[PATCH 2/6] ACPI: Teach ACPI table parsing about the CEDT header format

[Dan Williams <dan.j.williams@xxxxxxxxx>]

The CEDT adds yet one more unique subtable header type where the length
is a 16-bit value. Extend the subtable helpers to detect this scenario.

Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx>
Cc: Len Brown <lenb@xxxxxxxxxx>
Tested-by: Alison Schofield <alison.schofield@xxxxxxxxx>
Reviewed-by: Alison Schofield <alison.schofield@xxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
 drivers/acpi/tables.c |    9 +++++++++
 include/linux/acpi.h  |    1 +
 2 files changed, 10 insertions(+)

diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c
index 29d44fe19ef0..b1514fde11bc 100644
--- a/drivers/acpi/tables.c
+++ b/drivers/acpi/tables.c
@@ -40,6 +40,7 @@ enum acpi_subtable_type {
 	ACPI_SUBTABLE_COMMON,
 	ACPI_SUBTABLE_HMAT,
 	ACPI_SUBTABLE_PRMT,
+	ACPI_SUBTABLE_CEDT,
 };
 
 struct acpi_subtable_entry {
@@ -225,6 +226,8 @@ acpi_get_entry_type(struct acpi_subtable_entry *entry)
 		return entry->hdr->hmat.type;
 	case ACPI_SUBTABLE_PRMT:
 		return 0;
+	case ACPI_SUBTABLE_CEDT:
+		return entry->hdr->cedt.type;
 	}
 	return 0;
 }
@@ -239,6 +242,8 @@ acpi_get_entry_length(struct acpi_subtable_entry *entry)
 		return entry->hdr->hmat.length;
 	case ACPI_SUBTABLE_PRMT:
 		return entry->hdr->prmt.length;
+	case ACPI_SUBTABLE_CEDT:
+		return entry->hdr->cedt.length;
 	}
 	return 0;
 }
@@ -253,6 +258,8 @@ acpi_get_subtable_header_length(struct acpi_subtable_entry *entry)
 		return sizeof(entry->hdr->hmat);
 	case ACPI_SUBTABLE_PRMT:
 		return sizeof(entry->hdr->prmt);
+	case ACPI_SUBTABLE_CEDT:
+		return sizeof(entry->hdr->cedt);
 	}
 	return 0;
 }
@@ -264,6 +271,8 @@ acpi_get_subtable_type(char *id)
 		return ACPI_SUBTABLE_HMAT;
 	if (strncmp(id, ACPI_SIG_PRMT, 4) == 0)
 		return ACPI_SUBTABLE_PRMT;
+	if (strncmp(id, ACPI_SIG_CEDT, 4) == 0)
+		return ACPI_SUBTABLE_CEDT;
 	return ACPI_SUBTABLE_COMMON;
 }
 
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 509b72676e2e..cbee050f4b1d 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -133,6 +133,7 @@ union acpi_subtable_headers {
 	struct acpi_subtable_header common;
 	struct acpi_hmat_structure hmat;
 	struct acpi_prmt_module_header prmt;
+	struct acpi_cedt_header cedt;
 };
 
 typedef int (*acpi_tbl_table_handler)(struct acpi_table_header *table);