soc: qcom: Add debugfs interface for enabling SOC debug events

Other processors/execution environments may support debug events. Implement
an 'smc instruction' based communications protocol and hook it up to
debugfs.

Change-Id: I3a99dfdac5df7edb874bd449d9abc5a929787758
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>

4 files changed, 241 insertions, 1 deletions

diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
index 99f625d18ea9..d238b725b834 100644
--- a/drivers/soc/qcom/Kconfig
+++ b/drivers/soc/qcom/Kconfig
@@ -582,4 +582,13 @@ config MSM_CORE_CTL_HELPER
 	  system load and state. It also supports limiting min and
 	  max online CPUs from userspace.
 
+config MSM_REMOTEQDSS
+	bool "Allow debug tools to enable events on other processors"
+	depends on MSM_SCM && DEBUG_FS
+	help
+	  Other onchip processors/execution environments may support debug
+	  events. Provide a sysfs interface for debug tools to dynamically
+	  enable/disable these events. Interface located in
+	  /sys/class/remoteqdss.
+
 source "drivers/soc/qcom/memshare/Kconfig"
diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
index d03598a342d8..75f80e19029a 100644
--- a/drivers/soc/qcom/Makefile
+++ b/drivers/soc/qcom/Makefile
@@ -79,3 +79,4 @@ obj-$(CONFIG_MSM_AVTIMER) += avtimer.o
 obj-$(CONFIG_HW_PERF_EVENTS) += perf_event_kryo.o
 obj-$(CONFIG_MSM_KERNEL_PROTECT) += kernel_protect.o
 obj-$(CONFIG_MSM_RTB) += msm_rtb-hotplug.o
+obj-$(CONFIG_MSM_REMOTEQDSS) += remoteqdss.o
diff --git a/drivers/soc/qcom/remoteqdss.c b/drivers/soc/qcom/remoteqdss.c
new file mode 100644
index 000000000000..bb10099db83f
--- /dev/null
+++ b/drivers/soc/qcom/remoteqdss.c
@@ -0,0 +1,228 @@
+/*
+ * Copyright (c) 2015-2016, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <soc/qcom/scm.h>
+#include <linux/debugfs.h>
+#include <linux/ratelimit.h>
+
+#define REMOTEQDSS_FLAG_QUIET (BIT(0))
+
+static unsigned long remoteqdss_dbg_flags;
+module_param_named(dbg_flags, remoteqdss_dbg_flags, ulong, 0644);
+
+static struct dentry *remoteqdss_dir;
+
+#define REMOTEQDSS_ERR(fmt, ...) \
+	pr_err("%s: " fmt, __func__, ## __VA_ARGS__)
+
+#define REMOTEQDSS_ERR_CALLER(fmt, ...) \
+	pr_err("%pf: " fmt, __builtin_return_address(0), ## __VA_ARGS__)
+
+struct qdss_msg_translation {
+	u64 val;
+	char *msg;
+};
+
+/*
+ * id			Unique identifier
+ * sw_entity_group	Array index
+ * sw_event_group	Array index
+ * dir			Parent debugfs directory
+ */
+struct remoteqdss_data {
+	u8 id;
+	u64 sw_entity_group;
+	u64 sw_event_group;
+	struct dentry *dir;
+};
+
+/* msgs is a null terminated array */
+static void remoteqdss_err_translation(struct qdss_msg_translation *msgs,
+								u64 err)
+{
+	static DEFINE_RATELIMIT_STATE(rl, 5 * HZ, 2);
+	struct qdss_msg_translation *msg;
+
+	if (!err)
+		return;
+
+	if (remoteqdss_dbg_flags & REMOTEQDSS_FLAG_QUIET)
+		return;
+
+	for (msg = msgs; msg->msg; msg++) {
+		if (err == msg->val && __ratelimit(&rl)) {
+			REMOTEQDSS_ERR_CALLER("0x%llx: %s\n", err, msg->msg);
+			return;
+		}
+	}
+
+	REMOTEQDSS_ERR_CALLER("Error 0x%llx\n", err);
+}
+
+/* SCM based devices */
+#define SCM_FILTER_SWTRACE_ID (0x1)
+#define SCM_QUERY_SWTRACE_ID  (0x2)
+
+/* Response Values */
+#define SCM_CMD_FAIL		(0x80)
+#define SCM_QDSS_UNAVAILABLE	(0x81)
+#define SCM_UNINITIALIZED	(0x82)
+#define SCM_BAD_ARG		(0x83)
+#define SCM_BAD_SUBSYS		(0x85)
+
+static struct qdss_msg_translation remoteqdss_scm_msgs[] = {
+	{SCM_CMD_FAIL,
+		"Command failed"},
+	{SCM_QDSS_UNAVAILABLE,
+		"QDSS not available or cannot turn QDSS (clock) on"},
+	{SCM_UNINITIALIZED,
+		"Tracer not initialized or unable to initialize"},
