diff options
Diffstat (limited to 'drivers/tty/hvc/hvcs.c')
| -rw-r--r-- | drivers/tty/hvc/hvcs.c | 1602 |
1 files changed, 1602 insertions, 0 deletions
diff --git a/drivers/tty/hvc/hvcs.c b/drivers/tty/hvc/hvcs.c new file mode 100644 index 000000000..7853c6375 --- /dev/null +++ b/drivers/tty/hvc/hvcs.c @@ -0,0 +1,1602 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * IBM eServer Hypervisor Virtual Console Server Device Driver + * Copyright (C) 2003, 2004 IBM Corp. + * Ryan S. Arnold (rsa@us.ibm.com) + * + * 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 kref construct. + * + * 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/kref.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/slab.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 <linux/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/powerepc/include/asm/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 similarly 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/powerpc/platforms/pseries/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 const struct ktermios hvcs_tty_termios = { + .c_iflag = IGNBRK | IGNPAR, + .c_oflag = OPOST, + .c_cflag = B38400 | CS8 | CREAD | HUPCL, + .c_cc = INIT_C_CC, + .c_ispeed = 38400, + .c_ospeed = 38400 +}; + +/* + * 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); + +static const char hvcs_driver_name[] = "hvcs"; +static const char hvcs_device_node[] = "hvcs"; +static const 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 { + struct tty_port port; + spinlock_t lock; + + /* + * This index identifies this hvcs device as the complement to a + * specific tty index. + */ + unsigned int index; + + /* + * 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 is valid before a tty is connected and + * stays valid after the tty is disconnected. These shouldn't be + * whacked until the kobject refcount reaches zero though some entries + * may be changed via sysfs initiatives. + */ + 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; +}; + +static LIST_HEAD(hvcs_structs); +static DEFINE_SPINLOCK(hvcs_structs_lock); +static DEFINE_MUTEX(hvcs_init_mutex); + +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); + +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 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 int hvcs_probe(struct vio_dev *dev, + const struct vio_device_id *id); +static int hvcs_remove(struct vio_dev *dev); +static int __init hvcs_module_init(void); +static void __exit hvcs_module_exit(void); +static int hvcs_initialize(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 inline struct hvcs_struct *from_vio_dev(struct vio_dev *viod) +{ + return dev_get_drvdata(&viod->dev); +} +/* The sysfs interface for the driver and devices */ + +static ssize_t hvcs_partner_vtys_show(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct vio_dev *viod = to_vio_dev(dev); + struct hvcs_struct *hvcsd = from_vio_dev(viod); + unsigned long flags; + int retval; + + spin_lock_irqsave(&hvcsd->lock, flags); + retval = sprintf(buf, "%X\n", hvcsd->p_unit_address); + spin_unlock_irqrestore(&hvcsd->lock, flags); + return retval; +} +static DEVICE_ATTR(partner_vtys, S_IRUGO, hvcs_partner_vtys_show, NULL); + +static ssize_t hvcs_partner_clcs_show(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct vio_dev *viod = to_vio_dev(dev); + struct hvcs_struct *hvcsd = from_vio_dev(viod); + unsigned long flags; + int retval; + + spin_lock_irqsave(&hvcsd->lock, flags); + retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]); + spin_unlock_irqrestore(&hvcsd->lock, flags); + return retval; +} +static DEVICE_ATTR(partner_clcs, S_IRUGO, hvcs_partner_clcs_show, NULL); + +static ssize_t hvcs_current_vty_store(struct device *dev, struct device_attribute *attr, const char * buf, + size_t count) +{ + /* + * Don't need this feature at the present time because firmware doesn't + * yet support multiple partners. + */ + printk(KERN_INFO "HVCS: Denied current_vty change: -EPERM.