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linux-next/sound/arm/pxa2xx-pcm.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

369 lines
9.5 KiB
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/*
* linux/sound/arm/pxa2xx-pcm.c -- ALSA PCM interface for the Intel PXA2xx chip
*
* Author: Nicolas Pitre
* Created: Nov 30, 2004
* Copyright: (C) 2004 MontaVista Software, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/dma-mapping.h>
#include <sound/driver.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <asm/dma.h>
#include <asm/hardware.h>
#include <asm/arch/pxa-regs.h>
#include "pxa2xx-pcm.h"
static const struct snd_pcm_hardware pxa2xx_pcm_hardware = {
.info = SNDRV_PCM_INFO_MMAP |
SNDRV_PCM_INFO_MMAP_VALID |
SNDRV_PCM_INFO_INTERLEAVED |
SNDRV_PCM_INFO_PAUSE,
.formats = SNDRV_PCM_FMTBIT_S16_LE,
.period_bytes_min = 32,
.period_bytes_max = 8192 - 32,
.periods_min = 1,
.periods_max = PAGE_SIZE/sizeof(pxa_dma_desc),
.buffer_bytes_max = 128 * 1024,
.fifo_size = 32,
};
struct pxa2xx_runtime_data {
int dma_ch;
struct pxa2xx_pcm_dma_params *params;
pxa_dma_desc *dma_desc_array;
dma_addr_t dma_desc_array_phys;
};
static int pxa2xx_pcm_hw_params(struct snd_pcm_substream *substream,
struct snd_pcm_hw_params *params)
{
struct snd_pcm_runtime *runtime = substream->runtime;
struct pxa2xx_runtime_data *rtd = runtime->private_data;
size_t totsize = params_buffer_bytes(params);
size_t period = params_period_bytes(params);
pxa_dma_desc *dma_desc;
dma_addr_t dma_buff_phys, next_desc_phys;
snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);
runtime->dma_bytes = totsize;
dma_desc = rtd->dma_desc_array;
next_desc_phys = rtd->dma_desc_array_phys;
dma_buff_phys = runtime->dma_addr;
do {
next_desc_phys += sizeof(pxa_dma_desc);
dma_desc->ddadr = next_desc_phys;
if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
dma_desc->dsadr = dma_buff_phys;
dma_desc->dtadr = rtd->params->dev_addr;
} else {
dma_desc->dsadr = rtd->params->dev_addr;
dma_desc->dtadr = dma_buff_phys;
}
if (period > totsize)
period = totsize;
dma_desc->dcmd = rtd->params->dcmd | period | DCMD_ENDIRQEN;
dma_desc++;
dma_buff_phys += period;
} while (totsize -= period);
dma_desc[-1].ddadr = rtd->dma_desc_array_phys;
return 0;
}
static int pxa2xx_pcm_hw_free(struct snd_pcm_substream *substream)
{
struct pxa2xx_runtime_data *rtd = substream->runtime->private_data;
*rtd->params->drcmr = 0;
snd_pcm_set_runtime_buffer(substream, NULL);
return 0;
}
static int pxa2xx_pcm_prepare(struct snd_pcm_substream *substream)
{
struct pxa2xx_pcm_client *client = substream->private_data;
struct snd_pcm_runtime *runtime = substream->runtime;
struct pxa2xx_runtime_data *rtd = runtime->private_data;
DCSR(rtd->dma_ch) &= ~DCSR_RUN;
DCSR(rtd->dma_ch) = 0;
DCMD(rtd->dma_ch) = 0;
*rtd->params->drcmr = rtd->dma_ch | DRCMR_MAPVLD;
return client->prepare(substream);
}
static int pxa2xx_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
{
struct pxa2xx_runtime_data *rtd = substream->runtime->private_data;
int ret = 0;
switch (cmd) {
case SNDRV_PCM_TRIGGER_START:
DDADR(rtd->dma_ch) = rtd->dma_desc_array_phys;
DCSR(rtd->dma_ch) = DCSR_RUN;
break;
case SNDRV_PCM_TRIGGER_STOP:
case SNDRV_PCM_TRIGGER_SUSPEND:
case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
DCSR(rtd->dma_ch) &= ~DCSR_RUN;
break;
case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
DCSR(rtd->dma_ch) |= DCSR_RUN;
break;
default:
ret = -EINVAL;
}
return ret;
}
static void pxa2xx_pcm_dma_irq(int dma_ch, void *dev_id)
{
struct snd_pcm_substream *substream = dev_id;
struct pxa2xx_runtime_data *rtd = substream->runtime->private_data;
int dcsr;
dcsr = DCSR(dma_ch);
DCSR(dma_ch) = dcsr & ~DCSR_STOPIRQEN;
if (dcsr & DCSR_ENDINTR) {
snd_pcm_period_elapsed(substream);
} else {
printk( KERN_ERR "%s: DMA error on channel %d (DCSR=%#x)\n",
rtd->params->name, dma_ch, dcsr );
snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN);
}
}
static snd_pcm_uframes_t pxa2xx_pcm_pointer(struct snd_pcm_substream *substream)
{
struct snd_pcm_runtime *runtime = substream->runtime;
struct pxa2xx_runtime_data *rtd = runtime->private_data;
dma_addr_t ptr = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) ?
