[char-misc-next 13/17] mei: bus: enable running fixup routines before device registration

[Tomas Winkler]

We split the device registration to allocation and device struct
initialization , setup, and final registration.
This way we can run fixups and quirks during the setup stage on
an initialized device. If a fixup sets do_match flag to false
the device won't be registered on the bus.

Signed-off-by: Tomas Winkler <tomas.winkler@xxxxxxxxx>
---
 drivers/misc/mei/bus-fixup.c | 30 +++++++++++++++
 drivers/misc/mei/bus.c       | 91 ++++++++++++++++++++++++++++++++++++--------
 drivers/misc/mei/mei_dev.h   |  2 +-
 include/linux/mei_cl_bus.h   |  4 ++
 4 files changed, 111 insertions(+), 16 deletions(-)

diff --git a/drivers/misc/mei/bus-fixup.c b/drivers/misc/mei/bus-fixup.c
index 9bd76cda1608..2c02a338f63b 100644
--- a/drivers/misc/mei/bus-fixup.c
+++ b/drivers/misc/mei/bus-fixup.c
@@ -20,12 +20,15 @@
 #include <linux/moduleparam.h>
 #include <linux/device.h>
 #include <linux/slab.h>
+#include <linux/uuid.h>
 
 #include <linux/mei_cl_bus.h>
 
 #include "mei_dev.h"
 #include "client.h"
 
+#define MEI_UUID_ANY NULL_UUID_LE
+
 struct mei_nfc_cmd {
 	u8 command;
 	u8 status;
@@ -411,4 +414,31 @@ void mei_nfc_host_exit(struct mei_device *bus)
 	mutex_unlock(&bus->device_lock);
 }
 
+#define MEI_FIXUP(_uuid, _hook) { _uuid, _hook }
+
+static struct mei_fixup {
+
+	const uuid_le uuid;
+	void (*hook)(struct mei_cl_device *cldev);
+} mei_fixups[] = {};
+
+/**
+ * mei_cl_dev_fixup - run fixup handlers
+ *
+ * @cldev: me client device
+ */
+void mei_cl_dev_fixup(struct mei_cl_device *cldev)
+{
+	struct mei_fixup *f;
+	const uuid_le *uuid = mei_me_cl_uuid(cldev->me_cl);
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(mei_fixups); i++) {
+
+		f = &mei_fixups[i];
+		if (uuid_le_cmp(f->uuid, MEI_UUID_ANY) == 0 ||
+		    uuid_le_cmp(f->uuid, *uuid) == 0)
+			f->hook(cldev);
+	}
+}
 
diff --git a/drivers/misc/mei/bus.c b/drivers/misc/mei/bus.c
index 592f2a1651bf..8ff824950597 100644
--- a/drivers/misc/mei/bus.c
+++ b/drivers/misc/mei/bus.c
@@ -435,6 +435,9 @@ static int mei_cl_device_match(struct device *dev, struct device_driver *drv)
 	if (!cldev)
 		return 0;
 
+	if (!cldev->do_match)
+		return 0;
+
 	if (!cldrv || !cldrv->id_table)
 		return 0;
 
@@ -660,6 +663,76 @@ struct mei_cl *mei_cl_bus_find_cl_by_uuid(struct mei_device *bus,
 	return NULL;
 }
 
