This patch provides an infrastructure to register & unregister a USB
function. This allows to turn a function into a module and avoid the
'#include "f_.*.c"' magic and we get a clear API / cut between the bare
gadget and its functions.
The concept is simple:
Each function defines the DECLARE_USB_FUNCTION_INIT macro whith an unique
name of the function and an allocation function. The name is used for
automaticaly loading the module if it is not yet present and request the
function from the gadget because we don't include the functions anymore.
The allocate function is mostly the "old" bind-callback which was passed
to usb_add_config() with a minor change:
- a function de-allocate function
This is mostly the same thing that is done by the unbind function. It
is called from within the function on "free" instead from the unbind
path on gadget removal.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
---
drivers/usb/gadget/Makefile | 2 +-
drivers/usb/gadget/composite.c | 53 +++++++++++++---------
drivers/usb/gadget/functions.c | 96 ++++++++++++++++++++++++++++++++++++++++
include/linux/usb/composite.h | 44 ++++++++++++++++++
4 files changed, 174 insertions(+), 21 deletions(-)
create mode 100644 drivers/usb/gadget/functions.c
diff --git a/drivers/usb/gadget/Makefile b/drivers/usb/gadget/Makefile
index 307be5f..fa65050 100644
--- a/drivers/usb/gadget/Makefile
+++ b/drivers/usb/gadget/Makefile
@@ -6,7 +6,7 @@ ccflags-$(CONFIG_USB_GADGET_DEBUG) := -DDEBUG
obj-$(CONFIG_USB_GADGET) += udc-core.o
obj-$(CONFIG_USB_LIBCOMPOSITE) += libcomposite.o
libcomposite-y := usbstring.o config.o epautoconf.o
-libcomposite-y += composite.o
+libcomposite-y += composite.o functions.o
obj-$(CONFIG_USB_DUMMY_HCD) += dummy_hcd.o
obj-$(CONFIG_USB_NET2272) += net2272.o
obj-$(CONFIG_USB_NET2280) += net2280.o
diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index 4eb07c7..c46ae24 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -664,6 +664,35 @@ static int set_config(struct usb_composite_dev *cdev,
return result;
}
+int usb_add_config_only(struct usb_composite_dev *cdev,
+ struct usb_configuration *config)
+{
+ struct usb_configuration *c;
+
+ DBG(cdev, "adding config #%u '%s'/%p\n",
+ config->bConfigurationValue,
+ config->label, config);
+
+ if (!config->bConfigurationValue)
+ return -EINVAL;
+
+ /* Prevent duplicate configuration identifiers */
+ list_for_each_entry(c, &cdev->configs, list) {
+ if (c->bConfigurationValue == config->bConfigurationValue)
+ return -EBUSY;
+ }
+
+ config->cdev = cdev;
+ list_add_tail(&config->list, &cdev->configs);
+
+ INIT_LIST_HEAD(&config->functions);
+ config->next_interface_id = 0;
+ memset(config->interface, 0, sizeof(config->interface));
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(usb_add_config_only);
+
/**
* usb_add_config() - add a configuration to a device.
* @cdev: wraps the USB gadget
@@ -684,29 +713,13 @@ int usb_add_config(struct usb_composite_dev *cdev,
int (*bind)(struct usb_configuration *))
{
int status = -EINVAL;
- struct usb_configuration *c;
-
- DBG(cdev, "adding config #%u '%s'/%p\n",
- config->bConfigurationValue,
- config->label, config);
- if (!config->bConfigurationValue || !bind)
+ if (!bind)
goto done;
- /* Prevent duplicate configuration identifiers */
- list_for_each_entry(c, &cdev->configs, list) {
- if (c->bConfigurationValue == config->bConfigurationValue) {
- status = -EBUSY;
- goto done;
- }
- }
-
- config->cdev = cdev;
- list_add_tail(&config->list, &cdev->configs);
-
- INIT_LIST_HEAD(&config->functions);
- config->next_interface_id = 0;
- memset(config->interface, 0, sizeof(config->interface));
+ status = usb_add_config_only(cdev, config);
+ if (status)
+ goto done;
status = bind(config);
if (status < 0) {
diff --git a/drivers/usb/gadget/functions.c b/drivers/usb/gadget/functions.c
new file mode 100644
index 0000000..5e5fee5
--- /dev/null
+++ b/drivers/usb/gadget/functions.c
@@ -0,0 +1,96 @@
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/err.h>
+
