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1// SPDX-License-Identifier: GPL-2.0+2/*3 * IBM eServer Hypervisor Virtual Console Server Device Driver4 * Copyright (C) 2003, 2004 IBM Corp.5 * Ryan S. Arnold (rsa@us.ibm.com)6 *7 * Author(s) : Ryan S. Arnold <rsa@us.ibm.com>8 *9 * This is the device driver for the IBM Hypervisor Virtual Console Server,10 * "hvcs". The IBM hvcs provides a tty driver interface to allow Linux11 * user space applications access to the system consoles of logically12 * partitioned operating systems, e.g. Linux, running on the same partitioned13 * Power5 ppc64 system. Physical hardware consoles per partition are not14 * practical on this hardware so system consoles are accessed by this driver15 * using inter-partition firmware interfaces to virtual terminal devices.16 *17 * A vty is known to the HMC as a "virtual serial server adapter". It is a18 * virtual terminal device that is created by firmware upon partition creation19 * to act as a partitioned OS's console device.20 *21 * Firmware dynamically (via hotplug) exposes vty-servers to a running ppc6422 * Linux system upon their creation by the HMC or their exposure during boot.23 * The non-user interactive backend of this driver is implemented as a vio24 * device driver so that it can receive notification of vty-server lifetimes25 * after it registers with the vio bus to handle vty-server probe and remove26 * callbacks.27 *28 * Many vty-servers can be configured to connect to one vty, but a vty can29 * only be actively connected to by a single vty-server, in any manner, at one30 * time. If the HMC is currently hosting the console for a target Linux31 * partition; attempts to open the tty device to the partition's console using32 * the hvcs on any partition will return -EBUSY with every open attempt until33 * the HMC frees the connection between its vty-server and the desired34 * partition's vty device. Conversely, a vty-server may only be connected to35 * a single vty at one time even though it may have several configured vty36 * partner possibilities.37 *38 * Firmware does not provide notification of vty partner changes to this39 * driver. This means that an HMC Super Admin may add or remove partner vtys40 * from a vty-server's partner list but the changes will not be signaled to41 * the vty-server. Firmware only notifies the driver when a vty-server is42 * added or removed from the system. To compensate for this deficiency, this43 * driver implements a sysfs update attribute which provides a method for44 * rescanning partner information upon a user's request.45 *46 * Each vty-server, prior to being exposed to this driver is reference counted47 * using the 2.6 Linux kernel kref construct.48 *49 * For direction on installation and usage of this driver please reference50 * Documentation/arch/powerpc/hvcs.rst.51 */52 53#include <linux/device.h>54#include <linux/init.h>55#include <linux/completion.h>56#include <linux/interrupt.h>57#include <linux/kernel.h>58#include <linux/kref.h>59#include <linux/kthread.h>60#include <linux/list.h>61#include <linux/major.h>62#include <linux/module.h>63#include <linux/moduleparam.h>64#include <linux/sched.h>65#include <linux/slab.h>66#include <linux/spinlock.h>67#include <linux/stat.h>68#include <linux/tty.h>69#include <linux/tty_flip.h>70#include <asm/hvconsole.h>71#include <asm/hvcserver.h>72#include <linux/uaccess.h>73#include <linux/termios_internal.h>74#include <asm/vio.h>75 76/*77 * 1.3.0 -> 1.3.1 In hvcs_open memset(..,0x00,..) instead of memset(..,0x3F,00).78 * Removed braces around single statements following conditionals. Removed '=79 * 0' after static int declarations since these default to zero. Removed80 * list_for_each_safe() and replaced with list_for_each_entry() in81 * hvcs_get_by_index(). The 'safe' version is un-needed now that the driver is82 * using spinlocks. Changed spin_lock_irqsave() to spin_lock() when locking83 * hvcs_structs_lock and hvcs_pi_lock since these are not touched in an int84 * handler. Initialized hvcs_structs_lock and hvcs_pi_lock to85 * SPIN_LOCK_UNLOCKED at declaration time rather than in hvcs_module_init().86 * Added spin_lock around list_del() in destroy_hvcs_struct() to protect the87 * list traversals from a deletion. Removed '= NULL' from pointer declaration88 * statements since they are initialized NULL by default. Removed wmb()89 * instances from hvcs_try_write(). They probably aren't needed with locking in90 * place. Added check and cleanup for hvcs_pi_buff = kmalloc() in91 * hvcs_module_init(). Exposed hvcs_struct.index via a sysfs attribute so that92 * the coupling between /dev/hvcs* and a vty-server can be automatically93 * determined. Moved kobject_put() in hvcs_open outside of the94 * spin_unlock_irqrestore().95 *96 * 1.3.1 -> 1.3.2 Changed method for determining hvcs_struct->index and had it97 * align with how the tty layer always assigns the lowest index available. This98 * change resulted in a list of ints that denotes which indexes are available.99 * Device additions and removals use the new hvcs_get_index() and100 * hvcs_return_index() helper functions. The list is created with101 * hvsc_alloc_index_list() and it is destroyed with hvcs_free_index_list().102 * Without these fixes hotplug vty-server adapter support goes crazy with this103 * driver if the user removes a vty-server adapter. Moved free_irq() outside of104 * the hvcs_final_close() function in order to get it out of the spinlock.105 * Rearranged hvcs_close(). Cleaned up some printks and did some housekeeping106 * on the changelog. Removed local CLC_LENGTH and used HVCS_CLC_LENGTH from107 * arch/powerepc/include/asm/hvcserver.h108 *109 * 1.3.2 -> 1.3.3 Replaced yield() in hvcs_close() with tty_wait_until_sent() to110 * prevent possible lockup with realtime scheduling as similarly pointed out by111 * akpm in hvc_console. Changed resulted in the removal of hvcs_final_close()112 * to reorder cleanup operations and prevent discarding of pending data during113 * an hvcs_close(). Removed spinlock protection of hvcs_struct data members in114 * hvcs_write_room() and hvcs_chars_in_buffer() because they aren't needed.115 */116 117#define HVCS_DRIVER_VERSION "1.3.3"118 119MODULE_AUTHOR("Ryan S. Arnold <rsa@us.ibm.com>");120MODULE_DESCRIPTION("IBM hvcs (Hypervisor Virtual Console Server) Driver");121MODULE_LICENSE("GPL");122MODULE_VERSION(HVCS_DRIVER_VERSION);123 124/*125 * Wait this long per iteration while trying to push buffered data to the126 * hypervisor before allowing the tty to complete a close operation.127 */128#define HVCS_CLOSE_WAIT (HZ/100) /* 1/10 of a second */129 130/*131 * Since the Linux TTY code does not currently (2-04-2004) support dynamic132 * addition of tty derived devices and we shouldn't allocate thousands of133 * tty_device pointers when the number of vty-server & vty partner connections134 * will most often be much lower than this, we'll arbitrarily allocate135 * HVCS_DEFAULT_SERVER_ADAPTERS tty_structs and cdev's by default when we136 * register the tty_driver. This can be overridden using an insmod parameter.137 */138#define HVCS_DEFAULT_SERVER_ADAPTERS 64139 140/*141 * The user can't insmod with more than HVCS_MAX_SERVER_ADAPTERS hvcs device142 * nodes as a sanity check. Theoretically there can be over 1 Billion143 * vty-server & vty partner connections.144 */145#define HVCS_MAX_SERVER_ADAPTERS 1024146 147/*148 * We let Linux assign us a major number and we start the minors at zero. There149 * is no intuitive mapping between minor number and the target vty-server150 * adapter except that each new vty-server adapter is always assigned to the151 * smallest minor number available.152 */153#define HVCS_MINOR_START 0154 155/*156 * The hcall interface involves putting 8 chars into each of two registers.157 * We load up those 2 registers (in arch/powerpc/platforms/pseries/hvconsole.c)158 * by casting char[16] to long[2]. It would work without __ALIGNED__, but a 159 * little (tiny) bit slower because an unaligned load is slower than aligned 160 * load.161 */162#define __ALIGNED__ __attribute__((__aligned__(8)))163 164/*165 * How much data can firmware send with each hvc_put_chars()? Maybe this166 * should be moved into an architecture specific area.167 */168#define HVCS_BUFF_LEN 16169 170/*171 * This is the maximum amount of data we'll let the user send us (hvcs_write) at172 * once in a chunk as a sanity check.173 */174#define HVCS_MAX_FROM_USER 4096175 176/*177 * Be careful when adding flags to this line discipline. Don't add anything178 * that will cause echoing or we'll go into recursive loop echoing chars back179 * and forth with the console drivers.180 */181static const struct ktermios hvcs_tty_termios = {182 .c_iflag = IGNBRK | IGNPAR,183 .c_oflag = OPOST,184 .c_cflag = B38400 | CS8 | CREAD | HUPCL,185 .c_cc = INIT_C_CC,186 .c_ispeed = 38400,187 .c_ospeed = 38400188};189 190/*191 * This value is used to take the place of a command line parameter when the192 * module is inserted. It starts as -1 and stays as such if the user doesn't193 * specify a module insmod parameter. If they DO specify one then it is set to194 * the value of the integer passed in.195 */196static int hvcs_parm_num_devs = -1;197module_param(hvcs_parm_num_devs, int, 0);198 199static const char hvcs_driver_name[] = "hvcs";200static const char hvcs_device_node[] = "hvcs";201 202/* Status of partner info rescan triggered via sysfs. */203static int hvcs_rescan_status;204 205static struct tty_driver *hvcs_tty_driver;206 207/*208 * In order to be somewhat sane this driver always associates the hvcs_struct209 * index element with the numerically equal tty->index. This means that a210 * hotplugged vty-server adapter will always map to the lowest index valued211 * device node. If vty-servers were hotplug removed from the system and then212 * new ones added the new vty-server may have the largest slot number of all213 * the vty-server adapters in the partition but it may have the lowest dev node214 * index of all the adapters due to the hole left by the hotplug removed215 * adapter. There are a set of functions provided to get the lowest index for216 * a new device as well as return the index to the list. This list is allocated217 * with a number of elements equal to the number of device nodes requested when218 * the module was inserted.219 */220static int *hvcs_index_list;221 222/*223 * How large is the list? This is kept for traversal since the list is224 * dynamically created.225 */226static int hvcs_index_count;227 228/*229 * Used by the khvcsd to pick up I/O operations when the kernel_thread is230 * already awake but potentially shifted to TASK_INTERRUPTIBLE state.231 */232static int hvcs_kicked;233 234/*235 * Use by the kthread construct for task operations like waking the sleeping236 * thread and stopping the kthread.237 */238static struct task_struct *hvcs_task;239 240/*241 * We allocate this for the use of all of the hvcs_structs when they fetch242 * partner info.243 */244static unsigned long *hvcs_pi_buff;245 246/* Only allow one hvcs_struct to use the hvcs_pi_buff at a time. */247static DEFINE_SPINLOCK(hvcs_pi_lock);248 249/* One vty-server per hvcs_struct */250struct hvcs_struct {251 struct tty_port port;252 spinlock_t lock;253 254 /*255 * This index identifies this hvcs device as the complement to a256 * specific tty index.257 */258 unsigned int index;259 260 /*261 * Used to tell the driver kernel_thread what operations need to take262 * place upon this hvcs_struct instance.263 */264 int todo_mask;265 266 /*267 * This buffer is required so that when hvcs_write_room() reports that268 * it can send HVCS_BUFF_LEN characters that it will buffer the full269 * HVCS_BUFF_LEN characters if need be. This is essential for opost270 * writes since they do not do high level buffering