Began system management bios implementation and fixed things

1 files changed, 66 insertions, 0 deletions

diff --git a/src/kernel/smbios/smbios.c b/src/kernel/smbios/smbios.c
new file mode 100644
index 0000000..0275f48
--- /dev/null
+++ b/src/kernel/smbios/smbios.c
@@ -0,0 +1,66 @@
+#include <stdint.h>
+#include <kernel/graphics/vesa.h>
+#include <stddef.h>
+#include <kernel/io/io.h>
+#include <kernel/smbios/smbios.h>
+
+struct smbios_entry {
+    int8_t signature[4];
+    uint8_t checksum;
+    uint8_t length;
+    uint8_t major_version;
+    uint8_t minor_version;
+    uint8_t max_structure_size;
+    int8_t entry_point_revision;
+    int8_t formatted_area[5];
+    int8_t entry_point_signature[5];
+    uint8_t checksum2;
+    uint16_t table_length;
+    uint32_t table_address;
+    uint16_t number_of_structures;
+    uint8_t bcd_revision;
+};
+
+struct smbios_entry *smbios = 0;
+
+size_t smbios_table_len(struct smbios_header *header) {
+    size_t i;
+    const char *strtab = (char *) header + header->length;
+    for (i = 1; strtab[i - 1] != '\0' || strtab[i] != '\0'; i++);
+    return header->length + i + 1;
+}
+
+struct smbios_entry *get_smbios() {
+    if (smbios != 0) return smbios;
+
+    char *mem = (char *) 0xF0000;
+    int length, i;
+    unsigned char checksum;
+    while ((unsigned int) mem < 0x100000) {
+        if (mem[0] == '_' && mem[1] == 'S' && mem[2] == 'M' && mem[3] == '_') {
+            length = mem[5];
+            checksum = 0;
+            for (i = 0; i < length; i++) {
+                checksum += mem[i];
+            }
+            if (checksum == 0) break;
+        }
+        mem += 16;
+    }
+
+    if ((unsigned int) mem == 0x100000) {
+        warn("No SMBIOS found!");
+        return 0;
+    }
+
+    smbios = (struct smbios_entry *) mem;
+    if (smbios->major_version != 2) warn("Non-supported SMBIOS version");
+    smbios_table((struct smbios_header *) mem);
+    return smbios;
+}
+
+void smbios_table(struct smbios_header *header) {
+    serial_write("\n\n");
+    struct smbios_0 *table = (struct smbios_0 *) (header + sizeof(struct smbios_header));
+    serial_write(table->bios_version);
+}