![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)
256 lines
6.6 KiB
C
256 lines
6.6 KiB
C
/*
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* $Id: spaceorb.c,v 1.15 2002/01/22 20:29:19 vojtech Exp $
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*
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* Copyright (c) 1999-2001 Vojtech Pavlik
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*
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* Based on the work of:
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* David Thompson
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*/
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/*
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* SpaceTec SpaceOrb 360 and Avenger 6dof controller driver for Linux
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*/
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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, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* Should you need to contact me, the author, you can do so either by
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* e-mail - mail your message to <vojtech@ucw.cz>, or by paper mail:
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* Vojtech Pavlik, Simunkova 1594, Prague 8, 182 00 Czech Republic
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*/
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/input.h>
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#include <linux/serio.h>
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#define DRIVER_DESC "SpaceTec SpaceOrb 360 and Avenger 6dof controller driver"
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MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
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MODULE_DESCRIPTION(DRIVER_DESC);
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MODULE_LICENSE("GPL");
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/*
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* Constants.
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*/
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#define SPACEORB_MAX_LENGTH 64
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static int spaceorb_buttons[] = { BTN_TL, BTN_TR, BTN_Y, BTN_X, BTN_B, BTN_A };
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static int spaceorb_axes[] = { ABS_X, ABS_Y, ABS_Z, ABS_RX, ABS_RY, ABS_RZ };
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/*
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* Per-Orb data.
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*/
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struct spaceorb {
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struct input_dev *dev;
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int idx;
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unsigned char data[SPACEORB_MAX_LENGTH];
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char phys[32];
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};
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static unsigned char spaceorb_xor[] = "SpaceWare";
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static unsigned char *spaceorb_errors[] = { "EEPROM storing 0 failed", "Receive queue overflow", "Transmit queue timeout",
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"Bad packet", "Power brown-out", "EEPROM checksum error", "Hardware fault" };
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/*
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* spaceorb_process_packet() decodes packets the driver receives from the
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* SpaceOrb.
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*/
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static void spaceorb_process_packet(struct spaceorb *spaceorb)
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{
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struct input_dev *dev = spaceorb->dev;
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unsigned char *data = spaceorb->data;
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unsigned char c = 0;
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int axes[6];
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int i;
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if (spaceorb->idx < 2) return;
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for (i = 0; i < spaceorb->idx; i++) c ^= data[i];
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if (c) return;
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switch (data[0]) {
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case 'R': /* Reset packet */
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spaceorb->data[spaceorb->idx - 1] = 0;
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for (i = 1; i < spaceorb->idx && spaceorb->data[i] == ' '; i++);
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printk(KERN_INFO "input: %s [%s] is %s\n",
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dev->name, spaceorb->data + i, spaceorb->phys);
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break;
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case 'D': /* Ball + button data */
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if (spaceorb->idx != 12) return;
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for (i = 0; i < 9; i++) spaceorb->data[i+2] ^= spaceorb_xor[i];
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axes[0] = ( data[2] << 3) | (data[ 3] >> 4);
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axes[1] = ((data[3] & 0x0f) << 6) | (data[ 4] >> 1);
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axes[2] = ((data[4] & 0x01) << 9) | (data[ 5] << 2) | (data[4] >> 5);
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axes[3] = ((data[6] & 0x1f) << 5) | (data[ 7] >> 2);
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axes[4] = ((data[7] & 0x03) << 8) | (data[ 8] << 1) | (data[7] >> 6);
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axes[5] = ((data[9] & 0x3f) << 4) | (data[10] >> 3);
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for (i = 0; i < 6; i++)
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input_report_abs(dev, spaceorb_axes[i], axes[i] - ((axes[i] & 0x200) ? 1024 : 0));
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for (i = 0; i < 6; i++)
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input_report_key(dev, spaceorb_buttons[i], (data[1] >> i) & 1);
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break;
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case 'K': /* Button data */
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if (spaceorb->idx != 5) return;
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for (i = 0; i < 6; i++)
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input_report_key(dev, spaceorb_buttons[i], (data[2] >> i) & 1);
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break;
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case 'E': /* Error packet */
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if (spaceorb->idx != 4) return;
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printk(KERN_ERR "spaceorb: Device error. [ ");
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for (i = 0; i < 7; i++) if (data[1] & (1 << i)) printk("%s ", spaceorb_errors[i]);
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printk("]\n");
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break;
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}
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input_sync(dev);
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}
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static irqreturn_t spaceorb_interrupt(struct serio *serio,
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unsigned char data, unsigned int flags)
