Merge branch 'acpi-pfrut'

Merge support for the Platform Firmware Runtime Update and Telemetry
interface based on ACPI.

The interface provided here allows updating certain pieces of the
platform firmware without restarting the system and collecting
platform firmware telemetry data.

This also includes a utility for accesing the new interface from user
space.

* acpi-pfrut:
  ACPI: pfr_telemetry: Fix info leak in pfrt_log_ioctl()
  ACPI: pfr_update: Fix return value check in pfru_write()
  ACPI: tools: Introduce utility for firmware updates/telemetry
  ACPI: Introduce Platform Firmware Runtime Telemetry driver
  ACPI: Introduce Platform Firmware Runtime Update device driver
  efi: Introduce EFI_FIRMWARE_MANAGEMENT_CAPSULE_HEADER and corresponding structures

4 files changed, 1033 insertions, 0 deletions

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 60b5424bd318..8cdc7860b6e6 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -517,6 +517,28 @@ config ACPI_CONFIGFS
 	  userspace. The configurable ACPI groups will be visible under
 	  /config/acpi, assuming configfs is mounted under /config.
 
+config ACPI_PFRUT
+	tristate "ACPI Platform Firmware Runtime Update and Telemetry"
+	depends on 64BIT
+	help
+	  This mechanism allows certain pieces of the platform firmware
+	  to be updated on the fly while the system is running (runtime)
+	  without the need to restart it, which is key in the cases when
+	  the system needs to be available 100% of the time and it cannot
+	  afford the downtime related to restarting it, or when the work
+	  carried out by the system is particularly important, so it cannot
+	  be interrupted, and it is not practical to wait until it is complete.
+
+	  The existing firmware code can be modified (driver update) or
+	  extended by adding new code to the firmware (code injection).
+
+	  Besides, the telemetry driver allows user space to fetch telemetry
+	  data from the firmware with the help of the Platform Firmware Runtime
+	  Telemetry interface.
+
+	  To compile the drivers as modules, choose M here:
+	  the modules will be called pfr_update and pfr_telemetry.
+
 if ARM64
 source "drivers/acpi/arm64/Kconfig"
 
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 08c2d985c57c..f47032769f69 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -103,6 +103,7 @@ obj-$(CONFIG_ACPI_CPPC_LIB)	+= cppc_acpi.o
 obj-$(CONFIG_ACPI_SPCR_TABLE)	+= spcr.o
 obj-$(CONFIG_ACPI_DEBUGGER_USER) += acpi_dbg.o
 obj-$(CONFIG_ACPI_PPTT) 	+= pptt.o
+obj-$(CONFIG_ACPI_PFRUT)	+= pfr_update.o pfr_telemetry.o
 
 # processor has its own "processor." module_param namespace
 processor-y			:= processor_driver.o
diff --git a/drivers/acpi/pfr_telemetry.c b/drivers/acpi/pfr_telemetry.c
new file mode 100644
index 000000000000..9abf350bd7a5
--- /dev/null
+++ b/drivers/acpi/pfr_telemetry.c
@@ -0,0 +1,435 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ACPI Platform Firmware Runtime Telemetry driver
+ *
+ * Copyright (C) 2021 Intel Corporation
+ * Author: Chen Yu <yu.c.chen@intel.com>
+ *
+ * This driver allows user space to fetch telemetry data from the
+ * firmware with the help of the Platform Firmware Runtime Telemetry
+ * interface.
+ */
+#include <linux/acpi.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/platform_device.h>
+#include <linux/string.h>
+#include <linux/uaccess.h>
+#include <linux/uio.h>
+#include <linux/uuid.h>
+
+#include <uapi/linux/pfrut.h>
+
+#define PFRT_LOG_EXEC_IDX	0
+#define PFRT_LOG_HISTORY_IDX	1
+
+#define PFRT_LOG_ERR		0
+#define PFRT_LOG_WARN	1
+#define PFRT_LOG_INFO	2
+#define PFRT_LOG_VERB	4
+
+#define PFRT_FUNC_SET_LEV		1
+#define PFRT_FUNC_GET_LEV		2
+#define PFRT_FUNC_GET_DATA		3
+
+#define PFRT_REVID_1		1
+#define PFRT_REVID_2		2
+#define PFRT_DEFAULT_REV_ID	PFRT_REVID_1
+
+enum log_index {
+	LOG_STATUS_IDX = 0,
+	LOG_EXT_STATUS_IDX = 1,
+	LOG_MAX_SZ_IDX = 2,
