usb: gadget: f_ncm: add configfs support

Add configfs support to the NCM function driver so
that we can, eventually, get rid of kernel-based
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/drivers/usb/gadget/f_ncm.c b/drivers/usb/gadget/f_ncm.c
index effd2fada9251b05ef96183621973ac0dcc7c43d..697262e2a57531ee4cd6b0568f281d524873b6a1 100644 (file)
--- a/drivers/usb/gadget/f_ncm.c
+++ b/drivers/usb/gadget/f_ncm.c
@@ -1175,8 +1175,10 @@ static int ncm_bind(struct usb_configuration *c, struct usb_function *f)
         * with regard to ncm_opts->bound access
         */
        if (!ncm_opts->bound) {
+               mutex_lock(&ncm_opts->lock);
                gether_set_gadget(ncm_opts->net, cdev->gadget);
                status = gether_register_netdev(ncm_opts->net);
+               mutex_unlock(&ncm_opts->lock);
                if (status)
                        return status;
                ncm_opts->bound = true;
@@ -1290,6 +1292,159 @@ fail:
        return status;
 }
 
+static inline struct f_ncm_opts *to_f_ncm_opts(struct config_item *item)
+{
+       return container_of(to_config_group(item), struct f_ncm_opts,
+                           func_inst.group);
+}
+
+CONFIGFS_ATTR_STRUCT(f_ncm_opts);
+CONFIGFS_ATTR_OPS(f_ncm_opts);
+
+static void ncm_attr_release(struct config_item *item)
+{
+       struct f_ncm_opts *opts = to_f_ncm_opts(item);
+
+       usb_put_function_instance(&opts->func_inst);
+}
+
+static struct configfs_item_operations ncm_item_ops = {
+       .release        = ncm_attr_release,
+       .show_attribute = f_ncm_opts_attr_show,
+       .store_attribute = f_ncm_opts_attr_store,
+};
+
+static ssize_t ncm_opts_dev_addr_show(struct f_ncm_opts *opts, char *page)
+{
+       int result;
+
+       mutex_lock(&opts->lock);
+       result = gether_get_dev_addr(opts->net, page, PAGE_SIZE);
+       mutex_unlock(&opts->lock);
+
+       return result;
+}
+
+static ssize_t ncm_opts_dev_addr_store(struct f_ncm_opts *opts,
+               const char *page, size_t len)
+{
+       int ret;
+
+       mutex_lock(&opts->lock);
+       if (opts->refcnt) {
+               mutex_unlock(&opts->lock);
+               return -EBUSY;
+       }
+
+       ret = gether_set_dev_addr(opts->net, page);
+       mutex_unlock(&opts->lock);
+       if (!ret)
+               ret = len;
+       return ret;
+}
+
+static struct f_ncm_opts_attribute f_ncm_opts_dev_addr =
+       __CONFIGFS_ATTR(dev_addr, S_IRUGO | S_IWUSR, ncm_opts_dev_addr_show,
+                       ncm_opts_dev_addr_store);
+
+static ssize_t ncm_opts_host_addr_show(struct f_ncm_opts *opts, char *page)
+{
+       int result;
+
+       mutex_lock(&opts->lock);
+       result = gether_get_host_addr(opts->net, page, PAGE_SIZE);
+       mutex_unlock(&opts->lock);
+
+       return result;
+}
+
+static ssize_t ncm_opts_host_addr_store(struct f_ncm_opts *opts,
+               const char *page, size_t len)
+{
+       int ret;
+
+       mutex_lock(&opts->lock);
+       if (opts->refcnt) {
+               mutex_unlock(&opts->lock);
+               return -EBUSY;
+       }
+
+       ret = gether_set_host_addr(opts->net, page);
+       mutex_unlock(&opts->lock);
+       if (!ret)
+               ret = len;
+       return ret;
+}
+
+static struct f_ncm_opts_attribute f_ncm_opts_host_addr =
+       __CONFIGFS_ATTR(host_addr, S_IRUGO | S_IWUSR, ncm_opts_host_addr_show,
+                       ncm_opts_host_addr_store);
+
+static ssize_t ncm_opts_qmult_show(struct f_ncm_opts *opts, char *page)
+{
+       unsigned qmult;
+
+       mutex_lock(&opts->lock);
+       qmult = gether_get_qmult(opts->net);
+       mutex_unlock(&opts->lock);
+       return sprintf(page, "%d", qmult);
+}
+
+static ssize_t ncm_opts_qmult_store(struct f_ncm_opts *opts,
+               const char *page, size_t len)
+{
+       u8 val;
+       int ret;
+
+       mutex_lock(&opts->lock);
+       if (opts->refcnt) {
+               ret = -EBUSY;
+               goto out;
+       }
+
+       ret = kstrtou8(page, 0, &val);
+       if (ret)
+               goto out;
+
+       gether_set_qmult(opts->net, val);
+       ret = len;
+out:
+       mutex_unlock(&opts->lock);
+       return ret;
+}
+
+static struct f_ncm_opts_attribute f_ncm_opts_qmult =
+       __CONFIGFS_ATTR(qmult, S_IRUGO | S_IWUSR, ncm_opts_qmult_show,
+                       ncm_opts_qmult_store);
+
+static ssize_t ncm_opts_ifname_show(struct f_ncm_opts *opts, char *page)
+{
+       int ret;
+
+       mutex_lock(&opts->lock);
+       ret = gether_get_ifname(opts->net, page, PAGE_SIZE);
+       mutex_unlock(&opts->lock);
+
+       return ret;
+}
+
+static struct f_ncm_opts_attribute f_ncm_opts_ifname =
+       __CONFIGFS_ATTR_RO(ifname, ncm_opts_ifname_show);
+
+static struct configfs_attribute *ncm_attrs[] = {
+       &f_ncm_opts_dev_addr.attr,
+       &f_ncm_opts_host_addr.attr,
+       &f_ncm_opts_qmult.attr,
+       &f_ncm_opts_ifname.attr,
+       NULL,
+};
+
+static struct config_item_type ncm_func_type = {
+       .ct_item_ops    = &ncm_item_ops,
+       .ct_attrs       = ncm_attrs,
+       .ct_owner       = THIS_MODULE,
+};
+
 static void ncm_free_inst(struct usb_function_instance *f)
 {
        struct f_ncm_opts *opts;
@@ -1309,20 +1464,28 @@ static struct usb_function_instance *ncm_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 = ncm_free_inst;
        opts->net = gether_setup_default();
        if (IS_ERR(opts->net))
                return ERR_PTR(PTR_ERR(opts->net));
 
