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