| /* |
| SDL - Simple DirectMedia Layer |
| Copyright (C) 1997-2004 Sam Lantinga |
| |
| This library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Library General Public |
| License as published by the Free Software Foundation; either |
| version 2 of the License, or (at your option) any later version. |
| |
| This library 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 |
| Library General Public License for more details. |
| |
| You should have received a copy of the GNU Library General Public |
| License along with this library; if not, write to the Free |
| Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| |
| Sam Lantinga |
| slouken@libsdl.org |
| */ |
| #include "SDL_config.h" |
| |
| /* Allow access to a raw mixing buffer */ |
| |
| #include <sys/types.h> |
| #include <signal.h> /* For kill() */ |
| #include <dlfcn.h> |
| #include <errno.h> |
| #include <string.h> |
| |
| #include "SDL_timer.h" |
| #include "SDL_audio.h" |
| #include "../SDL_audiomem.h" |
| #include "../SDL_audio_c.h" |
| #include "SDL_alsa_audio.h" |
| |
| |
| /* The tag name used by ALSA audio */ |
| #define DRIVER_NAME "alsa" |
| |
| /* The default ALSA audio driver */ |
| #define DEFAULT_DEVICE "default" |
| |
| static int (*ALSA_snd_pcm_open) |
| (snd_pcm_t **, const char *, snd_pcm_stream_t, int); |
| static int (*ALSA_snd_pcm_close)(snd_pcm_t * pcm); |
| static snd_pcm_sframes_t(*ALSA_snd_pcm_writei) |
| (snd_pcm_t *,const void *, snd_pcm_uframes_t); |
| static int (*ALSA_snd_pcm_resume)(snd_pcm_t *); |
| static int (*ALSA_snd_pcm_prepare)(snd_pcm_t *); |
| static int (*ALSA_snd_pcm_drain)(snd_pcm_t *); |
| static const char *(*ALSA_snd_strerror)(int); |
| static size_t(*ALSA_snd_pcm_hw_params_sizeof)(void); |
| static size_t(*ALSA_snd_pcm_sw_params_sizeof)(void); |
| static int (*ALSA_snd_pcm_hw_params_any)(snd_pcm_t *, snd_pcm_hw_params_t *); |
| static int (*ALSA_snd_pcm_hw_params_set_access) |
| (snd_pcm_t *, snd_pcm_hw_params_t *, snd_pcm_access_t); |
| static int (*ALSA_snd_pcm_hw_params_set_format) |
| (snd_pcm_t *, snd_pcm_hw_params_t *, snd_pcm_format_t); |
| static int (*ALSA_snd_pcm_hw_params_set_channels) |
| (snd_pcm_t *, snd_pcm_hw_params_t *, unsigned int); |
| static int (*ALSA_snd_pcm_hw_params_get_channels)(const snd_pcm_hw_params_t *); |
| static unsigned int (*ALSA_snd_pcm_hw_params_set_rate_near) |
| (snd_pcm_t *, snd_pcm_hw_params_t *, unsigned int, int *); |
| static snd_pcm_uframes_t (*ALSA_snd_pcm_hw_params_set_period_size_near) |
| (snd_pcm_t *, snd_pcm_hw_params_t *, snd_pcm_uframes_t, int *); |
| static snd_pcm_sframes_t (*ALSA_snd_pcm_hw_params_get_period_size) |
| (const snd_pcm_hw_params_t *); |
| static unsigned int (*ALSA_snd_pcm_hw_params_set_periods_near) |
| (snd_pcm_t *,snd_pcm_hw_params_t *, unsigned int, int *); |
| static int (*ALSA_snd_pcm_hw_params_get_periods)(snd_pcm_hw_params_t *); |
| static int (*ALSA_snd_pcm_hw_params)(snd_pcm_t *, snd_pcm_hw_params_t *); |
