[RFC PATCH 2/5] driver core: introduce global device ADD/DEL notifier

2012-12-02 Thread Ming Lei 
The global device ADD/DEL notifier is introduced so that
some platform code can bind some device resource to the
device. When this platform code runs, there is no any bus
information about the device, so have to resort to the
global notifier.

Cc: Andy Green andy.gr...@linaro.org
Cc: Roger Quadros rog...@ti.com
Cc: Alan Stern st...@rowland.harvard.edu
Cc: Felipe Balbi ba...@ti.com
Signed-off-by: Ming Lei tom.leim...@gmail.com
---
 drivers/base/core.c|   21 +
 include/linux/device.h |   13 +
 2 files changed, 34 insertions(+)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index a235085..37f11ff 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -43,6 +43,9 @@ static __init int sysfs_deprecated_setup(char *arg)
 early_param(sysfs.deprecated, sysfs_deprecated_setup);
 #endif
 
+/* global device nofifier */
+struct blocking_notifier_head dev_notifier;
+
 int (*platform_notify)(struct device *dev) = NULL;
 int (*platform_notify_remove)(struct device *dev) = NULL;
 static struct kobject *dev_kobj;
@@ -1041,6 +1044,8 @@ int device_add(struct device *dev)
if (platform_notify)
platform_notify(dev);
 
+   blocking_notifier_call_chain(dev_notifier, DEV_NOTIFY_ADD_DEVICE, dev);
+
error = device_create_file(dev, uevent_attr);
if (error)
goto attrError;
@@ -1228,6 +1233,7 @@ void device_del(struct device *dev)
device_pm_remove(dev);
driver_deferred_probe_del(dev);
 
+   blocking_notifier_call_chain(dev_notifier, DEV_NOTIFY_DEL_DEVICE, dev);
/* Notify the platform of the removal, in case they
 * need to do anything...
 */
@@ -1376,6 +1382,8 @@ struct device *device_find_child(struct device *parent, 
void *data,
 
 int __init devices_init(void)
 {
+   BLOCKING_INIT_NOTIFIER_HEAD(dev_notifier);
+
devices_kset = kset_create_and_add(devices, device_uevent_ops, NULL);
if (!devices_kset)
return -ENOMEM;
@@ -1995,6 +2003,19 @@ int dev_printk(const char *level, const struct device 
*dev,
 }
 EXPORT_SYMBOL(dev_printk);
 
+/* The notifier should be avoided as far as possible */
+int dev_register_notifier(struct notifier_block *nb)
+{
+   return blocking_notifier_chain_register(dev_notifier, nb);
+}
+EXPORT_SYMBOL_GPL(dev_register_notifier);
+
+int dev_unregister_notifier(struct notifier_block *nb)
+{
+   return blocking_notifier_chain_unregister(dev_notifier, nb);
+}
+EXPORT_SYMBOL_GPL(dev_unregister_notifier);
+
 #define define_dev_printk_level(func, kern_level)  \
 int func(const struct device *dev, const char *fmt, ...)   \
 {  \
diff --git a/include/linux/device.h b/include/linux/device.h
index 43dcda9..aeb54f6 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -179,6 +179,19 @@ extern int bus_unregister_notifier(struct bus_type *bus,
 #define BUS_NOTIFY_UNBOUND_DRIVER  0x0006 /* driver is unbound
  from the device */
 
+/* All 2 notifers below get called with the target struct device *
+ * as an argument. Note that those functions are likely to be called
+ * with the device lock held in the core, so be careful.
+ */
+#define DEV_NOTIFY_ADD_DEVICE  0x0001 /* device added */
+#define DEV_NOTIFY_DEL_DEVICE  0x0002 /* device removed */
+extern int dev_register_notifier(struct notifier_block *nb);
+extern int dev_unregister_notifier(struct notifier_block *nb);
+
+extern struct kset *bus_get_kset(struct bus_type *bus);
+extern struct klist *bus_get_device_klist(struct bus_type *bus);
+
+
 extern struct kset *bus_get_kset(struct bus_type *bus);
 extern struct klist *bus_get_device_klist(struct bus_type *bus);
 
-- 
1.7.9.5

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Re: [RFC PATCH 2/5] driver core: introduce global device ADD/DEL notifier

2012-12-02 Thread Andy Green 

On 02/12/12 23:01, the mail apparently from Ming Lei included:

The global device ADD/DEL notifier is introduced so that
some platform code can bind some device resource to the
device. When this platform code runs, there is no any bus
information about the device, so have to resort to the
global notifier.

