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Message-Id: <36de122e568dcba371d3581e5f936243b405a874.1698661048.git.viresh.kumar@linaro.org>
Date: Mon, 30 Oct 2023 15:54:15 +0530
From: Viresh Kumar <viresh.kumar@...aro.org>
To: Viresh Kumar <vireshk@...nel.org>, Nishanth Menon <nm@...com>,
Stephen Boyd <sboyd@...nel.org>,
"Rafael J. Wysocki" <rafael@...nel.org>
Cc: Viresh Kumar <viresh.kumar@...aro.org>, linux-pm@...r.kernel.org,
Vincent Guittot <vincent.guittot@...aro.org>,
Ulf Hansson <ulf.hansson@...aro.org>,
Stephan Gerhold <stephan.gerhold@...nkonzept.com>,
Konrad Dybcio <konrad.dybcio@...aro.org>,
Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>,
linux-kernel@...r.kernel.org
Subject: [PATCH V2 1/3] OPP: Level zero is valid
The level zero can be used by some OPPs to drop performance state vote
for the device. It is perfectly fine to allow the same.
_set_opp_level() considers it as an invalid value currently and returns
early.
In order to support this properly, initialize the level field with
U32_MAX, which denotes unused level field.
Reported-by: Stephan Gerhold <stephan.gerhold@...nkonzept.com>
Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
---
drivers/opp/core.c | 24 ++++++++++++++++++++----
drivers/opp/of.c | 8 +++++++-
include/linux/pm_opp.h | 5 ++++-
3 files changed, 31 insertions(+), 6 deletions(-)
diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index 84f345c69ea5..f2e2aa07b431 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -201,7 +201,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_freq_indexed);
* @opp: opp for which level value has to be returned for
*
* Return: level read from device tree corresponding to the opp, else
- * return 0.
+ * return U32_MAX.
*/
unsigned int dev_pm_opp_get_level(struct dev_pm_opp *opp)
{
@@ -221,7 +221,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_level);
* @index: index of the required opp
*
* Return: performance state read from device tree corresponding to the
- * required opp, else return 0.
+ * required opp, else return U32_MAX.
*/
unsigned int dev_pm_opp_get_required_pstate(struct dev_pm_opp *opp,
unsigned int index)
@@ -808,6 +808,14 @@ struct dev_pm_opp *dev_pm_opp_find_level_ceil(struct device *dev,
struct dev_pm_opp *opp;
opp = _find_key_ceil(dev, &temp, 0, true, _read_level, NULL);
+
+ /* False match */
+ if (temp == OPP_LEVEL_UNSET) {
+ dev_err(dev, "%s: OPP levels aren't available\n", __func__);
+ dev_pm_opp_put(opp);
+ return ERR_PTR(-ENODEV);
+ }
+
*level = temp;
return opp;
}
@@ -1049,12 +1057,18 @@ static int _set_opp_bw(const struct opp_table *opp_table,
static int _set_performance_state(struct device *dev, struct device *pd_dev,
struct dev_pm_opp *opp, int i)
{
- unsigned int pstate = likely(opp) ? opp->required_opps[i]->level: 0;
+ unsigned int pstate = 0;
int ret;
if (!pd_dev)
return 0;
+ if (likely(opp)) {
+ pstate = opp->required_opps[i]->level;
+ if (pstate == OPP_LEVEL_UNSET)
+ return 0;
+ }
+
ret = dev_pm_domain_set_performance_state(pd_dev, pstate);
if (ret) {
dev_err(dev, "Failed to set performance state of %s: %d (%d)\n",
@@ -1135,7 +1149,7 @@ static int _set_opp_level(struct device *dev, struct opp_table *opp_table,
int ret = 0;
if (opp) {
- if (!opp->level)
+ if (opp->level == OPP_LEVEL_UNSET)
return 0;
level = opp->level;
@@ -1867,6 +1881,8 @@ struct dev_pm_opp *_opp_allocate(struct opp_table *opp_table)
INIT_LIST_HEAD(&opp->node);
+ opp->level = OPP_LEVEL_UNSET;
+
return opp;
}
diff --git a/drivers/opp/of.c b/drivers/opp/of.c
index 81fa27599d58..85fad7ca0007 100644
--- a/drivers/opp/of.c
+++ b/drivers/opp/of.c
@@ -1393,8 +1393,14 @@ int of_get_required_opp_performance_state(struct device_node *np, int index)
opp = _find_opp_of_np(opp_table, required_np);
if (opp) {
- pstate = opp->level;
+ if (opp->level == OPP_LEVEL_UNSET) {
+ pr_err("%s: OPP levels aren't available for %pOF\n",
+ __func__, np);
+ } else {
+ pstate = opp->level;
+ }
dev_pm_opp_put(opp);
+
}
dev_pm_opp_put_opp_table(opp_table);
diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h
index ccd97bcef269..af53101a1383 100644
--- a/include/linux/pm_opp.h
+++ b/include/linux/pm_opp.h
@@ -92,9 +92,12 @@ struct dev_pm_opp_config {
struct device ***virt_devs;
};
+#define OPP_LEVEL_UNSET U32_MAX
+
/**
* struct dev_pm_opp_data - The data to use to initialize an OPP.
- * @level: The performance level for the OPP.
+ * @level: The performance level for the OPP. Set level to OPP_LEVEL_UNSET if
+ * level field isn't used.
* @freq: The clock rate in Hz for the OPP.
* @u_volt: The voltage in uV for the OPP.
*/
--
2.31.1.272.g89b43f80a514
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