On Fri, 12 Oct 2018 10:44:54 +0100
Ben Dooks <ben.dooks@xxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxx>
> ---
> Cc: Ingo Molnar <mingo@xxxxxxxxxx> (maintainer:TRACING)
> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx> (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.
-- Steve
> + __entry->ahb, __entry->wc, __entry->done,
> + __entry->byte_count, __entry->residual)
> +);
> +
> TRACE_EVENT(tegra_dma_isr,
> TP_PROTO(struct dma_chan *dc, int irq),
> TP_ARGS(dc, irq),