Cc: Andy Green andy.gr...@linaro.org
Cc: Roger Quadros rog...@ti.com
Cc: Alan Stern st...@rowland.harvard.edu
Cc: Felipe Balbi ba...@ti.com
Signed-off-by: Ming Lei tom.leim...@gmail.com
---
  drivers/base/core.c|   21 +
  include/linux/device.h |   13 +
  2 files changed, 34 insertions(+)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index a235085..37f11ff 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -43,6 +43,9 @@ static __init int sysfs_deprecated_setup(char *arg)
  early_param(sysfs.deprecated, sysfs_deprecated_setup);
  #endif

+/* global device nofifier */
+struct blocking_notifier_head dev_notifier;
+
  int (*platform_notify)(struct device *dev) = NULL;
  int (*platform_notify_remove)(struct device *dev) = NULL;
  static struct kobject *dev_kobj;
@@ -1041,6 +1044,8 @@ int device_add(struct device *dev)
if (platform_notify)
platform_notify(dev);

+   blocking_notifier_call_chain(dev_notifier, DEV_NOTIFY_ADD_DEVICE, dev);
+
error = device_create_file(dev, uevent_attr);
if (error)
goto attrError;
@@ -1228,6 +1233,7 @@ void device_del(struct device *dev)
device_pm_remove(dev);
driver_deferred_probe_del(dev);

+   blocking_notifier_call_chain(dev_notifier, DEV_NOTIFY_DEL_DEVICE, dev);
/* Notify the platform of the removal, in case they
 * need to do anything...
 */
@@ -1376,6 +1382,8 @@ struct device *device_find_child(struct device *parent, 
void *data,

  int __init devices_init(void)
  {
+   BLOCKING_INIT_NOTIFIER_HEAD(dev_notifier);
+
devices_kset = kset_create_and_add(devices, device_uevent_ops, NULL);
if (!devices_kset)
return -ENOMEM;
@@ -1995,6 +2003,19 @@ int dev_printk(const char *level, const struct device 
*dev,
  }
  EXPORT_SYMBOL(dev_printk);

+/* The notifier should be avoided as far as possible */
+int dev_register_notifier(struct notifier_block *nb)
+{
+   return blocking_notifier_chain_register(dev_notifier, nb);
+}
+EXPORT_SYMBOL_GPL(dev_register_notifier);
+
+int dev_unregister_notifier(struct notifier_block *nb)
+{
+   return blocking_notifier_chain_unregister(dev_notifier, nb);
+}
+EXPORT_SYMBOL_GPL(dev_unregister_notifier);
+
  #define define_dev_printk_level(func, kern_level) \
  int func(const struct device *dev, const char *fmt, ...)  \
  { \
diff --git a/include/linux/device.h b/include/linux/device.h
index 43dcda9..aeb54f6 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -179,6 +179,19 @@ extern int bus_unregister_notifier(struct bus_type *bus,
  #define BUS_NOTIFY_UNBOUND_DRIVER 0x0006 /* driver is unbound
  from the device */

+/* All 2 notifers below get called with the target struct device *
+ * as an argument. Note that those functions are likely to be called
+ * with the device lock held in the core, so be careful.
+ */
+#define DEV_NOTIFY_ADD_DEVICE  0x0001 /* device added */
+#define DEV_NOTIFY_DEL_DEVICE  0x0002 /* device removed */
+extern int dev_register_notifier(struct notifier_block *nb);
+extern int dev_unregister_notifier(struct notifier_block *nb);
+
+extern struct kset *bus_get_kset(struct bus_type *bus);
+extern struct klist *bus_get_device_klist(struct bus_type *bus);
+
+
  extern struct kset *bus_get_kset(struct bus_type *bus);
  extern struct klist *bus_get_device_klist(struct bus_type *bus);


Device de/registraton time is not necessarily a good choice for the 
notification point.  At boot time, platform_devices may be being 
registered with no sign of driver and anything getting enabled in the 
notifier without further filtering (at each notifier...) will then 
always be enabled the whole session whether in use or not.


probe() and remove() are more interesting because at that point the 
driver is present and we're definitely instantiating the thing or 
finished with its instantiation, and it's valid for non-usb devices too.


In the one case you're servicing in the series, usb hub port, the device 
is very unusual in that it has no driver.  However if you're going to 
add a global notifier in generic device code, you should have it do the 
right thing for normal device case so other people can use it... how I 
solved this for hub port was to simply normalize hub port by introducing 
a stub driver for it, so you get a probe / remove like anything else.


-Andy

--
Andy Green | TI Landing Team Leader
Linaro.org │ Open source software for ARM SoCs | Follow Linaro

Re: [RFC PATCH 2/5] driver core: introduce global device ADD/DEL notifier

2012-12-02 Thread Ming Lei 
On Mon, Dec 3, 2012 at 12:13 AM, Andy Green andy.gr...@linaro.org wrote:
 On 02/12/12 23:01, the mail apparently from Ming Lei included:

 The global device ADD/DEL notifier is introduced so that
 some platform code can bind some device resource to the
 device. When this platform code runs, there is no any bus
 information about the device, so have to resort to the
 global notifier.

