usb: gadget: f_acm: convert to new function interface with backwards compatibility

This patch converts f_acm into a module which uses the new function
interface. It also converts one of its users that is g_serial to make
use of it. The other users of it (g_nokia for instance) are still using
the old include file system and should not notice the change at all. So
they can be converter later independently.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/Kconfig

@@ -500,6 +500,9 @@ config USB_LIBCOMPOSITE
 	tristate
 	depends on USB_GADGET
 
+config USB_F_ACM
+	tristate
+
 config USB_F_SS_LB
 	tristate
 
@@ -758,6 +761,7 @@ config USB_GADGET_TARGET
 config USB_G_SERIAL
 	tristate "Serial Gadget (with CDC ACM and CDC OBEX support)"
 	select USB_U_SERIAL
+	select USB_F_ACM
 	select USB_LIBCOMPOSITE
 	help
 	  The Serial Gadget talks to the Linux-USB generic serial driver.

drivers/usb/gadget/Makefile

@@ -76,6 +76,7 @@ obj-$(CONFIG_USB_G_ACM_MS)	+= g_acm_ms.o
 obj-$(CONFIG_USB_GADGET_TARGET)	+= tcm_usb_gadget.o
 
 # USB Functions
+obj-$(CONFIG_USB_F_ACM)		+= f_acm.o
 f_ss_lb-y			:= f_loopback.o f_sourcesink.o
 obj-$(CONFIG_USB_F_SS_LB)	+= f_ss_lb.o
 obj-$(CONFIG_USB_U_SERIAL)	+= u_serial.o

drivers/usb/gadget/acm_ms.c

@@ -40,7 +40,7 @@
  * the runtime footprint, and giving us at least some parts of what
  * a "gcc --combine ... part1.c part2.c part3.c ... " build would.
  */
-
+#define USB_FACM_INCLUDED
 #include "f_acm.c"
 #include "f_mass_storage.c"
 

drivers/usb/gadget/cdc2.c

@@ -42,7 +42,7 @@ USB_GADGET_COMPOSITE_OPTIONS();
  * the runtime footprint, and giving us at least some parts of what
  * a "gcc --combine ... part1.c part2.c part3.c ... " build would.
  */
-
+#define USB_FACM_INCLUDED
 #include "f_acm.c"
 #include "f_ecm.c"
 #include "u_ether.c"

drivers/usb/gadget/f_acm.c

@@ -16,7 +16,9 @@
 
 #include <linux/slab.h>
 #include <linux/kernel.h>
+#include <linux/module.h>
 #include <linux/device.h>
+#include <linux/err.h>
 
 #include "u_serial.h"
 #include "gadget_chips.h"
@@ -608,6 +610,22 @@ acm_bind(struct usb_configuration *c, struct usb_function *f)
 	int			status;
 	struct usb_ep		*ep;
 
+	/* REVISIT might want instance-specific strings to help
+	 * distinguish instances ...
+	 */
+
+	/* maybe allocate device-global string IDs, and patch descriptors */
+	if (acm_string_defs[0].id == 0) {
+		status = usb_string_ids_tab(c->cdev, acm_string_defs);
+		if (status < 0)
+			return status;
+		acm_control_interface_desc.iInterface =
+			acm_string_defs[ACM_CTRL_IDX].id;
+		acm_data_interface_desc.iInterface =
+			acm_string_defs[ACM_DATA_IDX].id;
+		acm_iad_descriptor.iFunction = acm_string_defs[ACM_IAD_IDX].id;
+	}
+
 	/* allocate instance-specific interface IDs, and patch descriptors */
 	status = usb_interface_id(c, f);
 	if (status < 0)
@@ -700,13 +718,40 @@ fail:
 	return status;
 }
 
+static struct f_acm *acm_alloc_basic_func(void)
+{
+	struct f_acm	*acm;
+
+	acm = kzalloc(sizeof(*acm), GFP_KERNEL);
+	if (!acm)
+		return NULL;
+
+	spin_lock_init(&acm->lock);
+
+	acm->port.connect = acm_connect;
+	acm->port.disconnect = acm_disconnect;
+	acm->port.send_break = acm_send_break;
+
+	acm->port.func.name = "acm";
+	acm->port.func.strings = acm_strings;
+	/* descriptors are per-instance copies */
+	acm->port.func.bind = acm_bind;
+	acm->port.func.set_alt = acm_set_alt;
+	acm->port.func.setup = acm_setup;
+	acm->port.func.disable = acm_disable;
+
+	return acm;
+}
+
+#ifdef USB_FACM_INCLUDED
 static void
-acm_unbind(struct usb_configuration *c, struct usb_function *f)
+acm_old_unbind(struct usb_configuration *c, struct usb_function *f)
 {
 	struct f_acm		*acm = func_to_acm(f);
 
 	acm_string_defs[0].id = 0;
 	usb_free_all_descriptors(f);
+	if (acm->notify_req)
 		gs_free_req(acm->notify, acm->notify_req);
 	kfree(acm);
 }
@@ -725,46 +770,74 @@ int acm_bind_config(struct usb_configuration *c, u8 port_num)
 	struct f_acm	*acm;
 	int		status;
 