+	LOG_CHUNK1_LO_IDX = 3,
+	LOG_CHUNK1_HI_IDX = 4,
+	LOG_CHUNK1_SZ_IDX = 5,
+	LOG_CHUNK2_LO_IDX = 6,
+	LOG_CHUNK2_HI_IDX = 7,
+	LOG_CHUNK2_SZ_IDX = 8,
+	LOG_ROLLOVER_CNT_IDX = 9,
+	LOG_RESET_CNT_IDX = 10,
+	LOG_NR_IDX
+};
+
+struct pfrt_log_device {
+	int index;
+	struct pfrt_log_info info;
+	struct device *parent_dev;
+	struct miscdevice miscdev;
+};
+
+/* pfrt_guid is the parameter for _DSM method */
+static const guid_t pfrt_log_guid =
+	GUID_INIT(0x75191659, 0x8178, 0x4D9D, 0xB8, 0x8F, 0xAC, 0x5E,
+		  0x5E, 0x93, 0xE8, 0xBF);
+
+static DEFINE_IDA(pfrt_log_ida);
+
+static inline struct pfrt_log_device *to_pfrt_log_dev(struct file *file)
+{
+	return container_of(file->private_data, struct pfrt_log_device, miscdev);
+}
+
+static int get_pfrt_log_data_info(struct pfrt_log_data_info *data_info,
+				  struct pfrt_log_device *pfrt_log_dev)
+{
+	acpi_handle handle = ACPI_HANDLE(pfrt_log_dev->parent_dev);
+	union acpi_object *out_obj, in_obj, in_buf;
+	int ret = -EBUSY;
+
+	memset(data_info, 0, sizeof(*data_info));
+	memset(&in_obj, 0, sizeof(in_obj));
+	memset(&in_buf, 0, sizeof(in_buf));
+	in_obj.type = ACPI_TYPE_PACKAGE;
+	in_obj.package.count = 1;
+	in_obj.package.elements = &in_buf;
+	in_buf.type = ACPI_TYPE_INTEGER;
+	in_buf.integer.value = pfrt_log_dev->info.log_type;
+
+	out_obj = acpi_evaluate_dsm_typed(handle, &pfrt_log_guid,
+					  pfrt_log_dev->info.log_revid, PFRT_FUNC_GET_DATA,
+					  &in_obj, ACPI_TYPE_PACKAGE);
+	if (!out_obj)
+		return -EINVAL;
+
+	if (out_obj->package.count < LOG_NR_IDX ||
+	    out_obj->package.elements[LOG_STATUS_IDX].type != ACPI_TYPE_INTEGER ||
+	    out_obj->package.elements[LOG_EXT_STATUS_IDX].type != ACPI_TYPE_INTEGER ||
+	    out_obj->package.elements[LOG_MAX_SZ_IDX].type != ACPI_TYPE_INTEGER ||
+	    out_obj->package.elements[LOG_CHUNK1_LO_IDX].type != ACPI_TYPE_INTEGER ||
+	    out_obj->package.elements[LOG_CHUNK1_HI_IDX].type != ACPI_TYPE_INTEGER ||
+	    out_obj->package.elements[LOG_CHUNK1_SZ_IDX].type != ACPI_TYPE_INTEGER ||
+	    out_obj->package.elements[LOG_CHUNK2_LO_IDX].type != ACPI_TYPE_INTEGER ||
+	    out_obj->package.elements[LOG_CHUNK2_HI_IDX].type != ACPI_TYPE_INTEGER ||
+	    out_obj->package.elements[LOG_CHUNK2_SZ_IDX].type != ACPI_TYPE_INTEGER ||
+	    out_obj->package.elements[LOG_ROLLOVER_CNT_IDX].type != ACPI_TYPE_INTEGER ||
+	    out_obj->package.elements[LOG_RESET_CNT_IDX].type != ACPI_TYPE_INTEGER)
+		goto free_acpi_buffer;
+
+	data_info->status = out_obj->package.elements[LOG_STATUS_IDX].integer.value;
+	data_info->ext_status =
+		out_obj->package.elements[LOG_EXT_STATUS_IDX].integer.value;
+	if (data_info->status != DSM_SUCCEED) {
+		dev_dbg(pfrt_log_dev->parent_dev, "Error Status:%d\n", data_info->status);
+		dev_dbg(pfrt_log_dev->parent_dev, "Error Extend Status:%d\n",
+			data_info->ext_status);
+		goto free_acpi_buffer;
+	}
+
+	data_info->max_data_size =
+		out_obj->package.elements[LOG_MAX_SZ_IDX].integer.value;
+	data_info->chunk1_addr_lo =
+		out_obj->package.elements[LOG_CHUNK1_LO_IDX].integer.value;
+	data_info->chunk1_addr_hi =
+		out_obj->package.elements[LOG_CHUNK1_HI_IDX].integer.value;
+	data_info->chunk1_size =
+		out_obj->package.elements[LOG_CHUNK1_SZ_IDX].integer.value;
+	data_info->chunk2_addr_lo =
+		out_obj->package.elements[LOG_CHUNK2_LO_IDX].integer.value;
+	data_info->chunk2_addr_hi =
+		out_obj->package.elements[LOG_CHUNK2_HI_IDX].integer.value;
+	data_info->chunk2_size =
+		out_obj->package.elements[LOG_CHUNK2_SZ_IDX].integer.value;
+	data_info->rollover_cnt =
+		out_obj->package.elements[LOG_ROLLOVER_CNT_IDX].integer.value;
+	data_info->reset_cnt =
+		out_obj->package.elements[LOG_RESET_CNT_IDX].integer.value;
+
+	ret = 0;
+
+free_acpi_buffer:
+	kfree(out_obj);
+
+	return ret;
+}
+
+static int set_pfrt_log_level(int level, struct pfrt_log_device *pfrt_log_dev)
+{
+	acpi_handle handle = ACPI_HANDLE(pfrt_log_dev->parent_dev);
