On 22/11/2018 08:55, Jon Hunter wrote:

On 21/11/2018 16:13, Ben Dooks wrote:

quoted

Add some trace-points to the driver to allow for debuging via the
trace pipe.

Signed-off-by: Ben Dooks <redacted>
---
Fixes since v1:
- take copy of dmachan name instead of pointer to device

Fixes since v2:
- finish off Steven's review comments
- fix saving the dma channel name
- use txstate as argument to trace_tegra_dma_tx_status()
- fix type of dma_cookie to dma_cookie_t

Cc: Ingo Molnar <mingo@redhat.com> (maintainer:TRACING)
Cc: Steven Rostedt <rostedt@goodmis.org> (maintainer:TRACING)
---
  drivers/dma/tegra20-apb-dma.c        |  7 ++++
  include/trace/events/tegra_apb_dma.h | 61 ++++++++++++++++++++++++++++
  2 files changed, 68 insertions(+)
  create mode 100644 include/trace/events/tegra_apb_dma.h

diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
index c60c3f7cad5f..659b49bf6fdb 100644
--- a/drivers/dma/tegra20-apb-dma.c
+++ b/drivers/dma/tegra20-apb-dma.c

@@ -38,6 +38,9 @@
  
  #include "dmaengine.h"
  
+#define CREATE_TRACE_POINTS
+#include <trace/events/tegra_apb_dma.h>
+
  #define TEGRA_APBDMA_GENERAL			0x0
  #define TEGRA_APBDMA_GENERAL_ENABLE		BIT(31)
  

@@ -672,6 +675,8 @@ static void tegra_dma_tasklet(unsigned long data)
  		dmaengine_desc_get_callback(&dma_desc->txd, &cb);
  		cb_count = dma_desc->cb_count;
  		dma_desc->cb_count = 0;
+		trace_tegra_dma_complete_cb(&tdc->dma_chan, cb_count,
+					    cb.callback);
  		spin_unlock_irqrestore(&tdc->lock, flags);
  		while (cb_count--)
  			dmaengine_desc_callback_invoke(&cb, NULL);

@@ -688,6 +693,7 @@ static irqreturn_t tegra_dma_isr(int irq, void *dev_id)
  
  	spin_lock_irqsave(&tdc->lock, flags);
  
+	trace_tegra_dma_isr(&tdc->dma_chan, irq);
  	status = tdc_read(tdc, TEGRA_APBDMA_CHAN_STATUS);
  	if (status & TEGRA_APBDMA_STATUS_ISE_EOC) {
  		tdc_write(tdc, TEGRA_APBDMA_CHAN_STATUS, status);

@@ -846,6 +852,7 @@ static enum dma_status tegra_dma_tx_status(struct dma_chan *dc,
  		dma_set_residue(txstate, residual);
  	}
  
+	trace_tegra_dma_tx_status(&tdc->dma_chan, cookie, txstate);
  	spin_unlock_irqrestore(&tdc->lock, flags);
  	return ret;
  }

My only comment here is that apart from the ISR trace, the others could
be added to the dmaengine driver core and then these could be used for
other DMAs as well.

Hmm, I will go have a look at how difficult that would be.