-	/* REVISIT might want instance-specific strings to help
-	 * distinguish instances ...
-	 */
-
-	/* maybe allocate device-global string IDs, and patch descriptors */
-	if (acm_string_defs[0].id == 0) {
-		status = usb_string_ids_tab(c->cdev, acm_string_defs);
-		if (status < 0)
-			return status;
-		acm_control_interface_desc.iInterface =
-			acm_string_defs[ACM_CTRL_IDX].id;
-		acm_data_interface_desc.iInterface =
-			acm_string_defs[ACM_DATA_IDX].id;
-		acm_iad_descriptor.iFunction = acm_string_defs[ACM_IAD_IDX].id;
-	}
-
 	/* allocate and initialize one new instance */
-	acm = kzalloc(sizeof *acm, GFP_KERNEL);
+	acm = acm_alloc_basic_func();
 	if (!acm)
 		return -ENOMEM;
 
-	spin_lock_init(&acm->lock);
-
 	acm->port_num = port_num;
-
-	acm->port.connect = acm_connect;
-	acm->port.disconnect = acm_disconnect;
-	acm->port.send_break = acm_send_break;
-
-	acm->port.func.name = "acm";
-	acm->port.func.strings = acm_strings;
-	/* descriptors are per-instance copies */
-	acm->port.func.bind = acm_bind;
-	acm->port.func.unbind = acm_unbind;
-	acm->port.func.set_alt = acm_set_alt;
-	acm->port.func.setup = acm_setup;
-	acm->port.func.disable = acm_disable;
+	acm->port.func.unbind = acm_old_unbind;
 
 	status = usb_add_function(c, &acm->port.func);
 	if (status)
 		kfree(acm);
 	return status;
 }
+
+#else
+
+static void acm_unbind(struct usb_configuration *c, struct usb_function *f)
+{
+	struct f_acm		*acm = func_to_acm(f);
+
+	acm_string_defs[0].id = 0;
+	usb_free_all_descriptors(f);
+	if (acm->notify_req)
+		gs_free_req(acm->notify, acm->notify_req);
+}
+
+static void acm_free_func(struct usb_function *f)
+{
+	struct f_acm		*acm = func_to_acm(f);
+
+	kfree(acm);
+}
+
+static struct usb_function *acm_alloc_func(struct usb_function_instance *fi)
+{
+	struct f_serial_opts *opts;
+	struct f_acm *acm;
+
+	acm = acm_alloc_basic_func();
+	if (!acm)
+		return ERR_PTR(-ENOMEM);
+
+	opts = container_of(fi, struct f_serial_opts, func_inst);
+	acm->port_num = opts->port_num;
+	acm->port.func.unbind = acm_unbind;
+	acm->port.func.free_func = acm_free_func;
+
+	return &acm->port.func;
+}
+
+static void acm_free_instance(struct usb_function_instance *fi)
+{
+	struct f_serial_opts *opts;
+
+	opts = container_of(fi, struct f_serial_opts, func_inst);
+	kfree(opts);
+}
+
+static struct usb_function_instance *acm_alloc_instance(void)
+{
+	struct f_serial_opts *opts;
+
+	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
+	if (!opts)
+		return ERR_PTR(-ENOMEM);
+	opts->func_inst.free_func_inst = acm_free_instance;
+	return &opts->func_inst;
+}
+DECLARE_USB_FUNCTION_INIT(acm, acm_alloc_instance, acm_alloc_func);
+MODULE_LICENSE("GPL");
+#endif

drivers/usb/gadget/multi.c

@@ -41,7 +41,7 @@ MODULE_LICENSE("GPL");
  * a "gcc --combine ... part1.c part2.c part3.c ... " build would.
  */
 #include "f_mass_storage.c"
-
+#define USB_FACM_INCLUDED
 #include "f_acm.c"
 