and expect to be271 * able to send what the driver commits to sending buffering272 * [e.g. tab to space conversions in n_tty.c opost()].273 */274 char buffer[HVCS_BUFF_LEN];275 int chars_in_buffer;276 277 /*278 * Any variable below is valid before a tty is connected and279 * stays valid after the tty is disconnected. These shouldn't be280 * whacked until the kobject refcount reaches zero though some entries281 * may be changed via sysfs initiatives.282 */283 int connected; /* is the vty-server currently connected to a vty? */284 uint32_t p_unit_address; /* partner unit address */285 uint32_t p_partition_ID; /* partner partition ID */286 char p_location_code[HVCS_CLC_LENGTH + 1]; /* CLC + Null Term */287 struct list_head next; /* list management */288 struct vio_dev *vdev;289 struct completion *destroyed;290};291 292static LIST_HEAD(hvcs_structs);293static DEFINE_SPINLOCK(hvcs_structs_lock);294static DEFINE_MUTEX(hvcs_init_mutex);295 296static int hvcs_get_pi(struct hvcs_struct *hvcsd);297static int hvcs_rescan_devices_list(void);298 299static void hvcs_partner_free(struct hvcs_struct *hvcsd);300 301static int hvcs_initialize(void);302 303#define HVCS_SCHED_READ 0x00000001304#define HVCS_QUICK_READ 0x00000002305#define HVCS_TRY_WRITE 0x00000004306#define HVCS_READ_MASK (HVCS_SCHED_READ | HVCS_QUICK_READ)307 308static inline struct hvcs_struct *from_vio_dev(struct vio_dev *viod)309{310 return dev_get_drvdata(&viod->dev);311}312/* The sysfs interface for the driver and devices */313 314static ssize_t hvcs_partner_vtys_show(struct device *dev, struct device_attribute *attr, char *buf)315{316 struct vio_dev *viod = to_vio_dev(dev);317 struct hvcs_struct *hvcsd = from_vio_dev(viod);318 unsigned long flags;319 int retval;320 321 spin_lock_irqsave(&hvcsd->lock, flags);322 retval = sprintf(buf, "%X\n", hvcsd->p_unit_address);323 spin_unlock_irqrestore(&hvcsd->lock, flags);324 return retval;325}326static DEVICE_ATTR(partner_vtys, S_IRUGO, hvcs_partner_vtys_show, NULL);327 328static ssize_t hvcs_partner_clcs_show(struct device *dev, struct device_attribute *attr, char *buf)329{330 struct vio_dev *viod = to_vio_dev(dev);331 struct hvcs_struct *hvcsd = from_vio_dev(viod);332 unsigned long flags;333 int retval;334 335 spin_lock_irqsave(&hvcsd->lock, flags);336 retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]);337 spin_unlock_irqrestore(&hvcsd->lock, flags);338 return retval;339}340static DEVICE_ATTR(partner_clcs, S_IRUGO, hvcs_partner_clcs_show, NULL);341 342static ssize_t hvcs_current_vty_store(struct device *dev, struct device_attribute *attr, const char * buf,343 size_t count)344{345 /*346 * Don't need this feature at the present time because firmware doesn't347 * yet support multiple partners.348 */349 printk(KERN_INFO "HVCS: Denied current_vty change: -EPERM.\n");350 return -EPERM;351}352 353static ssize_t hvcs_current_vty_show(struct device *dev, struct device_attribute *attr, char *buf)354{355 struct vio_dev *viod = to_vio_dev(dev);356 struct hvcs_struct *hvcsd = from_vio_dev(viod);357 unsigned long flags;358 int retval;359 360 spin_lock_irqsave(&hvcsd->lock, flags);361 retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]);362 spin_unlock_irqrestore(&hvcsd->lock, flags);363 return retval;364}365 366static DEVICE_ATTR(current_vty,367 S_IRUGO | S_IWUSR, hvcs_current_vty_show, hvcs_current_vty_store);368 369static ssize_t hvcs_vterm_state_store(struct device *dev, struct device_attribute *attr, const char *buf,370 size_t count)371{372 struct vio_dev *viod = to_vio_dev(dev);373 struct hvcs_struct *hvcsd = from_vio_dev(viod);374 unsigned long flags;375 376 /* writing a '0' to this sysfs entry will result in the disconnect. */377 if (simple_strtol(buf, NULL, 0) != 0)378 return -EINVAL;379 380 spin_lock_irqsave(&hvcsd->lock, flags);381 382 if (hvcsd->port.count > 0) {383 spin_unlock_irqrestore(&hvcsd->lock, flags);384 printk(KERN_INFO "HVCS: vterm state unchanged. "385 "The hvcs device node is still in use.\n");386 return -EPERM;387 }388 389 if (hvcsd->connected == 0) {390 spin_unlock_irqrestore(&hvcsd->lock, flags);391 printk(KERN_INFO "HVCS: vterm state unchanged. The"392 " vty-server is not connected to a vty.\n");393 return -EPERM;394 }395 396 hvcs_partner_free(hvcsd);397 printk(KERN_INFO "HVCS: Closed vty-server@%X and"398 " partner vty@%X:%d connection.\n",399 hvcsd->vdev->unit_address,400 hvcsd->p_unit_address,401 (uint32_t)hvcsd->p_partition_ID);402 403 spin_unlock_irqrestore(&hvcsd->lock, flags);404 return count;405}406 407static ssize_t hvcs_vterm_state_show(struct device *dev, struct device_attribute *attr, char *buf)408{409 struct vio_dev *viod = to_vio_dev(dev);410 struct hvcs_struct *hvcsd = from_vio_dev(viod);411 unsigned long flags;412 int retval;413 414 spin_lock_irqsave(&hvcsd->lock, flags);415 retval = sprintf(buf, "%d\n", hvcsd->connected);416 spin_unlock_irqrestore(&hvcsd->lock, flags);417 return retval;418}419static DEVICE_ATTR(vterm_state, S_IRUGO | S_IWUSR,420 hvcs_vterm_state_show, hvcs_vterm_state_store);421 422static ssize_t hvcs_index_show(struct device *dev, struct device_attribute *attr, char *buf)423{424 struct vio_dev *viod = to_vio_dev(dev);425 struct hvcs_struct *hvcsd = from_vio_dev(viod);426 unsigned long flags;427 int retval;428 429 spin_lock_irqsave(&hvcsd->lock, flags);430 retval = sprintf(buf, "%d\n", hvcsd->index);431 spin_unlock_irqrestore(&hvcsd->lock, flags);432 return retval;433}434 435static DEVICE_ATTR(index, S_IRUGO, hvcs_index_show, NULL);436 437static struct attribute *hvcs_dev_attrs[] = {438 &dev_attr_partner_vtys.attr,439 &dev_attr_partner_clcs.attr,440 &dev_attr_current_vty.attr,441 &dev_attr_vterm_state.attr,442 &dev_attr_index.attr,443 NULL,444};445 446ATTRIBUTE_GROUPS(hvcs_dev);447 448static ssize_t rescan_show(struct device_driver *ddp, char *buf)449{450 /* A 1 means it is updating, a 0 means it is done updating */451 return snprintf(buf, PAGE_SIZE, "%d\n", hvcs_rescan_status);452}453 454static ssize_t rescan_store(struct device_driver *ddp, const char * buf,455 size_t count)456{457 if ((simple_strtol(buf, NULL, 0) != 1)458 && (hvcs_rescan_status != 0))459 return -EINVAL;460 461 hvcs_rescan_status = 1;462 printk(KERN_INFO "HVCS: rescanning partner info for all"463 " vty-servers.