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1603 lines
46 KiB
C
1603 lines
46 KiB
C
/*
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* IBM eServer Hypervisor Virtual Console Server Device Driver
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* Copyright (C) 2003, 2004 IBM Corp.
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* Ryan S. Arnold (rsa@us.ibm.com)
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* Author(s) : Ryan S. Arnold <rsa@us.ibm.com>
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*
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* This is the device driver for the IBM Hypervisor Virtual Console Server,
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* "hvcs". The IBM hvcs provides a tty driver interface to allow Linux
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* user space applications access to the system consoles of logically
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* partitioned operating systems, e.g. Linux, running on the same partitioned
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* Power5 ppc64 system. Physical hardware consoles per partition are not
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* practical on this hardware so system consoles are accessed by this driver
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* using inter-partition firmware interfaces to virtual terminal devices.
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*
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* A vty is known to the HMC as a "virtual serial server adapter". It is a
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* virtual terminal device that is created by firmware upon partition creation
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* to act as a partitioned OS's console device.
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*
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* Firmware dynamically (via hotplug) exposes vty-servers to a running ppc64
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* Linux system upon their creation by the HMC or their exposure during boot.
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* The non-user interactive backend of this driver is implemented as a vio
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* device driver so that it can receive notification of vty-server lifetimes
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* after it registers with the vio bus to handle vty-server probe and remove
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* callbacks.
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*
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* Many vty-servers can be configured to connect to one vty, but a vty can
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* only be actively connected to by a single vty-server, in any manner, at one
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* time. If the HMC is currently hosting the console for a target Linux
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* partition; attempts to open the tty device to the partition's console using
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* the hvcs on any partition will return -EBUSY with every open attempt until
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* the HMC frees the connection between its vty-server and the desired
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* partition's vty device. Conversely, a vty-server may only be connected to
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* a single vty at one time even though it may have several configured vty
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* partner possibilities.
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*
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* Firmware does not provide notification of vty partner changes to this
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* driver. This means that an HMC Super Admin may add or remove partner vtys
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* from a vty-server's partner list but the changes will not be signaled to
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* the vty-server. Firmware only notifies the driver when a vty-server is
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* added or removed from the system. To compensate for this deficiency, this
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* driver implements a sysfs update attribute which provides a method for
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* rescanning partner information upon a user's request.
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*
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* Each vty-server, prior to being exposed to this driver is reference counted
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* using the 2.6 Linux kernel kref construct.
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*
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* For direction on installation and usage of this driver please reference
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* Documentation/powerpc/hvcs.txt.
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*/
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#include <linux/device.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/kernel.h>
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#include <linux/kref.h>
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#include <linux/kthread.h>
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#include <linux/list.h>
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#include <linux/major.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/sched.h>
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#include <linux/spinlock.h>
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#include <linux/stat.h>
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#include <linux/tty.h>
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#include <linux/tty_flip.h>
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#include <asm/hvconsole.h>
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#include <asm/hvcserver.h>
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#include <asm/uaccess.h>
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#include <asm/vio.h>
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/*
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* 1.3.0 -> 1.3.1 In hvcs_open memset(..,0x00,..) instead of memset(..,0x3F,00).
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* Removed braces around single statements following conditionals. Removed '=
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* 0' after static int declarations since these default to zero. Removed
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* list_for_each_safe() and replaced with list_for_each_entry() in
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* hvcs_get_by_index(). The 'safe' version is un-needed now that the driver is
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* using spinlocks. Changed spin_lock_irqsave() to spin_lock() when locking
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* hvcs_structs_lock and hvcs_pi_lock since these are not touched in an int
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* handler. Initialized hvcs_structs_lock and hvcs_pi_lock to
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* SPIN_LOCK_UNLOCKED at declaration time rather than in hvcs_module_init().
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* Added spin_lock around list_del() in destroy_hvcs_struct() to protect the
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* list traversals from a deletion. Removed '= NULL' from pointer declaration
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* statements since they are initialized NULL by default. Removed wmb()
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* instances from hvcs_try_write(). They probably aren't needed with locking in
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* place. Added check and cleanup for hvcs_pi_buff = kmalloc() in
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* hvcs_module_init(). Exposed hvcs_struct.index via a sysfs attribute so that
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* the coupling between /dev/hvcs* and a vty-server can be automatically
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* determined. Moved kobject_put() in hvcs_open outside of the
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* spin_unlock_irqrestore().
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*
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* 1.3.1 -> 1.3.2 Changed method for determining hvcs_struct->index and had it
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* align with how the tty layer always assigns the lowest index available. This
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* change resulted in a list of ints that denotes which indexes are available.
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* Device additions and removals use the new hvcs_get_index() and
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* hvcs_return_index() helper functions. The list is created with
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* hvsc_alloc_index_list() and it is destroyed with hvcs_free_index_list().
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* Without these fixes hotplug vty-server adapter support goes crazy with this
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* driver if the user removes a vty-server adapter. Moved free_irq() outside of
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* the hvcs_final_close() function in order to get it out of the spinlock.
