| // 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.rst. |
| */ |
| |
| #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"; |
| |
| /* 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 int hvcs_get_pi(struct hvcs_struct *hvcsd); |
| static int hvcs_rescan_devices_list(void); |
| |
| static void hvcs_partner_free(struct hvcs_struct *hvcsd); |
| |
| 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 -- FIXME :js: it is not! */ |
| 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 void hvcs_remove(struct vio_dev *dev) |
| { |
| struct hvcs_struct *hvcsd = dev_get_drvdata(&dev->dev); |
| unsigned long flags; |
| struct tty_struct *tty; |
| |
| /* 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); |
| }; |
| |
| 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, pi->location_code, |
| 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 unsigned 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 unsigned 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); |