1 // 16bit code to handle system clocks.
3 // Copyright (C) 2008-2010 Kevin O'Connor <kevin@koconnor.net>
4 // Copyright (C) 2002 MandrakeSoft S.A.
6 // This file may be distributed under the terms of the GNU LGPLv3 license.
8 #include "biosvar.h" // SET_BDA
9 #include "util.h" // debug_enter
10 #include "disk.h" // floppy_tick
11 #include "cmos.h" // inb_cmos
12 #include "pic.h" // eoi_pic1
13 #include "bregs.h" // struct bregs
14 #include "biosvar.h" // GET_GLOBAL
15 #include "usb-hid.h" // usb_check_event
18 #define RTC_A_UIP 0x80
20 #define RTC_B_SET 0x80
21 #define RTC_B_PIE 0x40
22 #define RTC_B_AIE 0x20
23 #define RTC_B_UIE 0x10
24 #define RTC_B_BIN 0x04
25 #define RTC_B_24HR 0x02
26 #define RTC_B_DSE 0x01
29 // Bits for PORT_PS2_CTRLB
30 #define PPCB_T2GATE (1<<0)
31 #define PPCB_SPKR (1<<1)
32 #define PPCB_T2OUT (1<<5)
34 // Bits for PORT_PIT_MODE
35 #define PM_SEL_TIMER0 (0<<6)
36 #define PM_SEL_TIMER1 (1<<6)
37 #define PM_SEL_TIMER2 (2<<6)
38 #define PM_SEL_READBACK (3<<6)
39 #define PM_ACCESS_LATCH (0<<4)
40 #define PM_ACCESS_LOBYTE (1<<4)
41 #define PM_ACCESS_HIBYTE (2<<4)
42 #define PM_ACCESS_WORD (3<<4)
43 #define PM_MODE0 (0<<1)
44 #define PM_MODE1 (1<<1)
45 #define PM_MODE2 (2<<1)
46 #define PM_MODE3 (3<<1)
47 #define PM_MODE4 (4<<1)
48 #define PM_MODE5 (5<<1)
49 #define PM_CNT_BINARY (0<<0)
50 #define PM_CNT_BCD (1<<0)
53 /****************************************************************
55 ****************************************************************/
57 #define CALIBRATE_COUNT 0x800 // Approx 1.7ms
59 u32 cpu_khz VAR16VISIBLE;
65 u8 orig = inb(PORT_PS2_CTRLB);
66 outb((orig & ~PPCB_SPKR) | PPCB_T2GATE, PORT_PS2_CTRLB);
67 /* binary, mode 0, LSB/MSB, Ch 2 */
68 outb(PM_SEL_TIMER2|PM_ACCESS_WORD|PM_MODE0|PM_CNT_BINARY, PORT_PIT_MODE);
70 outb(CALIBRATE_COUNT & 0xFF, PORT_PIT_COUNTER2);
72 outb(CALIBRATE_COUNT >> 8, PORT_PIT_COUNTER2);
74 u64 start = rdtscll();
75 while ((inb(PORT_PS2_CTRLB) & PPCB_T2OUT) == 0)
79 // Restore PORT_PS2_CTRLB
80 outb(orig, PORT_PS2_CTRLB);
82 // Store calibrated cpu khz.
83 u64 diff = end - start;
84 dprintf(6, "tsc calibrate start=%u end=%u diff=%u\n"
85 , (u32)start, (u32)end, (u32)diff);
86 u32 hz = diff * PIT_TICK_RATE / CALIBRATE_COUNT;
87 SET_GLOBAL(cpu_khz, hz / 1000);
89 dprintf(1, "CPU Mhz=%u\n", hz / 1000000);
95 u64 start = rdtscll();
96 u64 end = start + diff;
97 while (!check_tsc(end))
104 u64 start = rdtscll();
105 u64 end = start + diff;
106 while (!check_tsc(end))
110 void ndelay(u32 count) {
111 tscdelay(count * GET_GLOBAL(cpu_khz) / 1000000);
113 void udelay(u32 count) {
114 tscdelay(count * GET_GLOBAL(cpu_khz) / 1000);
116 void mdelay(u32 count) {
117 tscdelay(count * GET_GLOBAL(cpu_khz));
120 void nsleep(u32 count) {
121 tscsleep(count * GET_GLOBAL(cpu_khz) / 1000000);
123 void usleep(u32 count) {
124 tscsleep(count * GET_GLOBAL(cpu_khz) / 1000);
126 void msleep(u32 count) {
127 tscsleep(count * GET_GLOBAL(cpu_khz));
130 // Return the TSC value that is 'msecs' time in the future.
