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linux-hardened/include/linux/hiddev.h
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

240 lines
7.1 KiB
C
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#ifndef _HIDDEV_H
#define _HIDDEV_H
/*
* $Id: hiddev.h,v 1.2 2001/04/26 11:26:09 vojtech Exp $
*
* Copyright (c) 1999-2000 Vojtech Pavlik
*
* Sponsored by SuSE
*/
/*
* 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@suse.cz>, or by paper mail:
* Vojtech Pavlik, Ucitelska 1576, Prague 8, 182 00 Czech Republic
*/
/*
* The event structure itself
*/
struct hiddev_event {
unsigned hid;
signed int value;
};
struct hiddev_devinfo {
__u32 bustype;
__u32 busnum;
__u32 devnum;
__u32 ifnum;
__s16 vendor;
__s16 product;
__s16 version;
__u32 num_applications;
};
struct hiddev_collection_info {
__u32 index;
__u32 type;
__u32 usage;
__u32 level;
};
#define HID_STRING_SIZE 256
struct hiddev_string_descriptor {
__s32 index;
char value[HID_STRING_SIZE];
};
struct hiddev_report_info {
__u32 report_type;
__u32 report_id;
__u32 num_fields;
};
/* To do a GUSAGE/SUSAGE, fill in at least usage_code, report_type and
* report_id. Set report_id to REPORT_ID_UNKNOWN if the rest of the fields
* are unknown. Otherwise use a usage_ref struct filled in from a previous
* successful GUSAGE call to save time. To actually send a value to the
* device, perform a SUSAGE first, followed by a SREPORT. An INITREPORT or a
* GREPORT isn't necessary for a GUSAGE to return valid data.
*/
#define HID_REPORT_ID_UNKNOWN 0xffffffff
#define HID_REPORT_ID_FIRST 0x00000100
#define HID_REPORT_ID_NEXT 0x00000200
#define HID_REPORT_ID_MASK 0x000000ff
#define HID_REPORT_ID_MAX 0x000000ff
#define HID_REPORT_TYPE_INPUT 1
#define HID_REPORT_TYPE_OUTPUT 2
#define HID_REPORT_TYPE_FEATURE 3
#define HID_REPORT_TYPE_MIN 1
#define HID_REPORT_TYPE_MAX 3
struct hiddev_field_info {
__u32 report_type;
__u32 report_id;
__u32 field_index;
__u32 maxusage;
__u32 flags;
__u32 physical; /* physical usage for this field */
__u32 logical; /* logical usage for this field */
__u32 application; /* application usage for this field */
__s32 logical_minimum;
__s32 logical_maximum;
__s32 physical_minimum;
__s32 physical_maximum;
__u32 unit_exponent;
__u32 unit;
};
/* Fill in report_type, report_id and field_index to get the information on a
* field.
*/
#define HID_FIELD_CONSTANT 0x001
#define HID_FIELD_VARIABLE 0x002
#define HID_FIELD_RELATIVE 0x004
#define HID_FIELD_WRAP 0x008
#define HID_FIELD_NONLINEAR 0x010
#define HID_FIELD_NO_PREFERRED 0x020
#define HID_FIELD_NULL_STATE 0x040
#define HID_FIELD_VOLATILE 0x080
#define HID_FIELD_BUFFERED_BYTE 0x100
struct hiddev_usage_ref {
__u32 report_type;
__u32 report_id;
__u32 field_index;
__u32 usage_index;
__u32 usage_code;
__s32 value;
};
/* hiddev_usage_ref_multi is used for sending multiple bytes to a control.
* It really manifests itself as setting the value of consecutive usages */
#define HID_MAX_MULTI_USAGES 1024
struct hiddev_usage_ref_multi {
struct hiddev_usage_ref uref;
__u32 num_values;
__s32 values[HID_MAX_MULTI_USAGES];
};
/* FIELD_INDEX_NONE is returned in read() data from the kernel when flags
* is set to (HIDDEV_FLAG_UREF | HIDDEV_FLAG_REPORT) and a new report has
* been sent by the device
*/
#define HID_FIELD_INDEX_NONE 0xffffffff
/*
* Protocol version.