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* Rearranged hvcs_close(). Cleaned up some printks and did some housekeeping
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* on the changelog. Removed local CLC_LENGTH and used HVCS_CLC_LENGTH from
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* arch/powerepc/include/asm/hvcserver.h
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*
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* 1.3.2 -> 1.3.3 Replaced yield() in hvcs_close() with tty_wait_until_sent() to
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* prevent possible lockup with realtime scheduling as similarily pointed out by
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* akpm in hvc_console. Changed resulted in the removal of hvcs_final_close()
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* to reorder cleanup operations and prevent discarding of pending data during
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* an hvcs_close(). Removed spinlock protection of hvcs_struct data members in
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* hvcs_write_room() and hvcs_chars_in_buffer() because they aren't needed.
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*/
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#define HVCS_DRIVER_VERSION "1.3.3"
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MODULE_AUTHOR("Ryan S. Arnold <rsa@us.ibm.com>");
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MODULE_DESCRIPTION("IBM hvcs (Hypervisor Virtual Console Server) Driver");
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MODULE_LICENSE("GPL");
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MODULE_VERSION(HVCS_DRIVER_VERSION);
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/*
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* Wait this long per iteration while trying to push buffered data to the
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* hypervisor before allowing the tty to complete a close operation.
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*/
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#define HVCS_CLOSE_WAIT (HZ/100) /* 1/10 of a second */
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/*
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* Since the Linux TTY code does not currently (2-04-2004) support dynamic
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* addition of tty derived devices and we shouldn't allocate thousands of
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* tty_device pointers when the number of vty-server & vty partner connections
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* will most often be much lower than this, we'll arbitrarily allocate
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* HVCS_DEFAULT_SERVER_ADAPTERS tty_structs and cdev's by default when we
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* register the tty_driver. This can be overridden using an insmod parameter.
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*/
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#define HVCS_DEFAULT_SERVER_ADAPTERS 64
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/*
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* The user can't insmod with more than HVCS_MAX_SERVER_ADAPTERS hvcs device
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* nodes as a sanity check. Theoretically there can be over 1 Billion
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* vty-server & vty partner connections.
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*/
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#define HVCS_MAX_SERVER_ADAPTERS 1024
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/*
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* We let Linux assign us a major number and we start the minors at zero. There
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* is no intuitive mapping between minor number and the target vty-server
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* adapter except that each new vty-server adapter is always assigned to the
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* smallest minor number available.
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*/
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#define HVCS_MINOR_START 0
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/*
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* The hcall interface involves putting 8 chars into each of two registers.
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* We load up those 2 registers (in arch/powerpc/platforms/pseries/hvconsole.c)
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* by casting char[16] to long[2]. It would work without __ALIGNED__, but a
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* little (tiny) bit slower because an unaligned load is slower than aligned
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* load.
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*/
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#define __ALIGNED__ __attribute__((__aligned__(8)))
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/*
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* How much data can firmware send with each hvc_put_chars()? Maybe this
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* should be moved into an architecture specific area.
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*/
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#define HVCS_BUFF_LEN 16
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/*
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* This is the maximum amount of data we'll let the user send us (hvcs_write) at
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* once in a chunk as a sanity check.
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*/
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#define HVCS_MAX_FROM_USER 4096
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/*
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* Be careful when adding flags to this line discipline. Don't add anything
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* that will cause echoing or we'll go into recursive loop echoing chars back
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* and forth with the console drivers.
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*/
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static struct ktermios hvcs_tty_termios = {
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.c_iflag = IGNBRK | IGNPAR,
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.c_oflag = OPOST,
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.c_cflag = B38400 | CS8 | CREAD | HUPCL,
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.c_cc = INIT_C_CC,
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.c_ispeed = 38400,
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.c_ospeed = 38400
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};
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/*
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* This value is used to take the place of a command line parameter when the
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* module is inserted. It starts as -1 and stays as such if the user doesn't
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* specify a module insmod parameter. If they DO specify one then it is set to
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* the value of the integer passed in.
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*/
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static int hvcs_parm_num_devs = -1;
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module_param(hvcs_parm_num_devs, int, 0);
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static const char hvcs_driver_name[] = "hvcs";
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static const char hvcs_device_node[] = "hvcs";
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static const char hvcs_driver_string[]
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= "IBM hvcs (Hypervisor Virtual Console Server) Driver";
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/* Status of partner info rescan triggered via sysfs. */
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static int hvcs_rescan_status;
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static struct tty_driver *hvcs_tty_driver;
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/*
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* In order to be somewhat sane this driver always associates the hvcs_struct
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* index element with the numerically equal tty->index. This means that a
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* hotplugged vty-server adapter will always map to the lowest index valued
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* device node. If vty-servers were hotplug removed from the system and then
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* new ones added the new vty-server may have the largest slot number of all
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* the vty-server adapters in the partition but it may have the lowest dev node
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* index of all the adapters due to the hole left by the hotplug removed
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* adapter. There are a set of functions provided to get the lowest index for
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* a new device as well as return the index to the list. This list is allocated
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* with a number of elements equal to the number of device nodes requested when
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* the module was inserted.
