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hvcs.c
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/*
* IBM eServer Hypervisor Virtual Console Server Device Driver
* Copyright (C) 2003, 2004 IBM Corp.
* Ryan S. Arnold (rsa@us.ibm.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Author(s) : Ryan S. Arnold <rsa@us.ibm.com>
*
* This is the device driver for the IBM Hypervisor Virtual Console Server,
* "hvcs". The IBM hvcs provides a tty driver interface to allow Linux
* user space applications access to the system consoles of logically
* partitioned operating systems, e.g. Linux, running on the same partitioned
* Power5 ppc64 system. Physical hardware consoles per partition are not
* practical on this hardware so system consoles are accessed by this driver
* using inter-partition firmware interfaces to virtual terminal devices.
*
* A vty is known to the HMC as a "virtual serial server adapter". It is a
* virtual terminal device that is created by firmware upon partition creation
* to act as a partitioned OS's console device.
*
* Firmware dynamically (via hotplug) exposes vty-servers to a running ppc64
* Linux system upon their creation by the HMC or their exposure during boot.
* The non-user interactive backend of this driver is implemented as a vio
* device driver so that it can receive notification of vty-server lifetimes
* after it registers with the vio bus to handle vty-server probe and remove
* callbacks.
*
* Many vty-servers can be configured to connect to one vty, but a vty can
* only be actively connected to by a single vty-server, in any manner, at one
* time. If the HMC is currently hosting the console for a target Linux
* partition; attempts to open the tty device to the partition's console using
* the hvcs on any partition will return -EBUSY with every open attempt until
* the HMC frees the connection between its vty-server and the desired
* partition's vty device. Conversely, a vty-server may only be connected to
* a single vty at one time even though it may have several configured vty
* partner possibilities.
*
* Firmware does not provide notification of vty partner changes to this
* driver. This means that an HMC Super Admin may add or remove partner vtys
* from a vty-server's partner list but the changes will not be signaled to
* the vty-server. Firmware only notifies the driver when a vty-server is
* added or removed from the system. To compensate for this deficiency, this
* driver implements a sysfs update attribute which provides a method for
* rescanning partner information upon a user's request.
*
* Each vty-server, prior to being exposed to this driver is reference counted
* using the 2.6 Linux kernel kobject construct. This kobject is also used by
* the vio bus to provide a vio device sysfs entry that this driver attaches
* device specific attributes to, including partner information. The vio bus
* framework also provides a sysfs entry for each vio driver. The hvcs driver
* provides driver attributes in this entry.
*
* For direction on installation and usage of this driver please reference
* Documentation/powerpc/hvcs.txt.
*/
#include <linux/device.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/kobject.h>
#include <linux/kthread.h>
#include <linux/list.h>
#include <linux/major.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/stat.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <asm/hvconsole.h>
#include <asm/hvcserver.h>
#include <asm/uaccess.h>
#include <asm/vio.h>
/*
* 1.3.0 -> 1.3.1 In hvcs_open memset(..,0x00,..) instead of memset(..,0x3F,00).
* Removed braces around single statements following conditionals. Removed '=
* 0' after static int declarations since these default to zero. Removed
* list_for_each_safe() and replaced with list_for_each_entry() in
* hvcs_get_by_index(). The 'safe' version is un-needed now that the driver is
* using spinlocks. Changed spin_lock_irqsave() to spin_lock() when locking
* hvcs_structs_lock and hvcs_pi_lock since these are not touched in an int
* handler. Initialized hvcs_structs_lock and hvcs_pi_lock to
* SPIN_LOCK_UNLOCKED at declaration time rather than in hvcs_module_init().
* Added spin_lock around list_del() in destroy_hvcs_struct() to protect the
* list traversals from a deletion. Removed '= NULL' from pointer declaration
* statements since they are initialized NULL by default. Removed wmb()
* instances from hvcs_try_write(). They probably aren't needed with locking in
* place. Added check and cleanup for hvcs_pi_buff = kmalloc() in
* hvcs_module_init(). Exposed hvcs_struct.index via a sysfs attribute so that
* the coupling between /dev/hvcs* and a vty-server can be automatically
* determined. Moved kobject_put() in hvcs_open outside of the
* spin_unlock_irqrestore().
