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linux/sound/isa/sb/es968.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

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/*
card-es968.c - driver for ESS AudioDrive ES968 based soundcards.
Copyright (C) 1999 by Massimo Piccioni <dafastidio@libero.it>
Thanks to Pierfrancesco 'qM2' Passerini.
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 <sound/driver.h>
#include <linux/init.h>
#include <linux/time.h>
#include <linux/pnp.h>
#include <linux/moduleparam.h>
#include <sound/core.h>
#include <sound/initval.h>
#include <sound/sb.h>
#define PFX "es968: "
MODULE_AUTHOR("Massimo Piccioni <dafastidio@libero.it>");
MODULE_DESCRIPTION("ESS AudioDrive ES968");
MODULE_LICENSE("GPL");
MODULE_SUPPORTED_DEVICE("{{ESS,AudioDrive ES968}}");
static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX; /* Index 0-MAX */
static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR; /* ID for this card */
static int enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_ISAPNP; /* Enable this card */
static long port[SNDRV_CARDS] = SNDRV_DEFAULT_PORT; /* PnP setup */
static int irq[SNDRV_CARDS] = SNDRV_DEFAULT_IRQ; /* Pnp setup */
static int dma8[SNDRV_CARDS] = SNDRV_DEFAULT_DMA; /* PnP setup */
module_param_array(index, int, NULL, 0444);
MODULE_PARM_DESC(index, "Index value for es968 based soundcard.");
module_param_array(id, charp, NULL, 0444);
MODULE_PARM_DESC(id, "ID string for es968 based soundcard.");
module_param_array(enable, bool, NULL, 0444);
MODULE_PARM_DESC(enable, "Enable es968 based soundcard.");
module_param_array(port, long, NULL, 0444);
MODULE_PARM_DESC(port, "Port # for es968 driver.");
module_param_array(irq, int, NULL, 0444);
MODULE_PARM_DESC(irq, "IRQ # for es968 driver.");
module_param_array(dma8, int, NULL, 0444);
MODULE_PARM_DESC(dma8, "8-bit DMA # for es968 driver.");
struct snd_card_es968 {
struct pnp_dev *dev;
struct snd_sb *chip;
};
static struct pnp_card_device_id snd_es968_pnpids[] = {
{ .id = "ESS0968", .devs = { { "@@@0968" }, } },
{ .id = "", } /* end */
};
MODULE_DEVICE_TABLE(pnp_card, snd_es968_pnpids);
#define DRIVER_NAME "snd-card-es968"
static irqreturn_t snd_card_es968_interrupt(int irq, void *dev_id)
{
struct snd_sb *chip = dev_id;
if (chip->open & SB_OPEN_PCM) {
return snd_sb8dsp_interrupt(chip);
} else {
return snd_sb8dsp_midi_interrupt(chip);
}
}
static int __devinit snd_card_es968_pnp(int dev, struct snd_card_es968 *acard,
struct pnp_card_link *card,
const struct pnp_card_device_id *id)
{
struct pnp_dev *pdev;
struct pnp_resource_table *cfg = kmalloc(sizeof(*cfg), GFP_KERNEL);
int err;
if (!cfg)
return -ENOMEM;
acard->dev = pnp_request_card_device(card, id->devs[0].id, NULL);
if (acard->dev == NULL) {
kfree(cfg);
return -ENODEV;
}
pdev = acard->dev;
pnp_init_resource_table(cfg);
/* override resources */
if (port[dev] != SNDRV_AUTO_PORT)
pnp_resource_change(&cfg->port_resource[0], port[dev], 16);
if (dma8[dev] != SNDRV_AUTO_DMA)
pnp_resource_change(&cfg->dma_resource[0], dma8[dev], 1);
if (irq[dev] != SNDRV_AUTO_IRQ)
pnp_resource_change(&cfg->irq_resource[0], irq[dev], 1);
if ((pnp_manual_config_dev(pdev, cfg, 0)) < 0)
snd_printk(KERN_ERR PFX "AUDIO the requested resources are invalid, using auto config\n");
err = pnp_activate_dev(pdev);
if (err < 0) {
snd_printk(KERN_ERR PFX "AUDIO pnp configure failure\n");
kfree(cfg);
return err;
}