\n"); + return -EPERM; +} + +static ssize_t hvcs_current_vty_show(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct vio_dev *viod = to_vio_dev(dev); + struct hvcs_struct *hvcsd = from_vio_dev(viod); + unsigned long flags; + int retval; + + spin_lock_irqsave(&hvcsd->lock, flags); + retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]); + spin_unlock_irqrestore(&hvcsd->lock, flags); + return retval; +} + +static DEVICE_ATTR(current_vty, + S_IRUGO | S_IWUSR, hvcs_current_vty_show, hvcs_current_vty_store); + +static ssize_t hvcs_vterm_state_store(struct device *dev, struct device_attribute *attr, const char *buf, + size_t count) +{ + struct vio_dev *viod = to_vio_dev(dev); + struct hvcs_struct *hvcsd = from_vio_dev(viod); + unsigned long flags; + + /* writing a '0' to this sysfs entry will result in the disconnect. */ + if (simple_strtol(buf, NULL, 0) != 0) + return -EINVAL; + + spin_lock_irqsave(&hvcsd->lock, flags); + + if (hvcsd->port.count > 0) { + spin_unlock_irqrestore(&hvcsd->lock, flags); + printk(KERN_INFO "HVCS: vterm state unchanged. " + "The hvcs device node is still in use.\n"); + return -EPERM; + } + + if (hvcsd->connected == 0) { + spin_unlock_irqrestore(&hvcsd->lock, flags); + printk(KERN_INFO "HVCS: vterm state unchanged. The" + " vty-server is not connected to a vty.\n"); + return -EPERM; + } + + 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); + + spin_unlock_irqrestore(&hvcsd->lock, flags); + return count; +} + +static ssize_t hvcs_vterm_state_show(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct vio_dev *viod = to_vio_dev(dev); + struct hvcs_struct *hvcsd = from_vio_dev(viod); + unsigned long flags; + int retval; + + spin_lock_irqsave(&hvcsd->lock, flags); + retval = sprintf(buf, "%d\n", hvcsd->connected); + spin_unlock_irqrestore(&hvcsd->lock, flags); + return retval; +} +static DEVICE_ATTR(vterm_state, S_IRUGO | S_IWUSR, + hvcs_vterm_state_show, hvcs_vterm_state_store); + +static ssize_t hvcs_index_show(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct vio_dev *viod = to_vio_dev(dev); + struct hvcs_struct *hvcsd = from_vio_dev(viod); + unsigned long flags; + int retval; + + spin_lock_irqsave(&hvcsd->lock, flags); + retval = sprintf(buf, "%d\n", hvcsd->index); + spin_unlock_irqrestore(&hvcsd->lock, flags); + return retval; +} + +static DEVICE_ATTR(index, S_IRUGO, hvcs_index_show, NULL); + +static struct attribute *hvcs_attrs[] = { + &dev_attr_partner_vtys.attr, + &dev_attr_partner_clcs.attr, + &dev_attr_current_vty.attr, + &dev_attr_vterm_state.attr, + &dev_attr_index.attr, + NULL, +}; + +static struct attribute_group hvcs_attr_group = { + .attrs = hvcs_attrs, +}; + +static ssize_t rescan_show(struct device_driver *ddp, char *buf) +{ + /* A 1 means it is updating, a 0 means it is done updating */ + return snprintf(buf, PAGE_SIZE, "%d\n", hvcs_rescan_status); +} + +static ssize_t rescan_store(struct device_driver *ddp, const char * buf, + size_t count) +{ + if ((simple_strtol(buf, NULL, 0) != 1) + && (hvcs_rescan_status != 0)) + return -EINVAL; + + hvcs_rescan_status = 1; + printk(KERN_INFO "HVCS: rescanning partner info for all" + " vty-servers.