*
* 1.3.1 -> 1.3.2 Changed method for determining hvcs_struct->index and had it
* align with how the tty layer always assigns the lowest index available. This
* change resulted in a list of ints that denotes which indexes are available.
* Device additions and removals use the new hvcs_get_index() and
* hvcs_return_index() helper functions. The list is created with
* hvsc_alloc_index_list() and it is destroyed with hvcs_free_index_list().
* Without these fixes hotplug vty-server adapter support goes crazy with this
* driver if the user removes a vty-server adapter. Moved free_irq() outside of
* the hvcs_final_close() function in order to get it out of the spinlock.
* Rearranged hvcs_close(). Cleaned up some printks and did some housekeeping
* on the changelog. Removed local CLC_LENGTH and used HVCS_CLC_LENGTH from
* arch/ppc64/hvcserver.h.
*
* 1.3.2 -> 1.3.3 Replaced yield() in hvcs_close() with tty_wait_until_sent() to
* prevent possible lockup with realtime scheduling as similarily pointed out by
* akpm in hvc_console. Changed resulted in the removal of hvcs_final_close()
* to reorder cleanup operations and prevent discarding of pending data during
* an hvcs_close(). Removed spinlock protection of hvcs_struct data members in
* hvcs_write_room() and hvcs_chars_in_buffer() because they aren't needed.
*/
#define HVCS_DRIVER_VERSION "1.3.3"
MODULE_AUTHOR("Ryan S. Arnold <rsa@us.ibm.com>");
MODULE_DESCRIPTION("IBM hvcs (Hypervisor Virtual Console Server) Driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(HVCS_DRIVER_VERSION);
/*
* Wait this long per iteration while trying to push buffered data to the
* hypervisor before allowing the tty to complete a close operation.
*/
#define HVCS_CLOSE_WAIT (HZ/100) /* 1/10 of a second */
/*
* Since the Linux TTY code does not currently (2-04-2004) support dynamic
* addition of tty derived devices and we shouldn't allocate thousands of
* tty_device pointers when the number of vty-server & vty partner connections
* will most often be much lower than this, we'll arbitrarily allocate
* HVCS_DEFAULT_SERVER_ADAPTERS tty_structs and cdev's by default when we
* register the tty_driver. This can be overridden using an insmod parameter.
*/
#define HVCS_DEFAULT_SERVER_ADAPTERS 64
/*
* The user can't insmod with more than HVCS_MAX_SERVER_ADAPTERS hvcs device
* nodes as a sanity check. Theoretically there can be over 1 Billion
* vty-server & vty partner connections.
*/
#define HVCS_MAX_SERVER_ADAPTERS 1024
/*
* We let Linux assign us a major number and we start the minors at zero. There
* is no intuitive mapping between minor number and the target vty-server
* adapter except that each new vty-server adapter is always assigned to the
* smallest minor number available.
*/
#define HVCS_MINOR_START 0
/*
* The hcall interface involves putting 8 chars into each of two registers.
* We load up those 2 registers (in arch/ppc64/hvconsole.c) by casting char[16]
* to long[2]. It would work without __ALIGNED__, but a little (tiny) bit
* slower because an unaligned load is slower than aligned load.
*/
#define __ALIGNED__ __attribute__((__aligned__(8)))
/*
* How much data can firmware send with each hvc_put_chars()? Maybe this
* should be moved into an architecture specific area.
*/
#define HVCS_BUFF_LEN 16
/*
* This is the maximum amount of data we'll let the user send us (hvcs_write) at
* once in a chunk as a sanity check.
*/
#define HVCS_MAX_FROM_USER 4096
/*
* Be careful when adding flags to this line discipline. Don't add anything
* that will cause echoing or we'll go into recursive loop echoing chars back
* and forth with the console drivers.
*/
static struct termios hvcs_tty_termios = {
.c_iflag = IGNBRK | IGNPAR,
.c_oflag = OPOST,
.c_cflag = B38400 | CS8 | CREAD | HUPCL,
.c_cc = INIT_C_CC
};
/*
* This value is used to take the place of a command line parameter when the
* module is inserted. It starts as -1 and stays as such if the user doesn't
* specify a module insmod parameter. If they DO specify one then it is set to
* the value of the integer passed in.
