Changeset babcb148 in mainline for arch/ia32/src/acpi/acpi.c

Timestamp:

2005-04-27T21:19:42Z (20 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

10a2e22

Parents:

434f700

Message:

ACPI detection code.
MP detection code rewrite.
Minor changes.

File:

• arch/ia32/src/acpi/acpi.c (modified) (1 diff)

arch/ia32/src/acpi/acpi.c

@@ -28 +28 @@
 
 #include <arch/acpi/acpi.h>
+#include <arch/bios/bios.h>
+
+#define RSDP_SIGNATURE          "RSD PTR "
+#define RSDP_REVISION_OFFS      15
 
 struct acpi_rsdp *acpi_rsdp = NULL;
 
+int rsdp_check(__u8 *rsdp) {
+        struct acpi_rsdp *r = (struct acpi_rsdp *) rsdp;
+        __u8 sum = 0;
+        int i;
+        
+        for (i=0; i<20; i++)
+                sum += rsdp[i];
+                
+        if (sum)        
+                return 0; /* bad checksum */
+
+        if (r->revision == 0)
+                return 1; /* ACPI 1.0 */
+                
+        for (; i<r->length; i++)
+                sum += rsdp[i];
+                
+        return !sum;
+        
+}
+
 void acpi_init(void)
 {
+        __u8 *addr[2] = { NULL, (__u8 *) 0xe0000 };
+        int i, j, length[2] = { 1024, 128*1024 };
+        __u64 *sig = (__u64 *) RSDP_SIGNATURE;
+
+        /*
+         * Find Root System Description Pointer
+         * 1. search first 1K of EBDA
+         * 2. search 128K starting at 0xe0000
+         */
+
+        addr[0] = (__u8 *) ebda;
+        for (i = (ebda ? 0 : 1); i < 2; i++) {
+                for (j = 0; j < length[i]; j += 16) {
+                        if (*((__u64 *) &addr[i][j]) == *sig && rsdp_check(&addr[i][j])) {
+                                acpi_rsdp = (struct acpi_rsdp *) &addr[i][j];
+                                goto rsdp_found;
+                        }
+                }
+        }
+
+        return;
+
+rsdp_found:
+        printf("%L: ACPI Root System Description Pointer\n", acpi_rsdp);                
 }