[PATCH v7] bus: mhi: host: Add tracing support

[Krishna chaitanya chundru <quic_krichai@quicinc.com>]

This change adds ftrace support for following functions which
helps in debugging the issues when there is Channel state & MHI
state change and also when we receive data and control events:
1. mhi_intvec_mhi_states
2. mhi_process_data_event_ring
3. mhi_process_ctrl_ev_ring
4. mhi_gen_tre
5. mhi_update_channel_state
6. mhi_tryset_pm_state
7. mhi_pm_st_worker

Where ever the trace events are added, debug messages are removed.

Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
---
Changes in v7:
- change log format as pointed by mani.
- Link to v6: https://lore.kernel.org/r/20231204-ftrace_support-v6-1-9b206546dac2@quicinc.com

Changes in v6:
- use 'rp' directly as suggested by jeffrey.
- Link to v5: https://lore.kernel.org/r/20231127-ftrace_support-v5-1-eb67daead4f1@quicinc.com

Changes in v5:
- Use DECLARE_EVENT_CLASS for multiple events as suggested by steve.
- Instead of converting to u64 to print address, use %px to print the address to avoid
- warnings in some platforms.
- Link to v4: https://lore.kernel.org/r/20231111-ftrace_support-v4-1-c83602399461@quicinc.com

Changes in v4:
- Fix compilation issues in previous patch which happended due to rebasing.
- In the defconfig FTRACE config is not enabled due to that the compilation issue is not
- seen in my workspace.
- Link to v3: https://lore.kernel.org/r/20231111-ftrace_support-v3-1-f358d2911a74@quicinc.com

Changes in v3:
- move trace header file from include/trace/events to drivers/bus/mhi/host/ so that
- we can include driver header files.
- Use macros directly in the trace events as suggested Jeffrey Hugo.
- Reorder the structure in the events as suggested by steve to avoid holes in the buffer.
- removed the mhi_to_physical function as this can give security issues.
- removed macros to define strings as we can get those from driver headers.
- Link to v2: https://lore.kernel.org/r/20231013-ftrace_support-v2-1-6e893ce010b5@quicinc.com

Changes in v2:
- Passing the raw state into the trace event and using  __print_symbolic() as suggested by bjorn.
- Change mhi_pm_st_worker to mhi_pm_st_transition as suggested by bjorn.
- Fixed the kernel test rebot issues.
- Link to v1: https://lore.kernel.org/r/20231005-ftrace_support-v1-1-23a2f394fa49@quicinc.com
---
 drivers/bus/mhi/host/init.c  |   3 +
 drivers/bus/mhi/host/main.c  |  24 ++---
 drivers/bus/mhi/host/pm.c    |   7 +-
 drivers/bus/mhi/host/trace.h | 208 +++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 229 insertions(+), 13 deletions(-)

diff --git a/drivers/bus/mhi/host/init.c b/drivers/bus/mhi/host/init.c
index f78aefd2d7a3..6acb85f4c5f8 100644
--- a/drivers/bus/mhi/host/init.c
+++ b/drivers/bus/mhi/host/init.c
@@ -20,6 +20,9 @@
 #include <linux/wait.h>
 #include "internal.h"
 
+#define CREATE_TRACE_POINTS
+#include "trace.h"
+
 static DEFINE_IDA(mhi_controller_ida);
 
 const char * const mhi_ee_str[MHI_EE_MAX] = {
diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c
index dcf627b36e82..507cf3351a97 100644
--- a/drivers/bus/mhi/host/main.c
+++ b/drivers/bus/mhi/host/main.c
@@ -15,6 +15,7 @@
 #include <linux/skbuff.h>
 #include <linux/slab.h>
 #include "internal.h"
+#include "trace.h"
 
 int __must_check mhi_read_reg(struct mhi_controller *mhi_cntrl,
 			      void __iomem *base, u32 offset, u32 *out)
@@ -491,11 +492,9 @@ irqreturn_t mhi_intvec_threaded_handler(int irq_number, void *priv)
 
 	state = mhi_get_mhi_state(mhi_cntrl);
 	ee = mhi_get_exec_env(mhi_cntrl);
-	dev_dbg(dev, "local ee: %s state: %s device ee: %s state: %s\n",
-		TO_MHI_EXEC_STR(mhi_cntrl->ee),
-		mhi_state_str(mhi_cntrl->dev_state),
-		TO_MHI_EXEC_STR(ee), mhi_state_str(state));
 
