usb: gadget: f_ecm: convert to new function interface with backward compatibility

Converting ecm to the new function interface requires converting
the USB ecm's function code and its users.

This patch converts the f_ecm.c to the new function interface.

The file is now compiled into a separate usb_f_ecm.ko module.

The old function interface is provided by means of a preprocessor
conditional directives. After all users are converted, the old interface
can be removed.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

9 files changed, 174 insertions, 14 deletions

diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
index bf7ad7317b5d..6f1afd7553e0 100644
--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -514,6 +514,9 @@ config USB_F_OBEX
 config USB_F_NCM
         tristate
 
+config USB_F_ECM
+        tristate
+
 choice
         tristate "USB Gadget Drivers"
         default USB_ETH
diff --git a/drivers/usb/gadget/Makefile b/drivers/usb/gadget/Makefile
index 34b117eec36e..66152f513afd 100644
--- a/drivers/usb/gadget/Makefile
+++ b/drivers/usb/gadget/Makefile
@@ -50,6 +50,8 @@ u_rndis-y			:= rndis.o
 obj-$(CONFIG_USB_U_RNDIS)       += u_rndis.o
 usb_f_ncm-y                     := f_ncm.o
 obj-$(CONFIG_USB_F_NCM)         += usb_f_ncm.o
+usb_f_ecm-y                     := f_ecm.o
+obj-$(CONFIG_USB_F_ECM)         += usb_f_ecm.o
 
 #
 # USB gadget drivers
diff --git a/drivers/usb/gadget/cdc2.c b/drivers/usb/gadget/cdc2.c
index bffa997fd040..ceedaf7cabc6 100644
--- a/drivers/usb/gadget/cdc2.c
+++ b/drivers/usb/gadget/cdc2.c
@@ -44,6 +44,7 @@ USB_ETHERNET_MODULE_PARAMETERS();
  * the runtime footprint, and giving us at least some parts of what
  * a "gcc --combine ... part1.c part2.c part3.c ... " build would.
  */
+#define USBF_ECM_INCLUDED
 #include "f_ecm.c"
 
 /*-------------------------------------------------------------------------*/
diff --git a/drivers/usb/gadget/ether.c b/drivers/usb/gadget/ether.c
index 6bff24f193a2..862ef656e8a1 100644
--- a/drivers/usb/gadget/ether.c
+++ b/drivers/usb/gadget/ether.c
@@ -102,6 +102,7 @@ static inline bool has_rndis(void)
  * the runtime footprint, and giving us at least some parts of what
  * a "gcc --combine ... part1.c part2.c part3.c ... " build would.
  */
+#define USBF_ECM_INCLUDED
 #include "f_ecm.c"
 #include "f_subset.c"
 #ifdef  USB_ETH_RNDIS
diff --git a/drivers/usb/gadget/f_ecm.c b/drivers/usb/gadget/f_ecm.c
index abf8a31ae146..1b5aeb280d4b 100644
--- a/drivers/usb/gadget/f_ecm.c
+++ b/drivers/usb/gadget/f_ecm.c
@@ -14,10 +14,12 @@
 
 #include <linux/slab.h>
 #include <linux/kernel.h>
+#include <linux/module.h>
 #include <linux/device.h>
 #include <linux/etherdevice.h>
 
 #include "u_ether.h"
+#include "u_ecm.h"
 
 
 /*
@@ -687,6 +689,40 @@ ecm_bind(struct usb_configuration *c, struct usb_function *f)
         int                     status;
         struct usb_ep           *ep;
 
+#ifndef USBF_ECM_INCLUDED
+        struct f_ecm_opts       *ecm_opts;
+
+        if (!can_support_ecm(cdev->gadget))
+                return -EINVAL;
+
+        ecm_opts = container_of(f->fi, struct f_ecm_opts, func_inst);
+
+        /*
+         * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
+         * configurations are bound in sequence with list_for_each_entry,
+         * in each configuration its functions are bound in sequence
+         * with list_for_each_entry, so we assume no race condition
+         * with regard to ecm_opts->bound access
+         */
+        if (!ecm_opts->bound) {
+                gether_set_gadget(ecm_opts->net, cdev->gadget);
+                status = gether_register_netdev(ecm_opts->net);
+                if (status)
+                        return status;
+                ecm_opts->bound = true;
+        }
+#endif
+        if (ecm_string_defs[0].id == 0) {
+                status = usb_string_ids_tab(c->cdev, ecm_string_defs);
+                if (status)
+                        return status;
+
+                ecm_control_intf.iInterface = ecm_string_defs[0].id;
+                ecm_data_intf.iInterface = ecm_string_defs[2].id;
+                ecm_desc.iMACAddress = ecm_string_defs[1].id;
+                ecm_iad_descriptor.iFunction = ecm_string_defs[3].id;
+        }
+
         /* allocate instance-specific interface IDs */
         status = usb_interface_id(c, f);
         if (status < 0)
@@ -796,8 +832,10 @@ fail:
         return status;
 }
 