| static int (*ALSA_snd_pcm_sw_params_current)(snd_pcm_t*, snd_pcm_sw_params_t*); |
| static int (*ALSA_snd_pcm_sw_params_set_start_threshold) |
| (snd_pcm_t *, snd_pcm_sw_params_t *, snd_pcm_uframes_t); |
| static int (*ALSA_snd_pcm_sw_params_set_avail_min) |
| (snd_pcm_t *, snd_pcm_sw_params_t *, snd_pcm_uframes_t); |
| static int (*ALSA_snd_pcm_sw_params)(snd_pcm_t *, snd_pcm_sw_params_t *); |
| static int (*ALSA_snd_pcm_nonblock)(snd_pcm_t *, int); |
| #define snd_pcm_hw_params_sizeof ALSA_snd_pcm_hw_params_sizeof |
| #define snd_pcm_sw_params_sizeof ALSA_snd_pcm_sw_params_sizeof |
| |
| |
| #ifdef SDL_AUDIO_DRIVER_ALSA_DYNAMIC |
| |
| static const char *alsa_library = SDL_AUDIO_DRIVER_ALSA_DYNAMIC; |
| static void *alsa_handle = NULL; |
| |
| static int |
| load_alsa_sym(const char *fn, void **addr) |
| { |
| /* |
| * !!! FIXME: |
| * Eventually, this will deal with fallbacks, version changes, and |
| * missing symbols we can workaround. But for now, it doesn't. |
| */ |
| |
| #if HAVE_DLVSYM |
| *addr = dlvsym(alsa_handle, fn, "ALSA_0.9"); |
| if (*addr == NULL) |
| #endif |
| { |
| *addr = dlsym(alsa_handle, fn); |
| if (*addr == NULL) { |
| SDL_SetError("dlsym('%s') failed: %s", fn, strerror(errno)); |
| return 0; |
| } |
| } |
| |
| return 1; |
| } |
| |
| /* cast funcs to char* first, to please GCC's strict aliasing rules. */ |
| #define SDL_ALSA_SYM(x) \ |
| if (!load_alsa_sym(#x, (void **) (char *) &ALSA_##x)) return -1 |
| #else |
| #define SDL_ALSA_SYM(x) ALSA_##x = x |
| #endif |
| |
| static int load_alsa_syms(void) |
| { |
| SDL_ALSA_SYM(snd_pcm_open); |
| SDL_ALSA_SYM(snd_pcm_close); |
| SDL_ALSA_SYM(snd_pcm_writei); |
| SDL_ALSA_SYM(snd_pcm_resume); |
| SDL_ALSA_SYM(snd_pcm_prepare); |
| SDL_ALSA_SYM(snd_pcm_drain); |
| SDL_ALSA_SYM(snd_strerror); |
| SDL_ALSA_SYM(snd_pcm_hw_params_sizeof); |
| SDL_ALSA_SYM(snd_pcm_sw_params_sizeof); |
| SDL_ALSA_SYM(snd_pcm_hw_params_any); |
| SDL_ALSA_SYM(snd_pcm_hw_params_set_access); |
| SDL_ALSA_SYM(snd_pcm_hw_params_set_format); |
| SDL_ALSA_SYM(snd_pcm_hw_params_set_channels); |
| SDL_ALSA_SYM(snd_pcm_hw_params_get_channels); |
| SDL_ALSA_SYM(snd_pcm_hw_params_set_rate_near); |
| SDL_ALSA_SYM(snd_pcm_hw_params_set_period_size_near); |
| SDL_ALSA_SYM(snd_pcm_hw_params_get_period_size); |
| SDL_ALSA_SYM(snd_pcm_hw_params_set_periods_near); |
| SDL_ALSA_SYM(snd_pcm_hw_params_get_periods); |
| SDL_ALSA_SYM(snd_pcm_hw_params); |
| SDL_ALSA_SYM(snd_pcm_sw_params_current); |
| SDL_ALSA_SYM(snd_pcm_sw_params_set_start_threshold); |
| SDL_ALSA_SYM(snd_pcm_sw_params_set_avail_min); |
| SDL_ALSA_SYM(snd_pcm_sw_params); |
| SDL_ALSA_SYM(snd_pcm_nonblock); |
| return 0; |
| } |
| #undef SDL_ALSA_SYM |
| |
| #ifdef SDL_AUDIO_DRIVER_ALSA_DYNAMIC |
| |
| static void |
| UnloadALSALibrary(void) |
| { |
| if (alsa_handle != NULL) { |
| dlclose(alsa_handle); |
| alsa_handle = NULL; |
| } |
| } |
| |
| static int |
| LoadALSALibrary(void) |
| { |
| int retval = 0; |
