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linux/include/sound/mpu401.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

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#ifndef __SOUND_MPU401_H
#define __SOUND_MPU401_H
/*
* Header file for MPU-401 and compatible cards
* Copyright (c) by Jaroslav Kysela <perex@suse.cz>
*
*
* 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
*
*/
#include "rawmidi.h"
#include <linux/interrupt.h>
#define MPU401_HW_MPU401 1 /* native MPU401 */
#define MPU401_HW_SB 2 /* SoundBlaster MPU-401 UART */
#define MPU401_HW_ES1688 3 /* AudioDrive ES1688 MPU-401 UART */
#define MPU401_HW_OPL3SA2 4 /* Yamaha OPL3-SA2 */
#define MPU401_HW_SONICVIBES 5 /* S3 SonicVibes */
#define MPU401_HW_CS4232 6 /* CS4232 */
#define MPU401_HW_ES18XX 7 /* AudioDrive ES18XX MPU-401 UART */
#define MPU401_HW_FM801 8 /* ForteMedia FM801 */
#define MPU401_HW_TRID4DWAVE 9 /* Trident 4DWave */
#define MPU401_HW_AZT2320 10 /* Aztech AZT2320 */
#define MPU401_HW_ALS100 11 /* Avance Logic ALS100 */
#define MPU401_HW_ICE1712 12 /* Envy24 */
#define MPU401_HW_VIA686A 13 /* VIA 82C686A */
#define MPU401_HW_YMFPCI 14 /* YMF DS-XG PCI */
#define MPU401_HW_CMIPCI 15 /* CMIPCI MPU-401 UART */
#define MPU401_HW_ALS4000 16 /* Avance Logic ALS4000 */
#define MPU401_HW_INTEL8X0 17 /* Intel8x0 driver */
#define MPU401_HW_PC98II 18 /* Roland PC98II */
#define MPU401_HW_AUREAL 19 /* Aureal Vortex */
#define MPU401_INFO_INPUT (1 << 0) /* input stream */
#define MPU401_INFO_OUTPUT (1 << 1) /* output stream */
#define MPU401_INFO_INTEGRATED (1 << 2) /* integrated h/w port */
#define MPU401_INFO_MMIO (1 << 3) /* MMIO access */
#define MPU401_INFO_TX_IRQ (1 << 4) /* independent TX irq */
#define MPU401_MODE_BIT_INPUT 0
#define MPU401_MODE_BIT_OUTPUT 1
#define MPU401_MODE_BIT_INPUT_TRIGGER 2
#define MPU401_MODE_BIT_OUTPUT_TRIGGER 3
#define MPU401_MODE_INPUT (1<<MPU401_MODE_BIT_INPUT)
#define MPU401_MODE_OUTPUT (1<<MPU401_MODE_BIT_OUTPUT)
#define MPU401_MODE_INPUT_TRIGGER (1<<MPU401_MODE_BIT_INPUT_TRIGGER)
#define MPU401_MODE_OUTPUT_TRIGGER (1<<MPU401_MODE_BIT_OUTPUT_TRIGGER)
#define MPU401_MODE_INPUT_TIMER (1<<0)
#define MPU401_MODE_OUTPUT_TIMER (1<<1)
struct snd_mpu401 {
struct snd_rawmidi *rmidi;
unsigned short hardware; /* MPU401_HW_XXXX */
unsigned int info_flags; /* MPU401_INFO_XXX */
unsigned long port; /* base port of MPU-401 chip */
unsigned long cport; /* port + 1 (usually) */
struct resource *res; /* port resource */
int irq; /* IRQ number of MPU-401 chip (-1 = poll) */
int irq_flags;
unsigned long mode; /* MPU401_MODE_XXXX */
int timer_invoked;
int (*open_input) (struct snd_mpu401 * mpu);
void (*close_input) (struct snd_mpu401 * mpu);
int (*open_output) (struct snd_mpu401 * mpu);
void (*close_output) (struct snd_mpu401 * mpu);
void *private_data;
struct snd_rawmidi_substream *substream_input;
struct snd_rawmidi_substream *substream_output;
spinlock_t input_lock;
spinlock_t output_lock;
spinlock_t timer_lock;
struct timer_list timer;
void (*write) (struct snd_mpu401 * mpu, unsigned char data, unsigned long addr);
unsigned char (*read) (struct snd_mpu401 *mpu, unsigned long addr);
};
/* I/O ports */
#define MPU401C(mpu) (mpu)->cport
#define MPU401D(mpu) (mpu)->port
/*
*/
irqreturn_t snd_mpu401_uart_interrupt(int irq, void *dev_id);
irqreturn_t snd_mpu401_uart_interrupt_tx(int irq, void *dev_id);
int snd_mpu401_uart_new(struct snd_card *card,
int device,
unsigned short hardware,
unsigned long port,
unsigned int info_flags,
int irq,
int irq_flags,
struct snd_rawmidi ** rrawmidi);
#endif /* __SOUND_MPU401_H */
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