132 calc_future_tsc(u32 msecs)
134 u32 khz = GET_GLOBAL(cpu_khz);
135 return rdtscll() + ((u64)khz * msecs);
138 calc_future_tsc_usec(u32 usecs)
140 u32 khz = GET_GLOBAL(cpu_khz);
141 return rdtscll() + ((u64)(khz/1000) * usecs);
145 /****************************************************************
147 ****************************************************************/
152 // This function checks to see if the update-in-progress bit
153 // is set in CMOS Status Register A. If not, it returns 0.
154 // If it is set, it tries to wait until there is a transition
155 // to 0, and will return 0 if such a transition occurs. A -1
156 // is returned only after timing out. The maximum period
157 // that this bit should be set is constrained to (1984+244)
158 // useconds, but we wait for longer just to be sure.
160 if ((inb_cmos(CMOS_STATUS_A) & RTC_A_UIP) == 0)
162 u64 end = calc_future_tsc(15);
164 if ((inb_cmos(CMOS_STATUS_A) & RTC_A_UIP) == 0)
167 // update-in-progress never transitioned to 0
176 // timer0: binary count, 16bit count, mode 2
177 outb(PM_SEL_TIMER0|PM_ACCESS_WORD|PM_MODE2|PM_CNT_BINARY, PORT_PIT_MODE);
178 // maximum count of 0000H = 18.2Hz
179 outb(0x0, PORT_PIT_COUNTER0);
180 outb(0x0, PORT_PIT_COUNTER0);
186 outb_cmos(0x26, CMOS_STATUS_A); // 32,768Khz src, 976.5625us updates
187 u8 regB = inb_cmos(CMOS_STATUS_B);
188 outb_cmos((regB & RTC_B_DSE) | RTC_B_24HR, CMOS_STATUS_B);
189 inb_cmos(CMOS_STATUS_C);
190 inb_cmos(CMOS_STATUS_D);
196 return (val & 0xf) + ((val >> 4) * 10);
202 dprintf(3, "init timer\n");
208 u32 seconds = bcd2bin(inb_cmos(CMOS_RTC_SECONDS));
209 u32 minutes = bcd2bin(inb_cmos(CMOS_RTC_MINUTES));
210 u32 hours = bcd2bin(inb_cmos(CMOS_RTC_HOURS));
211 u32 ticks = (hours * 60 + minutes) * 60 + seconds;
212 ticks = ((u64)ticks * PIT_TICK_RATE) / PIT_TICK_INTERVAL;
213 SET_BDA(timer_counter, ticks);
215 enable_hwirq(0, FUNC16(entry_08));
216 enable_hwirq(8, FUNC16(entry_70));
220 /****************************************************************
221 * Standard clock functions
222 ****************************************************************/
224 #define TICKS_PER_DAY (u32)((u64)60*60*24*PIT_TICK_RATE / PIT_TICK_INTERVAL)
226 // Calculate the timer value at 'count' number of full timer ticks in
229 calc_future_timer_ticks(u32 count)
231 return (GET_BDA(timer_counter) + count + 1) % TICKS_PER_DAY;
234 // Return the timer value that is 'msecs' time in the future.