*/
static int hvcs_parm_num_devs = -1;
module_param(hvcs_parm_num_devs, int, 0);
char hvcs_driver_name[] = "hvcs";
char hvcs_device_node[] = "hvcs";
char hvcs_driver_string[]
= "IBM hvcs (Hypervisor Virtual Console Server) Driver";
/* Status of partner info rescan triggered via sysfs. */
static int hvcs_rescan_status;
static struct tty_driver *hvcs_tty_driver;
/*
* In order to be somewhat sane this driver always associates the hvcs_struct
* index element with the numerically equal tty->index. This means that a
* hotplugged vty-server adapter will always map to the lowest index valued
* device node. If vty-servers were hotplug removed from the system and then
* new ones added the new vty-server may have the largest slot number of all
* the vty-server adapters in the partition but it may have the lowest dev node
* index of all the adapters due to the hole left by the hotplug removed
* adapter. There are a set of functions provided to get the lowest index for
* a new device as well as return the index to the list. This list is allocated
* with a number of elements equal to the number of device nodes requested when
* the module was inserted.
*/
static int *hvcs_index_list;
/*
* How large is the list? This is kept for traversal since the list is
* dynamically created.
*/
static int hvcs_index_count;
/*
* Used by the khvcsd to pick up I/O operations when the kernel_thread is
* already awake but potentially shifted to TASK_INTERRUPTIBLE state.
*/
static int hvcs_kicked;
/*
* Use by the kthread construct for task operations like waking the sleeping
* thread and stopping the kthread.
*/
static struct task_struct *hvcs_task;
/*
* We allocate this for the use of all of the hvcs_structs when they fetch
* partner info.
*/
static unsigned long *hvcs_pi_buff;
/* Only allow one hvcs_struct to use the hvcs_pi_buff at a time. */
static DEFINE_SPINLOCK(hvcs_pi_lock);
/* One vty-server per hvcs_struct */
struct hvcs_struct {
spinlock_t lock;
/*
* This index identifies this hvcs device as the complement to a
* specific tty index.
*/
unsigned int index;
struct tty_struct *tty;
unsigned int open_count;
/*
* Used to tell the driver kernel_thread what operations need to take
* place upon this hvcs_struct instance.
*/
int todo_mask;
/*
* This buffer is required so that when hvcs_write_room() reports that
* it can send HVCS_BUFF_LEN characters that it will buffer the full
* HVCS_BUFF_LEN characters if need be. This is essential for opost
* writes since they do not do high level buffering and expect to be
* able to send what the driver commits to sending buffering
* [e.g. tab to space conversions in n_tty.c opost()].
*/
char buffer[HVCS_BUFF_LEN];
int chars_in_buffer;
/*
* Any variable below the kobject is valid before a tty is connected and
* stays valid after the tty is disconnected. These shouldn't be
* whacked until the koject refcount reaches zero though some entries
* may be changed via sysfs initiatives.
