RE: [RFC PATCH v8 03/10] dpll: core: Add DPLL framework base functions

[Kubalewski, Arkadiusz]

>From: Jiri Pirko <jiri@xxxxxxxxxxx>
>Sent: Saturday, June 10, 2023 7:38 PM
>
>Fri, Jun 09, 2023 at 02:18:46PM CEST, arkadiusz.kubalewski@xxxxxxxxx wrote:
>>From: Vadim Fedorenko <vadim.fedorenko@xxxxxxxxx>
>>
>>DPLL framework is used to represent and configure DPLL devices
>>in systems. Each device that has DPLL and can configure inputs
>>and outputs can use this framework.
>>
>>Implement core framework functions for further interactions
>>with device drivers implementing dpll subsystem, as well as for
>>interactions of DPLL netlink framework part with the subsystem
>>itself.
>>
>>Co-developed-by: Milena Olech <milena.olech@xxxxxxxxx>
>>Signed-off-by: Milena Olech <milena.olech@xxxxxxxxx>
>>Co-developed-by: Michal Michalik <michal.michalik@xxxxxxxxx>
>>Signed-off-by: Michal Michalik <michal.michalik@xxxxxxxxx>
>>Signed-off-by: Vadim Fedorenko <vadim.fedorenko@xxxxxxxxx>
>>Co-developed-by: Arkadiusz Kubalewski <arkadiusz.kubalewski@xxxxxxxxx>
>>Signed-off-by: Arkadiusz Kubalewski <arkadiusz.kubalewski@xxxxxxxxx>
>>---
>> drivers/dpll/dpll_core.c | 953 +++++++++++++++++++++++++++++++++++++++
>> drivers/dpll/dpll_core.h | 104 +++++
>
>Overall, looks very good! I pinpointed couple of nits below, nothing big.
>General question: Why do you put documentation comment to every static
>function? Does not make any sense to me. Even for non-exported functions
>I think it is overkill. Most of them (if not all) give the reader no
>additional information and only make the code a bit harder to read.
>Care to drop them?
>
>
>> 2 files changed, 1057 insertions(+)
>> create mode 100644 drivers/dpll/dpll_core.c
>> create mode 100644 drivers/dpll/dpll_core.h
>>
>>diff --git a/drivers/dpll/dpll_core.c b/drivers/dpll/dpll_core.c
>>new file mode 100644
>>index 000000000000..ee515b7c18be
>>--- /dev/null
>>+++ b/drivers/dpll/dpll_core.c
>>@@ -0,0 +1,953 @@
>>+// SPDX-License-Identifier: GPL-2.0
>>+/*
>>+ *  dpll_core.c - Generic DPLL Management class support.
>
>What's "management class support"? Does not sound recognizable.
>

Fixed.

>
>>+ *
>>+ *  Copyright (c) 2023 Meta Platforms, Inc. and affiliates
>>+ *  Copyright (c) 2023 Intel Corporation.
>>+ */
>>+
>>+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>>+
>>+#include <linux/device.h>
>>+#include <linux/err.h>
>>+#include <linux/slab.h>
>>+#include <linux/string.h>
>>+
>>+#include "dpll_core.h"
>>+
>>+DEFINE_MUTEX(dpll_lock);
>>+
>>+DEFINE_XARRAY_FLAGS(dpll_device_xa, XA_FLAGS_ALLOC);
>>+DEFINE_XARRAY_FLAGS(dpll_pin_xa, XA_FLAGS_ALLOC);
>>+
>>+#define ASSERT_DPLL_REGISTERED(d) \
>>+	WARN_ON_ONCE(!xa_get_mark(&dpll_device_xa, (d)->id, DPLL_REGISTERED))
>>+#define ASSERT_DPLL_NOT_REGISTERED(d) \
>>+	WARN_ON_ONCE(xa_get_mark(&dpll_device_xa, (d)->id, DPLL_REGISTERED))
>>+
>>+/**
>>+ * dpll_device_get_by_id - find dpll device by it's id
>>+ * @id: id of searched dpll
>>+ *
>>+ * Context: shall be called under a lock (dpll_lock)
>>+ * Return:
>>+ * * dpll_device struct if found
>>+ * * NULL otherwise
>>+ */
>>+struct dpll_device *dpll_device_get_by_id(int id)
>>+{
>>+	if (xa_get_mark(&dpll_device_xa, id, DPLL_REGISTERED))
>>+		return xa_load(&dpll_device_xa, id);
>>+
>>+	return NULL;
>>+}
>>+
>>+/**
>>+ * dpll_pin_registration_find - find a pin registration record
>>+ * @ref: reference between dpll and pin
>>+ * @ops: searched pin ops pointer
>>+ * @priv: searched pin priv pointer
>>+ *
>>+ * Search dpll's registered pins for given ops and priv data.
>>+ *
>>+ * Context: shall be called under a lock (dpll_lock)
>>+ * Return:
>>+ * * NULL - if pin was not found
>>+ * * pointer to `struct dpll_pin_registration` if found
>>+ */
>>+static struct dpll_pin_registration *
>>+dpll_pin_registration_find(struct dpll_pin_ref *ref,
>>+			   const struct dpll_pin_ops *ops, void *priv)
>>+{
>>+	struct dpll_pin_registration *reg;
>>+
>>+	list_for_each_entry(reg, &ref->registration_list, list) {
>>+		if (reg->ops == ops && reg->priv == priv)
>>+			return reg;
>>+	}
>>+	return NULL;
>>+}
>>+
>>+/**
>>+ * dpll_xa_ref_pin_add - add pin reference to a given xarray
>>+ * @xa_pins: dpll_pin_ref xarray holding pins
>>+ * @pin: pin being added
>>+ * @ops: ops for a pin
>>+ * @priv: pointer to private data of owner
>>+ *
>>+ * Allocate and create reference of a pin and enlist a registration
>>+ * structure storing ops and priv pointers of a caller registant.
>>+ *
>>+ * Context: shall be called under a lock (dpll_lock)
>>+ * Return:
>>+ * * 0 on success
>>+ * * -ENOMEM on failed allocation
>>+ */
>>+static int
>>+dpll_xa_ref_pin_add(struct xarray *xa_pins, struct dpll_pin *pin,
>>+		    const struct dpll_pin_ops *ops, void *priv)
>>+{
>>+	struct dpll_pin_registration *reg;
>>+	struct dpll_pin_ref *ref;
>>+	bool ref_exists = false;
>>+	unsigned long i;
>>+	int ret;
>>+
>>+	xa_for_each(xa_pins, i, ref) {
>>+		if (ref->pin != pin)
>>+			continue;
>>+		reg = dpll_pin_registration_find(ref, ops, priv);
>>+		if (reg) {
>>+			refcount_inc(&ref->refcount);
>>+			return 0;
>>+		}
>>+		ref_exists = true;
>>+		break;
>>+	}
>>+
>>+	if (!ref_exists) {
>>+		ref = kzalloc(sizeof(*ref), GFP_KERNEL);
>>+		if (!ref)
>>+			return -ENOMEM;
>>+		ref->pin = pin;
>>+		INIT_LIST_HEAD(&ref->registration_list);
>>+		ret = xa_insert(xa_pins, pin->pin_idx, ref, GFP_KERNEL);
>>+		if (ret) {
>>+			kfree(ref);
>>+			return ret;
>>+		}
>>+		refcount_set(&ref->refcount, 1);
>>+	}
>>+
>>+	reg = kzalloc(sizeof(*reg), GFP_KERNEL);
>>+	if (!reg) {
>>+		if (!ref_exists)
>>+			kfree(ref);
>>+		return -ENOMEM;
>>+	}
>>+	reg->ops = ops;
>>+	reg->priv = priv;
>>+	if (ref_exists)
>
>If you set refcount to 0 couple of lines above, you can drop the check
>here.
>

