Re: [PATCH v2 3/3] usb: dwc3: Log dwc3 instance name in traces

[Prashanth K <prashanth.k@oss.qualcomm.com>]

On 1/9/2026 6:48 AM, Thinh Nguyen wrote:
> On Mon, Jan 05, 2026, Prashanth K wrote:
>> When multiple DWC3 controllers are being used, trace events from
>> different instances get mixed up making debugging difficult as
>> there's no way to distinguish which instance generated the trace.
>>
>> Append the base address of dwc3 controller to trace events, so that
>> the source instance is clearly identifiable.
>>
>> Example trace output,
>> before ->  dwc3_event: event (00000101): Reset [U0]
>> after  ->  dwc3_event: 0a600000: event (00000101): Reset [U0]
>>
>> Signed-off-by: Prashanth K <prashanth.k@oss.qualcomm.com>
>> ---
>>  drivers/usb/dwc3/core.c   |  6 ++-
>>  drivers/usb/dwc3/core.h   |  2 +
>>  drivers/usb/dwc3/ep0.c    |  2 +-
>>  drivers/usb/dwc3/gadget.c |  2 +-
>>  drivers/usb/dwc3/io.h     |  4 +-
>>  drivers/usb/dwc3/trace.h  | 88 ++++++++++++++++++++++++---------------
>>  6 files changed, 66 insertions(+), 38 deletions(-)
>>
>> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
>> index 670a9d4bfff2..3aa85f5f1c47 100644
>> --- a/drivers/usb/dwc3/core.c
>> +++ b/drivers/usb/dwc3/core.c
>> @@ -158,7 +158,7 @@ void dwc3_set_prtcap(struct dwc3 *dwc, u32 mode, bool ignore_susphy)
>>  	dwc3_writel(dwc, DWC3_GCTL, reg);
>>  
>>  	dwc->current_dr_role = mode;
>> -	trace_dwc3_set_prtcap(mode);
>> +	trace_dwc3_set_prtcap(dwc, mode);
>>  }
>>  EXPORT_SYMBOL_GPL(dwc3_set_prtcap);
>>  
>> @@ -2193,6 +2193,10 @@ int dwc3_core_probe(const struct dwc3_probe_data *data)
>>  	dwc_res = *res;
>>  	dwc_res.start += DWC3_GLOBALS_REGS_START;
>>  
>> +	/* Store the physical base address for logging in trace */
>> +	snprintf(dwc->base_addr, sizeof(dwc->base_addr), "%08llx",
>> +		 (unsigned long long)res->start);
>> +
> 
> Why string?
> 
>>  	if (dev->of_node) {
>>  		struct device_node *parent = of_get_parent(dev->of_node);
>>  
>> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
>> index 23188b910528..c16e47273ea0 100644
>> --- a/drivers/usb/dwc3/core.h
>> +++ b/drivers/usb/dwc3/core.h
>> @@ -1178,6 +1178,7 @@ struct dwc3_glue_ops {
>>   * @wakeup_pending_funcs: Indicates whether any interface has requested for
>>   *			 function wakeup in bitmap format where bit position
>>   *			 represents interface_id.
>> + * @base_addr: The HW base address of DWC3 controller.
>>   */
>>  struct dwc3 {
>>  	struct work_struct	drd_work;
>> @@ -1412,6 +1413,7 @@ struct dwc3 {
>>  	struct dentry		*debug_root;
>>  	u32			gsbuscfg0_reqinfo;
>>  	u32			wakeup_pending_funcs;
>> +	char			base_addr[9];
> 
> Can this be u32?
> 
Sure, will change it. And also rename it to dwc3_reg_base.
Let me know if that needs to be changed.

Regards,
Prashanth K