cregit-Linux how code gets into the kernel

Release 4.11 drivers/power/reset/piix4-poweroff.c

/*
 * Copyright (C) 2016 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/io.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/pm.h>


static struct pci_dev *pm_dev;

static resource_size_t io_offset;


enum piix4_pm_io_reg {
	
PIIX4_FUNC3IO_PMSTS			= 0x00,

#define PIIX4_FUNC3IO_PMSTS_PWRBTN_STS		BIT(8)
	
PIIX4_FUNC3IO_PMCNTRL			= 0x04,

#define PIIX4_FUNC3IO_PMCNTRL_SUS_EN		BIT(13)

#define PIIX4_FUNC3IO_PMCNTRL_SUS_TYP_SOFF	(0x0 << 10)
};


#define PIIX4_SUSPEND_MAGIC			0x00120002


static const int piix4_pm_io_region = PCI_BRIDGE_RESOURCES;


static void piix4_poweroff(void) { int spec_devid; u16 sts; /* Ensure the power button status is clear */ while (1) { sts = inw(io_offset + PIIX4_FUNC3IO_PMSTS); if (!(sts & PIIX4_FUNC3IO_PMSTS_PWRBTN_STS)) break; outw(sts, io_offset + PIIX4_FUNC3IO_PMSTS); } /* Enable entry to suspend */ outw(PIIX4_FUNC3IO_PMCNTRL_SUS_TYP_SOFF | PIIX4_FUNC3IO_PMCNTRL_SUS_EN, 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_dev->bus, spec_devid, 0, PIIX4_SUSPEND_MAGIC); /* Give the system some time to power down, then error */ mdelay(1000); pr_emerg("Unable to poweroff system\n"); }

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Paul Burton106100.00%1100.00%
Total106100.00%1100.00%


static int piix4_poweroff_probe(struct pci_dev *dev, const struct pci_device_id *id) { int res; if (pm_dev) return -EINVAL; /* Request access to the PIIX4 PM IO registers */ res = pci_request_region(dev, piix4_pm_io_region, "PIIX4 PM IO registers"); if (res) { dev_err(&dev->dev, "failed to request PM IO registers: %d\n", res); return res; } pm_dev = dev; io_offset = pci_resource_start(dev, piix4_pm_io_region); pm_power_off = piix4_poweroff; return 0; }

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Paul Burton81100.00%1100.00%
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static void piix4_poweroff_remove(struct pci_dev *dev) { if (pm_power_off == piix4_poweroff) pm_power_off = NULL; pci_release_region(dev, piix4_pm_io_region); pm_dev = NULL; }

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PersonTokensPropCommitsCommitProp
Paul Burton32100.00%1100.00%
Total32100.00%1100.00%

static const struct pci_device_id piix4_poweroff_ids[] = { { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82371AB_3) }, { 0 }, }; static struct pci_driver piix4_poweroff_driver = { .name = "piix4-poweroff", .id_table = piix4_poweroff_ids, .probe = piix4_poweroff_probe, .remove = piix4_poweroff_remove, }; module_pci_driver(piix4_poweroff_driver); MODULE_AUTHOR("Paul Burton <paul.burton@imgtec.com>"); MODULE_LICENSE("GPL");

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Paul Burton345100.00%1100.00%
Total345100.00%1100.00%
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