\n");464 hvcs_rescan_devices_list();465 hvcs_rescan_status = 0;466 return count;467}468 469static DRIVER_ATTR_RW(rescan);470 471static struct attribute *hvcs_attrs[] = {472 &driver_attr_rescan.attr,473 NULL,474};475 476ATTRIBUTE_GROUPS(hvcs);477 478static void hvcs_kick(void)479{480 hvcs_kicked = 1;481 wmb();482 wake_up_process(hvcs_task);483}484 485static void hvcs_unthrottle(struct tty_struct *tty)486{487 struct hvcs_struct *hvcsd = tty->driver_data;488 unsigned long flags;489 490 spin_lock_irqsave(&hvcsd->lock, flags);491 hvcsd->todo_mask |= HVCS_SCHED_READ;492 spin_unlock_irqrestore(&hvcsd->lock, flags);493 hvcs_kick();494}495 496static void hvcs_throttle(struct tty_struct *tty)497{498 struct hvcs_struct *hvcsd = tty->driver_data;499 unsigned long flags;500 501 spin_lock_irqsave(&hvcsd->lock, flags);502 vio_disable_interrupts(hvcsd->vdev);503 spin_unlock_irqrestore(&hvcsd->lock, flags);504}505 506/*507 * If the device is being removed we don't have to worry about this interrupt508 * handler taking any further interrupts because they are disabled which means509 * the hvcs_struct will always be valid in this handler.510 */511static irqreturn_t hvcs_handle_interrupt(int irq, void *dev_instance)512{513 struct hvcs_struct *hvcsd = dev_instance;514 515 spin_lock(&hvcsd->lock);516 vio_disable_interrupts(hvcsd->vdev);517 hvcsd->todo_mask |= HVCS_SCHED_READ;518 spin_unlock(&hvcsd->lock);519 hvcs_kick();520 521 return IRQ_HANDLED;522}523 524/* This function must be called with the hvcsd->lock held */525static void hvcs_try_write(struct hvcs_struct *hvcsd)526{527 uint32_t unit_address = hvcsd->vdev->unit_address;528 struct tty_struct *tty = hvcsd->port.tty;529 int sent;530 531 if (hvcsd->todo_mask & HVCS_TRY_WRITE) {532 /* won't send partial writes */533 sent = hvc_put_chars(unit_address,534 &hvcsd->buffer[0],535 hvcsd->chars_in_buffer );536 if (sent > 0) {537 hvcsd->chars_in_buffer = 0;538 /* wmb(); */539 hvcsd->todo_mask &= ~(HVCS_TRY_WRITE);540 /* wmb(); */541 542 /*543 * We are still obligated to deliver the data to the544 * hypervisor even if the tty has been closed because545 * we committed to delivering it. But don't try to wake546 * a non-existent tty.547 */548 if (tty) {549 tty_wakeup(tty);550 }551 }552 }553}554 555static int hvcs_io(struct hvcs_struct *hvcsd)556{557 uint32_t unit_address;558 struct tty_struct *tty;559 char buf[HVCS_BUFF_LEN] __ALIGNED__;560 unsigned long flags;561 int got = 0;562 563 spin_lock_irqsave(&hvcsd->lock, flags);564 565 unit_address = hvcsd->vdev->unit_address;566 tty = hvcsd->port.tty;567 568 hvcs_try_write(hvcsd);569 570 if (!tty || tty_throttled(tty)) {571 hvcsd->todo_mask &= ~(HVCS_READ_MASK);572 goto bail;573 } else if (!(hvcsd->todo_mask & (HVCS_READ_MASK)))574 goto bail;575 576 /* remove the read masks */577 hvcsd->todo_mask &= ~(HVCS_READ_MASK);578 579 if (tty_buffer_request_room(&hvcsd->port, HVCS_BUFF_LEN) >= HVCS_BUFF_LEN) {580 got = hvc_get_chars(unit_address,581 &buf[0],582 HVCS_BUFF_LEN);583 tty_insert_flip_string(&hvcsd->port, buf, got);584 }585 586 /* Give the TTY time to process the data we just sent. */587 if (got)588 hvcsd->todo_mask |= HVCS_QUICK_READ;589 590 spin_unlock_irqrestore(&hvcsd->lock, flags);591 /* This is synch -- FIXME :js: it is not! */592 if (got)593 tty_flip_buffer_push(&hvcsd->port);594 else {595 /* Do this _after_ the flip_buffer_push */596 spin_lock_irqsave(&hvcsd->lock, flags);597 vio_enable_interrupts(hvcsd->vdev);598 spin_unlock_irqrestore(&hvcsd->lock, flags);599 }600 601 return hvcsd->todo_mask;602 603 bail:604 spin_unlock_irqrestore(&hvcsd->lock, flags);605 return hvcsd->todo_mask;606}607 608static int khvcsd(void *unused)609{610 struct hvcs_struct *hvcsd;611 int hvcs_todo_mask;612 613 __set_current_state(TASK_RUNNING);614 615 do {616 hvcs_todo_mask = 0;617 hvcs_kicked = 0;618 wmb();619 620 spin_lock(&hvcs_structs_lock);621 list_for_each_entry(hvcsd, &hvcs_structs, next) {622 hvcs_todo_mask |= hvcs_io(hvcsd);623 }624 spin_unlock(&hvcs_structs_lock);625 626 /*627 * If any of the hvcs adapters want to try a write or quick read628 * don't schedule(), yield a smidgen then execute the hvcs_io629 * thread again for those that want the write.630 */631 if (hvcs_todo_mask & (HVCS_TRY_WRITE | HVCS_QUICK_READ)) {632 yield();633 continue;634 }635 636 set_current_state(TASK_INTERRUPTIBLE);637 if (!hvcs_kicked)638 schedule();639 __set_current_state(TASK_RUNNING);640 } while (!kthread_should_stop());641 642 return 0;643}644 645static const struct vio_device_id hvcs_driver_table[] = {646 {"serial-server", "hvterm2"},647 { "", "" }648};649MODULE_DEVICE_TABLE(vio, hvcs_driver_table);650 651static void hvcs_return_index(int index)652{653 /* Paranoia check */654 if (!hvcs_index_list)655 return;656 if (index < 0 || index >= hvcs_index_count)657 return;658 if (hvcs_index_list[index] == -1)659 return;660 else661 hvcs_index_list[index] = -1;662}663 664static void hvcs_destruct_port(struct tty_port *p)665{666 struct hvcs_struct *hvcsd = container_of(p, struct hvcs_struct, port);667 struct completion *comp;668 unsigned long flags;669 670 spin_lock(&hvcs_structs_lock);671 spin_lock_irqsave(&hvcsd->lock, flags);672 673 comp = hvcsd->destroyed;674 /* the list_del poisons the pointers */675 list_del(&(hvcsd->next));676 677 if (hvcsd->connected == 1) {678 hvcs_partner_free(hvcsd);679 printk(KERN_INFO "HVCS: Closed vty-server@%X and"680 " partner vty@%X:%d connection.\n",681 hvcsd->vdev->unit_address,682 hvcsd->p_unit_address,683 (uint32_t)hvcsd->p_partition_ID);684 }685 printk(KERN_INFO "HVCS: Destroyed hvcs_struct for vty-server@%X.