linux/drivers/input/serio/q40kbd.c

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/*
* Copyright (c) 2000-2001 Vojtech Pavlik
*
* Based on the work of:
* Richard Zidlicky <Richard.Zidlicky@stud.informatik.uni-erlangen.de>
*/
/*
* Q40 PS/2 keyboard controller driver for Linux/m68k
*/
/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Should you need to contact me, the author, you can do so either by
* e-mail - mail your message to <vojtech@ucw.cz>, or by paper mail:
* Vojtech Pavlik, Simunkova 1594, Prague 8, 182 00 Czech Republic
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/serio.h>
#include <linux/interrupt.h>
#include <linux/err.h>
#include <linux/bitops.h>
#include <linux/platform_device.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/q40_master.h>
#include <asm/irq.h>
#include <asm/q40ints.h>
MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
MODULE_DESCRIPTION("Q40 PS/2 keyboard controller driver");
MODULE_LICENSE("GPL");
static DEFINE_SPINLOCK(q40kbd_lock);
static struct serio *q40kbd_port;
static struct platform_device *q40kbd_device;
IRQ: Maintain regs pointer globally rather than passing to IRQ handlers Maintain a per-CPU global "struct pt_regs *" variable which can be used instead of passing regs around manually through all ~1800 interrupt handlers in the Linux kernel. The regs pointer is used in few places, but it potentially costs both stack space and code to pass it around. On the FRV arch, removing the regs parameter from all the genirq function results in a 20% speed up of the IRQ exit path (ie: from leaving timer_interrupt() to leaving do_IRQ()). Where appropriate, an arch may override the generic storage facility and do something different with the variable. On FRV, for instance, the address is maintained in GR28 at all times inside the kernel as part of general exception handling. Having looked over the code, it appears that the parameter may be handed down through up to twenty or so layers of functions. Consider a USB character device attached to a USB hub, attached to a USB controller that posts its interrupts through a cascaded auxiliary interrupt controller. A character device driver may want to pass regs to the sysrq handler through the input layer which adds another few layers of parameter passing. I've build this code with allyesconfig for x86_64 and i386. I've runtested the main part of the code on FRV and i386, though I can't test most of the drivers. I've also done partial conversion for powerpc and MIPS - these at least compile with minimal configurations. This will affect all archs. Mostly the changes should be relatively easy. Take do_IRQ(), store the regs pointer at the beginning, saving the old one: struct pt_regs *old_regs = set_irq_regs(regs); And put the old one back at the end: set_irq_regs(old_regs); Don't pass regs through to generic_handle_irq() or __do_IRQ(). In timer_interrupt(), this sort of change will be necessary: - update_process_times(user_mode(regs)); - profile_tick(CPU_PROFILING, regs); + update_process_times(user_mode(get_irq_regs())); + profile_tick(CPU_PROFILING); I'd like to move update_process_times()'s use of get_irq_regs() into itself, except that i386, alone of the archs, uses something other than user_mode(). Some notes on the interrupt handling in the drivers: (*) input_dev() is now gone entirely. The regs pointer is no longer stored in the input_dev struct. (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does something different depending on whether it's been supplied with a regs pointer or not. (*) Various IRQ handler function pointers have been moved to type irq_handler_t. Signed-Off-By: David Howells <dhowells@redhat.com> (cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-05 13:55:46 +00:00
static irqreturn_t q40kbd_interrupt(int irq, void *dev_id)
{
unsigned long flags;
spin_lock_irqsave(&q40kbd_lock, flags);
if (Q40_IRQ_KEYB_MASK & master_inb(INTERRUPT_REG))
