NFC: Add a DEP link control netlink command

NFC-DEP (Data Exchange Protocol) is an NFC MAC layer.
This command allows to enable and disable the DEP link on to which e.g.
LLCP can run.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

5 files changed, 255 insertions, 0 deletions

diff --git a/include/linux/nfc.h b/include/linux/nfc.h
index 36cb955b05cc..34d8303111f0 100644
--- a/include/linux/nfc.h
+++ b/include/linux/nfc.h
@@ -62,6 +62,8 @@ enum nfc_commands {
         NFC_CMD_GET_DEVICE,
         NFC_CMD_DEV_UP,
         NFC_CMD_DEV_DOWN,
+        NFC_CMD_DEP_LINK_UP,
+        NFC_CMD_DEP_LINK_DOWN,
         NFC_CMD_START_POLL,
         NFC_CMD_STOP_POLL,
         NFC_CMD_GET_TARGET,
@@ -86,6 +88,8 @@ enum nfc_commands {
  * @NFC_ATTR_TARGET_SENS_RES: NFC-A targets extra information such as NFCID
  * @NFC_ATTR_TARGET_SEL_RES: NFC-A targets extra information (useful if the
  *      target is not NFC-Forum compliant)
+ * @NFC_ATTR_COMM_MODE: Passive or active mode
+ * @NFC_ATTR_RF_MODE: Initiator or target
  */
 enum nfc_attrs {
         NFC_ATTR_UNSPEC,
@@ -95,6 +99,8 @@ enum nfc_attrs {
         NFC_ATTR_TARGET_INDEX,
         NFC_ATTR_TARGET_SENS_RES,
         NFC_ATTR_TARGET_SEL_RES,
+        NFC_ATTR_COMM_MODE,
+        NFC_ATTR_RF_MODE,
 /* private: internal use only */
         __NFC_ATTR_AFTER_LAST
 };
@@ -111,6 +117,14 @@ enum nfc_attrs {
 
 #define NFC_PROTO_MAX           6
 
+/* NFC communication modes */
+#define NFC_COMM_ACTIVE  0
+#define NFC_COMM_PASSIVE 1
+
+/* NFC RF modes */
+#define NFC_RF_INITIATOR 0
+#define NFC_RF_TARGET    1
+
 /* NFC protocols masks used in bitsets */
 #define NFC_PROTO_JEWEL_MASK    (1 << NFC_PROTO_JEWEL)
 #define NFC_PROTO_MIFARE_MASK   (1 << NFC_PROTO_MIFARE)
diff --git a/include/net/nfc/nfc.h b/include/net/nfc/nfc.h
index 3a3304c094d7..bf82d292d68c 100644
--- a/include/net/nfc/nfc.h
+++ b/include/net/nfc/nfc.h
@@ -52,6 +52,9 @@ struct nfc_ops {
         int (*dev_down)(struct nfc_dev *dev);
         int (*start_poll)(struct nfc_dev *dev, u32 protocols);
         void (*stop_poll)(struct nfc_dev *dev);
+        int (*dep_link_up)(struct nfc_dev *dev, int target_idx,
+                                u8 comm_mode, u8 rf_mode);
+        int (*dep_link_down)(struct nfc_dev *dev);
         int (*activate_target)(struct nfc_dev *dev, u32 target_idx,
                                                         u32 protocol);
         void (*deactivate_target)(struct nfc_dev *dev, u32 target_idx);
@@ -60,6 +63,9 @@ struct nfc_ops {
                                                         void *cb_context);
 };
 
+#define NFC_TARGET_IDX_ANY -1
+#define NFC_MAX_GT_LEN 48
+
 struct nfc_target {
         u32 idx;
         u32 supported_protocols;
@@ -83,6 +89,8 @@ struct nfc_dev {
         bool dev_up;
         bool polling;
         bool remote_activated;
+        bool dep_link_up;
+        u32 dep_rf_mode;
         struct nfc_genl_data genl_data;
         u32 supported_protocols;
 
@@ -165,4 +173,7 @@ struct sk_buff *nfc_alloc_recv_skb(unsigned int size, gfp_t gfp);
 int nfc_targets_found(struct nfc_dev *dev, struct nfc_target *targets,
                                                         int ntargets);
 
+int nfc_dep_link_is_up(struct nfc_dev *dev, u32 target_idx,
+                       u8 comm_mode, u8 rf_mode);
+
 #endif /* __NET_NFC_H */
diff --git a/net/nfc/core.c b/net/nfc/core.c
index f53f88ada687..785f1f20c7ba 100644
--- a/net/nfc/core.c
+++ b/net/nfc/core.c
@@ -181,6 +181,83 @@ error:
         return rc;
 }
 