+	union acpi_object *out_obj, *obj, in_obj, in_buf;
+	enum pfru_dsm_status status, ext_status;
+	int ret = 0;
+
+	memset(&in_obj, 0, sizeof(in_obj));
+	memset(&in_buf, 0, sizeof(in_buf));
+	in_obj.type = ACPI_TYPE_PACKAGE;
+	in_obj.package.count = 1;
+	in_obj.package.elements = &in_buf;
+	in_buf.type = ACPI_TYPE_INTEGER;
+	in_buf.integer.value = level;
+
+	out_obj = acpi_evaluate_dsm_typed(handle, &pfrt_log_guid,
+					  pfrt_log_dev->info.log_revid, PFRT_FUNC_SET_LEV,
+					  &in_obj, ACPI_TYPE_PACKAGE);
+	if (!out_obj)
+		return -EINVAL;
+
+	obj = &out_obj->package.elements[0];
+	status = obj->integer.value;
+	if (status != DSM_SUCCEED) {
+		obj = &out_obj->package.elements[1];
+		ext_status = obj->integer.value;
+		dev_dbg(pfrt_log_dev->parent_dev, "Error Status:%d\n", status);
+		dev_dbg(pfrt_log_dev->parent_dev, "Error Extend Status:%d\n", ext_status);
+		ret = -EBUSY;
+	}
+
+	kfree(out_obj);
+
+	return ret;
+}
+
+static int get_pfrt_log_level(struct pfrt_log_device *pfrt_log_dev)
+{
+	acpi_handle handle = ACPI_HANDLE(pfrt_log_dev->parent_dev);
+	union acpi_object *out_obj, *obj;
+	enum pfru_dsm_status status, ext_status;
+	int ret = -EBUSY;
+
+	out_obj = acpi_evaluate_dsm_typed(handle, &pfrt_log_guid,
+					  pfrt_log_dev->info.log_revid, PFRT_FUNC_GET_LEV,
+					  NULL, ACPI_TYPE_PACKAGE);
+	if (!out_obj)
+		return -EINVAL;
+
+	obj = &out_obj->package.elements[0];
+	if (obj->type != ACPI_TYPE_INTEGER)
+		goto free_acpi_buffer;
+
+	status = obj->integer.value;
+	if (status != DSM_SUCCEED) {
+		obj = &out_obj->package.elements[1];
+		ext_status = obj->integer.value;
+		dev_dbg(pfrt_log_dev->parent_dev, "Error Status:%d\n", status);
+		dev_dbg(pfrt_log_dev->parent_dev, "Error Extend Status:%d\n", ext_status);
+		goto free_acpi_buffer;
+	}
+
+	obj = &out_obj->package.elements[2];
+	if (obj->type != ACPI_TYPE_INTEGER)
+		goto free_acpi_buffer;
+
+	ret = obj->integer.value;
+
+free_acpi_buffer:
+	kfree(out_obj);
+
+	return ret;
+}
+
+static int valid_log_level(u32 level)
+{
+	return level == PFRT_LOG_ERR || level == PFRT_LOG_WARN ||
+	       level == PFRT_LOG_INFO || level == PFRT_LOG_VERB;
+}
+
+static int valid_log_type(u32 type)
+{
+	return type == PFRT_LOG_EXEC_IDX || type == PFRT_LOG_HISTORY_IDX;
+}
+
+static inline int valid_log_revid(u32 id)
+{
+	return id == PFRT_REVID_1 || id == PFRT_REVID_2;
+}
+
+static long pfrt_log_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct pfrt_log_device *pfrt_log_dev = to_pfrt_log_dev(file);
+	struct pfrt_log_data_info data_info;
+	struct pfrt_log_info info;
+	void __user *p;
+	int ret = 0;
+
+	p = (void __user *)arg;
+
+	switch (cmd) {
+	case PFRT_LOG_IOC_SET_INFO:
+		if (copy_from_user(&info, p, sizeof(info)))
+			return -EFAULT;
+
+		if (valid_log_revid(info.log_revid))
+			pfrt_log_dev->info.log_revid = info.log_revid;
+
+		if (valid_log_level(info.log_level)) {
+			ret = set_pfrt_log_level(info.log_level, pfrt_log_dev);
+			if (ret < 0)
+				return ret;
+
+			pfrt_log_dev->info.log_level = info.log_level;
+		}
+
+		if (valid_log_type(info.log_type))
+			pfrt_log_dev->info.log_type = info.log_type;
+
+		return 0;
+
+	case PFRT_LOG_IOC_GET_INFO:
+		info.log_level = get_pfrt_log_level(pfrt_log_dev);
+		if (ret < 0)
+			return ret;
+
+		info.log_type = pfrt_log_dev->info.log_type;
+		info.log_revid = pfrt_log_dev->info.log_revid;
+		if (copy_to_user(p, &info, sizeof(info)))
+			return -EFAULT;
+
+		return 0;
+
+	case PFRT_LOG_IOC_GET_DATA_INFO:
+		ret = get_pfrt_log_data_info(&data_info, pfrt_log_dev);
+		if (ret)
+			return ret;
+
+		if (copy_to_user(p, &data_info, sizeof(struct pfrt_log_data_info)))
+			return -EFAULT;
+
+		return 0;
+
+	default:
+		return -ENOTTY;
+	}
+}
+
+static int
+pfrt_log_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	struct pfrt_log_device *pfrt_log_dev;
+	struct pfrt_log_data_info info;
