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Subject[PATCH] ACPI: Add reboot mechanism

Add the ability to reset the machine using the RESET_REG in ACPI's FADT table.

Signed-off-by: Aaron Durbin <adurbin@google.com>
---
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index d4336f1..c9906a5 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -21,7 +21,7 @@ obj-$(CONFIG_X86) += blacklist.o
#
# ACPI Core Subsystem (Interpreter)
#
-obj-y += osl.o utils.o \
+obj-y += osl.o utils.o reboot.o \
dispatcher/ events/ executer/ hardware/ \
namespace/ parser/ resources/ tables/ \
utilities/
diff --git a/drivers/acpi/reboot.c b/drivers/acpi/reboot.c
new file mode 100644
index 0000000..4bb4d3e
--- /dev/null
+++ b/drivers/acpi/reboot.c
@@ -0,0 +1,45 @@
+
+#include <linux/pci.h>
+#include <acpi/acpi.h>
+
+void acpi_reboot(void)
+{
+ struct acpi_generic_address *rr;
+ struct pci_bus *bus0;
+ u8 reset_value;
+ unsigned int devfn;
+
+ rr = &acpi_gbl_FADT.reset_register;
+
+ /* Is the reset register supported? */
+ if (!(acpi_gbl_FADT.flags & ACPI_FADT_RESET_REGISTER) ||
+ rr->bit_width != 8 || rr->bit_offset != 0)
+ return;
+
+ reset_value = acpi_gbl_FADT.reset_value;
+
+ /* The reset register can only exist in I/O, Memory or PCI config space
+ * on a device on bus 0. */
+ switch (rr->space_id) {
+ case ACPI_ADR_SPACE_PCI_CONFIG:
+ /* The reset register can only live on bus 0. */
+ bus0 = pci_find_bus(0, 0);
+ if (!bus0)
+ return;
+ /* Form PCI device/function pair. */
+ devfn = PCI_DEVFN((rr->address >> 32) & 0xffff,
+ (rr->address >> 16) & 0xffff);
+ printk(KERN_DEBUG "Resetting with ACPI PCI RESET_REG.");
+ /* Write the value that resets us. */
+ pci_bus_write_config_byte(bus0, devfn,
+ (rr->address & 0xffff), reset_value);
+ break;
+
+ case ACPI_ADR_SPACE_SYSTEM_MEMORY:
+ case ACPI_ADR_SPACE_SYSTEM_IO:
+ printk(KERN_DEBUG "ACPI MEMORY or I/O RESET_REG.");
+ acpi_hw_low_level_write(8, reset_value, rr);
+ break;
+ }
+}
+
diff --git a/include/acpi/reboot.h b/include/acpi/reboot.h
new file mode 100644
index 0000000..1d8da79
--- /dev/null
+++ b/include/acpi/reboot.h
@@ -0,0 +1,10 @@
+#ifndef __ACPI_REBOOT_H
+#define __ACPI_REBOOT_H
+
+#ifdef CONFIG_ACPI
+extern void acpi_reboot(void);
+#else
+#define acpi_reboot()
+#endif
+
+#endif
-
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