68f9672b13
Originally snd_hrtimer_callback() used iprtd->period_time for
some jiffies based estimation to determine the right moment
to call snd_pcm_period_elapsed(). As timer drifts may well be a
problem, this was changed in commit b4e82b5b78
to be based
on buffer transmission progress, using iprtd->offset and
runtime->buffer_size to calculate the amount of data since last
period had elapsed.
Unfortunately, iprtd->offset counts in bytes, while
runtime->buffer_size counts frames, so adding these to find some
delta is like comparing apples and oranges, and eventually results
in negative delta values every now and then. This is no big harm,
because it simply causes snd_pcm_period_elapsed() being called
more often than necessary, as negative delta is taken for a
large unsigned value by implicit conversion rule.
Nonetheless, the calculation is broken, so one would replace
the runtime->buffer_size by its equivalent in bytes.
But then, there are chances snd_pcm_period_elapsed() is called
late, because calculating the moment for the elapsed period
into delta is based against the iprtd->last_offset, which is not
necessarily the first byte of the period in question, but some
random byte which the FIQ handler left us with in r8/r9 by
accident. Again, negative impact is low, as there are plenty of
periods already prefilled with data, and snd_pcm_period_elapsed()
will probably be called latest when the following period is
reached. However, the calculation is conceptually broken, and we
are best off removing the clever stuff altogether.
snd_pcm_period_elapsed() is now simply called once everytime
snd_hrtimer_callback() is run, which may not be most accurate,
but at least this way we are quite sure we dont miss an end of
period. There is not much extra effort wasted by superfluous
calls to snd_pcm_period_elapsed(), as the timer frequency
closely matches the period size anyway.
Signed-off-by: Oskar Schirmer <oskar@scara.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
395 lines
9.2 KiB
C
395 lines
9.2 KiB
C
/*
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* imx-pcm-fiq.c -- ALSA Soc Audio Layer
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*
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* Copyright 2009 Sascha Hauer <s.hauer@pengutronix.de>
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*
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* This code is based on code copyrighted by Freescale,
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* Liam Girdwood, Javier Martin and probably others.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*/
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#include <linux/clk.h>
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#include <linux/delay.h>
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#include <linux/device.h>
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#include <linux/dma-mapping.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include <sound/core.h>
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#include <sound/dmaengine_pcm.h>
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#include <sound/initval.h>
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#include <sound/pcm.h>
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#include <sound/pcm_params.h>
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#include <sound/soc.h>
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#include <asm/fiq.h>
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#include <linux/platform_data/asoc-imx-ssi.h>
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#include "imx-ssi.h"
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#include "imx-pcm.h"
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struct imx_pcm_runtime_data {
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unsigned int period;
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int periods;
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unsigned long offset;
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struct hrtimer hrt;
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int poll_time_ns;
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struct snd_pcm_substream *substream;
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atomic_t running;
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};
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static enum hrtimer_restart snd_hrtimer_callback(struct hrtimer *hrt)
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{
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struct imx_pcm_runtime_data *iprtd =
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container_of(hrt, struct imx_pcm_runtime_data, hrt);
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struct snd_pcm_substream *substream = iprtd->substream;
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struct snd_pcm_runtime *runtime = substream->runtime;
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struct pt_regs regs;
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if (!atomic_read(&iprtd->running))
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return HRTIMER_NORESTART;
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get_fiq_regs(®s);
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if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
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iprtd->offset = regs.ARM_r8 & 0xffff;
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else
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iprtd->offset = regs.ARM_r9 & 0xffff;
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snd_pcm_period_elapsed(substream);
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hrtimer_forward_now(hrt, ns_to_ktime(iprtd->poll_time_ns));
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return HRTIMER_RESTART;
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}
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static struct fiq_handler fh = {
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.name = DRV_NAME,
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};
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static int snd_imx_pcm_hw_params(struct snd_pcm_substream *substream,
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struct snd_pcm_hw_params *params)
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{
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struct snd_pcm_runtime *runtime = substream->runtime;
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struct imx_pcm_runtime_data *iprtd = runtime->private_data;
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iprtd->periods = params_periods(params);
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iprtd->period = params_period_bytes(params);
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iprtd->offset = 0;
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iprtd->poll_time_ns = 1000000000 / params_rate(params) *
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params_period_size(params);
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snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);
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return 0;
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}
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static int snd_imx_pcm_prepare(struct snd_pcm_substream *substream)
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{
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struct snd_pcm_runtime *runtime = substream->runtime;
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struct imx_pcm_runtime_data *iprtd = runtime->private_data;
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struct pt_regs regs;
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get_fiq_regs(®s);
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if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
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regs.ARM_r8 = (iprtd->period * iprtd->periods - 1) << 16;
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else
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regs.ARM_r9 = (iprtd->period * iprtd->periods - 1) << 16;
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set_fiq_regs(®s);
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return 0;
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}
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static int fiq_enable;
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static int imx_pcm_fiq;
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static int snd_imx_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
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{
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struct snd_pcm_runtime *runtime = substream->runtime;
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struct imx_pcm_runtime_data *iprtd = runtime->private_data;