 #include "f_ecm.c"

drivers/usb/gadget/nokia.c

@@ -37,6 +37,7 @@
  * the runtime footprint, and giving us at least some parts of what
  * a "gcc --combine ... part1.c part2.c part3.c ... " build would.
  */
+#define USB_FACM_INCLUDED
 #include "f_acm.c"
 #include "f_ecm.c"
 #include "f_obex.c"

drivers/usb/gadget/serial.c

@@ -36,7 +36,6 @@
  * the runtime footprint, and giving us at least some parts of what
  * a "gcc --combine ... part1.c part2.c part3.c ... " build would.
  */
-#include "f_acm.c"
 #include "f_obex.c"
 #include "f_serial.c"
 
@@ -129,16 +128,6 @@ MODULE_PARM_DESC(n_ports, "number of ports to create, default=1");
 /*-------------------------------------------------------------------------*/
 static unsigned char tty_lines[MAX_U_SERIAL_PORTS];
 
-static int __init serial_bind_acm_config(struct usb_configuration *c)
-{
-	unsigned i;
-	int status = 0;
-
-	for (i = 0; i < n_ports && status == 0; i++)
-		status = acm_bind_config(c, tty_lines[i]);
-	return status;
-}
-
 static int __init serial_bind_obex_config(struct usb_configuration *c)
 {
 	unsigned i;
@@ -166,13 +155,58 @@ static struct usb_configuration serial_config_driver = {
 	.bmAttributes	= USB_CONFIG_ATT_SELFPOWER,
 };
 
-static int gs_unbind(struct usb_composite_dev *cdev)
+static struct usb_function_instance *fi_serial[MAX_U_SERIAL_PORTS];
+static struct usb_function *f_serial[MAX_U_SERIAL_PORTS];
+
+static int serial_register_ports(struct usb_composite_dev *cdev,
+		struct usb_configuration *c, const char *f_name)
 {
 	int i;
+	int ret;
+
+	ret = usb_add_config_only(cdev, c);
+	if (ret)
+		goto out;
+
+	for (i = 0; i < n_ports; i++) {
+		struct f_serial_opts *opts;
+
+		fi_serial[i] = usb_get_function_instance(f_name);
+		if (IS_ERR(fi_serial[i])) {
+			ret = PTR_ERR(fi_serial[i]);
+			goto fail;
+		}
+		opts = container_of(fi_serial[i], struct f_serial_opts, func_inst);
+		opts->port_num = tty_lines[i];
+
+		f_serial[i] = usb_get_function(fi_serial[i]);
+		if (IS_ERR(f_serial[i])) {
+			ret = PTR_ERR(f_serial[i]);
+			goto err_get_func;
+		}
+
+		ret = usb_add_function(c, f_serial[i]);
+		if (ret)
+			goto err_add_func;
+	}
 
-	for (i = 0; i < n_ports; i++)
-		gserial_free_line(tty_lines[i]);
 	return 0;
+
+err_add_func:
+	usb_put_function(f_serial[i]);
+err_get_func:
+	usb_put_function_instance(fi_serial[i]);
+
+fail:
+	i--;
+	while (i >= 0) {
+		usb_remove_function(c, f_serial[i]);
+		usb_put_function(f_serial[i]);
+		usb_put_function_instance(fi_serial[i]);
+		i--;
+	}
+out:
+	return ret;
 }
 
 static int __init gs_bind(struct usb_composite_dev *cdev)
@@ -204,10 +238,11 @@ static int __init gs_bind(struct usb_composite_dev *cdev)
 	}
 
 	/* register our configuration */
-	if (use_acm)
-		status = usb_add_config(cdev, &serial_config_driver,
-				serial_bind_acm_config);
-	else if (use_obex)
+	if (use_acm) {
+		status  = serial_register_ports(cdev, &serial_config_driver,
+				"acm");
+		usb_ep_autoconfig_reset(cdev->gadget);
+	} else if (use_obex)
 		status = usb_add_config(cdev, &serial_config_driver,
 				serial_bind_obex_config);
 	else
@@ -228,6 +263,18 @@ fail:
 	return status;
 }
 
+static int gs_unbind(struct usb_composite_dev *cdev)
+{
+	int i;
+
+	for (i = 0; i < n_ports; i++) {
+		usb_put_function(f_serial[i]);
+		usb_put_function_instance(fi_serial[i]);
+		gserial_free_line(tty_lines[i]);
+	}
+	return 0;
+}
+
 static __refdata struct usb_composite_driver gserial_driver = {
 	.name		= "g_serial",
 	.dev		= &device_desc,

drivers/usb/gadget/u_serial.h

@@ -17,6 +17,11 @@
 
 #define MAX_U_SERIAL_PORTS	4
 
+struct f_serial_opts {
+	struct usb_function_instance func_inst;
+	u8 port_num;
+};
+
 /*
  * One non-multiplexed "serial" I/O port ... there can be several of these
  * on any given USB peripheral device, if it provides enough endpoints.