ACPI: introduce support for FPDT table

ACPI Firmware Performance Data Table (FPDT) provides information about
firmware performance during system boot, S3 suspend and S3 resume.

Have the kernel parse the FPDT table, and expose the firmware
performance data to userspace as sysfs attributes under
/sys/firmware/acpi/fpdt/.

Tested-by: Todd Brandt <todd.e.brandt@linux.intel.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>

Documentation/ABI/testing/sysfs-firmware-acpi

@@ -1,3 +1,46 @@
+What:		/sys/firmware/acpi/fpdt/
+Date:		Jan 2021
+Contact:	Zhang Rui <rui.zhang@intel.com>
+Description:
+		ACPI Firmware Performance Data Table (FPDT) provides
+		information for firmware performance data for system boot,
+		S3 suspend and S3 resume. This sysfs entry contains the
+		performance data retrieved from the FPDT.
+
+		boot:
+			firmware_start_ns: Timer value logged at the beginning
+				of firmware image execution. In nanoseconds.
+			bootloader_load_ns: Timer value logged just prior to
+				loading the OS boot loader into memory.
+				In nanoseconds.
+			bootloader_launch_ns: Timer value logged just prior to
+				launching the currently loaded OS boot loader
+				image. In nanoseconds.
+			exitbootservice_start_ns: Timer value logged at the
+				point when the OS loader calls the
+				ExitBootServices function for UEFI compatible
+				firmware. In nanoseconds.
+			exitbootservice_end_ns: Timer value logged at the point
+				just prior to the OS loader gaining control
+				back from the ExitBootServices function for
+				UEFI compatible firmware. In nanoseconds.
+		suspend:
+			suspend_start_ns: Timer value recorded at the previous
+				OS write to SLP_TYP upon entry to S3. In
+				nanoseconds.
+			suspend_end_ns: Timer value recorded at the previous
+				firmware write to SLP_TYP used to trigger
+				hardware entry to S3. In nanoseconds.
+		resume:
+			resume_count: A count of the number of S3 resume cycles
+				since the last full boot sequence.
+			resume_avg_ns: Average timer value of all resume cycles
+				logged since the last full boot sequence,
+				including the most recent resume. In nanoseconds.
+			resume_prev_ns: Timer recorded at the end of the previous
+				platform runtime firmware S3 resume, just prior to
+				handoff to the OS waking vector. In nanoseconds.
+
 What:		/sys/firmware/acpi/bgrt/
 Date:		January 2012
 Contact:	Matthew Garrett <mjg@redhat.com>

drivers/acpi/Kconfig

@@ -87,6 +87,14 @@ config ACPI_SPCR_TABLE
 	  This table provides information about the configuration of the
 	  earlycon console.
 
+config ACPI_FPDT
+	bool "ACPI Firmware Performance Data Table(FPDT)"
+	depends on X86_64
+	help
+	  Enable support for the Firmware Performance Data Table (FPDT).
+	  This table provides information on the timing of the system
+	  boot, S3 suspend and S3 resume firmware code paths.
+
 config ACPI_LPIT
 	bool
 	depends on X86_64

drivers/acpi/Makefile

@@ -57,6 +57,7 @@ acpi-$(CONFIG_X86)		+= x86/utils.o
 acpi-$(CONFIG_X86)		+= x86/s2idle.o
 acpi-$(CONFIG_DEBUG_FS)		+= debugfs.o
 acpi-y				+= acpi_lpat.o
+acpi-$(CONFIG_ACPI_FPDT)	+= acpi_fpdt.o
 acpi-$(CONFIG_ACPI_LPIT)	+= acpi_lpit.o
 acpi-$(CONFIG_ACPI_GENERIC_GSI) += irq.o
 acpi-$(CONFIG_ACPI_WATCHDOG)	+= acpi_watchdog.o

