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Subject[PATCH v4 5/8] driver core: fw_devlink: Handle suppliers that don't use driver core
From
Device links only work between devices that use the driver core to match
and bind a driver to a device. So, add an API for frameworks to let the
driver core know that a fwnode has been initialized by a driver without
using the driver core.

Then use this information to make sure that fw_devlink doesn't make the
consumers wait indefinitely on suppliers that'll never bind to a driver.

Signed-off-by: Saravana Kannan <saravanak@google.com>
---
drivers/base/core.c | 15 +++++++++++++++
include/linux/fwnode.h | 19 +++++++++++++++++--
2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index f466ab4f1c35..ea710b33bda6 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -1636,6 +1636,17 @@ static int fw_devlink_create_devlink(struct device *con,

sup_dev = get_dev_from_fwnode(sup_handle);
if (sup_dev) {
+ /*
+ * If it's one of those drivers that don't actually bind to
+ * their device using driver core, then don't wait on this
+ * supplier device indefinitely.
+ */
+ if (sup_dev->links.status == DL_DEV_NO_DRIVER &&
+ sup_handle->flags & FWNODE_FLAG_INITIALIZED) {
+ ret = -EINVAL;
+ goto out;
+ }
+
/*
* If this fails, it is due to cycles in device links. Just
* give up on this link and treat it as invalid.
@@ -1655,6 +1666,10 @@ static int fw_devlink_create_devlink(struct device *con,
goto out;
}

+ /* Supplier that's already initialized without a struct device. */
+ if (sup_handle->flags & FWNODE_FLAG_INITIALIZED)
+ return -EINVAL;
+
/*
* DL_FLAG_SYNC_STATE_ONLY doesn't block probing and supports
* cycles. So cycle detection isn't necessary and shouldn't be
diff --git a/include/linux/fwnode.h b/include/linux/fwnode.h
index d5caefe39d93..dfefd43a737c 100644
--- a/include/linux/fwnode.h
+++ b/include/linux/fwnode.h
@@ -11,6 +11,7 @@

#include <linux/types.h>
#include <linux/list.h>
+#include <linux/err.h>

struct fwnode_operations;
struct device;
@@ -18,11 +19,13 @@ struct device;
/*
* fwnode link flags
*
- * LINKS_ADDED: The fwnode has already be parsed to add fwnode links.
- * NOT_DEVICE: The fwnode will never be populated as a struct device.
+ * LINKS_ADDED: The fwnode has already be parsed to add fwnode links.
+ * NOT_DEVICE: The fwnode will never be populated as a struct device.
+ * INITIALIZED: The hardware corresponding to fwnode has been initialized.
*/
#define FWNODE_FLAG_LINKS_ADDED BIT(0)
#define FWNODE_FLAG_NOT_DEVICE BIT(1)
+#define FWNODE_FLAG_INITIALIZED BIT(2)

struct fwnode_handle {
struct fwnode_handle *secondary;
@@ -161,6 +164,18 @@ static inline void fwnode_init(struct fwnode_handle *fwnode,
INIT_LIST_HEAD(&fwnode->suppliers);
}

+static inline void fwnode_dev_initialized(struct fwnode_handle *fwnode,
+ bool initialized)
+{
+ if (IS_ERR_OR_NULL(fwnode))
+ return;
+
+ if (initialized)
+ fwnode->flags |= FWNODE_FLAG_INITIALIZED;
+ else
+ fwnode->flags &= ~FWNODE_FLAG_INITIALIZED;
+}
+
extern u32 fw_devlink_get_flags(void);
extern bool fw_devlink_is_strict(void);
int fwnode_link_add(struct fwnode_handle *con, struct fwnode_handle *sup);
--
2.30.0.478.g8a0d178c01-goog
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