*/
struct kobject kobj; /* ref count & hvcs_struct lifetime */
int connected; /* is the vty-server currently connected to a vty? */
uint32_t p_unit_address; /* partner unit address */
uint32_t p_partition_ID; /* partner partition ID */
char p_location_code[HVCS_CLC_LENGTH + 1]; /* CLC + Null Term */
struct list_head next; /* list management */
struct vio_dev *vdev;
};
/* Required to back map a kobject to its containing object */
#define from_kobj(kobj) container_of(kobj, struct hvcs_struct, kobj)
static struct list_head hvcs_structs = LIST_HEAD_INIT(hvcs_structs);
static DEFINE_SPINLOCK(hvcs_structs_lock);
static void hvcs_unthrottle(struct tty_struct *tty);
static void hvcs_throttle(struct tty_struct *tty);
static irqreturn_t hvcs_handle_interrupt(int irq, void *dev_instance,
struct pt_regs *regs);
static int hvcs_write(struct tty_struct *tty,
const unsigned char *buf, int count);
static int hvcs_write_room(struct tty_struct *tty);
static int hvcs_chars_in_buffer(struct tty_struct *tty);
static int hvcs_has_pi(struct hvcs_struct *hvcsd);
static void hvcs_set_pi(struct hvcs_partner_info *pi,
struct hvcs_struct *hvcsd);
static int hvcs_get_pi(struct hvcs_struct *hvcsd);
static int hvcs_rescan_devices_list(void);
static int hvcs_partner_connect(struct hvcs_struct *hvcsd);
static void hvcs_partner_free(struct hvcs_struct *hvcsd);
static int hvcs_enable_device(struct hvcs_struct *hvcsd,
uint32_t unit_address, unsigned int irq, struct vio_dev *dev);
static void destroy_hvcs_struct(struct kobject *kobj);
static int hvcs_open(struct tty_struct *tty, struct file *filp);
static void hvcs_close(struct tty_struct *tty, struct file *filp);
static void hvcs_hangup(struct tty_struct * tty);
static void hvcs_create_device_attrs(struct hvcs_struct *hvcsd);
static void hvcs_remove_device_attrs(struct vio_dev *vdev);
static void hvcs_create_driver_attrs(void);
static void hvcs_remove_driver_attrs(void);
static int __devinit hvcs_probe(struct vio_dev *dev,
const struct vio_device_id *id);
static int __devexit hvcs_remove(struct vio_dev *dev);
static int __init hvcs_module_init(void);
static void __exit hvcs_module_exit(void);
#define HVCS_SCHED_READ 0x00000001
#define HVCS_QUICK_READ 0x00000002
#define HVCS_TRY_WRITE 0x00000004
#define HVCS_READ_MASK (HVCS_SCHED_READ | HVCS_QUICK_READ)
static void hvcs_kick(void)
{
hvcs_kicked = 1;
wmb();
wake_up_process(hvcs_task);
}
static void hvcs_unthrottle(struct tty_struct *tty)
{
struct hvcs_struct *hvcsd = tty->driver_data;
unsigned long flags;
spin_lock_irqsave(&hvcsd->lock, flags);
hvcsd->todo_mask |= HVCS_SCHED_READ;
spin_unlock_irqrestore(&hvcsd->lock, flags);
hvcs_kick();
}
static void hvcs_throttle(struct tty_struct *tty)
{
struct hvcs_struct *hvcsd = tty->driver_data;
unsigned long flags;
spin_lock_irqsave(&hvcsd->lock, flags);
vio_disable_interrupts(hvcsd->vdev);
spin_unlock_irqrestore(&hvcsd->lock, flags);
}
/*
* If the device is being removed we don't have to worry about this interrupt
* handler taking any further interrupts because they are disabled which means
* the hvcs_struct will always be valid in this handler.
*/
static irqreturn_t hvcs_handle_interrupt(int irq, void *dev_instance,
struct pt_regs *regs)
{
struct hvcs_struct *hvcsd = dev_instance;
spin_lock(&hvcsd->lock);
vio_disable_interrupts(hvcsd->vdev);
hvcsd->todo_mask |= HVCS_SCHED_READ;
spin_unlock(&hvcsd->lock);
hvcs_kick();
return IRQ_HANDLED;
}
/* This function must be called with the hvcsd->lock held */
static void hvcs_try_write(struct hvcs_struct *hvcsd)
{
uint32_t unit_address = hvcsd->vdev->unit_address;
struct tty_struct *tty = hvcsd->tty;
int sent;
if (hvcsd->todo_mask & HVCS_TRY_WRITE) {
/* won't send partial writes */
sent = hvc_put_chars(unit_address,
&hvcsd->buffer[0],
hvcsd->chars_in_buffer );
if (sent > 0) {
hvcsd->chars_in_buffer = 0;
/* wmb(); */
hvcsd->todo_mask &= ~(HVCS_TRY_WRITE);
/* wmb(); */
/*
* We are still obligated to deliver the data to the
* hypervisor even if the tty has been closed because
* we commited to delivering it. But don't try to wake
* a non-existent tty.