+#ifdef USBF_ECM_INCLUDED
+
 static void
-ecm_unbind(struct usb_configuration *c, struct usb_function *f)
+ecm_old_unbind(struct usb_configuration *c, struct usb_function *f)
 {
         struct f_ecm            *ecm = func_to_ecm(f);
 
@@ -834,17 +872,6 @@ ecm_bind_config(struct usb_configuration *c, u8 ethaddr[ETH_ALEN],
         if (!can_support_ecm(c->cdev->gadget) || !ethaddr)
                 return -EINVAL;
 
-        if (ecm_string_defs[0].id == 0) {
-                status = usb_string_ids_tab(c->cdev, ecm_string_defs);
-                if (status)
-                        return status;
-
-                ecm_control_intf.iInterface = ecm_string_defs[0].id;
-                ecm_data_intf.iInterface = ecm_string_defs[2].id;
-                ecm_desc.iMACAddress = ecm_string_defs[1].id;
-                ecm_iad_descriptor.iFunction = ecm_string_defs[3].id;
-        }
-
         /* allocate and initialize one new instance */
         ecm = kzalloc(sizeof *ecm, GFP_KERNEL);
         if (!ecm)
@@ -861,7 +888,7 @@ ecm_bind_config(struct usb_configuration *c, u8 ethaddr[ETH_ALEN],
         ecm->port.func.strings = ecm_strings;
         /* descriptors are per-instance copies */
         ecm->port.func.bind = ecm_bind;
-        ecm->port.func.unbind = ecm_unbind;
+        ecm->port.func.unbind = ecm_old_unbind;
         ecm->port.func.set_alt = ecm_set_alt;
         ecm->port.func.get_alt = ecm_get_alt;
         ecm->port.func.setup = ecm_setup;
@@ -872,3 +899,99 @@ ecm_bind_config(struct usb_configuration *c, u8 ethaddr[ETH_ALEN],
                 kfree(ecm);
         return status;
 }
+
+#else
+
+static void ecm_free_inst(struct usb_function_instance *f)
+{
+        struct f_ecm_opts *opts;
+
+        opts = container_of(f, struct f_ecm_opts, func_inst);
+        if (opts->bound)
+                gether_cleanup(netdev_priv(opts->net));
+        else
+                free_netdev(opts->net);
+        kfree(opts);
+}
+
+static struct usb_function_instance *ecm_alloc_inst(void)
+{
+        struct f_ecm_opts *opts;
+
+        opts = kzalloc(sizeof(*opts), GFP_KERNEL);
+        if (!opts)
+                return ERR_PTR(-ENOMEM);
+
+        opts->func_inst.free_func_inst = ecm_free_inst;
+        opts->net = gether_setup_default();
+        if (IS_ERR(opts->net))
+                return ERR_PTR(PTR_ERR(opts->net));
+
+        return &opts->func_inst;
+}
+
+static void ecm_free(struct usb_function *f)
+{
+        struct f_ecm *ecm;
+
+        ecm = func_to_ecm(f);
+        kfree(ecm);
+}
+
+static void ecm_unbind(struct usb_configuration *c, struct usb_function *f)
+{
+        struct f_ecm            *ecm = func_to_ecm(f);
+
+        DBG(c->cdev, "ecm unbind\n");
+
+        ecm_string_defs[0].id = 0;
+        usb_free_all_descriptors(f);
+
+        kfree(ecm->notify_req->buf);
+        usb_ep_free_request(ecm->notify, ecm->notify_req);
+}
+
+struct usb_function *ecm_alloc(struct usb_function_instance *fi)
+{
+        struct f_ecm    *ecm;
+        struct f_ecm_opts *opts;
+        int status;
+
+        /* allocate and initialize one new instance */
+        ecm = kzalloc(sizeof(*ecm), GFP_KERNEL);
+        if (!ecm)
+                return ERR_PTR(-ENOMEM);
+
+        opts = container_of(fi, struct f_ecm_opts, func_inst);
+
+        /* export host's Ethernet address in CDC format */
+        status = gether_get_host_addr_cdc(opts->net, ecm->ethaddr,
+                                          sizeof(ecm->ethaddr));
+        if (status < 12) {
+                kfree(ecm);
+                return ERR_PTR(-EINVAL);
+        }
+        ecm_string_defs[1].s = ecm->ethaddr;
+
+        ecm->port.ioport = netdev_priv(opts->net);
+        ecm->port.cdc_filter = DEFAULT_FILTER;
+
+        ecm->port.func.name = "cdc_ethernet";
+        ecm->port.func.strings = ecm_strings;
+        /* descriptors are per-instance copies */
+        ecm->port.func.bind = ecm_bind;
+        ecm->port.func.unbind = ecm_unbind;
+        ecm->port.func.set_alt = ecm_set_alt;
+        ecm->port.func.get_alt = ecm_get_alt;
+        ecm->port.func.setup = ecm_setup;
+        ecm->port.func.disable = ecm_disable;
+        ecm->port.func.free_func = ecm_free;
+
+        return &ecm->port.func;
+}
+
+DECLARE_USB_FUNCTION_INIT(ecm, ecm_alloc_inst, ecm_alloc);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("David Brownell");
+
+#endif
diff --git a/drivers/usb/gadget/g_ffs.c b/drivers/usb/gadget/g_ffs.c
index fbfdb53a2db5..d38a073efd5d 100644
--- a/drivers/usb/gadget/g_ffs.c
+++ b/drivers/usb/gadget/g_ffs.c
@@ -28,6 +28,7 @@
 #    define USB_ETH_RNDIS y
 #  endif
 
