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of: property: Update implementation of add_links() to create fwnode l…
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…inks

The semantics of add_links() has changed from creating device link
between devices to creating fwnode links between fwnodes. So, update the
implementation of add_links() to match the new semantics.

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20201121020232.908850-15-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Saravana Kannan authored and Greg Kroah-Hartman committed Dec 9, 2020
1 parent 25ac86c commit 8a06d1e
Showing 1 changed file with 41 additions and 109 deletions.
150 changes: 41 additions & 109 deletions drivers/of/property.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1038,33 +1038,9 @@ static bool of_is_ancestor_of(struct device_node *test_ancestor,
}

/**
* of_get_next_parent_dev - Add device link to supplier from supplier phandle
* @np: device tree node
*
* Given a device tree node (@np), this function finds its closest ancestor
* device tree node that has a corresponding struct device.
*
* The caller of this function is expected to call put_device() on the returned
* device when they are done.
*/
static struct device *of_get_next_parent_dev(struct device_node *np)
{
struct device *dev = NULL;

of_node_get(np);
do {
np = of_get_next_parent(np);
if (np)
dev = get_dev_from_fwnode(&np->fwnode);
} while (np && !dev);
of_node_put(np);
return dev;
}

/**
* of_link_to_phandle - Add device link to supplier from supplier phandle
* @dev: consumer device
* @sup_np: phandle to supplier device tree node
* of_link_to_phandle - Add fwnode link to supplier from supplier phandle
* @con_np: consumer device tree node
* @sup_np: supplier device tree node
*
* Given a phandle to a supplier device tree node (@sup_np), this function
* finds the device that owns the supplier device tree node and creates a
Expand All @@ -1074,16 +1050,14 @@ static struct device *of_get_next_parent_dev(struct device_node *np)
* cases, it returns an error.
*
* Returns:
* - 0 if link successfully created to supplier
* - -EAGAIN if linking to the supplier should be reattempted
* - 0 if fwnode link successfully created to supplier
* - -EINVAL if the supplier link is invalid and should not be created
* - -ENODEV if there is no device that corresponds to the supplier phandle
* - -ENODEV if struct device will never be create for supplier
*/
static int of_link_to_phandle(struct device *dev, struct device_node *sup_np,
u32 dl_flags)
static int of_link_to_phandle(struct device_node *con_np,
struct device_node *sup_np)
{
struct device *sup_dev, *sup_par_dev;
int ret = 0;
struct device *sup_dev;
struct device_node *tmp_np = sup_np;

of_node_get(sup_np);
Expand All @@ -1106,7 +1080,8 @@ static int of_link_to_phandle(struct device *dev, struct device_node *sup_np,
}

if (!sup_np) {
dev_dbg(dev, "Not linking to %pOFP - No device\n", tmp_np);
pr_debug("Not linking %pOFP to %pOFP - No device\n",
con_np, tmp_np);
return -ENODEV;
}

Expand All @@ -1115,53 +1090,30 @@ static int of_link_to_phandle(struct device *dev, struct device_node *sup_np,
* descendant nodes. By definition, a child node can't be a functional
* dependency for the parent node.
*/
if (of_is_ancestor_of(dev->of_node, sup_np)) {
dev_dbg(dev, "Not linking to %pOFP - is descendant\n", sup_np);
if (of_is_ancestor_of(con_np, sup_np)) {
pr_debug("Not linking %pOFP to %pOFP - is descendant\n",
con_np, sup_np);
of_node_put(sup_np);
return -EINVAL;
}

