interconnect: qcom: Add debug library

Add a debug library that provides QCOM-specific interconnect debug
features. This includes support for printing all enabled interconnect
votes to console when entering suspend.

Change-Id: I61302f95c94176f833bd1c88ddc76b88121b3f79
Signed-off-by: Mike Tipton <mdtipton@codeaurora.org>

drivers/interconnect/qcom/Kconfig

@@ -178,3 +178,11 @@ config INTERCONNECT_QCOM_SMD_RPM
 
 config INTERCONNECT_QCOM_QOS
 	tristate
+
+config INTERCONNECT_QCOM_DEBUG
+	tristate "QCOM-specific interconnect debug features"
+	depends on INTERCONNECT_QCOM
+	help
+          This driver provides QCOM-specific interconnect debug features. These
+          features include optionally printing all enabled interconnect votes
+          when entering suspend.

drivers/interconnect/qcom/Makefile

@@ -43,3 +43,4 @@ obj-$(CONFIG_INTERCONNECT_QCOM_SM8350) += qnoc-sm8350.o
 obj-$(CONFIG_INTERCONNECT_QCOM_SM8450) += qnoc-sm8450.o
 obj-$(CONFIG_INTERCONNECT_QCOM_SMD_RPM) += icc-smd-rpm.o
 obj-$(CONFIG_INTERCONNECT_QCOM_QOS) += qnoc-qos.o
+obj-$(CONFIG_INTERCONNECT_QCOM_DEBUG) += icc-debug.o

drivers/interconnect/qcom/icc-debug.c

@@ -0,0 +1,175 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2021, The Linux Foundation. All rights reserved. */
+
+#include <linux/debugfs.h>
+#include <linux/device.h>
+#include <linux/interconnect-provider.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <trace/events/power.h>
+
+#include "../internal.h"
+
+static LIST_HEAD(icc_providers);
+static DEFINE_MUTEX(debug_lock);
+static struct dentry *dentry_suspend;
+static bool debug_suspend;
+
+struct qcom_icc_debug_provider {
+	struct list_head list;
+	struct icc_provider *provider;
+};
+
+static int icc_print_enabled(void)
+{
+	struct qcom_icc_debug_provider *dp;
+	struct icc_provider *provider;
+	struct icc_node *n;
+	struct icc_req *r;
+	u32 avg_bw, peak_bw;
+
+	pr_info(" node                                  tag          avg         peak\n");
+	pr_info("--------------------------------------------------------------------\n");
+
+	list_for_each_entry(dp, &icc_providers, list) {
+		provider = dp->provider;
+
+		list_for_each_entry(n, &provider->nodes, node_list) {
+			if (!n->avg_bw && !n->peak_bw)
+				continue;
+
+			pr_info("%-42s %12u %12u\n",
+				n->name, n->avg_bw, n->peak_bw);
+
+			hlist_for_each_entry(r, &n->req_list, req_node) {
+				if (!r->dev)
+					continue;
+
+				if (r->enabled) {
+					avg_bw = r->avg_bw;
+					peak_bw = r->peak_bw;
+				} else {
+					avg_bw = 0;
+					peak_bw = 0;
+				}
+
+				if (avg_bw || peak_bw)
+					pr_info("  %-27s %12u %12u %12u\n",
+						dev_name(r->dev), r->tag, avg_bw, peak_bw);
+			}
+		}
+	}
+
+	return 0;
+}
+
+static int icc_debug_suspend_get(void *data, u64 *val)
+{
+	*val = debug_suspend;
+
+	return 0;
+}
+
+static void icc_debug_suspend_trace_probe(void *unused, const char *action,
+					  int val, bool start)
+{
+	if (start && val > 0 && !strcmp("machine_suspend", action)) {
+		pr_info("Enabled interconnect votes:\n");
+		icc_print_enabled();
+	}
+}
+
+static int icc_debug_suspend_set(void *data, u64 val)
+{
+	int ret;
+
+	val = !!val;
+	if (val == debug_suspend)
+		return 0;
+
+	if (val)
+		ret = register_trace_suspend_resume(icc_debug_suspend_trace_probe, NULL);
+	else
+		ret = unregister_trace_suspend_resume(icc_debug_suspend_trace_probe, NULL);
+
+	if (ret) {
+		pr_err("%s: Failed to %sregister suspend trace callback, ret=%d\n",
+		       __func__, val ? "" : "un", ret);
+		return ret;
+	}
+
+	debug_suspend = val;
+
+	return 0;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(icc_debug_suspend_fops, icc_debug_suspend_get,
+			 icc_debug_suspend_set, "%llu\n");
+
+int qcom_icc_debug_register(struct icc_provider *provider)
+{
+	struct qcom_icc_debug_provider *dp;
+
+	dp = kzalloc(sizeof(*dp), GFP_KERNEL);
+	if (!dp)
+		return -ENOMEM;
+
+	dp->provider = provider;
+
+	mutex_lock(&debug_lock);
+	list_add_tail(&dp->list, &icc_providers);
+	mutex_unlock(&debug_lock);
+
+	return 0;
+}
+EXPORT_SYMBOL(qcom_icc_debug_register);
+
+int qcom_icc_debug_unregister(struct icc_provider *provider)
+{
+	struct qcom_icc_debug_provider *dp, *temp;
+
+	mutex_lock(&debug_lock);
+
+	list_for_each_entry_safe(dp, temp, &icc_providers, list) {
+		if (dp->provider == provider) {
+			list_del(&dp->list);
+			kfree(dp);
+		}
+	}
+
+	mutex_unlock(&debug_lock);
+
+	return 0;
+}
+EXPORT_SYMBOL(qcom_icc_debug_unregister);
+
+static int __init qcom_icc_debug_init(void)
+{
+	static struct dentry *dir;
+	int ret;
+
+	dir = debugfs_lookup("interconnect", NULL);
+	if (IS_ERR_OR_NULL(dir)) {
+		ret = PTR_ERR(dir);
+		pr_err("%s: unable to find root interconnect debugfs directory, ret=%d\n",
+		       __func__, ret);
+		return 0;
+	}
+
+	dentry_suspend = debugfs_create_file_unsafe("debug_suspend",
+						    0644, dir, NULL,
+						    &icc_debug_suspend_fops);
+	return 0;
+}
+module_init(qcom_icc_debug_init);
+
+static void __exit qcom_icc_debug_exit(void)
+{
+	debugfs_remove(dentry_suspend);
+	if (debug_suspend)
+		unregister_trace_suspend_resume(icc_debug_suspend_trace_probe, NULL);
+}
+module_exit(qcom_icc_debug_exit);
+
+MODULE_DESCRIPTION("QCOM ICC debug library");
+MODULE_LICENSE("GPL v2");