DSADR(rtd->dma_ch) : DTADR(rtd->dma_ch);
snd_pcm_uframes_t x = bytes_to_frames(runtime, ptr - runtime->dma_addr);
if (x == runtime->buffer_size)
x = 0;
return x;
}
static int
pxa2xx_pcm_hw_rule_mult32(struct snd_pcm_hw_params *params, struct snd_pcm_hw_rule *rule)
{
struct snd_interval *i = hw_param_interval(params, rule->var);
int changed = 0;
if (i->min & 31) {
i->min = (i->min & ~31) + 32;
i->openmin = 0;
changed = 1;
}
if (i->max & 31) {
i->max &= ~31;
i->openmax = 0;
changed = 1;
}
return changed;
}
static int pxa2xx_pcm_open(struct snd_pcm_substream *substream)
{
struct pxa2xx_pcm_client *client = substream->private_data;
struct snd_pcm_runtime *runtime = substream->runtime;
struct pxa2xx_runtime_data *rtd;
int ret;
runtime->hw = pxa2xx_pcm_hardware;
/*
* For mysterious reasons (and despite what the manual says)
* playback samples are lost if the DMA count is not a multiple
* of the DMA burst size. Let's add a rule to enforce that.
*/
ret = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
pxa2xx_pcm_hw_rule_mult32, NULL,
SNDRV_PCM_HW_PARAM_PERIOD_BYTES, -1);
if (ret)
goto out;
ret = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_BUFFER_BYTES,
pxa2xx_pcm_hw_rule_mult32, NULL,
SNDRV_PCM_HW_PARAM_BUFFER_BYTES, -1);
if (ret)
goto out;
ret = -ENOMEM;
rtd = kmalloc(sizeof(*rtd), GFP_KERNEL);
if (!rtd)
goto out;
rtd->dma_desc_array =
dma_alloc_writecombine(substream->pcm->card->dev, PAGE_SIZE,
&rtd->dma_desc_array_phys, GFP_KERNEL);
if (!rtd->dma_desc_array)
goto err1;
rtd->params = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) ?
