mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-11 12:28:41 +08:00
b6911bba59
This patch introduces code which will enter a suspend state via the PIIX4. This can only be done when PCI support is enabled since it requires access to PCI I/O space and the generation of a special cycle on the PCI bus. In cases where PCI is disabled the mips_pm_suspend function will simply always return an error. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/6905/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
97 lines
2.4 KiB
C
97 lines
2.4 KiB
C
/*
|
|
* Copyright (C) 2014 Imagination Technologies
|
|
* Author: Paul Burton <paul.burton@imgtec.com>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify it
|
|
* under the terms of the GNU General Public License as published by the
|
|
* Free Software Foundation; either version 2 of the License, or (at your
|
|
* option) any later version.
|
|
*/
|
|
|
|
#include <linux/delay.h>
|
|
#include <linux/init.h>
|
|
#include <linux/io.h>
|
|
#include <linux/pci.h>
|
|
|
|
#include <asm/mach-malta/malta-pm.h>
|
|
|
|
static struct pci_bus *pm_pci_bus;
|
|
static resource_size_t pm_io_offset;
|
|
|
|
int mips_pm_suspend(unsigned state)
|
|
{
|
|
int spec_devid;
|
|
u16 sts;
|
|
|
|
if (!pm_pci_bus || !pm_io_offset)
|
|
return -ENODEV;
|
|
|
|
/* Ensure the power button status is clear */
|
|
while (1) {
|
|
sts = inw(pm_io_offset + PIIX4_FUNC3IO_PMSTS);
|
|
if (!(sts & PIIX4_FUNC3IO_PMSTS_PWRBTN_STS))
|
|
break;
|
|
outw(sts, pm_io_offset + PIIX4_FUNC3IO_PMSTS);
|
|
}
|
|
|
|
/* Enable entry to suspend */
|
|
outw(state | PIIX4_FUNC3IO_PMCNTRL_SUS_EN,
|
|
pm_io_offset + PIIX4_FUNC3IO_PMCNTRL);
|
|
|
|
/* If the special cycle occurs too soon this doesn't work... */
|
|
mdelay(10);
|
|
|
|
/*
|
|
* The PIIX4 will enter the suspend state only after seeing a special
|
|
* cycle with the correct magic data on the PCI bus. Generate that
|
|
* cycle now.
|
|
*/
|
|
spec_devid = PCI_DEVID(0, PCI_DEVFN(0x1f, 0x7));
|
|
pci_bus_write_config_dword(pm_pci_bus, spec_devid, 0,
|
|
PIIX4_SUSPEND_MAGIC);
|
|
|
|
/* Give the system some time to power down */
|
|
mdelay(1000);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int __init malta_pm_setup(void)
|
|
{
|
|
struct pci_dev *dev;
|
|
int res, io_region = PCI_BRIDGE_RESOURCES;
|
|
|
|
/* Find a reference to the PCI bus */
|
|
pm_pci_bus = pci_find_next_bus(NULL);
|
|
if (!pm_pci_bus) {
|
|
pr_warn("malta-pm: failed to find reference to PCI bus\n");
|
|
return -ENODEV;
|
|
}
|
|
|
|
/* Find the PIIX4 PM device */
|
|
dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
|
|
PCI_DEVICE_ID_INTEL_82371AB_3, PCI_ANY_ID,
|
|
PCI_ANY_ID, NULL);
|
|
if (!dev) {
|
|
pr_warn("malta-pm: failed to find PIIX4 PM\n");
|
|
return -ENODEV;
|
|
}
|
|
|
|
/* Request access to the PIIX4 PM IO registers */
|
|
res = pci_request_region(dev, io_region, "PIIX4 PM IO registers");
|
|
if (res) {
|
|
pr_warn("malta-pm: failed to request PM IO registers (%d)\n",
|
|
res);
|
|
pci_dev_put(dev);
|
|
return -ENODEV;
|
|
}
|
|
|
|
/* Find the offset to the PIIX4 PM IO registers */
|
|
pm_io_offset = pci_resource_start(dev, io_region);
|
|
|
|
pci_dev_put(dev);
|
|
return 0;
|
|
}
|
|
|
|
late_initcall(malta_pm_setup);
|