[PATCH v16 01/40] soc/tegra: Enable runtime PM during OPP state-syncing

Dmitry Osipenko
2021-11-30T23:24:07Z

GENPD core now can set up domain's performance state properly while device
is RPM-suspended. Runtime PM of a device must be enabled during setup
because GENPD checks whether device is suspended and check doesn't work
while RPM is disabled. Instead of replicating the boilerplate RPM-enable
code around OPP helper for each driver, let's make OPP helper to take care
of enabling it.

Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
drivers/soc/tegra/common.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)

diff --git a/drivers/soc/tegra/common.c b/drivers/soc/tegra/common.c
index cd33e99249c3..35c882da55fc 100644
--- a/drivers/soc/tegra/common.c
+++ b/drivers/soc/tegra/common.c
@@ -10,6 +10,7 @@
#include <linux/export.h>
#include <linux/of.h>
#include <linux/pm_opp.h>
+#include <linux/pm_runtime.h>

#include <soc/tegra/common.h>
#include <soc/tegra/fuse.h>
@@ -43,6 +44,7 @@ static int tegra_core_dev_init_opp_state(struct device *dev)
{
unsigned long rate;
struct clk *clk;
+ bool rpm_enabled;
int err;

clk = devm_clk_get(dev, NULL);
@@ -57,8 +59,31 @@ static int tegra_core_dev_init_opp_state(struct device *dev)
return -EINVAL;
}

+ /*
+ * Runtime PM of the device must be enabled in order to set up
+ * GENPD's performance properly because GENPD core checks whether
+ * device is suspended and this check doesn't work while RPM is
+ * disabled. This makes sure the OPP vote below gets cached in
+ * GENPD for the device. Instead, the vote is done the next time
+ * the device gets runtime resumed.
+ */
+ rpm_enabled = pm_runtime_enabled(dev);
+ if (!rpm_enabled)
+ pm_runtime_enable(dev);
+
+ /* should never happen in practice */
+ if (!pm_runtime_enabled(dev)) {
+ dev_WARN(dev, "failed to enable runtime PM\n");
+ pm_runtime_disable(dev);
+ return -EINVAL;
+ }
+
/* first dummy rate-setting initializes voltage vote */
err = dev_pm_opp_set_rate(dev, rate);
+
+ if (!rpm_enabled)
+ pm_runtime_disable(dev);
+
if (err) {
dev_err(dev, "failed to initialize OPP clock: %d\n", err);
return err;
--
2.33.1