADAPTERS; 1478 } else 1479 num_ttys_to_alloc = hvcs_parm_num_devs; 1480 1481 hvcs_tty_driver = alloc_tty_driver(num_ttys_to_alloc); 1482 if (!hvcs_tty_driver) 1483 return -ENOMEM; 1484 1485 if (hvcs_alloc_index_list(num_ttys_to_alloc)) { 1486 rc = -ENOMEM; 1487 goto index_fail; 1488 } 1489 1490 hvcs_tty_driver->owner = THIS_MODULE; 1491 1492 hvcs_tty_driver->driver_name = hvcs_driver_name; 1493 hvcs_tty_driver->name = hvcs_device_node; 1494 1495 /* 1496 * We'll let the system assign us a major number, indicated by leaving 1497 * it blank. 1498 */ 1499 1500 hvcs_tty_driver->minor_start = HVCS_MINOR_START; 1501 hvcs_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM; 1502 1503 /* 1504 * We role our own so that we DONT ECHO. We can't echo because the 1505 * device we are connecting to already echoes by default and this would 1506 * throw us into a horrible recursive echo-echo-echo loop. 1507 */ 1508 hvcs_tty_driver->init_termios = hvcs_tty_termios; 1509 hvcs_tty_driver->flags = TTY_DRIVER_REAL_RAW; 1510 1511 tty_set_operations(hvcs_tty_driver, &hvcs_ops); 1512 1513 /* 1514 * The following call will result in sysfs entries that denote the 1515 * dynamically assigned major and minor numbers for our devices. 1516 */ 1517 if (tty_register_driver(hvcs_tty_driver)) { 1518 printk(KERN_ERR "HVCS: registration as a tty driver failed.\n"); 1519 rc = -EIO; 1520 goto register_fail; 1521 } 1522 1523 hvcs_pi_buff = kmalloc(PAGE_SIZE, GFP_KERNEL); 1524 if (!hvcs_pi_buff) { 1525 rc = -ENOMEM; 1526 goto buff_alloc_fail; 1527 } 1528 1529 hvcs_task = kthread_run(khvcsd, NULL, "khvcsd"); 1530 if (IS_ERR(hvcs_task)) { 1531 printk(KERN_ERR "HVCS: khvcsd creation failed. Driver not loaded.\n"); 1532 rc = -EIO; 1533 goto kthread_fail; 1534 } 1535 1536 rc = vio_register_driver(&hvcs_vio_driver); 1537 if (rc) { 1538 printk(KERN_ERR "HVCS: can't register vio driver\n"); 1539 goto vio_fail; 1540 } 1541 1542 /* 1543 * This needs to be done AFTER the vio_register_driver() call or else 1544 * the kobjects won't be initialized properly. 1545 */ 1546 rc = driver_create_file(&(hvcs_vio_driver.driver), &driver_attr_rescan); 1547 if (rc) { 1548 printk(KERN_ERR "HVCS: sysfs attr create failed\n"); 1549 goto attr_fail; 1550 } 1551 1552 printk(KERN_INFO "HVCS: driver module inserted.\n"); 1553 1554 return 0; 1555 1556attr_fail: 1557 vio_unregister_driver(&hvcs_vio_driver); 1558vio_fail: 1559 kthread_stop(hvcs_task); 1560kthread_fail: 1561 kfree(hvcs_pi_buff); 1562buff_alloc_fail: 1563 tty_unregister_driver(hvcs_tty_driver); 1564register_fail: 1565 hvcs_free_index_list(); 1566index_fail: 1567 put_tty_driver(hvcs_tty_driver); 1568 hvcs_tty_driver = NULL; 1569 return rc; 1570} 1571 1572static void __exit hvcs_module_exit(void) 1573{ 1574 /* 1575 * This driver receives hvcs_remove callbacks for each device upon 1576 * module removal. 1577 */ 1578 1579 /* 1580 * This synchronous operation will wake the khvcsd kthread if it is 1581 * asleep and will return when khvcsd has terminated. 1582 */ 1583 kthread_stop(hvcs_task); 1584 1585 spin_lock(&hvcs_pi_lock); 1586 kfree(hvcs_pi_buff); 1587 hvcs_pi_buff = NULL; 1588 spin_unlock(&hvcs_pi_lock); 1589 1590 driver_remove_file(&hvcs_vio_driver.driver, &driver_attr_rescan); 1591 1592 vio_unregister_driver(&hvcs_vio_driver); 1593 1594 tty_unregister_driver(hvcs_tty_driver); 1595 1596 hvcs_free_index_list(); 1597 1598 put_tty_driver(hvcs_tty_driver); 1599 1600 printk(KERN_INFO "HVCS: driver module removed.\n"); 1601} 1602 1603module_init(hvcs_module_init); 1604module_exit(hvcs_module_exit); 1605