Allow drivers to register DPLL pins without manually specifying a pin index.
Currently, drivers must provide a unique pin index when calling dpll_pin_get(). This works well for hardware-mapped pins but creates friction for drivers handling virtual pins or those without a strict hardware indexing scheme. Introduce DPLL_PIN_IDX_UNSPEC (U32_MAX). When a driver passes this value as the pin index: 1. The core allocates a unique index using an IDA 2. The allocated index is mapped to a range starting above `INT_MAX` This separation ensures that dynamically allocated indices never collide with standard driver-provided hardware indices, which are assumed to be within the `0` to `INT_MAX` range. The index is automatically freed when the pin is released in dpll_pin_put(). Signed-off-by: Ivan Vecera <[email protected]> --- drivers/dpll/dpll_core.c | 48 ++++++++++++++++++++++++++++++++++++++-- include/linux/dpll.h | 2 ++ 2 files changed, 48 insertions(+), 2 deletions(-) diff --git a/drivers/dpll/dpll_core.c b/drivers/dpll/dpll_core.c index 52f2ed888e46c..15a944553546f 100644 --- a/drivers/dpll/dpll_core.c +++ b/drivers/dpll/dpll_core.c @@ -10,6 +10,7 @@ #include <linux/device.h> #include <linux/err.h> +#include <linux/idr.h> #include <linux/property.h> #include <linux/slab.h> #include <linux/string.h> @@ -24,6 +25,7 @@ DEFINE_XARRAY_FLAGS(dpll_device_xa, XA_FLAGS_ALLOC); DEFINE_XARRAY_FLAGS(dpll_pin_xa, XA_FLAGS_ALLOC); static RAW_NOTIFIER_HEAD(dpll_notifier_chain); +static DEFINE_IDA(dpll_pin_idx_ida); static u32 dpll_device_xa_id; static u32 dpll_pin_xa_id; @@ -468,6 +470,36 @@ void dpll_device_unregister(struct dpll_device *dpll, } EXPORT_SYMBOL_GPL(dpll_device_unregister); +static int dpll_pin_idx_alloc(u32 *pin_idx) +{ + int ret; + + if (!pin_idx) + return -EINVAL; + + /* Alloc unique number from IDA. Number belongs to <0, INT_MAX> range */ + ret = ida_alloc(&dpll_pin_idx_ida, GFP_KERNEL); + if (ret < 0) + return ret; + + /* Map the value to dynamic pin index range <INT_MAX+1, U32_MAX> */ + *pin_idx = (u32)ret + INT_MAX + 1; + + return 0; +} + +static void dpll_pin_idx_free(u32 pin_idx) +{ + if (pin_idx <= INT_MAX) + return; /* Not a dynamic pin index */ + + /* Map the index value from dynamic pin index range to IDA range and + * free it. + */ + pin_idx -= INT_MAX - 1; + ida_free(&dpll_pin_idx_ida, pin_idx); +} + static void dpll_pin_prop_free(struct dpll_pin_properties *prop) { kfree(prop->package_label); @@ -525,9 +557,18 @@ dpll_pin_alloc(u64 clock_id, u32 pin_idx, struct module *module, struct dpll_pin *pin; int ret; + if (pin_idx == DPLL_PIN_IDX_UNSPEC) { + ret = dpll_pin_idx_alloc(&pin_idx); + if (ret) + return ERR_PTR(ret); + } else if (pin_idx > INT_MAX) { + return ERR_PTR(-EINVAL); + } pin = kzalloc(sizeof(*pin), GFP_KERNEL); - if (!pin) - return ERR_PTR(-ENOMEM); + if (!pin) { + ret = -ENOMEM; + goto err_pin_alloc; + } pin->pin_idx = pin_idx; pin->clock_id = clock_id; pin->module = module; @@ -555,6 +596,8 @@ dpll_pin_alloc(u64 clock_id, u32 pin_idx, struct module *module, dpll_pin_prop_free(&pin->prop); err_pin_prop: kfree(pin); +err_pin_alloc: + dpll_pin_idx_free(pin_idx); return ERR_PTR(ret); } @@ -658,6 +701,7 @@ void dpll_pin_put(struct dpll_pin *pin) xa_destroy(&pin->ref_sync_pins); dpll_pin_prop_free(&pin->prop); fwnode_handle_put(pin->fwnode); + dpll_pin_idx_free(pin->pin_idx); kfree_rcu(pin, rcu); } mutex_unlock(&dpll_lock); diff --git a/include/linux/dpll.h b/include/linux/dpll.h index 34b005bb4df6f..a89a43aaea444 100644 --- a/include/linux/dpll.h +++ b/include/linux/dpll.h @@ -235,6 +235,8 @@ int dpll_device_register(struct dpll_device *dpll, enum dpll_type type, void dpll_device_unregister(struct dpll_device *dpll, const struct dpll_device_ops *ops, void *priv); +#define DPLL_PIN_IDX_UNSPEC U32_MAX + struct dpll_pin * dpll_pin_get(u64 clock_id, u32 dev_driver_id, struct module *module, const struct dpll_pin_properties *prop); -- 2.51.2
