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: Arve Hjønnevåg <arve@android.com>
diff --git a/arch/arm/kernel/etm.c b/arch/arm/kernel/etm.c
index 3d21cf6..74444e5 100644
--- a/arch/arm/kernel/etm.c
+++ b/arch/arm/kernel/etm.c
@@ -45,6 +45,7 @@
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 @@
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 @@
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 @@
goto out_release;
}
+ t->dump_initial_etb = true;
amba_set_drvdata(dev, t);
etb_unlock(t);