diff options
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 5 | ||||
| -rw-r--r-- | drivers/of/platform.c | 165 |
2 files changed, 170 insertions, 0 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 46b826fcb5ad..12937349d79d 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -3170,6 +3170,11 @@ This can be set from sysctl after boot. See Documentation/admin-guide/sysctl/vm.rst for details. + of_devlink [KNL] Make device links from common DT bindings. Useful + for optimizing probe order and making sure resources + aren't turned off before the consumer devices have + probed. + ohci1394_dma=early [HW] enable debugging via the ohci1394 driver. See Documentation/debugging-via-ohci1394.txt for more info. diff --git a/drivers/of/platform.c b/drivers/of/platform.c index b47a2292fe8e..c1c433333124 100644 --- a/drivers/of/platform.c +++ b/drivers/of/platform.c @@ -503,6 +503,170 @@ int of_platform_default_populate(struct device_node *root, } EXPORT_SYMBOL_GPL(of_platform_default_populate); +bool of_link_is_valid(struct device_node *con, struct device_node *sup) +{ + of_node_get(sup); + /* + * 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. + */ + while (sup) { + if (sup == con) { + of_node_put(sup); + return false; + } + sup = of_get_next_parent(sup); + } + return true; +} + +static int of_link_to_phandle(struct device *dev, struct device_node *sup_np) +{ + struct platform_device *sup_dev; + u32 dl_flags = DL_FLAG_AUTOPROBE_CONSUMER; + int ret = 0; + + /* + * Since we are trying to create device links, we need to find + * the actual device node that owns this supplier phandle. + * Often times it's the same node, but sometimes it can be one + * of the parents. So walk up the parent till you find a + * device. + */ + while (sup_np && !of_find_property(sup_np, "compatible", NULL)) + sup_np = of_get_next_parent(sup_np); + if (!sup_np) + return 0; + + if (!of_link_is_valid(dev->of_node, sup_np)) { + of_node_put(sup_np); + return 0; + } + sup_dev = of_find_device_by_node(sup_np); + of_node_put(sup_np); + if (!sup_dev) + return -ENODEV; + if (!device_link_add(dev, &sup_dev->dev, dl_flags)) + ret = -ENODEV; + put_device(&sup_dev->dev); + return ret; +} + +static struct device_node *parse_prop_cells(struct device_node *np, + const char *prop, int index, + const char *binding, + const char *cell) +{ + struct of_phandle_args sup_args; + + /* Don't need to check property name for every index. */ + if (!index && strcmp(prop, binding)) + return NULL; + + if (of_parse_phandle_with_args(np, binding, cell, index, &sup_args)) + return NULL; + + return sup_args.np; +} + +static struct device_node *parse_clocks(struct device_node *np, + const char *prop, int index) +{ + return parse_prop_cells(np, prop, index, "clocks", "#clock-cells"); +} + +static struct device_node *parse_interconnects(struct device_node *np, + const char *prop, int index) +{ + return parse_prop_cells(np, prop, index, "interconnects", + "#interconnect-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); +} + +static struct device_node *parse_regulators(struct device_node *np, + const char *prop, int index) +{ + if (index || strcmp_suffix(prop, "-supply")) + return NULL; + + return of_parse_phandle(np, prop, 0); +} + +/** + * struct supplier_bindings - Information for parsing supplier DT binding + * + * @parse_prop: If the function cannot parse the property, return NULL. + * Otherwise, return the phandle listed in the property + * that corresponds to the index. + */ +struct supplier_bindings { + struct device_node *(*parse_prop)(struct device_node *np, + const char *name, int index); +}; + +static const struct supplier_bindings bindings[] = { + { .parse_prop = parse_clocks, }, + { .parse_prop = parse_interconnects, }, + { .parse_prop = parse_regulators, }, + { }, +}; + +static bool of_link_property(struct device *dev, struct device_node *con_np, + const char *prop) +{ + struct device_node *phandle; + const struct supplier_bindings *s = bindings; + unsigned int i = 0; + bool done = true, matched = false; + + while (!matched && s->parse_prop) { + while ((phandle = s->parse_prop(con_np, prop, i))) { + matched = true; + i++; + if (of_link_to_phandle(dev, phandle)) + /* + * Don't stop at the first failure. See + * Documentation for bus_type.add_links for + * more details. + */ + done = false; + } + s++; + } + return done ? 0 : -ENODEV; +} + +static bool of_devlink; +core_param(of_devlink, of_devlink, bool, 0); + +static int of_link_to_suppliers(struct device *dev) +{ + struct property *p; + bool done = true; + + if (!of_devlink) + return 0; + if (unlikely(!dev->of_node)) + return 0; + + for_each_property_of_node(dev->of_node, p) + if (of_link_property(dev, dev->of_node, p->name)) + done = false; + + return done ? 0 : -ENODEV; +} + #ifndef CONFIG_PPC static const struct of_device_id reserved_mem_matches[] = { { .compatible = "qcom,rmtfs-mem" }, @@ -518,6 +682,7 @@ static int __init of_platform_default_populate_init(void) if (!of_have_populated_dt()) return -ENODEV; + platform_bus_type.add_links = of_link_to_suppliers; /* * Handle certain compatibles explicitly, since we don't want to create * platform_devices for every node in /reserved-memory with a |