\n"); + hvcs_rescan_devices_list(); + hvcs_rescan_status = 0; + return count; +} + +static DRIVER_ATTR_RW(rescan); + +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 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->port.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 committed 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; + + spin_lock_irqsave(&hvcsd->lock, flags); + + unit_address = hvcsd->vdev->unit_address; + tty = hvcsd->port.tty; + + hvcs_try_write(hvcsd); + + if (!tty || tty_throttled(tty)) { + 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_buffer_request_room(&hvcsd->port, HVCS_BUFF_LEN) >= HVCS_BUFF_LEN) { + got = hvc_get_chars(unit_address, + &buf[0], + HVCS_BUFF_LEN); + tty_insert_flip_string(&hvcsd->port, buf, got); + } + + /* 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); + /* This is synch because tty->low_latency == 1 */ + if(got) + tty_flip_buffer_push(&hvcsd->port); + + 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 const struct vio_device_id hvcs_driver_table[] = { + {"serial-server", "hvterm2"}, + { "", "" } +}; +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; +} + +static void hvcs_destruct_port(struct tty_port *p) +{ + struct hvcs_struct *hvcsd = container_of(p, struct hvcs_struct, port); + 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); + + sysfs_remove_group(&vdev->dev.kobj, &hvcs_attr_group); + + kfree(hvcsd); +} + +static const struct tty_port_operations hvcs_port_ops = { + .destruct = hvcs_destruct_port, +}; + +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 hvcs_probe( + struct vio_dev *dev, + const struct vio_device_id *id) +{ + struct hvcs_struct *hvcsd; + int index, rc; + int retval; + + if (!dev || !id) { + printk(KERN_ERR "HVCS: probed with invalid parameter.\n"); + return -EPERM; + } + + /* Make sure we are properly initialized */ + rc = hvcs_initialize(); + if (rc) { + pr_err("HVCS: Failed to initialize core driver.\n"); + return rc; + } + + /* early to avoid cleanup on failure */ + index = hvcs_get_index(); + if (index < 0) { + return -EFAULT; + } + + hvcsd = kzalloc(sizeof(*hvcsd), GFP_KERNEL); + if (!hvcsd) + return -ENODEV; + + tty_port_init(&hvcsd->port); + hvcsd->port.ops = &hvcs_port_ops; + spin_lock_init(&hvcsd->lock); + + hvcsd->vdev = dev; + dev_set_drvdata(&dev->dev, 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); + + retval = sysfs_create_group(&dev->dev.kobj, &hvcs_attr_group); + if (retval) { + printk(KERN_ERR "HVCS: Can't create sysfs attrs for vty-server@%X\n", + hvcsd->vdev->unit_address); + return retval; + } + + 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 hvcs_remove(struct vio_dev *dev) +{ + struct hvcs_struct *hvcsd = dev_get_drvdata(&dev->dev); + unsigned long flags; + struct tty_struct *tty; + + if (!hvcsd) + return -ENODEV; + + /* By this time the vty-server won't be getting any more interrupts */ + + spin_lock_irqsave(&hvcsd->lock, flags); + + tty = hvcsd->port.tty; + + 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. + */ + tty_port_put(&hvcsd->port); + + /* + * 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 = { + .id_table = hvcs_driver_table, + .probe = hvcs_probe, + .remove = hvcs_remove, + .name = hvcs_driver_name, +}; + +/* Only called from hvcs_get_pi