+	unsigned long psize, vsize;
+	phys_addr_t base_addr;
+	int ret;
+
+	if (vma->vm_flags & VM_WRITE)
+		return -EROFS;
+
+	/* changing from read to write with mprotect is not allowed */
+	vma->vm_flags &= ~VM_MAYWRITE;
+
+	pfrt_log_dev = to_pfrt_log_dev(file);
+
+	ret = get_pfrt_log_data_info(&info, pfrt_log_dev);
+	if (ret)
+		return ret;
+
+	base_addr = (phys_addr_t)((info.chunk2_addr_hi << 32) | info.chunk2_addr_lo);
+	/* pfrt update has not been launched yet */
+	if (!base_addr)
+		return -ENODEV;
+
+	psize = info.max_data_size;
+	/* base address and total buffer size must be page aligned */
+	if (!PAGE_ALIGNED(base_addr) || !PAGE_ALIGNED(psize))
+		return -ENODEV;
+
+	vsize = vma->vm_end - vma->vm_start;
+	if (vsize > psize)
+		return -EINVAL;
+
+	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+	if (io_remap_pfn_range(vma, vma->vm_start, PFN_DOWN(base_addr),
+			       vsize, vma->vm_page_prot))
+		return -EAGAIN;
+
+	return 0;
+}
+
+static const struct file_operations acpi_pfrt_log_fops = {
+	.owner		= THIS_MODULE,
+	.mmap		= pfrt_log_mmap,
+	.unlocked_ioctl = pfrt_log_ioctl,
+	.llseek		= noop_llseek,
+};
+
+static int acpi_pfrt_log_remove(struct platform_device *pdev)
+{
+	struct pfrt_log_device *pfrt_log_dev = platform_get_drvdata(pdev);
+
+	misc_deregister(&pfrt_log_dev->miscdev);
+
+	return 0;
+}
+
+static void pfrt_log_put_idx(void *data)
+{
+	struct pfrt_log_device *pfrt_log_dev = data;
+
+	ida_free(&pfrt_log_ida, pfrt_log_dev->index);
+}
+
+static int acpi_pfrt_log_probe(struct platform_device *pdev)
+{
+	acpi_handle handle = ACPI_HANDLE(&pdev->dev);
+	struct pfrt_log_device *pfrt_log_dev;
+	int ret;
+
+	if (!acpi_has_method(handle, "_DSM")) {
+		dev_dbg(&pdev->dev, "Missing _DSM\n");
+		return -ENODEV;
+	}
+
+	pfrt_log_dev = devm_kzalloc(&pdev->dev, sizeof(*pfrt_log_dev), GFP_KERNEL);
+	if (!pfrt_log_dev)
+		return -ENOMEM;
+
+	ret = ida_alloc(&pfrt_log_ida, GFP_KERNEL);
+	if (ret < 0)
+		return ret;
+
+	pfrt_log_dev->index = ret;
+	ret = devm_add_action_or_reset(&pdev->dev, pfrt_log_put_idx, pfrt_log_dev);
+	if (ret)
+		return ret;
+
+	pfrt_log_dev->info.log_revid = PFRT_DEFAULT_REV_ID;
+	pfrt_log_dev->parent_dev = &pdev->dev;
+
+	pfrt_log_dev->miscdev.minor = MISC_DYNAMIC_MINOR;
+	pfrt_log_dev->miscdev.name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
+						    "pfrt%d",
+						    pfrt_log_dev->index);
+	if (!pfrt_log_dev->miscdev.name)
+		return -ENOMEM;
+
+	pfrt_log_dev->miscdev.nodename = devm_kasprintf(&pdev->dev, GFP_KERNEL,
+							"acpi_pfr_telemetry%d",
+							pfrt_log_dev->index);
+	if (!pfrt_log_dev->miscdev.nodename)
+		return -ENOMEM;
+
+	pfrt_log_dev->miscdev.fops = &acpi_pfrt_log_fops;
+	pfrt_log_dev->miscdev.parent = &pdev->dev;
+
+	ret = misc_register(&pfrt_log_dev->miscdev);
+	if (ret)
+		return ret;
+
+	platform_set_drvdata(pdev, pfrt_log_dev);
+
+	return 0;
+}
+
+static const struct acpi_device_id acpi_pfrt_log_ids[] = {
+	{"INTC1081"},
+	{}
+};
+MODULE_DEVICE_TABLE(acpi, acpi_pfrt_log_ids);
+
+static struct platform_driver acpi_pfrt_log_driver = {
+	.driver = {
+		.name = "pfr_telemetry",
+		.acpi_match_table = acpi_pfrt_log_ids,
+	},
+	.probe = acpi_pfrt_log_probe,
+	.remove = acpi_pfrt_log_remove,
+};
+module_platform_driver(acpi_pfrt_log_driver);
+
+MODULE_DESCRIPTION("Platform Firmware Runtime Update Telemetry driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/acpi/pfr_update.c b/drivers/acpi/pfr_update.c
new file mode 100644
index 000000000000..6bb0b778b5da
--- /dev/null
+++ b/drivers/acpi/pfr_update.c
@@ -0,0 +1,575 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ACPI Platform Firmware Runtime Update Device driver
+ *
+ * Copyright (C) 2021 Intel Corporation
+ * Author: Chen Yu <yu.c.chen@intel.com>
+ *
+ * pfr_update driver is used for Platform Firmware Runtime
+ * Update, which includes the code injection and driver update.
