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Commit 385e0061 authored by Arve Hjønnevåg's avatar Arve Hjønnevåg Committed by Ruchi Kandoi
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ARM: etm: Return the entire trace buffer if it is empty after reset 



On some SOCs the read and write pointer are reset when the chip
resets, but the trace buffer content is preserved. If the status
bits indicates that the buffer is empty and we have never started
tracing, assume the buffer is full instead. This can be useful
if the system rebooted from a watchdog reset.

Change-Id: Iaf21c2c329c6059004ee1d38e3dfff66d7d28029
Signed-off-by: default avatarArve Hjønnevåg <arve@android.com>
parent 3994a5c1

arch/arm/kernel/etm.c

+5 −0
Original line number Diff line number Diff line
@@ -45,6 +45,7 @@ struct tracectx { 
	unsigned long	range_end;

	unsigned long	data_range_start;

	unsigned long	data_range_end;

	bool		dump_initial_etb;

	struct device	*dev;

	struct clk	*emu_clk;

	struct mutex	mutex;
@@ -106,6 +107,7 @@ static int trace_start(struct tracectx *t) 


	etb_unlock(t);



	t->dump_initial_etb = false;

	etb_writel(t, 0, ETBR_WRITEADDR);

	etb_writel(t, 0, ETBR_FORMATTERCTRL);

	etb_writel(t, 1, ETBR_CTRL);
@@ -312,6 +314,8 @@ static ssize_t etb_read(struct file *file, char __user *data, 
	etb_unlock(t);



	total = etb_getdatalen(t);

	if (total == 0 && t->dump_initial_etb)

		total = t->etb_bufsz;

	if (total == t->etb_bufsz)

		first = etb_readl(t, ETBR_WRITEADDR);
@@ -386,6 +390,7 @@ static int etb_probe(struct amba_device *dev, const struct amba_id *id) 
		goto out_release;

	}



	t->dump_initial_etb = true;

	amba_set_drvdata(dev, t);



	etb_unlock(t);