Support set_opp() customization without requiring to use regulators. This is needed by drivers which want to use dev_pm_opp_set_rate() for changing rates of a multiple clocks and don't need to touch regulator.
One example is NVIDIA Tegra30/114 SoCs which have two sibling 3D hardware units which should be use to the same clock rate, meanwhile voltage scaling is done using a power domain. In this case OPP table doesn't have a regulator, causing a NULL dereference in _set_opp_custom(). Tested-by: Peter Geis <[email protected]> Tested-by: Nicolas Chauvet <[email protected]> Tested-by: Matt Merhar <[email protected]> Signed-off-by: Dmitry Osipenko <[email protected]> --- drivers/opp/core.c | 46 +++++++++++++++++++++++++++++++++++------- include/linux/pm_opp.h | 3 +++ 2 files changed, 42 insertions(+), 7 deletions(-) diff --git a/drivers/opp/core.c b/drivers/opp/core.c index 49419ab9fbb4..7726c4c40b53 100644 --- a/drivers/opp/core.c +++ b/drivers/opp/core.c @@ -829,16 +829,21 @@ static int _set_opp_custom(const struct opp_table *opp_table, struct dev_pm_opp_supply *new_supply) { struct dev_pm_set_opp_data *data; - int size; + int size, count; + + if (opp_table->regulators) + count = opp_table->regulator_count; + else + count = 0; data = opp_table->set_opp_data; data->regulators = opp_table->regulators; - data->regulator_count = opp_table->regulator_count; + data->regulator_count = count; data->clk = opp_table->clk; data->dev = dev; data->old_opp.rate = old_freq; - size = sizeof(*old_supply) * opp_table->regulator_count; + size = sizeof(*old_supply) * count; if (!old_supply) memset(data->old_opp.supplies, 0, size); else @@ -1860,8 +1865,14 @@ static int _allocate_set_opp_data(struct opp_table *opp_table) struct dev_pm_set_opp_data *data; int len, count = opp_table->regulator_count; - if (WARN_ON(!opp_table->regulators)) - return -EINVAL; + /* just bump the refcount if already allocated */ + if (opp_table->set_opp_data) { + kref_get(&opp_table->set_opp_data->kref); + return 0; + } + + /* allocate maximum number of regulators, for simplicity */ + count = max(count, 1); /* space for set_opp_data */ len = sizeof(*data); @@ -1873,6 +1884,7 @@ static int _allocate_set_opp_data(struct opp_table *opp_table) if (!data) return -ENOMEM; + kref_init(&data->kref); data->old_opp.supplies = (void *)(data + 1); data->new_opp.supplies = data->old_opp.supplies + count; @@ -1881,10 +1893,17 @@ static int _allocate_set_opp_data(struct opp_table *opp_table) return 0; } +static void _release_set_opp_data(struct kref *kref) +{ + kfree(container_of(kref, struct dev_pm_set_opp_data, kref)); +} + static void _free_set_opp_data(struct opp_table *opp_table) { - kfree(opp_table->set_opp_data); - opp_table->set_opp_data = NULL; + struct dev_pm_set_opp_data *data = opp_table->set_opp_data; + + if (kref_put(&data->kref, _release_set_opp_data)) + opp_table->set_opp_data = NULL; } /** @@ -2182,6 +2201,7 @@ struct opp_table *dev_pm_opp_register_set_opp_helper(struct device *dev, int (*set_opp)(struct dev_pm_set_opp_data *data)) { struct opp_table *opp_table; + int ret; if (!set_opp) return ERR_PTR(-EINVAL); @@ -2196,11 +2216,21 @@ struct opp_table *dev_pm_opp_register_set_opp_helper(struct device *dev, return ERR_PTR(-EBUSY); } + /* Allocate block to pass to set_opp() routines */ + ret = _allocate_set_opp_data(opp_table); + if (ret) + goto err; + /* Another CPU that shares the OPP table has set the helper ? */ if (!opp_table->set_opp) opp_table->set_opp = set_opp; return opp_table; + +err: + dev_pm_opp_put_opp_table(opp_table); + + return ERR_PTR(ret); } EXPORT_SYMBOL_GPL(dev_pm_opp_register_set_opp_helper); @@ -2219,6 +2249,8 @@ void dev_pm_opp_unregister_set_opp_helper(struct opp_table *opp_table) /* Make sure there are no concurrent readers while updating opp_table */ WARN_ON(!list_empty(&opp_table->opp_list)); + _free_set_opp_data(opp_table); + opp_table->set_opp = NULL; dev_pm_opp_put_opp_table(opp_table); } diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h index eefd0b15890c..c98fd2add563 100644 --- a/include/linux/pm_opp.h +++ b/include/linux/pm_opp.h @@ -13,6 +13,7 @@ #include <linux/energy_model.h> #include <linux/err.h> +#include <linux/kref.h> #include <linux/notifier.h> struct clk; @@ -74,6 +75,7 @@ struct dev_pm_opp_info { * @regulator_count: Number of regulators * @clk: Pointer to clk * @dev: Pointer to the struct device + * @kref: Reference counter * * This structure contains all information required for setting an OPP. */ @@ -85,6 +87,7 @@ struct dev_pm_set_opp_data { unsigned int regulator_count; struct clk *clk; struct device *dev; + struct kref kref; }; #if defined(CONFIG_PM_OPP) -- 2.29.2
