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#include <acpi.h>
#include <lib.h>
#include <stdint.h>
#include <stddef.h>
#include "bindings.h"
/* global state, idk a better way rn */
struct acpi_state state;
struct acpi_header {
char signature[4];
uint32_t length;
uint8_t revision;
uint8_t checksum;
char oem_id[6];
char oem_table_id[8];
uint32_t oem_revision;
uint32_t creator_id;
uint32_t creator_revision;
};
// eXtended system descriptor pointer
struct xsdp {
char signature[8];
uint8_t checksum;
char oemid[6];
uint8_t revision;
uint32_t rsdt_addr;
uint32_t length;
uint64_t xsdt_addr;
uint8_t extendeid_checksum;
uint8_t reserved[3];
} __attribute__((packed));
// eXtended system descriptor table
struct xsdt {
struct acpi_header h;
uint64_t sdt_pointers[];
};
// generic address structure
struct gas {
uint8_t address_space;
uint8_t bit_width;
uint8_t bit_offset;
uint8_t access_size;
uint64_t address;
};
// fixed acpi description table
struct fadt {
struct acpi_header h;
uint32_t firmware_ctrl;
uint32_t dsdt;
// field used in ACPI 1.0; no longer in use, for compatibility only
uint8_t reserved;
uint8_t preferred_power_management_profile;
uint16_t sci_interrupt;
uint32_t smi_command_port;
uint8_t acpi_enable;
uint8_t acpi_disable;
uint8_t s4bios_req;
uint8_t pstate_control;
uint32_t pm1_a_event_block;
uint32_t pm1_b_event_block;
uint32_t pm1_a_control_block;
uint32_t pm1_b_control_block;
uint32_t pm2_control_block;
uint32_t pm_timer_block;
uint32_t gpe0_block;
uint32_t gpe1_block;
uint8_t pm1_event_length;
uint8_t pm1_control_length;
uint8_t pm2_control_length;
uint8_t pm_timer_length;
uint8_t gpe0_length;
uint8_t gpe1_length;
uint8_t gpe1_base;
uint8_t cstate_control;
uint16_t worst_c2_latency;
uint16_t worst_c3_latency;
uint16_t flush_size;
uint16_t flush_stride;
uint8_t duty_offset;
uint8_t duty_width;
uint8_t day_alarm;
uint8_t month_alarm;
uint8_t century;
// reserved in ACPI 1.0; used since ACPI 2.0+
uint16_t boot_architecture_flags;
uint8_t reserved_2;
uint32_t flags;
// 12 byte structure; see below for details
struct gas reset_reg;
uint8_t reset_value;
uint8_t reserved_3[3];
// 64bit pointers - Available on ACPI 2.0+
uint64_t x_firmware_control;
uint64_t x_dsdt;
struct gas x_pm1_a_event_block;
struct gas x_pm1_b_event_block;
struct gas x_pm1_a_control_block;
struct gas x_pm1_b_control_block;
struct gas x_pm2_control_block;
struct gas x_pm_timer_block;
struct gas x_gpe0_block;
struct gas x_gpe1_block;
};
struct acpi_state {
struct fadt fadt;
uint16_t SLP_TYPa;
uint16_t SLP_TYPb;
uint16_t SLP_EN;
uint16_t SCI_EN;
};
static bool checksum(uint8_t *data, size_t len) {
unsigned char sum = 0;
for (size_t i = 0; i < len; i++)
sum += data[i];
return sum == 0;
}
static int read_s5_addr(struct acpi_state *state) {
uintptr_t ptr = state->fadt.dsdt;
char *s5_addr = (void*) (ptr + 36);
int dsdt_len = *((int*) (ptr+1)) - 36;
while (0 < dsdt_len--) {
if ( memcmp(s5_addr, "_S5_", 4) == 0)
break;
s5_addr++;
}
if (dsdt_len > 0) {
// check for valid AML structure
if ( ( *(s5_addr-1) == 0x08 || ( *(s5_addr-2) == 0x08 && *(s5_addr-1) == '\\') ) && *(s5_addr+4) == 0x12 ) {
s5_addr += 5;
s5_addr += ((*s5_addr &0xC0)>>6) +2; // calculate PkgLength size
if (*s5_addr == 0x0A)
s5_addr++; // skip byteprefix
state->SLP_TYPa = *(s5_addr)<<10;
s5_addr++;
if (*s5_addr == 0x0A)
s5_addr++; // skip byteprefix
state->SLP_TYPb = *(s5_addr)<<10;
state->SLP_EN = 1<<13;
state->SCI_EN = 1;
} else {
return ACPI_S5_PARSE_ERROR;
}
} else {
return ACPI_S5_PARSE_ERROR;
}
return ACPI_SUCCESS;
}
static void *acpi_find_table(struct xsdt *xsdt, const char *identifier, int ident_len) {
int entries = (xsdt->h.length - sizeof(xsdt->h)) / 8;
for (int i = 0; i < entries; i++) {
struct acpi_header *h = (struct acpi_header *) (uintptr_t) xsdt->sdt_pointers[i];
if (!strncmp(h->signature, identifier, ident_len))
return (void *)h;
}
// TABLE NOT FOUND
return NULL;
}
int acpi_init(void *rootsdp) {
struct xsdp *xsdp = (struct xsdp *) rootsdp;
if (!checksum((uint8_t *)xsdp, sizeof(struct xsdp)))
return ACPI_MALFORMED_TABLE;
if (xsdp->revision != 2)
return ACPI_OLD_VERSION;
struct xsdt *xsdt = (struct xsdt *) (uintptr_t) xsdp->xsdt_addr;
if (!checksum((uint8_t *) &xsdt->h, xsdt->h.length))
return ACPI_MALFORMED_TABLE;
struct fadt *fadt = acpi_find_table(xsdt, "FACP", 4);
if (!fadt)
return ACPI_MALFORMED_TABLE;
if (!checksum((uint8_t *) &fadt->h, fadt->h.length))
return ACPI_MALFORMED_TABLE;
state.fadt = *fadt;
int ret = read_s5_addr(&state);
if (!ret)
return ret;
outb(state.fadt.smi_command_port,state.fadt.acpi_enable);
return ACPI_SUCCESS;
}
int acpi_shutdown(void) {
outw((unsigned int) state.fadt.pm1_a_control_block, state.SLP_TYPb | state.SLP_EN);
return ACPI_FAILURE;
}
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