platform:x86: add Intel P-Unit mailbox IPC driver

This driver provides support for P-Unit mailbox IPC on Intel platforms.
The heart of the P-Unit is the Foxton microcontroller and its firmware,
which provide mailbox interface for power management usage.

Signed-off-by: Qipeng Zha <qipeng.zha@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>

3 files changed, 345 insertions, 0 deletions

diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 1089eaa02b00..148ff880d9be 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -944,4 +944,10 @@ config SURFACE_PRO3_BUTTON
 	depends on ACPI && INPUT
 	---help---
 	  This driver handles the power/home/volume buttons on the Microsoft Surface Pro 3 tablet.
+
+config INTEL_PUNIT_IPC
+	tristate "Intel P-Unit IPC Driver"
+	---help---
+	  This driver provides support for Intel P-Unit Mailbox IPC mechanism,
+	  which is used to bridge the communications between kernel and P-Unit.
 endif # X86_PLATFORM_DEVICES
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index 3ca78a3eb6f8..5ee5425fcc1c 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -62,3 +62,4 @@ obj-$(CONFIG_PVPANIC)           += pvpanic.o
 obj-$(CONFIG_ALIENWARE_WMI)	+= alienware-wmi.o
 obj-$(CONFIG_INTEL_PMC_IPC)	+= intel_pmc_ipc.o
 obj-$(CONFIG_SURFACE_PRO3_BUTTON)	+= surfacepro3_button.o
+obj-$(CONFIG_INTEL_PUNIT_IPC)  += intel_punit_ipc.o
diff --git a/drivers/platform/x86/intel_punit_ipc.c b/drivers/platform/x86/intel_punit_ipc.c
new file mode 100644
index 000000000000..16685bc96946
--- /dev/null
+++ b/drivers/platform/x86/intel_punit_ipc.c
@@ -0,0 +1,338 @@
+/*
+ * Driver for the Intel P-Unit Mailbox IPC mechanism
+ *
+ * (C) Copyright 2015 Intel Corporation
+ *
+ * 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.
+ *
+ * The heart of the P-Unit is the Foxton microcontroller and its firmware,
+ * which provide mailbox interface for power management usage.
+ */
+
+#include <linux/module.h>
+#include <linux/acpi.h>
+#include <linux/delay.h>
+#include <linux/bitops.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <asm/intel_punit_ipc.h>
+
+/* IPC Mailbox registers */
+#define OFFSET_DATA_LOW		0x0
+#define OFFSET_DATA_HIGH	0x4
+/* bit field of interface register */
+#define	CMD_RUN			BIT(31)
+#define	CMD_ERRCODE_MASK	GENMASK(7, 0)
+#define	CMD_PARA1_SHIFT		8
+#define	CMD_PARA2_SHIFT		16
+
+#define CMD_TIMEOUT_SECONDS	1
+
+enum {
+	BASE_DATA = 0,
+	BASE_IFACE,
+	BASE_MAX,
+};
+
+typedef struct {
+	struct device *dev;
+	struct mutex lock;
+	int irq;
+	struct completion cmd_complete;
+	/* base of interface and data registers */
+	void __iomem *base[RESERVED_IPC][BASE_MAX];
+	IPC_TYPE type;
+} IPC_DEV;
+
+static IPC_DEV *punit_ipcdev;
+
+static inline u32 ipc_read_status(IPC_DEV *ipcdev, IPC_TYPE type)
+{
+	return readl(ipcdev->base[type][BASE_IFACE]);
+}
+
+static inline void ipc_write_cmd(IPC_DEV *ipcdev, IPC_TYPE type, u32 cmd)
+{
+	writel(cmd, ipcdev->base[type][BASE_IFACE]);
+}
+
+static inline u32 ipc_read_data_low(IPC_DEV *ipcdev, IPC_TYPE type)
+{
+	return readl(ipcdev->base[type][BASE_DATA] + OFFSET_DATA_LOW);
+}
+