| if (alsa_handle == NULL) { |
| alsa_handle = dlopen(alsa_library, RTLD_NOW); |
| if (alsa_handle == NULL) { |
| retval = -1; |
| SDL_SetError("ALSA: dlopen('%s') failed: %s\n", |
| alsa_library, strerror(errno)); |
| } else { |
| retval = load_alsa_syms(); |
| if (retval < 0) { |
| UnloadALSALibrary(); |
| } |
| } |
| } |
| return retval; |
| } |
| |
| #else |
| |
| static void |
| UnloadALSALibrary(void) |
| { |
| } |
| |
| static int |
| LoadALSALibrary(void) |
| { |
| load_alsa_syms(); |
| return 0; |
| } |
| |
| #endif /* SDL_AUDIO_DRIVER_ALSA_DYNAMIC */ |
| |
| static const char * |
| get_audio_device(int channels) |
| { |
| const char *device; |
| |
| device = SDL_getenv("AUDIODEV"); /* Is there a standard variable name? */ |
| if (device == NULL) { |
| if (channels == 6) |
| device = "surround51"; |
| else if (channels == 4) |
| device = "surround40"; |
| else |
| device = DEFAULT_DEVICE; |
| } |
| return device; |
| } |
| |
| |
| /* This function waits until it is possible to write a full sound buffer */ |
| static void |
| ALSA_WaitDevice(_THIS) |
| { |
| /* Check to see if the thread-parent process is still alive */ |
| { |
| static int cnt = 0; |
| /* Note that this only works with thread implementations |
| that use a different process id for each thread. |
| */ |
| /* Check every 10 loops */ |
| if (this->hidden->parent && (((++cnt) % 10) == 0)) { |
| if (kill(this->hidden->parent, 0) < 0) { |
| this->enabled = 0; |
| } |
| } |
| } |
| } |
| |
| |
| /* !!! FIXME: is there a channel swizzler in alsalib instead? */ |
| /* |
| * http://bugzilla.libsdl.org/show_bug.cgi?id=110 |
| * "For Linux ALSA, this is FL-FR-RL-RR-C-LFE |
| * and for Windows DirectX [and CoreAudio], this is FL-FR-C-LFE-RL-RR" |
| */ |
| #define SWIZ6(T) \ |
| T *ptr = (T *) this->hidden->mixbuf; \ |
| const Uint32 count = (this->spec.samples / 6); \ |
| Uint32 i; \ |
| for (i = 0; i < count; i++, ptr += 6) { \ |
| T tmp; \ |
| tmp = ptr[2]; ptr[2] = ptr[4]; ptr[4] = tmp; \ |
| tmp = ptr[3]; ptr[3] = ptr[5]; ptr[5] = tmp; \ |
| } |
| |
| static __inline__ void |
| swizzle_alsa_channels_6_64bit(_THIS) |
| { |
| SWIZ6(Uint64); |
| } |
| static __inline__ void |
| swizzle_alsa_channels_6_32bit(_THIS) |
| { |
| SWIZ6(Uint32); |
| } |
| static __inline__ void |
| swizzle_alsa_channels_6_16bit(_THIS) |
| { |
| SWIZ6(Uint16); |
| } |
| static __inline__ void |
| swizzle_alsa_channels_6_8bit(_THIS) |
| { |
| SWIZ6(Uint8); |
| } |
| |
| #undef SWIZ6 |
| |
| |
| /* |
| * Called right before feeding this->hidden->mixbuf to the hardware. Swizzle |
| * channels from Windows/Mac order to the format alsalib will want. |
| */ |
| static __inline__ void |
| swizzle_alsa_channels(_THIS) |
| { |
| if (this->spec.channels == 6) { |
| const Uint16 fmtsize = (this->spec.format & 0xFF); /* bits/channel. */ |
| if (fmtsize == 16) |
| swizzle_alsa_channels_6_16bit(this); |
| else if (fmtsize == 8) |
| swizzle_alsa_channels_6_8bit(this); |