*/
if (tty) {
tty_wakeup(tty);
}
}
}
}
static int hvcs_io(struct hvcs_struct *hvcsd)
{
uint32_t unit_address;
struct tty_struct *tty;
char buf[HVCS_BUFF_LEN] __ALIGNED__;
unsigned long flags;
int got = 0;
int i;
spin_lock_irqsave(&hvcsd->lock, flags);
unit_address = hvcsd->vdev->unit_address;
tty = hvcsd->tty;
hvcs_try_write(hvcsd);
if (!tty || test_bit(TTY_THROTTLED, &tty->flags)) {
hvcsd->todo_mask &= ~(HVCS_READ_MASK);
goto bail;
} else if (!(hvcsd->todo_mask & (HVCS_READ_MASK)))
goto bail;
/* remove the read masks */
hvcsd->todo_mask &= ~(HVCS_READ_MASK);
if ((tty->flip.count + HVCS_BUFF_LEN) < TTY_FLIPBUF_SIZE) {
got = hvc_get_chars(unit_address,
&buf[0],
HVCS_BUFF_LEN);
for (i=0;got && i<got;i++)
tty_insert_flip_char(tty, buf[i], TTY_NORMAL);
}
/* Give the TTY time to process the data we just sent. */
if (got)
hvcsd->todo_mask |= HVCS_QUICK_READ;
spin_unlock_irqrestore(&hvcsd->lock, flags);
if (tty->flip.count) {
/* This is synch because tty->low_latency == 1 */
tty_flip_buffer_push(tty);
}
if (!got) {
/* Do this _after_ the flip_buffer_push */
spin_lock_irqsave(&hvcsd->lock, flags);
vio_enable_interrupts(hvcsd->vdev);
spin_unlock_irqrestore(&hvcsd->lock, flags);
}
return hvcsd->todo_mask;
bail:
spin_unlock_irqrestore(&hvcsd->lock, flags);
return hvcsd->todo_mask;
}
static int khvcsd(void *unused)
{
struct hvcs_struct *hvcsd;
int hvcs_todo_mask;
__set_current_state(TASK_RUNNING);
do {
hvcs_todo_mask = 0;
hvcs_kicked = 0;
wmb();
spin_lock(&hvcs_structs_lock);
list_for_each_entry(hvcsd, &hvcs_structs, next) {
hvcs_todo_mask |= hvcs_io(hvcsd);
}
spin_unlock(&hvcs_structs_lock);
/*
* If any of the hvcs adapters want to try a write or quick read
* don't schedule(), yield a smidgen then execute the hvcs_io
* thread again for those that want the write.
*/
if (hvcs_todo_mask & (HVCS_TRY_WRITE | HVCS_QUICK_READ)) {
yield();
continue;
}
set_current_state(TASK_INTERRUPTIBLE);
if (!hvcs_kicked)
schedule();
__set_current_state(TASK_RUNNING);
} while (!kthread_should_stop());
return 0;
}
static struct vio_device_id hvcs_driver_table[] __devinitdata= {
{"serial-server", "hvterm2"},
{ NULL, }
};
MODULE_DEVICE_TABLE(vio, hvcs_driver_table);
static void hvcs_return_index(int index)
{
/* Paranoia check */
if (!hvcs_index_list)
return;
if (index < 0 || index >= hvcs_index_count)
return;
if (hvcs_index_list[index] == -1)
return;
else
hvcs_index_list[index] = -1;
}
/* callback when the kboject ref count reaches zero */
static void destroy_hvcs_struct(struct kobject *kobj)
{
struct hvcs_struct *hvcsd = from_kobj(kobj);
struct vio_dev *vdev;
unsigned long flags;
spin_lock(&hvcs_structs_lock);
spin_lock_irqsave(&hvcsd->lock, flags);
/* the list_del poisons the pointers */
list_del(&(hvcsd->next));
if (hvcsd->connected == 1) {
hvcs_partner_free(hvcsd);
printk(KERN_INFO "HVCS: Closed vty-server@%X and"
" partner vty@%X:%d connection.\n",
hvcsd->vdev->unit_address,
hvcsd->p_unit_address,
(uint32_t)hvcsd->p_partition_ID);
}
printk(KERN_INFO "HVCS: Destroyed hvcs_struct for vty-server@%X.\n",
hvcsd->vdev->unit_address);