+       config_group_init_type_name(&opts->func_inst.group, "", &ncm_func_type);
+
        return &opts->func_inst;
 }
 
 static void ncm_free(struct usb_function *f)
 {
        struct f_ncm *ncm;
+       struct f_ncm_opts *opts;
 
        ncm = func_to_ncm(f);
+       opts = container_of(f->fi, struct f_ncm_opts, func_inst);
        kfree(ncm);
+       mutex_lock(&opts->lock);
+       opts->refcnt--;
+       mutex_unlock(&opts->lock);
 }
 
 static void ncm_unbind(struct usb_configuration *c, struct usb_function *f)
@@ -1349,6 +1512,8 @@ struct usb_function *ncm_alloc(struct usb_function_instance *fi)
                return ERR_PTR(-ENOMEM);
 
        opts = container_of(fi, struct f_ncm_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, ncm->ethaddr,
@@ -1362,6 +1527,7 @@ struct usb_function *ncm_alloc(struct usb_function_instance *fi)
        spin_lock_init(&ncm->lock);
        ncm_reset_values(ncm);
        ncm->port.ioport = netdev_priv(opts->net);
+       mutex_unlock(&opts->lock);
        ncm->port.is_fixed = true;
 
        ncm->port.func.name = "cdc_network";

diff --git a/drivers/usb/gadget/u_ncm.h b/drivers/usb/gadget/u_ncm.h
index 1e22b5fa844b340005aa51d4db7a49beaecd8d6c..ce0f3a78ca13945299adab1be1faf5c95ab825ad 100644 (file)
--- a/drivers/usb/gadget/u_ncm.h
+++ b/drivers/usb/gadget/u_ncm.h
@@ -22,6 +22,15 @@ struct f_ncm_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_NCM_H */