soc: qcom: qcom_stats: Add support to read DDR statistic

DDR statistic provide different DDR LPM and DDR frequency statistic.
Add support to read from MSGRAM and display via debugfs.

Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Maulik Shah <maulik.shah@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20250611-ddr_stats_-v5-1-24b16dd67c9c@oss.qualcomm.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

Author: maulik-k-shah

drivers/soc/qcom/qcom_stats.c

@@ -1,8 +1,10 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (c) 2011-2021, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2022-2025, Qualcomm Innovation Center, Inc. All rights reserved.
  */
 
+#include <linux/bitfield.h>
 #include <linux/debugfs.h>
 #include <linux/device.h>
 #include <linux/io.h>
@@ -24,6 +26,17 @@
 #define ACCUMULATED_OFFSET	0x18
 #define CLIENT_VOTES_OFFSET	0x20
 
+#define DDR_STATS_MAGIC_KEY		0xA1157A75
+#define DDR_STATS_MAX_NUM_MODES		20
+#define DDR_STATS_MAGIC_KEY_ADDR	0x0
+#define DDR_STATS_NUM_MODES_ADDR	0x4
+#define DDR_STATS_ENTRY_START_ADDR	0x8
+
+#define DDR_STATS_CP_IDX(data)		FIELD_GET(GENMASK(4, 0), data)
+#define DDR_STATS_LPM_NAME(data)	FIELD_GET(GENMASK(7, 0), data)
+#define DDR_STATS_TYPE(data)		FIELD_GET(GENMASK(15, 8), data)
+#define DDR_STATS_FREQ(data)		FIELD_GET(GENMASK(31, 16), data)
+
 struct subsystem_data {
 	const char *name;
 	u32 smem_item;
@@ -48,12 +61,19 @@ static const struct subsystem_data subsystems[] = {
 
 struct stats_config {
 	size_t stats_offset;
+	size_t ddr_stats_offset;
 	size_t num_records;
 	bool appended_stats_avail;
 	bool dynamic_offset;
 	bool subsystem_stats_in_smem;
 };
 
+struct ddr_stats_entry {
+	u32 name;
+	u32 count;
+	u64 duration;
+};
+
 struct stats_data {
 	bool appended_stats_avail;
 	void __iomem *base;
@@ -122,8 +142,85 @@ static int qcom_soc_sleep_stats_show(struct seq_file *s, void *unused)
 	return 0;
 }
 
+static void qcom_ddr_stats_print(struct seq_file *s, struct ddr_stats_entry *data)
+{
+	u32 cp_idx;
+
+	/*
+	 * DDR statistic have two different types of details encoded.
+	 * (1) DDR LPM Stats
+	 * (2) DDR Frequency Stats
+	 *
+	 * The name field have details like which type of DDR stat (bits 8:15)
+	 * along with other details as explained below
+	 *
+	 * In case of DDR LPM stat, name field will be encoded as,
+	 * Bits	 -  Meaning
+	 * 0:7	 -  DDR LPM name, can be of 0xd4, 0xd3, 0x11 and 0xd0.
+	 * 8:15	 -  0x0 (indicates its a LPM stat)
+	 * 16:31 -  Unused
+	 *
+	 * In case of DDR FREQ stats, name field will be encoded as,
+	 * Bits  -  Meaning
+	 * 0:4   -  DDR Clock plan index (CP IDX)
+	 * 5:7   -  Unused
+	 * 8:15  -  0x1 (indicates its Freq stat)
+	 * 16:31 -  Frequency value in Mhz
+	 */
+	switch (DDR_STATS_TYPE(data->name)) {
+	case 0:
+		seq_printf(s, "DDR LPM Stat Name:0x%lx\tcount:%u\tDuration (ticks):%llu\n",
+			   DDR_STATS_LPM_NAME(data->name), data->count, data->duration);
+		break;
+	case 1:
+		if (!data->count || !DDR_STATS_FREQ(data->name))
+			return;
+
+		cp_idx = DDR_STATS_CP_IDX(data->name);
+		seq_printf(s, "DDR Freq %luMhz:\tCP IDX:%u\tcount:%u\tDuration (ticks):%llu\n",
+			   DDR_STATS_FREQ(data->name), cp_idx, data->count, data->duration);
+		break;
+	}
+}
+
+static int qcom_ddr_stats_show(struct seq_file *s, void *d)
+{
+	struct ddr_stats_entry data[DDR_STATS_MAX_NUM_MODES];
+	void __iomem *reg = (void __iomem *)s->private;
+	u32 entry_count;
+	int i;
+
+	entry_count = readl_relaxed(reg + DDR_STATS_NUM_MODES_ADDR);
+	if (entry_count > DDR_STATS_MAX_NUM_MODES)
+		return -EINVAL;
+
+	reg += DDR_STATS_ENTRY_START_ADDR;
+	memcpy_fromio(data, reg, sizeof(struct ddr_stats_entry) * entry_count);
+
+	for (i = 0; i < entry_count; i++)
+		qcom_ddr_stats_print(s, &data[i]);
+
+	return 0;
+}
+
 DEFINE_SHOW_ATTRIBUTE(qcom_soc_sleep_stats);
 DEFINE_SHOW_ATTRIBUTE(qcom_subsystem_sleep_stats);
+DEFINE_SHOW_ATTRIBUTE(qcom_ddr_stats);
+
+static void qcom_create_ddr_stat_files(struct dentry *root, void __iomem *reg,
+				       const struct stats_config *config)
+{
+	u32 key;
+
+	if (!config->ddr_stats_offset)
+		return;
+
+	key = readl_relaxed(reg + config->ddr_stats_offset + DDR_STATS_MAGIC_KEY_ADDR);
+	if (key == DDR_STATS_MAGIC_KEY)
+		debugfs_create_file("ddr_stats", 0400, root,
+				    (__force void *)reg + config->ddr_stats_offset,
+				    &qcom_ddr_stats_fops);
+}
 
 static void qcom_create_soc_sleep_stat_files(struct dentry *root, void __iomem *reg,
 					     struct stats_data *d,
@@ -212,6 +309,7 @@ static int qcom_stats_probe(struct platform_device *pdev)
 
 	qcom_create_subsystem_stat_files(root, config);
 	qcom_create_soc_sleep_stat_files(root, reg, d, config);
+	qcom_create_ddr_stat_files(root, reg, config);
 
 	platform_set_drvdata(pdev, root);
 
@@ -254,6 +352,7 @@ static const struct stats_config rpmh_data_sdm845 = {
 
 static const struct stats_config rpmh_data = {
 	.stats_offset = 0x48,
+	.ddr_stats_offset = 0xb8,
 	.num_records = 3,
 	.appended_stats_avail = false,
 	.dynamic_offset = false,