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*/
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static int *hvcs_index_list;
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/*
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* How large is the list? This is kept for traversal since the list is
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* dynamically created.
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*/
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static int hvcs_index_count;
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/*
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* Used by the khvcsd to pick up I/O operations when the kernel_thread is
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* already awake but potentially shifted to TASK_INTERRUPTIBLE state.
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*/
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static int hvcs_kicked;
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/*
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* Use by the kthread construct for task operations like waking the sleeping
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* thread and stopping the kthread.
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*/
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static struct task_struct *hvcs_task;
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/*
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* We allocate this for the use of all of the hvcs_structs when they fetch
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* partner info.
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*/
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static unsigned long *hvcs_pi_buff;
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/* Only allow one hvcs_struct to use the hvcs_pi_buff at a time. */
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static DEFINE_SPINLOCK(hvcs_pi_lock);
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/* One vty-server per hvcs_struct */
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struct hvcs_struct {
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spinlock_t lock;
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/*
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* This index identifies this hvcs device as the complement to a
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* specific tty index.
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*/
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unsigned int index;
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struct tty_struct *tty;
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int open_count;
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/*
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* Used to tell the driver kernel_thread what operations need to take
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* place upon this hvcs_struct instance.
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*/
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int todo_mask;
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/*
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* This buffer is required so that when hvcs_write_room() reports that
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* it can send HVCS_BUFF_LEN characters that it will buffer the full
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* HVCS_BUFF_LEN characters if need be. This is essential for opost
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* writes since they do not do high level buffering and expect to be
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* able to send what the driver commits to sending buffering
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* [e.g. tab to space conversions in n_tty.c opost()].
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*/
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char buffer[HVCS_BUFF_LEN];
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int chars_in_buffer;
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/*
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* Any variable below the kref is valid before a tty is connected and
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* stays valid after the tty is disconnected. These shouldn't be
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* whacked until the koject refcount reaches zero though some entries
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* may be changed via sysfs initiatives.
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*/
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struct kref kref; /* ref count & hvcs_struct lifetime */
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int connected; /* is the vty-server currently connected to a vty? */
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uint32_t p_unit_address; /* partner unit address */
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uint32_t p_partition_ID; /* partner partition ID */
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char p_location_code[HVCS_CLC_LENGTH + 1]; /* CLC + Null Term */
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struct list_head next; /* list management */
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struct vio_dev *vdev;
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};
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/* Required to back map a kref to its containing object */
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#define from_kref(k) container_of(k, struct hvcs_struct, kref)
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static LIST_HEAD(hvcs_structs);
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static DEFINE_SPINLOCK(hvcs_structs_lock);
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static void hvcs_unthrottle(struct tty_struct *tty);
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static void hvcs_throttle(struct tty_struct *tty);
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static irqreturn_t hvcs_handle_interrupt(int irq, void *dev_instance);
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static int hvcs_write(struct tty_struct *tty,
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const unsigned char *buf, int count);
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static int hvcs_write_room(struct tty_struct *tty);
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static int hvcs_chars_in_buffer(struct tty_struct *tty);
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static int hvcs_has_pi(struct hvcs_struct *hvcsd);
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static void hvcs_set_pi(struct hvcs_partner_info *pi,
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struct hvcs_struct *hvcsd);
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static int hvcs_get_pi(struct hvcs_struct *hvcsd);
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static int hvcs_rescan_devices_list(void);
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static int hvcs_partner_connect(struct hvcs_struct *hvcsd);
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static void hvcs_partner_free(struct hvcs_struct *hvcsd);
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static int hvcs_enable_device(struct hvcs_struct *hvcsd,
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uint32_t unit_address, unsigned int irq, struct vio_dev *dev);
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static int hvcs_open(struct tty_struct *tty, struct file *filp);
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static void hvcs_close(struct tty_struct *tty, struct file *filp);
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static void hvcs_hangup(struct tty_struct * tty);
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static int __devinit hvcs_probe(struct vio_dev *dev,
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const struct vio_device_id *id);
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static int __devexit hvcs_remove(struct vio_dev *dev);
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static int __init hvcs_module_init(void);
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static void __exit hvcs_module_exit(void);
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#define HVCS_SCHED_READ 0x00000001
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#define HVCS_QUICK_READ 0x00000002
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#define HVCS_TRY_WRITE 0x00000004
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#define HVCS_READ_MASK (HVCS_SCHED_READ | HVCS_QUICK_READ)
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static inline struct hvcs_struct *from_vio_dev(struct vio_dev *viod)
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{
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return dev_get_drvdata(&viod->dev);
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}
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/* The sysfs interface for the driver and devices */
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static ssize_t hvcs_partner_vtys_show(struct device *dev, struct device_attribute *attr, char *buf)
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{
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struct vio_dev *viod = to_vio_dev(dev);
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struct hvcs_struct *hvcsd = from_vio_dev(viod);
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unsigned long flags;
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int retval;
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spin_lock_irqsave(&hvcsd->lock, flags);
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retval = sprintf(buf, "%X\n", hvcsd->p_unit_address);
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spin_unlock_irqrestore(&hvcsd->lock, flags);
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return retval;
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}
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static DEVICE_ATTR(partner_vtys, S_IRUGO, hvcs_partner_vtys_show, NULL);
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static ssize_t hvcs_partner_clcs_show(struct device *dev, struct device_attribute *attr, char *buf)
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{
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struct vio_dev *viod = to_vio_dev(dev);
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struct hvcs_struct *hvcsd = from_vio_dev(viod);
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unsigned long flags;
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int retval;
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spin_lock_irqsave(&hvcsd->lock, flags);
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retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]);
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spin_unlock_irqrestore(&hvcsd->lock, flags);
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return retval;
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}
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static DEVICE_ATTR(partner_clcs, S_IRUGO, hvcs_partner_clcs_show, NULL);
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static ssize_t hvcs_current_vty_store(struct device *dev, struct device_attribute *attr, const char * buf,
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size_t count)
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{
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/*
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* Don't need this feature at the present time because firmware doesn't
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* yet support multiple partners.
