Some peripherals on Baytrail and Cherrytrail platforms signal PME to the
PMC to wakeup the system. When this happens software needs to clear the
PME_B0_STS bit in the GPE0a_STS register to avoid an IRQ storm on IRQ 9.
This is modelled in ACPI through the INT0002 ACPI device.
This commit adds a driver which will bind to that device, call the
ACPI event handler for the wakeup and clear the interrupt source
avoiding the irq storm.
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
drivers/platform/x86/Kconfig | 10 ++
drivers/platform/x86/Makefile | 1 +
drivers/platform/x86/intel_int0002.c | 232 +++++++++++++++++++++++++++++++++++
3 files changed, 243 insertions(+)
create mode 100644 drivers/platform/x86/intel_int0002.c
diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 53afa78..c400e29 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -889,6 +889,16 @@ config INTEL_PMC_CORE
Supported features:
- SLP_S0_RESIDENCY counter.
+config INTEL_INT0002
+ tristate "Intel INT0002 Virtual GPIO ACPI device driver"
+ depends on X86 && ACPI
+ ---help---
+ Some peripherals on Baytrail and Cherrytrail platforms signal
+ PME to the PMC to wakeup the system. When this happens software
+ needs to explictly clear the interrupt source to avoid an IRQ
+ storm on IRQ 9. This is modelled in ACPI through the INT0002
+ ACPI device. This driver implements the clearing of the IRQ.
+
config IBM_RTL
tristate "Device driver to enable PRTL support"
depends on PCI
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index 6731893..de4ffb5 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -51,6 +51,7 @@ obj-$(CONFIG_INTEL_SCU_IPC) += intel_scu_ipc.o
obj-$(CONFIG_INTEL_SCU_IPC_UTIL) += intel_scu_ipcutil.o
obj-$(CONFIG_INTEL_MFLD_THERMAL) += intel_mid_thermal.o
obj-$(CONFIG_INTEL_IPS) += intel_ips.o
+obj-$(CONFIG_INTEL_INT0002) += intel_int0002.o
obj-$(CONFIG_XO1_RFKILL) += xo1-rfkill.o
obj-$(CONFIG_XO15_EBOOK) += xo15-ebook.o
obj-$(CONFIG_IBM_RTL) += ibm_rtl.o
diff --git a/drivers/platform/x86/intel_int0002.c b/drivers/platform/x86/intel_int0002.c
new file mode 100644
index 0000000..76220db
--- /dev/null
+++ b/drivers/platform/x86/intel_int0002.c
@@ -0,0 +1,232 @@
+/*
+ * Intel INT0002 "Virtual GPIO" driver
+ *
+ * Copyright (C) 2017 Hans de Goede <hdegoede@xxxxxxxxxx>
+ *
+ * Loosely based on android x86 kernel code which is:
+ *
+ * Copyright (c) 2014, Intel Corporation.
+ *
+ * Author: Dyut Kumar Sil <dyut.k.sil@xxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Some peripherals on Baytrail and Cherrytrail platforms signal PME to the
+ * PMC to wakeup the system. When this happens software needs to clear the
+ * PME_B0_STS 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.
+ *
+ * This driver will bind to the INT0002 device, call the ACPI event handler
+ * for the wakeup and clear the interrupt source avoiding the irq storm.
+ */
+
+#include <asm/cpu_device_id.h>
+#include <asm/intel-family.h>
+#include <asm/io.h>
+#include <linux/acpi.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/slab.h>
+
+#define GPE0A_PME_STS_BIT 0x2000
+#define GPE0A_PME_EN_BIT 0x2000
+#define GPE0A_STS_PORT 0x420
+#define GPE0A_EN_PORT 0x428
+
+#define ICPU(model) { X86_VENDOR_INTEL, 6, model, X86_FEATURE_ANY, }
+
+static const struct x86_cpu_id int0002_cpu_ids[] = {
+/*
+ * Limit ourselves to Cherry Trail for now, until testing shows we
+ * need to handle the INT0002 device on Baytrail too.
