[linux-2.6-block.git] / drivers / acpi / reboot.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;
	}
}
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
4d387043 AD	2
	3	#include <linux/pci.h>
	4	#include <linux/acpi.h>
	5	#include <acpi/reboot.h>
	6
86689776	7	#ifdef CONFIG_PCI
36ad7d2b SK	8	static void acpi_pci_reboot(struct acpi_generic_address *rr, u8 reset_value)
	9	{
	10	unsigned int devfn;
	11	struct pci_bus *bus0;
	12
	13	/* The reset register can only live on bus 0. */
	14	bus0 = pci_find_bus(0, 0);
	15	if (!bus0)
	16	return;
	17	/* Form PCI device/function pair. */
	18	devfn = PCI_DEVFN((rr->address >> 32) & 0xffff,
	19	(rr->address >> 16) & 0xffff);
	20	pr_debug("Resetting with ACPI PCI RESET_REG.\n");
	21	/* Write the value that resets us. */
	22	pci_bus_write_config_byte(bus0, devfn,
	23	(rr->address & 0xffff), reset_value);
	24	}
86689776 SK	25	#else
	26	static inline void acpi_pci_reboot(struct acpi_generic_address *rr,
	27	u8 reset_value)
	28	{
	29	pr_warn_once("PCI configuration space access is not supported\n");
	30	}
	31	#endif
36ad7d2b	32
4d387043 AD	33	void acpi_reboot(void)
	34	{
	35	struct acpi_generic_address *rr;
dd73e722	36	u8 reset_value;
4d387043 AD	37
	38	if (acpi_disabled)
	39	return;
	40
	41	rr = &acpi_gbl_FADT.reset_register;
	42
95cf3e12 MG	43	/* ACPI reset register was only introduced with v2 of the FADT */
	44
	45	if (acpi_gbl_FADT.header.revision < 2)
	46	return;
	47
6734fe57 MG	48	/* Is the reset register supported? The spec says we should be
	49	* checking the bit width and bit offset, but Windows ignores
	50	* these fields */
19244ad0 LT	51	if (!(acpi_gbl_FADT.flags & ACPI_FADT_RESET_REGISTER))
19244ad0 LT	52	return;
4d387043 AD	53
	54	reset_value = acpi_gbl_FADT.reset_value;
	55
	56	/* The reset register can only exist in I/O, Memory or PCI config space
	57	* on a device on bus 0. */
	58	switch (rr->space_id) {
	59	case ACPI_ADR_SPACE_PCI_CONFIG:
36ad7d2b	60	acpi_pci_reboot(rr, reset_value);
4d387043 AD	61	break;
	62
	63	case ACPI_ADR_SPACE_SYSTEM_MEMORY:
	64	case ACPI_ADR_SPACE_SYSTEM_IO:
	65	printk(KERN_DEBUG "ACPI MEMORY or I/O RESET_REG.\n");
2ee62612	66	acpi_reset();
4d387043 AD	67	break;
4d387043 AD	68	}
4d387043	69	}