Merge tag 'driver-core-5.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core updates from Greg KH:
 "Here is the "big" set of driver core patches for 5.5-rc1

  There's a few minor cleanups and fixes in here, but the majority of
  the patches in here fall into two buckets:

   - debugfs api cleanups and fixes

   - driver core device link support for boot dependancy issues

  The debugfs api cleanups are working to slowly refactor the debugfs
  apis so that it is even harder to use incorrectly. That work has been
  happening for the past few kernel releases and will continue over
  time, it's a long-term project/goal

  The driver core device link support missed 5.4 by just a bit, so it's
  been sitting and baking for many months now. It's from Saravana Kannan
  to help resolve the problems that DT-based systems have at boot time
  with dependancy graphs and kernel modules. Turns out that no one has
  actually tried to build a generic arm64 kernel with loads of modules
  and have it "just work" for a variety of platforms (like a distro
  kernel). The big problem turned out to be a lack of dependency
  information between different areas of DT entries, and the work here
  resolves that problem and now allows devices to boot properly, and
  quicker than a monolith kernel.

  All of these patches have been in linux-next for a long time with no
  reported issues"

* tag 'driver-core-5.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (68 commits)
  tracing: Remove unnecessary DEBUG_FS dependency
  of: property: Add device link support for interrupt-parent, dmas and -gpio(s)
  debugfs: Fix !DEBUG_FS debugfs_create_automount
  of: property: Add device link support for "iommu-map"
  of: property: Fix the semantics of of_is_ancestor_of()
  i2c: of: Populate fwnode in of_i2c_get_board_info()
  drivers: base: Fix Kconfig indentation
  firmware_loader: Fix labels with comma for builtin firmware
  driver core: Allow device link operations inside sync_state()
  driver core: platform: Declare ret variable only once
  cpu-topology: declare parse_acpi_topology in <linux/arch_topology.h>
  crypto: hisilicon: no need to check return value of debugfs_create functions
  driver core: platform: use the correct callback type for bus_find_device
  firmware_class: make firmware caching configurable
  driver core: Clarify documentation for fwnode_operations.add_links()
  mailbox: tegra: Fix superfluous IRQ error message
  net: caif: Fix debugfs on 64-bit platforms
  mac80211: Use debugfs_create_xul() helper
  media: c8sectpfe: no need to check return value of debugfs_create functions
  of: property: Add device link support for iommus, mboxes and io-channels
  ...

2 files changed, 328 insertions, 0 deletions

diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index b47a2292fe8e..d93891a05f60 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -480,6 +480,7 @@ int of_platform_populate(struct device_node *root,
 	pr_debug("%s()\n", __func__);
 	pr_debug(" starting at: %pOF\n", root);
 
+	device_links_supplier_sync_state_pause();
 	for_each_child_of_node(root, child) {
 		rc = of_platform_bus_create(child, matches, lookup, parent, true);
 		if (rc) {
@@ -487,6 +488,8 @@ int of_platform_populate(struct device_node *root,
 			break;
 		}
 	}
+	device_links_supplier_sync_state_resume();
+
 	of_node_set_flag(root, OF_POPULATED_BUS);
 
 	of_node_put(root);
@@ -518,6 +521,7 @@ static int __init of_platform_default_populate_init(void)
 	if (!of_have_populated_dt())
 		return -ENODEV;
 
+	device_links_supplier_sync_state_pause();
 	/*
 	 * Handle certain compatibles explicitly, since we don't want to create
 	 * platform_devices for every node in /reserved-memory with a
@@ -538,6 +542,14 @@ static int __init of_platform_default_populate_init(void)
 	return 0;
 }
 arch_initcall_sync(of_platform_default_populate_init);
+
+static int __init of_platform_sync_state_init(void)
+{
+	if (of_have_populated_dt())
+		device_links_supplier_sync_state_resume();
+	return 0;
+}
+late_initcall_sync(of_platform_sync_state_init);
 #endif
 
 int of_platform_device_destroy(struct device *dev, void *data)
diff --git a/drivers/of/property.c b/drivers/of/property.c
index e8202f61a5d9..477966d2421a 100644
--- a/drivers/of/property.c
+++ b/drivers/of/property.c
@@ -25,6 +25,7 @@
 #include <linux/of_device.h>
 #include <linux/of_graph.h>
 #include <linux/string.h>
+#include <linux/moduleparam.h>
 
 #include "of_private.h"
 
@@ -999,6 +1000,320 @@ of_fwnode_device_get_match_data(const struct fwnode_handle *fwnode,
 	return of_device_get_match_data(dev);
 }
 