*/
#define HID_VERSION 0x010004
/*
* IOCTLs (0x00 - 0x7f)
*/
#define HIDIOCGVERSION _IOR('H', 0x01, int)
#define HIDIOCAPPLICATION _IO('H', 0x02)
#define HIDIOCGDEVINFO _IOR('H', 0x03, struct hiddev_devinfo)
#define HIDIOCGSTRING _IOR('H', 0x04, struct hiddev_string_descriptor)
#define HIDIOCINITREPORT _IO('H', 0x05)
#define HIDIOCGNAME(len) _IOC(_IOC_READ, 'H', 0x06, len)
#define HIDIOCGREPORT _IOW('H', 0x07, struct hiddev_report_info)
#define HIDIOCSREPORT _IOW('H', 0x08, struct hiddev_report_info)
#define HIDIOCGREPORTINFO _IOWR('H', 0x09, struct hiddev_report_info)
#define HIDIOCGFIELDINFO _IOWR('H', 0x0A, struct hiddev_field_info)
#define HIDIOCGUSAGE _IOWR('H', 0x0B, struct hiddev_usage_ref)
#define HIDIOCSUSAGE _IOW('H', 0x0C, struct hiddev_usage_ref)
#define HIDIOCGUCODE _IOWR('H', 0x0D, struct hiddev_usage_ref)
#define HIDIOCGFLAG _IOR('H', 0x0E, int)
#define HIDIOCSFLAG _IOW('H', 0x0F, int)
#define HIDIOCGCOLLECTIONINDEX _IOW('H', 0x10, struct hiddev_usage_ref)
#define HIDIOCGCOLLECTIONINFO _IOWR('H', 0x11, struct hiddev_collection_info)
#define HIDIOCGPHYS(len) _IOC(_IOC_READ, 'H', 0x12, len)
/* For writing/reading to multiple/consecutive usages */
#define HIDIOCGUSAGES _IOWR('H', 0x13, struct hiddev_usage_ref_multi)
#define HIDIOCSUSAGES _IOW('H', 0x14, struct hiddev_usage_ref_multi)
/*
* Flags to be used in HIDIOCSFLAG
*/
#define HIDDEV_FLAG_UREF 0x1
#define HIDDEV_FLAG_REPORT 0x2
#define HIDDEV_FLAGS 0x3
/* To traverse the input report descriptor info for a HID device, perform the
* following:
*
* rinfo.report_type = HID_REPORT_TYPE_INPUT;
* rinfo.report_id = HID_REPORT_ID_FIRST;
* ret = ioctl(fd, HIDIOCGREPORTINFO, &rinfo);
*
* while (ret >= 0) {
* for (i = 0; i < rinfo.num_fields; i++) {
* finfo.report_type = rinfo.report_type;
* finfo.report_id = rinfo.report_id;
* finfo.field_index = i;
* ioctl(fd, HIDIOCGFIELDINFO, &finfo);
* for (j = 0; j < finfo.maxusage; j++) {
* uref.field_index = i;
* uref.usage_index = j;
* ioctl(fd, HIDIOCGUCODE, &uref);
* ioctl(fd, HIDIOCGUSAGE, &uref);
* }
* }
* rinfo.report_id |= HID_REPORT_ID_NEXT;
* ret = ioctl(fd, HIDIOCGREPORTINFO, &rinfo);
* }
*/
#ifdef __KERNEL__
/*
* In-kernel definitions.
*/
struct hid_device;
struct hid_usage;
struct hid_field;
struct hid_report;
#ifdef CONFIG_USB_HIDDEV
int hiddev_connect(struct hid_device *);
void hiddev_disconnect(struct hid_device *);
void hiddev_hid_event(struct hid_device *hid, struct hid_field *field,
struct hid_usage *usage, __s32 value);
void hiddev_report_event(struct hid_device *hid, struct hid_report *report);
int __init hiddev_init(void);
void hiddev_exit(void);
#else
static inline int hiddev_connect(struct hid_device *hid) { return -1; }
static inline void hiddev_disconnect(struct hid_device *hid) { }
static inline void hiddev_hid_event(struct hid_device *hid, struct hid_field *field,
struct hid_usage *usage, __s32 value) { }
static inline void hiddev_report_event(struct hid_device *hid, struct hid_report *report) { }
static inline int hiddev_init(void) { return 0; }
static inline void hiddev_exit(void) { }
#endif
#endif
#endif
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