Fixed.

>
>>+		refcount_inc(&ref->refcount);
>>+	list_add_tail(&reg->list, &ref->registration_list);
>>+
>>+	return 0;
>>+}
>>+
>>+/**
>>+ * dpll_xa_ref_pin_del - remove reference of a pin from xarray
>>+ * @xa_pins: dpll_pin_ref xarray holding pins
>>+ * @pin: pointer to a pin being removed
>>+ * @ops: pointer to ops of pin being removed
>>+ * @priv: pointer to private data of registerer who invoked pin removal
>>+ *
>>+ * Decrement refcount of existing pin reference on given xarray.
>>+ * If all registrations are lifted delete the reference and free its memory.
>>+ *
>>+ * Context: shall be called under a lock (dpll_lock)
>>+ * Return:
>>+ * * 0 on success
>>+ * * -EINVAL if reference to a pin was not found
>>+ */
>>+static int dpll_xa_ref_pin_del(struct xarray *xa_pins, struct dpll_pin
>>*pin,
>>+			       const struct dpll_pin_ops *ops, void *priv)
>>+{
>>+	struct dpll_pin_registration *reg;
>>+	struct dpll_pin_ref *ref;
>>+	unsigned long i;
>>+
>>+	xa_for_each(xa_pins, i, ref) {
>>+		if (ref->pin != pin)
>>+			continue;
>>+		reg = dpll_pin_registration_find(ref, ops, priv);
>>+		if (WARN_ON(!reg))
>>+			return -EINVAL;
>>+		if (refcount_dec_and_test(&ref->refcount)) {
>>+			list_del(&reg->list);
>>+			kfree(reg);
>>+			xa_erase(xa_pins, i);
>>+			WARN_ON(!list_empty(&ref->registration_list));
>>+			kfree(ref);
>>+		}
>>+		return 0;
>>+	}
>>+
>>+	return -EINVAL;
>>+}
>>+
>>+/**
>>+ * dpll_xa_ref_dpll_add - add dpll reference to a given xarray
>>+ * @xa_dplls: dpll_pin_ref xarray holding dplls
>>+ * @dpll: dpll being added
>>+ * @ops: pin-reference ops for a dpll
>>+ * @priv: pointer to private data of owner
>>+ *
>>+ * Allocate and create reference of a dpll-pin ops or increase refcount
>>+ * on existing dpll reference on given xarray.
>>+ *
>>+ * Context: shall be called under a lock (dpll_lock)
>>+ * Return:
>>+ * * 0 on success
>>+ * * -ENOMEM on failed allocation
>>+ */
>>+static int
>>+dpll_xa_ref_dpll_add(struct xarray *xa_dplls, struct dpll_device *dpll,
>>+		     const struct dpll_pin_ops *ops, void *priv)
>>+{
>>+	struct dpll_pin_registration *reg;
>>+	struct dpll_pin_ref *ref;
>>+	bool ref_exists = false;
>>+	unsigned long i;
>>+	int ret;
>>+
>>+	xa_for_each(xa_dplls, i, ref) {
>>+		if (ref->dpll != dpll)
>>+			continue;
>>+		reg = dpll_pin_registration_find(ref, ops, priv);
>>+		if (reg) {
>>+			refcount_inc(&ref->refcount);
>>+			return 0;
>>+		}
>>+		ref_exists = true;
>>+		break;
>>+	}
>>+
>>+	if (!ref_exists) {
>>+		ref = kzalloc(sizeof(*ref), GFP_KERNEL);
>>+		if (!ref)
>>+			return -ENOMEM;
>>+		ref->dpll = dpll;
>>+		INIT_LIST_HEAD(&ref->registration_list);
>>+		ret = xa_insert(xa_dplls, dpll->device_idx, ref, GFP_KERNEL);
>>+		if (ret) {
>>+			kfree(ref);
>>+			return ret;
>>+		}
>>+		refcount_set(&ref->refcount, 1);
>>+	}
>>+
>>+	reg = kzalloc(sizeof(*reg), GFP_KERNEL);
>>+	if (!reg) {
>>+		if (!ref_exists)
>>+			kfree(ref);
>>+		return -ENOMEM;
>>+	}
>>+	reg->ops = ops;
>>+	reg->priv = priv;
>>+	if (ref_exists)
>
>If you set refcount to 0 couple of lines above, you can drop the check
>here.
>

Fixed.