vdev = hvcsd->vdev;
hvcsd->vdev = NULL;
hvcsd->p_unit_address = 0;
hvcsd->p_partition_ID = 0;
hvcs_return_index(hvcsd->index);
memset(&hvcsd->p_location_code[0], 0x00, HVCS_CLC_LENGTH + 1);
spin_unlock_irqrestore(&hvcsd->lock, flags);
spin_unlock(&hvcs_structs_lock);
hvcs_remove_device_attrs(vdev);
kfree(hvcsd);
}
static struct kobj_type hvcs_kobj_type = {
.release = destroy_hvcs_struct,
};
static int hvcs_get_index(void)
{
int i;
/* Paranoia check */
if (!hvcs_index_list) {
printk(KERN_ERR "HVCS: hvcs_index_list NOT valid!.\n");
return -EFAULT;
}
/* Find the numerically lowest first free index. */
for(i = 0; i < hvcs_index_count; i++) {
if (hvcs_index_list[i] == -1) {
hvcs_index_list[i] = 0;
return i;
}
}
return -1;
}
static int __devinit hvcs_probe(
struct vio_dev *dev,
const struct vio_device_id *id)
{
struct hvcs_struct *hvcsd;
int index;
if (!dev || !id) {
printk(KERN_ERR "HVCS: probed with invalid parameter.\n");
return -EPERM;
}
/* early to avoid cleanup on failure */
index = hvcs_get_index();
if (index < 0) {
return -EFAULT;
}
hvcsd = kmalloc(sizeof(*hvcsd), GFP_KERNEL);
if (!hvcsd)
return -ENODEV;
/* hvcsd->tty is zeroed out with the memset */
memset(hvcsd, 0x00, sizeof(*hvcsd));
spin_lock_init(&hvcsd->lock);
/* Automatically incs the refcount the first time */
kobject_init(&hvcsd->kobj);
/* Set up the callback for terminating the hvcs_struct's life */
hvcsd->kobj.ktype = &hvcs_kobj_type;
hvcsd->vdev = dev;
dev->dev.driver_data = hvcsd;
hvcsd->index = index;
/* hvcsd->index = ++hvcs_struct_count; */
hvcsd->chars_in_buffer = 0;
hvcsd->todo_mask = 0;
hvcsd->connected = 0;
/*
* This will populate the hvcs_struct's partner info fields for the
* first time.
*/
if (hvcs_get_pi(hvcsd)) {
printk(KERN_ERR "HVCS: Failed to fetch partner"
" info for vty-server@%X on device probe.\n",
hvcsd->vdev->unit_address);
}
/*
* If a user app opens a tty that corresponds to this vty-server before
* the hvcs_struct has been added to the devices list then the user app
* will get -ENODEV.
*/
spin_lock(&hvcs_structs_lock);
list_add_tail(&(hvcsd->next), &hvcs_structs);
spin_unlock(&hvcs_structs_lock);
hvcs_create_device_attrs(hvcsd);
printk(KERN_INFO "HVCS: vty-server@%X added to the vio bus.\n", dev->unit_address);
/*
* DON'T enable interrupts here because there is no user to receive the
* data.
*/
return 0;
}
static int __devexit hvcs_remove(struct vio_dev *dev)
{
struct hvcs_struct *hvcsd = dev->dev.driver_data;
unsigned long flags;
struct kobject *kobjp;
struct tty_struct *tty;
if (!hvcsd)
return -ENODEV;
/* By this time the vty-server won't be getting any more interrups */
spin_lock_irqsave(&hvcsd->lock, flags);
tty = hvcsd->tty;
kobjp = &hvcsd->kobj;
spin_unlock_irqrestore(&hvcsd->lock, flags);
/*
* Let the last holder of this object cause it to be removed, which
* would probably be tty_hangup below.
*/
kobject_put (kobjp);
/*
* The hangup is a scheduled function which will auto chain call
* hvcs_hangup. The tty should always be valid at this time unless a
* simultaneous tty close already cleaned up the hvcs_struct.