drivers/acpi/acpi_fpdt.c

@@ -0,0 +1,263 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+/*
+ * FPDT support for exporting boot and suspend/resume performance data
+ *
+ * Copyright (C) 2021 Intel Corporation. All rights reserved.
+ */
+
+#define pr_fmt(fmt) "ACPI FPDT: " fmt
+
+#include <linux/acpi.h>
+
+/*
+ * FPDT contains ACPI table header and a number of fpdt_subtable_entries.
+ * Each fpdt_subtable_entry points to a subtable: FBPT or S3PT.
+ * Each FPDT subtable (FBPT/S3PT) is composed of a fpdt_subtable_header
+ * and a number of fpdt performance records.
+ * Each FPDT performance record is composed of a fpdt_record_header and
+ * performance data fields, for boot or suspend or resume phase.
+ */
+enum fpdt_subtable_type {
+	SUBTABLE_FBPT,
+	SUBTABLE_S3PT,
+};
+
+struct fpdt_subtable_entry {
+	u16 type;		/* refer to enum fpdt_subtable_type */
+	u8 length;
+	u8 revision;
+	u32 reserved;
+	u64 address;		/* physical address of the S3PT/FBPT table */
+};
+
+struct fpdt_subtable_header {
+	u32 signature;
+	u32 length;
+};
+
+enum fpdt_record_type {
+	RECORD_S3_RESUME,
+	RECORD_S3_SUSPEND,
+	RECORD_BOOT,
+};
+
+struct fpdt_record_header {
+	u16 type;		/* refer to enum fpdt_record_type */
+	u8 length;
+	u8 revision;
+};
+
+struct resume_performance_record {
+	struct fpdt_record_header header;
+	u32 resume_count;
+	u64 resume_prev;
+	u64 resume_avg;
+} __attribute__((packed));
+
+struct boot_performance_record {
+	struct fpdt_record_header header;
+	u32 reserved;
+	u64 firmware_start;
+	u64 bootloader_load;
+	u64 bootloader_launch;
+	u64 exitbootservice_start;
+	u64 exitbootservice_end;
+} __attribute__((packed));
+
+struct suspend_performance_record {
+	struct fpdt_record_header header;
+	u64 suspend_start;
+	u64 suspend_end;
+} __attribute__((packed));
+
+
+static struct resume_performance_record *record_resume;
+static struct suspend_performance_record *record_suspend;
+static struct boot_performance_record *record_boot;
+
+#define FPDT_ATTR(phase, name)	\
+static ssize_t name##_show(struct kobject *kobj,	\
+		 struct kobj_attribute *attr, char *buf)	\
+{	\
+	return sprintf(buf, "%llu\n", record_##phase->name);	\
+}	\
+static struct kobj_attribute name##_attr =	\
+__ATTR(name##_ns, 0444, name##_show, NULL)
+
+FPDT_ATTR(resume, resume_prev);
+FPDT_ATTR(resume, resume_avg);
+FPDT_ATTR(suspend, suspend_start);
+FPDT_ATTR(suspend, suspend_end);
+FPDT_ATTR(boot, firmware_start);
+FPDT_ATTR(boot, bootloader_load);
+FPDT_ATTR(boot, bootloader_launch);
+FPDT_ATTR(boot, exitbootservice_start);
+FPDT_ATTR(boot, exitbootservice_end);
+
+static ssize_t resume_count_show(struct kobject *kobj,
+				 struct kobj_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%u\n", record_resume->resume_count);
+}
+
+static struct kobj_attribute resume_count_attr =
+__ATTR_RO(resume_count);
+
+static struct attribute *resume_attrs[] = {
+	&resume_count_attr.attr,
+	&resume_prev_attr.attr,
+	&resume_avg_attr.attr,
+	NULL
+};
+
+static const struct attribute_group resume_attr_group = {
+	.attrs = resume_attrs,
+	.name = "resume",
+};
+
+static struct attribute *suspend_attrs[] = {
+	&suspend_start_attr.attr,
+	&suspend_end_attr.attr,
+	NULL
+};
+
+static const struct attribute_group suspend_attr_group = {
+	.attrs = suspend_attrs,
+	.name = "suspend",
+};
+
+static struct attribute *boot_attrs[] = {
+	&firmware_start_attr.attr,
+	&bootloader_load_attr.attr,
+	&bootloader_launch_attr.attr,
+	&exitbootservice_start_attr.attr,
