2 * This file is part of the Palacios Virtual Machine Monitor developed
3 * by the V3VEE Project with funding from the United States National
4 * Science Foundation and the Department of Energy.
6 * The V3VEE Project is a joint project between Northwestern University
7 * and the University of New Mexico. You can find out more at
10 * Copyright (c) 2008, Jack Lange <jarusl@cs.northwestern.edu>
11 * Copyright (c) 2008, The V3VEE Project <http://www.v3vee.org>
12 * All rights reserved.
14 * Author: Jack Lange <jarusl@cs.northwestern.edu>
16 * This is free software. You are permitted to use,
17 * redistribute, and modify it as specified in the file "V3VEE_LICENSE".
21 #include <palacios/vmm.h>
22 #include <palacios/vmm_dev_mgr.h>
23 #include <palacios/vmm_time.h>
24 #include <palacios/vmm_util.h>
25 #include <palacios/vmm_intr.h>
26 #include <palacios/vmm_config.h>
27 #include <palacios/vmm_io.h>
30 #ifndef CONFIG_DEBUG_PIT
32 #define PrintDebug(fmt, args...)
38 #define OSC_HZ 1193182
41 /* The 8254 has three counters and one control port */
42 #define CHANNEL0_PORT 0x40
43 #define CHANNEL1_PORT 0x41
44 #define CHANNEL2_PORT 0x42
45 #define COMMAND_PORT 0x43
46 #define SPEAKER_PORT 0x61
49 #define PIT_INTR_NUM 0
50 #define PIT_SPEAKER_GATE 0x01
52 /* The order of these typedefs is important because the numerical values correspond to the
53 * values coming from the io ports
55 typedef enum {NOT_RUNNING, PENDING, RUNNING} channel_run_state_t;
56 typedef enum {NOT_WAITING, WAITING_LOBYTE, WAITING_HIBYTE} channel_access_state_t;
57 typedef enum {LATCH_COUNT, LOBYTE_ONLY, HIBYTE_ONLY, LOBYTE_HIBYTE} channel_access_mode_t;
58 typedef enum {IRQ_ON_TERM_CNT, ONE_SHOT, RATE_GEN, SQR_WAVE, SW_STROBE, HW_STROBE} channel_op_mode_t;
62 channel_access_mode_t access_mode;
63 channel_access_state_t access_state;
64 channel_run_state_t run_state;
66 channel_op_mode_t op_mode;
69 // Time til interrupt trigger
72 ushort_t reload_value;
74 ushort_t latched_value;
76 enum {NOTLATCHED, LATCHED} latch_state;
78 enum {LSB, MSB} read_state;
80 uint_t output_pin : 1;
81 uint_t gate_input_pin : 1;
90 struct v3_timer * timer;
102 uint_t access_mode : 2;
106 struct pit_rdb_cmd_word {
107 uint_t rsvd : 1; // SBZ
111 uint_t latch_status : 1;
112 uint_t latch_count : 1;
113 uint_t readback_cmd : 2; // Must Be 0x3
116 struct pit_rdb_status_word {
119 uint_t access_mode : 2;
120 uint_t null_count : 1;
121 uint_t pin_state : 1;
127 * This should call out to handle_SQR_WAVE_tics, etc...
129 // Returns true if the the output signal changed state
130 static int handle_crystal_tics(struct pit * pit, struct channel * ch, uint_t oscillations) {
131 uint_t channel_cycles = 0;
132 uint_t output_changed = 0;
134 // PrintDebug("8254 PIT: %d crystal tics\n", oscillations);
135 if (ch->run_state == PENDING) {
137 ch->counter = ch->reload_value;
139 if (ch->op_mode == SQR_WAVE) {
140 ch->counter -= ch->counter % 2;
143 ch->run_state = RUNNING;
144 } else if (ch->run_state != RUNNING) {
145 return output_changed;
149 PrintDebug("8254 PIT: Channel Run State = %d, counter=", ch->run_state);
150 PrintTraceLL(ch->counter);
153 if (ch->op_mode == SQR_WAVE) {
157 if (ch->counter > oscillations) {
158 ch->counter -= oscillations;
159 return output_changed;
161 ushort_t reload_val = ch->reload_value;
163 if (ch->op_mode == SW_STROBE) {
167 oscillations -= ch->counter;
171 if (ch->op_mode == SQR_WAVE) {
172 reload_val -= reload_val % 2;
175 // TODO: Check this....