+int nfc_dep_link_up(struct nfc_dev *dev, int target_index,
+                                        u8 comm_mode, u8 rf_mode)
+{
+        int rc = 0;
+
+        pr_debug("dev_name=%s comm:%d rf:%d\n",
+                        dev_name(&dev->dev), comm_mode, rf_mode);
+
+        if (!dev->ops->dep_link_up)
+                return -EOPNOTSUPP;
+
+        device_lock(&dev->dev);
+
+        if (!device_is_registered(&dev->dev)) {
+                rc = -ENODEV;
+                goto error;
+        }
+
+        if (dev->dep_link_up == true) {
+                rc = -EALREADY;
+                goto error;
+        }
+
+        rc = dev->ops->dep_link_up(dev, target_index, comm_mode, rf_mode);
+
+error:
+        device_unlock(&dev->dev);
+        return rc;
+}
+
+int nfc_dep_link_down(struct nfc_dev *dev)
+{
+        int rc = 0;
+
+        pr_debug("dev_name=%s\n", dev_name(&dev->dev));
+
+        if (!dev->ops->dep_link_down)
+                return -EOPNOTSUPP;
+
+        device_lock(&dev->dev);
+
+        if (!device_is_registered(&dev->dev)) {
+                rc = -ENODEV;
+                goto error;
+        }
+
+        if (dev->dep_link_up == false) {
+                rc = -EALREADY;
+                goto error;
+        }
+
+        if (dev->dep_rf_mode == NFC_RF_TARGET) {
+                rc = -EOPNOTSUPP;
+                goto error;
+        }
+
+        rc = dev->ops->dep_link_down(dev);
+        if (!rc) {
+                dev->dep_link_up = false;
+                nfc_genl_dep_link_down_event(dev);
+        }
+
+error:
+        device_unlock(&dev->dev);
+        return rc;
+}
+
+int nfc_dep_link_is_up(struct nfc_dev *dev, u32 target_idx,
+                                        u8 comm_mode, u8 rf_mode)
+{
+        dev->dep_link_up = true;
+        dev->dep_rf_mode = rf_mode;
+
+        return nfc_genl_dep_link_up_event(dev, target_idx, comm_mode, rf_mode);
+}
+EXPORT_SYMBOL(nfc_dep_link_is_up);
+
 /**
  * nfc_activate_target - prepare the target for data exchange
  *
diff --git a/net/nfc/netlink.c b/net/nfc/netlink.c
index 1d76d38c4a24..43a1c47756a7 100644
--- a/net/nfc/netlink.c
+++ b/net/nfc/netlink.c
@@ -46,6 +46,8 @@ static const struct nla_policy nfc_genl_policy[NFC_ATTR_MAX + 1] = {
         [NFC_ATTR_DEVICE_NAME] = { .type = NLA_STRING,
                                 .len = NFC_DEVICE_NAME_MAXSIZE },
         [NFC_ATTR_PROTOCOLS] = { .type = NLA_U32 },
+        [NFC_ATTR_COMM_MODE] = { .type = NLA_U8 },
+        [NFC_ATTR_RF_MODE] = { .type = NLA_U8 },
 };
 
 static int nfc_genl_send_target(struct sk_buff *msg, struct nfc_target *target,
@@ -311,6 +313,75 @@ static int nfc_genl_dump_devices_done(struct netlink_callback *cb)
         return 0;
 }
 
+int nfc_genl_dep_link_up_event(struct nfc_dev *dev, u32 target_idx,
+                                                u8 comm_mode, u8 rf_mode)
+{
+        struct sk_buff *msg;
+        void *hdr;
+
+        pr_debug("DEP link is up\n");
+
+        msg = nlmsg_new(NLMSG_GOODSIZE, GFP_ATOMIC);
+        if (!msg)
+                return -ENOMEM;
+
+        hdr = genlmsg_put(msg, 0, 0, &nfc_genl_family, 0,
+                                NFC_CMD_DEP_LINK_UP);
+        if (!hdr)
+                goto free_msg;
+
+        NLA_PUT_U32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx);
+        if (rf_mode == NFC_RF_INITIATOR)
+                NLA_PUT_U32(msg, NFC_ATTR_TARGET_INDEX, target_idx);
+        NLA_PUT_U8(msg, NFC_ATTR_COMM_MODE, comm_mode);
+        NLA_PUT_U8(msg, NFC_ATTR_RF_MODE, rf_mode);
+
+        genlmsg_end(msg, hdr);
+
+        dev->dep_link_up = true;
+
+        genlmsg_multicast(msg, 0, nfc_genl_event_mcgrp.id, GFP_ATOMIC);
+
+        return 0;
+
+nla_put_failure:
+        genlmsg_cancel(msg, hdr);
+free_msg:
+        nlmsg_free(msg);
+        return -EMSGSIZE;
+}
+
+int nfc_genl_dep_link_down_event(struct nfc_dev *dev)
+{
+        struct sk_buff *msg;
+        void *hdr;
+
+        pr_debug("DEP link is down\n");
+
+        msg = nlmsg_new(NLMSG_GOODSIZE, GFP_ATOMIC);
+        if (!msg)
+                return -ENOMEM;
+
+        hdr = genlmsg_put(msg, 0, 0, &nfc_genl_family, 0,
+                                NFC_CMD_DEP_LINK_DOWN);
+        if (!hdr)
+                goto free_msg;
+
+        NLA_PUT_U32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx);
+
+        genlmsg_end(msg, hdr);
+
+        genlmsg_multicast(msg, 0, nfc_genl_event_mcgrp.id, GFP_ATOMIC);
+
+        return 0;
+
+nla_put_failure:
+        genlmsg_cancel(msg, hdr);
+free_msg:
+        nlmsg_free(msg);
+        return -EMSGSIZE;
+}
+
 static int nfc_genl_get_device(struct sk_buff *skb, struct genl_info *info)
 {
         struct sk_buff *msg;
@@ -398,6 +469,8 @@ static int nfc_genl_start_poll(struct sk_buff *skb, struct genl_info *info)
         u32 idx;
         u32 protocols;
 