>
>>+		refcount_inc(&ref->refcount);
>>+	list_add_tail(&reg->list, &ref->registration_list);
>>+
>>+	return 0;
>>+}
>>+
>>+/**
>>+ * dpll_xa_ref_dpll_del - remove reference of a dpll from xarray
>>+ * @xa_dplls: dpll_pin_ref xarray holding dplls
>>+ * @dpll: pointer to a dpll to remove
>>+ * @ops: pointer to ops of dpll being removed
>>+ * @priv: pointer to private data of registerer who invoked dpll removal
>>+ *
>>+ * Decrement refcount of existing dpll reference on given xarray.
>>+ * If all references are dropped, delete the reference and free its memory.
>>+ *
>>+ * Context: shall be called under a lock (dpll_lock)
>>+ */
>>+static void
>>+dpll_xa_ref_dpll_del(struct xarray *xa_dplls, struct dpll_device *dpll,
>>+		     const struct dpll_pin_ops *ops, void *priv)
>>+{
>>+	struct dpll_pin_registration *reg;
>>+	struct dpll_pin_ref *ref;
>>+	unsigned long i;
>>+
>>+	xa_for_each(xa_dplls, i, ref) {
>>+		if (ref->dpll != dpll)
>>+			continue;
>>+		reg = dpll_pin_registration_find(ref, ops, priv);
>>+		if (WARN_ON(!reg))
>>+			return;
>>+		if (refcount_dec_and_test(&ref->refcount)) {
>>+			list_del(&reg->list);
>>+			kfree(reg);
>>+			xa_erase(xa_dplls, i);
>>+			WARN_ON(!list_empty(&ref->registration_list));
>>+			kfree(ref);
>>+		}
>>+		return;
>>+	}
>>+}
>>+
>>+/**
>>+ * dpll_xa_ref_dpll_find - find dpll reference on xarray
>>+ * @xa_refs: dpll_pin_ref xarray holding dpll references
>>+ * @dpll: pointer to a dpll being searched
>>+ *
>>+ * Search for dpll-pin ops reference struct of a given dpll on given xarray.
>>+ *
>>+ * Context: shall be called under a lock (dpll_lock)
>>+ * Return:
>>+ * * pin reference struct pointer on success
>>+ * * NULL - reference to a pin was not found
>>+ */
>>+struct dpll_pin_ref *
>>+dpll_xa_ref_dpll_find(struct xarray *xa_refs, const struct dpll_device *dpll)
>>+{
>>+	struct dpll_pin_ref *ref;
>>+	unsigned long i;
>>+
>>+	xa_for_each(xa_refs, i, ref) {
>>+		if (ref->dpll == dpll)
>>+			return ref;
>>+	}
>>+
>>+	return NULL;
>>+}
>>+
>>+/**
>>+ * dpll_xa_ref_dpll_first - find first record of given xarray
>>+ * @xa_refs: xarray
>>+ *
>>+ * Context: shall be called under a lock (dpll_lock)
>>+ * Return: first element on given xaaray
>>+ */
>>+struct dpll_pin_ref *dpll_xa_ref_dpll_first(struct xarray *xa_refs)
>>+{
>>+	struct dpll_pin_ref *ref;
>>+	unsigned long i = 0;
>>+
>>+	ref = xa_find(xa_refs, &i, ULONG_MAX, XA_PRESENT);
>>+	WARN_ON(!ref);
>>+	return ref;
>>+}
>>+
>>+/**
>>+ * dpll_device_alloc - allocate the memory for dpll device
>>+ * @clock_id: clock_id of creator
>>+ * @device_idx: id given by dev driver
>>+ * @module: reference to registering module
>>+ *
>>+ * Allocates memory and initialize dpll device, hold its reference on
>>global
>>+ * xarray.
>>+ *
>>+ * Context: shall be called under a lock (dpll_lock)
>>+ * Return:
>>+ * * valid dpll_device struct pointer if succeeded
>>+ * * ERR_PTR(-ENOMEM) - failed memory allocation
>>+ * * ERR_PTR(X) - failed allocation on dpll's xa
>>+ */
>>+static struct dpll_device *
>>+dpll_device_alloc(const u64 clock_id, u32 device_idx, struct module *module)
>>+{
>>+	struct dpll_device *dpll;
>>+	int ret;
>>+
>>+	dpll = kzalloc(sizeof(*dpll), GFP_KERNEL);
>>+	if (!dpll)
>>+		return ERR_PTR(-ENOMEM);
>>+	refcount_set(&dpll->refcount, 1);
>>+	INIT_LIST_HEAD(&dpll->registration_list);
>>+	dpll->device_idx = device_idx;
>>+	dpll->clock_id = clock_id;
>>+	dpll->module = module;
>>+	ret = xa_alloc(&dpll_device_xa, &dpll->id, dpll, xa_limit_16b,
>>+		       GFP_KERNEL);
>>+	if (ret) {
>>+		kfree(dpll);
>>+		return ERR_PTR(ret);
>>+	}
>>+	xa_init_flags(&dpll->pin_refs, XA_FLAGS_ALLOC);
>>+
>>+	return dpll;
>>+}
>>+
>>+/**
>>+ * dpll_device_get - find existing or create new dpll device
>>+ * @clock_id: clock_id of creator
>>+ * @device_idx: idx given by device driver
>>+ * @module: reference to registering module
>>+ *
>>+ * Get existing object of a dpll device, unique for given arguments.
>>+ * Create new if doesn't exist yet.
>>+ *
>>+ * Context: Acquires a lock (dpll_lock)
>>+ * Return:
>>+ * * valid dpll_device struct pointer if succeeded
>>+ * * ERR_PTR(-ENOMEM) - failed memory allocation
>>+ * * ERR_PTR(X) - failed allocation on dpll's xa
>>+ */
>>+struct dpll_device *
>>+dpll_device_get(u64 clock_id, u32 device_idx, struct module *module)
>>+{
>>+	struct dpll_device *dpll, *ret = NULL;
>>+	unsigned long index;
>>+
>>+	mutex_lock(&dpll_lock);
>>+	xa_for_each(&dpll_device_xa, index, dpll) {
>>+		if (dpll->clock_id == clock_id &&
>>+		    dpll->device_idx == device_idx &&
>>+		    dpll->module == module) {
>>+			ret = dpll;
>>+			refcount_inc(&ret->refcount);
>>+			break;
>>+		}
>>+	}
>>+	if (!ret)
>>+		ret = dpll_device_alloc(clock_id, device_idx, module);
>>+	mutex_unlock(&dpll_lock);
>>+
>>+	return ret;
>>+}
>>+EXPORT_SYMBOL_GPL(dpll_device_get);
>>+
>>+/**
>>+ * dpll_device_put - decrease the refcount and free memory if possible
>>+ * @dpll: dpll_device struct pointer
>>+ *
>>+ * Context: Acquires a lock (dpll_lock)
>>+ * Drop reference for a dpll device, if all references are gone, delete
>>+ * dpll device object.
>>+ */
>>+void dpll_device_put(struct dpll_device *dpll)
>>+{
>>+	if (!dpll)
>
>Drop this check and rely on a basic driver sanity. I'm pretty sure I
>asked you to drop checks like this during the last version review.
>

