[PATCH 08/11] of: platform: provide of_early_platform_populate()

From: Bartosz Golaszewski
Date: Tue Apr 24 2018 - 13:32:34 EST

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From: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>

Implement a variant of of_platform_populate() which scans child nodes
of the root device node for the "earlydev" compatible fallback and
registers the corresponding platform devices as early platform devices.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
---
drivers/of/device.c | 14 +++++-
drivers/of/platform.c | 89 +++++++++++++++++++++++++++++++------
include/linux/of_device.h | 5 +++
include/linux/of_platform.h | 17 +++++++
4 files changed, 110 insertions(+), 15 deletions(-)

diff --git a/drivers/of/device.c b/drivers/of/device.c
index 064c818105bd..cef13538d539 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -53,7 +53,7 @@ void of_dev_put(struct platform_device *dev)
}
EXPORT_SYMBOL(of_dev_put);

-int of_device_add(struct platform_device *ofdev)
+static void of_device_add_prepare(struct platform_device *ofdev)
{
BUG_ON(ofdev->dev.of_node == NULL);

@@ -68,10 +68,22 @@ int of_device_add(struct platform_device *ofdev)
* device is on the same node as the parent.
*/
set_dev_node(&ofdev->dev, of_node_to_nid(ofdev->dev.of_node));
+}

+int of_device_add(struct platform_device *ofdev)
+{
+ of_device_add_prepare(ofdev);
return device_add(&ofdev->dev);
}

+#ifdef CONFIG_EARLY_PLATFORM_DEVICES
+void of_device_add_early(struct platform_device *ofdev)
+{
+ of_device_add_prepare(ofdev);
+ early_platform_add_device(ofdev);
+}
+#endif /* CONFIG_EARLY_PLATFORM_DEVICES */
+
/**
* of_dma_configure - Setup DMA configuration
* @dev: Device to apply DMA configuration
diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 60342209fbd8..4b55e568fe77 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -160,6 +160,7 @@ EXPORT_SYMBOL(of_device_alloc);
* @bus_id: name to assign device
* @platform_data: pointer to populate platform_data pointer with
* @parent: Linux device model parent device.
+ * @early: create as an early platform device
*
* Returns pointer to created platform device, or NULL if a device was not
* registered. Unavailable devices will not get registered.
@@ -168,9 +169,11 @@ static struct platform_device *of_platform_device_create_pdata(
struct device_node *np,
const char *bus_id,
void *platform_data,
- struct device *parent)
+ struct device *parent,
+ bool early)
{
struct platform_device *pdev;
+ int rc;

if (!of_device_is_available(np) ||
of_node_test_and_set_flag(np, OF_POPULATED))
@@ -184,9 +187,14 @@ static struct platform_device *of_platform_device_create_pdata(
pdev->dev.platform_data = platform_data;
of_msi_configure(&pdev->dev, pdev->dev.of_node);

- if (of_device_add(pdev) != 0) {
- platform_device_put(pdev);
- goto err_clear_flag;
+ if (unlikely(early)) {
+ of_device_add_early(pdev);
+ } else {
+ rc = of_device_add(pdev);
+ if (rc) {
+ platform_device_put(pdev);
+ goto err_clear_flag;
+ }
}

return pdev;
@@ -209,7 +217,7 @@ struct platform_device *of_platform_device_create(struct device_node *np,
const char *bus_id,
struct device *parent)
{
- return of_platform_device_create_pdata(np, bus_id, NULL, parent);
+ return of_platform_device_create_pdata(np, bus_id, NULL, parent, false);
}
EXPORT_SYMBOL(of_platform_device_create);

@@ -333,6 +341,7 @@ static const struct of_dev_auxdata *of_dev_lookup(const struct of_dev_auxdata *l
* @lookup: auxdata table for matching id and platform_data with device nodes
* @parent: parent for new device, or NULL for top level.
* @strict: require compatible property
+ * @early: register sub-devices as early platform devices
*
* Creates a platform_device for the provided device_node, and optionally
* recursively create devices for all the child nodes.
@@ -340,7 +349,8 @@ static const struct of_dev_auxdata *of_dev_lookup(const struct of_dev_auxdata *l
static int of_platform_bus_create(struct device_node *bus,
const struct of_device_id *matches,
const struct of_dev_auxdata *lookup,
- struct device *parent, bool strict)
+ struct device *parent,
+ bool strict, bool early)
{
const struct of_dev_auxdata *auxdata;
struct device_node *child;
@@ -377,13 +387,15 @@ static int of_platform_bus_create(struct device_node *bus,
return 0;
}

- pdev = of_platform_device_create_pdata(bus, bus_id, platform_data, parent);
+ pdev = of_platform_device_create_pdata(bus, bus_id,
+ platform_data, parent, early);
if (!pdev || !of_match_node(matches, bus))
return 0;

for_each_child_of_node(bus, child) {
pr_debug(" create child: %pOF\n", child);
- rc = of_platform_bus_create(child, matches, lookup, &pdev->dev, strict);
+ rc = of_platform_bus_create(child, matches, lookup,
+ &pdev->dev, strict, early);
if (rc) {
of_node_put(child);
break;
@@ -418,11 +430,13 @@ int of_platform_bus_probe(struct device_node *root,