/*
* Don't create links to "early devices" that won't have struct devices
* created for them.
*/
sup_dev = get_dev_from_fwnode(&sup_np->fwnode);
if (!sup_dev && of_node_check_flag(sup_np, OF_POPULATED)) {
/* Early device without struct device. */
dev_dbg(dev, "Not linking to %pOFP - No struct device\n",
sup_np);
pr_debug("Not linking %pOFP to %pOFP - No struct device\n",
con_np, sup_np);
of_node_put(sup_np);
return -ENODEV;
} else if (!sup_dev) {
/*
* DL_FLAG_SYNC_STATE_ONLY doesn't block probing and supports
* cycles. So cycle detection isn't necessary and shouldn't be
* done.
*/
if (dl_flags & DL_FLAG_SYNC_STATE_ONLY) {
of_node_put(sup_np);
return -EAGAIN;
}

sup_par_dev = of_get_next_parent_dev(sup_np);

if (sup_par_dev && device_is_dependent(dev, sup_par_dev)) {
/* Cyclic dependency detected, don't try to link */
dev_dbg(dev, "Not linking to %pOFP - cycle detected\n",
sup_np);
ret = -EINVAL;
} else {
/*
* Can't check for cycles or no cycles. So let's try
* again later.
*/
ret = -EAGAIN;
}

of_node_put(sup_np);
put_device(sup_par_dev);
return ret;
}
of_node_put(sup_np);
if (!device_link_add(dev, sup_dev, dl_flags))
ret = -EINVAL;
put_device(sup_dev);
return ret;

fwnode_link_add(of_fwnode_handle(con_np), of_fwnode_handle(sup_np));
of_node_put(sup_np);

return 0;
}

/**
Expand Down Expand Up @@ -1361,69 +1313,49 @@ static const struct supplier_bindings of_supplier_bindings[] = {
* that list phandles to suppliers. If @prop_name isn't one, this function
* doesn't do anything.
*
* If @prop_name is one, this function attempts to create device links from the
* consumer device @dev to all the devices of the suppliers listed in
* @prop_name.
* If @prop_name is one, this function attempts to create fwnode links from the
* consumer device tree node @con_np to all the suppliers device tree nodes
* listed in @prop_name.
*
* Any failed attempt to create a device link will NOT result in an immediate
* Any failed attempt to create a fwnode link will NOT result in an immediate
* return. of_link_property() must create links to all the available supplier
* devices even when attempts to create a link to one or more suppliers fail.
* device tree nodes even when attempts to create a link to one or more
* suppliers fail.
*/
static int of_link_property(struct device *dev, struct device_node *con_np,
const char *prop_name)
static int of_link_property(struct device_node *con_np, const char *prop_name)
{
struct device_node *phandle;
const struct supplier_bindings *s = of_supplier_bindings;
unsigned int i = 0;
bool matched = false;
int ret = 0;
u32 dl_flags;

if (dev->of_node == con_np)
dl_flags = fw_devlink_get_flags();
else
dl_flags = DL_FLAG_SYNC_STATE_ONLY;

/* Do not stop at first failed link, link all available suppliers. */
while (!matched && s->parse_prop) {
while ((phandle = s->parse_prop(con_np, prop_name, i))) {
matched = true;
i++;
if (of_link_to_phandle(dev, phandle, dl_flags)
== -EAGAIN)
ret = -EAGAIN;
of_link_to_phandle(con_np, phandle);
of_node_put(phandle);
}
s++;
}
return ret;
}

static int of_link_to_suppliers(struct device *dev,
struct device_node *con_np)
static int of_fwnode_add_links(struct fwnode_handle *fwnode,
struct device *dev)
{
struct device_node *child;
struct property *p;
int ret = 0;
struct device_node *con_np = to_of_node(fwnode);

for_each_property_of_node(con_np, p)
if (of_link_property(dev, con_np, p->name))
ret = -ENODEV;

for_each_available_child_of_node(con_np, child)
if (of_link_to_suppliers(dev, child) && !ret)
ret = -EAGAIN;

return ret;
}
if (!con_np)
return -EINVAL;

static int of_fwnode_add_links(const struct fwnode_handle *fwnode,
struct device *dev)
{
if (unlikely(!is_of_node(fwnode)))
return 0;
for_each_property_of_node(con_np, p)
of_link_property(con_np, p->name);

return of_link_to_suppliers(dev, to_of_node(fwnode));
return 0;
}

const struct fwnode_operations of_fwnode_ops = {
Expand Down

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