* Add validation of the RSDP checksums.

* If we detect ACPI 2.0 or higher, the spec says we should use the XSDT rather
  than the RSDT. Attempt to do so, falling back to the RSDT if the former fails
  to be mapped/validated.
* Refactored acpi_find_table into a templated version to account for the fact
  that the XSDT exports different pointer widths for its links to other tables
  than the RSDT.



git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@42133 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/kernel/arch/x86/arch_acpi.h

@@ -8,11 +8,20 @@
 
 #define ACPI_RSDP_SIGNATURE		"RSD PTR "
 #define ACPI_RSDT_SIGNATURE		"RSDT"
+#define ACPI_XSDT_SIGNATURE		"XSDT"
 #define ACPI_MADT_SIGNATURE		"APIC"
 
 #define ACPI_LOCAL_APIC_ENABLED	0x01
 
-typedef struct acpi_rsdp {
+typedef struct acpi_rsdp_legacy {
+	char	signature[8];			/* "RSD PTR " including blank */
+	uint8	checksum;				/* checksum of bytes 0-19 (per ACPI 1.0) */
+	char	oem_id[6];				/* not null terminated */
+	uint8	revision;				/* 0 = ACPI 1.0, 2 = ACPI 3.0 */
+	uint32	rsdt_address;			/* physical memory address of RSDT */
+} _PACKED acpi_rsdp_legacy;
+
+typedef struct acpi_rsdp_extended {
 	char	signature[8];			/* "RSD PTR " including blank */
 	uint8	checksum;				/* checksum of bytes 0-19 (per ACPI 1.0) */
 	char	oem_id[6];				/* not null terminated */
@@ -22,7 +31,9 @@ typedef struct acpi_rsdp {
 	uint64	xsdt_address;			/* 64bit physical memory address of XSDT */
 	uint8	extended_checksum;		/* including entire table */
 	uint8	reserved[3];
-} _PACKED acpi_rsdp;
+} _PACKED acpi_rsdp_extended;
+
+typedef acpi_rsdp_extended acpi_rsdp;
 
 typedef struct acpi_descriptor_header {
 	char	signature[4];			/* table identifier as ASCII string */