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[93.34.88.103]) by smtp.googlemail.com with ESMTPSA id 5b1f17b1804b1-49230a458f2sm241451585e9.3.2026.06.18.05.58.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 18 Jun 2026 05:58:19 -0700 (PDT) From: Christian Marangi To: Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Simon Horman , Jonathan Corbet , Shuah Khan , Christian Marangi , Lorenzo Bianconi , Heiner Kallweit , Russell King , Saravana Kannan , Philipp Zabel , Nathan Chancellor , Nick Desaulniers , Bill Wendling , Justin Stitt , netdev@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, llvm@lists.linux.dev, Maxime Chevallier Subject: [RFC PATCH net-next v8 05/12] net: phylink: support late PCS provider attach Date: Thu, 18 Jun 2026 14:57:13 +0200 Message-ID: <20260618125752.1223-6-ansuelsmth@gmail.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260618125752.1223-1-ansuelsmth@gmail.com> References: <20260618125752.1223-1-ansuelsmth@gmail.com> Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Add support for late PCS provider attachment to a phylink instance. This works by creating a global notifier for the PCS provider and making each phylink instance that makes use of fwnode subscribe to this notifier. The PCS notifier will emit the event FWNODE_PCS_PROVIDER_ADD every time a new PCS provider is added. phylink will then react to this event and will call the new function fwnode_phylink_pcs_get_from_fwnode() that will check if the PCS fwnode provided by the event is present in the pcs-handle property of the phylink instance. If a related PCS is found, then such PCS is added to the phylink instance PCS list. Then we link the PCS to the phylink instance and we refresh the supported interfaces of the phylink instance. Finally we check if we are in a major_config_failed scenario and trigger an interface reconfiguration in the next phylink resolve. In the example scenario where the link was previously torn down due to removal of PCS, the link will be established again as the PCS came back and is now available to phylink. Signed-off-by: Christian Marangi --- drivers/net/pcs/pcs.c | 49 +++++++++++++++++++++++++++++ drivers/net/phy/phylink.c | 60 +++++++++++++++++++++++++++++++++++- include/linux/pcs/pcs.h | 65 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 173 insertions(+), 1 deletion(-) diff --git a/drivers/net/pcs/pcs.c b/drivers/net/pcs/pcs.c index 0cc4daf7beea..7a9d91b2a34d 100644 --- a/drivers/net/pcs/pcs.c +++ b/drivers/net/pcs/pcs.c @@ -22,6 +22,19 @@ struct fwnode_pcs_provider { static LIST_HEAD(fwnode_pcs_providers); static DEFINE_MUTEX(fwnode_pcs_mutex); +static BLOCKING_NOTIFIER_HEAD(fwnode_pcs_notify_list); + +int register_fwnode_pcs_notifier(struct notifier_block *nb) +{ + return blocking_notifier_chain_register(&fwnode_pcs_notify_list, nb); +} +EXPORT_SYMBOL_GPL(register_fwnode_pcs_notifier); + +int unregister_fwnode_pcs_notifier(struct notifier_block *nb) +{ + return blocking_notifier_chain_unregister(&fwnode_pcs_notify_list, nb); +} +EXPORT_SYMBOL_GPL(unregister_fwnode_pcs_notifier); struct phylink_pcs *fwnode_pcs_simple_get(struct fwnode_reference_args *pcsspec, void *data) @@ -55,6 +68,10 @@ int fwnode_pcs_add_provider(struct fwnode_handle *fwnode, fwnode_dev_initialized(fwnode, true); + blocking_notifier_call_chain(&fwnode_pcs_notify_list, + FWNODE_PCS_PROVIDER_ADD, + fwnode); + return 0; } EXPORT_SYMBOL_GPL(fwnode_pcs_add_provider); @@ -150,6 +167,38 @@ struct phylink_pcs *fwnode_pcs_get(struct fwnode_handle *fwnode, unsigned int in } EXPORT_SYMBOL_GPL(fwnode_pcs_get); +struct phylink_pcs * +fwnode_phylink_pcs_get_from_fwnode(struct fwnode_handle *fwnode, + struct fwnode_handle *pcs_fwnode) +{ + struct fwnode_reference_args pcsspec; + int index = 0; + int ret; + + /* Loop until we find a matching PCS node or + * fwnode_parse_pcsspec() returns error + * if we don't have any other PCS reference to check. + */ + while (true) { + ret = fwnode_parse_pcsspec(fwnode, index, NULL, &pcsspec); + if (ret) + return ERR_PTR(ret); + + /* Exit loop if we found the matching PCS node */ + if (pcsspec.fwnode == pcs_fwnode) { + fwnode_handle_put(pcsspec.fwnode); + break; + } + + /* Check the next PCS reference */ + fwnode_handle_put(pcsspec.fwnode); + index++; + } + + return fwnode_pcs_get(fwnode, index); +} +EXPORT_SYMBOL_GPL(fwnode_phylink_pcs_get_from_fwnode); + unsigned int fwnode_phylink_pcs_count(struct fwnode_handle *fwnode) { struct fwnode_reference_args out_args; diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c index 064d6f5a06da..b9a212bd1206 100644 --- a/drivers/net/phy/phylink.c +++ b/drivers/net/phy/phylink.