236 calc_future_timer(u32 msecs)
239 return GET_BDA(timer_counter);
240 u32 kticks = DIV_ROUND_UP((u64)msecs * PIT_TICK_RATE, PIT_TICK_INTERVAL);
241 u32 ticks = DIV_ROUND_UP(kticks, 1000);
242 return calc_future_timer_ticks(ticks);
245 // Check if the given timer value has passed.
249 return (((GET_BDA(timer_counter) + TICKS_PER_DAY - end) % TICKS_PER_DAY)
250 < (TICKS_PER_DAY/2));
253 // get current clock count
255 handle_1a00(struct bregs *regs)
258 u32 ticks = GET_BDA(timer_counter);
259 regs->cx = ticks >> 16;
261 regs->al = GET_BDA(timer_rollover);
262 SET_BDA(timer_rollover, 0); // reset flag
266 // Set Current Clock Count
268 handle_1a01(struct bregs *regs)
270 u32 ticks = (regs->cx << 16) | regs->dx;
271 SET_BDA(timer_counter, ticks);
272 SET_BDA(timer_rollover, 0); // reset flag
273 // XXX - should use set_code_success()?
280 handle_1a02(struct bregs *regs)
282 if (rtc_updating()) {
287 regs->dh = inb_cmos(CMOS_RTC_SECONDS);
288 regs->cl = inb_cmos(CMOS_RTC_MINUTES);
289 regs->ch = inb_cmos(CMOS_RTC_HOURS);
290 regs->dl = inb_cmos(CMOS_STATUS_B) & RTC_B_DSE;
298 handle_1a03(struct bregs *regs)
300 // Using a debugger, I notice the following masking/setting
301 // of bits in Status Register B, by setting Reg B to
302 // a few values and getting its value after INT 1A was called.
305 // before 1111 1101 0111 1101 0000 0000
306 // after 0110 0010 0110 0010 0000 0010
308 // Bit4 in try#1 flipped in hardware (forced low) due to bit7=1
309 // My assumption: RegB = ((RegB & 01100000b) | 00000010b)
310 if (rtc_updating()) {
312 // fall through as if an update were not in progress
314 outb_cmos(regs->dh, CMOS_RTC_SECONDS);
315 outb_cmos(regs->cl, CMOS_RTC_MINUTES);
316 outb_cmos(regs->ch, CMOS_RTC_HOURS);
317 // Set Daylight Savings time enabled bit to requested value
318 u8 val8 = ((inb_cmos(CMOS_STATUS_B) & (RTC_B_PIE|RTC_B_AIE))
319 | RTC_B_24HR | (regs->dl & RTC_B_DSE));
320 outb_cmos(val8, CMOS_STATUS_B);
322 regs->al = val8; // val last written to Reg B
328 handle_1a04(struct bregs *regs)
331 if (rtc_updating()) {
335 regs->cl = inb_cmos(CMOS_RTC_YEAR);
336 regs->dh = inb_cmos(CMOS_RTC_MONTH);
337 regs->dl = inb_cmos(CMOS_RTC_DAY_MONTH);
338 if (CONFIG_COREBOOT) {
344 regs->ch = inb_cmos(CMOS_CENTURY);
352 handle_1a05(struct bregs *regs)
354 // Using a debugger, I notice the following masking/setting
355 // of bits in Status Register B, by setting Reg B to
356 // a few values and getting its value after INT 1A was called.
358 // try#1 try#2 try#3 try#4
359 // before 1111 1101 0111 1101 0000 0010 0000 0000
360 // after 0110 1101 0111 1101 0000 0010 0000 0000
362 // Bit4 in try#1 flipped in hardware (forced low) due to bit7=1
363 // My assumption: RegB = (RegB & 01111111b)
364 if (rtc_updating()) {
369 outb_cmos(regs->cl, CMOS_RTC_YEAR);
370 outb_cmos(regs->dh, CMOS_RTC_MONTH);
371 outb_cmos(regs->dl, CMOS_RTC_DAY_MONTH);
372 if (!CONFIG_COREBOOT)
373 outb_cmos(regs->ch, CMOS_CENTURY);
374 // clear halt-clock bit
375 u8 val8 = inb_cmos(CMOS_STATUS_B) & ~RTC_B_SET;
376 outb_cmos(val8, CMOS_STATUS_B);
378 regs->al = val8; // AL = val last written to Reg B
382 // Set Alarm Time in CMOS
384 handle_1a06(struct bregs *regs)
386 // Using a debugger, I notice the following masking/setting
387 // of bits in Status Register B, by setting Reg B to
388 // a few values and getting its value after INT 1A was called.
