linux/drivers/acpi/reboot.c
Sinan Kaya 8668977687 ACPI: Allow CONFIG_PCI to be unset for reboot
Make PCI reboot conditional on CONFIG_PCI set on the kernel configuration.

Signed-off-by: Sinan Kaya <okaya@kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-12-20 10:19:49 +01:00

70 lines
1.7 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <linux/pci.h>
#include <linux/acpi.h>
#include <acpi/reboot.h>
#ifdef CONFIG_PCI
static void acpi_pci_reboot(struct acpi_generic_address *rr, u8 reset_value)
{
unsigned int devfn;
struct pci_bus *bus0;
/* 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);
pr_debug("Resetting with ACPI PCI RESET_REG.\n");
/* Write the value that resets us. */
pci_bus_write_config_byte(bus0, devfn,
(rr->address & 0xffff), reset_value);
}
#else
static inline void acpi_pci_reboot(struct acpi_generic_address *rr,
u8 reset_value)
{
pr_warn_once("PCI configuration space access is not supported\n");
}
#endif
void acpi_reboot(void)
{
struct acpi_generic_address *rr;
u8 reset_value;
if (acpi_disabled)
return;
rr = &acpi_gbl_FADT.reset_register;
/* ACPI reset register was only introduced with v2 of the FADT */
if (acpi_gbl_FADT.header.revision < 2)
return;
/* Is the reset register supported? The spec says we should be
* checking the bit width and bit offset, but Windows ignores
* these fields */
if (!(acpi_gbl_FADT.flags & ACPI_FADT_RESET_REGISTER))
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:
acpi_pci_reboot(rr, 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.\n");
acpi_reset();
break;
}
}