acpi + lib

include/acpi.h

@@ -0,0 +1,23 @@
+
+enum acpi_status {
+	ACPI_SUCCESS = 0,
+	ACPI_FAILURE = -1,
+	ACPI_MALFORMED_TABLE = -2,
+	ACPI_OLD_VERSION = -4,
+	ACPI_S5_PARSE_ERROR = -5,
+};
+
+/**
+ * Loads the ACPI tables
+ * https://en.wikipedia.org/wiki/ACPI
+ * @param rsdp - pointer to the Root System Description Pointer
+ * usually passed from the bootlater
+ * @returns ACPI_SUCCESS on success
+ */
+int acpi_init(void *rsdp);
+
+/**
+ * Shutdowns down the system
+ * @returns ACPI_FAILURE on failure
+ */
+int acpi_shutdown(void);

include/lib.h

@@ -0,0 +1,12 @@
+
+/**
+ * The  strcmp()  function  compares  the two strings s1 and s2.  The locale is not taken into account
+ * (for a locale-aware comparison, see strcoll(3)).  The comparison is done using unsigned characters.
+ */
+int strncmp(const char *s1, const char *s2, unsigned long n);
+
+/**
+ * The  memcmp() function compares the first n bytes (each interpreted as unsigned char) of the memory
+ * areas s1 and s2.
+ */
+int memcmp(const void *s1, const void *s2, unsigned long n);

src/arch/amd64/acpi.c

@@ -0,0 +1,223 @@
+#include "arch/amd64/bindings.h"
+#include <acpi.h>
+#include <lib.h>
+
+#include <stdint.h>
+#include <stddef.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;
+}

src/lib.c

@@ -0,0 +1,14 @@
+#include <lib.h>
+
+int strncmp(const char *lhs, const char *rhs, unsigned long n) {
+	const unsigned char *l=(void *)lhs, *r=(void *)rhs;
+	if (!n--) return 0;
+	for (; *l && *r && n && *l == *r ; l++, r++, n--);
+	return *l - *r;
+}
+
+int memcmp(const void *vl, const void *vr, unsigned long n) {
+    const unsigned char *l = vl, *r = vr;
+    for (; n && *l == *r; n--, l++, r++);
+    return n ? *l-*r : 0;
+}