+ * ICPU(INTEL_FAM6_ATOM_SILVERMONT1), * Valleyview, Bay Trail *
+ */
+ ICPU(INTEL_FAM6_ATOM_AIRMONT), /* Braswell, Cherry Trail */
+ {}
+};
+
+struct int0002_data {
+ struct spinlock lock;
+ struct device *dev;
+ const struct x86_cpu_id *cpu_id;
+ acpi_handle handle;
+ char ev_name[5];
+};
+
+static void int0002_irq_enable(struct int0002_data *data, bool enable)
+{
+ unsigned long flags;
+ u32 gpe_en_reg;
+
+ spin_lock_irqsave(&data->lock, flags);
+
+ gpe_en_reg = inl(GPE0A_EN_PORT);
+ if (enable)
+ gpe_en_reg |= GPE0A_PME_EN_BIT;
+ else
+ gpe_en_reg &= ~GPE0A_PME_EN_BIT;
+ outl(gpe_en_reg, GPE0A_EN_PORT);
+
+ spin_unlock_irqrestore(&data->lock, flags);
+}
+
+static irqreturn_t int0002_irq_handler(int irq, void *handler_data)
+{
+ struct int0002_data *data = handler_data;
+ u32 gpe_sts_reg;
+
+ gpe_sts_reg = inl(GPE0A_STS_PORT);
+ if (!(gpe_sts_reg & GPE0A_PME_STS_BIT))
+ return IRQ_NONE;
+
+ int0002_irq_enable(data, false);
+
+ return IRQ_WAKE_THREAD;
+}
+
+static irqreturn_t int0002_irq_thread(int irq, void *handler_data)
+{
+ struct int0002_data *data = handler_data;
+ acpi_status status;
+
+ /* Don't call ACPI event handler on Baytrail? Taken from Android-x86 */
+ if (data->cpu_id->model != INTEL_FAM6_ATOM_SILVERMONT1) {
+ status = acpi_evaluate_object(data->handle, data->ev_name,
+ NULL, NULL);
+ if (ACPI_FAILURE(status))
+ dev_err(data->dev, "Error calling %s\n", data->ev_name);
+ }
+
+ /* Ack and then re-enable IRQ */
+ outl(GPE0A_PME_STS_BIT, GPE0A_STS_PORT);
+ int0002_irq_enable(data, true);
+
+ return IRQ_HANDLED;
+}
+
+static int int0002_probe(struct platform_device *pdev)
+{
+ struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER, NULL };
+ struct device *dev = &pdev->dev;
+ struct int0002_data *data;
+ struct acpi_resource *res;
+ acpi_status status;
+ acpi_handle hdl;
+ int irq, ret;
+
+ data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+ if (!data) {
+ dev_err(dev, "can't allocate memory for int0002\n");
+ return -ENOMEM;
+ }
+
+ spin_lock_init(&data->lock);
+ data->dev = dev;
+
+ /* Menlow has a different INT0002 device? <sigh> */
+ data->cpu_id = x86_match_cpu(int0002_cpu_ids);
+ if (!data->cpu_id)
+ return -ENODEV;
+
+ data->handle = ACPI_HANDLE(dev);
+ if (!data->handle)
+ return -ENODEV;
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0) {
+ dev_err(dev, "Error getting IRQ: %d\n", irq);
+ return irq;
+ }
+
+ status = acpi_get_event_resources(data->handle, &buf);
+ if (ACPI_FAILURE(status)) {
+ dev_err(dev, "Error getting acpi event resources\n");
+ return -ENODEV;
+ }
+
+ /* Find the "GPIO interrupt" event handler to call upon PME */
+ ret = -ENODEV;
+ for (res = buf.pointer;
+ res && (res->type != ACPI_RESOURCE_TYPE_END_TAG);
+ res = ACPI_NEXT_RESOURCE(res)) {
+
+ if (res->type != ACPI_RESOURCE_TYPE_GPIO ||
+ res->data.gpio.connection_type !=
+ ACPI_RESOURCE_GPIO_TYPE_INT)
+ continue;
+
+ snprintf(data->ev_name, sizeof(data->ev_name), "_%c%02X",
+ res->data.gpio.triggering ? 'E' : 'L',
+ res->data.gpio.pin_table[0]);
+
+ status = acpi_get_handle(data->handle, data->ev_name, &hdl);
+ if (ACPI_SUCCESS(status)) {
+ ret = 0;
+ break;
+ }
+ }
+
+ ACPI_FREE(buf.pointer);
+
+ if (ret) {
+ dev_err(dev, "Error could not find event handler\n");
+ return ret;
+ }
+
+ ret = devm_request_threaded_irq(dev, irq,
+ int0002_irq_handler, int0002_irq_thread,
+ IRQF_SHARED, "INT0002", data);
+ if (ret) {
+ dev_err(dev, "Error requesting IRQ %d: %d\n", irq, ret);
+ return ret;
+ }
+
+ int0002_irq_enable(data, true);
+
+ return 0;
+}
+
+static int int0002_runtime_suspend(struct device *dev)
+{
+ return 0;
+}
+
+static int int0002_runtime_resume(struct device *dev)
+{
+ return 0;
+}
+
+static const struct dev_pm_ops int0002_pm_ops = {
+ .runtime_suspend = int0002_runtime_suspend,
+ .runtime_resume = int0002_runtime_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 = "Intel INT0002 Virtual GPIO",
+ .pm = &int0002_pm_ops,
+ .acpi_match_table = ACPI_PTR(int0002_acpi_ids),
+ },
+ .probe = int0002_probe,
+};
+
+module_platform_driver(int0002_driver);
+
+MODULE_AUTHOR("Hans de Goede <hdegoede@xxxxxxxxxx>");
+MODULE_DESCRIPTION("Intel INT0002 Virtual GPIO driver");
+MODULE_LICENSE("GPL");
--
2.9.3
