Re: [PATCH v4 1/7] OPP: Add support to find OPP for a set of keys

[Viresh Kumar <viresh.kumar@linaro.org>]

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@oss.qualcomm.com>
> ---
>  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