391 // before 1101 1111 0101 1111 0000 0000
392 // after 0110 1111 0111 1111 0010 0000
394 // Bit4 in try#1 flipped in hardware (forced low) due to bit7=1
395 // My assumption: RegB = ((RegB & 01111111b) | 00100000b)
396 u8 val8 = inb_cmos(CMOS_STATUS_B); // Get Status Reg B
398 if (val8 & RTC_B_AIE) {
399 // Alarm interrupt enabled already
403 if (rtc_updating()) {
405 // fall through as if an update were not in progress
407 outb_cmos(regs->dh, CMOS_RTC_SECONDS_ALARM);
408 outb_cmos(regs->cl, CMOS_RTC_MINUTES_ALARM);
409 outb_cmos(regs->ch, CMOS_RTC_HOURS_ALARM);
410 // enable Status Reg B alarm bit, clear halt clock bit
411 outb_cmos((val8 & ~RTC_B_SET) | RTC_B_AIE, CMOS_STATUS_B);
417 handle_1a07(struct bregs *regs)
419 // Using a debugger, I notice the following masking/setting
420 // of bits in Status Register B, by setting Reg B to
421 // a few values and getting its value after INT 1A was called.
423 // try#1 try#2 try#3 try#4
424 // before 1111 1101 0111 1101 0010 0000 0010 0010
425 // after 0100 0101 0101 0101 0000 0000 0000 0010
427 // Bit4 in try#1 flipped in hardware (forced low) due to bit7=1
428 // My assumption: RegB = (RegB & 01010111b)
429 u8 val8 = inb_cmos(CMOS_STATUS_B); // Get Status Reg B
430 // clear clock-halt bit, disable alarm bit
431 outb_cmos(val8 & ~(RTC_B_SET|RTC_B_AIE), CMOS_STATUS_B);
433 regs->al = val8; // val last written to Reg B
439 handle_1aXX(struct bregs *regs)
441 set_unimplemented(regs);
444 // INT 1Ah Time-of-day Service Entry Point
446 handle_1a(struct bregs *regs)
448 debug_enter(regs, DEBUG_HDL_1a);
450 case 0x00: handle_1a00(regs); break;
451 case 0x01: handle_1a01(regs); break;
452 case 0x02: handle_1a02(regs); break;
453 case 0x03: handle_1a03(regs); break;
454 case 0x04: handle_1a04(regs); break;
455 case 0x05: handle_1a05(regs); break;
456 case 0x06: handle_1a06(regs); break;
457 case 0x07: handle_1a07(regs); break;
458 case 0xb1: handle_1ab1(regs); break;
459 default: handle_1aXX(regs); break;
463 // INT 08h System Timer ISR Entry Point
467 debug_isr(DEBUG_ISR_08);
471 u32 counter = GET_BDA(timer_counter);
473 // compare to one days worth of timer ticks at 18.2 hz
474 if (counter >= TICKS_PER_DAY) {
475 // there has been a midnight rollover at this point
477 SET_BDA(timer_rollover, GET_BDA(timer_rollover) + 1);
480 SET_BDA(timer_counter, counter);
484 // chain to user timer tick INT #0x1c
486 call16_simpint(0x1c, &eax, &flags);
492 /****************************************************************
494 ****************************************************************/
499 u16 ebda_seg = get_ebda_seg();
500 int count = GET_EBDA2(ebda_seg, RTCusers);
501 SET_EBDA2(ebda_seg, RTCusers, count+1);
504 // Turn on the Periodic Interrupt timer
505 u8 bRegister = inb_cmos(CMOS_STATUS_B);
506 outb_cmos(bRegister | RTC_B_PIE, CMOS_STATUS_B);
512 u16 ebda_seg = get_ebda_seg();
513 int count = GET_EBDA2(ebda_seg, RTCusers);
514 SET_EBDA2(ebda_seg, RTCusers, count-1);
517 // Clear the Periodic Interrupt.