+ */
+#include <linux/acpi.h>
+#include <linux/device.h>
+#include <linux/efi.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/idr.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/string.h>
+#include <linux/uaccess.h>
+#include <linux/uio.h>
+#include <linux/uuid.h>
+
+#include <uapi/linux/pfrut.h>
+
+#define PFRU_FUNC_STANDARD_QUERY	0
+#define PFRU_FUNC_QUERY_UPDATE_CAP	1
+#define PFRU_FUNC_QUERY_BUF		2
+#define PFRU_FUNC_START		3
+
+#define PFRU_CODE_INJECT_TYPE	1
+#define PFRU_DRIVER_UPDATE_TYPE	2
+
+#define PFRU_REVID_1		1
+#define PFRU_REVID_2		2
+#define PFRU_DEFAULT_REV_ID	PFRU_REVID_1
+
+enum cap_index {
+	CAP_STATUS_IDX = 0,
+	CAP_UPDATE_IDX = 1,
+	CAP_CODE_TYPE_IDX = 2,
+	CAP_FW_VER_IDX = 3,
+	CAP_CODE_RT_VER_IDX = 4,
+	CAP_DRV_TYPE_IDX = 5,
+	CAP_DRV_RT_VER_IDX = 6,
+	CAP_DRV_SVN_IDX = 7,
+	CAP_PLAT_ID_IDX = 8,
+	CAP_OEM_ID_IDX = 9,
+	CAP_OEM_INFO_IDX = 10,
+	CAP_NR_IDX
+};
+
+enum buf_index {
+	BUF_STATUS_IDX = 0,
+	BUF_EXT_STATUS_IDX = 1,
+	BUF_ADDR_LOW_IDX = 2,
+	BUF_ADDR_HI_IDX = 3,
+	BUF_SIZE_IDX = 4,
+	BUF_NR_IDX
+};
+
+enum update_index {
+	UPDATE_STATUS_IDX = 0,
+	UPDATE_EXT_STATUS_IDX = 1,
+	UPDATE_AUTH_TIME_LOW_IDX = 2,
+	UPDATE_AUTH_TIME_HI_IDX = 3,
+	UPDATE_EXEC_TIME_LOW_IDX = 4,
+	UPDATE_EXEC_TIME_HI_IDX = 5,
+	UPDATE_NR_IDX
+};
+
+enum pfru_start_action {
+	START_STAGE = 0,
+	START_ACTIVATE = 1,
+	START_STAGE_ACTIVATE = 2,
+};
+
+struct pfru_device {
+	u32 rev_id, index;
+	struct device *parent_dev;
+	struct miscdevice miscdev;
+};
+
+static DEFINE_IDA(pfru_ida);
+
+/*
+ * Manual reference:
+ * https://uefi.org/sites/default/files/resources/Intel_MM_OS_Interface_Spec_Rev100.pdf
+ *
+ * pfru_guid is the parameter for _DSM method
+ */
+static const guid_t pfru_guid =
+	GUID_INIT(0xECF9533B, 0x4A3C, 0x4E89, 0x93, 0x9E, 0xC7, 0x71,
+		  0x12, 0x60, 0x1C, 0x6D);
+
+/* pfru_code_inj_guid is the UUID to identify code injection EFI capsule file */
+static const guid_t pfru_code_inj_guid =
+	GUID_INIT(0xB2F84B79, 0x7B6E, 0x4E45, 0x88, 0x5F, 0x3F, 0xB9,
+		  0xBB, 0x18, 0x54, 0x02);
+
+/* pfru_drv_update_guid is the UUID to identify driver update EFI capsule file */
+static const guid_t pfru_drv_update_guid =
+	GUID_INIT(0x4569DD8C, 0x75F1, 0x429A, 0xA3, 0xD6, 0x24, 0xDE,
+		  0x80, 0x97, 0xA0, 0xDF);
+
+static inline int pfru_valid_revid(u32 id)
+{
+	return id == PFRU_REVID_1 || id == PFRU_REVID_2;
+}
+
+static inline struct pfru_device *to_pfru_dev(struct file *file)
+{
+	return container_of(file->private_data, struct pfru_device, miscdev);
+}
+
+static int query_capability(struct pfru_update_cap_info *cap_hdr,
+			    struct pfru_device *pfru_dev)
+{
+	acpi_handle handle = ACPI_HANDLE(pfru_dev->parent_dev);
+	union acpi_object *out_obj;
+	int ret = -EINVAL;
+
+	out_obj = acpi_evaluate_dsm_typed(handle, &pfru_guid,
+					  pfru_dev->rev_id,
+					  PFRU_FUNC_QUERY_UPDATE_CAP,
+					  NULL, ACPI_TYPE_PACKAGE);
+	if (!out_obj)
+		return ret;
+
+	if (out_obj->package.count < CAP_NR_IDX ||
+	    out_obj->package.elements[CAP_STATUS_IDX].type != ACPI_TYPE_INTEGER ||
+	    out_obj->package.elements[CAP_UPDATE_IDX].type != ACPI_TYPE_INTEGER ||
+	    out_obj->package.elements[CAP_CODE_TYPE_IDX].type != ACPI_TYPE_BUFFER ||
+	    out_obj->package.elements[CAP_FW_VER_IDX].type != ACPI_TYPE_INTEGER ||
+	    out_obj->package.elements[CAP_CODE_RT_VER_IDX].type != ACPI_TYPE_INTEGER ||
+	    out_obj->package.elements[CAP_DRV_TYPE_IDX].type != ACPI_TYPE_BUFFER ||
+	    out_obj->package.elements[CAP_DRV_RT_VER_IDX].type != ACPI_TYPE_INTEGER ||
+	    out_obj->package.elements[CAP_DRV_SVN_IDX].type != ACPI_TYPE_INTEGER ||
+	    out_obj->package.elements[CAP_PLAT_ID_IDX].type != ACPI_TYPE_BUFFER ||
+	    out_obj->package.elements[CAP_OEM_ID_IDX].type != ACPI_TYPE_BUFFER ||
+	    out_obj->package.elements[CAP_OEM_INFO_IDX].type != ACPI_TYPE_BUFFER)
+		goto free_acpi_buffer;
+
+	cap_hdr->status = out_obj->package.elements[CAP_STATUS_IDX].integer.value;
+	if (cap_hdr->status != DSM_SUCCEED) {
+		ret = -EBUSY;
+		dev_dbg(pfru_dev->parent_dev, "Error Status:%d\n", cap_hdr->status);
+		goto free_acpi_buffer;
+	}
+
+	cap_hdr->update_cap = out_obj->package.elements[CAP_UPDATE_IDX].integer.value;
+	memcpy(&cap_hdr->code_type,
+	       out_obj->package.elements[CAP_CODE_TYPE_IDX].buffer.pointer,
+	       out_obj->package.elements[CAP_CODE_TYPE_IDX].buffer.length);
