usb: gadget: f_eem: add configfs support

f_eem learns about our configfs interface so we
can remove in-kernel gadget drivers in future.

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>

diff --git a/Documentation/ABI/testing/configfs-usb-gadget-eem b/Documentation/ABI/testing/configfs-usb-gadget-eem
new file mode 100644 (file)
index 0000000..10e87d6
--- /dev/null
+++ b/Documentation/ABI/testing/configfs-usb-gadget-eem
@@ -0,0 +1,14 @@
+What:          /config/usb-gadget/gadget/functions/eem.name
+Date:          May 2013
+KenelVersion:  3.11
+Description:
+               The attributes:
+
+               ifname          - network device interface name associated with
+                               this function instance
+               qmult           - queue length multiplier for high and
+                               super speed
+               host_addr       - MAC address of host's end of this
+                               Ethernet over USB link
+               dev_addr        - MAC address of device's end of this
+                               Ethernet over USB link

diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
index 159393d58912a9ee55d4864d4097e092294b3bd6..d5b0ffe2611884d728126315470b042fc3b8eac2 100644 (file)
--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -544,6 +544,21 @@ choice
 
 # this first set of drivers all depend on bulk-capable hardware.
 
+config USB_CONFIGFS_EEM
+       bool "Ethernet Emulation Model (EEM)"
+       depends on USB_CONFIGFS
+       depends on NET
+       select USB_U_ETHER
+       select USB_F_EEM
+       help
+         CDC EEM is a newer USB standard that is somewhat simpler than CDC ECM
+         and therefore can be supported by more hardware.  Technically ECM and
+         EEM are designed for different applications.  The ECM model extends
+         the network interface to the target (e.g. a USB cable modem), and the
+         EEM model is for mobile devices to communicate with hosts using
+         ethernet over USB.  For Linux gadgets, however, the interface with
+         the host is the same (a usbX device), so the differences are minimal.
+
 config USB_CONFIGFS_PHONET
        boolean "Phonet protocol"
        depends on USB_CONFIGFS

diff --git a/drivers/usb/gadget/f_eem.c b/drivers/usb/gadget/f_eem.c
index 31a2cb7ebe82a870876606048d0b3fbba31413e6..90ee8022e8d80c29fbff9a1298d62c13ec869b42 100644 (file)
--- a/drivers/usb/gadget/f_eem.c
+++ b/drivers/usb/gadget/f_eem.c
@@ -19,6 +19,7 @@
 #include <linux/slab.h>
 
 #include "u_ether.h"
+#include "u_ether_configfs.h"
 #include "u_eem.h"
 
 #define EEM_HLEN 2
@@ -263,8 +264,10 @@ static int eem_bind(struct usb_configuration *c, struct usb_function *f)
         * with regard to eem_opts->bound access
         */
        if (!eem_opts->bound) {
+               mutex_lock(&eem_opts->lock);
                gether_set_gadget(eem_opts->net, cdev->gadget);
                status = gether_register_netdev(eem_opts->net);
+               mutex_unlock(&eem_opts->lock);
                if (status)
                        return status;
                eem_opts->bound = true;
@@ -533,6 +536,41 @@ error:
        return status;
 }
 
+static inline struct f_eem_opts *to_f_eem_opts(struct config_item *item)
+{
+       return container_of(to_config_group(item), struct f_eem_opts,
+                           func_inst.group);
+}
+
+/* f_eem_item_ops */
+USB_ETHERNET_CONFIGFS_ITEM(eem);
+
+/* f_eem_opts_dev_addr */
+USB_ETHERNET_CONFIGFS_ITEM_ATTR_DEV_ADDR(eem);
+
+/* f_eem_opts_host_addr */
+USB_ETHERNET_CONFIGFS_ITEM_ATTR_HOST_ADDR(eem);
+
+/* f_eem_opts_qmult */
+USB_ETHERNET_CONFIGFS_ITEM_ATTR_QMULT(eem);
+
+/* f_eem_opts_ifname */
+USB_ETHERNET_CONFIGFS_ITEM_ATTR_IFNAME(eem);
+
+static struct configfs_attribute *eem_attrs[] = {
+       &f_eem_opts_dev_addr.attr,
+       &f_eem_opts_host_addr.attr,
+       &f_eem_opts_qmult.attr,
+       &f_eem_opts_ifname.attr,
+       NULL,
+};
+
+static struct config_item_type eem_func_type = {
+       .ct_item_ops    = &eem_item_ops,
+       .ct_attrs       = eem_attrs,
+       .ct_owner       = THIS_MODULE,
+};
+
 static void eem_free_inst(struct usb_function_instance *f)
 {
        struct f_eem_opts *opts;
@@ -552,20 +590,28 @@ static struct usb_function_instance *eem_alloc_inst(void)
        opts = kzalloc(sizeof(*opts), GFP_KERNEL);
        if (!opts)
                return ERR_PTR(-ENOMEM);
+       mutex_init(&opts->lock);
        opts->func_inst.free_func_inst = eem_free_inst;
        opts->net = gether_setup_default();
        if (IS_ERR(opts->net))
                return ERR_CAST(opts->net);
 
+       config_group_init_type_name(&opts->func_inst.group, "", &eem_func_type);
+
        return &opts->func_inst;
 }
 
 static void eem_free(struct usb_function *f)
 {
        struct f_eem *eem;
+       struct f_eem_opts *opts;
 
        eem = func_to_eem(f);
+       opts = container_of(f->fi, struct f_eem_opts, func_inst);
        kfree(eem);
+       mutex_lock(&opts->lock);
+       opts->refcnt--;
+       mutex_unlock(&opts->lock);
 }
 
 static void eem_unbind(struct usb_configuration *c, struct usb_function *f)
@@ -586,8 +632,11 @@ struct usb_function *eem_alloc(struct usb_function_instance *fi)
                return ERR_PTR(-ENOMEM);
 
        opts = container_of(fi, struct f_eem_opts, func_inst);
+       mutex_lock(&opts->lock);
+       opts->refcnt++;
 
        eem->port.ioport = netdev_priv(opts->net);
+       mutex_unlock(&opts->lock);
        eem->port.cdc_filter = DEFAULT_FILTER;
 
        eem->port.func.name = "cdc_eem";

diff --git a/drivers/usb/gadget/u_eem.h b/drivers/usb/gadget/u_eem.h
index 8f432f2a5e571a76f1e2ad73212dfd07765f1a1a..e3ae97874c4fc0464b428b8bcccb237bc5cee19c 100644 (file)
--- a/drivers/usb/gadget/u_eem.h
+++ b/drivers/usb/gadget/u_eem.h
@@ -22,6 +22,15 @@ struct f_eem_opts {
        struct usb_function_instance    func_inst;
        struct net_device               *net;
        bool                            bound;
+
+       /*
+        * Read/write access to configfs attributes is handled by configfs.
+        *
+        * This is to protect the data from concurrent access by read/write
+        * and create symlink/remove symlink.
+        */
+       struct mutex                    lock;
+       int                             refcnt;
 };
 
 #endif /* U_EEM_H */