+static bool of_is_ancestor_of(struct device_node *test_ancestor,
+			      struct device_node *child)
+{
+	of_node_get(child);
+	while (child) {
+		if (child == test_ancestor) {
+			of_node_put(child);
+			return true;
+		}
+		child = of_get_next_parent(child);
+	}
+	return false;
+}
+
+/**
+ * of_link_to_phandle - Add device link to supplier from supplier phandle
+ * @dev: consumer device
+ * @sup_np: phandle to 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
+ * device link from @dev consumer device to the supplier device. This function
+ * doesn't create device links for invalid scenarios such as trying to create a
+ * link with a parent device as the consumer of its child device. In such
+ * cases, it returns an error.
+ *
+ * Returns:
+ * - 0 if link successfully created to supplier
+ * - -EAGAIN if linking to the supplier should be reattempted
+ * - -EINVAL if the supplier link is invalid and should not be created
+ * - -ENODEV if there is no device that corresponds to the supplier phandle
+ */
+static int of_link_to_phandle(struct device *dev, struct device_node *sup_np,
+			      u32 dl_flags)
+{
+	struct device *sup_dev;
+	int ret = 0;
+	struct device_node *tmp_np = sup_np;
+	int is_populated;
+
+	of_node_get(sup_np);
+	/*
+	 * Find the device node that contains the supplier phandle.  It may be
+	 * @sup_np or it may be an ancestor of @sup_np.
+	 */
+	while (sup_np && !of_find_property(sup_np, "compatible", NULL))
+		sup_np = of_get_next_parent(sup_np);
+	if (!sup_np) {
+		dev_dbg(dev, "Not linking to %pOFP - No device\n", tmp_np);
+		return -ENODEV;
+	}
+
+	/*
+	 * Don't allow linking a device node as a consumer of one of its
+	 * 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);
+		of_node_put(sup_np);
+		return -EINVAL;
+	}
+	sup_dev = get_dev_from_fwnode(&sup_np->fwnode);
+	is_populated = of_node_check_flag(sup_np, OF_POPULATED);
+	of_node_put(sup_np);
+	if (!sup_dev && is_populated) {
+		/* Early device without struct device. */
+		dev_dbg(dev, "Not linking to %pOFP - No struct device\n",
+			sup_np);
+		return -ENODEV;
+	} else if (!sup_dev) {
+		return -EAGAIN;
+	}
+	if (!device_link_add(dev, sup_dev, dl_flags))
+		ret = -EAGAIN;
+	put_device(sup_dev);
+	return ret;
+}
+
+/**
+ * parse_prop_cells - Property parsing function for suppliers
+ *
+ * @np:		Pointer to device tree node containing a list
+ * @prop_name:	Name of property to be parsed. Expected to hold phandle values
+ * @index:	For properties holding a list of phandles, this is the index
+ *		into the list.
+ * @list_name:	Property name that is known to contain list of phandle(s) to
+ *		supplier(s)
+ * @cells_name:	property name that specifies phandles' arguments count
+ *
+ * This is a helper function to parse properties that have a known fixed name
+ * and are a list of phandles and phandle arguments.
+ *
+ * Returns:
+ * - phandle node pointer with refcount incremented. Caller must of_node_put()
+ *   on it when done.
+ * - NULL if no phandle found at index
+ */
+static struct device_node *parse_prop_cells(struct device_node *np,
+					    const char *prop_name, int index,
+					    const char *list_name,
+					    const char *cells_name)
+{
+	struct of_phandle_args sup_args;
+
+	if (strcmp(prop_name, list_name))
+		return NULL;
+
+	if (of_parse_phandle_with_args(np, list_name, cells_name, index,
+				       &sup_args))
+		return NULL;
+
+	return sup_args.np;
+}
+
+#define DEFINE_SIMPLE_PROP(fname, name, cells)				  \
+static struct device_node *parse_##fname(struct device_node *np,	  \
+					const char *prop_name, int index) \
+{									  \
+	return parse_prop_cells(np, prop_name, index, name, cells);	  \
+}
+
+static int strcmp_suffix(const char *str, const char *suffix)
+{
+	unsigned int len, suffix_len;
+
+	len = strlen(str);
+	suffix_len = strlen(suffix);
+	if (len <= suffix_len)
+		return -1;
+	return strcmp(str + len - suffix_len, suffix);
+}
+
+/**
+ * parse_suffix_prop_cells - Suffix property parsing function for suppliers
+ *
+ * @np:		Pointer to device tree node containing a list
+ * @prop_name:	Name of property to be parsed. Expected to hold phandle values
+ * @index:	For properties holding a list of phandles, this is the index
+ *		into the list.
+ * @suffix:	Property suffix that is known to contain list of phandle(s) to
+ *		supplier(s)
+ * @cells_name:	property name that specifies phandles' arguments count
+ *
+ * This is a helper function to parse properties that have a known fixed suffix
+ * and are a list of phandles and phandle arguments.
+ *
+ * Returns:
+ * - phandle node pointer with refcount incremented. Caller must of_node_put()
+ *   on it when done.
+ * - NULL if no phandle found at index
