ACPI: SPCR: Use access width to determine mmio usage

The current SPCR code does not check the access width of the MMIO, and
uses a default of 8bit register accesses.  This prevents devices that
only do 16 or 32bit register accesses from working.  By simply checking
this field and setting the MMIO string appropriately, this issue can be
corrected.  To prevent any legacy issues, the code will default to 8bit
accesses if the value is anything but 16 or 32.

Signed-off-by: Jon Mason <jon.mason@broadcom.com>
Signed-off-by: Loc Ho <lho@apm.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/acpi/spcr.c b/drivers/acpi/spcr.c
index 3afa8c1fa12702c251d5d3654e2026ba0ebfcd62..29050630f3da2941946f0770d4a090066688679b 100644 (file)
--- a/drivers/acpi/spcr.c
+++ b/drivers/acpi/spcr.c
@@ -74,8 +74,22 @@ int __init parse_spcr(bool earlycon)
                goto done;
        }
 
-       iotype = table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY ?
-                       "mmio" : "io";
+       if (table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
+               switch (table->serial_port.access_width) {
+               default:
+                       pr_err("Unexpected SPCR Access Width.  Defaulting to byte size\n");
+               case ACPI_ACCESS_SIZE_BYTE:
+                       iotype = "mmio";
+                       break;
+               case ACPI_ACCESS_SIZE_WORD:
+                       iotype = "mmio16";
+                       break;
+               case ACPI_ACCESS_SIZE_DWORD:
+                       iotype = "mmio32";
+                       break;
+               }
+       } else
+               iotype = "io";
 
        switch (table->interface_type) {
        case ACPI_DBG2_ARM_SBSA_32BIT:

diff --git a/include/acpi/acrestyp.h b/include/acpi/acrestyp.h
index f0f7403d2000da2a16fbf34b6d69ae4c1fe78f0a..781cb555c960ea38226ba8ea0fb0365263c4d28f 100644 (file)
--- a/include/acpi/acrestyp.h
+++ b/include/acpi/acrestyp.h
@@ -372,6 +372,13 @@ struct acpi_resource_generic_register {
        u64 address;
 };
 
+/* Generic Address Space Access Sizes */
+#define ACPI_ACCESS_SIZE_UNDEFINED             0
+#define ACPI_ACCESS_SIZE_BYTE                  1
+#define ACPI_ACCESS_SIZE_WORD                  2
+#define ACPI_ACCESS_SIZE_DWORD                 3
+#define ACPI_ACCESS_SIZE_QWORD                 4
+
 struct acpi_resource_gpio {
        u8 revision_id;
        u8 connection_type;