diff options
Diffstat (limited to 'arch/m68k/atari/atasound.c')
-rw-r--r-- | arch/m68k/atari/atasound.c | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/arch/m68k/atari/atasound.c b/arch/m68k/atari/atasound.c new file mode 100644 index 0000000000..a8724d998c --- /dev/null +++ b/arch/m68k/atari/atasound.c @@ -0,0 +1,109 @@ +/* + * linux/arch/m68k/atari/atasound.c + * + * ++Geert: Moved almost all stuff to linux/drivers/sound/ + * + * The author of atari_nosound, atari_mksound and atari_microwire_cmd is + * unknown. (++roman: That's me... :-) + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file COPYING in the main directory of this archive + * for more details. + * + * 1998-05-31 ++andreas: atari_mksound rewritten to always use the envelope, + * no timer, atari_nosound removed. + * + */ + + +#include <linux/sched.h> +#include <linux/timer.h> +#include <linux/major.h> +#include <linux/fcntl.h> +#include <linux/errno.h> +#include <linux/mm.h> +#include <linux/module.h> + +#include <asm/atarihw.h> +#include <asm/irq.h> +#include <asm/atariints.h> + + +/* + * stuff from the old atasound.c + */ + +void atari_microwire_cmd (int cmd) +{ + tt_microwire.mask = 0x7ff; + tt_microwire.data = MW_LM1992_ADDR | cmd; + + /* Busy wait for data being completely sent :-( */ + while( tt_microwire.mask != 0x7ff) + ; +} +EXPORT_SYMBOL(atari_microwire_cmd); + + +/* PSG base frequency */ +#define PSG_FREQ 125000 +/* PSG envelope base frequency times 10 */ +#define PSG_ENV_FREQ_10 78125 + +void atari_mksound (unsigned int hz, unsigned int ticks) +{ + /* Generates sound of some frequency for some number of clock + ticks. */ + unsigned long flags; + unsigned char tmp; + int period; + + local_irq_save(flags); + + + /* Disable generator A in mixer control. */ + sound_ym.rd_data_reg_sel = 7; + tmp = sound_ym.rd_data_reg_sel; + tmp |= 011; + sound_ym.wd_data = tmp; + + if (hz) { + /* Convert from frequency value to PSG period value (base + frequency 125 kHz). */ + + period = PSG_FREQ / hz; + + if (period > 0xfff) period = 0xfff; + + /* Set generator A frequency to hz. */ + sound_ym.rd_data_reg_sel = 0; + sound_ym.wd_data = period & 0xff; + sound_ym.rd_data_reg_sel = 1; + sound_ym.wd_data = (period >> 8) & 0xf; + if (ticks) { + /* Set length of envelope (max 8 sec). */ + int length = (ticks * PSG_ENV_FREQ_10) / HZ / 10; + + if (length > 0xffff) length = 0xffff; + sound_ym.rd_data_reg_sel = 11; + sound_ym.wd_data = length & 0xff; + sound_ym.rd_data_reg_sel = 12; + sound_ym.wd_data = length >> 8; + /* Envelope form: max -> min single. */ + sound_ym.rd_data_reg_sel = 13; + sound_ym.wd_data = 0; + /* Use envelope for generator A. */ + sound_ym.rd_data_reg_sel = 8; + sound_ym.wd_data = 0x10; + } else { + /* Set generator A level to maximum, no envelope. */ + sound_ym.rd_data_reg_sel = 8; + sound_ym.wd_data = 15; + } + /* Turn on generator A in mixer control. */ + sound_ym.rd_data_reg_sel = 7; + tmp &= ~1; + sound_ym.wd_data = tmp; + } + local_irq_restore(flags); +} |