mirror of
https://github.com/Mathewnd/Astral.git
synced 2026-11-01 06:58:22 +00:00
Matheus
117 lines
2.8 KiB
C
117 lines
2.8 KiB
C
#include <arch/hpet.h>
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#include <arch/acpi.h>
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#include <arch/pci.h>
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#include <arch/panic.h>
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#include <kernel/vmm.h>
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#include <arch/mmu.h>
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#include <stdio.h>
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#define REGISTER_CAPABILITIES 0
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#define REGISTER_CONFIGURATION 0x10
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#define REGISTER_INTERRUPT 0x20
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#define REGISTER_COUNTER 0xF0
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#define REGISTER_N_CONFIG 0x100
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#define REGISTER_N_COMPARATOR 0x108
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#define REGISTER_N_FSB 0x110
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static uint16_t mintick;
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static void* volatile hpetaddr;
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static uint32_t period;
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static uint64_t nsperiod;
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static uint8_t compcount;
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static uint64_t ticksper100ns;
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static inline void writetocompn(size_t n, size_t offset, uint64_t data){
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*(uint64_t* volatile)(hpetaddr + 0x20*n + offset) = data;
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}
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static inline uint64_t readfromcompn(size_t n, size_t offset){
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return *(uint64_t* volatile)(hpetaddr + 0x100 + 0x20*n + offset);
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}
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static inline uint64_t readfromreg(size_t offset){
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return *(uint64_t* volatile)(hpetaddr + offset);
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}
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static inline void writetoreg(size_t offset, uint64_t data){
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*(uint64_t* volatile)(hpetaddr + offset) = data;
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}
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static void wait_ticks(size_t ticks){
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size_t end = readfromreg(REGISTER_COUNTER) + ticks;
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while(readfromreg(REGISTER_COUNTER) < end) asm("pause");
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}
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time_t hpet_get_ticksperus(){
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return ticksper100ns*10;
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}
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time_t hpet_get_counter(){
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return readfromreg(REGISTER_COUNTER);
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}
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void hpet_wait_us(size_t us){
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size_t usticks = ticksper100ns*10;
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wait_ticks(usticks*us);
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}
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void hpet_wait_ms(size_t ms){
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size_t msticks = ticksper100ns*10000;
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wait_ticks(ms*msticks);
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}
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void hpet_wait_s(size_t s){
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size_t sticks = ticksper100ns*10000000;
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wait_ticks(s*sticks);
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}
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void hpet_init(){
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hpet_t* hpet = acpi_gettable("HPET", 0);
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if(!hpet)
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_panic("No HPET found!\n", 0);
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printf("HPET table at %p\n", hpet);
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mintick = hpet->mintick;
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if(hpet->spacetype == 1) _panic("I/O space hpet not supported", 0);
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printf("HPET configuration space is at %p\n", hpet->address);
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// seabios doesn't report this in the memory map.....
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hpetaddr = vmm_alloc(1, 0);
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vmm_map((void*)hpet->address, hpetaddr, 1, ARCH_MMU_MAP_READ | ARCH_MMU_MAP_WRITE);
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uint64_t capabilities = readfromreg(REGISTER_CAPABILITIES);
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compcount = (capabilities >> 8) & 0b11111;
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period = (capabilities >> 32) & 0xFFFFFFFF;
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nsperiod = period / 1000000;
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ticksper100ns = 100000000 / period;
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printf("%lu comparators at %lu femtosecond ticks (%lu ns, %lu ticks per 100 ns)\n", compcount, period, nsperiod, ticksper100ns);
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// configure so we don't use legacy replacement and clear the counter
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writetoreg(REGISTER_CONFIGURATION, 0); // stop it
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writetoreg(REGISTER_COUNTER, 0);
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writetoreg(REGISTER_CONFIGURATION, 1); // turn it back on
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// TODO add interrupt support. for now only direct reads to the
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// counter will be supported.
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// (this should be enough for calibrating the CPU specific timers)
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}
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