+#define USBF_ECM_INCLUDED
 #  include "f_ecm.c"
 #  include "f_subset.c"
 #  ifdef USB_ETH_RNDIS
diff --git a/drivers/usb/gadget/multi.c b/drivers/usb/gadget/multi.c
index ce21e9f8203e..61643938d36b 100644
--- a/drivers/usb/gadget/multi.c
+++ b/drivers/usb/gadget/multi.c
@@ -43,6 +43,7 @@ MODULE_LICENSE("GPL");
  */
 #include "f_mass_storage.c"
 
+#define USBF_ECM_INCLUDED
 #include "f_ecm.c"
 #include "f_subset.c"
 #ifdef USB_ETH_RNDIS
diff --git a/drivers/usb/gadget/nokia.c b/drivers/usb/gadget/nokia.c
index 39f6cb5f984d..8e42c88b453b 100644
--- a/drivers/usb/gadget/nokia.c
+++ b/drivers/usb/gadget/nokia.c
@@ -37,8 +37,9 @@
  * the runtime footprint, and giving us at least some parts of what
  * a "gcc --combine ... part1.c part2.c part3.c ... " build would.
  */
-#define USBF_OBEX_INCLUDED
+#define USBF_ECM_INCLUDED
 #include "f_ecm.c"
+#define USBF_OBEX_INCLUDED
 #include "f_obex.c"
 #include "f_phonet.c"
 #include "u_ether.h"
diff --git a/drivers/usb/gadget/u_ecm.h b/drivers/usb/gadget/u_ecm.h
new file mode 100644
index 000000000000..99b6b995988f
--- /dev/null
+++ b/drivers/usb/gadget/u_ecm.h
@@ -0,0 +1,27 @@
+/*
+ * u_ecm.h
+ *
+ * Utility definitions for the ecm function
+ *
+ * Copyright (c) 2013 Samsung Electronics Co., Ltd.
+ *              http://www.samsung.com
+ *
+ * Author: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef U_ECM_H
+#define U_ECM_H
+
+#include <linux/usb/composite.h>
+
+struct f_ecm_opts {
+        struct usb_function_instance    func_inst;
+        struct net_device               *net;
+        bool                            bound;
+};
+
+#endif /* U_ECM_H */