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kernel-ark/drivers/input/mouse/pc110pad.c
David Howells 7d12e780e0 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 15:10:12 +01:00

171 lines
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C
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/*
* $Id: pc110pad.c,v 1.12 2001/09/25 10:12:07 vojtech Exp $
*
* Copyright (c) 2000-2001 Vojtech Pavlik
*
* Based on the work of:
* Alan Cox Robin O'Leary
*/
/*
* IBM PC110 touchpad driver for Linux
*/
/*
* 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/kernel.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/input.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/pci.h>
#include <asm/io.h>
#include <asm/irq.h>
MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
MODULE_DESCRIPTION("IBM PC110 touchpad driver");
MODULE_LICENSE("GPL");
#define PC110PAD_OFF 0x30
#define PC110PAD_ON 0x38
static int pc110pad_irq = 10;
static int pc110pad_io = 0x15e0;
static struct input_dev *pc110pad_dev;
static int pc110pad_data[3];
static int pc110pad_count;
static irqreturn_t pc110pad_interrupt(int irq, void *ptr)
{
int value = inb_p(pc110pad_io);
int handshake = inb_p(pc110pad_io + 2);
outb_p(handshake | 1, pc110pad_io + 2);
outb_p(handshake & ~1, pc110pad_io + 2);
inb_p(0x64);
pc110pad_data[pc110pad_count++] = value;
if (pc110pad_count < 3)
return IRQ_HANDLED;
input_report_key(pc110pad_dev, BTN_TOUCH,
pc110pad_data[0] & 0x01);
input_report_abs(pc110pad_dev, ABS_X,
pc110pad_data[1] | ((pc110pad_data[0] << 3) & 0x80) | ((pc110pad_data[0] << 1) & 0x100));
input_report_abs(pc110pad_dev, ABS_Y,
pc110pad_data[2] | ((pc110pad_data[0] << 4) & 0x80));
input_sync(pc110pad_dev);
pc110pad_count = 0;
return IRQ_HANDLED;
}
static void pc110pad_close(struct input_dev *dev)
{
outb(PC110PAD_OFF, pc110pad_io + 2);
}
static int pc110pad_open(struct input_dev *dev)
{
pc110pad_interrupt(0, NULL);
pc110pad_interrupt(0, NULL);
pc110pad_interrupt(0, NULL);
outb(PC110PAD_ON, pc110pad_io + 2);
pc110pad_count = 0;
return 0;
}
/*
* We try to avoid enabling the hardware if it's not
* there, but we don't know how to test. But we do know
* that the PC110 is not a PCI system. So if we find any
* PCI devices in the machine, we don't have a PC110.
*/
static int __init pc110pad_init(void)
{
struct pci_dev *dev;
dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, NULL);
if (dev) {
pci_dev_put(dev);
return -ENOENT;
}
if (!request_region(pc110pad_io, 4, "pc110pad")) {
printk(KERN_ERR "pc110pad: I/O area %#x-%#x in use.\n",
pc110pad_io, pc110pad_io + 4);
return -EBUSY;
}
outb(PC110PAD_OFF, pc110pad_io + 2);
if (request_irq(pc110pad_irq, pc110pad_interrupt, 0, "pc110pad", NULL)) {
release_region(pc110pad_io, 4);
printk(KERN_ERR "pc110pad: Unable to get irq %d.\n", pc110pad_irq);
return -EBUSY;
}
if (!(pc110pad_dev = input_allocate_device())) {
free_irq(pc110pad_irq, NULL);
release_region(pc110pad_io, 4);
printk(KERN_ERR "pc110pad: Not enough memory.\n");
return -ENOMEM;
}
pc110pad_dev->name = "IBM PC110 TouchPad";
pc110pad_dev->phys = "isa15e0/input0";
pc110pad_dev->id.bustype = BUS_ISA;
pc110pad_dev->id.vendor = 0x0003;
pc110pad_dev->id.product = 0x0001;
pc110pad_dev->id.version = 0x0100;
pc110pad_dev->evbit[0] = BIT(EV_KEY) | BIT(EV_ABS);
pc110pad_dev->absbit[0] = BIT(ABS_X) | BIT(ABS_Y);
pc110pad_dev->keybit[LONG(BTN_TOUCH)] = BIT(BTN_TOUCH);
pc110pad_dev->absmax[ABS_X] = 0x1ff;
pc110pad_dev->absmax[ABS_Y] = 0x0ff;
pc110pad_dev->open = pc110pad_open;
pc110pad_dev->close = pc110pad_close;
input_register_device(pc110pad_dev);
return 0;
}
static void __exit pc110pad_exit(void)
{
outb(PC110PAD_OFF, pc110pad_io + 2);
free_irq(pc110pad_irq, NULL);
input_unregister_device(pc110pad_dev);
release_region(pc110pad_io, 4);
}
module_init(pc110pad_init);
module_exit(pc110pad_exit);
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