| else if (fmtsize == 32) |
| swizzle_alsa_channels_6_32bit(this); |
| else if (fmtsize == 64) |
| swizzle_alsa_channels_6_64bit(this); |
| } |
| |
| /* !!! FIXME: update this for 7.1 if needed, later. */ |
| } |
| |
| |
| static void |
| ALSA_PlayDevice(_THIS) |
| { |
| int status; |
| int sample_len; |
| signed short *sample_buf; |
| |
| swizzle_alsa_channels(this); |
| |
| sample_len = this->spec.samples; |
| sample_buf = (signed short *) this->hidden->mixbuf; |
| |
| while (sample_len > 0) { |
| status = ALSA_snd_pcm_writei(this->hidden->pcm_handle, |
| sample_buf, sample_len); |
| |
| if (status < 0) { |
| if (status == -EAGAIN) { |
| SDL_Delay(1); |
| continue; |
| } |
| if (status == -ESTRPIPE) { |
| do { |
| SDL_Delay(1); |
| status = ALSA_snd_pcm_resume(this->hidden->pcm_handle); |
| } while (status == -EAGAIN); |
| } |
| if (status < 0) { |
| status = ALSA_snd_pcm_prepare(this->hidden->pcm_handle); |
| } |
| if (status < 0) { |
| /* Hmm, not much we can do - abort */ |
| this->enabled = 0; |
| return; |
| } |
| continue; |
| } |
| sample_buf += status * this->spec.channels; |
| sample_len -= status; |
| } |
| } |
| |
| static Uint8 * |
| ALSA_GetDeviceBuf(_THIS) |
| { |
| return (this->hidden->mixbuf); |
| } |
| |
| static void |
| ALSA_CloseDevice(_THIS) |
| { |
| if (this->hidden != NULL) { |
| if (this->hidden->mixbuf != NULL) { |
| SDL_FreeAudioMem(this->hidden->mixbuf); |
| this->hidden->mixbuf = NULL; |
| } |
| if (this->hidden->pcm_handle) { |
| ALSA_snd_pcm_drain(this->hidden->pcm_handle); |
| ALSA_snd_pcm_close(this->hidden->pcm_handle); |
| this->hidden->pcm_handle = NULL; |
| } |
| SDL_free(this->hidden); |
| this->hidden = NULL; |
| } |
| } |
| |
| static int |
| ALSA_OpenDevice(_THIS, const char *devname, int iscapture) |
| { |
| int status = 0; |
| snd_pcm_t *pcm_handle = NULL; |
| snd_pcm_hw_params_t *hwparams = NULL; |
| snd_pcm_sw_params_t *swparams = NULL; |
| snd_pcm_format_t format = 0; |
| snd_pcm_uframes_t frames = 0; |
| SDL_AudioFormat test_format = 0; |
| |
| /* Initialize all variables that we clean on shutdown */ |
| this->hidden = (struct SDL_PrivateAudioData *) |
| SDL_malloc((sizeof *this->hidden)); |
| if (this->hidden == NULL) { |
| SDL_OutOfMemory(); |
| return 0; |
| } |
| SDL_memset(this->hidden, 0, (sizeof *this->hidden)); |
| |
| /* Open the audio device */ |
| /* Name of device should depend on # channels in spec */ |
| status = ALSA_snd_pcm_open(&pcm_handle, |
| get_audio_device(this->spec.channels), |
| SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK); |
| |
| if (status < 0) { |
| ALSA_CloseDevice(this); |
| SDL_SetError("ALSA: Couldn't open audio device: %s", |
| ALSA_snd_strerror(status)); |
| return 0; |
| } |
| |
| this->hidden->pcm_handle = pcm_handle; |
| |
| /* Figure out what the hardware is capable of */ |
| snd_pcm_hw_params_alloca(&hwparams); |
| status = ALSA_snd_pcm_hw_params_any(pcm_handle, hwparams); |
| if (status < 0) { |
