Commit 711696b3 authored by Ivan Vecera's avatar Ivan Vecera Committed by Paolo Abeni
Browse files

dpll: Support dynamic pin index allocation 



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().

Reviewed-by: default avatarAleksandr Loktionov <aleksandr.loktionov@intel.com>
Signed-off-by: default avatarIvan Vecera <ivecera@redhat.com>
Reviewed-by: default avatarArkadiusz Kubalewski <arkadiusz.kubalewski@intel.com>
Link: https://patch.msgid.link/20260203174002.705176-5-ivecera@redhat.com


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent 2be46758

drivers/dpll/dpll_core.c

+46 −2
Original line number Diff line number Diff line
@@ -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;
@@ -464,6 +466,36 @@ 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 -= (u32)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);
@@ -521,9 +553,18 @@ 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;
@@ -551,6 +592,8 @@ 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);

}
@@ -654,6 +697,7 @@ 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);

include/linux/dpll.h

+2 −0
Original line number Diff line number Diff line
@@ -240,6 +240,8 @@ 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);