pulseaudio/src/pulsecore/cpu-arm.c

/***
  This file is part of PulseAudio.

  Copyright 2004-2006 Lennart Poettering
  Copyright 2009 Wim Taymans <wim.taymans@collabora.co.uk> 

  PulseAudio is free software; you can redistribute it and/or modify
  it under the terms of the GNU Lesser General Public License as published
  by the Free Software Foundation; either version 2.1 of the License,
  or (at your option) any later version.

  PulseAudio 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 Lesser General Public License
  along with PulseAudio; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  USA.
***/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdint.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#include <pulse/xmalloc.h>
#include <pulsecore/log.h>

#include "cpu-arm.h"

#if defined (__arm__) && defined (__linux__)

#define MAX_BUFFER  4096
static char *
get_cpuinfo_line (char *cpuinfo, const char *tag) {
    char *line, *end, *colon;

    if (!(line = strstr (cpuinfo, tag)))
        return NULL;

    if (!(end = strchr (line, '\n')))
        return NULL;

    if (!(colon = strchr (line, ':')))
        return NULL;

    if (++colon >= end)
        return NULL;

    return pa_xstrndup (colon, end - colon);
}

static char *get_cpuinfo(void) {
    char *cpuinfo;
    int n, fd;

    if (!(cpuinfo = malloc(MAX_BUFFER)))
         return NULL;

    if ((fd = open("/proc/cpuinfo", O_RDONLY)) < 0) {
        free (cpuinfo);
        return NULL;
    }

    if ((n = read(fd, cpuinfo, MAX_BUFFER-1)) < 0) {
        free (cpuinfo);
        close (fd);
        return NULL;
    }
    cpuinfo[n] = 0;
    close (fd);

    return cpuinfo;
}
#endif /* defined (__arm__) && defined (__linux__) */

void pa_cpu_init_arm (void) {
#if defined (__arm__)
#if defined (__linux__)
    char *cpuinfo, *line;
    int arch;
    pa_cpu_arm_flag_t flags = 0;

    /* We need to read the CPU flags from /proc/cpuinfo because there is no user
     * space support to get the CPU features. This only works on linux AFAIK. */
    if (!(cpuinfo = get_cpuinfo ())) {
        pa_log ("Can't read cpuinfo");
        return;
    }

    /* get the CPU architecture */
    if ((line = get_cpuinfo_line (cpuinfo, "CPU architecture"))) {
        arch = strtoul (line, NULL, 0);
        if (arch >= 6)
            flags |= PA_CPU_ARM_V6;
        if (arch >= 7)
            flags |= PA_CPU_ARM_V7;

        free (line);
    }
    /* get the CPU features */
    if ((line = get_cpuinfo_line (cpuinfo, "Features"))) {
        char *state = NULL, *current;

        while ((current = pa_split_spaces (line, &state))) {
            if (!strcmp (current, "vfp"))
                flags |= PA_CPU_ARM_VFP;
            else if (!strcmp (current, "edsp"))
                flags |= PA_CPU_ARM_EDSP;
            else if (!strcmp (current, "neon"))
                flags |= PA_CPU_ARM_NEON;
            else if (!strcmp (current, "vfpv3"))
                flags |= PA_CPU_ARM_VFPV3;

            free (current);
        }
    }
    free (cpuinfo);

    pa_log_info ("CPU flags: %s%s%s%s%s%s",
          (flags & PA_CPU_ARM_V6) ? "V6 " : "",
          (flags & PA_CPU_ARM_V7) ? "V7 " : "",
          (flags & PA_CPU_ARM_VFP) ? "VFP " : "",
          (flags & PA_CPU_ARM_EDSP) ? "EDSP " : "",
          (flags & PA_CPU_ARM_NEON) ? "NEON " : "",
          (flags & PA_CPU_ARM_VFPV3) ? "VFPV3 " : "");
#else /* defined (__linux__) */
    pa_log ("ARM cpu features not yet supported on this OS");
#endif /* defined (__linux__) */

    if (flags & PA_CPU_ARM_V6)
        pa_volume_func_init_arm (flags);
#endif /* defined (__arm__) */
}