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*/
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printk(KERN_INFO "HVCS: Denied current_vty change: -EPERM.\n");
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return -EPERM;
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}
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static ssize_t hvcs_current_vty_show(struct device *dev, struct device_attribute *attr, char *buf)
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{
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struct vio_dev *viod = to_vio_dev(dev);
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struct hvcs_struct *hvcsd = from_vio_dev(viod);
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unsigned long flags;
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int retval;
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spin_lock_irqsave(&hvcsd->lock, flags);
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retval = sprintf(buf, "%s\n", &hvcsd->p_location_code[0]);
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spin_unlock_irqrestore(&hvcsd->lock, flags);
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return retval;
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}
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static DEVICE_ATTR(current_vty,
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S_IRUGO | S_IWUSR, hvcs_current_vty_show, hvcs_current_vty_store);
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static ssize_t hvcs_vterm_state_store(struct device *dev, struct device_attribute *attr, const char *buf,
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size_t count)
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{
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struct vio_dev *viod = to_vio_dev(dev);
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struct hvcs_struct *hvcsd = from_vio_dev(viod);
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unsigned long flags;
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/* writing a '0' to this sysfs entry will result in the disconnect. */
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if (simple_strtol(buf, NULL, 0) != 0)
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return -EINVAL;
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spin_lock_irqsave(&hvcsd->lock, flags);
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if (hvcsd->open_count > 0) {
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spin_unlock_irqrestore(&hvcsd->lock, flags);
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printk(KERN_INFO "HVCS: vterm state unchanged. "
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"The hvcs device node is still in use.\n");
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return -EPERM;
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}
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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 hvcs_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 hvcs_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(rescan,
|
|
S_IRUGO | S_IWUSR, hvcs_rescan_show, hvcs_rescan_store);
|
|
|
|
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->tty;
|
|
int sent;
|
|
|
|
if (hvcsd->todo_mask & HVCS_TRY_WRITE) {
|
|
/* won't send partial writes */
|
|
sent = hvc_put_chars(unit_address,
|
|
&hvcsd->buffer[0],
|
|
hvcsd->chars_in_buffer );
|
|
if (sent > 0) {
|
|
hvcsd->chars_in_buffer = 0;
|
|
/* wmb(); */
|
|
hvcsd->todo_mask &= ~(HVCS_TRY_WRITE);
|
|
/* wmb(); */
|
|
|
|
/*
|
|
* We are still obligated to deliver the data to the
|
|
* hypervisor even if the tty has been closed because
|
|
* we commited to delivering it. But don't try to wake
|
|
* a non-existent tty.
|
|
*/
|
|
if (tty) {
|
|
tty_wakeup(tty);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
static int hvcs_io(struct hvcs_struct *hvcsd)
|
|
{
|
|
uint32_t unit_address;
|
|
struct tty_struct *tty;
|
|
char buf[HVCS_BUFF_LEN] __ALIGNED__;
|
|
unsigned long flags;
|
|
int got = 0;
|
|
|
|
spin_lock_irqsave(&hvcsd->lock, flags);
|
|
|
|
unit_address = hvcsd->vdev->unit_address;
|
|
tty = hvcsd->tty;
|
|
|
|
hvcs_try_write(hvcsd);
|
|
|
|
if (!tty || test_bit(TTY_THROTTLED, &tty->flags)) {
|
|
hvcsd->todo_mask &= ~(HVCS_READ_MASK);
|
|
goto bail;
|
|
} else if (!(hvcsd->todo_mask & (HVCS_READ_MASK)))
|
|
goto bail;
|
|
|
|
/* remove the read masks */
|
|
hvcsd->todo_mask &= ~(HVCS_READ_MASK);
|
|
|
|
if (tty_buffer_request_room(tty, HVCS_BUFF_LEN) >= HVCS_BUFF_LEN) {
|
|
got = hvc_get_chars(unit_address,
|
|
&buf[0],
|
|
HVCS_BUFF_LEN);
|
|
tty_insert_flip_string(tty, 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(tty);
|
|
|
|
if (!got) {
|
|
/* Do this _after_ the flip_buffer_push */
|
|
spin_lock_irqsave(&hvcsd->lock, flags);
|
|
vio_enable_interrupts(hvcsd->vdev);
|
|
spin_unlock_irqrestore(&hvcsd->lock, flags);
|
|
}
|
|
|
|
return hvcsd->todo_mask;
|
|
|
|
bail:
|
|
spin_unlock_irqrestore(&hvcsd->lock, flags);
|
|
return hvcsd->todo_mask;
|
|
}
|
|
|
|
static int khvcsd(void *unused)
|
|
{
|
|
struct hvcs_struct *hvcsd;
|
|
int hvcs_todo_mask;
|
|
|
|
__set_current_state(TASK_RUNNING);
|
|
|
|
do {
|
|
hvcs_todo_mask = 0;
|
|
hvcs_kicked = 0;
|
|
wmb();
|
|
|
|
spin_lock(&hvcs_structs_lock);
|
|
list_for_each_entry(hvcsd, &hvcs_structs, next) {
|
|
hvcs_todo_mask |= hvcs_io(hvcsd);
|
|
}
|
|
spin_unlock(&hvcs_structs_lock);
|
|
|
|
/*
|
|
* If any of the hvcs adapters want to try a write or quick read
|
|
* don't schedule(), yield a smidgen then execute the hvcs_io
|
|
* thread again for those that want the write.