+#include <linux/usb/composite.h>
+
+static LIST_HEAD(func_list);
+static DEFINE_MUTEX(func_lock);
+
+static struct usb_function *try_get_usb_function(const char *name)
+{
+ struct usb_d_function *f;
+ struct usb_function *uf;
+
+ uf = ERR_PTR(-ENOENT);
+ mutex_lock(&func_lock);
+ list_for_each_entry(f, &func_list, list) {
+
+ if (strcmp(name, f->name))
+ continue;
+
+ if (!try_module_get(f->mod)) {
+ uf = ERR_PTR(-EBUSY);
+ break;
+ }
+ uf = f->alloc();
+ if (uf) {
+ uf->mod = f->mod;
+ } else {
+ module_put(f->mod);
+ uf = ERR_PTR(-ENOMEM);
+ }
+ break;
+ }
+ mutex_unlock(&func_lock);
+ return uf;
+}
+
+struct usb_function *usb_get_function(const char *name)
+{
+ struct usb_function *uf;
+ int ret;
+
+ uf = try_get_usb_function(name);
+ if (!IS_ERR(uf))
+ return uf;
+ ret = PTR_ERR(uf);
+ if (ret != -ENOENT)
+ return uf;
+ ret = request_module("usbfunc:%s", name);
+ if (ret < 0)
+ return ERR_PTR(ret);
+ return try_get_usb_function(name);
+}
+EXPORT_SYMBOL_GPL(usb_get_function);
+
+void usb_put_function(struct usb_function *f)
+{
+ struct module *mod;
+
+ if (!f)
+ return;
+ mod = f->mod;
+ f->free_func(f);
+ module_put(mod);
+}
+EXPORT_SYMBOL_GPL(usb_put_function);
+
+int usb_function_register(struct usb_d_function *newf)
+{
+ struct usb_d_function *f;
+ int ret;
+
+ ret = -EEXIST;
+
+ mutex_lock(&func_lock);
+ list_for_each_entry(f, &func_list, list) {
+ if (!strcmp(f->name, newf->name))
+ goto out;
+ }
+ ret = 0;
+ list_add_tail(&newf->list, &func_list);
+out:
+ mutex_unlock(&func_lock);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(usb_function_register);
+
+void usb_function_unregister(struct usb_d_function *f)
+{
+ mutex_lock(&func_lock);
+ list_del(&f->list);
+ mutex_unlock(&func_lock);
+}
+EXPORT_SYMBOL_GPL(usb_function_unregister);
diff --git a/include/linux/usb/composite.h b/include/linux/usb/composite.h
index b09c37e..0e2745e 100644
--- a/include/linux/usb/composite.h
+++ b/include/linux/usb/composite.h
@@ -116,6 +116,7 @@ struct usb_configuration;
* two or more distinct instances within the same configuration, providing
* several independent logical data links to a USB host.
*/
+
struct usb_function {
const char *name;
struct usb_gadget_strings **strings;
@@ -136,6 +137,9 @@ struct usb_function {
struct usb_function *);
void (*unbind)(struct usb_configuration *,
struct usb_function *);
+ /* */
+ void (*free_func)(struct usb_function *f);
+ struct module *mod;
/* runtime state management */
int (*set_alt)(struct usb_function *,
@@ -431,6 +435,46 @@ static inline u16 get_default_bcdDevice(void)
return bcdDevice;
}
+typedef struct usb_function *(*usb_func_alloc)(void);
+typedef void (*usb_func_free)(struct usb_function *f);
+
+struct usb_d_function {
+ const char *name;
+ struct module *mod;
+ struct list_head list;
+ usb_func_alloc alloc;
+};
+
+void usb_function_unregister(struct usb_d_function *f);
+int usb_function_register(struct usb_d_function *newf);
+void usb_put_function(struct usb_function *f);
+struct usb_function *usb_get_function(const char *name);
+struct usb_configuration *usb_get_config(struct usb_composite_dev *cdev,
+ int val);
+int usb_add_config_only(struct usb_composite_dev *cdev,
+ struct usb_configuration *config);
+
+#define DECLARE_USB_FUNCTION(_name, _alloc) \
+ static struct usb_d_function _name ## usb_func = { \
+ .name = __stringify(_name), \
+ .mod = THIS_MODULE, \
+ .alloc = _alloc, \
+ }; \
+ MODULE_ALIAS("usbfunc:"__stringify(_name));
+
+#define DECLARE_USB_FUNCTION_INIT(_name, _alloc) \
+ DECLARE_USB_FUNCTION(_name, _alloc) \
+ static int __init _name ## mod_init(void) \
+ { \
+ return usb_function_register(&_name ## usb_func); \
+ } \
+ static void __exit _name ## mod_exit(void) \
+ { \
+ usb_function_unregister(&_name ## usb_func); \
+ } \
+ module_init(_name ## mod_init); \
+ module_exit(_name ## mod_exit)
+
/* messaging utils */
#define DBG(d, fmt, args...) \
dev_dbg(&(d)->gadget->dev , fmt , ## args)
--
1.7.10.4
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
