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Message-ID: <20191108174551.GZ25745@shell.armlinux.org.uk>
Date: Fri, 8 Nov 2019 17:45:51 +0000
From: Russell King - ARM Linux admin <linux@...linux.org.uk>
To: Andrew Lunn <andrew@...n.ch>,
Florian Fainelli <f.fainelli@...il.com>,
Heiner Kallweit <hkallweit1@...il.com>
Cc: "David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org
Subject: Re: [PATCH] net: sfp: rework upstream interface
Sorry, this should've been for net-next.
On Fri, Nov 08, 2019 at 05:39:29PM +0000, Russell King wrote:
> The current upstream interface is an all-or-nothing, which is
> sub-optimal for future changes, as it doesn't allow the upstream driver
> to prepare for the SFP module becoming available, as it is at boot.
>
> Switch to a find-sfp-bus, add-upstream, del-upstream, put-sfp-bus
> interface structure instead, which allows the upstream driver to
> prepare for a module being available as soon as add-upstream is called.
>
> Signed-off-by: Russell King <rmk+kernel@...linux.org.uk>
> ---
> drivers/net/phy/phylink.c | 10 +++--
> drivers/net/phy/sfp-bus.c | 92 +++++++++++++++++++++++++++------------
> include/linux/sfp.h | 25 +++++++----
> 3 files changed, 88 insertions(+), 39 deletions(-)
>
> diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
> index 4c5e8b4f8d80..2b70b4d50573 100644
> --- a/drivers/net/phy/phylink.c
> +++ b/drivers/net/phy/phylink.c
> @@ -551,7 +551,7 @@ static int phylink_register_sfp(struct phylink *pl,
> struct sfp_bus *bus;
> int ret;
>
> - bus = sfp_register_upstream_node(fwnode, pl, &sfp_phylink_ops);
> + bus = sfp_bus_find_fwnode(fwnode);
> if (IS_ERR(bus)) {
> ret = PTR_ERR(bus);
> phylink_err(pl, "unable to attach SFP bus: %d\n", ret);
> @@ -560,7 +560,10 @@ static int phylink_register_sfp(struct phylink *pl,
>
> pl->sfp_bus = bus;
>
> - return 0;
> + ret = sfp_bus_add_upstream(bus, pl, &sfp_phylink_ops);
> + sfp_bus_put(bus);
> +
> + return ret;
> }
>
> /**
> @@ -654,8 +657,7 @@ EXPORT_SYMBOL_GPL(phylink_create);
> */
> void phylink_destroy(struct phylink *pl)
> {
> - if (pl->sfp_bus)
> - sfp_unregister_upstream(pl->sfp_bus);
> + sfp_bus_del_upstream(pl->sfp_bus);
> if (pl->link_gpio)
> gpiod_put(pl->link_gpio);
>
> diff --git a/drivers/net/phy/sfp-bus.c b/drivers/net/phy/sfp-bus.c
> index d037aab6a71d..715d45214e18 100644
> --- a/drivers/net/phy/sfp-bus.c
> +++ b/drivers/net/phy/sfp-bus.c
> @@ -329,10 +329,19 @@ static void sfp_bus_release(struct kref *kref)
> kfree(bus);
> }
>
> -static void sfp_bus_put(struct sfp_bus *bus)
> +/**
> + * sfp_bus_put() - put a reference on the &struct sfp_bus
> + * bus: the &struct sfp_bus found via sfp_bus_find_fwnode()
> + *
> + * Put a reference on the &struct sfp_bus and free the underlying structure
> + * if this was the last reference.
> + */
> +void sfp_bus_put(struct sfp_bus *bus)
> {
> - kref_put_mutex(&bus->kref, sfp_bus_release, &sfp_mutex);
> + if (bus)
> + kref_put_mutex(&bus->kref, sfp_bus_release, &sfp_mutex);
> }
> +EXPORT_SYMBOL_GPL(sfp_bus_put);
>
> static int sfp_register_bus(struct sfp_bus *bus)
> {
> @@ -348,11 +357,11 @@ static int sfp_register_bus(struct sfp_bus *bus)
> return ret;
> }
> }
> + bus->registered = true;
> bus->socket_ops->attach(bus->sfp);
> if (bus->started)
> bus->socket_ops->start(bus->sfp);
> bus->upstream_ops->attach(bus->upstream, bus);
> - bus->registered = true;
> return 0;
> }
>
> @@ -446,13 +455,12 @@ static void sfp_upstream_clear(struct sfp_bus *bus)
> }
>
> /**
> - * sfp_register_upstream_node() - parse and register the neighbouring device
> + * sfp_bus_find_fwnode() - parse and locate the SFP bus from fwnode
> * @fwnode: firmware node for the parent device (MAC or PHY)
> - * @upstream: the upstream private data
> - * @ops: the upstream's &struct sfp_upstream_ops
> *
> - * Parse the parent device's firmware node for a SFP bus, and register the
> - * SFP bus using sfp_register_upstream().
> + * Parse the parent device's firmware node for a SFP bus, and locate
> + * the sfp_bus structure, incrementing its reference count. This must
> + * be put via sfp_bus_put() when done.
> *
> * Returns: on success, a pointer to the sfp_bus structure,
> * %NULL if no SFP is specified,
> @@ -462,9 +470,7 @@ static void sfp_upstream_clear(struct sfp_bus *bus)
> * %-ENOMEM if we failed to allocate the bus.
> * an error from the upstream's connect_phy() method.