client->playback_params : client->capture_params;
ret = pxa_request_dma(rtd->params->name, DMA_PRIO_LOW,
pxa2xx_pcm_dma_irq, substream);
if (ret < 0)
goto err2;
rtd->dma_ch = ret;
runtime->private_data = rtd;
ret = client->startup(substream);
if (!ret)
goto out;
pxa_free_dma(rtd->dma_ch);
err2:
dma_free_writecombine(substream->pcm->card->dev, PAGE_SIZE,
rtd->dma_desc_array, rtd->dma_desc_array_phys);
err1:
kfree(rtd);
out:
return ret;
}
static int pxa2xx_pcm_close(struct snd_pcm_substream *substream)
{
struct pxa2xx_pcm_client *client = substream->private_data;
struct pxa2xx_runtime_data *rtd = substream->runtime->private_data;
pxa_free_dma(rtd->dma_ch);
client->shutdown(substream);
dma_free_writecombine(substream->pcm->card->dev, PAGE_SIZE,
rtd->dma_desc_array, rtd->dma_desc_array_phys);
kfree(rtd);
return 0;
}
static int
pxa2xx_pcm_mmap(struct snd_pcm_substream *substream, struct vm_area_struct *vma)
{
struct snd_pcm_runtime *runtime = substream->runtime;
return dma_mmap_writecombine(substream->pcm->card->dev, vma,
runtime->dma_area,
runtime->dma_addr,
runtime->dma_bytes);
}
static struct snd_pcm_ops pxa2xx_pcm_ops = {
.open = pxa2xx_pcm_open,
.close = pxa2xx_pcm_close,
.ioctl = snd_pcm_lib_ioctl,
.hw_params = pxa2xx_pcm_hw_params,
.hw_free = pxa2xx_pcm_hw_free,
.prepare = pxa2xx_pcm_prepare,
.trigger = pxa2xx_pcm_trigger,
.pointer = pxa2xx_pcm_pointer,
.mmap = pxa2xx_pcm_mmap,
};
static int pxa2xx_pcm_preallocate_dma_buffer(struct snd_pcm *pcm, int stream)
{
struct snd_pcm_substream *substream = pcm->streams[stream].substream;
struct snd_dma_buffer *buf = &substream->dma_buffer;
size_t size = pxa2xx_pcm_hardware.buffer_bytes_max;
buf->dev.type = SNDRV_DMA_TYPE_DEV;
buf->dev.dev = pcm->card->dev;
buf->private_data = NULL;
buf->area = dma_alloc_writecombine(pcm->card->dev, size,
&buf->addr, GFP_KERNEL);
if (!buf->area)
return -ENOMEM;
buf->bytes = size;
return 0;
}
static void pxa2xx_pcm_free_dma_buffers(struct snd_pcm *pcm)
{
struct snd_pcm_substream *substream;
struct snd_dma_buffer *buf;
int stream;
for (stream = 0; stream < 2; stream++) {
substream = pcm->streams[stream].substream;
if (!substream)
continue;
buf = &substream->dma_buffer;
if (!buf->area)
continue;
dma_free_writecombine(pcm->card->dev, buf->bytes,
buf->area, buf->addr);
buf->area = NULL;
}
}
static u64 pxa2xx_pcm_dmamask = 0xffffffff;
int pxa2xx_pcm_new(struct snd_card *card, struct pxa2xx_pcm_client *client,
struct snd_pcm **rpcm)
{
struct snd_pcm *pcm;
int play = client->playback_params ? 1 : 0;
int capt = client->capture_params ? 1 : 0;
int ret;
ret = snd_pcm_new(card, "PXA2xx-PCM", 0, play, capt, &pcm);
if (ret)
goto out;
pcm->private_data = client;
pcm->private_free = pxa2xx_pcm_free_dma_buffers;
if (!card->dev->dma_mask)
card->dev->dma_mask = &pxa2xx_pcm_dmamask;
if (!card->dev->coherent_dma_mask)
card->dev->coherent_dma_mask = 0xffffffff;
if (play) {
int stream = SNDRV_PCM_STREAM_PLAYBACK;
snd_pcm_set_ops(pcm, stream, &pxa2xx_pcm_ops);
ret = pxa2xx_pcm_preallocate_dma_buffer(pcm, stream);
if (ret)
goto out;
}
if (capt) {
int stream = SNDRV_PCM_STREAM_CAPTURE;
snd_pcm_set_ops(pcm, stream, &pxa2xx_pcm_ops);
ret = pxa2xx_pcm_preallocate_dma_buffer(pcm, stream);
if (ret)
goto out;
}
if (rpcm)
*rpcm = pcm;
ret = 0;
out:
return ret;
}
EXPORT_SYMBOL(pxa2xx_pcm_new);
MODULE_AUTHOR("Nicolas Pitre");
MODULE_DESCRIPTION("Intel PXA2xx PCM DMA module");
MODULE_LICENSE("GPL");
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