Fixed.

>
>>+		return;
>>+	mutex_lock(&dpll_lock);
>>+	if (refcount_dec_and_test(&dpll->refcount)) {
>>+		ASSERT_DPLL_NOT_REGISTERED(dpll);
>>+		WARN_ON_ONCE(!xa_empty(&dpll->pin_refs));
>>+		xa_destroy(&dpll->pin_refs);
>>+		xa_erase(&dpll_device_xa, dpll->id);
>>+		WARN_ON(!list_empty(&dpll->registration_list));
>>+		kfree(dpll);
>>+	}
>>+	mutex_unlock(&dpll_lock);
>>+}
>>+EXPORT_SYMBOL_GPL(dpll_device_put);
>>+
>>+static struct dpll_device_registration *
>>+dpll_device_registration_find(struct dpll_device *dpll,
>>+			      const struct dpll_device_ops *ops, void *priv)
>>+{
>>+	struct dpll_device_registration *reg;
>>+
>>+	list_for_each_entry(reg, &dpll->registration_list, list) {
>>+		if (reg->ops == ops && reg->priv == priv)
>>+			return reg;
>>+	}
>>+	return NULL;
>>+}
>>+
>>+/**
>>+ * dpll_device_register - register the dpll device in the subsystem
>>+ * @dpll: pointer to a dpll
>>+ * @type: type of a dpll
>>+ * @ops: ops for a dpll device
>>+ * @priv: pointer to private information of owner
>>+ *
>>+ * Make dpll device available for user space.
>>+ *
>>+ * Context: Acquires a lock (dpll_lock)
>>+ * Return:
>>+ * * 0 on success
>>+ * * -EINVAL on failure due to wrong arguments provided
>>+ * * -EEXIST if device was already registered
>>+ */
>>+int dpll_device_register(struct dpll_device *dpll, enum dpll_type type,
>>+			 const struct dpll_device_ops *ops, void *priv)
>>+{
>>+	struct dpll_device_registration *reg;
>>+	bool first_registration = false;
>>+
>>+	if (WARN_ON(!ops))
>>+		return -EINVAL;
>>+	if (WARN_ON(type < DPLL_TYPE_PPS || type > DPLL_TYPE_MAX))
>>+		return -EINVAL;
>>+
>>+	mutex_lock(&dpll_lock);
>>+	reg = dpll_device_registration_find(dpll, ops, priv);
>>+	if (reg) {
>>+		mutex_unlock(&dpll_lock);
>>+		return -EEXIST;
>>+	}
>>+
>>+	reg = kzalloc(sizeof(*reg), GFP_KERNEL);
>>+	if (!reg) {
>>+		mutex_unlock(&dpll_lock);
>>+		return -EEXIST;
>
>-ENOMEM;
>

Fixed.

