1 files changed, 109 insertions, 0 deletions
diff --git a/drivers/power/reset/piix4-poweroff.c b/drivers/power/reset/piix4-poweroff.c
new file mode 100644
index 000000000..7f308292d
--- /dev/null
+++ b/drivers/power/reset/piix4-poweroff.c
@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2016 Imagination Technologies
+ * Author: Paul Burton <paul.burton@mips.com>
+ */
+
+#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");
+}
+
+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;
+}
+
+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;
+}
+
+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@mips.com>");
+MODULE_LICENSE("GPL");