Re: [PATCH v5] bus: mhi: host: Add tracing support

[Manivannan Sadhasivam <mani@kernel.org>]

On Mon, Nov 27, 2023 at 04:39:12PM +0530, Krishna chaitanya chundru wrote:
> 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 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/internal.h |   1 +
>  drivers/bus/mhi/host/main.c     |  23 +++--
>  drivers/bus/mhi/host/pm.c       |   6 +-
>  drivers/bus/mhi/host/trace.h    | 208 ++++++++++++++++++++++++++++++++++++++++
>  5 files changed, 228 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/internal.h b/drivers/bus/mhi/host/internal.h
> index 2e139e76de4c..a02a71605907 100644
> --- a/drivers/bus/mhi/host/internal.h
> +++ b/drivers/bus/mhi/host/internal.h
> @@ -7,6 +7,7 @@
>  #ifndef _MHI_INT_H
>  #define _MHI_INT_H
>  
> +#include "trace.h"

Please include header in files where it is actually used.

>  #include "../common.h"
>  
>  extern struct bus_type mhi_bus_type;
> diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c
> index dcf627b36e82..0d7e068e713a 100644
> --- a/drivers/bus/mhi/host/main.c
> +++ b/drivers/bus/mhi/host/main.c
> @@ -491,11 +491,9 @@ 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 +830,10 @@ 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 +999,9 @@ 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 +1240,8 @@ 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 +1334,7 @@ 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 +1401,7 @@ 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..e32afdc92fde 100644
> --- a/drivers/bus/mhi/host/pm.c
> +++ b/drivers/bus/mhi/host/pm.c
> @@ -123,6 +123,7 @@ 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 +754,6 @@ 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 +761,8 @@ 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..3bfac529c6b7
> --- /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 WP: 0x%p TRE: 0x%llx 0x%08x 0x%08x\n",o

What you are printing as TRE is not actually a TRE but the data pointer
referenced by the TRE. WP is the actual TRE.

> +		  __get_str(name), __entry->ch_num, __entry->wp, __entry->tre_ptr,
> +		  __entry->dword0, __entry->dword1)

DWORDs are getting printed without any name. Like,

mhi_gen_tre: mhi0: Chan: 46 WP: 0x00000000bcd06579 TRE: 0xffbcf190 0x0000004c 0x00020200

> +);
> +
> +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 *)entry->rp);
> +	),
> +
> +	TP_printk("%s: RP:0x%p Processing Event:0x%llx 0x%08x 0x%08x state:%s\n",

Same comment as above. Also, please use a single format. Like, here you are
printing "Processing Event" after "RP"...

> +		  __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: ch%d: Updating state to: %s\n",

Use "Chan" as above.

> +		  __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 .

I had to use relative path to build this patch:

#define TRACE_INCLUDE_PATH ../../drivers/bus/mhi/host

- Mani

> +#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>
> 
> 

-- 
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