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include #include @@ -62,6 +63,7 @@ struct phylink { /* List of available PCS */ struct list_head pcs_list; + struct notifier_block fwnode_pcs_nb; /* What interface are supported by the current link. * Can change on removal or addition of new PCS. @@ -2000,6 +2002,53 @@ static int phylink_fill_available_pcs(struct phylink *pl, return ret; } +static int pcs_provider_notify(struct notifier_block *self, + unsigned long val, void *data) +{ + struct phylink *pl = container_of(self, struct phylink, fwnode_pcs_nb); + struct fwnode_handle *pcs_fwnode = data; + struct phylink_pcs *pcs; + + rtnl_lock(); + + /* Check if the just added PCS provider is + * in the phylink instance pcs-handle property. + */ + pcs = fwnode_phylink_pcs_get_from_fwnode(dev_fwnode(pl->config->dev), + pcs_fwnode); + if (IS_ERR(pcs)) { + rtnl_unlock(); + return NOTIFY_DONE; + } + + /* Add the PCS */ + mutex_lock(&pl->state_mutex); + + /* Link PCS with phylink */ + list_add(&pcs->list, &pl->pcs_list); + pcs->phylink = pl; + + /* Refresh supported interfaces */ + phy_interface_copy(pl->supported_interfaces, + pl->config->supported_interfaces); + list_for_each_entry(pcs, &pl->pcs_list, list) + phy_interface_or(pl->supported_interfaces, + pl->supported_interfaces, + pcs->supported_interfaces); + + /* Force an interface reconfig if major config fail */ + if (pl->major_config_failed) + pl->force_major_config = true; + + mutex_unlock(&pl->state_mutex); + + rtnl_unlock(); + + phylink_run_resolve(pl); + + return NOTIFY_OK; +} + /** * phylink_create() - create a phylink instance * @config: a pointer to the target &struct phylink_config @@ -2124,6 +2173,12 @@ struct phylink *phylink_create(struct phylink_config *config, if (ret < 0) goto unlink_pcs_list; + /* Register notifier for late PCS attach */ + if (!phy_interface_empty(config->pcs_interfaces)) { + pl->fwnode_pcs_nb.notifier_call = pcs_provider_notify; + register_fwnode_pcs_notifier(&pl->fwnode_pcs_nb); + } + return pl; unlink_pcs_list: @@ -2152,10 +2207,13 @@ void phylink_destroy(struct phylink *pl) if (pl->link_gpio) gpiod_put(pl->link_gpio); + /* Unregister notifier for late PCS attach */ + if (pl->fwnode_pcs_nb.notifier_call) + unregister_fwnode_pcs_notifier(&pl->fwnode_pcs_nb); + cancel_work_sync(&pl->resolve); /* Drop link between PCS and phylink */ - /* Remove every PCS from phylink PCS list */ list_for_each_entry_safe(pcs, tmp, &pl->pcs_list, list) { pcs->phylink = NULL; list_del(&pcs->list); diff --git a/include/linux/pcs/pcs.h b/include/linux/pcs/pcs.h index b7cfdd680b2a..45e8f96662db 100644 --- a/include/linux/pcs/pcs.h +++ b/include/linux/pcs/pcs.h @@ -4,7 +4,36 @@ #include +enum fwnode_pcs_notify_event { + FWNODE_PCS_PROVIDER_ADD, +}; + #if IS_ENABLED(CONFIG_FWNODE_PCS) +/** + * register_fwnode_pcs_notifier - Register a notifier block for fwnode + * PCS events + * @nb: pointer to the notifier block + * + * Registers a notifier block to the fwnode_pcs_notify_list blocking + * notifier chain. This allows phylink instance to subscribe for + * PCS provider events. + * + * Returns: 0 or a negative error. + */ +int register_fwnode_pcs_notifier(struct notifier_block *nb); + +/** + * unregister_fwnode_pcs_notifier - Unregister a notifier block for fwnode + * PCS events + * @nb: pointer to the notifier block + * + * Unregisters a notifier block to the fwnode_pcs_notify_list blocking + * notifier chain. + * + * Returns: 0 or a negative error. + */ +int unregister_fwnode_pcs_notifier(struct notifier_block *nb); + /** * fwnode_pcs_get - Retrieves a PCS from a firmware node * @fwnode: firmware node @@ -20,6 +49,25 @@ struct phylink_pcs *fwnode_pcs_get(struct fwnode_handle *fwnode, unsigned int index); +/** + * fwnode_phylink_pcs_get_from_fwnode - Retrieves the PCS provided + * by the firmware node from a + * firmware node + * @fwnode: firmware node + * @pcs_fwnode: PCS firmware node + * + * Parse 'pcs-handle' in 'fwnode' and get the PCS that match + * 'pcs_fwnode' firmware node. + * + * Returns: a pointer to the phylink_pcs or a negative + * error pointer. Can return -EPROBE_DEFER if the PCS is not + * present in global providers list (either due to driver + * still needs to be probed or it failed to probe/removed) + */ +struct phylink_pcs * +fwnode_phylink_pcs_get_from_fwnode(struct fwnode_handle *fwnode, + struct fwnode_handle *pcs_fwnode); + /** * fwnode_phylink_pcs_count - count PCS entries described in firmware node * @fwnode: firmware node @@ -53,12 +101,29 @@ int fwnode_phylink_pcs_parse(struct fwnode_handle *fwnode, struct phylink_pcs **available_pcs, unsigned int num_pcs); #else +static inline int register_fwnode_pcs_notifier(struct notifier_block *nb) +{ + return -EOPNOTSUPP; +} + +static inline int unregister_fwnode_pcs_notifier(struct notifier_block *nb) +{ + return -EOPNOTSUPP; +} + static inline struct phylink_pcs *fwnode_pcs_get(struct fwnode_handle *fwnode, unsigned int index) { return ERR_PTR(-ENOENT); } +static inline struct phylink_pcs * +fwnode_phylink_pcs_get_from_fwnode(struct fwnode_handle *fwnode, + struct fwnode_handle *pcs_fwnode) +{ + return ERR_PTR(-ENOENT); +} + static inline unsigned int fwnode_phylink_pcs_count(struct fwnode_handle *fwnode) { return 0; -- 2.53.0