\n",686 hvcsd->vdev->unit_address);687 688 hvcsd->vdev = NULL;689 690 hvcsd->p_unit_address = 0;691 hvcsd->p_partition_ID = 0;692 hvcsd->destroyed = NULL;693 hvcs_return_index(hvcsd->index);694 memset(&hvcsd->p_location_code[0], 0x00, HVCS_CLC_LENGTH + 1);695 696 spin_unlock_irqrestore(&hvcsd->lock, flags);697 spin_unlock(&hvcs_structs_lock);698 699 kfree(hvcsd);700 if (comp)701 complete(comp);702}703 704static const struct tty_port_operations hvcs_port_ops = {705 .destruct = hvcs_destruct_port,706};707 708static int hvcs_get_index(void)709{710 int i;711 /* Paranoia check */712 if (!hvcs_index_list) {713 printk(KERN_ERR "HVCS: hvcs_index_list NOT valid!.\n");714 return -EFAULT;715 }716 /* Find the numerically lowest first free index. */717 for(i = 0; i < hvcs_index_count; i++) {718 if (hvcs_index_list[i] == -1) {719 hvcs_index_list[i] = 0;720 return i;721 }722 }723 return -1;724}725 726static int hvcs_probe(727 struct vio_dev *dev,728 const struct vio_device_id *id)729{730 struct hvcs_struct *hvcsd;731 int index, rc;732 733 if (!dev || !id) {734 printk(KERN_ERR "HVCS: probed with invalid parameter.\n");735 return -EPERM;736 }737 738 /* Make sure we are properly initialized */739 rc = hvcs_initialize();740 if (rc) {741 pr_err("HVCS: Failed to initialize core driver.\n");742 return rc;743 }744 745 /* early to avoid cleanup on failure */746 index = hvcs_get_index();747 if (index < 0) {748 return -EFAULT;749 }750 751 hvcsd = kzalloc(sizeof(*hvcsd), GFP_KERNEL);752 if (!hvcsd)753 return -ENODEV;754 755 tty_port_init(&hvcsd->port);756 hvcsd->port.ops = &hvcs_port_ops;757 spin_lock_init(&hvcsd->lock);758 759 hvcsd->vdev = dev;760 dev_set_drvdata(&dev->dev, hvcsd);761 762 hvcsd->index = index;763 764 /* hvcsd->index = ++hvcs_struct_count; */765 hvcsd->chars_in_buffer = 0;766 hvcsd->todo_mask = 0;767 hvcsd->connected = 0;768 769 /*770 * This will populate the hvcs_struct's partner info fields for the771 * first time.772 */773 if (hvcs_get_pi(hvcsd)) {774 printk(KERN_ERR "HVCS: Failed to fetch partner"775 " info for vty-server@%X on device probe.\n",776 hvcsd->vdev->unit_address);777 }778 779 /*780 * If a user app opens a tty that corresponds to this vty-server before781 * the hvcs_struct has been added to the devices list then the user app782 * will get -ENODEV.783 */784 spin_lock(&hvcs_structs_lock);785 list_add_tail(&(hvcsd->next), &hvcs_structs);786 spin_unlock(&hvcs_structs_lock);787 788 printk(KERN_INFO "HVCS: vty-server@%X added to the vio bus.\n", dev->unit_address);789 790 /*791 * DON'T enable interrupts here because there is no user to receive the792 * data.793 */794 return 0;795}796 797static void hvcs_remove(struct vio_dev *dev)798{799 struct hvcs_struct *hvcsd = dev_get_drvdata(&dev->dev);800 DECLARE_COMPLETION_ONSTACK(comp);801 unsigned long flags;802 struct tty_struct *tty;803 804 /* By this time the vty-server won't be getting any more interrupts */805 806 spin_lock_irqsave(&hvcsd->lock, flags);807 808 hvcsd->destroyed = ∁809 tty = tty_port_tty_get(&hvcsd->port);810 811 spin_unlock_irqrestore(&hvcsd->lock, flags);812 813 /*814 * The tty should always be valid at this time unless a815 * simultaneous tty close already cleaned up the hvcs_struct.816 */817 if (tty) {818 tty_vhangup(tty);819 tty_kref_put(tty);820 }821 822 tty_port_put(&hvcsd->port);823 wait_for_completion(&comp);824 printk(KERN_INFO "HVCS: vty-server@%X removed from the"825 " vio bus.\n", dev->unit_address);826};827 828static struct vio_driver hvcs_vio_driver = {829 .id_table = hvcs_driver_table,830 .probe = hvcs_probe,831 .remove = hvcs_remove,832 .name = hvcs_driver_name,833 .driver = {834 .groups = hvcs_groups,835 .dev_groups = hvcs_dev_groups,836 },837};838 839/* Only called from hvcs_get_pi please */840static void hvcs_set_pi(struct hvcs_partner_info *pi, struct hvcs_struct *hvcsd)841{842 hvcsd->p_unit_address = pi->unit_address;843 hvcsd->p_partition_ID = pi->partition_ID;844 845 /* copy the null-term char too */846 strscpy(hvcsd->p_location_code, pi->location_code,847 sizeof(hvcsd->p_location_code));848}849 850/*851 * Traverse the list and add the partner info that is found to the hvcs_struct852 * struct entry. NOTE: At this time I know that partner info will return a853 * single entry but in the future there may be multiple partner info entries per854 * vty-server and you'll want to zero out that list and reset it. If for some855 * reason you have an old version of this driver but there IS more than one856 * partner info then hvcsd->p_* will hold the last partner info data from the857 * firmware query. A good way to update this code would be to replace the three858 * partner info fields in hvcs_struct with a list of hvcs_partner_info859 * instances.860 *861 * This function must be called with the hvcsd->lock held.862 */863static int hvcs_get_pi(struct hvcs_struct *hvcsd)864{865 struct hvcs_partner_info *pi;866 uint32_t unit_address = hvcsd->vdev->unit_address;867 struct list_head head;868 int retval;869 870 spin_lock(&hvcs_pi_lock);871 if (!hvcs_pi_buff) {872 spin_unlock(&hvcs_pi_lock);873 return -EFAULT;874 }875 retval = hvcs_get_partner_info(unit_address, &head, hvcs_pi_buff);876 spin_unlock(&hvcs_pi_lock);877 if (retval) {878 printk(KERN_ERR "HVCS: Failed to fetch partner"879 " info for vty-server@%x.