+static inline u32 ipc_read_data_high(IPC_DEV *ipcdev, IPC_TYPE type)
+{
+	return readl(ipcdev->base[type][BASE_DATA] + OFFSET_DATA_HIGH);
+}
+
+static inline void ipc_write_data_low(IPC_DEV *ipcdev, IPC_TYPE type, u32 data)
+{
+	writel(data, ipcdev->base[type][BASE_DATA] + OFFSET_DATA_LOW);
+}
+
+static inline void ipc_write_data_high(IPC_DEV *ipcdev, IPC_TYPE type, u32 data)
+{
+	writel(data, ipcdev->base[type][BASE_DATA] + OFFSET_DATA_HIGH);
+}
+
+static const char *ipc_err_string(int error)
+{
+	if (error == IPC_PUNIT_ERR_SUCCESS)
+		return "no error";
+	else if (error == IPC_PUNIT_ERR_INVALID_CMD)
+		return "invalid command";
+	else if (error == IPC_PUNIT_ERR_INVALID_PARAMETER)
+		return "invalid parameter";
+	else if (error == IPC_PUNIT_ERR_CMD_TIMEOUT)
+		return "command timeout";
+	else if (error == IPC_PUNIT_ERR_CMD_LOCKED)
+		return "command locked";
+	else if (error == IPC_PUNIT_ERR_INVALID_VR_ID)
+		return "invalid vr id";
+	else if (error == IPC_PUNIT_ERR_VR_ERR)
+		return "vr error";
+	else
+		return "unknown error";
+}
+
+static int intel_punit_ipc_check_status(IPC_DEV *ipcdev, IPC_TYPE type)
+{
+	int loops = CMD_TIMEOUT_SECONDS * USEC_PER_SEC;
+	int errcode;
+	int status;
+
+	if (ipcdev->irq) {
+		if (!wait_for_completion_timeout(&ipcdev->cmd_complete,
+						 CMD_TIMEOUT_SECONDS * HZ)) {
+			dev_err(ipcdev->dev, "IPC timed out\n");
+			return -ETIMEDOUT;
+		}
+	} else {
+		while ((ipc_read_status(ipcdev, type) & CMD_RUN) && --loops)
+			udelay(1);
+		if (!loops) {
+			dev_err(ipcdev->dev, "IPC timed out\n");
+			return -ETIMEDOUT;
+		}
+	}
+
+	status = ipc_read_status(ipcdev, type);
+	errcode = status & CMD_ERRCODE_MASK;
+	if (errcode) {
+		dev_err(ipcdev->dev, "IPC failed: %s, IPC_STS=0x%x\n",
+			ipc_err_string(errcode), status);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+/**
+ * intel_punit_ipc_simple_command() - Simple IPC command
+ * @cmd:	IPC command code.
+ * @para1:	First 8bit parameter, set 0 if not used.
+ * @para2:	Second 8bit parameter, set 0 if not used.
+ *
+ * Send a IPC command to P-Unit when there is no data transaction
+ *
+ * Return:	IPC error code or 0 on success.
+ */
+int intel_punit_ipc_simple_command(int cmd, int para1, int para2)
+{
+	IPC_DEV *ipcdev = punit_ipcdev;
+	IPC_TYPE type;
+	u32 val;
+	int ret;
+
+	mutex_lock(&ipcdev->lock);
+
+	reinit_completion(&ipcdev->cmd_complete);
+	type = (cmd & IPC_PUNIT_CMD_TYPE_MASK) >> IPC_TYPE_OFFSET;
+
+	val = cmd & ~IPC_PUNIT_CMD_TYPE_MASK;
+	val |= CMD_RUN | para2 << CMD_PARA2_SHIFT | para1 << CMD_PARA1_SHIFT;
+	ipc_write_cmd(ipcdev, type, val);
+	ret = intel_punit_ipc_check_status(ipcdev, type);
+
+	mutex_unlock(&ipcdev->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL(intel_punit_ipc_simple_command);
+
+/**
+ * intel_punit_ipc_command() - IPC command with data and pointers
+ * @cmd:	IPC command code.
+ * @para1:	First 8bit parameter, set 0 if not used.
+ * @para2:	Second 8bit parameter, set 0 if not used.
+ * @in:		Input data, 32bit for BIOS cmd, two 32bit for GTD and ISPD.
+ * @out:	Output data.
+ *
+ * Send a IPC command to P-Unit with data transaction
+ *
+ * Return:	IPC error code or 0 on success.
