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path: root/drivers/acpi/tables/tbxfroot.c
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Diffstat (limited to 'drivers/acpi/tables/tbxfroot.c')
-rw-r--r--drivers/acpi/tables/tbxfroot.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/acpi/tables/tbxfroot.c b/drivers/acpi/tables/tbxfroot.c
index a62db6af83c9..7f68b759f15a 100644
--- a/drivers/acpi/tables/tbxfroot.c
+++ b/drivers/acpi/tables/tbxfroot.c
@@ -75,6 +75,7 @@ acpi_status acpi_tb_validate_rsdp(struct rsdp_descriptor *rsdp)
* The signature and checksum must both be correct
*/
if (ACPI_STRNCMP((char *)rsdp, RSDP_SIG, sizeof(RSDP_SIG) - 1) != 0) {
+
/* Nope, BAD Signature */
return (AE_BAD_SIGNATURE);
@@ -217,6 +218,7 @@ acpi_get_firmware_table(acpi_string signature,
/* Ensure that we have a RSDP */
if (!acpi_gbl_RSDP) {
+
/* Get the RSDP */
status = acpi_os_get_root_pointer(flags, &address);
@@ -327,10 +329,12 @@ acpi_get_firmware_table(acpi_string signature,
/* Compare table signatures and table instance */
if (!ACPI_STRNCMP(header->signature, signature, ACPI_NAME_SIZE)) {
+
/* An instance of the table was found */
j++;
if (j >= instance) {
+
/* Found the correct instance, get the entire table */
status =
@@ -434,12 +438,14 @@ static u8 *acpi_tb_scan_memory_for_rsdp(u8 * start_address, u32 length)
for (mem_rover = start_address; mem_rover < end_address;
mem_rover += ACPI_RSDP_SCAN_STEP) {
+
/* The RSDP signature and checksum must both be correct */
status =
acpi_tb_validate_rsdp(ACPI_CAST_PTR
(struct rsdp_descriptor, mem_rover));
if (ACPI_SUCCESS(status)) {
+
/* Sig and checksum valid, we have found a real RSDP */
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
@@ -495,6 +501,7 @@ acpi_tb_find_rsdp(struct acpi_table_desc *table_info, u32 flags)
* Scan supports either logical addressing or physical addressing
*/
if ((flags & ACPI_MEMORY_MODE) == ACPI_LOGICAL_ADDRESSING) {
+
/* 1a) Get the location of the Extended BIOS Data Area (EBDA) */
status = acpi_os_map_memory((acpi_physical_address)
@@ -542,6 +549,7 @@ acpi_tb_find_rsdp(struct acpi_table_desc *table_info, u32 flags)
acpi_os_unmap_memory(table_ptr, ACPI_EBDA_WINDOW_SIZE);
if (mem_rover) {
+
/* Return the physical address */
physical_address +=
@@ -576,6 +584,7 @@ acpi_tb_find_rsdp(struct acpi_table_desc *table_info, u32 flags)
acpi_os_unmap_memory(table_ptr, ACPI_HI_RSDP_WINDOW_SIZE);
if (mem_rover) {
+
/* Return the physical address */
physical_address =
@@ -609,6 +618,7 @@ acpi_tb_find_rsdp(struct acpi_table_desc *table_info, u32 flags)
(physical_address),
ACPI_EBDA_WINDOW_SIZE);
if (mem_rover) {
+
/* Return the physical address */
table_info->physical_address =
@@ -624,6 +634,7 @@ acpi_tb_find_rsdp(struct acpi_table_desc *table_info, u32 flags)
(ACPI_HI_RSDP_WINDOW_BASE),
ACPI_HI_RSDP_WINDOW_SIZE);
if (mem_rover) {
+
/* Found it, return the physical address */
table_info->physical_address =