USB: gadget: added a saner gadget downloader registration API

Preprocessor definitions and hardcoded implementation selection in
g_dnl core were replaced by a linker list made of (usb_function_name,
bind_callback) pairs.

Signed-off-by: Mateusz Zalega <m.zalega@samsung.com>
Acked-by: Lukasz Majewski <l.majewski@samsung.com>
Acked-by: Marek Vasut <marex@denx.de>

common/cmd_dfu.c

@@ -22,7 +22,6 @@ static int do_dfu(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 	char *interface = argv[2];
 	char *devstring = argv[3];
 
-	char *s = "dfu";
 	int ret, i = 0;
 
 	ret = dfu_init_env_entities(interface, simple_strtoul(devstring,
@@ -38,7 +37,7 @@ static int do_dfu(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 	int controller_index = simple_strtoul(usb_controller, NULL, 0);
 	board_usb_init(controller_index, USB_INIT_DEVICE);
 
-	g_dnl_register(s);
+	g_dnl_register("usb_dnl_dfu");
 	while (1) {
 		if (dfu_reset())
 			/*

common/cmd_thordown.c

@@ -22,7 +22,6 @@ int do_thor_down(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 	char *interface = argv[2];
 	char *devstring = argv[3];
 
-	const char *s = "thor";
 	int ret;
 
 	puts("TIZEN \"THOR\" Downloader\n");
@@ -40,7 +39,7 @@ int do_thor_down(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 		goto exit;
 	}
 
-	g_dnl_register(s);
+	g_dnl_register("usb_dnl_thor");
 
 	ret = thor_init();
 	if (ret) {

common/cmd_usb_mass_storage.c

@@ -40,7 +40,7 @@ int do_usb_mass_storage(cmd_tbl_t *cmdtp, int flag,
 		return CMD_RET_FAILURE;
 	}
 
-	g_dnl_register("ums");
+	g_dnl_register("usb_dnl_ums");
 
 	/* Timeout unit: seconds */
 	int cable_ready_timeout = UMS_CABLE_READY_TIMEOUT;

drivers/usb/gadget/f_dfu.c

@@ -24,6 +24,7 @@
 #include <linux/usb/composite.h>
 
 #include <dfu.h>
+#include <g_dnl.h>
 #include "f_dfu.h"
 
 struct f_dfu {
@@ -817,3 +818,5 @@ int dfu_add(struct usb_configuration *c)
 
 	return dfu_bind_config(c);
 }
+
+DECLARE_GADGET_BIND_CALLBACK(usb_dnl_dfu, dfu_add);

drivers/usb/gadget/f_mass_storage.c

@@ -255,6 +255,7 @@
 #include <linux/usb/gadget.h>
 #include <linux/usb/composite.h>
 #include <usb/lin_gadget_compat.h>
+#include <g_dnl.h>
 
 /*------------------------------------------------------------------------*/
 
@@ -2778,3 +2779,5 @@ int fsg_init(struct ums *ums_dev)
 
 	return 0;
 }
+
+DECLARE_GADGET_BIND_CALLBACK(usb_dnl_ums, fsg_add);

drivers/usb/gadget/f_thor.c

@@ -1004,3 +1004,5 @@ int thor_add(struct usb_configuration *c)
 	debug("%s:\n", __func__);
 	return thor_func_init(c);
 }
+
+DECLARE_GADGET_BIND_CALLBACK(usb_dnl_thor, thor_add);

drivers/usb/gadget/g_dnl.c

@@ -41,7 +41,6 @@
 
 #define DRIVER_VERSION		"usb_dnl 2.0"
 
-static const char shortname[] = "usb_dnl_";
 static const char product[] = "USB download gadget";
 static char g_dnl_serial[MAX_STRING_SERIAL];
 static const char manufacturer[] = CONFIG_G_DNL_MANUFACTURER;
@@ -96,29 +95,36 @@ static int g_dnl_unbind(struct usb_composite_dev *cdev)
 	free(cdev->config);
 	cdev->config = NULL;
 	debug("%s: calling usb_gadget_disconnect for "
-			"controller '%s'\n", shortname, gadget->name);
+			"controller '%s'\n", __func__, gadget->name);
 	usb_gadget_disconnect(gadget);
 
 	return 0;
 }
 
+static inline struct g_dnl_bind_callback *g_dnl_bind_callback_first(void)
+{
+	return ll_entry_start(struct g_dnl_bind_callback,
+				g_dnl_bind_callbacks);
+}
+
+static inline struct g_dnl_bind_callback *g_dnl_bind_callback_end(void)
+{
+	return ll_entry_end(struct g_dnl_bind_callback,
+				g_dnl_bind_callbacks);
+}
+
 static int g_dnl_do_config(struct usb_configuration *c)
 {
 	const char *s = c->cdev->driver->name;
-	int ret = -1;
+	struct g_dnl_bind_callback *callback = g_dnl_bind_callback_first();
 
 	debug("%s: configuration: 0x%p composite dev: 0x%p\n",
 	      __func__, c, c->cdev);
 
