coresight: etm3x: unlocking tracers in default arch init

Calling function 'smp_call_function_single()' to unlock a
tracer and calling it again right after to perform the
default initialisation doesn't make sense.

Moving 'etm_os_unlock()' just before making the default
initialisation results in the same outcome while saving
one call to 'smp_call_function_single()'.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit ae69a1da399fccaed406932f5cbee55a6f9d4425)

diff --git a/drivers/hwtracing/coresight/coresight-etm3x.c b/drivers/hwtracing/coresight/coresight-etm3x.c
index 6ea35b35095858d555c5db686222ddfe5eff4147..f2c74bb56993da386d6941d5bd51898b12beed28 100644 (file)
--- a/drivers/hwtracing/coresight/coresight-etm3x.c
+++ b/drivers/hwtracing/coresight/coresight-etm3x.c
@@ -47,11 +47,11 @@ static struct etm_drvdata *etmdrvdata[NR_CPUS];
  * and OS lock must be unlocked before any memory mapped access on such
  * processors, otherwise memory mapped reads/writes will be invalid.
  */
-static void etm_os_unlock(void *info)
+static void etm_os_unlock(struct etm_drvdata *drvdata)
 {
-       struct etm_drvdata *drvdata = (struct etm_drvdata *)info;
        /* Writing any value to ETMOSLAR unlocks the trace registers */
        etm_writel(drvdata, 0x0, ETMOSLAR);
+       drvdata->os_unlock = true;
        isb();
 }
 
@@ -483,6 +483,9 @@ static void etm_init_arch_data(void *info)
        u32 etmccr;
        struct etm_drvdata *drvdata = info;
 
+       /* Make sure all registers are accessible */
+       etm_os_unlock(drvdata);
+
        CS_UNLOCK(drvdata->base);
 
        /* First dummy read */
@@ -607,9 +610,6 @@ static int etm_probe(struct amba_device *adev, const struct amba_id *id)
        get_online_cpus();
        etmdrvdata[drvdata->cpu] = drvdata;
 
-       if (!smp_call_function_single(drvdata->cpu, etm_os_unlock, drvdata, 1))
-               drvdata->os_unlock = true;
-
        if (smp_call_function_single(drvdata->cpu,
                                     etm_init_arch_data,  drvdata, 1))
                dev_err(dev, "ETM arch init failed\n");