ACPICA: New: acpi_reset interface - write to reset register

Uses the FADT-defined reset register and reset value. Checks the
FADT flags for the reset register supported bit. Supports reset
register in memory or I/O space, but not in PCI config space
since the host has the information to do it.

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

2 files changed, 39 insertions, 0 deletions

diff --git a/drivers/acpi/hardware/hwxface.c b/drivers/acpi/hardware/hwxface.c
index b6244a0fcf4c..0601ed711f30 100644
--- a/drivers/acpi/hardware/hwxface.c
+++ b/drivers/acpi/hardware/hwxface.c
@@ -50,6 +50,43 @@ ACPI_MODULE_NAME("hwxface")
 
 /******************************************************************************
  *
+ * FUNCTION:    acpi_reset
+ *
+ * PARAMETERS:  None
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Set reset register in memory or IO space. Note: Does not
+ *              support reset register in PCI config space, this must be
+ *              handled separately.
+ *
+ ******************************************************************************/
+acpi_status acpi_reset(void)
+{
+        struct acpi_generic_address *reset_reg;
+        acpi_status status;
+
+        ACPI_FUNCTION_TRACE(acpi_reset);
+
+        reset_reg = &acpi_gbl_FADT.reset_register;
+
+        /* Check if the reset register is supported */
+
+        if (!(acpi_gbl_FADT.flags & ACPI_FADT_RESET_REGISTER) ||
+            !reset_reg->address) {
+                return_ACPI_STATUS(AE_NOT_EXIST);
+        }
+
+        /* Write the reset value to the reset register */
+
+        status = acpi_write(acpi_gbl_FADT.reset_value, reset_reg);
+        return_ACPI_STATUS(status);
+}
+
+ACPI_EXPORT_SYMBOL(acpi_reset)
+
+/******************************************************************************
+ *
  * FUNCTION:    acpi_read
  *
  * PARAMETERS:  Value               - Where the value is returned
diff --git a/include/acpi/acpixf.h b/include/acpi/acpixf.h
index 030aeb556e6b..b3bceadf6f75 100644
--- a/include/acpi/acpixf.h
+++ b/include/acpi/acpixf.h
@@ -322,6 +322,8 @@ acpi_resource_to_address64(struct acpi_resource *resource,
 /*
  * Hardware (ACPI device) interfaces
  */
+acpi_status acpi_reset(void);
+
 acpi_status acpi_get_register(u32 register_id, u32 * return_value);
 
 acpi_status acpi_get_register_unlocked(u32 register_id, u32 *return_value);