Re: [PATCH v4 1/7] OPP: Add support to find OPP for a set of keys
From: Viresh Kumar
Date: Fri Aug 22 2025 - 02:51:59 EST
On 20-08-25, 13:58, Krishna Chaitanya Chundru wrote:
> Some clients, such as PCIe, may operate at the same clock frequency
> across different data rates by varying link width. In such cases,
> frequency alone is not sufficient to uniquely identify an OPP.
> To support these scenarios, introduce a new API
> dev_pm_opp_find_key_exact() that allows OPP lookup with different
> set of keys like freq, level & bandwidth.
>
> Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@xxxxxxxxxxxxxxxx>
> ---
> drivers/opp/core.c | 97 ++++++++++++++++++++++++++++++++++++++++++++++++++
> include/linux/pm_opp.h | 30 ++++++++++++++++
> 2 files changed, 127 insertions(+)
Applied with this diff:
diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index a36c3daac39c..bba4f7daff8c 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -476,7 +476,8 @@ static unsigned long _read_bw(struct dev_pm_opp *opp, int index)
return opp->bandwidth[index].peak;
}
-static unsigned long _read_opp_key(struct dev_pm_opp *opp, int index, struct dev_pm_opp_key *key)
+static unsigned long _read_opp_key(struct dev_pm_opp *opp, int index,
+ struct dev_pm_opp_key *key)
{
key->bw = opp->bandwidth ? opp->bandwidth[index].peak : 0;
key->freq = opp->rates[index];
@@ -518,12 +519,13 @@ static bool _compare_floor(struct dev_pm_opp **opp, struct dev_pm_opp *temp_opp,
return false;
}
-static bool _compare_opp_key_exact(struct dev_pm_opp **opp, struct dev_pm_opp *temp_opp,
- struct dev_pm_opp_key opp_key, struct dev_pm_opp_key key)
+static bool _compare_opp_key_exact(struct dev_pm_opp **opp,
+ struct dev_pm_opp *temp_opp, struct dev_pm_opp_key *opp_key,
+ struct dev_pm_opp_key *key)
{
- bool level_match = (key.level == OPP_LEVEL_UNSET || opp_key.level == key.level);
- bool freq_match = (key.freq == 0 || opp_key.freq == key.freq);
- bool bw_match = (key.bw == 0 || opp_key.bw == key.bw);
+ bool level_match = (key->level == OPP_LEVEL_UNSET || opp_key->level == key->level);
+ bool freq_match = (key->freq == 0 || opp_key->freq == key->freq);
+ bool bw_match = (key->bw == 0 || opp_key->bw == key->bw);
if (freq_match && level_match && bw_match) {
*opp = temp_opp;
@@ -570,7 +572,7 @@ static struct dev_pm_opp *_opp_table_find_opp_key(struct opp_table *opp_table,
unsigned long (*read)(struct dev_pm_opp *opp, int index,
struct dev_pm_opp_key *key),
bool (*compare)(struct dev_pm_opp **opp, struct dev_pm_opp *temp_opp,
- struct dev_pm_opp_key opp_key, struct dev_pm_opp_key key),
+ struct dev_pm_opp_key *opp_key, struct dev_pm_opp_key *key),
bool (*assert)(struct opp_table *opp_table, unsigned int index))
{
struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
@@ -585,9 +587,8 @@ static struct dev_pm_opp *_opp_table_find_opp_key(struct opp_table *opp_table,
list_for_each_entry(temp_opp, &opp_table->opp_list, node) {
if (temp_opp->available == available) {
read(temp_opp, 0, &temp_key);
- if (compare(&opp, temp_opp, temp_key, *key)) {
+ if (compare(&opp, temp_opp, &temp_key, key)) {
/* Increment the reference count of OPP */
- *key = temp_key;
dev_pm_opp_get(opp);
break;
}
@@ -689,20 +690,20 @@ struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev,
EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_exact);
/**
- * dev_pm_opp_find_key_exact() - Search for an exact OPP key
- * @dev: Device for which the OPP is being searched
- * @key: OPP key to match
- * @available: true/false - match for available OPP
+ * dev_pm_opp_find_key_exact() - Search for an OPP with exact key set
+ * @dev: Device for which the OPP is being searched
+ * @key: OPP key set to match
+ * @available: true/false - match for available OPP
*
- * Search for an exact match the OPP key in the OPP table.
+ * Search for an exact match of the key set in the OPP table.
*
- * Return: matching *opp, else returns ERR_PTR in case of error and should
- * be using IS_ERR. Error return values can be:
- * EINVAL: for bad pointer
- * ERANGE: no match found for search
- * ENODEV: if device not found in list of registered devices
+ * Return: A matching opp on success, else ERR_PTR in case of error.
+ * Possible error values:
+ * EINVAL: for bad pointers
+ * ERANGE: no match found for search
+ * ENODEV: if device not found in list of registered devices
*
- * Note: 'available' is a modifier for the search. If 'available'=true,
+ * Note: 'available' is a modifier for the search. If 'available' == true,
* then the match is for exact matching key and is available in the stored
* OPP table. If false, the match is for exact key which is not available.
*
@@ -713,7 +714,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_exact);
* use.
*/
struct dev_pm_opp *dev_pm_opp_find_key_exact(struct device *dev,
- struct dev_pm_opp_key key,
+ struct dev_pm_opp_key *key,
bool available)
{
struct opp_table *opp_table __free(put_opp_table) = _find_opp_table(dev);
@@ -724,8 +725,9 @@ struct dev_pm_opp *dev_pm_opp_find_key_exact(struct device *dev,
return ERR_CAST(opp_table);
}
- return _opp_table_find_opp_key(opp_table, &key, available, _read_opp_key,
- _compare_opp_key_exact, assert_single_clk);
+ return _opp_table_find_opp_key(opp_table, key, available,
+ _read_opp_key, _compare_opp_key_exact,
+ assert_single_clk);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_find_key_exact);
diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h
index 5d244bf97489..789406d95e69 100644
--- a/include/linux/pm_opp.h
+++ b/include/linux/pm_opp.h
@@ -151,7 +151,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev,
bool available);
struct dev_pm_opp *dev_pm_opp_find_key_exact(struct device *dev,
- struct dev_pm_opp_key key,
+ struct dev_pm_opp_key *key,
bool available);
struct dev_pm_opp *
@@ -313,7 +313,7 @@ static inline struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev,
}
static inline struct dev_pm_opp *dev_pm_opp_find_key_exact(struct device *dev,
- struct dev_pm_opp_key key,
+ struct dev_pm_opp_key *key,
bool available)
{
return ERR_PTR(-EOPNOTSUPP);
--
viresh