[6/6] dma: tegra: add tracepoint for residual update

[Ben Dooks <ben.dooks@codethink.co.uk>]

On 2018-10-12 18:04, Steven Rostedt wrote:
> On Fri, 12 Oct 2018 10:44:54 +0100
> Ben Dooks <ben.dooks@codethink.co.uk> wrote:
> 
>> Add a tracepoint in the residual update instead of using dev_dbg()
>> to allow debugging via the trace pipe.
>> 
>> Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
>> ---
>> Cc: Ingo Molnar <mingo@redhat.com> (maintainer:TRACING)
>> Cc: Steven Rostedt <rostedt@goodmis.org> (maintainer:TRACING)
>> ---
>>  drivers/dma/tegra20-apb-dma.c        |  5 ++---
>>  include/trace/events/tegra_apb_dma.h | 27 +++++++++++++++++++++++++++
>>  2 files changed, 29 insertions(+), 3 deletions(-)
>> 
>> diff --git a/drivers/dma/tegra20-apb-dma.c 
>> b/drivers/dma/tegra20-apb-dma.c
>> index 96095a3b7edd..495cda6c21b9 100644
>> --- a/drivers/dma/tegra20-apb-dma.c
>> +++ b/drivers/dma/tegra20-apb-dma.c
>> @@ -886,9 +886,8 @@ static unsigned int 
>> tegra_dma_update_residual(struct tegra_dma_channel *tdc,
>>  	}
>> 
>>  done:
>> -	dev_dbg(tdc2dev(tdc), "residual: req %08lx, ahb@%08lx, wcount %08lx, 
>> done %d\n",
>> -		 sg_req->ch_regs.ahb_ptr, ahbptr, wcount, done);
>> -
>> +	trace_tegra_dma_tx_state(&tdc->dma_chan, ahbptr, status, result,
>> +				 tmp, residual);
>>  	return result;
>>  }
>> 
>> diff --git a/include/trace/events/tegra_apb_dma.h 
>> b/include/trace/events/tegra_apb_dma.h
>> index 80d6f0cf4c36..a686f98a9c8b 100644
>> --- a/include/trace/events/tegra_apb_dma.h
>> +++ b/include/trace/events/tegra_apb_dma.h
>> @@ -43,6 +43,33 @@ TRACE_EVENT(tegra_dma_complete_cb,
>>  		      __entry->count, __entry->ptr)
>>  );
>> 
>> +TRACE_EVENT(tegra_dma_tx_state,
>> +	    TP_PROTO(struct dma_chan *dc, unsigned long ahb,
>> +		     unsigned long wc, unsigned int done,
>> +		     unsigned long byte_count, unsigned int residual),
>> +	    TP_ARGS(dc, ahb, wc, done, byte_count, residual),
>> +	    TP_STRUCT__entry(
>> +		    __field(struct dma_chan *,	dc)
>> +		    __field(unsigned long,	ahb)
>> +		    __field(unsigned long,	wc)
>> +		    __field(unsigned long,	done)
>> +		    __field(unsigned int,	residual)
>> +		    __field(unsigned long,	byte_count)
>> +		    ),
>> +	    TP_fast_assign(
>> +		    __entry->dc = dc;
>> +		    __entry->ahb = ahb;
>> +		    __entry->wc = wc;
>> +		    __entry->done = done;
>> +		    __entry->residual = residual;
>> +		    __entry->byte_count = byte_count;
>> +		    ),
>> +	    TP_printk("%s: txresidual: ahb %08lx wc %08lx => done %lu bc %lu 
>> residual %u",
>> +		      dev_name(&__entry->dc->dev->device),
> 
> Here too. Move the dev_name() up into TP_fast_assign() which gets
> executed at the time of call of the trace event. The TP_printk() can
> happen any time later, when someone reads the tracing buffer.

Ok, thanks for pointing that out. I will fix for next set.