+/**
+ * mei_cl_dev_alloc - initialize and allocate mei client device
+ *
+ * @bus: mei device
+ * @me_cl: me client
+ *
+ * Return: allocated device structur or NULL on allocation failure
+ */
+static struct mei_cl_device *mei_cl_dev_alloc(struct mei_device *bus,
+					      struct mei_me_client *me_cl)
+{
+	struct mei_cl_device *cldev;
+
+	cldev = kzalloc(sizeof(struct mei_cl_device), GFP_KERNEL);
+	if (!cldev)
+		return NULL;
+
+	device_initialize(&cldev->dev);
+	cldev->dev.parent = bus->dev;
+	cldev->dev.bus    = &mei_cl_bus_type;
+	cldev->dev.type   = &mei_cl_device_type;
+	cldev->bus        = mei_dev_bus_get(bus);
+	cldev->me_cl      = mei_me_cl_get(me_cl);
+	cldev->is_added   = 0;
+	INIT_LIST_HEAD(&cldev->bus_list);
+
+	return cldev;
+}
+
+/**
+ * mei_cl_dev_setup - setup me client device
+ *    run fix up routines and set the device name
+ *
+ * @bus: mei device
+ * @cldev: me client device
+ *
+ * Return: true if the device is eligible for enumeration
+ */
+static bool mei_cl_dev_setup(struct mei_device *bus,
+			     struct mei_cl_device *cldev)
+{
+	cldev->do_match = 1;
+	mei_cl_dev_fixup(cldev);
+
+	if (cldev->do_match)
+		dev_set_name(&cldev->dev, "mei:%s:%pUl",
+			     cldev->name, mei_me_cl_uuid(cldev->me_cl));
+
+	return cldev->do_match == 1;
+}
+
+/**
+ * mei_cl_bus_dev_add - add me client devices
+ *
+ * @cldev: me client device
+ *
+ * Return: 0 on success; < 0 on failre
+ */
+static int mei_cl_bus_dev_add(struct mei_cl_device *cldev)
+{
+	int ret;
+
+	dev_dbg(cldev->bus->dev, "adding %pUL\n", mei_me_cl_uuid(cldev->me_cl));
+	ret = device_add(&cldev->dev);
+	if (!ret)
+		cldev->is_added = 1;
+
+	return ret;
+}
+
 struct mei_cl_device *mei_cl_add_device(struct mei_device *bus,
 					struct mei_me_client *me_cl,
 					struct mei_cl *cl,
@@ -668,28 +741,16 @@ struct mei_cl_device *mei_cl_add_device(struct mei_device *bus,
 	struct mei_cl_device *cldev;
 	int status;
 
-	cldev = kzalloc(sizeof(struct mei_cl_device), GFP_KERNEL);
+	cldev = mei_cl_dev_alloc(bus, me_cl);
 	if (!cldev)
 		return NULL;
 
-	cldev->me_cl = mei_me_cl_get(me_cl);
-	if (!cldev->me_cl) {
-		kfree(cldev);
-		return NULL;
-	}
-
 	cldev->cl = cl;
-	cldev->dev.parent = bus->dev;
-	cldev->dev.bus = &mei_cl_bus_type;
-	cldev->dev.type = &mei_cl_device_type;
-	cldev->bus      = mei_dev_bus_get(bus);
-	INIT_LIST_HEAD(&cldev->bus_list);
-
 	strlcpy(cldev->name, name, sizeof(cldev->name));
 
-	dev_set_name(&cldev->dev, "mei:%s:%pUl", name, mei_me_cl_uuid(me_cl));
+	mei_cl_dev_setup(bus, cldev);
 
-	status = device_register(&cldev->dev);
+	status = mei_cl_bus_dev_add(cldev);
 	if (status) {
 		dev_err(bus->dev, "Failed to register MEI device\n");
 		mei_me_cl_put(cldev->me_cl);
diff --git a/drivers/misc/mei/mei_dev.h b/drivers/misc/mei/mei_dev.h
index 4ce11c98b61a..24c70fada758 100644
--- a/drivers/misc/mei/mei_dev.h
+++ b/drivers/misc/mei/mei_dev.h
@@ -335,7 +335,7 @@ struct mei_cl_device *mei_cl_add_device(struct mei_device *bus,
 					struct mei_cl *cl,
 					char *name);
 void mei_cl_remove_device(struct mei_cl_device *cldev);
-
+void mei_cl_dev_fixup(struct mei_cl_device *dev);
 ssize_t __mei_cl_send(struct mei_cl *cl, u8 *buf, size_t length,
 			bool blocking);
 ssize_t __mei_cl_recv(struct mei_cl *cl, u8 *buf, size_t length);
diff --git a/include/linux/mei_cl_bus.h b/include/linux/mei_cl_bus.h
index 85239138251c..81ab56dd0ae0 100644
--- a/include/linux/mei_cl_bus.h
+++ b/include/linux/mei_cl_bus.h
@@ -29,6 +29,8 @@ typedef void (*mei_cl_event_cb_t)(struct mei_cl_device *device,
  *	events (e.g. Rx buffer pending) notifications.
  * @event_context: event callback run context
  * @events: Events bitmask sent to the driver.
+ *
+ * @do_match: wheather device can be matched with a driver
  * @is_added: device is already scanned
  * @priv_data: client private data
  */
@@ -45,6 +47,8 @@ struct mei_cl_device {
 	mei_cl_event_cb_t event_cb;
 	void *event_context;
 	unsigned long events;
+
+	unsigned int do_match:1;
 	unsigned int is_added:1;
 
 	void *priv_data;
-- 
2.4.2

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