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Message-ID: <dbcd2f31-d4dc-12d8-7e32-911e07d7c7d1@quicinc.com>
Date: Fri, 5 Jan 2024 10:36:37 +0530
From: Krishna Chaitanya Chundru <quic_krichai@...cinc.com>
To: Steven Rostedt <rostedt@...dmis.org>
CC: Manivannan Sadhasivam <mani@...nel.org>,
Masami Hiramatsu
<mhiramat@...nel.org>,
<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 1/4/2024 9:31 PM, Steven Rostedt wrote:
> On Thu, 7 Dec 2023 10:00:47 +0530
> Krishna chaitanya chundru <quic_krichai@...cinc.com> 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@...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
> So this looks good from a tracing POV.
>
> Reviewed-by: Steven Rostedt (Google) <rostedt@...dmis.org>
>
> But I do have some more comments that could be done by new patches.
>
>
>
>> +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))
> So the above may have issues with user space parsing.
>
> For one, that mhi_state_str() is:
>
> static inline const char *mhi_state_str(enum mhi_state state)
> {
> switch (state) {
> case MHI_STATE_RESET:
> return "RESET";
> case MHI_STATE_READY:
> return "READY";
> case MHI_STATE_M0:
> return "M0";
> case MHI_STATE_M1:
> return "M1";
> case MHI_STATE_M2:
> return "M2";
> case MHI_STATE_M3:
> return "M3";
> case MHI_STATE_M3_FAST:
> return "M3 FAST";
> case MHI_STATE_BHI:
> return "BHI";
> case MHI_STATE_SYS_ERR:
> return "SYS ERROR";
> default:
> return "Unknown state";
> }
> };
>
> Which if this could be changed into:
>
> #define MHI_STATE_LIST \
> EM(RESET, "RESET") \
> EM(READY, "READY") \
> EM(M0, "M0") \
> EM(M1, "M1") \
> EM(M2, "M2") \
> EM(M3, "M3") \
> EM(M3_FAST, "M3_FAST") \
> EM(BHI, "BHI") \
> EMe(SYS_ERR, "SYS ERROR")
>
> #undef EM
> #undef EMe
>
> #define EM(a, b) case MHI_STATE_##a: return b;
> #define EMe(a, b) case MHI_STATE_##a: return b;
>
> static inline const char *mhi_state_str(enum mhi_state state)
> {
> switch (state) {
> MHI_STATE_LIST
> default:
> return "Unknown state";
> }
>
> Then you could use that macro in the trace header:
>
> #undef EM
> #undef EMe
>
> #define EM(a, b) TRACE_DEFINE_ENUM(MHI_STATE_##a);
> #define EMe(a, b) TRACE_DEFINE_ENUM(MHI_STATE_##a);
>
> MHI_STATE_LIST
>
> And in the print fmts:
>
> #undef EM
> #undef EMe
>
> #define EM(a, b) { MHI_STATE_##a, b },
> #define EMe(a, b) { MHI_STATE_##a, b }
>
>
> TP_printk("%s: local ee: %s state: %s device ee: %s state: %s\n",
> __get_str(name),
> TO_MHI_EXEC_STR(__entry->local_ee),
>
> __print_symbolic(__entry->state), MHI_STATE_LIST),
>
> TO_MHI_EXEC_STR(__entry->dev_ee),
>
> __print_symbolic(__entry->dev_state, MHI_STATE_LIST))
>
>
> And that will be exported to user space in the
> /sys/kernel/tracing/events/*/*/format file, as:
>
> __print_symbolic(REC->state, {
> { MHI_STATE_RESET, "RESET"},
> { MHI_STATE_READY, "READY"},
> { MHI_STATE_M0, "M0"},
> { MHI_STATE_M1, "M1"},
> { MHI_STATE_M2, "M2"},
> { MHI_STATE_M3, "M3"},
> { MHI_STATE_M3_FAST, "M3 FAST"},
> { MHI_STATE_BHI, "BHI"},
> { MHI_STATE_SYS_ERR, "SYS ERROR"} }
>
> Which libtracevent knows how to parse. Oh, it wouldn't even show the enum
> names as the TRACE_DEFINE_ENUM() above, would tell the kernel to replace
> them with their actual numeric values. That way, when trace-cmd or perf
> reads the raw data, it knows how to print it.
>
> Now what about those TO_MHI_EXEC_STR() macros? They are not the same. They are:
>
> #define TO_MHI_EXEC_STR(ee) (((ee) >= MHI_EE_MAX) ? \
> "INVALID_EE" : mhi_ee_str[ee])
>
> Where that mhi_ee_str[] is:
>
> const char * const mhi_ee_str[MHI_EE_MAX] = {
> [MHI_EE_PBL] = "PRIMARY BOOTLOADER",
> [MHI_EE_SBL] = "SECONDARY BOOTLOADER",
> [MHI_EE_AMSS] = "MISSION MODE",
> [MHI_EE_RDDM] = "RAMDUMP DOWNLOAD MODE",
> [MHI_EE_WFW] = "WLAN FIRMWARE",
> [MHI_EE_PTHRU] = "PASS THROUGH",
> [MHI_EE_EDL] = "EMERGENCY DOWNLOAD",
> [MHI_EE_FP] = "FLASH PROGRAMMER",
> [MHI_EE_DISABLE_TRANSITION] = "DISABLE",
> [MHI_EE_NOT_SUPPORTED] = "NOT SUPPORTED",
> };
>
> Which would require doing the same thing for that as well.
>
> #define MHI_EE_LIST \
> EM(PBL, "PRIMARY BOOTLOADER") \
> EM(SBL, "SECONDARY BOOTLOADER") \
> EM(AMSS, "MISSION MODE") \
> EM(RDDM, "RAMDUMP DOWNLOAD MODE")\
> EM(WFW, "WLAN FIRMWARE") \
> EM(PTHRU, "PASS THROUGH") \
> EM(EDL, "EMERGENCY DOWNLOAD") \
> EM(FP, "FLASH PROGRAMMER") \
> EM(DISABLE_TRANSITION, "DISABLE") \
> EMe(NOT_SUPPORTED, "NOT SUPPORTED")
>
> And have:
>
> #undef EM
> #undef EMe
>
> #define EM(a, b) [MHI_EE_##a] = b,
> #define EMe(a, b) [MHI_EE_##a] = b,
>
> const char * const mhi_ee_str[MHI_EE_MAX] = {
> MHI_EE_LIST
> };
>
> and so on. That way the user space parsing will know how to properly parse
> these events.
>
> Note, if you don't want to modify the other files, you can still just all
> the above to the trace.h file and it will still properly map the enums to
> the strings. That is, don't modify the mhi_ee_str(), but instead just add
> the MHI_EE_LIST macro in the trace header, and use the __print_symbolic()
> with it.
>
> I only mentioned modifying the strings to make it consistent if new strings
> are added.
>
> -- Steve
Thanks steve for the these inputs, we will try these and will update as
suggested in the next patch.
- Krishna chaitanya
>
>> +);
>> +
>> +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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