Message-ID: <46dbf7bb-9d5a-af50-7a76-d04df269eef6@quicinc.com>
Date: Fri, 5 Jan 2024 16:23:55 +0530
From: Krishna Chaitanya Chundru <quic_krichai@...cinc.com>
To: Baochen Qiang <quic_bqiang@...cinc.com>,
        Manivannan Sadhasivam
	<mani@...nel.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        Masami Hiramatsu
	<mhiramat@...nel.org>
CC: <linux-kernel@...r.kernel.org>, <mhi@...ts.linux.dev>,
        <linux-arm-msm@...r.kernel.org>, <linux-trace-kernel@...r.kernel.org>,
        <quic_vbadigan@...cinc.com>, <quic_ramkri@...cinc.com>,
        <quic_nitegupt@...cinc.com>, <quic_skananth@...cinc.com>,
        <quic_parass@...cinc.com>
Subject: Re: [PATCH v8] bus: mhi: host: Add tracing support


On 1/5/2024 10:47 AM, Baochen Qiang wrote:
>
>
> On 1/4/2024 12:47 PM, Krishna Chaitanya Chundru wrote:
>> Hi Steven,
>>
>> Can you please review this.
>>
>> Thanks & Regards,
>>
>> Krishna Chaitanya.
>>
>> On 12/7/2023 10:00 AM, 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.
> Is there a reason why debug messages have to be removed? From the view 
> of MHI controller, we often need MHI logs to debug, so is it possbile 
> to preserve those logs?

The trace is being replaced by the debug message and it would be 
preferred to have one mechanism or the other, not both.

you will still see these logs in traces.

- Krishna Chaitanya.