| ALSA_CloseDevice(this); |
| SDL_SetError("ALSA: Couldn't get hardware config: %s", |
| ALSA_snd_strerror(status)); |
| return 0; |
| } |
| |
| /* SDL only uses interleaved sample output */ |
| status = ALSA_snd_pcm_hw_params_set_access(pcm_handle, hwparams, |
| SND_PCM_ACCESS_RW_INTERLEAVED); |
| if (status < 0) { |
| ALSA_CloseDevice(this); |
| SDL_SetError("ALSA: Couldn't set interleaved access: %s", |
| ALSA_snd_strerror(status)); |
| return 0; |
| } |
| |
| /* Try for a closest match on audio format */ |
| status = -1; |
| for (test_format = SDL_FirstAudioFormat(this->spec.format); |
| test_format && (status < 0);) { |
| status = 0; /* if we can't support a format, it'll become -1. */ |
| switch (test_format) { |
| case AUDIO_U8: |
| format = SND_PCM_FORMAT_U8; |
| break; |
| case AUDIO_S8: |
| format = SND_PCM_FORMAT_S8; |
| break; |
| case AUDIO_S16LSB: |
| format = SND_PCM_FORMAT_S16_LE; |
| break; |
| case AUDIO_S16MSB: |
| format = SND_PCM_FORMAT_S16_BE; |
| break; |
| case AUDIO_U16LSB: |
| format = SND_PCM_FORMAT_U16_LE; |
| break; |
| case AUDIO_U16MSB: |
| format = SND_PCM_FORMAT_U16_BE; |
| break; |
| case AUDIO_S32LSB: |
| format = SND_PCM_FORMAT_S32_LE; |
| break; |
| case AUDIO_S32MSB: |
| format = SND_PCM_FORMAT_S32_BE; |
| break; |
| case AUDIO_F32LSB: |
| format = SND_PCM_FORMAT_FLOAT_LE; |
| break; |
| case AUDIO_F32MSB: |
| format = SND_PCM_FORMAT_FLOAT_BE; |
| break; |
| default: |
| status = -1; |
| break; |
| } |
| if (status >= 0) { |
| status = ALSA_snd_pcm_hw_params_set_format(pcm_handle, |
| hwparams, format); |
| } |
| if (status < 0) { |
| test_format = SDL_NextAudioFormat(); |
| } |
| } |
| if (status < 0) { |
| ALSA_CloseDevice(this); |
| SDL_SetError("ALSA: Couldn't find any hardware audio formats"); |
| return 0; |
| } |
| this->spec.format = test_format; |
| |
| /* Set the number of channels */ |
| status = ALSA_snd_pcm_hw_params_set_channels(pcm_handle, hwparams, |
| this->spec.channels); |
| if (status < 0) { |
| status = ALSA_snd_pcm_hw_params_get_channels(hwparams); |
| if ((status <= 0) || (status > 2)) { |
| ALSA_CloseDevice(this); |
| SDL_SetError("ALSA: Couldn't set audio channels"); |
| return 0; |
| } |
| this->spec.channels = status; |
| } |
| |
| /* Set the audio rate */ |
| status = ALSA_snd_pcm_hw_params_set_rate_near(pcm_handle, hwparams, |
| this->spec.freq, NULL); |
| if (status < 0) { |
| ALSA_CloseDevice(this); |
| SDL_SetError("ALSA: Couldn't set audio frequency: %s", |
| ALSA_snd_strerror(status)); |
| return 0; |
| } |
| this->spec.freq = status; |
| |
| /* Set the buffer size, in samples */ |
| frames = this->spec.samples; |
| frames = ALSA_snd_pcm_hw_params_set_period_size_near(pcm_handle, hwparams, |
| frames, NULL); |
| this->spec.samples = frames; |
| ALSA_snd_pcm_hw_params_set_periods_near(pcm_handle, hwparams, 2, NULL); |
| |
| /* "set" the hardware with the desired parameters */ |
| status = ALSA_snd_pcm_hw_params(pcm_handle, hwparams); |
