alistair23-linux/include/linux/serio.h
Dmitry Torokhov 4097461897 Input: i8042 - break load dependency between atkbd/psmouse and i8042
As explained in 1407814240-4275-1-git-send-email-decui@microsoft.com we
have a hard load dependency between i8042 and atkbd which prevents
keyboard from working on Gen2 Hyper-V VMs.

> hyperv_keyboard invokes serio_interrupt(), which needs a valid serio
> driver like atkbd.c.  atkbd.c depends on libps2.c because it invokes
> ps2_command().  libps2.c depends on i8042.c because it invokes
> i8042_check_port_owner().  As a result, hyperv_keyboard actually
> depends on i8042.c.
>
> For a Generation 2 Hyper-V VM (meaning no i8042 device emulated), if a
> Linux VM (like Arch Linux) happens to configure CONFIG_SERIO_I8042=m
> rather than =y, atkbd.ko can't load because i8042.ko can't load(due to
> no i8042 device emulated) and finally hyperv_keyboard can't work and
> the user can't input: https://bugs.archlinux.org/task/39820
> (Ubuntu/RHEL/SUSE aren't affected since they use CONFIG_SERIO_I8042=y)

To break the dependency we move away from using i8042_check_port_owner()
and instead allow serio port owner specify a mutex that clients should use
to serialize PS/2 command stream.

Reported-by: Mark Laws <mdl@60hz.org>
Tested-by: Mark Laws <mdl@60hz.org>
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
2016-07-27 14:20:09 -07:00

167 lines
4.4 KiB
C

/*
* Copyright (C) 1999-2002 Vojtech Pavlik
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*/
#ifndef _SERIO_H
#define _SERIO_H
#include <linux/types.h>
#include <linux/interrupt.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/mutex.h>
#include <linux/device.h>
#include <linux/mod_devicetable.h>
#include <uapi/linux/serio.h>
extern struct bus_type serio_bus;
struct serio {
void *port_data;
char name[32];
char phys[32];
char firmware_id[128];
bool manual_bind;
struct serio_device_id id;
/* Protects critical sections from port's interrupt handler */
spinlock_t lock;
int (*write)(struct serio *, unsigned char);
int (*open)(struct serio *);
void (*close)(struct serio *);
int (*start)(struct serio *);
void (*stop)(struct serio *);
struct serio *parent;
/* Entry in parent->children list */
struct list_head child_node;
struct list_head children;
/* Level of nesting in serio hierarchy */
unsigned int depth;
/*
* serio->drv is accessed from interrupt handlers; when modifying
* caller should acquire serio->drv_mutex and serio->lock.
*/
struct serio_driver *drv;
/* Protects serio->drv so attributes can pin current driver */
struct mutex drv_mutex;
struct device dev;
struct list_head node;
/*
* For use by PS/2 layer when several ports share hardware and
* may get indigestion when exposed to concurrent access (i8042).
*/
struct mutex *ps2_cmd_mutex;
};
#define to_serio_port(d) container_of(d, struct serio, dev)
struct serio_driver {
const char *description;
const struct serio_device_id *id_table;
bool manual_bind;
void (*write_wakeup)(struct serio *);
irqreturn_t (*interrupt)(struct serio *, unsigned char, unsigned int);
int (*connect)(struct serio *, struct serio_driver *drv);
int (*reconnect)(struct serio *);
void (*disconnect)(struct serio *);
void (*cleanup)(struct serio *);
struct device_driver driver;
};
#define to_serio_driver(d) container_of(d, struct serio_driver, driver)
int serio_open(struct serio *serio, struct serio_driver *drv);
void serio_close(struct serio *serio);
void serio_rescan(struct serio *serio);
void serio_reconnect(struct serio *serio);
irqreturn_t serio_interrupt(struct serio *serio, unsigned char data, unsigned int flags);
void __serio_register_port(struct serio *serio, struct module *owner);
/* use a define to avoid include chaining to get THIS_MODULE */
#define serio_register_port(serio) \
__serio_register_port(serio, THIS_MODULE)
void serio_unregister_port(struct serio *serio);
void serio_unregister_child_port(struct serio *serio);
int __must_check __serio_register_driver(struct serio_driver *drv,
struct module *owner, const char *mod_name);
/* use a define to avoid include chaining to get THIS_MODULE & friends */
#define serio_register_driver(drv) \
__serio_register_driver(drv, THIS_MODULE, KBUILD_MODNAME)
void serio_unregister_driver(struct serio_driver *drv);
/**
* module_serio_driver() - Helper macro for registering a serio driver
* @__serio_driver: serio_driver struct
*
* Helper macro for serio drivers which do not do anything special in
* module init/exit. This eliminates a lot of boilerplate. Each module
* may only use this macro once, and calling it replaces module_init()
* and module_exit().
*/
#define module_serio_driver(__serio_driver) \
module_driver(__serio_driver, serio_register_driver, \
serio_unregister_driver)
static inline int serio_write(struct serio *serio, unsigned char data)
{
if (serio->write)
return serio->write(serio, data);
else
return -1;
}
static inline void serio_drv_write_wakeup(struct serio *serio)
{
if (serio->drv && serio->drv->write_wakeup)
serio->drv->write_wakeup(serio);
}
/*
* Use the following functions to manipulate serio's per-port
* driver-specific data.
*/
static inline void *serio_get_drvdata(struct serio *serio)
{
return dev_get_drvdata(&serio->dev);
}
static inline void serio_set_drvdata(struct serio *serio, void *data)
{
dev_set_drvdata(&serio->dev, data);
}
/*
* Use the following functions to protect critical sections in
* driver code from port's interrupt handler
*/
static inline void serio_pause_rx(struct serio *serio)
{
spin_lock_irq(&serio->lock);
}
static inline void serio_continue_rx(struct serio *serio)
{
spin_unlock_irq(&serio->lock);
}
#endif