[PATCH 4/8] OPP: Make dev_pm_opp_set_opp() independent of frequency

Viresh Kumar
2022-06-10T08:24:51Z

dev_pm_opp_set_opp() can be called for any device, it may or may not
have a frequency value associated with it.

If a frequency value isn't available, we pass 0 to _set_opp(). Make it
optional instead by making _set_opp() accept a pointer instead, as the
frequency value is anyway available in the OPP. This makes
dev_pm_opp_set_opp() and _set_opp() completely independent of any
special key value.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
drivers/opp/core.c | 52 +++++++++++++++++++++++++++++++++-------------
drivers/opp/opp.h | 4 ++--
2 files changed, 40 insertions(+), 16 deletions(-)

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index 9f284dc0d9d7..6368ae2d7360 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -766,19 +766,33 @@ static int _set_opp_voltage(struct device *dev, struct regulator *reg,
return ret;
}

-static inline int _generic_set_opp_clk_only(struct device *dev, struct clk *clk,
- unsigned long freq)
+static inline int _generic_set_opp_clk_only(struct device *dev,
+ struct opp_table *opp_table, struct dev_pm_opp *opp, void *data)
{
+ unsigned long *target = data;
+ unsigned long freq;
int ret;

/* We may reach here for devices which don't change frequency */
- if (IS_ERR(clk))
+ if (IS_ERR(opp_table->clk))
return 0;

- ret = clk_set_rate(clk, freq);
+ /* One of target and opp must be available */
+ if (target) {
+ freq = *target;
+ } else if (opp) {
+ freq = opp->rate;
+ } else {
+ WARN_ON(1);
+ return -EINVAL;
+ }
+
+ ret = clk_set_rate(opp_table->clk, freq);
if (ret) {
dev_err(dev, "%s: failed to set clock rate: %d\n", __func__,
ret);
+ } else {
+ opp_table->rate_clk_single = freq;
}

return ret;
@@ -972,7 +986,7 @@ static int _disable_opp_table(struct device *dev, struct opp_table *opp_table)
}

static int _set_opp(struct device *dev, struct opp_table *opp_table,
- struct dev_pm_opp *opp, unsigned long freq)
+ struct dev_pm_opp *opp, void *clk_data, bool forced)
{
struct dev_pm_opp *old_opp;
int scaling_down, ret;
@@ -987,15 +1001,14 @@ static int _set_opp(struct device *dev, struct opp_table *opp_table,
old_opp = opp_table->current_opp;

/* Return early if nothing to do */
- if (old_opp == opp && opp_table->current_rate == freq &&
- opp_table->enabled) {
+ if (!forced && old_opp == opp && opp_table->enabled) {
dev_dbg(dev, "%s: OPPs are same, nothing to do\n", __func__);
return 0;
}

dev_dbg(dev, "%s: switching OPP: Freq %lu -> %lu Hz, Level %u -> %u, Bw %u -> %u\n",
- __func__, opp_table->current_rate, freq, old_opp->level,
- opp->level, old_opp->bandwidth ? old_opp->bandwidth[0].peak : 0,
+ __func__, old_opp->rate, opp->rate, old_opp->level, opp->level,
+ old_opp->bandwidth ? old_opp->bandwidth[0].peak : 0,
opp->bandwidth ? opp->bandwidth[0].peak : 0);

scaling_down = _opp_compare_key(old_opp, opp);
@@ -1028,7 +1041,7 @@ static int _set_opp(struct device *dev, struct opp_table *opp_table,
}
}

- ret = _generic_set_opp_clk_only(dev, opp_table->clk, freq);
+ ret = _generic_set_opp_clk_only(dev, opp_table, opp, clk_data);
if (ret)
return ret;

@@ -1064,7 +1077,6 @@ static int _set_opp(struct device *dev, struct opp_table *opp_table,
/* Make sure current_opp doesn't get freed */
dev_pm_opp_get(opp);
opp_table->current_opp = opp;
- opp_table->current_rate = freq;

return ret;
}
@@ -1085,6 +1097,7 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
struct opp_table *opp_table;
unsigned long freq = 0, temp_freq;
struct dev_pm_opp *opp = NULL;
+ bool forced = false;
int ret;

opp_table = _find_opp_table(dev);
@@ -1102,7 +1115,8 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
* equivalent to a clk_set_rate()
*/
if (!_get_opp_count(opp_table)) {
- ret = _generic_set_opp_clk_only(dev, opp_table->clk, target_freq);
+ ret = _generic_set_opp_clk_only(dev, opp_table, NULL,
+ &target_freq);
goto put_opp_table;
}

@@ -1123,12 +1137,22 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
__func__, freq, ret);
goto put_opp_table;
}
+
+ /*
+ * An OPP entry specifies the highest frequency at which other
+ * properties of the OPP entry apply. Even if the new OPP is
+ * same as the old one, we may still reach here for a different
+ * value of the frequency. In such a case, do not abort but
+ * configure the hardware to the desired frequency forcefully.
+ */
+ forced = opp_table->rate_clk_single != target_freq;
}

- ret = _set_opp(dev, opp_table, opp, freq);
+ ret = _set_opp(dev, opp_table, opp, &target_freq, forced);

if (target_freq)
dev_pm_opp_put(opp);
+
put_opp_table:
dev_pm_opp_put_opp_table(opp_table);
return ret;
@@ -1156,7 +1180,7 @@ int dev_pm_opp_set_opp(struct device *dev, struct dev_pm_opp *opp)
return PTR_ERR(opp_table);
}

- ret = _set_opp(dev, opp_table, opp, opp ? opp->rate : 0);
+ ret = _set_opp(dev, opp_table, opp, NULL, false);
dev_pm_opp_put_opp_table(opp_table);

return ret;
diff --git a/drivers/opp/opp.h b/drivers/opp/opp.h
index 4d8894ef2975..131fc7c05db8 100644
--- a/drivers/opp/opp.h
+++ b/drivers/opp/opp.h
@@ -138,7 +138,7 @@ enum opp_table_access {
* @clock_latency_ns_max: Max clock latency in nanoseconds.
* @parsed_static_opps: Count of devices for which OPPs are initialized from DT.
* @shared_opp: OPP is shared between multiple devices.
- * @current_rate: Currently configured frequency.
+ * @rate_clk_single: Currently configured frequency for single clk.
* @current_opp: Currently configured OPP for the table.
* @suspend_opp: Pointer to OPP to be used during device suspend.
* @genpd_virt_dev_lock: Mutex protecting the genpd virtual device pointers.
@@ -187,7 +187,7 @@ struct opp_table {

unsigned int parsed_static_opps;
enum opp_table_access shared_opp;
- unsigned long current_rate;
+ unsigned long rate_clk_single;
struct dev_pm_opp *current_opp;
struct dev_pm_opp *suspend_opp;

--
2.31.1.272.g89b43f80a514