176 // Is this correct???
177 if (reload_val == 0) {
181 channel_cycles += oscillations / reload_val;
182 oscillations = oscillations % reload_val;
184 ch->counter = reload_val - oscillations;
187 // PrintDebug("8254 PIT: Channel Cycles: %d\n", channel_cycles);
191 switch (ch->op_mode) {
192 case IRQ_ON_TERM_CNT:
193 if ((channel_cycles > 0) && (ch->output_pin == 0)) {
199 if ((channel_cycles > 0) && (ch->output_pin == 0)) {
205 // See the data sheet: we ignore the output pin cycle...
206 if (channel_cycles > 0) {
211 ch->output_pin = (ch->output_pin + 1) % 2;
213 if (ch->output_pin == 1) {
220 if (channel_cycles > 0) {
221 if (ch->output_pin == 1) {
228 PrintError("Hardware strobe not implemented\n");
235 return output_changed;
239 #include <palacios/vm_guest.h>
241 static void pit_update_timer(struct guest_info * info, ullong_t cpu_cycles, ullong_t cpu_freq, void * private_data) {
242 struct pit * state = (struct pit *)private_data;
243 // ullong_t tmp_ctr = state->pit_counter;
245 uint_t oscillations = 0;
249 PrintDebug("updating cpu_cycles=");
250 PrintTraceLL(cpu_cycles);
253 PrintDebug("pit_counter=");
254 PrintTraceLL(state->pit_counter);
257 PrintDebug("pit_reload=");
258 PrintTraceLL(state->pit_reload);
262 if (state->pit_counter > cpu_cycles) {
264 state->pit_counter -= cpu_cycles;
266 ushort_t reload_val = state->pit_reload;
267 // Take off the first part
268 cpu_cycles -= state->pit_counter;
269 state->pit_counter = 0;
272 if (cpu_cycles > state->pit_reload) {
273 // how many full oscillations
275 //PrintError("cpu_cycles = %p, reload = %p...\n",
276 // (void *)(addr_t)cpu_cycles,
277 // (void *)(addr_t)state->pit_reload);
279 // How do we check for a one shot....
280 if (state->pit_reload == 0) {
284 tmp_cycles = cpu_cycles;
288 cpu_cycles = tmp_cycles % state->pit_reload;
289 tmp_cycles = tmp_cycles / state->pit_reload;
291 cpu_cycles = do_divll(tmp_cycles, state->pit_reload);
294 oscillations += tmp_cycles;
297 // update counter with remainder (mod reload)
298 state->pit_counter = state->pit_reload - cpu_cycles;
300 //PrintDebug("8254 PIT: Handling %d crystal tics\n", oscillations);
301 if (handle_crystal_tics(state, &(state->ch_0), oscillations) == 1) {
303 PrintDebug("8254 PIT: Injecting Timer interrupt to guest\n");
304 v3_raise_irq(info->vm_info, 0);
307 //handle_crystal_tics(state, &(state->ch_1), oscillations);
308 handle_crystal_tics(state, &(state->ch_2), oscillations);
317 /* This should call out to handle_SQR_WAVE_write, etc...