|
|
*/
|
|
if (hvcs_todo_mask & (HVCS_TRY_WRITE | HVCS_QUICK_READ)) {
|
|
yield();
|
|
continue;
|
|
}
|
|
|
|
set_current_state(TASK_INTERRUPTIBLE);
|
|
if (!hvcs_kicked)
|
|
schedule();
|
|
__set_current_state(TASK_RUNNING);
|
|
} while (!kthread_should_stop());
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct vio_device_id hvcs_driver_table[] __devinitdata= {
|
|
{"serial-server", "hvterm2"},
|
|
{ "", "" }
|
|
};
|
|
MODULE_DEVICE_TABLE(vio, hvcs_driver_table);
|
|
|
|
static void hvcs_return_index(int index)
|
|
{
|
|
/* Paranoia check */
|
|
if (!hvcs_index_list)
|
|
return;
|
|
if (index < 0 || index >= hvcs_index_count)
|
|
return;
|
|
if (hvcs_index_list[index] == -1)
|
|
return;
|
|
else
|
|
hvcs_index_list[index] = -1;
|
|
}
|
|
|
|
/* callback when the kref ref count reaches zero */
|
|
static void destroy_hvcs_struct(struct kref *kref)
|
|
{
|
|
struct hvcs_struct *hvcsd = from_kref(kref);
|
|
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 int hvcs_get_index(void)
|
|
{
|
|
int i;
|
|
/* Paranoia check */
|
|
if (!hvcs_index_list) {
|
|
printk(KERN_ERR "HVCS: hvcs_index_list NOT valid!.\n");
|
|
return -EFAULT;
|
|
}
|
|
/* Find the numerically lowest first free index. */
|
|
for(i = 0; i < hvcs_index_count; i++) {
|
|
if (hvcs_index_list[i] == -1) {
|
|
hvcs_index_list[i] = 0;
|
|
return i;
|
|
}
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
static int __devinit hvcs_probe(
|
|
struct vio_dev *dev,
|
|
const struct vio_device_id *id)
|
|
{
|
|
struct hvcs_struct *hvcsd;
|
|
int index;
|
|
int retval;
|
|
|
|
if (!dev || !id) {
|
|
printk(KERN_ERR "HVCS: probed with invalid parameter.\n");
|
|
return -EPERM;
|
|
}
|
|
|
|
/* early to avoid cleanup on failure */
|
|
index = hvcs_get_index();
|
|
if (index < 0) {
|
|
return -EFAULT;
|
|
}
|
|
|
|
hvcsd = kzalloc(sizeof(*hvcsd), GFP_KERNEL);
|
|
if (!hvcsd)
|
|
return -ENODEV;
|
|
|
|
|
|
spin_lock_init(&hvcsd->lock);
|
|
/* Automatically incs the refcount the first time */
|
|
kref_init(&hvcsd->kref);
|
|
|
|
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 __devexit 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->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.
