cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

route.c (3213B)

      1/*
      2 *  Route Plug-In
      3 *  Copyright (c) 2000 by Abramo Bagnara <abramo@alsa-project.org>
      4 *
      5 *
      6 *   This library is free software; you can redistribute it and/or modify
      7 *   it under the terms of the GNU Library General Public License as
      8 *   published by the Free Software Foundation; either version 2 of
      9 *   the License, or (at your option) any later version.
     10 *
     11 *   This program is distributed in the hope that it will be useful,
     12 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
     13 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     14 *   GNU Library General Public License for more details.
     15 *
     16 *   You should have received a copy of the GNU Library General Public
     17 *   License along with this library; if not, write to the Free Software
     18 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
     19 *
     20 */
     21
     22#include <linux/time.h>
     23#include <sound/core.h>
     24#include <sound/pcm.h>
     25#include "pcm_plugin.h"
     26
     27static void zero_areas(struct snd_pcm_plugin_channel *dvp, int ndsts,
     28		       snd_pcm_uframes_t frames, snd_pcm_format_t format)
     29{
     30	int dst = 0;
     31	for (; dst < ndsts; ++dst) {
     32		if (dvp->wanted)
     33			snd_pcm_area_silence(&dvp->area, 0, frames, format);
     34		dvp->enabled = 0;
     35		dvp++;
     36	}
     37}
     38
     39static inline void copy_area(const struct snd_pcm_plugin_channel *src_channel,
     40			     struct snd_pcm_plugin_channel *dst_channel,
     41			     snd_pcm_uframes_t frames, snd_pcm_format_t format)
     42{
     43	dst_channel->enabled = 1;
     44	snd_pcm_area_copy(&src_channel->area, 0, &dst_channel->area, 0, frames, format);
     45}
     46
     47static snd_pcm_sframes_t route_transfer(struct snd_pcm_plugin *plugin,
     48					const struct snd_pcm_plugin_channel *src_channels,
     49					struct snd_pcm_plugin_channel *dst_channels,
     50					snd_pcm_uframes_t frames)
     51{
     52	int nsrcs, ndsts, dst;
     53	struct snd_pcm_plugin_channel *dvp;
     54	snd_pcm_format_t format;
     55
     56	if (snd_BUG_ON(!plugin || !src_channels || !dst_channels))
     57		return -ENXIO;
     58	if (frames == 0)
     59		return 0;
     60	if (frames > dst_channels[0].frames)
     61		frames = dst_channels[0].frames;
     62
     63	nsrcs = plugin->src_format.channels;
     64	ndsts = plugin->dst_format.channels;
     65
     66	format = plugin->dst_format.format;
     67	dvp = dst_channels;
     68	if (nsrcs <= 1) {
     69		/* expand to all channels */
     70		for (dst = 0; dst < ndsts; ++dst) {
     71			copy_area(src_channels, dvp, frames, format);
     72			dvp++;
     73		}
     74		return frames;
     75	}
     76
     77	for (dst = 0; dst < ndsts && dst < nsrcs; ++dst) {
     78		copy_area(src_channels, dvp, frames, format);
     79		dvp++;
     80		src_channels++;
     81	}
     82	if (dst < ndsts)
     83		zero_areas(dvp, ndsts - dst, frames, format);
     84	return frames;
     85}
     86
     87int snd_pcm_plugin_build_route(struct snd_pcm_substream *plug,
     88			       struct snd_pcm_plugin_format *src_format,
     89			       struct snd_pcm_plugin_format *dst_format,
     90			       struct snd_pcm_plugin **r_plugin)
     91{
     92	struct snd_pcm_plugin *plugin;
     93	int err;
     94
     95	if (snd_BUG_ON(!r_plugin))
     96		return -ENXIO;
     97	*r_plugin = NULL;
     98	if (snd_BUG_ON(src_format->rate != dst_format->rate))
     99		return -ENXIO;
    100	if (snd_BUG_ON(src_format->format != dst_format->format))
    101		return -ENXIO;
    102
    103	err = snd_pcm_plugin_build(plug, "route conversion",
    104				   src_format, dst_format, 0, &plugin);
    105	if (err < 0)
    106		return err;
    107
    108	plugin->transfer = route_transfer;
    109	*r_plugin = plugin;
    110	return 0;
    111}