+	cap_hdr->fw_version =
+		out_obj->package.elements[CAP_FW_VER_IDX].integer.value;
+	cap_hdr->code_rt_version =
+		out_obj->package.elements[CAP_CODE_RT_VER_IDX].integer.value;
+	memcpy(&cap_hdr->drv_type,
+	       out_obj->package.elements[CAP_DRV_TYPE_IDX].buffer.pointer,
+	       out_obj->package.elements[CAP_DRV_TYPE_IDX].buffer.length);
+	cap_hdr->drv_rt_version =
+		out_obj->package.elements[CAP_DRV_RT_VER_IDX].integer.value;
+	cap_hdr->drv_svn =
+		out_obj->package.elements[CAP_DRV_SVN_IDX].integer.value;
+	memcpy(&cap_hdr->platform_id,
+	       out_obj->package.elements[CAP_PLAT_ID_IDX].buffer.pointer,
+	       out_obj->package.elements[CAP_PLAT_ID_IDX].buffer.length);
+	memcpy(&cap_hdr->oem_id,
+	       out_obj->package.elements[CAP_OEM_ID_IDX].buffer.pointer,
+	       out_obj->package.elements[CAP_OEM_ID_IDX].buffer.length);
+	cap_hdr->oem_info_len =
+		out_obj->package.elements[CAP_OEM_INFO_IDX].buffer.length;
+
+	ret = 0;
+
+free_acpi_buffer:
+	kfree(out_obj);
+
+	return ret;
+}
+
+static int query_buffer(struct pfru_com_buf_info *info,
+			struct pfru_device *pfru_dev)
+{
+	acpi_handle handle = ACPI_HANDLE(pfru_dev->parent_dev);
+	union acpi_object *out_obj;
+	int ret = -EINVAL;
+
+	out_obj = acpi_evaluate_dsm_typed(handle, &pfru_guid,
+					  pfru_dev->rev_id, PFRU_FUNC_QUERY_BUF,
+					  NULL, ACPI_TYPE_PACKAGE);
+	if (!out_obj)
+		return ret;
+
+	if (out_obj->package.count < BUF_NR_IDX ||
+	    out_obj->package.elements[BUF_STATUS_IDX].type != ACPI_TYPE_INTEGER ||
+	    out_obj->package.elements[BUF_EXT_STATUS_IDX].type != ACPI_TYPE_INTEGER ||
+	    out_obj->package.elements[BUF_ADDR_LOW_IDX].type != ACPI_TYPE_INTEGER ||
+	    out_obj->package.elements[BUF_ADDR_HI_IDX].type != ACPI_TYPE_INTEGER ||
+	    out_obj->package.elements[BUF_SIZE_IDX].type != ACPI_TYPE_INTEGER)
+		goto free_acpi_buffer;
+
+	info->status = out_obj->package.elements[BUF_STATUS_IDX].integer.value;
+	info->ext_status =
+		out_obj->package.elements[BUF_EXT_STATUS_IDX].integer.value;
+	if (info->status != DSM_SUCCEED) {
+		ret = -EBUSY;
+		dev_dbg(pfru_dev->parent_dev, "Error Status:%d\n", info->status);
+		dev_dbg(pfru_dev->parent_dev, "Error Extended Status:%d\n", info->ext_status);
+
+		goto free_acpi_buffer;
+	}
+
+	info->addr_lo =
+		out_obj->package.elements[BUF_ADDR_LOW_IDX].integer.value;
+	info->addr_hi =
+		out_obj->package.elements[BUF_ADDR_HI_IDX].integer.value;
+	info->buf_size = out_obj->package.elements[BUF_SIZE_IDX].integer.value;
+
+	ret = 0;
+
+free_acpi_buffer:
+	kfree(out_obj);
+
+	return ret;
+}
+
+static int get_image_type(const struct efi_manage_capsule_image_header *img_hdr,
+			  struct pfru_device *pfru_dev)
+{
+	const efi_guid_t *image_type_id = &img_hdr->image_type_id;
+
+	/* check whether this is a code injection or driver update */
+	if (guid_equal(image_type_id, &pfru_code_inj_guid))
+		return PFRU_CODE_INJECT_TYPE;
+
+	if (guid_equal(image_type_id, &pfru_drv_update_guid))
+		return PFRU_DRIVER_UPDATE_TYPE;
+
+	return -EINVAL;
+}
+
+static int adjust_efi_size(const struct efi_manage_capsule_image_header *img_hdr,
+			   int size)
+{
+	/*
+	 * The (u64 hw_ins) was introduced in UEFI spec version 2,
+	 * and (u64 capsule_support) was introduced in version 3.
+	 * The size needs to be adjusted accordingly. That is to
+	 * say, version 1 should subtract the size of hw_ins+capsule_support,
+	 * and version 2 should sbstract the size of capsule_support.
+	 */
+	size += sizeof(struct efi_manage_capsule_image_header);
+	switch (img_hdr->ver) {
+	case 1:
+		return size - 2 * sizeof(u64);
+
+	case 2:
+		return size - sizeof(u64);
+
+	default:
+		/* only support version 1 and 2 */
+		return -EINVAL;
+	}
+}
+
+static bool applicable_image(const void *data, struct pfru_update_cap_info *cap,
+			     struct pfru_device *pfru_dev)
+{
+	struct pfru_payload_hdr *payload_hdr;
+	const efi_capsule_header_t *cap_hdr = data;
+	const struct efi_manage_capsule_header *m_hdr;
+	const struct efi_manage_capsule_image_header *m_img_hdr;
+	const struct efi_image_auth *auth;
+	int type, size;
+
+	/*
+	 * If the code in the capsule is older than the current
+	 * firmware code, the update will be rejected by the firmware,
+	 * so check the version of it upfront without engaging the
+	 * Management Mode update mechanism which may be costly.