-	printf("GADGET DRIVER: %s\n", s);
-	if (!strcmp(s, "usb_dnl_dfu"))
-		ret = dfu_add(c);
-	else if (!strcmp(s, "usb_dnl_ums"))
-		ret = fsg_add(c);
-	else if (!strcmp(s, "usb_dnl_thor"))
-		ret = thor_add(c);
-
-	return ret;
+	for (; callback != g_dnl_bind_callback_end(); callback++)
+		if (!strcmp(s, callback->usb_function_name))
+			return callback->fptr(c);
+	return -ENODEV;
 }
 
 static int g_dnl_config_register(struct usb_composite_dev *cdev)
@@ -208,12 +214,12 @@ static int g_dnl_bind(struct usb_composite_dev *cdev)
 		device_desc.bcdDevice = cpu_to_le16(gcnum);
 	else {
 		debug("%s: controller '%s' not recognized\n",
-			shortname, gadget->name);
+			__func__, gadget->name);
 		device_desc.bcdDevice = __constant_cpu_to_le16(0x9999);
 	}
 
 	debug("%s: calling usb_gadget_connect for "
-			"controller '%s'\n", shortname, gadget->name);
+			"controller '%s'\n", __func__, gadget->name);
 	usb_gadget_connect(gadget);
 
 	return 0;
@@ -232,36 +238,22 @@ static struct usb_composite_driver g_dnl_driver = {
 	.unbind = g_dnl_unbind,
 };
 
-int g_dnl_register(const char *type)
+/*
+ * NOTICE:
+ * Registering via USB function name won't be necessary after rewriting
+ * g_dnl to support multiple USB functions.
+ */
+int g_dnl_register(const char *name)
 {
-	/* The largest function name is 4 */
-	static char name[sizeof(shortname) + 4];
-	int ret;
-
-	if (!strcmp(type, "dfu")) {
-		strcpy(name, shortname);
-		strcat(name, type);
-	} else if (!strcmp(type, "ums")) {
-		strcpy(name, shortname);
-		strcat(name, type);
-	} else if (!strcmp(type, "thor")) {
-		strcpy(name, shortname);
-		strcat(name, type);
-	} else {
-		printf("%s: unknown command: %s\n", __func__, type);
-		return -EINVAL;
-	}
+	int ret = usb_composite_register(&g_dnl_driver);
 
+	debug("%s: g_dnl_driver.name = %s\n", __func__, name);
 	g_dnl_driver.name = name;
 
-	debug("%s: g_dnl_driver.name: %s\n", __func__, g_dnl_driver.name);
-	ret = usb_composite_register(&g_dnl_driver);
-
 	if (ret) {
 		printf("%s: failed!, error: %d\n", __func__, ret);
 		return ret;
 	}
-
 	return 0;
 }
 

include/dfu.h

@@ -168,12 +168,5 @@ static inline int dfu_fill_entity_ram(struct dfu_entity *dfu, char *s)
 }
 #endif
 
-#ifdef CONFIG_DFU_FUNCTION
 int dfu_add(struct usb_configuration *c);
-#else
-int dfu_add(struct usb_configuration *c)
-{
-	return 0;
-}
-#endif
 #endif /* __DFU_ENTITY_H_ */

include/g_dnl.h

@@ -10,6 +10,29 @@
 
 #include <linux/usb/ch9.h>
 #include <linux/usb/gadget.h>
+#include <linux/usb/composite.h>
+#include <linker_lists.h>
+
+/*
+ * @usb_fname: unescaped USB function name
+ * @callback_ptr: bind callback, one per function name
+ */
+#define DECLARE_GADGET_BIND_CALLBACK(usb_fname, callback_ptr) \
+	ll_entry_declare(struct g_dnl_bind_callback, \
+			__usb_function_name_##usb_fname, \
+			g_dnl_bind_callbacks) = { \
+				.usb_function_name = #usb_fname, \
+				.fptr = callback_ptr \
+			}
+
+typedef int (*g_dnl_bind_callback_f)(struct usb_configuration *);
+
+/* used in Gadget downloader callback linker list */
+struct g_dnl_bind_callback {
+	const char *usb_function_name;
+	g_dnl_bind_callback_f fptr;
+};
+
 int g_dnl_bind_fixup(struct usb_device_descriptor *, const char *);
 int g_dnl_board_usb_cable_connected(void);
 int g_dnl_register(const char *s);

include/thor.h

@@ -15,13 +15,5 @@
 
 int thor_handle(void);
 int thor_init(void);
-
-#ifdef CONFIG_THOR_FUNCTION
 int thor_add(struct usb_configuration *c);
-#else
-int thor_add(struct usb_configuration *c)
-{
-	return 0;
-}
-#endif
 #endif /* __THOR_H_ */

include/usb_mass_storage.h

@@ -40,13 +40,5 @@ int fsg_init(struct ums *);
 void fsg_cleanup(void);
 struct ums *ums_init(unsigned int);
 int fsg_main_thread(void *);
-
-#ifdef CONFIG_USB_GADGET_MASS_STORAGE
 int fsg_add(struct usb_configuration *c);
-#else
-int fsg_add(struct usb_configuration *c)
-{
-	return 0;
-}
-#endif
 #endif /* __USB_MASS_STORAGE_H__ */