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{
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struct spaceorb* spaceorb = serio_get_drvdata(serio);
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if (~data & 0x80) {
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if (spaceorb->idx) spaceorb_process_packet(spaceorb);
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spaceorb->idx = 0;
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}
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if (spaceorb->idx < SPACEORB_MAX_LENGTH)
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spaceorb->data[spaceorb->idx++] = data & 0x7f;
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return IRQ_HANDLED;
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}
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/*
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* spaceorb_disconnect() is the opposite of spaceorb_connect()
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*/
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static void spaceorb_disconnect(struct serio *serio)
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{
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struct spaceorb* spaceorb = serio_get_drvdata(serio);
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serio_close(serio);
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serio_set_drvdata(serio, NULL);
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input_unregister_device(spaceorb->dev);
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kfree(spaceorb);
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}
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/*
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* spaceorb_connect() is the routine that is called when someone adds a
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* new serio device that supports SpaceOrb/Avenger protocol and registers
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* it as an input device.
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*/
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static int spaceorb_connect(struct serio *serio, struct serio_driver *drv)
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{
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struct spaceorb *spaceorb;
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struct input_dev *input_dev;
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int err = -ENOMEM;
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int i;
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spaceorb = kzalloc(sizeof(struct spaceorb), GFP_KERNEL);
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input_dev = input_allocate_device();
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if (!spaceorb || !input_dev)
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goto fail;
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spaceorb->dev = input_dev;
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snprintf(spaceorb->phys, sizeof(spaceorb->phys), "%s/input0", serio->phys);
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input_dev->name = "SpaceTec SpaceOrb 360 / Avenger";
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input_dev->phys = spaceorb->phys;
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input_dev->id.bustype = BUS_RS232;
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input_dev->id.vendor = SERIO_SPACEORB;
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input_dev->id.product = 0x0001;
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input_dev->id.version = 0x0100;
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input_dev->cdev.dev = &serio->dev;
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input_dev->private = spaceorb;
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input_dev->evbit[0] = BIT(EV_KEY) | BIT(EV_ABS);
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for (i = 0; i < 6; i++)
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set_bit(spaceorb_buttons[i], input_dev->keybit);
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for (i = 0; i < 6; i++)
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input_set_abs_params(input_dev, spaceorb_axes[i], -508, 508, 0, 0);
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serio_set_drvdata(serio, spaceorb);
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err = serio_open(serio, drv);
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if (err)
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goto fail;
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input_register_device(spaceorb->dev);
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return 0;
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fail: serio_set_drvdata(serio, NULL);
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input_free_device(input_dev);
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kfree(spaceorb);
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return err;
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}
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/*
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* The serio driver structure.
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*/
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static struct serio_device_id spaceorb_serio_ids[] = {
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{
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.type = SERIO_RS232,
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.proto = SERIO_SPACEORB,
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.id = SERIO_ANY,
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.extra = SERIO_ANY,
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},
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{ 0 }
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};
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MODULE_DEVICE_TABLE(serio, spaceorb_serio_ids);
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static struct serio_driver spaceorb_drv = {
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.driver = {
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.name = "spaceorb",
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},
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.description = DRIVER_DESC,
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.id_table = spaceorb_serio_ids,
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.interrupt = spaceorb_interrupt,
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.connect = spaceorb_connect,
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.disconnect = spaceorb_disconnect,
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};
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/*
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* The functions for inserting/removing us as a module.
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*/
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static int __init spaceorb_init(void)
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{
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serio_register_driver(&spaceorb_drv);
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return 0;
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}
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static void __exit spaceorb_exit(void)
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{
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serio_unregister_driver(&spaceorb_drv);
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}
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module_init(spaceorb_init);
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module_exit(spaceorb_exit);
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