\n", unit_address);880 return retval;881 }882 883 /* nixes the values if the partner vty went away */884 hvcsd->p_unit_address = 0;885 hvcsd->p_partition_ID = 0;886 887 list_for_each_entry(pi, &head, node)888 hvcs_set_pi(pi, hvcsd);889 890 hvcs_free_partner_info(&head);891 return 0;892}893 894/*895 * This function is executed by the driver "rescan" sysfs entry. It shouldn't896 * be executed elsewhere, in order to prevent deadlock issues.897 */898static int hvcs_rescan_devices_list(void)899{900 struct hvcs_struct *hvcsd;901 unsigned long flags;902 903 spin_lock(&hvcs_structs_lock);904 905 list_for_each_entry(hvcsd, &hvcs_structs, next) {906 spin_lock_irqsave(&hvcsd->lock, flags);907 hvcs_get_pi(hvcsd);908 spin_unlock_irqrestore(&hvcsd->lock, flags);909 }910 911 spin_unlock(&hvcs_structs_lock);912 913 return 0;914}915 916/*917 * Farm this off into its own function because it could be more complex once918 * multiple partners support is added. This function should be called with919 * the hvcsd->lock held.920 */921static int hvcs_has_pi(struct hvcs_struct *hvcsd)922{923 if ((!hvcsd->p_unit_address) || (!hvcsd->p_partition_ID))924 return 0;925 return 1;926}927 928/*929 * NOTE: It is possible that the super admin removed a partner vty and then930 * added a different vty as the new partner.931 *932 * This function must be called with the hvcsd->lock held.933 */934static int hvcs_partner_connect(struct hvcs_struct *hvcsd)935{936 int retval;937 unsigned int unit_address = hvcsd->vdev->unit_address;938 939 /*940 * If there wasn't any pi when the device was added it doesn't meant941 * there isn't any now. This driver isn't notified when a new partner942 * vty is added to a vty-server so we discover changes on our own.943 * Please see comments in hvcs_register_connection() for justification944 * of this bizarre code.945 */946 retval = hvcs_register_connection(unit_address,947 hvcsd->p_partition_ID,948 hvcsd->p_unit_address);949 if (!retval) {950 hvcsd->connected = 1;951 return 0;952 } else if (retval != -EINVAL)953 return retval;954 955 /*956 * As per the spec re-get the pi and try again if -EINVAL after the957 * first connection attempt.958 */959 if (hvcs_get_pi(hvcsd))960 return -ENOMEM;961 962 if (!hvcs_has_pi(hvcsd))963 return -ENODEV;964 965 retval = hvcs_register_connection(unit_address,966 hvcsd->p_partition_ID,967 hvcsd->p_unit_address);968 if (retval != -EINVAL) {969 hvcsd->connected = 1;970 return retval;971 }972 973 /*974 * EBUSY is the most likely scenario though the vty could have been975 * removed or there really could be an hcall error due to the parameter976 * data but thanks to ambiguous firmware return codes we can't really977 * tell.978 */979 printk(KERN_INFO "HVCS: vty-server or partner"980 " vty is busy. Try again later.\n");981 return -EBUSY;982}983 984/* This function must be called with the hvcsd->lock held */985static void hvcs_partner_free(struct hvcs_struct *hvcsd)986{987 int retval;988 do {989 retval = hvcs_free_connection(hvcsd->vdev->unit_address);990 } while (retval == -EBUSY);991 hvcsd->connected = 0;992}993 994/* This helper function must be called WITHOUT the hvcsd->lock held */995static int hvcs_enable_device(struct hvcs_struct *hvcsd, uint32_t unit_address,996 unsigned int irq, struct vio_dev *vdev)997{998 unsigned long flags;999 int rc;1000 1001 /*1002 * It is possible that the vty-server was removed between the time that1003 * the conn was registered and now.1004 */1005 rc = request_irq(irq, &hvcs_handle_interrupt, 0, "ibmhvcs", hvcsd);1006 if (!rc) {1007 /*1008 * It is possible the vty-server was removed after the irq was1009 * requested but before we have time to enable interrupts.1010 */1011 if (vio_enable_interrupts(vdev) == H_SUCCESS)1012 return 0;1013 else {1014 printk(KERN_ERR "HVCS: int enable failed for"1015 " vty-server@%X.\n", unit_address);1016 free_irq(irq, hvcsd);1017 }1018 } else1019 printk(KERN_ERR "HVCS: irq req failed for"1020 " vty-server@%X.\n", unit_address);1021 1022 spin_lock_irqsave(&hvcsd->lock, flags);1023 hvcs_partner_free(hvcsd);1024 spin_unlock_irqrestore(&hvcsd->lock, flags);1025 1026 return rc;1027 1028}1029 1030/*1031 * This always increments the kref ref count if the call is successful.1032 * Please remember to dec when you are done with the instance.1033 *1034 * NOTICE: Do NOT hold either the hvcs_struct.lock or hvcs_structs_lock when1035 * calling this function or you will get deadlock.1036 */1037static struct hvcs_struct *hvcs_get_by_index(int index)1038{1039 struct hvcs_struct *hvcsd;1040 unsigned long flags;1041 1042 spin_lock(&hvcs_structs_lock);1043 list_for_each_entry(hvcsd, &hvcs_structs, next) {1044 spin_lock_irqsave(&hvcsd->lock, flags);1045 if (hvcsd->index == index) {1046 tty_port_get(&hvcsd->port);1047 spin_unlock_irqrestore(&hvcsd->lock, flags);1048 spin_unlock(&hvcs_structs_lock);1049 return hvcsd;1050 }1051 spin_unlock_irqrestore(&hvcsd->lock, flags);1052 }1053 spin_unlock(&hvcs_structs_lock);1054 1055 return NULL;1056}1057 1058static int hvcs_install(struct tty_driver *driver, struct tty_struct *tty)1059{1060 struct hvcs_struct *hvcsd;1061 struct vio_dev *vdev;1062 unsigned long unit_address, flags;1063 unsigned int irq;1064 int retval;1065 1066 /*1067 * Is there a vty-server that shares the same index?1068 * This function increments the kref index.1069 */1070 hvcsd = hvcs_get_by_index(tty->index);1071 if (!hvcsd) {1072 printk(KERN_WARNING "HVCS: open failed, no device associated"1073 " with tty->index %d.\n", tty->index);1074 return -ENODEV;1075 }1076 1077 spin_lock_irqsave(&hvcsd->lock, flags);1078 1079 if (hvcsd->connected == 0) {1080 retval = hvcs_partner_connect(hvcsd);1081 if (retval) {1082 spin_unlock_irqrestore(&hvcsd->lock, flags);1083 printk(KERN_WARNING "HVCS: partner connect failed.\n");1084 goto err_put;1085 }1086 }1087 1088 hvcsd->port.count = 0;1089 hvcsd->port.tty = tty;1090 tty->driver_data = hvcsd;1091 1092 memset(&hvcsd->buffer[0], 0x00, HVCS_BUFF_LEN);1093 1094 /*1095 * Save these in the spinlock for the enable operations that need them1096 * outside of the spinlock.1097 */1098 irq = hvcsd->vdev->irq;1099 vdev = hvcsd->vdev;1100 unit_address = hvcsd->vdev->unit_address;1101 1102 hvcsd->todo_mask |= HVCS_SCHED_READ;1103 spin_unlock_irqrestore(&hvcsd->lock, flags);1104 1105 /*1106 * This must be done outside of the spinlock because it requests irqs1107 * and will grab the spinlock and free the connection if it fails.1108 */1109 retval = hvcs_enable_device(hvcsd, unit_address, irq, vdev);1110 if (retval) {1111 printk(KERN_WARNING "HVCS: enable device failed.