Re: [PATCH V2 2/4] usb: gadget: configfs: Create control_config group

[Jerry Zhang]

Sorry I must have messed up in-reply-to. Patch 1 was sent here:
https://www.spinics.net/lists/linux-usb/msg167994.html. It didn't need a V2
and so I didn't resend it.

--Jerry
On Tue, May 15, 2018 at 11:15 PM Felipe Balbi  wrote:

> Jerry Zhang  writes:

> > Control_config is a group under gadget that acts
> > as a normal config group, except it does not
> > appear in cdev->configs.
> >
> > Functions that have exactly zero descriptors can
> > be linked into control_config. These functions
> > are bound and unbound with the rest of the gadget,
> > but are never enabled. Also, functions with zero
> > descriptors cannot be used in real configs.
> >
> > Create configfs_setup(), which will first attempt
> > composite setup. If that fails, it will go through
> > functions in control_config and use req_match to
> > find and deliver the request to a function that can
> > handle it.
> >
> > This allows the user to create a functionfs instance
> > dedicated to handling non-standard control requests
> > no matter what functions or configurations are
> > currently active.
> >
> > Signed-off-by: Jerry Zhang 

> I didn't get patch 1

> --
> balbi
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Re: [PATCH V2 2/4] usb: gadget: configfs: Create control_config group

[Felipe Balbi]

Jerry Zhang  writes:

> Control_config is a group under gadget that acts
> as a normal config group, except it does not
> appear in cdev->configs.
>
> Functions that have exactly zero descriptors can
> be linked into control_config. These functions
> are bound and unbound with the rest of the gadget,
> but are never enabled. Also, functions with zero
> descriptors cannot be used in real configs.
>
> Create configfs_setup(), which will first attempt
> composite setup. If that fails, it will go through
> functions in control_config and use req_match to
> find and deliver the request to a function that can
> handle it.
>
> This allows the user to create a functionfs instance
> dedicated to handling non-standard control requests
> no matter what functions or configurations are
> currently active.
>
> Signed-off-by: Jerry Zhang 

I didn't get patch 1

-- 
balbi


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[PATCH V2 2/4] usb: gadget: configfs: Create control_config group

[Jerry Zhang]

Control_config is a group under gadget that acts
as a normal config group, except it does not
appear in cdev->configs.

Functions that have exactly zero descriptors can
be linked into control_config. These functions
are bound and unbound with the rest of the gadget,
but are never enabled. Also, functions with zero
descriptors cannot be used in real configs.

Create configfs_setup(), which will first attempt
composite setup. If that fails, it will go through
functions in control_config and use req_match to
find and deliver the request to a function that can
handle it.

This allows the user to create a functionfs instance
dedicated to handling non-standard control requests
no matter what functions or configurations are
currently active.

Signed-off-by: Jerry Zhang 
---

Changes in V2:
- Added config_item_type for control_config without default attrs
- Changed bind to fail if the wrong kind of function is linked to
a normal config or control_config
- Changed bind to fail if a control function has no req_match, instead
of skipping it over

 drivers/usb/gadget/configfs.c | 114 --
 1 file changed, 96 insertions(+), 18 deletions(-)

diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c
index efba66ca0719..ed3d675ee7bb 100644
--- a/drivers/usb/gadget/configfs.c
+++ b/drivers/usb/gadget/configfs.c
@@ -44,12 +44,22 @@ int check_user_usb_string(const char *name,
 
 static const struct usb_descriptor_header *otg_desc[2];
 
+struct config_usb_cfg {
+   struct config_group group;
+   struct config_group strings_group;
+   struct list_head string_list;
+   struct usb_configuration c;
+   struct list_head func_list;
+   struct usb_gadget_strings *gstrings[MAX_USB_STRING_LANGS + 1];
+};
+
 struct gadget_info {
struct config_group group;
struct config_group functions_group;
struct config_group configs_group;
struct config_group strings_group;
struct config_group os_desc_group;
+   struct config_usb_cfg control_config;
 
struct mutex lock;
struct usb_gadget_strings *gstrings[MAX_USB_STRING_LANGS + 1];
@@ -68,15 +78,6 @@ static inline struct gadget_info *to_gadget_info(struct 
config_item *item)
 return container_of(to_config_group(item), struct gadget_info, group);
 }
 
-struct config_usb_cfg {
-   struct config_group group;
-   struct config_group strings_group;
-   struct list_head string_list;
-   struct usb_configuration c;
-   struct list_head func_list;
-   struct usb_gadget_strings *gstrings[MAX_USB_STRING_LANGS + 1];
-};
-
 static inline struct config_usb_cfg *to_config_usb_cfg(struct config_item 
*item)
 {
return container_of(to_config_group(item), struct config_usb_cfg,
@@ -512,6 +513,16 @@ static const struct config_item_type gadget_config_type = {
.ct_owner   = THIS_MODULE,
 };
 
+static struct configfs_item_operations control_config_item_ops = {
+   .allow_link = config_usb_cfg_link,
+   .drop_link  = config_usb_cfg_unlink,
+};
+
+static const struct config_item_type control_config_type = {
+   .ct_item_ops= _config_item_ops,
+   .ct_owner   = THIS_MODULE,
+};
+
 static const struct config_item_type gadget_root_type = {
.ct_item_ops= _root_item_ops,
.ct_attrs   = gadget_root_attrs,
@@ -1205,11 +1216,10 @@ int composite_os_desc_req_prepare(struct 
usb_composite_dev *cdev,
 static void purge_configs_funcs(struct gadget_info *gi)
 {
struct usb_configuration*c;
+   struct usb_function *f, *tmp;
+   struct config_usb_cfg *cfg;
 
list_for_each_entry(c, >cdev.configs, list) {
-   struct usb_function *f, *tmp;
-   struct config_usb_cfg *cfg;
-
cfg = container_of(c, struct config_usb_cfg, c);
 
list_for_each_entry_safe(f, tmp, >functions, list) {
@@ -1229,6 +1239,14 @@ static void purge_configs_funcs(struct gadget_info *gi)
c->highspeed = 0;
c->fullspeed = 0;
}
+
+   cfg = >control_config;
+   c = >c;
+   list_for_each_entry_safe(f, tmp, >functions, list) {
+   list_move_tail(>list, >func_list);
+   if (f->unbind)
+   f->unbind(c, f);
+   }
 }
 
 static int configfs_composite_bind(struct usb_gadget *gadget,
@@ -1242,6 +1260,9 @@ static int configfs_composite_bind(struct usb_gadget 
*gadget,
struct usb_string   *s;
unsignedi;
int ret;
+   struct config_usb_cfg *cfg;
+   struct usb_function *f;
+   struct usb_function *tmp;
 
/* the gi->lock is hold by the caller */
cdev->gadget = gadget;
@@ -1260,8 +1281,6 @@ static int configfs_composite_bind(struct usb_gadget 
*gadget,
 
 
list_for_each_entry(c, >cdev.configs, list) {
-