?? sound.c
字號(hào):
#include <linux/module.h>#include <rtl_fifo.h>#include <asm/rt_irq.h>#include <linux/rt_time.h>#include <linux/mc146818rtc.h>#include <linux/cons.h>static int filter(int x){ static int oldx; int ret; if (x & 0x80) { x = 382 - x; } ret = x > oldx; oldx = x; return ret; }void intr_handler(void) { char data; char temp; (void) CMOS_READ(RTC_REG_C); /* clear IRQ */ if (rtf_get(0, &data, 1) > 0) { data = filter(data);/* if (data) conpr("1"); else conpr("0"); */ temp = inb(0x61); temp &= 0xfc; if (data) { temp |= 3; } outb(temp,0x61); }}char save_cmos_A;char save_cmos_B;int init_module(void){ char ctemp; if (!I8253_channel2_free()) { conpr("RTLinux sound: can't use channel 2; bailing out\n"); return -1; } rtf_create(0, 4000); /* this is just to ensure that the output of the counter is 1 */ outb_p(0xb0, 0x43); /* binary, mode 0, LSB/MSB, ch 2 */ outb_p(0x1, 0x42); outb_p(0x0, 0x42); request_RTirq(8, intr_handler); /* program the RTC to interrupt at 8192 Hz */ save_cmos_A = CMOS_READ(RTC_REG_A); save_cmos_B = CMOS_READ(RTC_REG_B); CMOS_WRITE(0x23, RTC_REG_A); /* 32kHz Time Base, 8192 Hz interrupt frequency */ ctemp = CMOS_READ(RTC_REG_B); ctemp &= 0x8f; /* Clear */ ctemp |= 0x40; /* Periodic interrupt enable */ CMOS_WRITE(ctemp, RTC_REG_B); (void) CMOS_READ(RTC_REG_C); return 0;} void cleanup_module(void){ rtf_destroy(0); outb_p(0xb6, 0x43); /* restore the original mode */ CMOS_WRITE(save_cmos_A, RTC_REG_A); CMOS_WRITE(save_cmos_B, RTC_REG_B); free_RTirq(8);}?? 快捷鍵說明
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