*/
if (tty)
tty_hangup(tty);
printk(KERN_INFO "HVCS: vty-server@%X removed from the"
" vio bus.\n", dev->unit_address);
return 0;
};
static struct vio_driver hvcs_vio_driver = {
.name = hvcs_driver_name,
.id_table = hvcs_driver_table,
.probe = hvcs_probe,
.remove = hvcs_remove,
};
/* Only called from hvcs_get_pi please */
static void hvcs_set_pi(struct hvcs_partner_info *pi, struct hvcs_struct *hvcsd)
{
int clclength;
hvcsd->p_unit_address = pi->unit_address;
hvcsd->p_partition_ID = pi->partition_ID;
clclength = strlen(&pi->location_code[0]);
if (clclength > HVCS_CLC_LENGTH)
clclength = HVCS_CLC_LENGTH;
/* copy the null-term char too */
strncpy(&hvcsd->p_location_code[0],
&pi->location_code[0], clclength + 1);
}
/*
* Traverse the list and add the partner info that is found to the hvcs_struct
* struct entry. NOTE: At this time I know that partner info will return a
* single entry but in the future there may be multiple partner info entries per
* vty-server and you'll want to zero out that list and reset it. If for some
* reason you have an old version of this driver but there IS more than one
* partner info then hvcsd->p_* will hold the last partner info data from the
* firmware query. A good way to update this code would be to replace the three
* partner info fields in hvcs_struct with a list of hvcs_partner_info
* instances.
*
* This function must be called with the hvcsd->lock held.
*/
static int hvcs_get_pi(struct hvcs_struct *hvcsd)
{
struct hvcs_partner_info *pi;
uint32_t unit_address = hvcsd->vdev->unit_address;
struct list_head head;
int retval;
spin_lock(&hvcs_pi_lock);
if (!hvcs_pi_buff) {
spin_unlock(&hvcs_pi_lock);
return -EFAULT;
}
retval = hvcs_get_partner_info(unit_address, &head, hvcs_pi_buff);
spin_unlock(&hvcs_pi_lock);
if (retval) {
printk(KERN_ERR "HVCS: Failed to fetch partner"
" info for vty-server@%x.\n", unit_address);
return retval;
}
/* nixes the values if the partner vty went away */
hvcsd->p_unit_address = 0;
hvcsd->p_partition_ID = 0;
list_for_each_entry(pi, &head, node)
hvcs_set_pi(pi, hvcsd);
hvcs_free_partner_info(&head);
return 0;
}
/*
* This function is executed by the driver "rescan" sysfs entry. It shouldn't
* be executed elsewhere, in order to prevent deadlock issues.
*/
static int hvcs_rescan_devices_list(void)
{
struct hvcs_struct *hvcsd;
unsigned long flags;
spin_lock(&hvcs_structs_lock);
list_for_each_entry(hvcsd, &hvcs_structs, next) {
spin_lock_irqsave(&hvcsd->lock, flags);
hvcs_get_pi(hvcsd);
spin_unlock_irqrestore(&hvcsd->lock, flags);
}
spin_unlock(&hvcs_structs_lock);
return 0;
}
/*
* Farm this off into its own function because it could be more complex once
* multiple partners support is added. This function should be called with
* the hvcsd->lock held.
*/
static int hvcs_has_pi(struct hvcs_struct *hvcsd)
{
if ((!hvcsd->p_unit_address) || (!hvcsd->p_partition_ID))
return 0;
return 1;
}
/*
* NOTE: It is possible that the super admin removed a partner vty and then
* added a different vty as the new partner.
*
* This function must be called with the hvcsd->lock held.
*/
static int hvcs_partner_connect(struct hvcs_struct *hvcsd)
{
int retval;
unsigned int unit_address = hvcsd->vdev->unit_address;
/*
* If there wasn't any pi when the device was added it doesn't meant
* there isn't any now. This driver isn't notified when a new partner
* vty is added to a vty-server so we discover changes on our own.
* Please see comments in hvcs_register_connection() for justification
* of this bizarre code.
*/
retval = hvcs_register_connection(unit_address,
hvcsd->p_partition_ID,
hvcsd->p_unit_address);
if (!retval) {
hvcsd->connected = 1;
return 0;
} else if (retval != -EINVAL)
return retval;
/*
* As per the spec re-get the pi and try again if -EINVAL after the
* first connection attempt.
*/
if (hvcs_get_pi(hvcsd))
return -ENOMEM;
if (!hvcs_has_pi(hvcsd))
return -ENODEV;
retval = hvcs_register_connection(unit_address,
hvcsd->p_partition_ID,
hvcsd->p_unit_address);
if (retval != -EINVAL) {
hvcsd->connected = 1;
return retval;
}
/*
* EBUSY is the most likely scenario though the vty could have been
* removed or there really could be an hcall error due to the parameter
* data but thanks to ambiguous firmware return codes we can't really
* tell.