please */ +static void hvcs_set_pi(struct hvcs_partner_info *pi, struct hvcs_struct *hvcsd) +{ + hvcsd->p_unit_address = pi->unit_address; + hvcsd->p_partition_ID = pi->partition_ID; + + /* copy the null-term char too */ + strlcpy(&hvcsd->p_location_code[0], + &pi->location_code[0], sizeof(hvcsd->p_location_code)); +} + +/* + * 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. + */ + rc = request_irq(irq, &hvcs_handle_interrupt, 0, "ibmhvcs", hvcsd); + if (!rc) { + /* + * 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 kref 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. + */ +static struct hvcs_struct *hvcs_get_by_index(int index) +{ + 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); + if (hvcsd->index == index) { + tty_port_get(&hvcsd->port); + spin_unlock_irqrestore(&hvcsd->lock, flags); + spin_unlock(&hvcs_structs_lock); + return hvcsd; + } + spin_unlock_irqrestore(&hvcsd->lock, flags); + } + spin_unlock(&hvcs_structs_lock); + + return NULL; +} + +static int hvcs_install(struct tty_driver *driver, struct tty_struct *tty) +{ + struct hvcs_struct *hvcsd; + struct vio_dev *vdev; + unsigned long unit_address, flags; + unsigned int irq; + int retval; + + /* + * Is there a vty-server that shares the same index? + * This function increments the kref index. + */ + hvcsd = hvcs_get_by_index(tty->index); + if (!hvcsd) { + 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) { + retval = hvcs_partner_connect(hvcsd); + if (retval) { + spin_unlock_irqrestore(&hvcsd->lock, flags); + printk(KERN_WARNING "HVCS: partner connect failed.\n"); + goto err_put; + } + } + + hvcsd->port.count = 0; + hvcsd->port.tty = tty; + tty->driver_data = hvcsd; + + memset(&hvcsd->buffer[0], 0x00, HVCS_BUFF_LEN); + + /* + * Save these in the spinlock for the enable operations that need them + * outside of the spinlock. + */ + irq = hvcsd->vdev->irq; + vdev = hvcsd->vdev; + unit_address = hvcsd->vdev->unit_address; + + hvcsd->todo_mask |= HVCS_SCHED_READ; + spin_unlock_irqrestore(&hvcsd->lock, flags); + + /* + * This must be done outside of the spinlock because it requests irqs + * and will grab the spinlock and free the connection if it fails. + */ + retval = hvcs_enable_device(hvcsd, unit_address, irq, vdev); + if (retval) { + printk(KERN_WARNING "HVCS: enable device failed.\n"); + goto err_put; + } + + retval = tty_port_install(&hvcsd->port, driver, tty); + if (retval) + goto err_irq; + + return 0; +err_irq: + spin_lock_irqsave(&hvcsd->lock, flags); + vio_disable_interrupts(hvcsd->vdev); + spin_unlock_irqrestore(&hvcsd->lock, flags); + free_irq(irq, hvcsd); +err_put: + tty_port_put(&hvcsd->port); + + return retval; +} + +/* + * 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 = tty->driver_data; + unsigned long flags; + + spin_lock_irqsave(&hvcsd->lock, flags); + hvcsd->port.count++; + hvcsd->todo_mask |= HVCS_SCHED_READ; + spin_unlock_irqrestore(&hvcsd->lock, flags); + + hvcs_kick(); + + printk(KERN_INFO "HVCS: vty-server@%X connection opened.