On Wed, 31 Oct 2018 16:03:08 +0000
Ben Dooks <ben.dooks@xxxxxxxxxxxxxxx> wrote:
> diff --git a/include/trace/events/tegra_apb_dma.h b/include/trace/events/tegra_apb_dma.h
> new file mode 100644
> index 000000000000..1f55c2c6049d
> --- /dev/null
> +++ b/include/trace/events/tegra_apb_dma.h
> @@ -0,0 +1,61 @@
> +#if !defined(_TRACE_TEGRA_APB_DMA_H) || defined(TRACE_HEADER_MULTI_READ)
> +#define _TRACE_TEGRA_APM_DMA_H
> +
> +#include <linux/tracepoint.h>
> +#include <linux/dmaengine.h>
> +
> +#undef TRACE_SYSTEM
> +#define TRACE_SYSTEM tegra_apb_dma
> +
> +TRACE_EVENT(tegra_dma_tx_status,
> + TP_PROTO(struct dma_chan *dc, s32 cookie, u32 residue),
> + TP_ARGS(dc, cookie, residue),
> + TP_STRUCT__entry(
> + __string(chan, 16)
Hi Ben,
Was this tested? Because I think __string(chan, 16) would fault, as the
second parameter is meant to be a pointer to the source parameter.
Otherwise, you need to add dev_name(&dc->dev->device) as the second
parameter.
If you are just using fixed string lengths then it's best not to use the
__string() type, as that's for dynamic strings (strings changing in
size for each event) and uses 8 more bytes to store the offset and
length of the string in the event.
If you take a look at the sched_waking or sched_switch trace events in
include/trace/events/sched.h you'll see that it saves the comm string
directly as a character array:
__array( char, comm, TASK_COMM_LEN)
For you, you can use:
__array(char, chan, 16)
> + __field(__s32, cookie)
> + __field(__u32, residue)
> + ),
> + TP_fast_assign(
> + __assign_str(chan, dev_name(&dc->dev->device));
Then to store the array:
memcpy(__entry->chan, dev_name(&dc->dev->device), 16);
> + __entry->cookie = cookie;
> + __entry->residue = residue;
> + ),
> + TP_printk("channel %s: dma cookie %d, residue %u",
__entry->chan,
is all that's needed.
Same for the other references to chan.
Unless you meant to store each with a different size, then you need to
replace that "16" with the dev_name(&dc->dev->device).
-- Steve
> + __get_str(chan), __entry->cookie, __entry->residue)
> +);
> +
> +TRACE_EVENT(tegra_dma_complete_cb,
> + TP_PROTO(struct dma_chan *dc, int count, void *ptr),
> + TP_ARGS(dc, count, ptr),
> + TP_STRUCT__entry(
> + __string(chan, 16)
> + __field(int, count)
> + __field(void *, ptr)
> + ),
> + TP_fast_assign(
> + __assign_str(chan, dev_name(&dc->dev->device));
> + __entry->count = count;
> + __entry->ptr = ptr;
> + ),
> + TP_printk("channel %s: done %d, ptr %p",
> + __get_str(chan), __entry->count, __entry->ptr)
> +);
> +
> +TRACE_EVENT(tegra_dma_isr,
> + TP_PROTO(struct dma_chan *dc, int irq),
> + TP_ARGS(dc, irq),
> + TP_STRUCT__entry(
> + __string(chan, 16)
> + __field(int, irq)
> + ),
> + TP_fast_assign(
> + __assign_str(chan, dev_name(&dc->dev->device));
> + __entry->irq = irq;
> + ),
> + TP_printk("%s: irq %d\n", __get_str(chan), __entry->irq)
> +);
> +
> +#endif /* _TRACE_TEGRADMA_H */
> +
> +/* This part must be outside protection */
> +#include <trace/define_trace.h>