518 u8 bRegister = inb_cmos(CMOS_STATUS_B);
519 outb_cmos(bRegister & ~RTC_B_PIE, CMOS_STATUS_B);
523 set_usertimer(u32 usecs, u16 seg, u16 offset)
525 if (GET_BDA(rtc_wait_flag) & RWS_WAIT_PENDING)
528 // Interval not already set.
529 SET_BDA(rtc_wait_flag, RWS_WAIT_PENDING); // Set status byte.
530 SET_BDA(user_wait_complete_flag, SEGOFF(seg, offset));
531 SET_BDA(user_wait_timeout, usecs);
537 clear_usertimer(void)
539 if (!(GET_BDA(rtc_wait_flag) & RWS_WAIT_PENDING))
541 // Turn off status byte.
542 SET_BDA(rtc_wait_flag, 0);
546 #define RET_ECLOCKINUSE 0x83
548 // Wait for CX:DX microseconds
550 handle_1586(struct bregs *regs)
552 // Use the rtc to wait for the specified time.
554 u32 count = (regs->cx << 16) | regs->dx;
555 int ret = set_usertimer(count, GET_SEG(SS), (u32)&statusflag);
557 set_code_invalid(regs, RET_ECLOCKINUSE);
565 // Set Interval requested.
567 handle_158300(struct bregs *regs)
569 int ret = set_usertimer((regs->cx << 16) | regs->dx, regs->es, regs->bx);
571 // Interval already set.
572 set_code_invalid(regs, RET_EUNSUPPORTED);
577 // Clear interval requested
579 handle_158301(struct bregs *regs)
586 handle_1583XX(struct bregs *regs)
588 set_code_unimplemented(regs, RET_EUNSUPPORTED);
593 handle_1583(struct bregs *regs)
596 case 0x00: handle_158300(regs); break;
597 case 0x01: handle_158301(regs); break;
598 default: handle_1583XX(regs); break;
602 #define USEC_PER_RTC DIV_ROUND_CLOSEST(1000000, 1024)
604 // int70h: IRQ8 - CMOS RTC
608 debug_isr(DEBUG_ISR_70);
610 // Check which modes are enabled and have occurred.
611 u8 registerB = inb_cmos(CMOS_STATUS_B);
612 u8 registerC = inb_cmos(CMOS_STATUS_C);
614 if (!(registerB & (RTC_B_PIE|RTC_B_AIE)))
616 if (registerC & RTC_B_AIE) {
617 // Handle Alarm Interrupt.
619 call16_simpint(0x4a, &eax, &flags);
621 if (!(registerC & RTC_B_PIE))
624 // Handle Periodic Interrupt.
628 if (!GET_BDA(rtc_wait_flag))
631 // Wait Interval (Int 15, AH=83) active.
632 u32 time = GET_BDA(user_wait_timeout); // Time left in microseconds.
633 if (time < USEC_PER_RTC) {
634 // Done waiting - write to specified flag byte.
635 struct segoff_s segoff = GET_BDA(user_wait_complete_flag);
636 u16 ptr_seg = segoff.seg;
637 u8 *ptr_far = (u8*)(segoff.offset+0);
638 u8 oldval = GET_FARVAR(ptr_seg, *ptr_far);
639 SET_FARVAR(ptr_seg, *ptr_far, oldval | 0x80);
644 time -= USEC_PER_RTC;
645 SET_BDA(user_wait_timeout, time);