 Cc: Andy Green andy.gr...@linaro.org
 Cc: Roger Quadros rog...@ti.com
 Cc: Alan Stern st...@rowland.harvard.edu
 Cc: Felipe Balbi ba...@ti.com
 Signed-off-by: Ming Lei tom.leim...@gmail.com
 ---
   drivers/base/core.c|   21 +
   include/linux/device.h |   13 +
   2 files changed, 34 insertions(+)

 diff --git a/drivers/base/core.c b/drivers/base/core.c
 index a235085..37f11ff 100644
 --- a/drivers/base/core.c
 +++ b/drivers/base/core.c
 @@ -43,6 +43,9 @@ static __init int sysfs_deprecated_setup(char *arg)
   early_param(sysfs.deprecated, sysfs_deprecated_setup);
   #endif

 +/* global device nofifier */
 +struct blocking_notifier_head dev_notifier;
 +
   int (*platform_notify)(struct device *dev) = NULL;
   int (*platform_notify_remove)(struct device *dev) = NULL;
   static struct kobject *dev_kobj;
 @@ -1041,6 +1044,8 @@ int device_add(struct device *dev)
 if (platform_notify)
 platform_notify(dev);

 +   blocking_notifier_call_chain(dev_notifier, DEV_NOTIFY_ADD_DEVICE,
 dev);
 +
 error = device_create_file(dev, uevent_attr);
 if (error)
 goto attrError;
 @@ -1228,6 +1233,7 @@ void device_del(struct device *dev)
 device_pm_remove(dev);
 driver_deferred_probe_del(dev);

 +   blocking_notifier_call_chain(dev_notifier, DEV_NOTIFY_DEL_DEVICE,
 dev);
 /* Notify the platform of the removal, in case they
  * need to do anything...
  */
 @@ -1376,6 +1382,8 @@ struct device *device_find_child(struct device
 *parent, void *data,

   int __init devices_init(void)
   {
 +   BLOCKING_INIT_NOTIFIER_HEAD(dev_notifier);
 +
 devices_kset = kset_create_and_add(devices, device_uevent_ops,
 NULL);
 if (!devices_kset)
 return -ENOMEM;
 @@ -1995,6 +2003,19 @@ int dev_printk(const char *level, const struct
 device *dev,
   }
   EXPORT_SYMBOL(dev_printk);

 +/* The notifier should be avoided as far as possible */
 +int dev_register_notifier(struct notifier_block *nb)
 +{
 +   return blocking_notifier_chain_register(dev_notifier, nb);
 +}
 +EXPORT_SYMBOL_GPL(dev_register_notifier);
 +
 +int dev_unregister_notifier(struct notifier_block *nb)
 +{
 +   return blocking_notifier_chain_unregister(dev_notifier, nb);
 +}
 +EXPORT_SYMBOL_GPL(dev_unregister_notifier);
 +
   #define define_dev_printk_level(func, kern_level) \
   int func(const struct device *dev, const char *fmt, ...)  \
   { \
 diff --git a/include/linux/device.h b/include/linux/device.h
 index 43dcda9..aeb54f6 100644
 --- a/include/linux/device.h
 +++ b/include/linux/device.h
 @@ -179,6 +179,19 @@ extern int bus_unregister_notifier(struct bus_type
 *bus,
   #define BUS_NOTIFY_UNBOUND_DRIVER 0x0006 /* driver is unbound
   from the device */

 +/* All 2 notifers below get called with the target struct device *
 + * as an argument. Note that those functions are likely to be called
 + * with the device lock held in the core, so be careful.
 + */
 +#define DEV_NOTIFY_ADD_DEVICE  0x0001 /* device added */
 +#define DEV_NOTIFY_DEL_DEVICE  0x0002 /* device removed */
 +extern int dev_register_notifier(struct notifier_block *nb);
 +extern int dev_unregister_notifier(struct notifier_block *nb);
 +
 +extern struct kset *bus_get_kset(struct bus_type *bus);
 +extern struct klist *bus_get_device_klist(struct bus_type *bus);
 +
 +
   extern struct kset *bus_get_kset(struct bus_type *bus);
   extern struct klist *bus_get_device_klist(struct bus_type *bus);


 Device de/registraton time is not necessarily a good choice for the
 notification point.  At boot time, platform_devices may be being registered
 with no sign of driver and anything getting enabled in the notifier without
 further filtering (at each notifier...) will then always be enabled the
 whole session whether in use or not.

 probe() and remove() are more interesting because at that point the driver
 is present and we're definitely instantiating the thing or finished with its
 instantiation, and it's valid for non-usb devices too.

 In the one case you're servicing in the series, usb hub port, the device is
 very unusual in that it has no driver.  However if you're going to add a
 global notifier in generic device code, you should have it do the right
 thing for normal device case so other people can use it... how I solved this
 for hub port was to simply normalize hub port by introducing a stub driver
 for