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![David Howells](/assets/img/avatar_default.png)
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)
234 lines
5.1 KiB
C
234 lines
5.1 KiB
C
/*
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* linux/drivers/input/serio/pcips2.c
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*
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* Copyright (C) 2003 Russell King, All Rights Reserved.
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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.
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*
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* I'm not sure if this is a generic PS/2 PCI interface or specific to
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* the Mobility Electronics docking station.
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*/
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#include <linux/module.h>
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#include <linux/interrupt.h>
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#include <linux/ioport.h>
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#include <linux/input.h>
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#include <linux/pci.h>
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#include <linux/init.h>
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#include <linux/serio.h>
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#include <linux/delay.h>
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#include <asm/io.h>
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#define PS2_CTRL (0)
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#define PS2_STATUS (1)
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#define PS2_DATA (2)
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#define PS2_CTRL_CLK (1<<0)
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#define PS2_CTRL_DAT (1<<1)
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#define PS2_CTRL_TXIRQ (1<<2)
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#define PS2_CTRL_ENABLE (1<<3)
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#define PS2_CTRL_RXIRQ (1<<4)
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#define PS2_STAT_CLK (1<<0)
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#define PS2_STAT_DAT (1<<1)
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#define PS2_STAT_PARITY (1<<2)
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#define PS2_STAT_RXFULL (1<<5)
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#define PS2_STAT_TXBUSY (1<<6)
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#define PS2_STAT_TXEMPTY (1<<7)
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struct pcips2_data {
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struct serio *io;
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unsigned int base;
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struct pci_dev *dev;
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};
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static int pcips2_write(struct serio *io, unsigned char val)
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{
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struct pcips2_data *ps2if = io->port_data;
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unsigned int stat;
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do {
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stat = inb(ps2if->base + PS2_STATUS);
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cpu_relax();
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} while (!(stat & PS2_STAT_TXEMPTY));
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outb(val, ps2if->base + PS2_DATA);
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return 0;
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}
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static irqreturn_t pcips2_interrupt(int irq, void *devid)
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{
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struct pcips2_data *ps2if = devid;
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unsigned char status, scancode;
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int handled = 0;
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do {
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unsigned int flag;
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status = inb(ps2if->base + PS2_STATUS);
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if (!(status & PS2_STAT_RXFULL))
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break;
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handled = 1;
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scancode = inb(ps2if->base + PS2_DATA);
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if (status == 0xff && scancode == 0xff)
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break;
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flag = (status & PS2_STAT_PARITY) ? 0 : SERIO_PARITY;
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if (hweight8(scancode) & 1)
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flag ^= SERIO_PARITY;
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serio_interrupt(ps2if->io, scancode, flag);
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} while (1);
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return IRQ_RETVAL(handled);
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}
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static void pcips2_flush_input(struct pcips2_data *ps2if)
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{
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unsigned char status, scancode;
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do {
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status = inb(ps2if->base + PS2_STATUS);
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if (!(status & PS2_STAT_RXFULL))
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break;
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scancode = inb(ps2if->base + PS2_DATA);
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if (status == 0xff && scancode == 0xff)
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break;
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} while (1);
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}
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static int pcips2_open(struct serio *io)
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{
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struct pcips2_data *ps2if = io->port_data;
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int ret, val = 0;
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outb(PS2_CTRL_ENABLE, ps2if->base);
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pcips2_flush_input(ps2if);
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ret = request_irq(ps2if->dev->irq, pcips2_interrupt, IRQF_SHARED,
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"pcips2", ps2if);
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if (ret == 0)
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val = PS2_CTRL_ENABLE | PS2_CTRL_RXIRQ;
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outb(val, ps2if->base);
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return ret;
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}
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static void pcips2_close(struct serio *io)
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{
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struct pcips2_data *ps2if = io->port_data;
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outb(0, ps2if->base);
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free_irq(ps2if->dev->irq, ps2if);
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}
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static int __devinit pcips2_probe(struct pci_dev *dev, const struct pci_device_id *id)
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{
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struct pcips2_data *ps2if;
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struct serio *serio;
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int ret;
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ret = pci_enable_device(dev);
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if (ret)
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goto out;
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ret = pci_request_regions(dev, "pcips2");
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if (ret)
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goto disable;
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ps2if = kmalloc(sizeof(struct pcips2_data), GFP_KERNEL);
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serio = kmalloc(sizeof(struct serio), GFP_KERNEL);
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if (!ps2if || !serio) {
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ret = -ENOMEM;
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goto release;
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}
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memset(ps2if, 0, sizeof(struct pcips2_data));
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memset(serio, 0, sizeof(struct serio));
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serio->id.type = SERIO_8042;
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serio->write = pcips2_write;
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serio->open = pcips2_open;
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serio->close = pcips2_close;
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strlcpy(serio->name, pci_name(dev), sizeof(serio->name));
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strlcpy(serio->phys, dev->dev.bus_id, sizeof(serio->phys));
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serio->port_data = ps2if;
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serio->dev.parent = &dev->dev;
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ps2if->io = serio;
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ps2if->dev = dev;
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ps2if->base = pci_resource_start(dev, 0);
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pci_set_drvdata(dev, ps2if);
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serio_register_port(ps2if->io);
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return 0;
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release:
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kfree(ps2if);
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kfree(serio);
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pci_release_regions(dev);
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disable:
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pci_disable_device(dev);
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out:
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return ret;
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}
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static void __devexit pcips2_remove(struct pci_dev *dev)
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{
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struct pcips2_data *ps2if = pci_get_drvdata(dev);
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serio_unregister_port(ps2if->io);
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pci_set_drvdata(dev, NULL);
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kfree(ps2if);
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pci_release_regions(dev);
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pci_disable_device(dev);
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}
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static struct pci_device_id pcips2_ids[] = {
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{
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.vendor = 0x14f2, /* MOBILITY */
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.device = 0x0123, /* Keyboard */
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.subvendor = PCI_ANY_ID,
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.subdevice = PCI_ANY_ID,
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.class = PCI_CLASS_INPUT_KEYBOARD << 8,
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.class_mask = 0xffff00,
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},
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{
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.vendor = 0x14f2, /* MOBILITY */
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.device = 0x0124, /* Mouse */
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.subvendor = PCI_ANY_ID,
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.subdevice = PCI_ANY_ID,
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.class = PCI_CLASS_INPUT_MOUSE << 8,
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.class_mask = 0xffff00,
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},
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{ 0, }
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};
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static struct pci_driver pcips2_driver = {
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.name = "pcips2",
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.id_table = pcips2_ids,
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.probe = pcips2_probe,
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.remove = __devexit_p(pcips2_remove),
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};
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static int __init pcips2_init(void)
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{
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return pci_register_driver(&pcips2_driver);
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}
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static void __exit pcips2_exit(void)
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{
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pci_unregister_driver(&pcips2_driver);
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}
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module_init(pcips2_init);
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module_exit(pcips2_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>");
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MODULE_DESCRIPTION("PCI PS/2 keyboard/mouse driver");
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MODULE_DEVICE_TABLE(pci, pcips2_ids);
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