+	trace_mhi_intvec_states(mhi_cntrl->mhi_dev->name, mhi_cntrl->ee,
+				mhi_cntrl->dev_state, ee, state);
 	if (state == MHI_STATE_SYS_ERR) {
 		dev_dbg(dev, "System error detected\n");
 		pm_state = mhi_tryset_pm_state(mhi_cntrl,
@@ -832,6 +831,10 @@ int mhi_process_ctrl_ev_ring(struct mhi_controller *mhi_cntrl,
 	while (dev_rp != local_rp) {
 		enum mhi_pkt_type type = MHI_TRE_GET_EV_TYPE(local_rp);
 
+		trace_mhi_ctrl_event(mhi_cntrl->mhi_dev->name, local_rp,
+				     local_rp->ptr, local_rp->dword[0],
+				     local_rp->dword[1]);
+
 		switch (type) {
 		case MHI_PKT_TYPE_BW_REQ_EVENT:
 		{
@@ -997,6 +1000,9 @@ int mhi_process_data_event_ring(struct mhi_controller *mhi_cntrl,
 	while (dev_rp != local_rp && event_quota > 0) {
 		enum mhi_pkt_type type = MHI_TRE_GET_EV_TYPE(local_rp);
 
+		trace_mhi_data_event(mhi_cntrl->mhi_dev->name, local_rp, local_rp->ptr,
+				     local_rp->dword[0], local_rp->dword[1]);
+
 		chan = MHI_TRE_GET_EV_CHID(local_rp);
 
 		WARN_ON(chan >= mhi_cntrl->max_chan);
@@ -1235,6 +1241,8 @@ int mhi_gen_tre(struct mhi_controller *mhi_cntrl, struct mhi_chan *mhi_chan,
 	mhi_tre->dword[0] = MHI_TRE_DATA_DWORD0(info->len);
 	mhi_tre->dword[1] = MHI_TRE_DATA_DWORD1(bei, eot, eob, chain);
 
+	trace_mhi_gen_tre(mhi_cntrl->mhi_dev->name, mhi_chan->chan, mhi_tre,
+			  mhi_tre->ptr, mhi_tre->dword[0], mhi_tre->dword[1]);
 	/* increment WP */
 	mhi_add_ring_element(mhi_cntrl, tre_ring);
 	mhi_add_ring_element(mhi_cntrl, buf_ring);
@@ -1327,9 +1335,7 @@ static int mhi_update_channel_state(struct mhi_controller *mhi_cntrl,
 	enum mhi_cmd_type cmd = MHI_CMD_NOP;
 	int ret;
 
-	dev_dbg(dev, "%d: Updating channel state to: %s\n", mhi_chan->chan,
-		TO_CH_STATE_TYPE_STR(to_state));
-
+	trace_mhi_channel_command_start(mhi_cntrl->mhi_dev->name, mhi_chan->chan, to_state);
 	switch (to_state) {
 	case MHI_CH_STATE_TYPE_RESET:
 		write_lock_irq(&mhi_chan->lock);
@@ -1396,9 +1402,7 @@ static int mhi_update_channel_state(struct mhi_controller *mhi_cntrl,
 		write_unlock_irq(&mhi_chan->lock);
 	}
 
-	dev_dbg(dev, "%d: Channel state change to %s successful\n",
-		mhi_chan->chan, TO_CH_STATE_TYPE_STR(to_state));
-
+	trace_mhi_channel_command_end(mhi_cntrl->mhi_dev->name, mhi_chan->chan, to_state);
 exit_channel_update:
 	mhi_cntrl->runtime_put(mhi_cntrl);
 	mhi_device_put(mhi_cntrl->mhi_dev);
diff --git a/drivers/bus/mhi/host/pm.c b/drivers/bus/mhi/host/pm.c
index 8a4362d75fc4..dd958f58ad1c 100644
--- a/drivers/bus/mhi/host/pm.c
+++ b/drivers/bus/mhi/host/pm.c
@@ -15,6 +15,7 @@
 #include <linux/slab.h>
 #include <linux/wait.h>
 #include "internal.h"
+#include "trace.h"
 