319 static int handle_channel_write(struct channel * ch, char val) {
321 switch (ch->access_state) {
324 ushort_t tmp_val = ((ushort_t)val) << 8;
325 ch->reload_value &= 0x00ff;
326 ch->reload_value |= tmp_val;
329 if ((ch->op_mode != RATE_GEN) || (ch->run_state != RUNNING)){
330 ch->run_state = PENDING;
333 if (ch->access_mode == LOBYTE_HIBYTE) {
334 ch->access_state = WAITING_LOBYTE;
337 PrintDebug("8254 PIT: updated channel counter: %d\n", ch->reload_value);
338 PrintDebug("8254 PIT: Channel Run State=%d\n", ch->run_state);
342 ch->reload_value &= 0xff00;
343 ch->reload_value |= val;
345 if (ch->access_mode == LOBYTE_HIBYTE) {
346 ch->access_state = WAITING_HIBYTE;
347 } else if ((ch->op_mode != RATE_GEN) || (ch->run_state != RUNNING)) {
348 ch->run_state = PENDING;
351 PrintDebug("8254 PIT: updated channel counter: %d\n", ch->reload_value);
352 PrintDebug("8254 PIT: Channel Run State=%d\n", ch->run_state);
355 PrintError("Invalid Access state\n");
360 switch (ch->op_mode) {
361 case IRQ_ON_TERM_CNT:
377 PrintError("Invalid OP_MODE: %d\n", ch->op_mode);
387 static int handle_channel_read(struct channel * ch, char * val) {
391 if (ch->latch_state == NOTLATCHED) {
392 myval = &(ch->counter);
394 myval = &(ch->latched_value);
397 if (ch->read_state == LSB) {
398 *val = ((char*)myval)[0]; // little endian
399 ch->read_state = MSB;
401 *val = ((char*)myval)[1];
402 ch->read_state = LSB;
403 if (ch->latch_state == LATCHED) {
404 ch->latch_state = NOTLATCHED;
412 static int handle_speaker_read(uint8_t *speaker, struct channel * ch, char * val) {
415 if ((*speaker & PIT_SPEAKER_GATE)) {
416 *val |= (ch->output_pin << 5);
422 static int handle_speaker_write(uint8_t *speaker, struct channel * ch, char val) {
423 *speaker = (val & ~0x20);
427 static int handle_channel_cmd(struct channel * ch, struct pit_cmd_word cmd) {
428 ch->op_mode = cmd.op_mode;
429 ch->access_mode = cmd.access_mode;
434 switch (cmd.access_mode) {
436 if (ch->latch_state == NOTLATCHED) {
437 ch->latched_value = ch->counter;
438 ch->latch_state = LATCHED;
442 ch->access_state = WAITING_HIBYTE;
446 ch->access_state = WAITING_LOBYTE;
451 switch (cmd.op_mode) {
452 case IRQ_ON_TERM_CNT:
468 PrintError("Invalid OP_MODE: %d\n", cmd.op_mode);
479 static int pit_read_channel(struct guest_info * core, ushort_t port, void * dst, uint_t length, void * priv_data) {
480 struct pit * state = (struct pit *)priv_data;
481 char * val = (char *)dst;
484 PrintError("8254 PIT: Invalid Read Write length \n");
488 PrintDebug("8254 PIT: Read of PIT Channel %d\n", port - CHANNEL0_PORT);
492 if (handle_channel_read(&(state->ch_0), val) == -1) {
493 PrintError("CHANNEL0 read error\n");
498 if (handle_channel_read(&(state->ch_1), val) == -1) {
499 PrintError("CHANNEL1 read error\n");
504 if (handle_channel_read(&(state->ch_2), val) == -1) {
505 PrintError("CHANNEL2 read error\n");
510 if (handle_speaker_read(&state->speaker, &(state->ch_2), val) == -1) {
511 PrintError("SPEAKER read error\n");
516 PrintError("8254 PIT: Read from invalid port (%d)\n", port);
525 static int pit_write_channel(struct guest_info * core, ushort_t port, void * src, uint_t length, void * priv_data) {
526 struct pit * state = (struct pit *)priv_data;
527 char val = *(char *)src;
530 PrintError("8254 PIT: Invalid Write Length\n");
534 PrintDebug("8254 PIT: Write to PIT Channel %d (%x)\n", port - CHANNEL0_PORT, *(char*)src);
539 if (handle_channel_write(&(state->ch_0), val) == -1) {
540 PrintError("CHANNEL0 write error\n");
545 if (handle_channel_write(&(state->ch_1), val) == -1) {
546 PrintError("CHANNEL1 write error\n");
551 if (handle_channel_write(&(state->ch_2), val) == -1) {
