soc: qcom: Add Sleep stats driver

Let's add a driver to read the stats from remote processor and
export to debugfs.

The driver creates "qcom_sleep_stats" directory in debugfs and
adds files for various low power mode available. Below is sample
output with command

cat /sys/kernel/debug/qcom_sleep_stats/ddr
count = 0
Last Entered At = 0
Last Exited At = 0
Accumulated Duration = 0

Signed-off-by: Mahesh Sivasubramanian <msivasub@codeaurora.org>
Signed-off-by: Lina Iyer <ilina@codeaurora.org>
[mkshah: add subsystem sleep stats, create one file for each stat]
Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/1634107104-22197-3-git-send-email-mkshah@codeaurora.org

drivers/soc/qcom/Kconfig

@@ -199,6 +199,16 @@ config QCOM_SPM
 	  to manage cores, L2 low power modes and to configure the internal
 	  Adaptive Voltage Scaler parameters, where supported.
 
+config QCOM_STATS
+	tristate "Qualcomm Technologies, Inc. (QTI) Sleep stats driver"
+	depends on (ARCH_QCOM && DEBUG_FS) || COMPILE_TEST
+	depends on QCOM_SMEM
+	help
+	  Qualcomm Technologies, Inc. (QTI) Sleep stats driver to read
+	  the shared memory exported by the remote processor related to
+	  various SoC level low power modes statistics and export to debugfs
+	  interface.
+
 config QCOM_WCNSS_CTRL
 	tristate "Qualcomm WCNSS control driver"
 	depends on ARCH_QCOM || COMPILE_TEST

drivers/soc/qcom/Makefile

@@ -21,6 +21,7 @@ obj-$(CONFIG_QCOM_SMP2P)	+= smp2p.o
 obj-$(CONFIG_QCOM_SMSM)	+= smsm.o
 obj-$(CONFIG_QCOM_SOCINFO)	+= socinfo.o
 obj-$(CONFIG_QCOM_SPM)		+= spm.o
+obj-$(CONFIG_QCOM_STATS)	+= qcom_stats.o
 obj-$(CONFIG_QCOM_WCNSS_CTRL) += wcnss_ctrl.o
 obj-$(CONFIG_QCOM_APR) += apr.o
 obj-$(CONFIG_QCOM_LLCC) += llcc-qcom.o

