1 /* 2 * linux/arch/m68k/atari/atasound.c 3 * 4 * ++Geert: Moved almost all stuff to linux/drivers/sound/ 5 * 6 * The author of atari_nosound, atari_mksound and atari_microwire_cmd is 7 * unknown. (++roman: That's me... :-) 8 * 9 * This file is subject to the terms and conditions of the GNU General Public 10 * License. See the file COPYING in the main directory of this archive 11 * for more details. 12 * 13 * 1998-05-31 ++andreas: atari_mksound rewritten to always use the envelope, 14 * no timer, atari_nosound removed. 15 * 16 */ 17 18 19 #include <linux/sched.h> 20 #include <linux/timer.h> 21 #include <linux/major.h> 22 #include <linux/fcntl.h> 23 #include <linux/errno.h> 24 #include <linux/mm.h> 25 #include <linux/module.h> 26 27 #include <asm/atarihw.h> 28 #include <asm/irq.h> 29 #include <asm/atariints.h> 30 31 32 /* 33 * stuff from the old atasound.c 34 */ 35 36 void atari_microwire_cmd (int cmd) 37 { 38 tt_microwire.mask = 0x7ff; 39 tt_microwire.data = MW_LM1992_ADDR | cmd; 40 41 /* Busy wait for data being completely sent :-( */ 42 while( tt_microwire.mask != 0x7ff) 43 ; 44 } 45 EXPORT_SYMBOL(atari_microwire_cmd); 46 47 48 /* PSG base frequency */ 49 #define PSG_FREQ 125000 50 /* PSG envelope base frequency times 10 */ 51 #define PSG_ENV_FREQ_10 78125 52 53 void atari_mksound (unsigned int hz, unsigned int ticks) 54 { 55 /* Generates sound of some frequency for some number of clock 56 ticks. */ 57 unsigned long flags; 58 unsigned char tmp; 59 int period; 60 61 local_irq_save(flags); 62 63 64 /* Disable generator A in mixer control. */ 65 sound_ym.rd_data_reg_sel = 7; 66 tmp = sound_ym.rd_data_reg_sel; 67 tmp |= 011; 68 sound_ym.wd_data = tmp; 69 70 if (hz) { 71 /* Convert from frequency value to PSG period value (base 72 frequency 125 kHz). */ 73 74 period = PSG_FREQ / hz; 75 76 if (period > 0xfff) period = 0xfff; 77 78 /* Set generator A frequency to hz. */ 79 sound_ym.rd_data_reg_sel = 0; 80 sound_ym.wd_data = period & 0xff; 81 sound_ym.rd_data_reg_sel = 1; 82 sound_ym.wd_data = (period >> 8) & 0xf; 83 if (ticks) { 84 /* Set length of envelope (max 8 sec). */ 85 int length = (ticks * PSG_ENV_FREQ_10) / HZ / 10; 86 87 if (length > 0xffff) length = 0xffff; 88 sound_ym.rd_data_reg_sel = 11; 89 sound_ym.wd_data = length & 0xff; 90 sound_ym.rd_data_reg_sel = 12; 91 sound_ym.wd_data = length >> 8; 92 /* Envelope form: max -> min single. */ 93 sound_ym.rd_data_reg_sel = 13; 94 sound_ym.wd_data = 0; 95 /* Use envelope for generator A. */ 96 sound_ym.rd_data_reg_sel = 8; 97 sound_ym.wd_data = 0x10; 98 } else { 99 /* Set generator A level to maximum, no envelope. */ 100 sound_ym.rd_data_reg_sel = 8; 101 sound_ym.wd_data = 15; 102 } 103 /* Turn on generator A in mixer control. */ 104 sound_ym.rd_data_reg_sel = 7; 105 tmp &= ~1; 106 sound_ym.wd_data = tmp; 107 } 108 local_irq_restore(flags); 109 } 110