|
|
*/
|
|
kref_put(&hvcsd->kref, destroy_hvcs_struct);
|
|
|
|
/*
|
|
* 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 = __devexit_p(hvcs_remove),
|
|
.driver = {
|
|
.name = hvcs_driver_name,
|
|
.owner = THIS_MODULE,
|
|
}
|
|
};
|
|
|
|
/* Only called from hvcs_get_pi please */
|
|
static void hvcs_set_pi(struct hvcs_partner_info *pi, struct hvcs_struct *hvcsd)
|
|
{
|
|
int clclength;
|
|
|
|
hvcsd->p_unit_address = pi->unit_address;
|
|
hvcsd->p_partition_ID = pi->partition_ID;
|
|
clclength = strlen(&pi->location_code[0]);
|
|
if (clclength > HVCS_CLC_LENGTH)
|
|
clclength = HVCS_CLC_LENGTH;
|
|
|
|
/* copy the null-term char too */
|
|
strncpy(&hvcsd->p_location_code[0],
|
|
&pi->location_code[0], clclength + 1);
|
|
}
|
|
|
|
/*
|
|
* Traverse the list and add the partner info that is found to the hvcs_struct
|
|
* struct entry. NOTE: At this time I know that partner info will return a
|
|
* single entry but in the future there may be multiple partner info entries per
|
|
* vty-server and you'll want to zero out that list and reset it. If for some
|
|
* reason you have an old version of this driver but there IS more than one
|
|
* partner info then hvcsd->p_* will hold the last partner info data from the
|
|
* firmware query. A good way to update this code would be to replace the three
|
|
* partner info fields in hvcs_struct with a list of hvcs_partner_info
|
|
* instances.
|
|
*
|
|
* This function must be called with the hvcsd->lock held.
|
|
*/
|
|
static int hvcs_get_pi(struct hvcs_struct *hvcsd)
|
|
{
|
|
struct hvcs_partner_info *pi;
|
|
uint32_t unit_address = hvcsd->vdev->unit_address;
|
|
struct list_head head;
|
|
int retval;
|
|
|
|
spin_lock(&hvcs_pi_lock);
|
|
if (!hvcs_pi_buff) {
|
|
spin_unlock(&hvcs_pi_lock);
|
|
return -EFAULT;
|
|
}
|
|
retval = hvcs_get_partner_info(unit_address, &head, hvcs_pi_buff);
|
|
spin_unlock(&hvcs_pi_lock);
|
|
if (retval) {
|
|
printk(KERN_ERR "HVCS: Failed to fetch partner"
|
|
" info for vty-server@%x.\n", unit_address);
|
|
return retval;
|
|
}
|
|
|
|
/* nixes the values if the partner vty went away */
|
|
hvcsd->p_unit_address = 0;
|
|
hvcsd->p_partition_ID = 0;
|
|
|
|
list_for_each_entry(pi, &head, node)
|
|
hvcs_set_pi(pi, hvcsd);
|
|
|
|
hvcs_free_partner_info(&head);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* This function is executed by the driver "rescan" sysfs entry. It shouldn't
|
|
* be executed elsewhere, in order to prevent deadlock issues.
|
|
*/
|
|
static int hvcs_rescan_devices_list(void)
|
|
{
|
|
struct hvcs_struct *hvcsd;
|
|
unsigned long flags;
|
|
|
|
spin_lock(&hvcs_structs_lock);
|
|
|
|
list_for_each_entry(hvcsd, &hvcs_structs, next) {
|
|
spin_lock_irqsave(&hvcsd->lock, flags);
|
|
hvcs_get_pi(hvcsd);
|
|
spin_unlock_irqrestore(&hvcsd->lock, flags);
|
|
}
|
|
|
|
spin_unlock(&hvcs_structs_lock);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Farm this off into its own function because it could be more complex once
|
|
* multiple partners support is added. This function should be called with
|
|
* the hvcsd->lock held.
|
|
*/
|
|
static int hvcs_has_pi(struct hvcs_struct *hvcsd)
|
|
{
|
|
if ((!hvcsd->p_unit_address) || (!hvcsd->p_partition_ID))
|
|
return 0;
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* NOTE: It is possible that the super admin removed a partner vty and then
|
|
* added a different vty as the new partner.
|
|
*
|
|
* This function must be called with the hvcsd->lock held.
|
|
*/
|
|
static int hvcs_partner_connect(struct hvcs_struct *hvcsd)
|
|
{
|
|
int retval;
|
|
unsigned int unit_address = hvcsd->vdev->unit_address;
|
|
|
|
/*
|
|
* If there wasn't any pi when the device was added it doesn't meant
|
|
* there isn't any now. This driver isn't notified when a new partner
|
|
* vty is added to a vty-server so we discover changes on our own.
|
|
* Please see comments in hvcs_register_connection() for justification
|
|
* of this bizarre code.
|
|
*/
|
|
retval = hvcs_register_connection(unit_address,
|
|
hvcsd->p_partition_ID,
|
|
hvcsd->p_unit_address);
|
|
if (!retval) {
|
|
hvcsd->connected = 1;
|
|
return 0;
|
|
} else if (retval != -EINVAL)
|
|
return retval;
|
|
|
|
/*
|
|
* As per the spec re-get the pi and try again if -EINVAL after the
|
|
* first connection attempt.
|
|
*/
|
|
if (hvcs_get_pi(hvcsd))
|
|
return -ENOMEM;
|
|
|
|
if (!hvcs_has_pi(hvcsd))
|
|
return -ENODEV;
|
|
|
|
retval = hvcs_register_connection(unit_address,
|
|
hvcsd->p_partition_ID,
|
|
hvcsd->p_unit_address);
|
|
if (retval != -EINVAL) {
|
|
hvcsd->connected = 1;
|
|
return retval;
|
|
}
|
|
|
|
/*
|
|
* EBUSY is the most likely scenario though the vty could have been
|
|
* removed or there really could be an hcall error due to the parameter
|
|
* data but thanks to ambiguous firmware return codes we can't really
|
|
* tell.