> */
> -struct sfp_bus *sfp_register_upstream_node(struct fwnode_handle *fwnode,
> - void *upstream,
> - const struct sfp_upstream_ops *ops)
> +struct sfp_bus *sfp_bus_find_fwnode(struct fwnode_handle *fwnode)
> {
> struct fwnode_reference_args ref;
> struct sfp_bus *bus;
> @@ -482,7 +488,39 @@ struct sfp_bus *sfp_register_upstream_node(struct fwnode_handle *fwnode,
> if (!bus)
> return ERR_PTR(-ENOMEM);
>
> + return bus;
> +}
> +EXPORT_SYMBOL_GPL(sfp_bus_find_fwnode);
> +
> +/**
> + * sfp_bus_add_upstream() - parse and register the neighbouring device
> + * @bus: the &struct sfp_bus found via sfp_bus_find_fwnode()
> + * @upstream: the upstream private data
> + * @ops: the upstream's &struct sfp_upstream_ops
> + *
> + * Add upstream driver for the SFP bus, and if the bus is complete, register
> + * the SFP bus using sfp_register_upstream(). This takes a reference on the
> + * bus, so it is safe to put the bus after this call.
> + *
> + * Returns: on success, a pointer to the sfp_bus structure,
> + * %NULL if no SFP is specified,
> + * on failure, an error pointer value:
> + * corresponding to the errors detailed for
> + * fwnode_property_get_reference_args().
> + * %-ENOMEM if we failed to allocate the bus.
> + * an error from the upstream's connect_phy() method.
> + */
> +int sfp_bus_add_upstream(struct sfp_bus *bus, void *upstream,
> + const struct sfp_upstream_ops *ops)
> +{
> + int ret;
> +
> + /* If no bus, return success */
> + if (!bus)
> + return 0;
> +
> rtnl_lock();
> + kref_get(&bus->kref);
> bus->upstream_ops = ops;
> bus->upstream = upstream;
>
> @@ -495,33 +533,33 @@ struct sfp_bus *sfp_register_upstream_node(struct fwnode_handle *fwnode,
> }
> rtnl_unlock();
>
> - if (ret) {
> + if (ret)
> sfp_bus_put(bus);
> - bus = ERR_PTR(ret);
> - }
>
> - return bus;
> + return ret;
> }
> -EXPORT_SYMBOL_GPL(sfp_register_upstream_node);
> +EXPORT_SYMBOL_GPL(sfp_bus_add_upstream);
>
> /**
> - * sfp_unregister_upstream() - Unregister sfp bus
> + * sfp_bus_del_upstream() - Delete a sfp bus
> * @bus: a pointer to the &struct sfp_bus structure for the sfp module
> *
> - * Unregister a previously registered upstream connection for the SFP
> - * module. @bus is returned from sfp_register_upstream().
> + * Delete a previously registered upstream connection for the SFP
> + * module. @bus should have been added by sfp_bus_add_upstream().
> */
> -void sfp_unregister_upstream(struct sfp_bus *bus)
> +void sfp_bus_del_upstream(struct sfp_bus *bus)
> {
> - rtnl_lock();
> - if (bus->sfp)
> - sfp_unregister_bus(bus);
> - sfp_upstream_clear(bus);
> - rtnl_unlock();
> + if (bus) {
> + rtnl_lock();
> + if (bus->sfp)
> + sfp_unregister_bus(bus);
> + sfp_upstream_clear(bus);
> + rtnl_unlock();
>
> - sfp_bus_put(bus);
> + sfp_bus_put(bus);
> + }
> }
> -EXPORT_SYMBOL_GPL(sfp_unregister_upstream);
> +EXPORT_SYMBOL_GPL(sfp_bus_del_upstream);
>
> /* Socket driver entry points */
> int sfp_add_phy(struct sfp_bus *bus, struct phy_device *phydev)
> diff --git a/include/linux/sfp.h b/include/linux/sfp.h
> index 355a08a76fd4..c8464de7cff5 100644
> --- a/include/linux/sfp.h
> +++ b/include/linux/sfp.h
> @@ -508,10 +508,11 @@ int sfp_get_module_eeprom(struct sfp_bus *bus, struct ethtool_eeprom *ee,
> u8 *data);
> void sfp_upstream_start(struct sfp_bus *bus);
> void sfp_upstream_stop(struct sfp_bus *bus);
> -struct sfp_bus *sfp_register_upstream_node(struct fwnode_handle *fwnode,
> - void *upstream,
> - const struct sfp_upstream_ops *ops);
> -void sfp_unregister_upstream(struct sfp_bus *bus);
> +void sfp_bus_put(struct sfp_bus *bus);
> +struct sfp_bus *sfp_bus_find_fwnode(struct fwnode_handle *fwnode);
> +int sfp_bus_add_upstream(struct sfp_bus *bus, void *upstream,
> + const struct sfp_upstream_ops *ops);
> +void sfp_bus_del_upstream(struct sfp_bus *bus);
> #else
> static inline int sfp_parse_port(struct sfp_bus *bus,
> const struct sfp_eeprom_id *id,
> @@ -553,14 +554,22 @@ static inline void sfp_upstream_stop(struct sfp_bus *bus)
> {
> }
>
> -static inline struct sfp_bus *sfp_register_upstream_node(
> - struct fwnode_handle *fwnode, void *upstream,
> - const struct sfp_upstream_ops *ops)
> +static inline void sfp_bus_put(struct sfp_bus *bus)
> +{
> +}
> +
> +static inline struct sfp_bus *sfp_bus_find_fwnode(struct fwnode_handle *fwnode)
> {
> return NULL;
> }
>
> -static inline void sfp_unregister_upstream(struct sfp_bus *bus)
> +static int sfp_bus_add_upstream(struct sfp_bus *bus, void *upstream,
> + const struct sfp_upstream_ops *ops)
> +{
> + return 0;
> +}
> +
> +static inline void sfp_bus_del_upstream(struct sfp_bus *bus)
> {
> }
> #endif
> --
> 2.20.1
>
>
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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