mirror of https://gitee.com/openkylin/linux.git
110 lines
2.6 KiB
C
110 lines
2.6 KiB
C
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/*
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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 <asm/atarihw.h>
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#include <asm/system.h>
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#include <asm/irq.h>
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#include <asm/pgtable.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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/* 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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