drivers/soc/qcom/qcom_stats.c

@@ -0,0 +1,277 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2011-2021, The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/debugfs.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/seq_file.h>
+
+#include <linux/soc/qcom/smem.h>
+#include <clocksource/arm_arch_timer.h>
+
+#define RPM_DYNAMIC_ADDR	0x14
+#define RPM_DYNAMIC_ADDR_MASK	0xFFFF
+
+#define STAT_TYPE_OFFSET	0x0
+#define COUNT_OFFSET		0x4
+#define LAST_ENTERED_AT_OFFSET	0x8
+#define LAST_EXITED_AT_OFFSET	0x10
+#define ACCUMULATED_OFFSET	0x18
+#define CLIENT_VOTES_OFFSET	0x1c
+
+struct subsystem_data {
+	const char *name;
+	u32 smem_item;
+	u32 pid;
+};
+
+static const struct subsystem_data subsystems[] = {
+	{ "modem", 605, 1 },
+	{ "wpss", 605, 13 },
+	{ "adsp", 606, 2 },
+	{ "cdsp", 607, 5 },
+	{ "slpi", 608, 3 },
+	{ "gpu", 609, 0 },
+	{ "display", 610, 0 },
+	{ "adsp_island", 613, 2 },
+	{ "slpi_island", 613, 3 },
+};
+
+struct stats_config {
+	size_t stats_offset;
+	size_t num_records;
+	bool appended_stats_avail;
+	bool dynamic_offset;
+	bool subsystem_stats_in_smem;
+};
+
+struct stats_data {
+	bool appended_stats_avail;
+	void __iomem *base;
+};
+
+struct sleep_stats {
+	u32 stat_type;
+	u32 count;
+	u64 last_entered_at;
+	u64 last_exited_at;
+	u64 accumulated;
+};
+
+struct appended_stats {
+	u32 client_votes;
+	u32 reserved[3];
+};
+
+static void qcom_print_stats(struct seq_file *s, const struct sleep_stats *stat)
+{
+	u64 accumulated = stat->accumulated;
+	/*
+	 * If a subsystem is in sleep when reading the sleep stats adjust
+	 * the accumulated sleep duration to show actual sleep time.
+	 */
+	if (stat->last_entered_at > stat->last_exited_at)
+		accumulated += arch_timer_read_counter() - stat->last_entered_at;
+
+	seq_printf(s, "Count: %u\n", stat->count);
+	seq_printf(s, "Last Entered At: %llu\n", stat->last_entered_at);
+	seq_printf(s, "Last Exited At: %llu\n", stat->last_exited_at);
+	seq_printf(s, "Accumulated Duration: %llu\n", accumulated);
+}
+
+static int qcom_subsystem_sleep_stats_show(struct seq_file *s, void *unused)
+{
+	struct subsystem_data *subsystem = s->private;
+	struct sleep_stats *stat;
+
+	/* Items are allocated lazily, so lookup pointer each time */
+	stat = qcom_smem_get(subsystem->pid, subsystem->smem_item, NULL);
+	if (IS_ERR(stat))
+		return -EIO;
+
+	qcom_print_stats(s, stat);
+
+	return 0;
+}
+
+static int qcom_soc_sleep_stats_show(struct seq_file *s, void *unused)
+{
+	struct stats_data *d = s->private;
+	void __iomem *reg = d->base;
+	struct sleep_stats stat;
+
+	memcpy_fromio(&stat, reg, sizeof(stat));
+	qcom_print_stats(s, &stat);
+
+	if (d->appended_stats_avail) {
+		struct appended_stats votes;
+
+		memcpy_fromio(&votes, reg + CLIENT_VOTES_OFFSET, sizeof(votes));
+		seq_printf(s, "Client Votes: %#x\n", votes.client_votes);
+	}
+
+	return 0;
+}
+
+DEFINE_SHOW_ATTRIBUTE(qcom_soc_sleep_stats);
+DEFINE_SHOW_ATTRIBUTE(qcom_subsystem_sleep_stats);
+
+static void qcom_create_soc_sleep_stat_files(struct dentry *root, void __iomem *reg,
+					     struct stats_data *d,
+					     const struct stats_config *config)
+{
+	char stat_type[sizeof(u32) + 1] = {0};
+	size_t stats_offset = config->stats_offset;
+	u32 offset = 0, type;
+	int i, j;
+
+	/*
+	 * On RPM targets, stats offset location is dynamic and changes from target
+	 * to target and sometimes from build to build for same target.
+	 *
+	 * In such cases the dynamic address is present at 0x14 offset from base
+	 * address in devicetree. The last 16bits indicates the stats_offset.
+	 */
+	if (config->dynamic_offset) {
+		stats_offset = readl(reg + RPM_DYNAMIC_ADDR);
+		stats_offset &= RPM_DYNAMIC_ADDR_MASK;
+	}
+
+	for (i = 0; i < config->num_records; i++) {
+		d[i].base = reg + offset + stats_offset;
+
+		/*
+		 * Read the low power mode name and create debugfs file for it.
+		 * The names read could be of below,
+		 * (may change depending on low power mode supported).
+		 * For rpmh-sleep-stats: "aosd", "cxsd" and "ddr".
+		 * For rpm-sleep-stats: "vmin" and "vlow".
+		 */
+		type = readl(d[i].base);
+		for (j = 0; j < sizeof(u32); j++) {
+			stat_type[j] = type & 0xff;
+			type = type >> 8;
+		}
+		strim(stat_type);
+		debugfs_create_file(stat_type, 0400, root, &d[i],
+				    &qcom_soc_sleep_stats_fops);
+
+		offset += sizeof(struct sleep_stats);
+		if (d[i].appended_stats_avail)
+			offset += sizeof(struct appended_stats);
+	}
+}
+
+static void qcom_create_subsystem_stat_files(struct dentry *root,
+					     const struct stats_config *config)
+{
+	const struct sleep_stats *stat;
+	int i;
+
+	if (!config->subsystem_stats_in_smem)
+		return;
+
+	for (i = 0; i < ARRAY_SIZE(subsystems); i++) {
+		stat = qcom_smem_get(subsystems[i].pid, subsystems[i].smem_item, NULL);
+		if (IS_ERR(stat))
+			continue;
+
+		debugfs_create_file(subsystems[i].name, 0400, root, (void *)&subsystems[i],
+				    &qcom_subsystem_sleep_stats_fops);
+	}
+}
+
+static int qcom_stats_probe(struct platform_device *pdev)
+{
+	void __iomem *reg;
+	struct dentry *root;
+	const struct stats_config *config;
+	struct stats_data *d;
+	int i;
+
+	config = device_get_match_data(&pdev->dev);
+	if (!config)
+		return -ENODEV;
+
+	reg = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
+	if (IS_ERR(reg))
+		return -ENOMEM;
+
+	d = devm_kcalloc(&pdev->dev, config->num_records,
+			 sizeof(*d), GFP_KERNEL);
+	if (!d)
+		return -ENOMEM;
+
+	for (i = 0; i < config->num_records; i++)
+		d[i].appended_stats_avail = config->appended_stats_avail;
+
+	root = debugfs_create_dir("qcom_stats", NULL);
+
+	qcom_create_subsystem_stat_files(root, config);
+	qcom_create_soc_sleep_stat_files(root, reg, d, config);
+
+	platform_set_drvdata(pdev, root);
+
+	return 0;
+}
+
+static int qcom_stats_remove(struct platform_device *pdev)
+{
+	struct dentry *root = platform_get_drvdata(pdev);
+
+	debugfs_remove_recursive(root);
+
+	return 0;
+}
+
+static const struct stats_config rpm_data = {
+	.stats_offset = 0,
+	.num_records = 2,
+	.appended_stats_avail = true,
+	.dynamic_offset = true,
+	.subsystem_stats_in_smem = false,
+};
+
+static const struct stats_config rpmh_data = {
+	.stats_offset = 0x48,
+	.num_records = 3,
+	.appended_stats_avail = false,
+	.dynamic_offset = false,
+	.subsystem_stats_in_smem = true,
+};
+
+static const struct of_device_id qcom_stats_table[] = {
+	{ .compatible = "qcom,rpm-stats", .data = &rpm_data },
+	{ .compatible = "qcom,rpmh-stats", .data = &rpmh_data },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, qcom_stats_table);
+
+static struct platform_driver qcom_stats = {
+	.probe = qcom_stats_probe,
+	.remove = qcom_stats_remove,
+	.driver = {
+		.name = "qcom_stats",
+		.of_match_table = qcom_stats_table,
+	},
+};
+
+static int __init qcom_stats_init(void)
+{
+	return platform_driver_register(&qcom_stats);
+}
+late_initcall(qcom_stats_init);
+
+static void __exit qcom_stats_exit(void)
+{
+	platform_driver_unregister(&qcom_stats);
+}
+module_exit(qcom_stats_exit)
+
+MODULE_DESCRIPTION("Qualcomm Technologies, Inc. (QTI) Stats driver");
+MODULE_LICENSE("GPL v2");