Hi,

On Mon, Sep 19, 2016 at 10:21:30PM +0100, Paul Burton wrote:
> Add a driver which allows powering off the system via an Intel PIIX4
> southbridge, by entering the PIIX4 SOff state. This is useful on the
> MIPS Malta development board, where it will power down the FPGA based
> board until its ON/NMI button is pressed, or the QEMU implementation of
> the MIPS Malta board where it will cause QEMU to exit.
> 
> Signed-off-by: Paul Burton <paul.bur...@imgtec.com>
> 
> ---
> 
> Changes in v2:
> - Add MODULE_LICENSE
> - Allow non-MIPS builds with COMPILE_TEST
> 
>  drivers/power/reset/Kconfig          |  10 ++++
>  drivers/power/reset/Makefile         |   1 +
>  drivers/power/reset/piix4-poweroff.c | 104 
> +++++++++++++++++++++++++++++++++++
>  3 files changed, 115 insertions(+)
>  create mode 100644 drivers/power/reset/piix4-poweroff.c
> 
> diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
> index c74c3f6..abeb772 100644
> --- a/drivers/power/reset/Kconfig
> +++ b/drivers/power/reset/Kconfig
> @@ -104,6 +104,16 @@ config POWER_RESET_MSM
>       help
>         Power off and restart support for Qualcomm boards.
>  
> +config POWER_RESET_PIIX4_POWEROFF
> +     tristate "Intel PIIX4 power-off driver"
> +     depends on PCI
> +     depends on MIPS || COMPILE_TEST
> +     help
> +       This driver supports powering off a system using the Intel PIIX4
> +       southbridge, for example the MIPS Malta development board. The
> +       southbridge SOff state is entered in response to a request to
> +       power off the system.
> +
>  config POWER_RESET_LTC2952
>       bool "LTC2952 PowerPath power-off driver"
>       depends on OF_GPIO
> diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile
> index 1be307c..11dae3b 100644
> --- a/drivers/power/reset/Makefile
> +++ b/drivers/power/reset/Makefile
> @@ -10,6 +10,7 @@ obj-$(CONFIG_POWER_RESET_GPIO_RESTART) += gpio-restart.o
>  obj-$(CONFIG_POWER_RESET_HISI) += hisi-reboot.o
>  obj-$(CONFIG_POWER_RESET_IMX) += imx-snvs-poweroff.o
>  obj-$(CONFIG_POWER_RESET_MSM) += msm-poweroff.o
> +obj-$(CONFIG_POWER_RESET_PIIX4_POWEROFF) += piix4-poweroff.o
>  obj-$(CONFIG_POWER_RESET_LTC2952) += ltc2952-poweroff.o
>  obj-$(CONFIG_POWER_RESET_QNAP) += qnap-poweroff.o
>  obj-$(CONFIG_POWER_RESET_RESTART) += restart-poweroff.o
> diff --git a/drivers/power/reset/piix4-poweroff.c 
> b/drivers/power/reset/piix4-poweroff.c
> new file mode 100644
> index 0000000..11f0999
> --- /dev/null
> +++ b/drivers/power/reset/piix4-poweroff.c
> @@ -0,0 +1,104 @@
> +/*
> + * Copyright (C) 2016 Imagination Technologies
> + * Author: Paul Burton <paul.bur...@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 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");
> +}
> +
> +static int piix4_poweroff_probe(struct pci_dev *dev,
> +                             const struct pci_device_id *id)
> +{
> +     int res, io_region = PCI_BRIDGE_RESOURCES;

if (pm_dev)
    return -EINVAL;

> +     /* Request access to the PIIX4 PM IO registers */
> +     res = pci_request_region(dev, 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, io_region);
> +     pm_power_off = piix4_poweroff;
> +
> +     return 0;
> +}
> +
> +static void piix4_poweroff_remove(struct pci_dev *dev)
> +{
> +     if (pm_power_off == piix4_poweroff)
> +             pm_power_off = NULL;

pci_release_region()

> +}
> +
> +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.bur...@imgtec.com>");
> +MODULE_LICENSE("GPL");

-- Sebastian

Attachment: signature.asc
Description: PGP signature

Reply via email to