|
|
*/
|
|
printk(KERN_INFO "HVCS: vty-server or partner"
|
|
" vty is busy. Try again later.\n");
|
|
return -EBUSY;
|
|
}
|
|
|
|
/* This function must be called with the hvcsd->lock held */
|
|
static void hvcs_partner_free(struct hvcs_struct *hvcsd)
|
|
{
|
|
int retval;
|
|
do {
|
|
retval = hvcs_free_connection(hvcsd->vdev->unit_address);
|
|
} while (retval == -EBUSY);
|
|
hvcsd->connected = 0;
|
|
}
|
|
|
|
/* This helper function must be called WITHOUT the hvcsd->lock held */
|
|
static int hvcs_enable_device(struct hvcs_struct *hvcsd, uint32_t unit_address,
|
|
unsigned int irq, struct vio_dev *vdev)
|
|
{
|
|
unsigned long flags;
|
|
int rc;
|
|
|
|
/*
|
|
* It is possible that the vty-server was removed between the time that
|
|
* the conn was registered and now.
|
|
*/
|
|
if (!(rc = request_irq(irq, &hvcs_handle_interrupt,
|
|
IRQF_DISABLED, "ibmhvcs", hvcsd))) {
|
|
/*
|
|
* It is possible the vty-server was removed after the irq was
|
|
* requested but before we have time to enable interrupts.
|
|
*/
|
|
if (vio_enable_interrupts(vdev) == H_SUCCESS)
|
|
return 0;
|
|
else {
|
|
printk(KERN_ERR "HVCS: int enable failed for"
|
|
" vty-server@%X.\n", unit_address);
|
|
free_irq(irq, hvcsd);
|
|
}
|
|
} else
|
|
printk(KERN_ERR "HVCS: irq req failed for"
|
|
" vty-server@%X.\n", unit_address);
|
|
|
|
spin_lock_irqsave(&hvcsd->lock, flags);
|
|
hvcs_partner_free(hvcsd);
|
|
spin_unlock_irqrestore(&hvcsd->lock, flags);
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
/*
|
|
* This always increments the 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 = NULL;
|
|
unsigned long flags;
|
|
|
|
spin_lock(&hvcs_structs_lock);
|
|
/* We can immediately discard OOB requests */
|
|
if (index >= 0 && index < HVCS_MAX_SERVER_ADAPTERS) {
|
|
list_for_each_entry(hvcsd, &hvcs_structs, next) {
|
|
spin_lock_irqsave(&hvcsd->lock, flags);
|
|
if (hvcsd->index == index) {
|
|
kref_get(&hvcsd->kref);
|
|
spin_unlock_irqrestore(&hvcsd->lock, flags);
|
|
spin_unlock(&hvcs_structs_lock);
|
|
return hvcsd;
|
|
}
|
|
spin_unlock_irqrestore(&hvcsd->lock, flags);
|
|
}
|
|
hvcsd = NULL;
|
|
}
|
|
|
|
spin_unlock(&hvcs_structs_lock);
|
|
return hvcsd;
|
|
}
|
|
|
|
/*
|
|
* This is invoked via the tty_open interface when a user app connects to the
|
|
* /dev node.
|
|
*/
|
|
static int hvcs_open(struct tty_struct *tty, struct file *filp)
|
|
{
|
|
struct hvcs_struct *hvcsd;
|
|
int rc, retval = 0;
|
|
unsigned long flags;
|
|
unsigned int irq;
|
|
struct vio_dev *vdev;
|
|
unsigned long unit_address;
|
|
|
|
if (tty->driver_data)
|
|
goto fast_open;
|
|
|
|
/*
|
|
* Is there a vty-server that shares the same index?
|
|
* This function increments the kref index.
|
|
*/
|
|
if (!(hvcsd = hvcs_get_by_index(tty->index))) {
|
|
printk(KERN_WARNING "HVCS: open failed, no device associated"
|
|
" with tty->index %d.\n", tty->index);
|
|
return -ENODEV;
|
|
}
|
|
|
|
spin_lock_irqsave(&hvcsd->lock, flags);
|
|
|
|
if (hvcsd->connected == 0)
|
|
if ((retval = hvcs_partner_connect(hvcsd)))
|
|
goto error_release;
|
|
|
|
hvcsd->open_count = 1;
|
|
hvcsd->tty = tty;
|
|
tty->driver_data = hvcsd;
|
|
|
|
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.
