1 files changed, 283 insertions, 0 deletions
diff --git a/drivers/platform/x86/intel/int0002_vgpio.c b/drivers/platform/x86/intel/int0002_vgpio.c
new file mode 100644
index 000000000..97cfbc520
--- /dev/null
+++ b/drivers/platform/x86/intel/int0002_vgpio.c
@@ -0,0 +1,283 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Intel INT0002 "Virtual GPIO" driver
+ *
+ * Copyright (C) 2017 Hans de Goede <hdegoede@redhat.com>
+ *
+ * Loosely based on android x86 kernel code which is:
+ *
+ * Copyright (c) 2014, Intel Corporation.
+ *
+ * Author: Dyut Kumar Sil <dyut.k.sil@intel.com>
+ *
+ * Some peripherals on Bay Trail and Cherry Trail platforms signal a Power
+ * Management Event (PME) to the Power Management Controller (PMC) to wakeup
+ * the system. When this happens software needs to clear the PME bus 0 status
+ * bit in the GPE0a_STS register to avoid an IRQ storm on IRQ 9.
+ *
+ * This is modelled in ACPI through the INT0002 ACPI device, which is
+ * called a "Virtual GPIO controller" in ACPI because it defines the event
+ * handler to call when the PME triggers through _AEI and _L02 / _E02
+ * methods as would be done for a real GPIO interrupt in ACPI. Note this
+ * is a hack to define an AML event handler for the PME while using existing
+ * ACPI mechanisms, this is not a real GPIO at all.
+ *
+ * This driver will bind to the INT0002 device, and register as a GPIO
+ * controller, letting gpiolib-acpi.c call the _L02 handler as it would
+ * for a real GPIO controller.
+ */
+
+#include <linux/acpi.h>
+#include <linux/bitmap.h>
+#include <linux/gpio/driver.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_data/x86/soc.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/suspend.h>
+
+#define DRV_NAME			"INT0002 Virtual GPIO"
+
+/* For some reason the virtual GPIO pin tied to the GPE is numbered pin 2 */
+#define GPE0A_PME_B0_VIRT_GPIO_PIN	2
+
+#define GPE0A_PME_B0_STS_BIT		BIT(13)
+#define GPE0A_PME_B0_EN_BIT		BIT(13)
+#define GPE0A_STS_PORT			0x420
+#define GPE0A_EN_PORT			0x428
+
+struct int0002_data {
+	struct gpio_chip chip;
+	int parent_irq;
+	int wake_enable_count;
+};
+
+/*
+ * As this is not a real GPIO at all, but just a hack to model an event in
+ * ACPI the get / set functions are dummy functions.
+ */
+
+static int int0002_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+	return 0;
+}
+
+static void int0002_gpio_set(struct gpio_chip *chip, unsigned int offset,
+			     int value)
+{
+}
+
+static int int0002_gpio_direction_output(struct gpio_chip *chip,
+					 unsigned int offset, int value)
+{
+	return 0;
+}
+
+static void int0002_irq_ack(struct irq_data *data)
+{
+	outl(GPE0A_PME_B0_STS_BIT, GPE0A_STS_PORT);
+}
+
+static void int0002_irq_unmask(struct irq_data *data)
+{
+	u32 gpe_en_reg;
+
+	gpe_en_reg = inl(GPE0A_EN_PORT);
+	gpe_en_reg |= GPE0A_PME_B0_EN_BIT;
+	outl(gpe_en_reg, GPE0A_EN_PORT);
+}
+
+static void int0002_irq_mask(struct irq_data *data)
+{
+	u32 gpe_en_reg;
+
+	gpe_en_reg = inl(GPE0A_EN_PORT);
+	gpe_en_reg &= ~GPE0A_PME_B0_EN_BIT;
+	outl(gpe_en_reg, GPE0A_EN_PORT);
+}
+
+static int int0002_irq_set_wake(struct irq_data *data, unsigned int on)
+{
+	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
+	struct int0002_data *int0002 = container_of(chip, struct int0002_data, chip);
+
+	/*
+	 * Applying of the wakeup flag to our parent IRQ is delayed till system
+	 * suspend, because we only want to do this when using s2idle.