port[dev] = pnp_port_start(pdev, 0);
dma8[dev] = pnp_dma(pdev, 1);
irq[dev] = pnp_irq(pdev, 0);
kfree(cfg);
return 0;
}
static int __devinit snd_card_es968_probe(int dev,
struct pnp_card_link *pcard,
const struct pnp_card_device_id *pid)
{
int error;
struct snd_sb *chip;
struct snd_card *card;
struct snd_card_es968 *acard;
if ((card = snd_card_new(index[dev], id[dev], THIS_MODULE,
sizeof(struct snd_card_es968))) == NULL)
return -ENOMEM;
acard = card->private_data;
if ((error = snd_card_es968_pnp(dev, acard, pcard, pid))) {
snd_card_free(card);
return error;
}
snd_card_set_dev(card, &pcard->card->dev);
if ((error = snd_sbdsp_create(card, port[dev],
irq[dev],
snd_card_es968_interrupt,
dma8[dev],
-1,
SB_HW_AUTO, &chip)) < 0) {
snd_card_free(card);
return error;
}
acard->chip = chip;
if ((error = snd_sb8dsp_pcm(chip, 0, NULL)) < 0) {
snd_card_free(card);
return error;
}
if ((error = snd_sbmixer_new(chip)) < 0) {
snd_card_free(card);
return error;
}
if ((error = snd_sb8dsp_midi(chip, 0, NULL)) < 0) {
snd_card_free(card);
return error;
}
strcpy(card->driver, "ES968");
strcpy(card->shortname, "ESS ES968");
sprintf(card->longname, "%s soundcard, %s at 0x%lx, irq %d, dma %d",
card->shortname, chip->name, chip->port, irq[dev], dma8[dev]);
if ((error = snd_card_register(card)) < 0) {
snd_card_free(card);
return error;
}
pnp_set_card_drvdata(pcard, card);
return 0;
}
static unsigned int __devinitdata es968_devices;
static int __devinit snd_es968_pnp_detect(struct pnp_card_link *card,
const struct pnp_card_device_id *id)
{
static int dev;
int res;
for ( ; dev < SNDRV_CARDS; dev++) {
if (!enable[dev])
continue;
res = snd_card_es968_probe(dev, card, id);
if (res < 0)
return res;
dev++;
es968_devices++;
return 0;
}
return -ENODEV;
}
static void __devexit snd_es968_pnp_remove(struct pnp_card_link * pcard)
{
snd_card_free(pnp_get_card_drvdata(pcard));
pnp_set_card_drvdata(pcard, NULL);
}
#ifdef CONFIG_PM
static int snd_es968_pnp_suspend(struct pnp_card_link *pcard, pm_message_t state)
{
struct snd_card *card = pnp_get_card_drvdata(pcard);
struct snd_card_es968 *acard = card->private_data;
struct snd_sb *chip = acard->chip;
snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
snd_pcm_suspend_all(chip->pcm);
snd_sbmixer_suspend(chip);
return 0;
}
static int snd_es968_pnp_resume(struct pnp_card_link *pcard)
{
struct snd_card *card = pnp_get_card_drvdata(pcard);
struct snd_card_es968 *acard = card->private_data;
struct snd_sb *chip = acard->chip;
snd_sbdsp_reset(chip);
snd_sbmixer_resume(chip);
snd_power_change_state(card, SNDRV_CTL_POWER_D0);
return 0;
}
#endif
static struct pnp_card_driver es968_pnpc_driver = {
.flags = PNP_DRIVER_RES_DISABLE,
.name = "es968",
.id_table = snd_es968_pnpids,
.probe = snd_es968_pnp_detect,
.remove = __devexit_p(snd_es968_pnp_remove),
#ifdef CONFIG_PM
.suspend = snd_es968_pnp_suspend,
.resume = snd_es968_pnp_resume,
#endif
};
static int __init alsa_card_es968_init(void)
{
int err = pnp_register_card_driver(&es968_pnpc_driver);
if (err)
return err;
if (!es968_devices) {
pnp_unregister_card_driver(&es968_pnpc_driver);
#ifdef MODULE
snd_printk(KERN_ERR "no ES968 based soundcards found\n");
#endif
return -ENODEV;
}
return 0;
}
static void __exit alsa_card_es968_exit(void)
{
pnp_unregister_card_driver(&es968_pnpc_driver);
}
module_init(alsa_card_es968_init)
module_exit(alsa_card_es968_exit)
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