 /*
  * Not all MHI state transitions are synchronous. Transitions like Linkdown,
@@ -123,6 +124,7 @@ enum mhi_pm_state __must_check mhi_tryset_pm_state(struct mhi_controller *mhi_cn
 	if (unlikely(!(dev_state_transitions[index].to_states & state)))
 		return cur_state;
 
+	trace_mhi_tryset_pm_state(mhi_cntrl->mhi_dev->name, state);
 	mhi_cntrl->pm_state = state;
 	return mhi_cntrl->pm_state;
 }
@@ -753,7 +755,6 @@ void mhi_pm_st_worker(struct work_struct *work)
 	struct mhi_controller *mhi_cntrl = container_of(work,
 							struct mhi_controller,
 							st_worker);
-	struct device *dev = &mhi_cntrl->mhi_dev->dev;
 
 	spin_lock_irq(&mhi_cntrl->transition_lock);
 	list_splice_tail_init(&mhi_cntrl->transition_list, &head);
@@ -761,8 +762,8 @@ void mhi_pm_st_worker(struct work_struct *work)
 
 	list_for_each_entry_safe(itr, tmp, &head, node) {
 		list_del(&itr->node);
-		dev_dbg(dev, "Handling state transition: %s\n",
-			TO_DEV_STATE_TRANS_STR(itr->state));
+
+		trace_mhi_pm_st_transition(mhi_cntrl->mhi_dev->name, itr->state);
 