+	{SCM_BAD_ARG,
+		"Invalid parameter value"},
+	{SCM_BAD_SUBSYS,
+		"Incorrect subsys ID"},
+	{}
+};
+
+static struct remoteqdss_data *create_remoteqdss_data(u32 id)
+{
+	struct remoteqdss_data *data;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return NULL;
+
+	data->id = id;
+	return data;
+}
+
+static void free_remoteqdss_data(struct remoteqdss_data *data)
+{
+	kfree(data);
+}
+
+static int remoteqdss_scm_query_swtrace(void *priv, u64 *val)
+{
+	struct remoteqdss_data *data = priv;
+	int ret;
+	struct scm_desc desc;
+
+	memset(&desc, 0, sizeof(desc));
+	desc.args[0] = data->id;
+	desc.arginfo = SCM_ARGS(1, SCM_VAL);
+
+	ret = scm_call2(
+		SCM_SIP_FNID(SCM_SVC_QDSS, SCM_QUERY_SWTRACE_ID),
+		&desc);
+	if (ret)
+		return ret;
+
+	remoteqdss_err_translation(remoteqdss_scm_msgs, desc.ret[0]);
+	ret = desc.ret[0] ? -EINVAL : 0;
+	*val = desc.ret[1];
+	return ret;
+}
+
+static int remoteqdss_scm_filter_swtrace(void *priv, u64 val)
+{
+	struct remoteqdss_data *data = priv;
+	int ret;
+	struct scm_desc desc;
+
+	memset(&desc, 0, sizeof(desc));
+	desc.args[0] = data->id;
+	desc.args[1] = val;
+	desc.arginfo = SCM_ARGS(2, SCM_VAL, SCM_VAL);
+
+	ret = scm_call2(
+		SCM_SIP_FNID(SCM_SVC_QDSS, SCM_FILTER_SWTRACE_ID),
+		&desc);
+	if (ret)
+		return ret;
+
+	remoteqdss_err_translation(remoteqdss_scm_msgs, desc.ret[0]);
+	ret = desc.ret[0] ? -EINVAL : 0;
+	return ret;
+}
+DEFINE_SIMPLE_ATTRIBUTE(fops_sw_trace_output,
+			remoteqdss_scm_query_swtrace,
+			remoteqdss_scm_filter_swtrace,
+			"%llu\n");
+
+static void __init enumerate_scm_devices(struct dentry *parent)
+{
+	u64 unused;
+	int ret;
+	struct remoteqdss_data *data;
+	struct dentry *dentry;
+
+	if (!is_scm_armv8())
+		return;
+
+	data = create_remoteqdss_data(0);
+	if (!data)
+		return;
+
+	/* Assume failure means device not present */
+	ret = remoteqdss_scm_query_swtrace(data, &unused);
+	if (ret)
+		goto out;
+
+	data->dir = debugfs_create_dir("tz", parent);
+	if (IS_ERR_OR_NULL(data->dir))
+		goto out;
+
+	dentry = debugfs_create_file("sw_trace_output", S_IRUGO | S_IWUSR,
+			data->dir, data, &fops_sw_trace_output);
+	if (IS_ERR_OR_NULL(dentry))
+		goto out;
+
+	dentry = debugfs_create_u64("sw_entity_group", S_IRUGO | S_IWUSR,
+			data->dir, &data->sw_entity_group);
+	if (IS_ERR_OR_NULL(dentry))
+		goto out;
+
+	dentry = debugfs_create_u64("sw_event_group", S_IRUGO | S_IWUSR,
+			data->dir, &data->sw_event_group);
+	if (IS_ERR_OR_NULL(dentry))
+		goto out;
+
+	return;
+
+out:
+	debugfs_remove_recursive(data->dir);
+	free_remoteqdss_data(data);
+}
+
+static int __init remoteqdss_init(void)
+{
+	unsigned long old_flags = remoteqdss_dbg_flags;
+
+	/*
+	 * disable normal error messages while checking
+	 * if support is present.
+	 */
+	remoteqdss_dbg_flags |= REMOTEQDSS_FLAG_QUIET;
+
+	remoteqdss_dir = debugfs_create_dir("remoteqdss", NULL);
+	if (!remoteqdss_dir)
+		return 0;
+
+	enumerate_scm_devices(remoteqdss_dir);
+
+	remoteqdss_dbg_flags = old_flags;
+	return 0;
+}
+module_init(remoteqdss_init);
diff --git a/include/soc/qcom/scm.h b/include/soc/qcom/scm.h
index 97cea4792528..f6791ac9dc32 100644
--- a/include/soc/qcom/scm.h
+++ b/include/soc/qcom/scm.h
@@ -1,4 +1,4 @@
-/* Copyright (c) 2010-2015, The Linux Foundation. All rights reserved.
+/* Copyright (c) 2010-2016, The Linux Foundation. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 and
@@ -27,6 +27,8 @@
 #define SCM_SVC_HDCP			0x11
 #define SCM_SVC_MDTP			0x12
 #define SCM_SVC_LMH			0x13
+#define SCM_SVC_SMMU_PROGRAM		0x15
+#define SCM_SVC_QDSS			0x16
 #define SCM_SVC_TZSCHEDULER		0xFC
 
 #define SCM_FUSE_READ			0x7