+	 */
+	if (on)
+		int0002->wake_enable_count++;
+	else
+		int0002->wake_enable_count--;
+
+	return 0;
+}
+
+static irqreturn_t int0002_irq(int irq, void *data)
+{
+	struct gpio_chip *chip = data;
+	u32 gpe_sts_reg;
+
+	gpe_sts_reg = inl(GPE0A_STS_PORT);
+	if (!(gpe_sts_reg & GPE0A_PME_B0_STS_BIT))
+		return IRQ_NONE;
+
+	generic_handle_domain_irq_safe(chip->irq.domain, GPE0A_PME_B0_VIRT_GPIO_PIN);
+
+	pm_wakeup_hard_event(chip->parent);
+
+	return IRQ_HANDLED;
+}
+
+static bool int0002_check_wake(void *data)
+{
+	u32 gpe_sts_reg;
+
+	gpe_sts_reg = inl(GPE0A_STS_PORT);
+	return (gpe_sts_reg & GPE0A_PME_B0_STS_BIT);
+}
+
+static struct irq_chip int0002_irqchip = {
+	.name			= DRV_NAME,
+	.irq_ack		= int0002_irq_ack,
+	.irq_mask		= int0002_irq_mask,
+	.irq_unmask		= int0002_irq_unmask,
+	.irq_set_wake		= int0002_irq_set_wake,
+};
+
+static void int0002_init_irq_valid_mask(struct gpio_chip *chip,
+					unsigned long *valid_mask,
+					unsigned int ngpios)
+{
+	bitmap_clear(valid_mask, 0, GPE0A_PME_B0_VIRT_GPIO_PIN);
+}
+
+static int int0002_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct int0002_data *int0002;
+	struct gpio_irq_chip *girq;
+	struct gpio_chip *chip;
+	int irq, ret;
+
+	/* Menlow has a different INT0002 device? <sigh> */
+	if (!soc_intel_is_byt() && !soc_intel_is_cht())
+		return -ENODEV;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	int0002 = devm_kzalloc(dev, sizeof(*int0002), GFP_KERNEL);
+	if (!int0002)
+		return -ENOMEM;
+
+	int0002->parent_irq = irq;
+
+	chip = &int0002->chip;
+	chip->label = DRV_NAME;
+	chip->parent = dev;
+	chip->owner = THIS_MODULE;
+	chip->get = int0002_gpio_get;
+	chip->set = int0002_gpio_set;
+	chip->direction_input = int0002_gpio_get;
+	chip->direction_output = int0002_gpio_direction_output;
+	chip->base = -1;
+	chip->ngpio = GPE0A_PME_B0_VIRT_GPIO_PIN + 1;
+	chip->irq.init_valid_mask = int0002_init_irq_valid_mask;
+
+	/*
+	 * We directly request the irq here instead of passing a flow-handler
+	 * to gpiochip_set_chained_irqchip, because the irq is shared.
+	 * FIXME: augment this if we managed to pull handling of shared
+	 * IRQs into gpiolib.
+	 */
+	ret = devm_request_irq(dev, irq, int0002_irq,
+			       IRQF_SHARED, "INT0002", chip);
+	if (ret) {
+		dev_err(dev, "Error requesting IRQ %d: %d\n", irq, ret);
+		return ret;
+	}
+
+	girq = &chip->irq;
+	girq->chip = &int0002_irqchip;
+	/* This let us handle the parent IRQ in the driver */
+	girq->parent_handler = NULL;
+	girq->num_parents = 0;
+	girq->parents = NULL;
+	girq->default_type = IRQ_TYPE_NONE;
+	girq->handler = handle_edge_irq;
+
+	ret = devm_gpiochip_add_data(dev, chip, NULL);
+	if (ret) {
+		dev_err(dev, "Error adding gpio chip: %d\n", ret);
+		return ret;
+	}
+
+	acpi_register_wakeup_handler(irq, int0002_check_wake, NULL);
+	device_init_wakeup(dev, true);
+	dev_set_drvdata(dev, int0002);
+	return 0;
+}
+
+static int int0002_remove(struct platform_device *pdev)
+{
+	device_init_wakeup(&pdev->dev, false);
+	acpi_unregister_wakeup_handler(int0002_check_wake, NULL);
+	return 0;
+}
+
+static int int0002_suspend(struct device *dev)
+{
+	struct int0002_data *int0002 = dev_get_drvdata(dev);
+
+	/*
+	 * The INT0002 parent IRQ is often shared with the ACPI GPE IRQ, don't
+	 * muck with it when firmware based suspend is used, otherwise we may
+	 * cause spurious wakeups from firmware managed suspend.
+	 */
+	if (!pm_suspend_via_firmware() && int0002->wake_enable_count)
+		enable_irq_wake(int0002->parent_irq);
+
+	return 0;
+}
+
+static int int0002_resume(struct device *dev)
+{
+	struct int0002_data *int0002 = dev_get_drvdata(dev);
+
+	if (!pm_suspend_via_firmware() && int0002->wake_enable_count)
+		disable_irq_wake(int0002->parent_irq);
+
+	return 0;
+}
+
+static const struct dev_pm_ops int0002_pm_ops = {
+	.suspend = int0002_suspend,
+	.resume = int0002_resume,
+};
+
+static const struct acpi_device_id int0002_acpi_ids[] = {
+	{ "INT0002", 0 },
+	{ },
+};
+MODULE_DEVICE_TABLE(acpi, int0002_acpi_ids);
+
+static struct platform_driver int0002_driver = {
+	.driver = {
+		.name			= DRV_NAME,
+		.acpi_match_table	= int0002_acpi_ids,
+		.pm			= &int0002_pm_ops,
+	},
+	.probe	= int0002_probe,
+	.remove	= int0002_remove,
+};
+
+module_platform_driver(int0002_driver);
+
+MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
+MODULE_DESCRIPTION("Intel INT0002 Virtual GPIO driver");
+MODULE_LICENSE("GPL v2");