552 PrintError("CHANNEL2 write error\n");
557 if (handle_speaker_write(&state->speaker, &(state->ch_2), val) == -1) {
558 PrintError("SPEAKER write error\n");
563 PrintError("8254 PIT: Write to invalid port (%d)\n", port);
573 static int pit_write_command(struct guest_info * core, ushort_t port, void * src, uint_t length, void * priv_data) {
574 struct pit * state = (struct pit *)priv_data;
575 struct pit_cmd_word * cmd = (struct pit_cmd_word *)src;
577 PrintDebug("8254 PIT: Write to PIT Command port\n");
578 PrintDebug("8254 PIT: Writing to channel %d (access_mode = %d, op_mode = %d)\n", cmd->channel, cmd->access_mode, cmd->op_mode);
580 PrintError("8254 PIT: Write of Invalid length to command port\n");
584 switch (cmd->channel) {
586 if (handle_channel_cmd(&(state->ch_0), *cmd) == -1) {
587 PrintError("CHANNEL0 command error\n");
592 if (handle_channel_cmd(&(state->ch_1), *cmd) == -1) {
593 PrintError("CHANNEL1 command error\n");
598 if (handle_channel_cmd(&(state->ch_2), *cmd) == -1) {
599 PrintError("CHANNEL2 command error\n");
605 PrintError("Read back command not implemented\n");
619 static struct v3_timer_ops timer_ops = {
620 .update_timer = pit_update_timer,
624 static void init_channel(struct channel * ch) {
625 ch->run_state = NOT_RUNNING;
626 ch->access_state = NOT_WAITING;
631 ch->reload_value = 0;
633 ch->gate_input_pin = 0;
635 ch->latched_value = 0;
636 ch->latch_state = NOTLATCHED;
637 ch->read_state = LSB;
645 static int pit_free(struct vm_device * dev) {
646 struct pit * state = (struct pit *)dev->private_data;
647 struct guest_info * info = &(dev->vm->cores[0]);
651 v3_remove_timer(info, state->timer);
659 static struct v3_device_ops dev_ops = {
665 #include <palacios/vm_guest.h>
667 static int pit_init(struct v3_vm_info * vm, v3_cfg_tree_t * cfg) {
668 struct pit * pit_state = NULL;
669 struct vm_device * dev = NULL;
670 char * dev_id = v3_cfg_val(cfg, "ID");
673 // PIT is only usable in non-multicore environments
674 // just hardcode the core context
675 struct guest_info * info = &(vm->cores[0]);
677 uint_t cpu_khz = V3_CPU_KHZ();
678 ullong_t reload_val = (ullong_t)cpu_khz * 1000;
680 pit_state = (struct pit *)V3_Malloc(sizeof(struct pit));
681 V3_ASSERT(pit_state != NULL);
682 pit_state->speaker = 0;
684 dev = v3_allocate_device(dev_id, &dev_ops, pit_state);
686 if (v3_attach_device(vm, dev) == -1) {
687 PrintError("Could not attach device %s\n", dev_id);
692 ret |= v3_dev_hook_io(dev, CHANNEL0_PORT, &pit_read_channel, &pit_write_channel);
693 ret |= v3_dev_hook_io(dev, CHANNEL1_PORT, &pit_read_channel, &pit_write_channel);
694 ret |= v3_dev_hook_io(dev, CHANNEL2_PORT, &pit_read_channel, &pit_write_channel);
695 ret |= v3_dev_hook_io(dev, COMMAND_PORT, NULL, &pit_write_command);
696 ret |= v3_dev_hook_io(dev, SPEAKER_PORT, &pit_read_channel, &pit_write_channel);
699 PrintError("8254 PIT: Failed to hook IO ports\n");
700 v3_detach_device(dev);
704 #ifdef CONFIG_DEBUG_PIT
705 PrintDebug("8254 PIT: OSC_HZ=%d, reload_val=", OSC_HZ);
706 //PrintTrace(reload_val);
712 pit_state->timer = v3_add_timer(info, &timer_ops, pit_state);
714 if (pit_state->timer == NULL) {
715 v3_detach_device(dev);
719 // Get cpu frequency and calculate the global pit oscilattor counter/cycle
721 do_divll(reload_val, OSC_HZ);
722 pit_state->pit_counter = reload_val;
723 pit_state->pit_reload = reload_val;
726 init_channel(&(pit_state->ch_0));
727 init_channel(&(pit_state->ch_1));
728 init_channel(&(pit_state->ch_2));
730 #ifdef CONFIG_DEBUG_PIT
731 PrintDebug("8254 PIT: CPU MHZ=%d -- pit count=", cpu_khz / 1000);
732 //PrintTraceLL(pit_state->pit_counter);
740 device_register("8254_PIT", pit_init);