 		switch (itr->state) {
 		case DEV_ST_TRANSITION_PBL:
diff --git a/drivers/bus/mhi/host/trace.h b/drivers/bus/mhi/host/trace.h
new file mode 100644
index 000000000000..438862f3ffdf
--- /dev/null
+++ b/drivers/bus/mhi/host/trace.h
@@ -0,0 +1,208 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM mhi_host
+
+#if !defined(_TRACE_EVENT_MHI_HOST_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_EVENT_MHI_HOST_H
+
+#include <linux/tracepoint.h>
+#include <linux/trace_seq.h>
+#include "../common.h"
+#include "internal.h"
+
+TRACE_EVENT(mhi_gen_tre,
+
+	TP_PROTO(const char *name, int ch_num, void *wp, __le64 tre_ptr,
+		 __le32 dword0, __le32 dword1),
+
+	TP_ARGS(name, ch_num, wp, tre_ptr, dword0, dword1),
+
+	TP_STRUCT__entry(
+		__string(name, name)
+		__field(int, ch_num)
+		__field(void *, wp)
+		__field(__le64, tre_ptr)
+		__field(__le32, dword0)
+		__field(__le32, dword1)
+	),
+
+	TP_fast_assign(
+		__assign_str(name, name);
+		__entry->ch_num = ch_num;
+		__entry->wp = wp;
+		__entry->tre_ptr = tre_ptr;
+		__entry->dword0 = dword0;
+		__entry->dword1 = dword1;
+	),
+
+	TP_printk("%s: Chan: %d Tre: 0x%p Tre buf: 0x%llx dword0: 0x%08x dword1: 0x%08x\n",
+		  __get_str(name), __entry->ch_num, __entry->wp, __entry->tre_ptr,
+		  __entry->dword0, __entry->dword1)
+);
+
+TRACE_EVENT(mhi_intvec_states,
+
+	TP_PROTO(const char *name, int local_ee, int state, int dev_ee, int dev_state),
+
+	TP_ARGS(name, local_ee, state, dev_ee, dev_state),
+
+	TP_STRUCT__entry(
+		__string(name, name)
+		__field(int, local_ee)
+		__field(int, state)
+		__field(int, dev_ee)
+		__field(int, dev_state)
+	),
+
+	TP_fast_assign(
+		__assign_str(name, name);
+		__entry->local_ee = local_ee;
+		__entry->state = state;
+		__entry->dev_ee = dev_ee;
+		__entry->dev_state = dev_state;
+	),
+
+	TP_printk("%s: local ee: %s state: %s device ee: %s state: %s\n",
+		  __get_str(name),
+		  TO_MHI_EXEC_STR(__entry->local_ee),
+		  mhi_state_str(__entry->state),
+		  TO_MHI_EXEC_STR(__entry->dev_ee),
+		  mhi_state_str(__entry->dev_state))
+);
+
+TRACE_EVENT(mhi_tryset_pm_state,
+
+	TP_PROTO(const char *name, int pm_state),
+
+	TP_ARGS(name, pm_state),
+
+	TP_STRUCT__entry(
+		__string(name, name)
+		__field(int, pm_state)
+	),
+
+	TP_fast_assign(
+		__assign_str(name, name);
+		if (pm_state)
+			pm_state = __fls(pm_state);
+		__entry->pm_state = pm_state;
+	),
+
+	TP_printk("%s: PM state: %s\n", __get_str(name),
+		  to_mhi_pm_state_str(__entry->pm_state))
+);
+
+DECLARE_EVENT_CLASS(mhi_process_event_ring,
+
+	TP_PROTO(const char *name, void *rp, __le64 ptr,
+		 __le32 dword0, __le32 dword1),
+
+	TP_ARGS(name, rp, ptr, dword0, dword1),
+
+	TP_STRUCT__entry(
+		__string(name, name)
+		__field(__le32, dword0)
+		__field(__le32, dword1)
+		__field(int, state)
+		__field(__le64, ptr)
+		__field(void *, rp)
+	),
+
+	TP_fast_assign(
+		__assign_str(name, name);
+		__entry->rp = rp;
+		__entry->ptr = ptr;
+		__entry->dword0 = dword0;
+		__entry->dword1 = dword1;
+		__entry->state = MHI_TRE_GET_EV_STATE((struct mhi_ring_element *)rp);
+	),
+
+	TP_printk("%s: Tre: 0x%p Tre buf: 0x%llx dword0: 0x%08x dword1: 0x%08x state: %s\n",
+		  __get_str(name), __entry->rp, __entry->ptr, __entry->dword0,
+		  __entry->dword1, mhi_state_str(__entry->state))
+);
+
+DEFINE_EVENT(mhi_process_event_ring, mhi_data_event,
+
+	TP_PROTO(const char *name, void *rp, __le64 ptr,
+		 __le32 dword0, __le32 dword1),
+
+	TP_ARGS(name, rp, ptr, dword0, dword1)
+);
+
+DEFINE_EVENT(mhi_process_event_ring, mhi_ctrl_event,
+
+	TP_PROTO(const char *name, void *rp, __le64 ptr,
+		 __le32 dword0, __le32 dword1),
+
+	TP_ARGS(name, rp, ptr, dword0, dword1)
+);
+
+DECLARE_EVENT_CLASS(mhi_update_channel_state,
+
+	TP_PROTO(const char *name, int ch_num, int state),
+
+	TP_ARGS(name, ch_num, state),
+
+	TP_STRUCT__entry(
+		__string(name, name)
+		__field(int, ch_num)
+		__field(int, state)
+	),
+
+	TP_fast_assign(
+		__assign_str(name, name);
+		__entry->ch_num = ch_num;
+		__entry->state = state;
+	),
+
+	TP_printk("%s: chan%d: Updating state to: %s\n",
+		  __get_str(name), __entry->ch_num,
+		  TO_CH_STATE_TYPE_STR(__entry->state))
+);
+
+DEFINE_EVENT(mhi_update_channel_state, mhi_channel_command_start,
+
+	TP_PROTO(const char *name, int ch_num, int state),
+
+	TP_ARGS(name, ch_num, state)
+);
+
+DEFINE_EVENT(mhi_update_channel_state, mhi_channel_command_end,
+
+	TP_PROTO(const char *name, int ch_num, int state),
+
+	TP_ARGS(name, ch_num, state)
+);
+
+TRACE_EVENT(mhi_pm_st_transition,
+
+	TP_PROTO(const char *name, int state),
+
+	TP_ARGS(name, state),
+
+	TP_STRUCT__entry(
+		__string(name, name)
+		__field(int, state)
+	),
+
+	TP_fast_assign(
+		__assign_str(name, name);
+		__entry->state = state;
+	),
+
+	TP_printk("%s: Handling state transition: %s\n", __get_str(name),
+		  TO_DEV_STATE_TRANS_STR(__entry->state))
+);
+
+#endif
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH ../../drivers/bus/mhi/host
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE trace
+
+#include <trace/define_trace.h>

---
base-commit: 3006adf3be79cde4d14b1800b963b82b6e5572e0
change-id: 20231005-ftrace_support-6869d4156139

Best regards,
-- 
Krishna chaitanya chundru <quic_krichai@quicinc.com>