>
>>+	}
>>+	reg->ops = ops;
>>+	reg->priv = priv;
>>+	dpll->type = type;
>>+	first_registration = list_empty(&dpll->registration_list);
>>+	list_add_tail(&reg->list, &dpll->registration_list);
>>+	if (!first_registration) {
>>+		mutex_unlock(&dpll_lock);
>>+		return 0;
>>+	}
>>+
>>+	xa_set_mark(&dpll_device_xa, dpll->id, DPLL_REGISTERED);
>>+	mutex_unlock(&dpll_lock);
>>+	dpll_device_create_ntf(dpll);
>>+
>>+	return 0;
>>+}
>>+EXPORT_SYMBOL_GPL(dpll_device_register);
>>+
>>+/**
>>+ * dpll_device_unregister - unregister dpll device
>>+ * @dpll: registered dpll pointer
>>+ * @ops: ops for a dpll device
>>+ * @priv: pointer to private information of owner
>>+ *
>>+ * Unregister device, make it unavailable for userspace.
>>+ * Note: It does not free the memory
>>+ * Context: Acquires a lock (dpll_lock)
>>+ */
>>+void dpll_device_unregister(struct dpll_device *dpll,
>>+			    const struct dpll_device_ops *ops, void *priv)
>>+{
>>+	struct dpll_device_registration *reg;
>>+
>>+	mutex_lock(&dpll_lock);
>>+	ASSERT_DPLL_REGISTERED(dpll);
>>+	dpll_device_delete_ntf(dpll);
>>+	reg = dpll_device_registration_find(dpll, ops, priv);
>>+	if (WARN_ON(!reg)) {
>>+		mutex_unlock(&dpll_lock);
>>+		return;
>>+	}
>>+	list_del(&reg->list);
>>+	kfree(reg);
>>+
>>+	if (!list_empty(&dpll->registration_list)) {
>>+		mutex_unlock(&dpll_lock);
>>+		return;
>>+	}
>>+	xa_clear_mark(&dpll_device_xa, dpll->id, DPLL_REGISTERED);
>>+	mutex_unlock(&dpll_lock);
>>+}
>>+EXPORT_SYMBOL_GPL(dpll_device_unregister);
>>+
>>+/**
>>+ * dpll_pin_alloc - allocate the memory for dpll pin
>>+ * @clock_id: clock_id of creator
>>+ * @pin_idx: idx given by dev driver
>>+ * @module: reference to registering module
>>+ * @prop: dpll pin properties
>>+ *
>>+ * Context: shall be called under a lock (dpll_lock)
>>+ * Return:
>>+ * * valid allocated dpll_pin struct pointer if succeeded
>>+ * * ERR_PTR(-ENOMEM) - failed memory allocation
>>+ * * ERR_PTR(-EINVAL) - wrong pin type property value
>>+ */
>>+static struct dpll_pin *
>>+dpll_pin_alloc(u64 clock_id, u32 pin_idx, struct module *module,
>>+	       const struct dpll_pin_properties *prop)
>>+{
>>+	struct dpll_pin *pin;
>>+	int ret;
>>+
>>+	pin = kzalloc(sizeof(*pin), GFP_KERNEL);
>>+	if (!pin)
>>+		return ERR_PTR(-ENOMEM);
>>+	pin->pin_idx = pin_idx;
>>+	pin->clock_id = clock_id;
>>+	pin->module = module;
>>+	if (WARN_ON(prop->type < DPLL_PIN_TYPE_MUX ||
>>+		    prop->type > DPLL_PIN_TYPE_MAX)) {
>>+		ret = -EINVAL;
>>+		goto err;
>>+	}
>>+	pin->prop = prop;
>>+	refcount_set(&pin->refcount, 1);
>>+	xa_init_flags(&pin->dpll_refs, XA_FLAGS_ALLOC);
>>+	xa_init_flags(&pin->parent_refs, XA_FLAGS_ALLOC);
>>+	ret = xa_alloc(&dpll_pin_xa, &pin->id, pin, xa_limit_16b, GFP_KERNEL);
>>+	if (ret)
>>+		goto err;
>>+	return pin;
>>+err:
>>+	xa_destroy(&pin->dpll_refs);
>>+	xa_destroy(&pin->parent_refs);
>>+	kfree(pin);
>>+	return ERR_PTR(ret);
>>+}
>>+
>>+/**
>>+ * dpll_pin_get - find existing or create new dpll pin
>>+ * @clock_id: clock_id of creator
>>+ * @pin_idx: idx given by dev driver
>>+ * @module: reference to registering module
>>+ * @prop: dpll pin properties
>>+ *
>>+ * Get existing object of a pin (unique for given arguments) or create new
>>+ * if doesn't exist yet.
>>+ *
>>+ * Context: shall be called under a lock (dpll_lock)
>>+ * Return:
>>+ * * valid allocated dpll_pin struct pointer if succeeded
>>+ * * ERR_PTR of an error
>>+ */
>>+struct dpll_pin *
>>+dpll_pin_get(u64 clock_id, u32 pin_idx, struct module *module,
>>+	     const struct dpll_pin_properties *prop)
>>+{
>>+	struct dpll_pin *pos, *ret = NULL;
>>+	unsigned long i;
>>+
>>+	xa_for_each(&dpll_pin_xa, i, pos) {
>>+		if (pos->clock_id == clock_id &&
>>+		    pos->pin_idx == pin_idx &&
>>+		    pos->module == module) {
>>+			ret = pos;
>>+			refcount_inc(&ret->refcount);
>>+			break;
>>+		}
>>+	}
>>+	if (!ret)
>>+		ret = dpll_pin_alloc(clock_id, pin_idx, module, prop);
>>+
>>+	return ret;
>>+}
>>+EXPORT_SYMBOL_GPL(dpll_pin_get);
>>+
>>+/**
>>+ * dpll_pin_put - decrease the refcount and free memory if possible
>>+ * @pin: pointer to a pin to be put
>>+ *
>>+ * Drop reference for a pin, if all references are gone, delete pin object.
>>+ *
>>+ * Context: shall be called under a lock (dpll_lock)
>>+ */
>>+void dpll_pin_put(struct dpll_pin *pin)
>>+{
>>+	if (!pin)
>
>Drop this check.
>

Fixed.