+ */
+int intel_punit_ipc_command(u32 cmd, u32 para1, u32 para2, u32 *in, u32 *out)
+{
+	IPC_DEV *ipcdev = punit_ipcdev;
+	IPC_TYPE type;
+	u32 val;
+	int ret;
+
+	mutex_lock(&ipcdev->lock);
+
+	reinit_completion(&ipcdev->cmd_complete);
+	type = (cmd & IPC_PUNIT_CMD_TYPE_MASK) >> IPC_TYPE_OFFSET;
+	ipc_write_data_low(ipcdev, type, *in);
+
+	if (type == GTDRIVER_IPC || type == ISPDRIVER_IPC)
+		ipc_write_data_high(ipcdev, type, *++in);
+
+	val = cmd & ~IPC_PUNIT_CMD_TYPE_MASK;
+	val |= CMD_RUN | para2 << CMD_PARA2_SHIFT | para1 << CMD_PARA1_SHIFT;
+	ipc_write_cmd(ipcdev, type, val);
+
+	ret = intel_punit_ipc_check_status(ipcdev, type);
+	if (ret)
+		goto out;
+	*out = ipc_read_data_low(ipcdev, type);
+
+	if (type == GTDRIVER_IPC || type == ISPDRIVER_IPC)
+		*++out = ipc_read_data_high(ipcdev, type);
+
+out:
+	mutex_unlock(&ipcdev->lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(intel_punit_ipc_command);
+
+static irqreturn_t intel_punit_ioc(int irq, void *dev_id)
+{
+	IPC_DEV *ipcdev = dev_id;
+
+	complete(&ipcdev->cmd_complete);
+	return IRQ_HANDLED;
+}
+
+static int intel_punit_get_bars(struct platform_device *pdev)
+{
+	struct resource *res;
+	void __iomem *addr;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	addr = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(addr))
+		return PTR_ERR(addr);
+	punit_ipcdev->base[BIOS_IPC][BASE_DATA] = addr;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	addr = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(addr))
+		return PTR_ERR(addr);
+	punit_ipcdev->base[BIOS_IPC][BASE_IFACE] = addr;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 2);
+	addr = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(addr))
+		return PTR_ERR(addr);
+	punit_ipcdev->base[ISPDRIVER_IPC][BASE_DATA] = addr;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 3);
+	addr = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(addr))
+		return PTR_ERR(addr);
+	punit_ipcdev->base[ISPDRIVER_IPC][BASE_IFACE] = addr;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 4);
+	addr = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(addr))
+		return PTR_ERR(addr);
+	punit_ipcdev->base[GTDRIVER_IPC][BASE_DATA] = addr;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 5);
+	addr = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(addr))
+		return PTR_ERR(addr);
+	punit_ipcdev->base[GTDRIVER_IPC][BASE_IFACE] = addr;
+
+	return 0;
+}
+
+static int intel_punit_ipc_probe(struct platform_device *pdev)
+{
+	int irq, ret;
+
+	punit_ipcdev = devm_kzalloc(&pdev->dev,
+				    sizeof(*punit_ipcdev), GFP_KERNEL);
+	if (!punit_ipcdev)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, punit_ipcdev);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		punit_ipcdev->irq = 0;
+		dev_warn(&pdev->dev, "Invalid IRQ, using polling mode\n");
+	} else {
+		ret = devm_request_irq(&pdev->dev, irq, intel_punit_ioc,
+				       IRQF_NO_SUSPEND, "intel_punit_ipc",
+				       &punit_ipcdev);
+		if (ret) {
+			dev_err(&pdev->dev, "Failed to request irq: %d\n", irq);
+			return ret;
+		}
+		punit_ipcdev->irq = irq;
+	}
+
+	ret = intel_punit_get_bars(pdev);
+	if (ret)
+		goto out;
+
+	punit_ipcdev->dev = &pdev->dev;
+	mutex_init(&punit_ipcdev->lock);
+	init_completion(&punit_ipcdev->cmd_complete);
+
+out:
+	return ret;
+}
+
+static int intel_punit_ipc_remove(struct platform_device *pdev)
+{
+	return 0;
+}
+
+static const struct acpi_device_id punit_ipc_acpi_ids[] = {
+	{ "INT34D4", 0 },
+	{ }
+};
+
+static struct platform_driver intel_punit_ipc_driver = {
+	.probe = intel_punit_ipc_probe,
+	.remove = intel_punit_ipc_remove,
+	.driver = {
+		.name = "intel_punit_ipc",
+		.acpi_match_table = ACPI_PTR(punit_ipc_acpi_ids),
+	},
+};
+
+static int __init intel_punit_ipc_init(void)
+{
+	return platform_driver_register(&intel_punit_ipc_driver);
+}
+
+static void __exit intel_punit_ipc_exit(void)
+{
+	platform_driver_unregister(&intel_punit_ipc_driver);
+}
+
+MODULE_AUTHOR("Zha Qipeng <qipeng.zha@intel.com>");
+MODULE_DESCRIPTION("Intel P-Unit IPC driver");
+MODULE_LICENSE("GPL v2");
+
+/* Some modules are dependent on this, so init earlier */
+fs_initcall(intel_punit_ipc_init);
+module_exit(intel_punit_ipc_exit);