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 two allocation functions.
- one to create an "instance". The instance holds the current configuration
set. In case there are two usb_configudations with one function there will
be one instance and two usb_functions
- one to create an "function" from the instance.
The name of the instance is used to automaticaly load the module if it the
instance is not yet available.
The usb_function callbacks are slightly modified and extended:
- usb_get_function()
creates a struct usb_function inclunding all pointers (bind,
unbind,…). It uses the "instance" to map its configuration. So we can
have _two_ struct usb_function, one for each usb_configuration.
- ->unbind()
Since the struct usb_function was not allocated in ->bind() it should
not kfree()d here. This function should only reverse what happens in
->bind() that is request cleanup and the cleanup of allocated
descriptors.
- ->free_func()
a simple kfree() of the struct usb_function
Signed-off-by: Sebastian Andrzej Siewior <bige...@linutronix.de>
---
drivers/usb/gadget/Makefile | 2 +-
drivers/usb/gadget/composite.c | 47 ++++++++++-------
drivers/usb/gadget/functions.c | 110 ++++++++++++++++++++++++++++++++++++++++
include/linux/usb/composite.h | 52 +++++++++++++++++++
4 files changed, 193 insertions(+), 18 deletions(-)
create mode 100644 drivers/usb/gadget/functions.c
diff --git a/drivers/usb/gadget/Makefile b/drivers/usb/gadget/Makefile
index 8b4acfd..fef41f5 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..3c460ff 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -664,6 +664,31 @@ 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;
+
+ 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
@@ -684,30 +709,18 @@ int usb_add_config(struct usb_composite_dev *cdev,
int (*bind)(struct usb_configuration *))
{
int status = -EINVAL;
- struct usb_configuration *c;
+
+ if (!bind)
+ goto done;
DBG(cdev, "adding config #%u '%s'/%p\n",
config->bConfigurationValue,
config->label, config);
- if (!config->bConfigurationValue || !bind)
+ status = usb_add_config_only(cdev, config);
+ if (status)
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 = bind(config);
if (status < 0) {
while (!list_empty(&config->functions)) {
diff --git a/drivers/usb/gadget/functions.c b/drivers/usb/gadget/functions.c
new file mode 100644
index 0000000..f9cdf8e
--- /dev/null
+++ b/drivers/usb/gadget/functions.c
@@ -0,0 +1,110 @@
+#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_instance *try_get_usb_function_instance(const char
*name)
+{
+ struct usb_function_driver *fd;
+ struct usb_function_instance *fi;
+
+ fi = ERR_PTR(-ENOENT);
+ mutex_lock(&func_lock);
+ list_for_each_entry(fd, &func_list, list) {
+
+ if (strcmp(name, fd->name))
+ continue;
+
+ if (!try_module_get(fd->mod)) {
+ fi = ERR_PTR(-EBUSY);
+ break;
+ }
+ fi = fd->alloc_inst();
+ if (IS_ERR(fi))
+ module_put(fd->mod);
+ else
+ fi->fd = fd;
+ break;
+ }
+ mutex_unlock(&func_lock);
+ return fi;
+}
+
+struct usb_function_instance *usb_get_function_instance(const char *name)
+{
+ struct usb_function_instance *fi;
+ int ret;
+
+ fi = try_get_usb_function_instance(name);
+ if (!IS_ERR(fi))
+ return fi;
+ ret = PTR_ERR(fi);
+ if (ret != -ENOENT)
+ return fi;
+ ret = request_module("usbfunc:%s", name);
+ if (ret < 0)
+ return ERR_PTR(ret);
+ return try_get_usb_function_instance(name);
+}
+EXPORT_SYMBOL_GPL(usb_get_function_instance);
+
+struct usb_function *usb_get_function(struct usb_function_instance *fi)
+{
+ return fi->fd->alloc_func(fi);
+}
+EXPORT_SYMBOL_GPL(usb_get_function);
+
+void usb_put_function_instance(struct usb_function_instance *fi)
+{
+ struct module *mod;
+
+ if (!fi)
+ return;
+
+ mod = fi->fd->mod;
+ fi->free_func_inst(fi);
+ module_put(mod);
+}
+EXPORT_SYMBOL_GPL(usb_put_function_instance);
+
+void usb_put_function(struct usb_function *f)
+{
+ if (!f)
+ return;
+
+ f->free_func(f);
+}
+EXPORT_SYMBOL_GPL(usb_put_function);
+
+int usb_function_register(struct usb_function_driver *newf)
+{
+ struct usb_function_driver *fd;
+ int ret;
+
+ ret = -EEXIST;
+
+ mutex_lock(&func_lock);
+ list_for_each_entry(fd, &func_list, list) {
+ if (!strcmp(fd->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_function_driver *fd)
+{
+ mutex_lock(&func_lock);
+ list_del(&fd->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..d0886c8 100644
--- a/include/linux/usb/composite.h
+++ b/include/linux/usb/composite.h
@@ -77,6 +77,8 @@ struct usb_configuration;
* in interface or class descriptors; endpoints; I/O buffers; and so on.
* @unbind: Reverses @bind; called as a side effect of unregistering the
* driver which added this function.
+ * @free_func: free the struct usb_function.
+ * @mod: (internal) points to the module that created this structure.
* @set_alt: (REQUIRED) Reconfigures altsettings; function drivers may
* initialize usb_ep.driver data at this time (when it is used).
* Note that setting an interface to its current altsetting resets
@@ -116,6 +118,7 @@ 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 +139,8 @@ 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 +436,53 @@ static inline u16 get_default_bcdDevice(void)
return bcdDevice;
}
+struct usb_function_driver {
+ const char *name;
+ struct module *mod;
+ struct list_head list;
+ struct usb_function_instance *(*alloc_inst)(void);
+ struct usb_function *(*alloc_func)(struct usb_function_instance *inst);
+};
+
+struct usb_function_instance {
+ struct usb_function_driver *fd;
+ void (*free_func_inst)(struct usb_function_instance *inst);
+};
+
+void usb_function_unregister(struct usb_function_driver *f);
+int usb_function_register(struct usb_function_driver *newf);
+void usb_put_function_instance(struct usb_function_instance *fi);
+void usb_put_function(struct usb_function *f);
+struct usb_function_instance *usb_get_function_instance(const char *name);
+struct usb_function *usb_get_function(struct usb_function_instance *fi);
+
+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, _inst_alloc, _func_alloc) \
+ static struct usb_function_driver _name ## usb_func = { \
+ .name = __stringify(_name), \
+ .mod = THIS_MODULE, \
+ .alloc_inst = _inst_alloc, \
+ .alloc_func = _func_alloc, \
+ }; \
+ MODULE_ALIAS("usbfunc:"__stringify(_name));
+
+#define DECLARE_USB_FUNCTION_INIT(_name, _inst_alloc, _func_alloc) \
+ DECLARE_USB_FUNCTION(_name, _inst_alloc, _func_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
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