// SPDX-License-Identifier: GPL-2.0-only
/*
* Generic gameport layer
*
* Copyright (c) 1999-2002 Vojtech Pavlik
* Copyright (c) 2005 Dmitry Torokhov
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/stddef.h>
#include <linux/module.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/gameport.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/workqueue.h>
#include <linux/sched.h> /* HZ */
#include <linux/mutex.h>
#include <linux/timekeeping.h>
/*#include <asm/io.h>*/
MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
MODULE_DESCRIPTION("Generic gameport layer");
MODULE_LICENSE("GPL");
static bool use_ktime = true;
module_param(use_ktime, bool, 0400);
MODULE_PARM_DESC(use_ktime, "Use ktime for measuring I/O speed");
/*
* gameport_mutex protects entire gameport subsystem and is taken
* every time gameport port or driver registrered or unregistered.
*/
static DEFINE_MUTEX(gameport_mutex);
static LIST_HEAD(gameport_list);
static struct bus_type gameport_bus;
static void gameport_add_port(struct gameport *gameport);
static void gameport_attach_driver(struct gameport_driver *drv);
static void gameport_reconnect_port(struct gameport *gameport);
static void gameport_disconnect_port(struct gameport *gameport);
#if defined(__i386__)
#include <linux/i8253.h>
#define DELTA(x,y) ((y)-(x)+((y)<(x)?1193182/HZ:0))
#define GET_TIME(x) do { x = get_time_pit(); } while (0)
static unsigned int get_time_pit(void)
{
unsigned long flags;
unsigned int count;
raw_spin_lock_irqsave(&i8253_lock, flags);
outb_p(0x00, 0x43);
count = inb_p(0x40);
count |= inb_p(0x40) << 8;
raw_spin_unlock_irqrestore(&i8253_lock, flags);
return count;
}
#endif
/*
* gameport_measure_speed() measures the gameport i/o speed.
*/
static int gameport_measure_speed(struct gameport *gameport)
{
unsigned int i, t, tx;
u64 t1, t2, t3;
unsigned long flags;
if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
return 0;
tx = ~0;
for (i = 0; i < 50; i++) {
local_irq_save(flags);
t1 = ktime_get_ns();
for (t = 0; t < 50; t++)
gameport_read(gameport);
t2 = ktime_get_ns();
t3 = ktime_get_ns();
local_irq_restore(flags);
udelay(i * 10);
t = (t2 - t1) - (t3 - t2);
if (t < tx)
tx = t;
}
gameport_close(gameport);
t = 1000000 * 50;
if (tx)
t /= tx;
return t;
}
static int old_gameport_measure_speed(struct gameport *gameport)
{
#if defined(__i386__)
unsigned int i, t, t1, t2, t3, tx;
unsigned long flags;
if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
return 0;
tx = 1 << 30;
for(i = 0; i < 50; i++) {
local_irq_save(flags);
GET_TIME(t1);
for (t = 0; t < 50; t++) gameport_read(gameport);
GET_TIME(t2);
GET_TIME(t3);
local_irq_restore(flags);
udelay(i * 10);
if ((t = DELTA(t2,t1) - DELTA(t3,t2)) < tx) tx = t;
}
gameport_close(gameport);
return 59659 / (tx < 1 ? 1 : tx);
#elif defined (__x86_64__)
unsigned int i, t;
unsigned long tx, t1, t2, flags;
if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
return 0;
tx = 1 << 30;
for(i = 0; i < 50; i++) {
local_irq_save(flags);
t1 = rdtsc();
for (t = 0; t < 50; t++) gameport_read(gameport);
t2 = rdtsc();
local_irq_restore(flags);
udelay(i * 10);
if (t2 - t1 < tx) tx = t2 - t1;
}
gameport_close(gameport);
return (this_cpu_read(cpu_info.loops_per_jiffy) *
(unsigned long)HZ / (1000 / 50)) / (tx < 1 ? 1 : tx);
#else
unsigned int j, t = 0;
if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
return 0;
j = jiffies; while (j == jiffies);
j = jiffies; while (j == jiffies) { t++; gameport_read(gameport); }
gameport_close(gameport);
return t * HZ / 1000;
#endif
}
void gameport_start_polling(struct