>
>>+		return;
>>+	if (refcount_dec_and_test(&pin->refcount)) {
>>+		xa_destroy(&pin->dpll_refs);
>>+		xa_destroy(&pin->parent_refs);
>>+		xa_erase(&dpll_pin_xa, pin->id);
>>+		kfree(pin);
>>+	}
>>+}
>>+EXPORT_SYMBOL_GPL(dpll_pin_put);
>>+
>>+static int
>>+__dpll_pin_register(struct dpll_device *dpll, struct dpll_pin *pin,
>>+		    const struct dpll_pin_ops *ops, void *priv)
>>+{
>>+	int ret;
>>+
>>+	if (WARN_ON(!ops))
>>+		return -EINVAL;
>>+
>>+	ret = dpll_xa_ref_pin_add(&dpll->pin_refs, pin, ops, priv);
>>+	if (ret)
>>+		return ret;
>>+	ret = dpll_xa_ref_dpll_add(&pin->dpll_refs, dpll, ops, priv);
>>+	if (ret)
>>+		goto ref_pin_del;
>>+	else
>>+		dpll_pin_create_ntf(pin);
>>+
>>+	return ret;
>>+
>>+ref_pin_del:
>>+	dpll_xa_ref_pin_del(&dpll->pin_refs, pin, ops, priv);
>>+	return ret;
>>+}
>>+
>>+/**
>>+ * dpll_pin_register - register the dpll pin in the subsystem
>>+ * @dpll: pointer to a dpll
>>+ * @pin: pointer to a dpll pin
>>+ * @ops: ops for a dpll pin ops
>>+ * @priv: pointer to private information of owner
>>+ *
>>+ * Context: Acquires a lock (dpll_lock)
>>+ * Return:
>>+ * * 0 on success
>>+ * * -EINVAL - missing pin ops
>>+ * * -ENOMEM - failed to allocate memory
>>+ */
>>+int
>>+dpll_pin_register(struct dpll_device *dpll, struct dpll_pin *pin,
>>+		  const struct dpll_pin_ops *ops, void *priv)
>>+{
>>+	int ret;
>>+
>>+	mutex_lock(&dpll_lock);
>>+	if (WARN_ON(!(dpll->module == pin->module &&
>>+		      dpll->clock_id == pin->clock_id)))
>>+		ret = -EFAULT;
>
>In other cases like this you return -EINVAL. I think it is better. One
>way or another, be consistent please.
>

Fixed.

>
>>+	else
>>+		ret = __dpll_pin_register(dpll, pin, ops, priv);
>>+	mutex_unlock(&dpll_lock);
>>+
>>+	return ret;
>>+}
>>+EXPORT_SYMBOL_GPL(dpll_pin_register);
>>+
>>+static void
>>+__dpll_pin_unregister(struct dpll_device *dpll, struct dpll_pin *pin,
>>+		      const struct dpll_pin_ops *ops, void *priv)
>>+{
>>+	dpll_xa_ref_pin_del(&dpll->pin_refs, pin, ops, priv);
>>+	dpll_xa_ref_dpll_del(&pin->dpll_refs, dpll, ops, priv);
>>+}
>>+
>>+/**
>>+ * dpll_pin_unregister - unregister dpll pin from dpll device
>>+ * @dpll: registered dpll pointer
>>+ * @pin: pointer to a pin
>>+ * @ops: ops for a dpll pin
>>+ * @priv: pointer to private information of owner
>>+ *
>>+ * Note: It does not free the memory
>>+ * Context: Acquires a lock (dpll_lock)
>>+ */
>>+void dpll_pin_unregister(struct dpll_device *dpll, struct dpll_pin *pin,
>>+			 const struct dpll_pin_ops *ops, void *priv)
>>+{
>>+	if (WARN_ON(xa_empty(&dpll->pin_refs)))
>>+		return;
>>+
>>+	mutex_lock(&dpll_lock);
>>+	__dpll_pin_unregister(dpll, pin, ops, priv);
>>+	mutex_unlock(&dpll_lock);
>>+}
>>+EXPORT_SYMBOL_GPL(dpll_pin_unregister);
>>+
>>+/**
>>+ * dpll_pin_on_pin_register - register a pin with a parent pin
>>+ * @parent: pointer to a parent pin
>>+ * @pin: pointer to a pin
>>+ * @ops: ops for a dpll pin
>>+ * @priv: pointer to private information of owner
>>+ *
>>+ * Register a pin with a parent pin, create references between them and
>>+ * between newly registered pin and dplls connected with a parent pin.
>>+ *
>>+ * Context: Acquires a lock (dpll_lock)
>>+ * Return:
>>+ * * 0 on success
>>+ * * -EINVAL missing pin or parent
>>+ * * -ENOMEM failed allocation
>>+ * * -EPERM if parent is not allowed
>>+ */
>>+int dpll_pin_on_pin_register(struct dpll_pin *parent, struct dpll_pin *pin,
>>+			     const struct dpll_pin_ops *ops, void *priv)
>>+{
>>+	struct dpll_pin_ref *ref;
>>+	unsigned long i, stop;
>>+	int ret;
>>+
>>+	if (WARN_ON(parent->prop->type != DPLL_PIN_TYPE_MUX))
>>+		return -EINVAL;
>>+	ret = dpll_xa_ref_pin_add(&pin->parent_refs, parent, ops, priv);
>>+	if (ret)
>>+		goto unlock;
>>+	refcount_inc(&pin->refcount);
>>+	xa_for_each(&parent->dpll_refs, i, ref) {
>>+		mutex_lock(&dpll_lock);
>>+		ret = __dpll_pin_register(ref->dpll, pin, ops, priv);
>>+		mutex_unlock(&dpll_lock);
>>+		if (ret) {
>>+			stop = i;
>>+			goto dpll_unregister;
>>+		}
>>+		dpll_pin_create_ntf(pin);
>>+	}
>>+
>>+	return ret;
>>+
>>+dpll_unregister:
>>+	xa_for_each(&parent->dpll_refs, i, ref) {
>>+		if (i < stop) {
>>+			mutex_lock(&dpll_lock);
>>+			__dpll_pin_unregister(ref->dpll, pin, ops, priv);
>>+			mutex_unlock(&dpll_lock);
>>+		}
>>+	}
>>+	refcount_dec(&pin->refcount);
>>+	dpll_xa_ref_pin_del(&pin->parent_refs, parent, ops, priv);
>>+unlock:
>>+	return ret;
>>+}
>>+EXPORT_SYMBOL_GPL(dpll_pin_on_pin_register);
>>+
>>+/**
>>+ * dpll_pin_on_pin_unregister - unregister dpll pin from a parent pin
>>+ * @parent: pointer to a parent pin
>>+ * @pin: pointer to a pin
>>+ * @ops: ops for a dpll pin
>>+ * @priv: pointer to private information of owner
>>+ *
>>+ * Context: Acquires a lock (dpll_lock)
>>+ * Note: It does not free the memory
>>+ */
>>+void dpll_pin_on_pin_unregister(struct dpll_pin *parent, struct dpll_pin
>>*pin,
>>+				const struct dpll_pin_ops *ops, void *priv)
>>+{
>>+	struct dpll_pin_ref *ref;
>>+	unsigned long i;
>>+
>>+	mutex_lock(&dpll_lock);
>>+	dpll_pin_delete_ntf(pin);
>>+	dpll_xa_ref_pin_del(&pin->parent_refs, parent, ops, priv);
>>+	refcount_dec(&pin->refcount);
>>+	xa_for_each(&pin->dpll_refs, i, ref) {
>>+		__dpll_pin_unregister(ref->dpll, pin, ops, priv);
>>+	}
>
>Drop "{}"s for one line statement. Didn't checkpack warn you?
>