*/
printk(KERN_INFO "HVCS: vty-server or partner"
" vty is busy. Try again later.\n");
return -EBUSY;
}
/* This function must be called with the hvcsd->lock held */
static void hvcs_partner_free(struct hvcs_struct *hvcsd)
{
int retval;
do {
retval = hvcs_free_connection(hvcsd->vdev->unit_address);
} while (retval == -EBUSY);
hvcsd->connected = 0;
}
/* This helper function must be called WITHOUT the hvcsd->lock held */
static int hvcs_enable_device(struct hvcs_struct *hvcsd, uint32_t unit_address,
unsigned int irq, struct vio_dev *vdev)
{
unsigned long flags;
int rc;
/*
* It is possible that the vty-server was removed between the time that
* the conn was registered and now.
*/
if (!(rc = request_irq(irq, &hvcs_handle_interrupt,
SA_INTERRUPT, "ibmhvcs", hvcsd))) {
/*
* It is possible the vty-server was removed after the irq was
* requested but before we have time to enable interrupts.
*/
if (vio_enable_interrupts(vdev) == H_Success)
return 0;
else {
printk(KERN_ERR "HVCS: int enable failed for"
" vty-server@%X.\n", unit_address);
free_irq(irq, hvcsd);
}
} else
printk(KERN_ERR "HVCS: irq req failed for"
" vty-server@%X.\n", unit_address);
spin_lock_irqsave(&hvcsd->lock, flags);
hvcs_partner_free(hvcsd);
spin_unlock_irqrestore(&hvcsd->lock, flags);
return rc;
}
/*
* This always increments the kobject ref count if the call is successful.
* Please remember to dec when you are done with the instance.
*
* NOTICE: Do NOT hold either the hvcs_struct.lock or hvcs_structs_lock when
* calling this function or you will get deadlock.
*/
struct hvcs_struct *hvcs_get_by_index(int index)
{
struct hvcs_struct *hvcsd = NULL;
unsigned long flags;
spin_lock(&hvcs_structs_lock);
/* We can immediately discard OOB requests */
if (index >= 0 && index < HVCS_MAX_SERVER_ADAPTERS) {
list_for_each_entry(hvcsd, &hvcs_structs, next) {
spin_lock_irqsave(&hvcsd->lock, flags);
if (hvcsd->index == index) {
kobject_get(&hvcsd->kobj);
spin_unlock_irqrestore(&hvcsd->lock, flags);
spin_unlock(&hvcs_structs_lock);
return hvcsd;
}
spin_unlock_irqrestore(&hvcsd->lock, flags);
}
hvcsd = NULL;
}
spin_unlock(&hvcs_structs_lock);
return hvcsd;
}
/*
* This is invoked via the tty_open interface when a user app connects to the
* /dev node.
*/
static int hvcs_open(struct tty_struct *tty, struct file *filp)
{
struct hvcs_struct *hvcsd;
int rc, retval = 0;
unsigned long flags;
unsigned int irq;
struct vio_dev *vdev;
unsigned long unit_address;
struct kobject *kobjp;
if (tty->driver_data)
goto fast_open;
/*
* Is there a vty-server that shares the same index?
* This function increments the kobject index.
*/
if (!(hvcsd = hvcs_get_by_index(tty->index))) {
printk(KERN_WARNING "HVCS: open failed, no device associated"
" with tty->index %d.\n", tty->index);
return -ENODEV;
}
spin_lock_irqsave(&hvcsd->lock, flags);
if (hvcsd->connected == 0)
if ((retval = hvcs_partner_connect(hvcsd)))
goto error_release;
hvcsd->open_count = 1;
hvcsd->tty = tty;
tty->driver_data = hvcsd;
/*
* Set this driver to low latency so that we actually have a chance at
* catching a throttled TTY after we flip_buffer_push. Otherwise the
* flush_to_async may not execute until after the kernel_thread has
* yielded and resumed the next flip_buffer_push resulting in data
* loss.
*/