|
|
*/
|
|
if (((rc = hvcs_enable_device(hvcsd, unit_address, irq, vdev)))) {
|
|
kref_put(&hvcsd->kref, destroy_hvcs_struct);
|
|
printk(KERN_WARNING "HVCS: enable device failed.\n");
|
|
return rc;
|
|
}
|
|
|
|
goto open_success;
|
|
|
|
fast_open:
|
|
hvcsd = tty->driver_data;
|
|
|
|
spin_lock_irqsave(&hvcsd->lock, flags);
|
|
kref_get(&hvcsd->kref);
|
|
hvcsd->open_count++;
|
|
hvcsd->todo_mask |= HVCS_SCHED_READ;
|
|
spin_unlock_irqrestore(&hvcsd->lock, flags);
|
|
|
|
open_success:
|
|
hvcs_kick();
|
|
|
|
printk(KERN_INFO "HVCS: vty-server@%X connection opened.\n",
|
|
hvcsd->vdev->unit_address );
|
|
|
|
return 0;
|
|
|
|
error_release:
|
|
spin_unlock_irqrestore(&hvcsd->lock, flags);
|
|
kref_put(&hvcsd->kref, destroy_hvcs_struct);
|
|
|
|
printk(KERN_WARNING "HVCS: partner connect failed.\n");
|
|
return retval;
|
|
}
|
|
|
|
static void hvcs_close(struct tty_struct *tty, struct file *filp)
|
|
{
|
|
struct hvcs_struct *hvcsd;
|
|
unsigned long flags;
|
|
int irq = NO_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->open_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->tty = NULL;
|
|
|
|
irq = hvcsd->vdev->irq;
|
|
spin_unlock_irqrestore(&hvcsd->lock, flags);
|
|
|
|
tty_wait_until_sent(tty, HVCS_CLOSE_WAIT);
|
|
|
|
/*
|
|
* 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;
|
|
|
|
free_irq(irq, hvcsd);
|
|
kref_put(&hvcsd->kref, destroy_hvcs_struct);
|
|
return;
|
|
} else if (hvcsd->open_count < 0) {
|
|
printk(KERN_ERR "HVCS: vty-server@%X open_count: %d"
|
|
" is missmanaged.\n",
|
|
hvcsd->vdev->unit_address, hvcsd->open_count);
|
|
}
|
|
|
|
spin_unlock_irqrestore(&hvcsd->lock, flags);
|
|
kref_put(&hvcsd->kref, destroy_hvcs_struct);
|
|
}
|
|
|
|
static void hvcs_hangup(struct tty_struct * tty)
|
|
{
|
|
struct hvcs_struct *hvcsd = tty->driver_data;
|
|
unsigned long flags;
|
|
int temp_open_count;
|
|
int irq = NO_IRQ;
|
|
|
|
spin_lock_irqsave(&hvcsd->lock, flags);
|
|
/* Preserve this so that we know how many kref refs to put */
|
|
temp_open_count = hvcsd->open_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 */
|
|
hvcsd->tty->driver_data = NULL;
|
|
hvcsd->tty = NULL;
|
|
|
|
hvcsd->open_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.
|
|
*/
|
|
kref_put(&hvcsd->kref, destroy_hvcs_struct);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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 succedded 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->open_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 guarentee 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->open_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 = {
|
|
.open = hvcs_open,
|
|
.close = hvcs_close,
|
|
.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(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 __init hvcs_module_init(void)
|
|
{
|
|
int rc;
|
|
int num_ttys_to_alloc;
|
|
|
|
printk(KERN_INFO "Initializing %s\n", hvcs_driver_string);
|
|
|
|
/* 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)
|
|
return -ENOMEM;
|
|
|
|
if (hvcs_alloc_index_list(num_ttys_to_alloc)) {
|
|
rc = -ENOMEM;
|
|
goto index_fail;
|
|
}
|
|
|
|
hvcs_tty_driver->owner = THIS_MODULE;
|
|
|
|
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 = kmalloc(PAGE_SIZE, 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. Driver not loaded.\n");
|
|
rc = -EIO;
|
|
goto kthread_fail;
|
|
}
|
|
|
|
rc = vio_register_driver(&hvcs_vio_driver);
|
|
if (rc) {
|
|
printk(KERN_ERR "HVCS: can't register vio driver\n");
|
|
goto vio_fail;
|
|
}
|
|
|
|
/*
|
|
* 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) {
|
|
printk(KERN_ERR "HVCS: sysfs attr create failed\n");
|
|
goto attr_fail;
|
|
}
|
|
|
|
printk(KERN_INFO "HVCS: driver module inserted.\n");
|
|
|
|
return 0;
|
|
|
|
attr_fail:
|
|
vio_unregister_driver(&hvcs_vio_driver);
|
|
vio_fail:
|
|
kthread_stop(hvcs_task);
|
|
kthread_fail:
|
|
kfree(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;
|
|
return rc;
|
|
}
|
|
|
|
static void __exit hvcs_module_exit(void)
|
|
{
|
|
/*
|
|
* This driver receives hvcs_remove callbacks for each device upon
|
|
* module removal.
|
|
*/
|
|
|
|
/*
|
|
* 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);
|
|
kfree(hvcs_pi_buff);
|
|
hvcs_pi_buff = NULL;
|
|
spin_unlock(&hvcs_pi_lock);
|
|
|
|
driver_remove_file(&hvcs_vio_driver.driver, &driver_attr_rescan);
|
|
|
|
vio_unregister_driver(&hvcs_vio_driver);
|
|
|
|
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);
|