\n");1112 goto err_put;1113 }1114 1115 retval = tty_port_install(&hvcsd->port, driver, tty);1116 if (retval)1117 goto err_irq;1118 1119 return 0;1120err_irq:1121 spin_lock_irqsave(&hvcsd->lock, flags);1122 vio_disable_interrupts(hvcsd->vdev);1123 spin_unlock_irqrestore(&hvcsd->lock, flags);1124 free_irq(irq, hvcsd);1125err_put:1126 tty_port_put(&hvcsd->port);1127 1128 return retval;1129}1130 1131/*1132 * This is invoked via the tty_open interface when a user app connects to the1133 * /dev node.1134 */1135static int hvcs_open(struct tty_struct *tty, struct file *filp)1136{1137 struct hvcs_struct *hvcsd = tty->driver_data;1138 unsigned long flags;1139 1140 spin_lock_irqsave(&hvcsd->lock, flags);1141 hvcsd->port.count++;1142 hvcsd->todo_mask |= HVCS_SCHED_READ;1143 spin_unlock_irqrestore(&hvcsd->lock, flags);1144 1145 hvcs_kick();1146 1147 printk(KERN_INFO "HVCS: vty-server@%X connection opened.\n",1148 hvcsd->vdev->unit_address );1149 1150 return 0;1151}1152 1153static void hvcs_close(struct tty_struct *tty, struct file *filp)1154{1155 struct hvcs_struct *hvcsd;1156 unsigned long flags;1157 int irq;1158 1159 /*1160 * Is someone trying to close the file associated with this device after1161 * we have hung up? If so tty->driver_data wouldn't be valid.1162 */1163 if (tty_hung_up_p(filp))1164 return;1165 1166 /*1167 * No driver_data means that this close was probably issued after a1168 * failed hvcs_open by the tty layer's release_dev() api and we can just1169 * exit cleanly.1170 */1171 if (!tty->driver_data)1172 return;1173 1174 hvcsd = tty->driver_data;1175 1176 spin_lock_irqsave(&hvcsd->lock, flags);1177 if (hvcsd->port.count == 0) {1178 spin_unlock_irqrestore(&hvcsd->lock, flags);1179 return;1180 } else if (--hvcsd->port.count == 0) {1181 1182 vio_disable_interrupts(hvcsd->vdev);1183 1184 /*1185 * NULL this early so that the kernel_thread doesn't try to1186 * execute any operations on the TTY even though it is obligated1187 * to deliver any pending I/O to the hypervisor.1188 */1189 hvcsd->port.tty = NULL;1190 1191 irq = hvcsd->vdev->irq;1192 spin_unlock_irqrestore(&hvcsd->lock, flags);1193 1194 tty_wait_until_sent(tty, HVCS_CLOSE_WAIT);1195 1196 free_irq(irq, hvcsd);1197 return;1198 } else if (hvcsd->port.count < 0) {1199 printk(KERN_ERR "HVCS: vty-server@%X open_count: %d is mismanaged.\n",1200 hvcsd->vdev->unit_address, hvcsd->port.count);1201 }1202 1203 spin_unlock_irqrestore(&hvcsd->lock, flags);1204}1205 1206static void hvcs_cleanup(struct tty_struct * tty)1207{1208 struct hvcs_struct *hvcsd = tty->driver_data;1209 1210 /*1211 * This line is important because it tells hvcs_open that this1212 * device needs to be re-configured the next time hvcs_open is1213 * called.1214 */1215 tty->driver_data = NULL;1216 1217 tty_port_put(&hvcsd->port);1218}1219 1220static void hvcs_hangup(struct tty_struct * tty)1221{1222 struct hvcs_struct *hvcsd = tty->driver_data;1223 unsigned long flags;1224 int irq;1225 1226 spin_lock_irqsave(&hvcsd->lock, flags);1227 1228 /*1229 * Don't kref put inside the spinlock because the destruction1230 * callback may use the spinlock and it may get called before the1231 * spinlock has been released.1232 */1233 vio_disable_interrupts(hvcsd->vdev);1234 1235 hvcsd->todo_mask = 0;1236 hvcsd->port.tty = NULL;1237 hvcsd->port.count = 0;1238 1239 /* This will drop any buffered data on the floor which is OK in a hangup1240 * scenario. */1241 memset(&hvcsd->buffer[0], 0x00, HVCS_BUFF_LEN);1242 hvcsd->chars_in_buffer = 0;1243 1244 irq = hvcsd->vdev->irq;1245 1246 spin_unlock_irqrestore(&hvcsd->lock, flags);1247 1248 free_irq(irq, hvcsd);1249}1250 1251/*1252 * NOTE: This is almost always from_user since user level apps interact with the1253 * /dev nodes. I'm trusting that if hvcs_write gets called and interrupted by1254 * hvcs_remove (which removes the target device and executes tty_hangup()) that1255 * tty_hangup will allow hvcs_write time to complete execution before it1256 * terminates our device.1257 */1258static ssize_t hvcs_write(struct tty_struct *tty, const u8 *buf, size_t count)1259{1260 struct hvcs_struct *hvcsd = tty->driver_data;1261 unsigned int unit_address;1262 const unsigned char *charbuf;1263 unsigned long flags;1264 size_t total_sent = 0;1265 size_t tosend = 0;1266 int result = 0;1267 1268 /*1269 * If they don't check the return code off of their open they may1270 * attempt this even if there is no connected device.1271 */1272 if (!hvcsd)1273 return -ENODEV;1274 1275 /* Reasonable size to prevent user level flooding */1276 if (count > HVCS_MAX_FROM_USER) {1277 printk(KERN_WARNING "HVCS write: count being truncated to"1278 " HVCS_MAX_FROM_USER.\n");1279 count = HVCS_MAX_FROM_USER;1280 }1281 1282 charbuf = buf;1283 1284 spin_lock_irqsave(&hvcsd->lock, flags);1285 1286 /*1287 * Somehow an open succeeded but the device was removed or the1288 * connection terminated between the vty-server and partner vty during1289 * the middle of a write operation? This is a crummy place to do this1290 * but we want to keep it all in the spinlock.1291 */1292 if (hvcsd->port.count <= 0) {1293 spin_unlock_irqrestore(&hvcsd->lock, flags);1294 return -ENODEV;1295 }1296 1297 unit_address = hvcsd->vdev->unit_address;1298 1299 while (count > 0) {1300 tosend = min_t(size_t, count,1301 (HVCS_BUFF_LEN - hvcsd->chars_in_buffer));1302 /*1303 * No more space, this probably means that the last call to1304 * hvcs_write() didn't succeed and the buffer was filled up.1305 */1306 if (!tosend)1307 break;1308 1309 memcpy(&hvcsd->buffer[hvcsd->chars_in_buffer],1310 &charbuf[total_sent],1311 tosend);1312 1313 hvcsd->chars_in_buffer += tosend;1314 1315 result = 0;1316 1317 /*1318 * If this is true then we don't want to try writing to the1319 * hypervisor because that is the kernel_threads job now. We'll1320 * just add to the buffer.1321 */1322 if (!