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switch (cmd) {
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case SNDRV_PCM_TRIGGER_START:
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case SNDRV_PCM_TRIGGER_RESUME:
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case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
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atomic_set(&iprtd->running, 1);
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hrtimer_start(&iprtd->hrt, ns_to_ktime(iprtd->poll_time_ns),
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HRTIMER_MODE_REL);
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if (++fiq_enable == 1)
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enable_fiq(imx_pcm_fiq);
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break;
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case SNDRV_PCM_TRIGGER_STOP:
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case SNDRV_PCM_TRIGGER_SUSPEND:
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case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
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atomic_set(&iprtd->running, 0);
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if (--fiq_enable == 0)
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disable_fiq(imx_pcm_fiq);
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break;
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default:
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return -EINVAL;
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}
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return 0;
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}
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static snd_pcm_uframes_t snd_imx_pcm_pointer(struct snd_pcm_substream *substream)
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{
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struct snd_pcm_runtime *runtime = substream->runtime;
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struct imx_pcm_runtime_data *iprtd = runtime->private_data;
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return bytes_to_frames(substream->runtime, iprtd->offset);
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}
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static struct snd_pcm_hardware snd_imx_hardware = {
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.info = SNDRV_PCM_INFO_INTERLEAVED |
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SNDRV_PCM_INFO_BLOCK_TRANSFER |
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SNDRV_PCM_INFO_MMAP |
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SNDRV_PCM_INFO_MMAP_VALID |
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SNDRV_PCM_INFO_PAUSE |
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SNDRV_PCM_INFO_RESUME,
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.formats = SNDRV_PCM_FMTBIT_S16_LE,
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.rate_min = 8000,
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.channels_min = 2,
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.channels_max = 2,
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.buffer_bytes_max = IMX_SSI_DMABUF_SIZE,
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.period_bytes_min = 128,
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.period_bytes_max = 16 * 1024,
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.periods_min = 4,
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.periods_max = 255,
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.fifo_size = 0,
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};
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static int snd_imx_open(struct snd_pcm_substream *substream)
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{
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struct snd_pcm_runtime *runtime = substream->runtime;
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struct imx_pcm_runtime_data *iprtd;
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int ret;
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iprtd = kzalloc(sizeof(*iprtd), GFP_KERNEL);
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if (iprtd == NULL)
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return -ENOMEM;
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runtime->private_data = iprtd;
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iprtd->substream = substream;
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atomic_set(&iprtd->running, 0);
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hrtimer_init(&iprtd->hrt, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
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iprtd->hrt.function = snd_hrtimer_callback;
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ret = snd_pcm_hw_constraint_integer(substream->runtime,
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SNDRV_PCM_HW_PARAM_PERIODS);
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if (ret < 0) {
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kfree(iprtd);
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return ret;
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}
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snd_soc_set_runtime_hwparams(substream, &snd_imx_hardware);
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return 0;
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}
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static int snd_imx_close(struct snd_pcm_substream *substream)
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{
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struct snd_pcm_runtime *runtime = substream->runtime;
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struct imx_pcm_runtime_data *iprtd = runtime->private_data;
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hrtimer_cancel(&iprtd->hrt);
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kfree(iprtd);
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return 0;
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}
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static int snd_imx_pcm_mmap(struct snd_pcm_substream *substream,
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struct vm_area_struct *vma)
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{
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struct snd_pcm_runtime *runtime = substream->runtime;
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int ret;
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ret = dma_mmap_writecombine(substream->pcm->card->dev, vma,
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runtime->dma_area, runtime->dma_addr, runtime->dma_bytes);
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pr_debug("%s: ret: %d %p 0x%08x 0x%08x\n", __func__, ret,
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runtime->dma_area,
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runtime->dma_addr,
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runtime->dma_bytes);
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return ret;
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}
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static struct snd_pcm_ops imx_pcm_ops = {
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.open = snd_imx_open,
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.close = snd_imx_close,
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.ioctl = snd_pcm_lib_ioctl,
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.hw_params = snd_imx_pcm_hw_params,
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.prepare = snd_imx_pcm_prepare,
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.trigger = snd_imx_pcm_trigger,
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.pointer = snd_imx_pcm_pointer,
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.mmap = snd_imx_pcm_mmap,
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};
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static int imx_pcm_preallocate_dma_buffer(struct snd_pcm *pcm, int stream)
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{
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struct snd_pcm_substream *substream = pcm->streams[stream].substream;
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struct snd_dma_buffer *buf = &substream->dma_buffer;
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size_t size = IMX_SSI_DMABUF_SIZE;
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buf->dev.type = SNDRV_DMA_TYPE_DEV;
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buf->dev.dev = pcm->card->dev;
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buf->private_data = NULL;
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buf->area = dma_alloc_writecombine(pcm->card->dev, size,