>>>
>>> Signed-off-by: Krishna chaitanya chundru <quic_krichai@...cinc.com>
>>> ---
>>> Changes in v8:
>>> - Pass the structure and derefernce the variables in TP_fast_assign 
>>> as suggested by steve
>>> - Link to v7: 
>>> https://lore.kernel.org/r/20231206-ftrace_support-v7-1-aca49a04268b@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  |  19 ++--
>>>   drivers/bus/mhi/host/pm.c    |   7 +-
>>>   drivers/bus/mhi/host/trace.h | 205 
>>> +++++++++++++++++++++++++++++++++++++++++++
>>>   4 files changed, 221 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..189f4786403e 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 +492,8 @@ 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, 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 +830,8 @@ 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, local_rp);
>>> +
>>>           switch (type) {
>>>           case MHI_PKT_TYPE_BW_REQ_EVENT:
>>>           {
>>> @@ -997,6 +997,8 @@ 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, local_rp);
>>> +
>>>           chan = MHI_TRE_GET_EV_CHID(local_rp);
>>>           WARN_ON(chan >= mhi_cntrl->max_chan);
>>> @@ -1235,6 +1237,7 @@ 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_chan, mhi_tre);
>>>       /* increment WP */
>>>       mhi_add_ring_element(mhi_cntrl, tre_ring);
>>>       mhi_add_ring_element(mhi_cntrl, buf_ring);
>>> @@ -1327,9 +1330,7 @@ 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_chan, to_state);
>>>       switch (to_state) {
>>>       case MHI_CH_STATE_TYPE_RESET:
>>>           write_lock_irq(&mhi_chan->lock);
>>> @@ -1396,9 +1397,7 @@ 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_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..5a2394b5b2e1 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, 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, 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..73c129bb91d9
>>> --- /dev/null
>>> +++ b/drivers/bus/mhi/host/trace.h
>>> @@ -0,0 +1,205 @@
>>> +/* 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(struct mhi_controller *mhi_cntrl, struct mhi_chan 
>>> *mhi_chan,
>>> +         struct mhi_ring_element *mhi_tre),
>>> +
>>> +    TP_ARGS(mhi_cntrl, mhi_chan, mhi_tre),
>>> +
>>> +    TP_STRUCT__entry(
>>> +        __string(name, mhi_cntrl->mhi_dev->name)
>>> +        __field(int, ch_num)
>>> +        __field(void *, wp)
>>> +        __field(__le64, tre_ptr)
>>> +        __field(__le32, dword0)
>>> +        __field(__le32, dword1)
>>> +    ),
>>> +
>>> +    TP_fast_assign(
>>> +        __assign_str(name, mhi_cntrl->mhi_dev->name);
>>> +        __entry->ch_num = mhi_chan->chan;
>>> +        __entry->wp = mhi_tre;
>>> +        __entry->tre_ptr = mhi_tre->ptr;
>>> +        __entry->dword0 = mhi_tre->dword[0];
>>> +        __entry->dword1 = mhi_tre->dword[1];
>>> +    ),
>>> +
>>> +    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(struct mhi_controller *mhi_cntrl, int dev_ee, int 
>>> dev_state),
>>> +
>>> +    TP_ARGS(mhi_cntrl, dev_ee, dev_state),
>>> +
>>> +    TP_STRUCT__entry(
>>> +        __string(name, mhi_cntrl->mhi_dev->name)
>>> +        __field(int, local_ee)
>>> +        __field(int, state)
>>> +        __field(int, dev_ee)
>>> +        __field(int, dev_state)
>>> +    ),
>>> +
>>> +    TP_fast_assign(
>>> +        __assign_str(name, mhi_cntrl->mhi_dev->name);
>>> +        __entry->local_ee = mhi_cntrl->ee;
>>> +        __entry->state = mhi_cntrl->dev_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(struct mhi_controller *mhi_cntrl, int pm_state),
>>> +
>>> +    TP_ARGS(mhi_cntrl, pm_state),
>>> +
>>> +    TP_STRUCT__entry(
>>> +        __string(name, mhi_cntrl->mhi_dev->name)
>>> +        __field(int, pm_state)
>>> +    ),
>>> +
>>> +    TP_fast_assign(
>>> +        __assign_str(name, mhi_cntrl->mhi_dev->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(struct mhi_controller *mhi_cntrl, struct 
>>> mhi_ring_element *rp),
>>> +
>>> +    TP_ARGS(mhi_cntrl, rp),
>>> +
>>> +    TP_STRUCT__entry(
>>> +        __string(name, mhi_cntrl->mhi_dev->name)
>>> +        __field(__le32, dword0)
>>> +        __field(__le32, dword1)
>>> +        __field(int, state)
>>> +        __field(__le64, ptr)
>>> +        __field(void *, rp)
>>> +    ),
>>> +
>>> +    TP_fast_assign(
>>> +        __assign_str(name, mhi_cntrl->mhi_dev->name);
>>> +        __entry->rp = rp;
>>> +        __entry->ptr = rp->ptr;
>>> +        __entry->dword0 = rp->dword[0];
>>> +        __entry->dword1 = rp->dword[1];
>>> +        __entry->state = MHI_TRE_GET_EV_STATE(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(struct mhi_controller *mhi_cntrl, struct 
>>> mhi_ring_element *rp),
>>> +
>>> +    TP_ARGS(mhi_cntrl, rp)
>>> +);
>>> +
>>> +DEFINE_EVENT(mhi_process_event_ring, mhi_ctrl_event,
>>> +
>>> +    TP_PROTO(struct mhi_controller *mhi_cntrl, struct 
>>> mhi_ring_element *rp),
>>> +
>>> +    TP_ARGS(mhi_cntrl, rp)
>>> +);
>>> +
>>> +DECLARE_EVENT_CLASS(mhi_update_channel_state,
>>> +
>>> +    TP_PROTO(struct mhi_controller *mhi_cntrl, struct mhi_chan 
>>> *mhi_chan, int state),
>>> +
>>> +    TP_ARGS(mhi_cntrl, mhi_chan, state),
>>> +
>>> +    TP_STRUCT__entry(
>>> +        __string(name, mhi_cntrl->mhi_dev->name)
>>> +        __field(int, ch_num)
>>> +        __field(int, state)
>>> +    ),
>>> +
>>> +    TP_fast_assign(
>>> +        __assign_str(name, mhi_cntrl->mhi_dev->name);
>>> +        __entry->ch_num = mhi_chan->chan;
>>> +        __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(struct mhi_controller *mhi_cntrl, struct mhi_chan 
>>> *mhi_chan, int state),
>>> +
>>> +    TP_ARGS(mhi_cntrl, mhi_chan, state)
>>> +);
>>> +
>>> +DEFINE_EVENT(mhi_update_channel_state, mhi_channel_command_end,
>>> +
>>> +    TP_PROTO(struct mhi_controller *mhi_cntrl, struct mhi_chan 
>>> *mhi_chan, int state),
>>> +
>>> +    TP_ARGS(mhi_cntrl, mhi_chan, state)
>>> +);
>>> +
>>> +TRACE_EVENT(mhi_pm_st_transition,
>>> +
>>> +    TP_PROTO(struct mhi_controller *mhi_cntrl, int state),
>>> +
>>> +    TP_ARGS(mhi_cntrl, state),
>>> +
>>> +    TP_STRUCT__entry(
>>> +        __string(name, mhi_cntrl->mhi_dev->name)
>>> +        __field(int, state)
>>> +    ),
>>> +
>>> +    TP_fast_assign(
>>> +        __assign_str(name, mhi_cntrl->mhi_dev->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,
>>

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