Fixed.

>
>>+	mutex_unlock(&dpll_lock);
>>+}
>>+EXPORT_SYMBOL_GPL(dpll_pin_on_pin_unregister);
>>+
>>+
>>+/**
>>+ * dpll_device_registration_first - get first registration of dpll device
>>+ * @dpll: pointer to a dpll
>>+ *
>>+ * Context: shall be called under a lock (dpll_lock)
>>+ * Return: pointer to the first registration of a dpll
>>+ */
>>+static struct dpll_device_registration *
>>+dpll_device_registration_first(struct dpll_device *dpll)
>>+{
>>+	struct dpll_device_registration *reg;
>>+
>>+	reg = list_first_entry_or_null((struct list_head *) &dpll-
>>registration_list,
>>+				       struct dpll_device_registration, list);
>>+	WARN_ON(!reg);
>>+	return reg;
>>+}
>>+
>>+/**
>>+ * dpll_priv - get the dpll device private owner data
>>+ * @dpll: registered dpll pointer
>>+ *
>>+ * Context: shall be called under a lock (dpll_lock)
>>+ * Return: pointer to the first registration priv data
>>+ */
>>+void *dpll_priv(struct dpll_device *dpll)
>>+{
>>+	struct dpll_device_registration *reg;
>>+
>>+	reg = dpll_device_registration_first(dpll);
>>+	return reg->priv;
>>+}
>>+
>>+/**
>>+ * dpll_device_ops - get the dpll device ops pointer
>>+ * @dpll: registered dpll pointer
>>+ *
>>+ * Context: shall be called under a lock (dpll_lock)
>>+ * Return: pointer to the first registration ops of the dpll
>>+ */
>>+const struct dpll_device_ops *dpll_device_ops(struct dpll_device *dpll)
>>+{
>>+	struct dpll_device_registration *reg;
>>+
>>+	reg = dpll_device_registration_first(dpll);
>>+	return reg->ops;
>>+}
>>+
>>+/**
>>+ * dpll_pin_registration_first - get first registration of dpll pin ref
>>+ * @ref: pointer to a pin ref struct
>>+ *
>>+ * Context: shall be called under a lock (dpll_lock)
>>+ * Return: pointer to the first registration of a dpll_pin_ref
>>+ */
>>+static struct dpll_pin_registration *
>>+dpll_pin_registration_first(struct dpll_pin_ref *ref)
>>+{
>>+	struct dpll_pin_registration *reg;
>>+
>>+	reg = list_first_entry_or_null(&ref->registration_list,
>>+				       struct dpll_pin_registration, list);
>>+	WARN_ON(!reg);
>>+	return reg;
>>+}
>>+
>>+/**
>>+ * dpll_pin_on_dpll_priv - get the dpll device private owner data
>>+ * @dpll:      registered dpll pointer
>>+ * @pin:       pointer to a pin
>>+ *
>>+ * Context: shall be called under a lock (dpll_lock)
>>+ * Return: pointer to the data
>>+ */
>>+void *dpll_pin_on_dpll_priv(struct dpll_device *dpll,
>>+			    struct dpll_pin *pin)
>>+{
>>+	struct dpll_pin_registration *reg;
>>+	struct dpll_pin_ref *ref;
>>+
>>+	ref = xa_load(&dpll->pin_refs, pin->pin_idx);
>>+	if (!ref)
>>+		return NULL;
>>+	reg = dpll_pin_registration_first(ref);
>>+	return reg->priv;
>>+}
>>+
>>+/**
>>+ * dpll_pin_on_pin_priv - get the dpll pin private owner data
>>+ * @parent: pointer to a parent pin
>>+ * @pin: pointer to a pin
>>+ *
>>+ * Context: shall be called under a lock (dpll_lock)
>>+ * Return: pointer to the data
>>+ */
>>+void *dpll_pin_on_pin_priv(struct dpll_pin *parent,
>>+			   struct dpll_pin *pin)
>>+{
>>+	struct dpll_pin_registration *reg;
>>+	struct dpll_pin_ref *ref;
>>+
>>+	ref = xa_load(&pin->parent_refs, parent->pin_idx);
>>+	if (!ref)
>>+		return NULL;
>>+	reg = dpll_pin_registration_first(ref);
>>+	return reg->priv;
>>+}
>>+
>>+/**
>>+ * dpll_pin_ops - get the pin ops pointer
>>+ * @ref: dpll pin ref
>>+ *
>>+ * Context: shall be called under a lock (dpll_lock)
>>+ * Return: pointer to the first ops registered with the pin
>>+ */
>>+const struct dpll_pin_ops *dpll_pin_ops(struct dpll_pin_ref *ref)
>>+{
>>+	struct dpll_pin_registration *reg;
>>+
>>+	reg = dpll_pin_registration_first(ref);
>>+	return reg->ops;
>>+}
>>+
>>+/**
>>+ * dpll_init - initialize dpll subsystem
>>+ *
>>+ * Return:
>>+ * 0 - success
>>+ * negative - netlink init error
>>+ */
>>+static int __init dpll_init(void)
>>+{
>>+	int ret;
>>+
>>+	ret = dpll_netlink_init();
>>+	if (ret)
>>+		goto error;
>>+
>>+	return 0;
>>+
>>+error:
>>+	mutex_destroy(&dpll_lock);
>>+	return ret;
>>+}
>>+subsys_initcall(dpll_init);
>>diff --git a/drivers/dpll/dpll_core.h b/drivers/dpll/dpll_core.h
>>new file mode 100644
>>index 000000000000..ef95e272937c
>>--- /dev/null
>>+++ b/drivers/dpll/dpll_core.h
>>@@ -0,0 +1,104 @@
>>+/* SPDX-License-Identifier: GPL-2.0 */
>>+/*
>>+ *  Copyright (c) 2023 Meta Platforms, Inc. and affiliates
>>+ *  Copyright (c) 2023 Intel and affiliates
>>+ */
>>+
>>+#ifndef __DPLL_CORE_H__
>>+#define __DPLL_CORE_H__
>>+
>>+#include <linux/dpll.h>
>>+#include <linux/list.h>
>>+#include <linux/refcount.h>
>>+#include "dpll_netlink.h"
>>+
>>+#define DPLL_REGISTERED		XA_MARK_1
>>+
>>+struct dpll_device_registration {
>>+	struct list_head list;
>>+	const struct dpll_device_ops *ops;
>>+	void *priv;
>
>You don't need this struct in the header. Move to .c
>