drivers/interconnect/qcom/icc-debug.h

@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* Copyright (c) 2021, The Linux Foundation. All rights reserved. */
+
+#ifndef __QCOM_ICC_DEBUG_H__
+#define __QCOM_ICC_DEBUG_H__
+
+#include <linux/interconnect-provider.h>
+
+int qcom_icc_debug_register(struct icc_provider *provider);
+int qcom_icc_debug_unregister(struct icc_provider *provider);
+
+#endif

drivers/interconnect/qcom/icc-rpmh.c

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
- * Copyright (c) 2020, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2020-2021, The Linux Foundation. All rights reserved.
  */
 
 #include <linux/clk.h>
@@ -13,6 +13,7 @@
 #include <linux/slab.h>
 
 #include "bcm-voter.h"
+#include "icc-debug.h"
 #include "icc-rpmh.h"
 #include "qnoc-qos.h"
 
@@ -329,6 +330,8 @@ int qcom_icc_rpmh_probe(struct platform_device *pdev)
 	provider->set = qcom_icc_set;
 	provider->aggregate = qcom_icc_aggregate;
 
+	qcom_icc_debug_register(provider);
+
 	mutex_lock(&probe_list_lock);
 	list_add_tail(&qp->probe_list, &qnoc_probe_list);
 	mutex_unlock(&probe_list_lock);
@@ -347,6 +350,7 @@ int qcom_icc_rpmh_remove(struct platform_device *pdev)
 {
 	struct qcom_icc_provider *qp = platform_get_drvdata(pdev);
 
+	qcom_icc_debug_unregister(&qp->provider);
 	clk_bulk_put_all(qp->num_clks, qp->clks);
 
 	icc_nodes_remove(&qp->provider);