[V3,2/3] soc: qcom: boot_stat: Add Driver Support for Boot Stats

diff --git a/Documentation/ABI/testing/debugfs-driver-bootstat b/Documentation/ABI/testing/debugfs-driver-bootstat
new file mode 100644
index 0000000..37d8e32
--- /dev/null
+++ b/Documentation/ABI/testing/debugfs-driver-bootstat
@@ -0,0 +1,17 @@ 
+What:		/sys/kernel/debug/...stats/pre_abl_time
+Date:           April 2023
+Contact:        Souradeep Chowdhury <quic_schowdhu@quicinc.com>
+Description:
+		This file is used to read the KPI value pre abl time.
+		It shows the time in milliseconds from the starting
+		point of PBL to the point when the control shifted
+		to ABL(Qualcomm proprietary bootloader).
+
+What:           /sys/kernel/debug/...stats/abl_time
+Date:           April 2023
+Contact:        Souradeep Chowdhury <quic_schowdhu@quicinc.com>
+Description:
+		This file is used to read the KPI value abl time.
+		It show the duration in milliseconds from the
+		time control switched to ABL to the point when
+		the linux kernel started getting loaded.
diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
index a8f2830..0d2cbd3 100644
--- a/drivers/soc/qcom/Kconfig
+++ b/drivers/soc/qcom/Kconfig
@@ -16,6 +16,15 @@  config QCOM_AOSS_QMP
 	  subsystems as well as controlling the debug clocks exposed by the Always On
 	  Subsystem (AOSS) using Qualcomm Messaging Protocol (QMP).

+config QCOM_BOOTSTAT
+	tristate "Qualcomm Technologies, Boot Stat driver"
+	depends on ARCH_QCOM || COMPILE_TEST
+	help
+	  This option enables driver support for boot stats. Boot stat driver logs
+	  the kernel bootloader information by accessing the imem region. These
+	  information is exposed in the form of debugfs files. This is used to
+	  determine if there is any regression in boot timings.
+
 config QCOM_COMMAND_DB
 	tristate "Qualcomm Command DB"
 	depends on ARCH_QCOM || COMPILE_TEST
diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
index 6e88da8..bdaa41a 100644
--- a/drivers/soc/qcom/Makefile
+++ b/drivers/soc/qcom/Makefile
@@ -1,6 +1,7 @@ 
 # SPDX-License-Identifier: GPL-2.0
 CFLAGS_rpmh-rsc.o := -I$(src)
 obj-$(CONFIG_QCOM_AOSS_QMP) +=	qcom_aoss.o
+obj-$(CONFIG_QCOM_BOOTSTAT) += boot_stats.o
 obj-$(CONFIG_QCOM_GENI_SE) +=	qcom-geni-se.o
 obj-$(CONFIG_QCOM_COMMAND_DB) += cmd-db.o
 obj-$(CONFIG_QCOM_CPR)		+= cpr.o
diff --git a/drivers/soc/qcom/boot_stats.c b/drivers/soc/qcom/boot_stats.c
new file mode 100644
index 0000000..9b65aa1
--- /dev/null
+++ b/drivers/soc/qcom/boot_stats.c
@@ -0,0 +1,109 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2013-2019, 2021 The Linux Foundation. All rights reserved.
+ * Copyright (c) 2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include <linux/debugfs.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+
+#define TO_MS(timestamp) ((timestamp * 1000) / 32768)
+
+/**
+ *  struct boot_stats - timestamp information related to boot stats
+ *  @abl_start: Time for the starting point of the abl
+ *  @abl_end: Time when the kernel starts loading from abl
+ */
+struct boot_stats {
+	u32 abl_start;
+	u32 abl_end;
+} __packed;
+
+static struct boot_stats __iomem *boot_stats;
+static struct dentry *dbg_dir;
+
+static ssize_t abl_read(struct file *filp, char __user *userbuf,
+			size_t count, loff_t *ppos)
+{
+	char buf[20];
+
+	u32 abl_time = TO_MS(boot_stats->abl_end) - TO_MS(boot_stats->abl_start);
+
+	sprintf(buf, "%u ms\n", abl_time);
+	return simple_read_from_buffer(userbuf, count, ppos, buf, strlen(buf));
+}
+
+static const struct file_operations abl_fops = {
+	.read = abl_read,
+	.open = simple_open,
+	.llseek = generic_file_llseek,
+};
+
+static ssize_t pre_abl_read(struct file *filp, char __user *userbuf,
+			    size_t count, loff_t *ppos)
+{
+	char buf[20];
+
+	sprintf(buf, "%u ms\n", TO_MS(boot_stats->abl_start));
+	return simple_read_from_buffer(userbuf, count, ppos, buf, strlen(buf));
+}
+
+static const struct file_operations pre_abl_fops = {
+	.read = pre_abl_read,
+	.open = simple_open,
+	.llseek = generic_file_llseek,
+};
+
+static int boot_stats_probe(struct platform_device *pdev)
+{
+	struct device *boot_stat = &pdev->dev;
+
+	dbg_dir = debugfs_create_dir(dev_name(&pdev->dev), NULL);
+	if (IS_ERR(dbg_dir))
+		return dev_err_probe(&pdev->dev, -ENOENT,
+				     "failed to create debugfs directory");
+
+	boot_stats = of_iomap(boot_stat->of_node, 0);
+	if (!boot_stats)
+		return dev_err_probe(&pdev->dev, -ENOMEM,
+				"failed to map imem region\n");
+
+	debugfs_create_file("pre_abl_time", 0200, dbg_dir, NULL, &pre_abl_fops);
+	debugfs_create_file("abl_time", 0200, dbg_dir, NULL, &abl_fops);
+
+	return 0;
+}
+
+static int boot_stats_remove(struct platform_device *pdev)
+{
+	debugfs_remove_recursive(dbg_dir);
+	iounmap(boot_stats);
+
+	return 0;
+}
+
+static const struct of_device_id boot_stats_dt_match[] = {
+	{ .compatible = "qcom,sm8450-bootstats" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, boot_stats_dt_match);
+
+static struct platform_driver boot_stat_driver = {
+	.probe  = boot_stats_probe,
+	.remove = boot_stats_remove,
+	.driver = {
+		.name = "qcom-boot-stats",
+		.of_match_table = boot_stats_dt_match,
+	},
+};
+module_platform_driver(boot_stat_driver);
+
+MODULE_DESCRIPTION("Qualcomm Technologies Inc. Boot Stat driver");
+MODULE_LICENSE("GPL");