/* Do a self check of bus type, if there's a match, create children */
if (of_match_node(matches, root)) {
- rc = of_platform_bus_create(root, matches, NULL, parent, false);
+ rc = of_platform_bus_create(root, matches, NULL,
+ parent, false, false);
} else for_each_child_of_node(root, child) {
if (!of_match_node(matches, child))
continue;
- rc = of_platform_bus_create(child, matches, NULL, parent, false);
+ rc = of_platform_bus_create(child, matches, NULL,
+ parent, false, false);
if (rc) {
of_node_put(child);
break;
@@ -454,9 +468,9 @@ EXPORT_SYMBOL(of_platform_bus_probe);
* Returns 0 on success, < 0 on failure.
*/
int of_platform_populate(struct device_node *root,
- const struct of_device_id *matches,
- const struct of_dev_auxdata *lookup,
- struct device *parent)
+ const struct of_device_id *matches,
+ const struct of_dev_auxdata *lookup,
+ struct device *parent)
{
struct device_node *child;
int rc = 0;
@@ -469,7 +483,8 @@ int of_platform_populate(struct device_node *root,
pr_debug(" starting at: %pOF\n", root);

for_each_child_of_node(root, child) {
- rc = of_platform_bus_create(child, matches, lookup, parent, true);
+ rc = of_platform_bus_create(child, matches, lookup,
+ parent, false, false);
if (rc) {
of_node_put(child);
break;
@@ -482,6 +497,52 @@ int of_platform_populate(struct device_node *root,
}
EXPORT_SYMBOL_GPL(of_platform_populate);

+/**
+ * of_early_platform_populate() - Populate platform_devices from device tree
+ * data early in the boot process
+ * @root: parent of the first level to probe or NULL for the root of the tree
+ * @matches: match table, NULL to use the default
+ * @lookup: auxdata table for matching id and platform_data with device nodes
+ * @parent: parent to hook devices from, NULL for toplevel
+ *
+ * Virtually the same as of_platform_populate() except that it adds devices
+ * as early platform devices.
+ *
+ * Returns 0 on success, < 0 on failure.
+ */
+#ifdef CONFIG_EARLY_PLATFORM_DEVICES
+int of_early_platform_populate(struct device_node *root,
+ const struct of_device_id *matches,
+ const struct of_dev_auxdata *lookup,
+ struct device *parent)
+{
+ struct device_node *child;
+ int rc = 0;
+
+ root = root ? of_node_get(root) : of_find_node_by_path("/");
+ if (!root)
+ return -EINVAL;
+
+ pr_debug("%s()\n", __func__);
+ pr_debug(" starting at: %pOF\n", root);
+
+ for_each_compatible_child_node(child, NULL,
+ EARLY_PLATFORM_DEFAULT_CLASS, root) {
+ rc = of_platform_bus_create(child, matches, lookup,
+ parent, false, true);
+ if (rc) {
+ of_node_put(child);
+ break;
+ }
+ }
+ of_node_set_flag(root, OF_POPULATED_BUS);
+
+ of_node_put(root);
+ return rc;
+}
+EXPORT_SYMBOL_GPL(of_early_platform_populate);
+#endif /* CONFIG_EARLY_PLATFORM_DEVICES */
+
int of_platform_default_populate(struct device_node *root,
const struct of_dev_auxdata *lookup,
struct device *parent)
diff --git a/include/linux/of_device.h b/include/linux/of_device.h
index 8da5a1b31ece..8a59a054a434 100644
--- a/include/linux/of_device.h
+++ b/include/linux/of_device.h
@@ -30,6 +30,11 @@ extern struct platform_device *of_dev_get(struct platform_device *dev);
extern void of_dev_put(struct platform_device *dev);

extern int of_device_add(struct platform_device *pdev);
+#ifdef CONFIG_EARLY_PLATFORM_DEVICES
+extern void of_device_add_early(struct platform_device *pdev);
+#else /* CONFIG_EARLY_PLATFORM_DEVICES */
+static inline void of_device_add_early(struct platform_device *pdev) {}
+#endif /* CONFIG_EARLY_PLATFORM_DEVICES */
extern int of_device_register(struct platform_device *ofdev);
extern void of_device_unregister(struct platform_device *ofdev);

diff --git a/include/linux/of_platform.h b/include/linux/of_platform.h
index 84a966623e78..2bf1013a3e89 100644
--- a/include/linux/of_platform.h
+++ b/include/linux/of_platform.h
@@ -75,6 +75,23 @@ extern int of_platform_populate(struct device_node *root,
const struct of_device_id *matches,
const struct of_dev_auxdata *lookup,
struct device *parent);
+
+#ifdef CONFIG_EARLY_PLATFORM_DEVICES
+extern int of_early_platform_populate(struct device_node *root,
+ const struct of_device_id *matches,
+ const struct of_dev_auxdata *lookup,
+ struct device *parent);
+#else /* CONFIG_EARLY_PLATFORM_DEVICES */
+static inline int
+of_early_platform_populate(struct device_node *root,
+ const struct of_device_id *matches,
+ const struct of_dev_auxdata *lookup,
+ struct device *parent)
+{
+ return -ENOSYS;
+}
+#endif /* CONFIG_EARLY_PLATFORM_DEVICES */
+
extern int of_platform_default_populate(struct device_node *root,
const struct of_dev_auxdata *lookup,
struct device *parent);
--
2.17.0

Next message: Bartosz Golaszewski: "[PATCH 09/11] platform: provide early_platform_driver()"
Previous message: Bart Van Assche: "Re: Regression 4.17-rc1: SSD doesn properly resume causing system hang (NULL pointer dereference)"
In reply to: Bartosz Golaszewski: "[PATCH 11/11] misc: implement a dummy early platform driver"
Next in thread: Bartosz Golaszewski: "[PATCH 09/11] platform: provide early_platform_driver()"
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