diff mbox series

[v4,04/16] PM / devfreq: tegra: Don't ignore clk errors

Message ID 20190501233815.32643-5-digetx@gmail.com (mailing list archive)
State Not Applicable, archived
Headers show
Series NVIDIA Tegra devfreq improvements and Tegra20/30 support | expand

Commit Message

Dmitry Osipenko May 1, 2019, 11:38 p.m. UTC 
The clk_set_min_rate() could fail and in this case clk_set_rate() sets
rate to 0, which may drop EMC rate to minimum and make machine very
difficult to use.

Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/devfreq/tegra-devfreq.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

Comments

Thierry Reding June 4, 2019, 10:57 a.m. UTC | #1 
On Thu, May 02, 2019 at 02:38:03AM +0300, Dmitry Osipenko wrote:
> The clk_set_min_rate() could fail and in this case clk_set_rate() sets
> rate to 0, which may drop EMC rate to minimum and make machine very
> difficult to use.
> 
> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---
>  drivers/devfreq/tegra-devfreq.c | 16 ++++++++++++++--
>  1 file changed, 14 insertions(+), 2 deletions(-)

Acked-by: Thierry Reding <treding@nvidia.com>
diff mbox series

Patch

diff --git a/drivers/devfreq/tegra-devfreq.c b/drivers/devfreq/tegra-devfreq.c
index 7d7b9a5895b2..c7428c5eee23 100644
--- a/drivers/devfreq/tegra-devfreq.c
+++ b/drivers/devfreq/tegra-devfreq.c
@@ -484,8 +484,10 @@  static int tegra_devfreq_target(struct device *dev, unsigned long *freq,
 				u32 flags)
 {
 	struct tegra_devfreq *tegra = dev_get_drvdata(dev);
+	struct devfreq *devfreq = tegra->devfreq;
 	struct dev_pm_opp *opp;
 	unsigned long rate;
+	int err;
 
 	opp = devfreq_recommended_opp(dev, freq, flags);
 	if (IS_ERR(opp)) {
@@ -495,10 +497,20 @@  static int tegra_devfreq_target(struct device *dev, unsigned long *freq,
 	rate = dev_pm_opp_get_freq(opp);
 	dev_pm_opp_put(opp);
 
-	clk_set_min_rate(tegra->emc_clock, rate);
-	clk_set_rate(tegra->emc_clock, 0);
+	err = clk_set_min_rate(tegra->emc_clock, rate);
+	if (err)
+		return err;
+
+	err = clk_set_rate(tegra->emc_clock, 0);
+	if (err)
+		goto restore_min_rate;
 
 	return 0;
+
+restore_min_rate:
+	clk_set_min_rate(tegra->emc_clock, devfreq->previous_freq);
+
+	return err;
 }
 
 static int tegra_devfreq_get_dev_status(struct device *dev,