+	&exitbootservice_end_attr.attr,
+	NULL
+};
+
+static const struct attribute_group boot_attr_group = {
+	.attrs = boot_attrs,
+	.name = "boot",
+};
+
+static struct kobject *fpdt_kobj;
+
+static int fpdt_process_subtable(u64 address, u32 subtable_type)
+{
+	struct fpdt_subtable_header *subtable_header;
+	struct fpdt_record_header *record_header;
+	char *signature = (subtable_type == SUBTABLE_FBPT ? "FBPT" : "S3PT");
+	u32 length, offset;
+	int result;
+
+	subtable_header = acpi_os_map_memory(address, sizeof(*subtable_header));
+	if (!subtable_header)
+		return -ENOMEM;
+
+	if (strncmp((char *)&subtable_header->signature, signature, 4)) {
+		pr_info(FW_BUG "subtable signature and type mismatch!\n");
+		return -EINVAL;
+	}
+
+	length = subtable_header->length;
+	acpi_os_unmap_memory(subtable_header, sizeof(*subtable_header));
+
+	subtable_header = acpi_os_map_memory(address, length);
+	if (!subtable_header)
+		return -ENOMEM;
+
+	offset = sizeof(*subtable_header);
+	while (offset < length) {
+		record_header = (void *)subtable_header + offset;
+		offset += record_header->length;
+
+		switch (record_header->type) {
+		case RECORD_S3_RESUME:
+			if (subtable_type != SUBTABLE_S3PT) {
+				pr_err(FW_BUG "Invalid record %d for subtable %s\n",
+				     record_header->type, signature);
+				return -EINVAL;
+			}
+			if (record_resume) {
+				pr_err("Duplicate resume performance record found.\n");
+				continue;
+			}
+			record_resume = (struct resume_performance_record *)record_header;
+			result = sysfs_create_group(fpdt_kobj, &resume_attr_group);
+			if (result)
+				return result;
+			break;
+		case RECORD_S3_SUSPEND:
+			if (subtable_type != SUBTABLE_S3PT) {
+				pr_err(FW_BUG "Invalid %d for subtable %s\n",
+				     record_header->type, signature);
+				continue;
+			}
+			if (record_suspend) {
+				pr_err("Duplicate suspend performance record found.\n");
+				continue;
+			}
+			record_suspend = (struct suspend_performance_record *)record_header;
+			result = sysfs_create_group(fpdt_kobj, &suspend_attr_group);
+			if (result)
+				return result;
+			break;
+		case RECORD_BOOT:
+			if (subtable_type != SUBTABLE_FBPT) {
+				pr_err(FW_BUG "Invalid %d for subtable %s\n",
+				     record_header->type, signature);
+				return -EINVAL;
+			}
+			if (record_boot) {
+				pr_err("Duplicate boot performance record found.\n");
+				continue;
+			}
+			record_boot = (struct boot_performance_record *)record_header;
+			result = sysfs_create_group(fpdt_kobj, &boot_attr_group);
+			if (result)
+				return result;
+			break;
+
+		default:
+			pr_err(FW_BUG "Invalid record %d found.\n", record_header->type);
+			return -EINVAL;
+		}
+	}
+	return 0;
+}
+
+void acpi_init_fpdt(void)
+{
+	acpi_status status;
+	struct acpi_table_header *header;
+	struct fpdt_subtable_entry *subtable;
+	u32 offset = sizeof(*header);
+
+	status = acpi_get_table(ACPI_SIG_FPDT, 0, &header);
+
+	if (ACPI_FAILURE(status))
+		return;
+
+	fpdt_kobj = kobject_create_and_add("fpdt", acpi_kobj);
+	if (!fpdt_kobj)
+		return;
+
+	while (offset < header->length) {
+		subtable = (void *)header + offset;
+		switch (subtable->type) {
+		case SUBTABLE_FBPT:
+		case SUBTABLE_S3PT:
+			fpdt_process_subtable(subtable->address,
+					      subtable->type);
+			break;
+		default:
+			pr_info(FW_BUG, "Invalid subtable type %d found.\n",
+			       subtable->type);
+			return;
+		}
+		offset += sizeof(*subtable);
+	}
+}
+
+fs_initcall(acpi_init_fpdt);