+ */
+static struct device_node *parse_suffix_prop_cells(struct device_node *np,
+					    const char *prop_name, int index,
+					    const char *suffix,
+					    const char *cells_name)
+{
+	struct of_phandle_args sup_args;
+
+	if (strcmp_suffix(prop_name, suffix))
+		return NULL;
+
+	if (of_parse_phandle_with_args(np, prop_name, cells_name, index,
+				       &sup_args))
+		return NULL;
+
+	return sup_args.np;
+}
+
+#define DEFINE_SUFFIX_PROP(fname, suffix, cells)			     \
+static struct device_node *parse_##fname(struct device_node *np,	     \
+					const char *prop_name, int index)    \
+{									     \
+	return parse_suffix_prop_cells(np, prop_name, index, suffix, cells); \
+}
+
+/**
+ * struct supplier_bindings - Property parsing functions for suppliers
+ *
+ * @parse_prop: function name
+ *	parse_prop() finds the node corresponding to a supplier phandle
+ * @parse_prop.np: Pointer to device node holding supplier phandle property
+ * @parse_prop.prop_name: Name of property holding a phandle value
+ * @parse_prop.index: For properties holding a list of phandles, this is the
+ *		      index into the list
+ *
+ * Returns:
+ * parse_prop() return values are
+ * - phandle node pointer with refcount incremented. Caller must of_node_put()
+ *   on it when done.
+ * - NULL if no phandle found at index
+ */
+struct supplier_bindings {
+	struct device_node *(*parse_prop)(struct device_node *np,
+					  const char *prop_name, int index);
+};
+
+DEFINE_SIMPLE_PROP(clocks, "clocks", "#clock-cells")
+DEFINE_SIMPLE_PROP(interconnects, "interconnects", "#interconnect-cells")
+DEFINE_SIMPLE_PROP(iommus, "iommus", "#iommu-cells")
+DEFINE_SIMPLE_PROP(mboxes, "mboxes", "#mbox-cells")
+DEFINE_SIMPLE_PROP(io_channels, "io-channel", "#io-channel-cells")
+DEFINE_SIMPLE_PROP(interrupt_parent, "interrupt-parent", NULL)
+DEFINE_SIMPLE_PROP(dmas, "dmas", "#dma-cells")
+DEFINE_SUFFIX_PROP(regulators, "-supply", NULL)
+DEFINE_SUFFIX_PROP(gpio, "-gpio", "#gpio-cells")
+DEFINE_SUFFIX_PROP(gpios, "-gpios", "#gpio-cells")
+
+static struct device_node *parse_iommu_maps(struct device_node *np,
+					    const char *prop_name, int index)
+{
+	if (strcmp(prop_name, "iommu-map"))
+		return NULL;
+
+	return of_parse_phandle(np, prop_name, (index * 4) + 1);
+}
+
+static const struct supplier_bindings of_supplier_bindings[] = {
+	{ .parse_prop = parse_clocks, },
+	{ .parse_prop = parse_interconnects, },
+	{ .parse_prop = parse_iommus, },
+	{ .parse_prop = parse_iommu_maps, },
+	{ .parse_prop = parse_mboxes, },
+	{ .parse_prop = parse_io_channels, },
+	{ .parse_prop = parse_interrupt_parent, },
+	{ .parse_prop = parse_dmas, },
+	{ .parse_prop = parse_regulators, },
+	{ .parse_prop = parse_gpio, },
+	{ .parse_prop = parse_gpios, },
+	{}
+};
+
+/**
+ * of_link_property - Create device links to suppliers listed in a property
+ * @dev: Consumer device
+ * @con_np: The consumer device tree node which contains the property
+ * @prop_name: Name of property to be parsed
+ *
+ * This function checks if the property @prop_name that is present in the
+ * @con_np device tree node is one of the known common device tree 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.
+ *
+ * Any failed attempt to create a device 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.
+ */
+static int of_link_property(struct device *dev, 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 = DL_FLAG_AUTOPROBE_CONSUMER;
+	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_node_put(phandle);
+		}
+		s++;
+	}
+	return ret;
+}
+
+static int of_link_to_suppliers(struct device *dev,
+				  struct device_node *con_np)
+{
+	struct device_node *child;
+	struct property *p;
+	int ret = 0;
+
+	for_each_property_of_node(con_np, p)
+		if (of_link_property(dev, con_np, p->name))
+			ret = -ENODEV;
+
+	for_each_child_of_node(con_np, child)
+		if (of_link_to_suppliers(dev, child) && !ret)
+			ret = -EAGAIN;
+
+	return ret;
+}
+
+static bool of_devlink;
+core_param(of_devlink, of_devlink, bool, 0);
+
+static int of_fwnode_add_links(const struct fwnode_handle *fwnode,
+			       struct device *dev)
+{
+	if (!of_devlink)
+		return 0;
+
+	if (unlikely(!is_of_node(fwnode)))
+		return 0;
+
+	return of_link_to_suppliers(dev, to_of_node(fwnode));
+}
+
 const struct fwnode_operations of_fwnode_ops = {
 	.get = of_fwnode_get,
 	.put = of_fwnode_put,
@@ -1017,5 +1332,6 @@ const struct fwnode_operations of_fwnode_ops = {
 	.graph_get_remote_endpoint = of_fwnode_graph_get_remote_endpoint,
 	.graph_get_port_parent = of_fwnode_graph_get_port_parent,
 	.graph_parse_endpoint = of_fwnode_graph_parse_endpoint,
+	.add_links = of_fwnode_add_links,
 };
 EXPORT_SYMBOL_GPL(of_fwnode_ops);