[PATCH 10/15] ARM: etm: Wait for etm/ptm(s) to stop before requesting PowerDown

John Stultz
2012-06-20T22:50:07Z

From: Arve Hjønnevåg <arve@android.com>

When PowerDown was requested at the same time as ProgBit, the
formatter flush command that follows could get stuck.

CC: Russell King <linux@arm.linux.org.uk>
CC: Paul Gortmaker <paul.gortmaker@windriver.com>
CC: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Acked-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
arch/arm/kernel/etm.c | 36 ++++++++++++++++++++++++++++--------
1 file changed, 28 insertions(+), 8 deletions(-)

diff --git a/arch/arm/kernel/etm.c b/arch/arm/kernel/etm.c
index 66bf592..bad28de 100644
--- a/arch/arm/kernel/etm.c
+++ b/arch/arm/kernel/etm.c
@@ -200,11 +200,13 @@ static int trace_stop_etm(struct tracectx *t, int id)

etm_unlock(t, id);

- etm_writel(t, id, 0x441, ETMR_CTRL);
+ etm_writel(t, id, 0x440, ETMR_CTRL);
while (!(etm_readl(t, id, ETMR_CTRL) & ETMCTRL_PROGRAM) && --timeout)
;
if (!timeout) {
- dev_dbg(t->dev, "Waiting for progbit to assert timed out\n");
+ dev_err(t->dev,
+ "etm%d: Waiting for progbit to assert timed out\n",
+ id);
etm_lock(t, id);
return -EFAULT;
}
@@ -213,18 +215,36 @@ static int trace_stop_etm(struct tracectx *t, int id)
return 0;
}

+static int trace_power_down_etm(struct tracectx *t, int id)
+{
+ unsigned long timeout = TRACER_TIMEOUT;
+ etm_unlock(t, id);
+ while (!(etm_readl(t, id, ETMR_STATUS) & ETMST_PROGBIT) && --timeout)
+ ;
+ if (!timeout) {
+ dev_err(t->dev, "etm%d: Waiting for status progbit to assert timed out\n",
+ id);
+ etm_lock(t, id);
+ return -EFAULT;
+ }
+
+ etm_writel(t, id, 0x441, ETMR_CTRL);
+
+ etm_lock(t, id);
+ return 0;
+}
+
static int trace_stop(struct tracectx *t)
{
int id;
- int ret;
unsigned long timeout = TRACER_TIMEOUT;
u32 etb_fc = t->etb_fc;

- for (id = 0; id < t->etm_regs_count; id++) {
- ret = trace_stop_etm(t, id);
- if (ret)
- return ret;
- }
+ for (id = 0; id < t->etm_regs_count; id++)
+ trace_stop_etm(t, id);
+
+ for (id = 0; id < t->etm_regs_count; id++)
+ trace_power_down_etm(t, id);

etb_unlock(t);
if (etb_fc) {
--
1.7.9.5