Fixed.

>
>>+};
>>+
>>+/**
>>+ * struct dpll_device - stores DPLL device internal data
>>+ * @id:			unique id number for each device given by kernel
>
>Who's kernel? Say "dpll subsystem" instead.
>

Fixed.

>
>>+ * @device_idx:		id given by dev driver
>>+ * @clock_id:		unique identifier (clock_id) of a dpll
>>+ * @module:		module of creator
>>+ * @type:		type of a dpll
>>+ * @pin_refs:		stores pins registered within a dpll
>>+ * @mode_supported_mask: mask of supported modes
>>+ * @refcount:		refcount
>>+ * @registration_list:	list of registered ops and priv data of dpll
>>owners
>>+ **/
>>+struct dpll_device {
>>+	u32 id;
>>+	u32 device_idx;
>>+	u64 clock_id;
>>+	struct module *module;
>>+	enum dpll_type type;
>>+	struct xarray pin_refs;
>>+	unsigned long mode_supported_mask;
>>+	refcount_t refcount;
>>+	struct list_head registration_list;
>>+};
>>+
>>+/**
>>+ * struct dpll_pin - structure for a dpll pin
>>+ * @id:			unique id number for pin given by kernel
>
>Who's kernel? Say "dpll subsystem" instead.
>

Fixed.

>
>>+ * @pin_idx:		index of a pin given by dev driver
>>+ * @clock_id:		clock_id of creator
>>+ * @module:		module of creator
>>+ * @dpll_refs:		hold referencees to dplls pin was registered with
>>+ * @parent_refs:	hold references to parent pins pin was registered with
>>+ * @prop:		pointer to pin properties given by registerer
>>+ * @rclk_dev_name:	holds name of device when pin can recover clock from it
>>+ * @refcount:		refcount
>>+ **/
>>+struct dpll_pin {
>>+	u32 id;
>>+	u32 pin_idx;
>>+	u64 clock_id;
>>+	struct module *module;
>>+	struct xarray dpll_refs;
>>+	struct xarray parent_refs;
>>+	const struct dpll_pin_properties *prop;
>>+	char *rclk_dev_name;
>>+	refcount_t refcount;
>>+};
>>+
>>+struct dpll_pin_registration {
>>+	struct list_head list;
>>+	const struct dpll_pin_ops *ops;
>>+	void *priv;
>>+};
>
>You don't need this struct in the header. Move to .c
>

Fixed.

Thank you,
Arkadiusz

>
>>+
>>+/**
>>+ * struct dpll_pin_ref - structure for referencing either dpll or pins
>>+ * @dpll:		pointer to a dpll
>>+ * @pin:		pointer to a pin
>>+ * @registration_list:	list of ops and priv data registered with the
>>ref
>>+ * @refcount:		refcount
>>+ **/
>>+struct dpll_pin_ref {
>>+	union {
>>+		struct dpll_device *dpll;
>>+		struct dpll_pin *pin;
>>+	};
>>+	struct list_head registration_list;
>>+	refcount_t refcount;
>>+};
>>+
>>+void *dpll_priv(struct dpll_device *dpll);
>>+void *dpll_pin_on_dpll_priv(struct dpll_device *dpll, struct dpll_pin *pin);
>>+void *dpll_pin_on_pin_priv(struct dpll_pin *parent, struct dpll_pin *pin);
>>+
>>+const struct dpll_device_ops *dpll_device_ops(struct dpll_device *dpll);
>>+struct dpll_device *dpll_device_get_by_id(int id);
>>+const struct dpll_pin_ops *dpll_pin_ops(struct dpll_pin_ref *ref);
>>+struct dpll_pin_ref *dpll_xa_ref_dpll_first(struct xarray *xa_refs);
>>+extern struct xarray dpll_device_xa;
>>+extern struct xarray dpll_pin_xa;
>>+extern struct mutex dpll_lock;
>>+#endif
>>--
>>2.37.3
>>