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Commit b6911bba authored by Paul Burton's avatar Paul Burton Committed by Ralf Baechle
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MIPS: Malta: add suspend state entry code 



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: default avatarPaul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6905/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent 643c5705

arch/mips/Kconfig

+6 −0
Original line number Diff line number Diff line
@@ -1671,6 +1671,12 @@ config SYS_HAS_CPU_XLR 
config SYS_HAS_CPU_XLP

	bool



config MIPS_MALTA_PM

	depends on MIPS_MALTA

	depends on PCI

	bool

	default y



#

# CPU may reorder R->R, R->W, W->R, W->W

# Reordering beyond LL and SC is handled in WEAK_REORDERING_BEYOND_LLSC

arch/mips/include/asm/mach-malta/malta-pm.h

0 → 100644
+37 −0
Original line number Diff line number Diff line 
/*

 * 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.

 */



#ifndef __ASM_MIPS_MACH_MALTA_PM_H__

#define __ASM_MIPS_MACH_MALTA_PM_H__



#include <asm/mips-boards/piix4.h>



#ifdef CONFIG_MIPS_MALTA_PM



/**

 * mips_pm_suspend - enter a suspend state

 * @state: the state to enter, one of PIIX4_FUNC3IO_PMCNTRL_SUS_TYP_*

 *

 * Enters a suspend state via the Malta's PIIX4. If the state to be entered

 * is one which loses context (eg. SOFF) then this function will never

 * return.

 */

extern int mips_pm_suspend(unsigned state);



#else /* !CONFIG_MIPS_MALTA_PM */



static inline int mips_pm_suspend(unsigned state)

{

	return -EINVAL;

}



#endif /* !CONFIG_MIPS_MALTA_PM */



#endif /* __ASM_MIPS_MACH_MALTA_PM_H__ */

arch/mips/mti-malta/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -8,3 +8,5 @@ 
obj-y				:= malta-amon.o malta-display.o malta-init.o \

				   malta-int.o malta-memory.o malta-platform.o \

				   malta-reset.o malta-setup.o malta-time.o



obj-$(CONFIG_MIPS_MALTA_PM)	+= malta-pm.o

arch/mips/mti-malta/malta-pm.c

0 → 100644
+96 −0
Original line number Diff line number Diff line 
/*

 * 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);