Date: Fri, 5 Jan 2024 13:17:20 +0800
From: Baochen Qiang <quic_bqiang@...cinc.com>
To: Krishna Chaitanya Chundru <quic_krichai@...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 1/4/2024 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?
>>
>> 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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