+	 */
+	size = cap_hdr->headersize;
+	m_hdr = data + size;
+	/*
+	 * Current data structure size plus variable array indicated
+	 * by number of (emb_drv_cnt + payload_cnt)
+	 */
+	size += offsetof(struct efi_manage_capsule_header, offset_list) +
+		(m_hdr->emb_drv_cnt + m_hdr->payload_cnt) * sizeof(u64);
+	m_img_hdr = data + size;
+
+	type = get_image_type(m_img_hdr, pfru_dev);
+	if (type < 0)
+		return false;
+
+	size = adjust_efi_size(m_img_hdr, size);
+	if (size < 0)
+		return false;
+
+	auth = data + size;
+	size += sizeof(u64) + auth->auth_info.hdr.len;
+	payload_hdr = (struct pfru_payload_hdr *)(data + size);
+
+	/* finally compare the version */
+	if (type == PFRU_CODE_INJECT_TYPE)
+		return payload_hdr->rt_ver >= cap->code_rt_version;
+
+	return payload_hdr->rt_ver >= cap->drv_rt_version;
+}
+
+static void print_update_debug_info(struct pfru_updated_result *result,
+				    struct pfru_device *pfru_dev)
+{
+	dev_dbg(pfru_dev->parent_dev, "Update result:\n");
+	dev_dbg(pfru_dev->parent_dev, "Authentication Time Low:%lld\n",
+		result->low_auth_time);
+	dev_dbg(pfru_dev->parent_dev, "Authentication Time High:%lld\n",
+		result->high_auth_time);
+	dev_dbg(pfru_dev->parent_dev, "Execution Time Low:%lld\n",
+		result->low_exec_time);
+	dev_dbg(pfru_dev->parent_dev, "Execution Time High:%lld\n",
+		result->high_exec_time);
+}
+
+static int start_update(int action, struct pfru_device *pfru_dev)
+{
+	union acpi_object *out_obj, in_obj, in_buf;
+	struct pfru_updated_result update_result;
+	acpi_handle handle;
+	int ret = -EINVAL;
+
+	memset(&in_obj, 0, sizeof(in_obj));
+	memset(&in_buf, 0, sizeof(in_buf));
+	in_obj.type = ACPI_TYPE_PACKAGE;
+	in_obj.package.count = 1;
+	in_obj.package.elements = &in_buf;
+	in_buf.type = ACPI_TYPE_INTEGER;
+	in_buf.integer.value = action;
+
+	handle = ACPI_HANDLE(pfru_dev->parent_dev);
+	out_obj = acpi_evaluate_dsm_typed(handle, &pfru_guid,
+					  pfru_dev->rev_id, PFRU_FUNC_START,
+					  &in_obj, ACPI_TYPE_PACKAGE);
+	if (!out_obj)
+		return ret;
+
+	if (out_obj->package.count < UPDATE_NR_IDX ||
+	    out_obj->package.elements[UPDATE_STATUS_IDX].type != ACPI_TYPE_INTEGER ||
+	    out_obj->package.elements[UPDATE_EXT_STATUS_IDX].type != ACPI_TYPE_INTEGER ||
+	    out_obj->package.elements[UPDATE_AUTH_TIME_LOW_IDX].type != ACPI_TYPE_INTEGER ||
+	    out_obj->package.elements[UPDATE_AUTH_TIME_HI_IDX].type != ACPI_TYPE_INTEGER ||
+	    out_obj->package.elements[UPDATE_EXEC_TIME_LOW_IDX].type != ACPI_TYPE_INTEGER ||
+	    out_obj->package.elements[UPDATE_EXEC_TIME_HI_IDX].type != ACPI_TYPE_INTEGER)
+		goto free_acpi_buffer;
+
+	update_result.status =
+		out_obj->package.elements[UPDATE_STATUS_IDX].integer.value;
+	update_result.ext_status =
+		out_obj->package.elements[UPDATE_EXT_STATUS_IDX].integer.value;
+
+	if (update_result.status != DSM_SUCCEED) {
+		ret = -EBUSY;
+		dev_dbg(pfru_dev->parent_dev, "Error Status:%d\n", update_result.status);
+		dev_dbg(pfru_dev->parent_dev, "Error Extended Status:%d\n",
+			update_result.ext_status);
+
+		goto free_acpi_buffer;
+	}
+
+	update_result.low_auth_time =
+		out_obj->package.elements[UPDATE_AUTH_TIME_LOW_IDX].integer.value;
+	update_result.high_auth_time =
+		out_obj->package.elements[UPDATE_AUTH_TIME_HI_IDX].integer.value;
+	update_result.low_exec_time =
+		out_obj->package.elements[UPDATE_EXEC_TIME_LOW_IDX].integer.value;
+	update_result.high_exec_time =
+		out_obj->package.elements[UPDATE_EXEC_TIME_HI_IDX].integer.value;
+
+	print_update_debug_info(&update_result, pfru_dev);
+	ret = 0;
+
+free_acpi_buffer:
+	kfree(out_obj);
+
+	return ret;
+}
+
+static long pfru_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct pfru_update_cap_info cap_hdr;
+	struct pfru_device *pfru_dev = to_pfru_dev(file);
+	void __user *p = (void __user *)arg;
+	u32 rev;
+	int ret;
+
+	switch (cmd) {
+	case PFRU_IOC_QUERY_CAP:
+		ret = query_capability(&cap_hdr, pfru_dev);
