org

kernel/acpi/rsdp.c

@@ -0,0 +1,116 @@
+#include <stdint.h>
+
+#include "../io/io.h"
+#include "../memory/memory.h"
+#include "rsdp.h"
+
+struct rsdp_t {
+  char     signature[8];
+  uint8_t  checksum;
+  char     oem_id[6];
+  uint8_t  revision;
+  uint32_t rsdt_address;
+} __attribute__((packed));
+
+struct xsdp_t {
+  char     signature[8];
+  uint8_t  checksum;
+  char     oem_id[6];
+  uint8_t  revision;
+  uint32_t unused;
+  uint32_t length;
+  uint32_t xsdt_addr_hi;
+  uint32_t xsdt_addr_lo;
+  uint8_t  checksum_ext;
+  uint8_t  unused_[3];
+} __attribute__((packed));
+
+struct acpi_header_t {
+  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_division;
+} __attribute__((packed));
+
+struct rsdt_t {
+  struct acpi_header_t header;
+  uint32_t             pointer[64];
+};
+
+uint8_t validate(struct rsdp_t *ptr) {
+  char sig[] = "RSD PTR ";
+  if (!memseq(ptr->signature, sig, 8))
+    return 0;
+
+  uint8_t *rsdp_bytes = (uint8_t *)ptr;
+  uint8_t  sum = 0;
+  for (uint8_t i = 0; i < 20; i++) {
+    sum += rsdp_bytes[i];
+  }
+
+  if (sum == 0 && ptr->revision == 2) {
+    printf_nolock("acpi: ACPI v2+ not yet supported :(\n");
+    for (;;) {
+    }
+    // TODO: test with ACPI 2 System
+    struct xsdp_t *r2_ptr = (struct xsdp_t *)ptr;
+
+    uint8_t *xsdp_bytes = ((uint8_t *)r2_ptr) + 8;
+    for (uint8_t i = 0; i < 16; i++) {
+      sum += xsdp_bytes[i];
+    }
+  }
+
+  return sum == 0;
+}
+
+char *find_table(struct rsdt_t *table, char *sig) {
+  uint32_t entries = (table->header.length - sizeof table->header) / 4;
+  for (uint32_t i = 0; i < entries; i++) {
+    struct acpi_header_t *entry = (struct acpi_header_t *)table->pointer[i];
+    if (memseq(entry->signature, sig, 4)) {
+      printf_nolock("Found %s /  %s\n", entry->oem_id, entry->signature);
+      printf_nolock("Signature: %s\n", entry->signature);
+      printf_nolock("Length   : %d\n", entry->length);
+      printf_nolock("Oem ID   : %s\n", entry->oem_id);
+      printf_nolock("Checksum : %d\n", entry->checksum);
+      return (void *)entry;
+    }
+  }
+
+  printf_nolock("Not Found");
+  return 0;
+}
+
+void find_rsdp() {
+  struct rsdp_t *ptr;
+
+  volatile uint8_t found = 0;
+  for (uint32_t addr = 0x00000000; addr <= 0x000FFFFF; addr++) {
+    ptr = (struct rsdp_t *)addr;
+
+    if (validate(ptr)) {
+      found = 1;
+      break;
+    }
+  }
+
+  if (!found) {
+    uint8_t *ebda = (uint8_t *)(*((uint16_t *)0x40e) << 4);
+    for (uint32_t i = 0; i <= 1024; i += 16) {
+      ptr = (struct rsdp_t *)ebda;
+      if (validate(ptr)) {
+        found = 1;
+        break;
+      }
+    }
+  }
+
+  printf_nolock("acpi: RSDP Found [OEM: %s, SIG:  %s]\n", ptr->oem_id,
+                ptr->signature);
+}

kernel/acpi/rsdp.h

@@ -0,0 +1,3 @@
+#pragma once
+
+void find_rsdp();