diff options
Diffstat (limited to 'drivers/acpi/tables/tbxfroot.c')
| -rw-r--r-- | drivers/acpi/tables/tbxfroot.c | 11 |
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 = |