| if (status < 0) { |
| ALSA_CloseDevice(this); |
| SDL_SetError("ALSA: Couldn't set hardware audio parameters: %s", |
| ALSA_snd_strerror(status)); |
| return 0; |
| } |
| |
| #if AUDIO_DEBUG |
| { |
| snd_pcm_sframes_t bufsize; |
| int fragments; |
| bufsize = ALSA_snd_pcm_hw_params_get_period_size(hwparams); |
| fragments = ALSA_snd_pcm_hw_params_get_periods(hwparams); |
| fprintf(stderr,"ALSA: bufsize = %ld, fragments = %d\n",bufsize,fragments); |
| } |
| #endif |
| |
| /* Set the software parameters */ |
| snd_pcm_sw_params_alloca(&swparams); |
| status = ALSA_snd_pcm_sw_params_current(pcm_handle, swparams); |
| if (status < 0) { |
| ALSA_CloseDevice(this); |
| SDL_SetError("ALSA: Couldn't get software config: %s", |
| ALSA_snd_strerror(status)); |
| return 0; |
| } |
| status = ALSA_snd_pcm_sw_params_set_start_threshold(pcm_handle,swparams,0); |
| if (status < 0) { |
| ALSA_CloseDevice(this); |
| SDL_SetError("ALSA: Couldn't set start threshold: %s", |
| ALSA_snd_strerror(status)); |
| return 0; |
| } |
| status = ALSA_snd_pcm_sw_params_set_avail_min(pcm_handle, swparams, frames); |
| if (status < 0) { |
| ALSA_CloseDevice(this); |
| SDL_SetError("Couldn't set avail min: %s", ALSA_snd_strerror(status)); |
| return 0; |
| } |
| status = ALSA_snd_pcm_sw_params(pcm_handle, swparams); |
| if (status < 0) { |
| ALSA_CloseDevice(this); |
| SDL_SetError("Couldn't set software audio parameters: %s", |
| ALSA_snd_strerror(status)); |
| return 0; |
| } |
| |
| /* Calculate the final parameters for this audio specification */ |
| SDL_CalculateAudioSpec(&this->spec); |
| |
| /* Allocate mixing buffer */ |
| this->hidden->mixlen = this->spec.size; |
| this->hidden->mixbuf = (Uint8 *) SDL_AllocAudioMem(this->hidden->mixlen); |
| if (this->hidden->mixbuf == NULL) { |
| ALSA_CloseDevice(this); |
| SDL_OutOfMemory(); |
| return 0; |
| } |
| SDL_memset(this->hidden->mixbuf, this->spec.silence, this->spec.size); |
| |
| /* Get the parent process id (we're the parent of the audio thread) */ |
| this->hidden->parent = getpid(); |
| |
| /* Switch to blocking mode for playback */ |
| ALSA_snd_pcm_nonblock(pcm_handle, 0); |
| |
| /* We're ready to rock and roll. :-) */ |
| return 1; |
| } |
| |
| static void |
| ALSA_Deinitialize(void) |
| { |
| UnloadALSALibrary(); |
| } |
| |
| static int |
| ALSA_Init(SDL_AudioDriverImpl *impl) |
| { |
| if (LoadALSALibrary() < 0) { |
| return 0; |
| } |
| |
| /* Set the function pointers */ |
| impl->OpenDevice = ALSA_OpenDevice; |
| impl->WaitDevice = ALSA_WaitDevice; |
| impl->GetDeviceBuf = ALSA_GetDeviceBuf; |
| impl->PlayDevice = ALSA_PlayDevice; |
| impl->CloseDevice = ALSA_CloseDevice; |
| impl->Deinitialize = ALSA_Deinitialize; |
| impl->OnlyHasDefaultOutputDevice = 1; /* !!! FIXME: Add device enum! */ |
| |
| return 1; |
| } |
| |
| |
| AudioBootStrap ALSA_bootstrap = { |
| DRIVER_NAME, "ALSA 0.9 PCM audio", ALSA_Init, 0 |
| }; |
| |
| /* vi: set ts=4 sw=4 expandtab: */ |