+		if (ret)
+			return ret;
+
+		if (copy_to_user(p, &cap_hdr, sizeof(cap_hdr)))
+			return -EFAULT;
+
+		return 0;
+
+	case PFRU_IOC_SET_REV:
+		if (copy_from_user(&rev, p, sizeof(rev)))
+			return -EFAULT;
+
+		if (!pfru_valid_revid(rev))
+			return -EINVAL;
+
+		pfru_dev->rev_id = rev;
+
+		return 0;
+
+	case PFRU_IOC_STAGE:
+		return start_update(START_STAGE, pfru_dev);
+
+	case PFRU_IOC_ACTIVATE:
+		return start_update(START_ACTIVATE, pfru_dev);
+
+	case PFRU_IOC_STAGE_ACTIVATE:
+		return start_update(START_STAGE_ACTIVATE, pfru_dev);
+
+	default:
+		return -ENOTTY;
+	}
+}
+
+static ssize_t pfru_write(struct file *file, const char __user *buf,
+			  size_t len, loff_t *ppos)
+{
+	struct pfru_device *pfru_dev = to_pfru_dev(file);
+	struct pfru_update_cap_info cap;
+	struct pfru_com_buf_info buf_info;
+	phys_addr_t phy_addr;
+	struct iov_iter iter;
+	struct iovec iov;
+	char *buf_ptr;
+	int ret;
+
+	ret = query_buffer(&buf_info, pfru_dev);
+	if (ret)
+		return ret;
+
+	if (len > buf_info.buf_size)
+		return -EINVAL;
+
+	iov.iov_base = (void __user *)buf;
+	iov.iov_len = len;
+	iov_iter_init(&iter, WRITE, &iov, 1, len);
+
+	/* map the communication buffer */
+	phy_addr = (phys_addr_t)((buf_info.addr_hi << 32) | buf_info.addr_lo);
+	buf_ptr = memremap(phy_addr, buf_info.buf_size, MEMREMAP_WB);
+	if (!buf_ptr)
+		return -ENOMEM;
+
+	if (!copy_from_iter_full(buf_ptr, len, &iter)) {
+		ret = -EINVAL;
+		goto unmap;
+	}
+
+	/* check if the capsule header has a valid version number */
+	ret = query_capability(&cap, pfru_dev);
+	if (ret)
+		goto unmap;
+
+	if (!applicable_image(buf_ptr, &cap, pfru_dev))
+		ret = -EINVAL;
+
+unmap:
+	memunmap(buf_ptr);
+
+	return ret ?: len;
+}
+
+static const struct file_operations acpi_pfru_fops = {
+	.owner		= THIS_MODULE,
+	.write		= pfru_write,
+	.unlocked_ioctl = pfru_ioctl,
+	.llseek		= noop_llseek,
+};
+
+static int acpi_pfru_remove(struct platform_device *pdev)
+{
+	struct pfru_device *pfru_dev = platform_get_drvdata(pdev);
+
+	misc_deregister(&pfru_dev->miscdev);
+
+	return 0;
+}
+
+static void pfru_put_idx(void *data)
+{
+	struct pfru_device *pfru_dev = data;
+
+	ida_free(&pfru_ida, pfru_dev->index);
+}
+
+static int acpi_pfru_probe(struct platform_device *pdev)
+{
+	acpi_handle handle = ACPI_HANDLE(&pdev->dev);
+	struct pfru_device *pfru_dev;
+	int ret;
+
+	if (!acpi_has_method(handle, "_DSM")) {
+		dev_dbg(&pdev->dev, "Missing _DSM\n");
+		return -ENODEV;
+	}
+
+	pfru_dev = devm_kzalloc(&pdev->dev, sizeof(*pfru_dev), GFP_KERNEL);
+	if (!pfru_dev)
+		return -ENOMEM;
+
+	ret = ida_alloc(&pfru_ida, GFP_KERNEL);
+	if (ret < 0)
+		return ret;
+
+	pfru_dev->index = ret;
+	ret = devm_add_action_or_reset(&pdev->dev, pfru_put_idx, pfru_dev);
+	if (ret)
+		return ret;
+
+	pfru_dev->rev_id = PFRU_DEFAULT_REV_ID;
+	pfru_dev->parent_dev = &pdev->dev;
+
+	pfru_dev->miscdev.minor = MISC_DYNAMIC_MINOR;
+	pfru_dev->miscdev.name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
+						"pfru%d", pfru_dev->index);
+	if (!pfru_dev->miscdev.name)
+		return -ENOMEM;
+
+	pfru_dev->miscdev.nodename = devm_kasprintf(&pdev->dev, GFP_KERNEL,
+						    "acpi_pfr_update%d", pfru_dev->index);
+	if (!pfru_dev->miscdev.nodename)
+		return -ENOMEM;
+
+	pfru_dev->miscdev.fops = &acpi_pfru_fops;
+	pfru_dev->miscdev.parent = &pdev->dev;
+
+	ret = misc_register(&pfru_dev->miscdev);
+	if (ret)
+		return ret;
+
+	platform_set_drvdata(pdev, pfru_dev);
+
+	return 0;
+}
+
+static const struct acpi_device_id acpi_pfru_ids[] = {
+	{"INTC1080"},
+	{}
+};
+MODULE_DEVICE_TABLE(acpi, acpi_pfru_ids);
+
+static struct platform_driver acpi_pfru_driver = {
+	.driver = {
+		.name = "pfr_update",
+		.acpi_match_table = acpi_pfru_ids,
+	},
+	.probe = acpi_pfru_probe,
+	.remove = acpi_pfru_remove,
+};
+module_platform_driver(acpi_pfru_driver);
+
+MODULE_DESCRIPTION("Platform Firmware Runtime Update device driver");
+MODULE_LICENSE("GPL v2");