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net: sfp: rework upstream interface
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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@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Russell King authored and David S. Miller committed Nov 10, 2019
1 parent 14684b9 commit 727b366
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Showing 3 changed files with 88 additions and 39 deletions.
10 changes: 6 additions & 4 deletions drivers/net/phy/phylink.c
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Original file line number Diff line number Diff line change
Expand Up @@ -567,7 +567,7 @@ 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);
Expand All @@ -576,7 +576,10 @@ 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;
}

/**
Expand Down Expand Up @@ -670,8 +673,7 @@ 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);

Expand Down
92 changes: 65 additions & 27 deletions drivers/net/phy/sfp-bus.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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)
{
Expand All @@ -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;
}

Expand Down Expand Up @@ -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,
Expand All @@ -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;
Expand All @@ -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;

Expand All @@ -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)
Expand Down
25 changes: 17 additions & 8 deletions include/linux/sfp.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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,
Expand Down Expand Up @@ -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
Expand Down

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