+        pr_debug("Poll start\n");
+
         if (!info->attrs[NFC_ATTR_DEVICE_INDEX] ||
                 !info->attrs[NFC_ATTR_PROTOCOLS])
                 return -EINVAL;
@@ -452,6 +525,67 @@ out:
         return rc;
 }
 
+static int nfc_genl_dep_link_up(struct sk_buff *skb, struct genl_info *info)
+{
+        struct nfc_dev *dev;
+        int rc, tgt_idx;
+        u32 idx;
+        u8 comm, rf;
+
+        pr_debug("DEP link up\n");
+
+        if (!info->attrs[NFC_ATTR_DEVICE_INDEX] ||
+                        !info->attrs[NFC_ATTR_COMM_MODE] ||
+                        !info->attrs[NFC_ATTR_RF_MODE])
+                return -EINVAL;
+
+        idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);
+        if (!info->attrs[NFC_ATTR_TARGET_INDEX])
+                tgt_idx = NFC_TARGET_IDX_ANY;
+        else
+                tgt_idx = nla_get_u32(info->attrs[NFC_ATTR_TARGET_INDEX]);
+
+        comm = nla_get_u8(info->attrs[NFC_ATTR_COMM_MODE]);
+        rf = nla_get_u8(info->attrs[NFC_ATTR_RF_MODE]);
+
+        if (comm != NFC_COMM_ACTIVE && comm != NFC_COMM_PASSIVE)
+                return -EINVAL;
+
+        if (rf != NFC_RF_INITIATOR && comm != NFC_RF_TARGET)
+                return -EINVAL;
+
+        dev = nfc_get_device(idx);
+        if (!dev)
+                return -ENODEV;
+
+        rc = nfc_dep_link_up(dev, tgt_idx, comm, rf);
+
+        nfc_put_device(dev);
+
+        return rc;
+}
+
+static int nfc_genl_dep_link_down(struct sk_buff *skb, struct genl_info *info)
+{
+        struct nfc_dev *dev;
+        int rc;
+        u32 idx;
+
+        if (!info->attrs[NFC_ATTR_DEVICE_INDEX])
+                return -EINVAL;
+
+        idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);
+
+        dev = nfc_get_device(idx);
+        if (!dev)
+                return -ENODEV;
+
+        rc = nfc_dep_link_down(dev);
+
+        nfc_put_device(dev);
+        return rc;
+}
+
 static struct genl_ops nfc_genl_ops[] = {
         {
                 .cmd = NFC_CMD_GET_DEVICE,
@@ -481,6 +615,16 @@ static struct genl_ops nfc_genl_ops[] = {
                 .policy = nfc_genl_policy,
         },
         {
+                .cmd = NFC_CMD_DEP_LINK_UP,
+                .doit = nfc_genl_dep_link_up,
+                .policy = nfc_genl_policy,
+        },
+        {
+                .cmd = NFC_CMD_DEP_LINK_DOWN,
+                .doit = nfc_genl_dep_link_down,
+                .policy = nfc_genl_policy,
+        },
+        {
                 .cmd = NFC_CMD_GET_TARGET,
                 .dumpit = nfc_genl_dump_targets,
                 .done = nfc_genl_dump_targets_done,
diff --git a/net/nfc/nfc.h b/net/nfc/nfc.h
index 67d605015304..4d0fb125d033 100644
--- a/net/nfc/nfc.h
+++ b/net/nfc/nfc.h
@@ -68,6 +68,10 @@ int nfc_genl_targets_found(struct nfc_dev *dev);
 int nfc_genl_device_added(struct nfc_dev *dev);
 int nfc_genl_device_removed(struct nfc_dev *dev);
 
+int nfc_genl_dep_link_up_event(struct nfc_dev *dev, u32 target_idx,
+                               u8 comm_mode, u8 rf_mode);
+int nfc_genl_dep_link_down_event(struct nfc_dev *dev);
+
 struct nfc_dev *nfc_get_device(unsigned idx);
 
 static inline void nfc_put_device(struct nfc_dev *dev)
@@ -102,6 +106,11 @@ int nfc_start_poll(struct nfc_dev *dev, u32 protocols);
 
 int nfc_stop_poll(struct nfc_dev *dev);
 
+int nfc_dep_link_up(struct nfc_dev *dev, int target_idx,
+                                u8 comm_mode, u8 rf_mode);
+
+int nfc_dep_link_down(struct nfc_dev *dev);
+
 int nfc_activate_target(struct nfc_dev *dev, u32 target_idx, u32 protocol);
 
 int nfc_deactivate_target(struct nfc_dev *dev, u32 target_idx);