IRQ: Maintain regs pointer globally rather than passing to IRQ handlers Maintain a per-CPU global "struct pt_regs *" variable which can be used instead of passing regs around manually through all ~1800 interrupt handlers in the Linux kernel. The regs pointer is used in few places, but it potentially costs both stack space and code to pass it around. On the FRV arch, removing the regs parameter from all the genirq function results in a 20% speed up of the IRQ exit path (ie: from leaving timer_interrupt() to leaving do_IRQ()). Where appropriate, an arch may override the generic storage facility and do something different with the variable. On FRV, for instance, the address is maintained in GR28 at all times inside the kernel as part of general exception handling. Having looked over the code, it appears that the parameter may be handed down through up to twenty or so layers of functions. Consider a USB character device attached to a USB hub, attached to a USB controller that posts its interrupts through a cascaded auxiliary interrupt controller. A character device driver may want to pass regs to the sysrq handler through the input layer which adds another few layers of parameter passing. I've build this code with allyesconfig for x86_64 and i386. I've runtested the main part of the code on FRV and i386, though I can't test most of the drivers. I've also done partial conversion for powerpc and MIPS - these at least compile with minimal configurations. This will affect all archs. Mostly the changes should be relatively easy. Take do_IRQ(), store the regs pointer at the beginning, saving the old one: struct pt_regs *old_regs = set_irq_regs(regs); And put the old one back at the end: set_irq_regs(old_regs); Don't pass regs through to generic_handle_irq() or __do_IRQ(). In timer_interrupt(), this sort of change will be necessary: - update_process_times(user_mode(regs)); - profile_tick(CPU_PROFILING, regs); + update_process_times(user_mode(get_irq_regs())); + profile_tick(CPU_PROFILING); I'd like to move update_process_times()'s use of get_irq_regs() into itself, except that i386, alone of the archs, uses something other than user_mode(). Some notes on the interrupt handling in the drivers: (*) input_dev() is now gone entirely. The regs pointer is no longer stored in the input_dev struct. (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does something different depending on whether it's been supplied with a regs pointer or not. (*) Various IRQ handler function pointers have been moved to type irq_handler_t. Signed-Off-By: David Howells <dhowells@redhat.com> (cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-05 13:55:46 +00:00
serio_interrupt(q40kbd_port, master_inb(KEYCODE_REG), 0);
master_outb(-1, KEYBOARD_UNLOCK_REG);
spin_unlock_irqrestore(&q40kbd_lock, flags);
return IRQ_HANDLED;
}
/*
* q40kbd_flush() flushes all data that may be in the keyboard buffers
*/
static void q40kbd_flush(void)
{
int maxread = 100;
unsigned long flags;
spin_lock_irqsave(&q40kbd_lock, flags);
while (maxread-- && (Q40_IRQ_KEYB_MASK & master_inb(INTERRUPT_REG)))
master_inb(KEYCODE_REG);
spin_unlock_irqrestore(&q40kbd_lock, flags);
}
/*
* q40kbd_open() is called when a port is open by the higher layer.
* It allocates the interrupt and enables in in the chip.
*/
static int q40kbd_open(struct serio *port)
{
q40kbd_flush();
if (request_irq(Q40_IRQ_KEYBOARD, q40kbd_interrupt, 0, "q40kbd", NULL)) {
printk(KERN_ERR "q40kbd.c: Can't get irq %d.\n", Q40_IRQ_KEYBOARD);
return -EBUSY;
}
/* off we go */
master_outb(-1, KEYBOARD_UNLOCK_REG);
master_outb(1, KEY_IRQ_ENABLE_REG);
return 0;
}
static void q40kbd_close(struct serio *port)
{
master_outb(0, KEY_IRQ_ENABLE_REG);
master_outb(-1, KEYBOARD_UNLOCK_REG);
free_irq(Q40_IRQ_KEYBOARD, NULL);
q40kbd_flush();
}
static int __devinit q40kbd_probe(struct platform_device *dev)
{
q40kbd_port = kzalloc(sizeof(struct serio), GFP_KERNEL);
if (!q40kbd_port)
return -ENOMEM;
q40kbd_port->id.type = SERIO_8042;
q40kbd_port->open = q40kbd_open;
q40kbd_port->close = q40kbd_close;
q40kbd_port->dev.parent = &dev->dev;
strlcpy(q40kbd_port->name, "Q40 Kbd Port", sizeof(q40kbd_port->name));
strlcpy(q40kbd_port->phys, "Q40", sizeof(q40kbd_port->phys));
serio_register_port(q40kbd_port);
printk(KERN_INFO "serio: Q40 kbd registered\n");
return 0;
}
static int __devexit q40kbd_remove(struct platform_device *dev)
{
serio_unregister_port(q40kbd_port);
return 0;
}
static struct platform_driver q40kbd_driver = {
.driver = {
.name = "q40kbd",
.owner = THIS_MODULE,
},
.probe = q40kbd_probe,
.remove = __devexit_p(q40kbd_remove),
};
static int __init q40kbd_init(void)
{
int error;
if (!MACH_IS_Q40)
return -ENODEV;
error = platform_driver_register(&q40kbd_driver);
if (error)
return error;
q40kbd_device = platform_device_alloc("q40kbd", -1);
if (!q40kbd_device)
goto err_unregister_driver;
error = platform_device_add(q40kbd_device);
if (error)
goto err_free_device;
return 0;
err_free_device:
platform_device_put(q40kbd_device);
err_unregister_driver:
platform_driver_unregister(&q40kbd_driver);
return error;
}
static void __exit q40kbd_exit(void)
{
platform_device_unregister(q40kbd_device);
platform_driver_unregister(&q40kbd_driver);
}
module_init(q40kbd_init);
module_exit(q40kbd_exit);