usb: gadget: f_subset: add configfs support

f_subset learns about configfs so we can, eventually,
remove in-kernel gadget drivers.

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-subset b/Documentation/ABI/testing/configfs-usb-gadget-subset
new file mode 100644 (file)
index 0000000..f47170a
--- /dev/null
+++ b/Documentation/ABI/testing/configfs-usb-gadget-subset
@@ -0,0 +1,14 @@
+What:          /config/usb-gadget/gadget/functions/geth.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 0a444f3..3a72b9d 100644 (file)
--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -547,6 +547,16 @@ choice
 
 # this first set of drivers all depend on bulk-capable hardware.
 
+config USB_CONFIGFS_ECM_SUBSET
+       boolean "Ethernet Control Model (CDC ECM) subset"
+       depends on USB_CONFIGFS
+       depends on NET
+       select USB_U_ETHER
+       select USB_F_SUBSET
+       help
+         On hardware that can't implement the full protocol,
+         a simple CDC subset is used, placing fewer demands on USB.
+
 config USB_CONFIGFS_EEM
        bool "Ethernet Emulation Model (EEM)"
        depends on USB_CONFIGFS

diff --git a/drivers/usb/gadget/f_subset.c b/drivers/usb/gadget/f_subset.c
index 089881a..fbc7a24 100644 (file)
--- a/drivers/usb/gadget/f_subset.c
+++ b/drivers/usb/gadget/f_subset.c
@@ -17,6 +17,7 @@
 #include <linux/etherdevice.h>
 
 #include "u_ether.h"
+#include "u_ether_configfs.h"
 #include "u_gether.h"
 
 /*
@@ -313,8 +314,10 @@ geth_bind(struct usb_configuration *c, struct usb_function *f)
         * with regard to gether_opts->bound access
         */
        if (!gether_opts->bound) {
+               mutex_lock(&gether_opts->lock);
                gether_set_gadget(gether_opts->net, cdev->gadget);
                status = gether_register_netdev(gether_opts->net);
+               mutex_unlock(&gether_opts->lock);
                if (status)
                        return status;
                gether_opts->bound = true;
@@ -445,6 +448,41 @@ int geth_bind_config(struct usb_configuration *c, u8 ethaddr[ETH_ALEN],
 
 #else
 
+static inline struct f_gether_opts *to_f_gether_opts(struct config_item *item)
+{
+       return container_of(to_config_group(item), struct f_gether_opts,
+                           func_inst.group);
+}
+
+/* f_gether_item_ops */
+USB_ETHERNET_CONFIGFS_ITEM(gether);
+
+/* f_gether_opts_dev_addr */
+USB_ETHERNET_CONFIGFS_ITEM_ATTR_DEV_ADDR(gether);
+
+/* f_gether_opts_host_addr */
+USB_ETHERNET_CONFIGFS_ITEM_ATTR_HOST_ADDR(gether);
+
+/* f_gether_opts_qmult */
+USB_ETHERNET_CONFIGFS_ITEM_ATTR_QMULT(gether);
+
+/* f_gether_opts_ifname */
+USB_ETHERNET_CONFIGFS_ITEM_ATTR_IFNAME(gether);
+
+static struct configfs_attribute *gether_attrs[] = {
+       &f_gether_opts_dev_addr.attr,
+       &f_gether_opts_host_addr.attr,
+       &f_gether_opts_qmult.attr,
+       &f_gether_opts_ifname.attr,
+       NULL,
+};
+
+static struct config_item_type gether_func_type = {
+       .ct_item_ops    = &gether_item_ops,
+       .ct_attrs       = gether_attrs,
+       .ct_owner       = THIS_MODULE,
+};
+
 static void geth_free_inst(struct usb_function_instance *f)
 {
        struct f_gether_opts *opts;
@@ -464,12 +502,15 @@ static struct usb_function_instance *geth_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 = geth_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, "",
+                                   &gether_func_type);
+
        return &opts->func_inst;
 }
 
@@ -500,6 +541,8 @@ static struct usb_function *geth_alloc(struct usb_function_instance *fi)
 
        opts = container_of(fi, struct f_gether_opts, func_inst);
 
+       mutex_lock(&opts->lock);
+       opts->refcnt++;
        /* export host's Ethernet address in CDC format */
        status = gether_get_host_addr_cdc(opts->net, geth->ethaddr,
                                          sizeof(geth->ethaddr));
@@ -510,6 +553,7 @@ static struct usb_function *geth_alloc(struct usb_function_instance *fi)
        geth_string_defs[1].s = geth->ethaddr;
 
        geth->port.ioport = netdev_priv(opts->net);
+       mutex_unlock(&opts->lock);
        geth->port.cdc_filter = DEFAULT_FILTER;
 
        geth->port.func.name = "cdc_subset";

diff --git a/drivers/usb/gadget/u_gether.h b/drivers/usb/gadget/u_gether.h
index 3a4a2bf..d407842 100644 (file)
--- a/drivers/usb/gadget/u_gether.h
+++ b/drivers/usb/gadget/u_gether.h
@@ -22,6 +22,15 @@ struct f_gether_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_GETHER_H */