\n", + hvcsd->vdev->unit_address ); + + return 0; +} + +static void hvcs_close(struct tty_struct *tty, struct file *filp) +{ + struct hvcs_struct *hvcsd; + unsigned long flags; + int irq; + + /* + * Is someone trying to close the file associated with this device after + * we have hung up? If so tty->driver_data wouldn't be valid. + */ + if (tty_hung_up_p(filp)) + return; + + /* + * No driver_data means that this close was probably issued after a + * failed hvcs_open by the tty layer's release_dev() api and we can just + * exit cleanly. + */ + if (!tty->driver_data) + return; + + hvcsd = tty->driver_data; + + spin_lock_irqsave(&hvcsd->lock, flags); + if (--hvcsd->port.count == 0) { + + vio_disable_interrupts(hvcsd->vdev); + + /* + * NULL this early so that the kernel_thread doesn't try to + * execute any operations on the TTY even though it is obligated + * to deliver any pending I/O to the hypervisor. + */ + hvcsd->port.tty = NULL; + + irq = hvcsd->vdev->irq; + spin_unlock_irqrestore(&hvcsd->lock, flags); + + tty_wait_until_sent(tty, HVCS_CLOSE_WAIT); + + free_irq(irq, hvcsd); + return; + } else if (hvcsd->port.count < 0) { + printk(KERN_ERR "HVCS: vty-server@%X open_count: %d is mismanaged.\n", + hvcsd->vdev->unit_address, hvcsd->port.count); + } + + spin_unlock_irqrestore(&hvcsd->lock, flags); +} + +static void hvcs_cleanup(struct tty_struct * tty) +{ + struct hvcs_struct *hvcsd = tty->driver_data; + + /* + * This line is important because it tells hvcs_open that this + * device needs to be re-configured the next time hvcs_open is + * called. + */ + tty->driver_data = NULL; + + tty_port_put(&hvcsd->port); +} + +static void hvcs_hangup(struct tty_struct * tty) +{ + struct hvcs_struct *hvcsd = tty->driver_data; + unsigned long flags; + int temp_open_count; + int irq; + + spin_lock_irqsave(&hvcsd->lock, flags); + /* Preserve this so that we know how many kref refs to put */ + temp_open_count = hvcsd->port.count; + + /* + * Don't kref put inside the spinlock because the destruction + * callback may use the spinlock and it may get called before the + * spinlock has been released. + */ + vio_disable_interrupts(hvcsd->vdev); + + hvcsd->todo_mask = 0; + + /* I don't think the tty needs the hvcs_struct pointer after a hangup */ + tty->driver_data = NULL; + hvcsd->port.tty = NULL; + + hvcsd->port.count = 0; + + /* This will drop any buffered data on the floor which is OK in a hangup + * scenario. */ + memset(&hvcsd->buffer[0], 0x00, HVCS_BUFF_LEN); + hvcsd->chars_in_buffer = 0; + + irq = hvcsd->vdev->irq; + + spin_unlock_irqrestore(&hvcsd->lock, flags); + + free_irq(irq, hvcsd); + + /* + * We need to kref_put() for every open_count we have since the + * tty_hangup() function doesn't invoke a close per open connection on a + * non-console device. + */ + while(temp_open_count) { + --temp_open_count; + /* + * The final put will trigger destruction of the hvcs_struct. + * NOTE: If this hangup was signaled from user space then the + * final put will never happen. + */ + tty_port_put(&hvcsd->port); + } +} + +/* + * NOTE: This is almost always from_user since user level apps interact with the + * /dev nodes. I'm trusting that if hvcs_write gets called and interrupted by + * hvcs_remove (which removes the target device and executes tty_hangup()) that + * tty_hangup will allow hvcs_write time to complete execution before it + * terminates our device. + */ +static int hvcs_write(struct tty_struct *tty, + const unsigned char *buf, int count) +{ + struct hvcs_struct *hvcsd = tty->driver_data; + unsigned int unit_address; + const unsigned char *charbuf; + unsigned long flags; + int total_sent = 0; + int tosend = 0; + int result = 0; + + /* + * If they don't check the return code off of their open they may + * attempt this even if there is no connected device. + */ + if (!hvcsd) + return -ENODEV; + + /* Reasonable size to prevent user level flooding */ + if (count > HVCS_MAX_FROM_USER) { + printk(KERN_WARNING "HVCS write: count being truncated to" + " HVCS_MAX_FROM_USER.