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&buf->addr, GFP_KERNEL);
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if (!buf->area)
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return -ENOMEM;
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buf->bytes = size;
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return 0;
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}
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static u64 imx_pcm_dmamask = DMA_BIT_MASK(32);
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static int imx_pcm_new(struct snd_soc_pcm_runtime *rtd)
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{
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struct snd_card *card = rtd->card->snd_card;
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struct snd_pcm *pcm = rtd->pcm;
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int ret = 0;
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if (!card->dev->dma_mask)
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card->dev->dma_mask = &imx_pcm_dmamask;
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if (!card->dev->coherent_dma_mask)
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card->dev->coherent_dma_mask = DMA_BIT_MASK(32);
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if (pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream) {
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ret = imx_pcm_preallocate_dma_buffer(pcm,
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SNDRV_PCM_STREAM_PLAYBACK);
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if (ret)
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goto out;
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}
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if (pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream) {
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ret = imx_pcm_preallocate_dma_buffer(pcm,
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SNDRV_PCM_STREAM_CAPTURE);
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if (ret)
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goto out;
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}
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out:
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return ret;
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}
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static int ssi_irq = 0;
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static int imx_pcm_fiq_new(struct snd_soc_pcm_runtime *rtd)
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{
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struct snd_pcm *pcm = rtd->pcm;
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struct snd_pcm_substream *substream;
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int ret;
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ret = imx_pcm_new(rtd);
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if (ret)
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return ret;
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substream = pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream;
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if (substream) {
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struct snd_dma_buffer *buf = &substream->dma_buffer;
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imx_ssi_fiq_tx_buffer = (unsigned long)buf->area;
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}
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substream = pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream;
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if (substream) {
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struct snd_dma_buffer *buf = &substream->dma_buffer;
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imx_ssi_fiq_rx_buffer = (unsigned long)buf->area;
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}
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set_fiq_handler(&imx_ssi_fiq_start,
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&imx_ssi_fiq_end - &imx_ssi_fiq_start);
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return 0;
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}
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static void imx_pcm_free(struct snd_pcm *pcm)
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{
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struct snd_pcm_substream *substream;
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struct snd_dma_buffer *buf;
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int stream;
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for (stream = 0; stream < 2; stream++) {
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substream = pcm->streams[stream].substream;
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if (!substream)
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continue;
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buf = &substream->dma_buffer;
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if (!buf->area)
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continue;
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dma_free_writecombine(pcm->card->dev, buf->bytes,
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buf->area, buf->addr);
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buf->area = NULL;
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}
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}
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static void imx_pcm_fiq_free(struct snd_pcm *pcm)
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{
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mxc_set_irq_fiq(ssi_irq, 0);
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release_fiq(&fh);
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imx_pcm_free(pcm);
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}
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static struct snd_soc_platform_driver imx_soc_platform_fiq = {
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.ops = &imx_pcm_ops,
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.pcm_new = imx_pcm_fiq_new,
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.pcm_free = imx_pcm_fiq_free,
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};
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int imx_pcm_fiq_init(struct platform_device *pdev,
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struct imx_pcm_fiq_params *params)
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{
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int ret;
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ret = claim_fiq(&fh);
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if (ret) {
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dev_err(&pdev->dev, "failed to claim fiq: %d", ret);
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return ret;
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}
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mxc_set_irq_fiq(params->irq, 1);
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ssi_irq = params->irq;
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imx_pcm_fiq = params->irq;
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imx_ssi_fiq_base = (unsigned long)params->base;
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params->dma_params_tx->maxburst = 4;
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params->dma_params_rx->maxburst = 6;
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ret = snd_soc_register_platform(&pdev->dev, &imx_soc_platform_fiq);
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if (ret)
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goto failed_register;
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return 0;
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failed_register:
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mxc_set_irq_fiq(ssi_irq, 0);
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release_fiq(&fh);
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return ret;
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}
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EXPORT_SYMBOL_GPL(imx_pcm_fiq_init);
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void imx_pcm_fiq_exit(struct platform_device *pdev)
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{
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snd_soc_unregister_platform(&pdev->dev);
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}
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EXPORT_SYMBOL_GPL(imx_pcm_fiq_exit);
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MODULE_LICENSE("GPL");
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