(hvcsd->todo_mask & HVCS_TRY_WRITE))1323 /* won't send partial writes */1324 result = hvc_put_chars(unit_address,1325 &hvcsd->buffer[0],1326 hvcsd->chars_in_buffer);1327 1328 /*1329 * Since we know we have enough room in hvcsd->buffer for1330 * tosend we record that it was sent regardless of whether the1331 * hypervisor actually took it because we have it buffered.1332 */1333 total_sent+=tosend;1334 count-=tosend;1335 if (result == 0) {1336 hvcsd->todo_mask |= HVCS_TRY_WRITE;1337 hvcs_kick();1338 break;1339 }1340 1341 hvcsd->chars_in_buffer = 0;1342 /*1343 * Test after the chars_in_buffer reset otherwise this could1344 * deadlock our writes if hvc_put_chars fails.1345 */1346 if (result < 0)1347 break;1348 }1349 1350 spin_unlock_irqrestore(&hvcsd->lock, flags);1351 1352 if (result == -1)1353 return -EIO;1354 else1355 return total_sent;1356}1357 1358/*1359 * This is really asking how much can we guarantee that we can send or that we1360 * absolutely WILL BUFFER if we can't send it. This driver MUST honor the1361 * return value, hence the reason for hvcs_struct buffering.1362 */1363static unsigned int hvcs_write_room(struct tty_struct *tty)1364{1365 struct hvcs_struct *hvcsd = tty->driver_data;1366 1367 if (!hvcsd || hvcsd->port.count <= 0)1368 return 0;1369 1370 return HVCS_BUFF_LEN - hvcsd->chars_in_buffer;1371}1372 1373static unsigned int hvcs_chars_in_buffer(struct tty_struct *tty)1374{1375 struct hvcs_struct *hvcsd = tty->driver_data;1376 1377 return hvcsd->chars_in_buffer;1378}1379 1380static const struct tty_operations hvcs_ops = {1381 .install = hvcs_install,1382 .open = hvcs_open,1383 .close = hvcs_close,1384 .cleanup = hvcs_cleanup,1385 .hangup = hvcs_hangup,1386 .write = hvcs_write,1387 .write_room = hvcs_write_room,1388 .chars_in_buffer = hvcs_chars_in_buffer,1389 .unthrottle = hvcs_unthrottle,1390 .throttle = hvcs_throttle,1391};1392 1393static int hvcs_alloc_index_list(int n)1394{1395 int i;1396 1397 hvcs_index_list = kmalloc_array(n, sizeof(hvcs_index_count),1398 GFP_KERNEL);1399 if (!hvcs_index_list)1400 return -ENOMEM;1401 hvcs_index_count = n;1402 for (i = 0; i < hvcs_index_count; i++)1403 hvcs_index_list[i] = -1;1404 return 0;1405}1406 1407static void hvcs_free_index_list(void)1408{1409 /* Paranoia check to be thorough. */1410 kfree(hvcs_index_list);1411 hvcs_index_list = NULL;1412 hvcs_index_count = 0;1413}1414 1415static int hvcs_initialize(void)1416{1417 int rc, num_ttys_to_alloc;1418 1419 mutex_lock(&hvcs_init_mutex);1420 if (hvcs_task) {1421 mutex_unlock(&hvcs_init_mutex);1422 return 0;1423 }1424 1425 /* Has the user specified an overload with an insmod param? */1426 if (hvcs_parm_num_devs <= 0 ||1427 (hvcs_parm_num_devs > HVCS_MAX_SERVER_ADAPTERS)) {1428 num_ttys_to_alloc = HVCS_DEFAULT_SERVER_ADAPTERS;1429 } else1430 num_ttys_to_alloc = hvcs_parm_num_devs;1431 1432 hvcs_tty_driver = tty_alloc_driver(num_ttys_to_alloc,1433 TTY_DRIVER_REAL_RAW);1434 if (IS_ERR(hvcs_tty_driver)) {1435 mutex_unlock(&hvcs_init_mutex);1436 return PTR_ERR(hvcs_tty_driver);1437 }1438 1439 if (hvcs_alloc_index_list(num_ttys_to_alloc)) {1440 rc = -ENOMEM;1441 goto index_fail;1442 }1443 1444 hvcs_tty_driver->driver_name = hvcs_driver_name;1445 hvcs_tty_driver->name = hvcs_device_node;1446 1447 /*1448 * We'll let the system assign us a major number, indicated by leaving1449 * it blank.1450 */1451 1452 hvcs_tty_driver->minor_start = HVCS_MINOR_START;1453 hvcs_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM;1454 1455 /*1456 * We role our own so that we DONT ECHO. We can't echo because the1457 * device we are connecting to already echoes by default and this would1458 * throw us into a horrible recursive echo-echo-echo loop.1459 */1460 hvcs_tty_driver->init_termios = hvcs_tty_termios;1461 1462 tty_set_operations(hvcs_tty_driver, &hvcs_ops);1463 1464 /*1465 * The following call will result in sysfs entries that denote the1466 * dynamically assigned major and minor numbers for our devices.1467 */1468 if (tty_register_driver(hvcs_tty_driver)) {1469 printk(KERN_ERR "HVCS: registration as a tty driver failed.\n");1470 rc = -EIO;1471 goto register_fail;1472 }1473 1474 hvcs_pi_buff = (unsigned long *) __get_free_page(GFP_KERNEL);1475 if (!hvcs_pi_buff) {1476 rc = -ENOMEM;1477 goto buff_alloc_fail;1478 }1479 1480 hvcs_task = kthread_run(khvcsd, NULL, "khvcsd");1481 if (IS_ERR(hvcs_task)) {1482 printk(KERN_ERR "HVCS: khvcsd creation failed.\n");1483 rc = -EIO;1484 goto kthread_fail;1485 }1486 mutex_unlock(&hvcs_init_mutex);1487 return 0;1488 1489kthread_fail:1490 free_page((unsigned long)hvcs_pi_buff);1491buff_alloc_fail:1492 tty_unregister_driver(hvcs_tty_driver);1493register_fail:1494 hvcs_free_index_list();1495index_fail:1496 tty_driver_kref_put(hvcs_tty_driver);1497 hvcs_tty_driver = NULL;1498 mutex_unlock(&hvcs_init_mutex);1499 return rc;1500}1501 1502static int __init hvcs_module_init(void)1503{1504 int rc = vio_register_driver(&hvcs_vio_driver);1505 if (rc) {1506 printk(KERN_ERR "HVCS: can't register vio driver\n");1507 return rc;1508 }1509 1510 pr_info("HVCS: Driver registered.\n");1511 1512 return 0;1513}1514 1515static void __exit hvcs_module_exit(void)1516{1517 /*1518 * This driver receives hvcs_remove callbacks for each device upon1519 * module removal.1520 */1521 vio_unregister_driver(&hvcs_vio_driver);1522 if (!hvcs_task)1523 return;1524 1525 /*1526 * This synchronous operation will wake the khvcsd kthread if it is1527 * asleep and will return when khvcsd has terminated.1528 */1529 kthread_stop(hvcs_task);1530 1531 spin_lock(&hvcs_pi_lock);1532 free_page((unsigned long)hvcs_pi_buff);1533 hvcs_pi_buff = NULL;1534 spin_unlock(&hvcs_pi_lock);1535 1536 tty_unregister_driver(hvcs_tty_driver);1537 1538 hvcs_free_index_list();1539 1540 tty_driver_kref_put(hvcs_tty_driver);1541 1542 printk(KERN_INFO "HVCS: driver module removed.\n");1543}1544 1545module_init(hvcs_module_init);1546module_exit(hvcs_module_exit);1547