\n"); + count = HVCS_MAX_FROM_USER; + } + + charbuf = buf; + + spin_lock_irqsave(&hvcsd->lock, flags); + + /* + * Somehow an open succeeded but the device was removed or the + * connection terminated between the vty-server and partner vty during + * the middle of a write operation? This is a crummy place to do this + * but we want to keep it all in the spinlock. + */ + if (hvcsd->port.count <= 0) { + spin_unlock_irqrestore(&hvcsd->lock, flags); + return -ENODEV; + } + + unit_address = hvcsd->vdev->unit_address; + + while (count > 0) { + tosend = min(count, (HVCS_BUFF_LEN - hvcsd->chars_in_buffer)); + /* + * No more space, this probably means that the last call to + * hvcs_write() didn't succeed and the buffer was filled up. + */ + if (!tosend) + break; + + memcpy(&hvcsd->buffer[hvcsd->chars_in_buffer], + &charbuf[total_sent], + tosend); + + hvcsd->chars_in_buffer += tosend; + + result = 0; + + /* + * If this is true then we don't want to try writing to the + * hypervisor because that is the kernel_threads job now. We'll + * just add to the buffer. + */ + if (!(hvcsd->todo_mask & HVCS_TRY_WRITE)) + /* won't send partial writes */ + result = hvc_put_chars(unit_address, + &hvcsd->buffer[0], + hvcsd->chars_in_buffer); + + /* + * Since we know we have enough room in hvcsd->buffer for + * tosend we record that it was sent regardless of whether the + * hypervisor actually took it because we have it buffered. + */ + total_sent+=tosend; + count-=tosend; + if (result == 0) { + hvcsd->todo_mask |= HVCS_TRY_WRITE; + hvcs_kick(); + break; + } + + hvcsd->chars_in_buffer = 0; + /* + * Test after the chars_in_buffer reset otherwise this could + * deadlock our writes if hvc_put_chars fails. + */ + if (result < 0) + break; + } + + spin_unlock_irqrestore(&hvcsd->lock, flags); + + if (result == -1) + return -EIO; + else + return total_sent; +} + +/* + * This is really asking how much can we guarantee that we can send or that we + * absolutely WILL BUFFER if we can't send it. This driver MUST honor the + * return value, hence the reason for hvcs_struct buffering. + */ +static int hvcs_write_room(struct tty_struct *tty) +{ + struct hvcs_struct *hvcsd = tty->driver_data; + + if (!hvcsd || hvcsd->port.count <= 0) + return 0; + + return HVCS_BUFF_LEN - hvcsd->chars_in_buffer; +} + +static int hvcs_chars_in_buffer(struct tty_struct *tty) +{ + struct hvcs_struct *hvcsd = tty->driver_data; + + return hvcsd->chars_in_buffer; +} + +static const struct tty_operations hvcs_ops = { + .install = hvcs_install, + .open = hvcs_open, + .close = hvcs_close, + .cleanup = hvcs_cleanup, + .hangup = hvcs_hangup, + .write = hvcs_write, + .write_room = hvcs_write_room, + .chars_in_buffer = hvcs_chars_in_buffer, + .unthrottle = hvcs_unthrottle, + .throttle = hvcs_throttle, +}; + +static int hvcs_alloc_index_list(int n) +{ + int i; + + hvcs_index_list = kmalloc_array(n, sizeof(hvcs_index_count), + GFP_KERNEL); + if (!hvcs_index_list) + return -ENOMEM; + hvcs_index_count = n; + for (i = 0; i < hvcs_index_count; i++) + hvcs_index_list[i] = -1; + return 0; +} + +static void hvcs_free_index_list(void) +{ + /* Paranoia check to be thorough. */ + kfree(hvcs_index_list); + hvcs_index_list = NULL; + hvcs_index_count = 0; +} + +static int hvcs_initialize(void) +{ + int rc, num_ttys_to_alloc; + + mutex_lock(&hvcs_init_mutex); + if (hvcs_task) { + mutex_unlock(&hvcs_init_mutex); + return 0; + } + + /* Has the user specified an overload with an insmod param? */ + if (hvcs_parm_num_devs <= 0 || + (hvcs_parm_num_devs > HVCS_MAX_SERVER_ADAPTERS)) { + num_ttys_to_alloc = HVCS_DEFAULT_SERVER_ADAPTERS; + } else + num_ttys_to_alloc = hvcs_parm_num_devs; + + hvcs_tty_driver = alloc_tty_driver(num_ttys_to_alloc); + if (!hvcs_tty_driver) { + mutex_unlock(&hvcs_init_mutex); + return -ENOMEM; + } + + if (hvcs_alloc_index_list(num_ttys_to_alloc)) { + rc = -ENOMEM; + goto index_fail; + } + + hvcs_tty_driver->driver_name = hvcs_driver_name; + hvcs_tty_driver->name = hvcs_device_node; + + /* + * We'll let the system assign us a major number, indicated by leaving + * it blank. + */ + + hvcs_tty_driver->minor_start = HVCS_MINOR_START; + hvcs_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM; + + /* + * We role our own so that we DONT ECHO. We can't echo because the + * device we are connecting to already echoes by default and this would + * throw us into a horrible recursive echo-echo-echo loop. + */ + hvcs_tty_driver->init_termios = hvcs_tty_termios; + hvcs_tty_driver->flags = TTY_DRIVER_REAL_RAW; + + tty_set_operations(hvcs_tty_driver, &hvcs_ops); + + /* + * The following call will result in sysfs entries that denote the + * dynamically assigned major and minor numbers for our devices. + */ + if (tty_register_driver(hvcs_tty_driver)) { + printk(KERN_ERR "HVCS: registration as a tty driver failed.\n"); + rc = -EIO; + goto register_fail; + } + + hvcs_pi_buff = (unsigned long *) __get_free_page(GFP_KERNEL); + if (!hvcs_pi_buff) { + rc = -ENOMEM; + goto buff_alloc_fail; + } + + hvcs_task = kthread_run(khvcsd, NULL, "khvcsd"); + if (IS_ERR(hvcs_task)) { + printk(KERN_ERR "HVCS: khvcsd creation failed.\n"); + rc = -EIO; + goto kthread_fail; + } + mutex_unlock(&hvcs_init_mutex); + return 0; + +kthread_fail: + free_page((unsigned long)hvcs_pi_buff); +buff_alloc_fail: + tty_unregister_driver(hvcs_tty_driver); +register_fail: + hvcs_free_index_list(); +index_fail: + put_tty_driver(hvcs_tty_driver); + hvcs_tty_driver = NULL; + mutex_unlock(&hvcs_init_mutex); + return rc; +} + +static int __init hvcs_module_init(void) +{ + int rc = vio_register_driver(&hvcs_vio_driver); + if (rc) { + printk(KERN_ERR "HVCS: can't register vio driver\n"); + return rc; + } + + pr_info("HVCS: Driver registered.\n"); + + /* This needs to be done AFTER the vio_register_driver() call or else + * the kobjects won't be initialized properly. + */ + rc = driver_create_file(&(hvcs_vio_driver.driver), &driver_attr_rescan); + if (rc) + pr_warn("HVCS: Failed to create rescan file (err %d)\n", rc); + + return 0; +} + +static void __exit hvcs_module_exit(void) +{ + /* + * This driver receives hvcs_remove callbacks for each device upon + * module removal. + */ + vio_unregister_driver(&hvcs_vio_driver); + if (!hvcs_task) + return; + + /* + * This synchronous operation will wake the khvcsd kthread if it is + * asleep and will return when khvcsd has terminated. + */ + kthread_stop(hvcs_task); + + spin_lock(&hvcs_pi_lock); + free_page((unsigned long)hvcs_pi_buff); + hvcs_pi_buff = NULL; + spin_unlock(&hvcs_pi_lock); + + driver_remove_file(&hvcs_vio_driver.driver, &driver_attr_rescan); + + tty_unregister_driver(hvcs_tty_driver); + + hvcs_free_index_list(); + + put_tty_driver(hvcs_tty_driver); + + printk(KERN_INFO "HVCS: driver module removed.\n"); +} + +module_init(hvcs_module_init); +module_exit(hvcs_module_exit); |