NFC: netlink: Implement vendor command supporttopic/vendor-cmd

Vendor commands are passed from userspace through the
NFC_CMD_VENDOR netlink command, allowing driver and hardware
specific operations implementations like for example RF tuning
or production line calibration.

Drivers will associate a set of vendor commands to a vendor
id, which could typically be an OUI. The netlink kernel
implementation will try to match the received vendor id
and sub command attributes with the registered ones. When
such match is found, the driver defined sub command routine
is called.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

2 files changed, 59 insertions, 0 deletions

diff --git a/include/uapi/linux/nfc.h b/include/uapi/linux/nfc.h
index 9b19b446192866..af43399649ce66 100644
--- a/include/uapi/linux/nfc.h
+++ b/include/uapi/linux/nfc.h
@@ -86,6 +86,8 @@
  *	for this event is the application ID (AID).
  * @NFC_CMD_GET_SE: Dump all discovered secure elements from an NFC controller.
  * @NFC_CMD_SE_IO: Send/Receive APDUs to/from the selected secure element.
+ * @NFC_CMD_VENDOR: Vendor specific command, to be implemented directly
+ *	from the driver in order to support hardware specific operations.
  */
 enum nfc_commands {
 	NFC_CMD_UNSPEC,
@@ -116,6 +118,7 @@ enum nfc_commands {
 	NFC_EVENT_SE_TRANSACTION,
 	NFC_CMD_GET_SE,
 	NFC_CMD_SE_IO,
+	NFC_CMD_VENDOR,
 /* private: internal use only */
 	__NFC_CMD_AFTER_LAST
 };
@@ -152,6 +155,10 @@ enum nfc_commands {
  * @NFC_ATTR_APDU: Secure element APDU
  * @NFC_ATTR_TARGET_ISO15693_DSFID: ISO 15693 Data Storage Format Identifier
  * @NFC_ATTR_TARGET_ISO15693_UID: ISO 15693 Unique Identifier
+ * @NFC_ATTR_VENDOR_ID: NFC manufacturer unique ID, typically an OUI
+ * @NFC_ATTR_VENDOR_SUBCMD: Vendor specific sub command
+ * @NFC_ATTR_VENDOR_DATA: Vendor specific data, to be optionally passed
+ *	to a vendor specific command implementation
  */
 enum nfc_attrs {
 	NFC_ATTR_UNSPEC,
@@ -182,6 +189,9 @@ enum nfc_attrs {
 	NFC_ATTR_SE_APDU,
 	NFC_ATTR_TARGET_ISO15693_DSFID,
 	NFC_ATTR_TARGET_ISO15693_UID,
+	NFC_ATTR_VENDOR_ID,
+	NFC_ATTR_VENDOR_SUBCMD,
+	NFC_ATTR_VENDOR_DATA,
 /* private: internal use only */
 	__NFC_ATTR_AFTER_LAST
 };
diff --git a/net/nfc/netlink.c b/net/nfc/netlink.c
index 43cb1c17e267d0..179dad0c17cdea 100644
--- a/net/nfc/netlink.c
+++ b/net/nfc/netlink.c
@@ -1370,6 +1370,50 @@ static int nfc_genl_se_io(struct sk_buff *skb, struct genl_info *info)
 	return dev->ops->se_io(dev, se_idx, apdu, apdu_len, se_io_cb, ctx);
 }
 
+static int nfc_genl_vendor_cmd(struct sk_buff *skb,
+			       struct genl_info *info)
+{
+	struct nfc_dev *dev;
+	struct nfc_vendor_cmd *cmd;
+	u32 dev_idx, vid, subcmd;
+	u8 *data;
+	size_t data_len;
+	int i;
+
+	if (!info->attrs[NFC_ATTR_DEVICE_INDEX] ||
+	    !info->attrs[NFC_ATTR_VENDOR_ID] ||
+	    !info->attrs[NFC_ATTR_VENDOR_SUBCMD])
+		return -EINVAL;
+
+	dev_idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);
+	vid = nla_get_u32(info->attrs[NFC_ATTR_VENDOR_ID]);
+	subcmd = nla_get_u32(info->attrs[NFC_ATTR_VENDOR_SUBCMD]);
+
+	dev = nfc_get_device(dev_idx);
+	if (!dev || !dev->vendor_cmds || !dev->n_vendor_cmds)
+		return -ENODEV;
+
+	data = nla_data(info->attrs[NFC_ATTR_VENDOR_DATA]);
+	if (data) {
+		data_len = nla_len(info->attrs[NFC_ATTR_VENDOR_DATA]);
+		if (data_len == 0)
+			return -EINVAL;
+	} else {
+		data_len = 0;
+	}
+
+	for (i = 0; i < dev->n_vendor_cmds; i++) {
+		cmd = &dev->vendor_cmds[i];
+
+		if (cmd->vendor_id != vid || cmd->subcmd != subcmd)
+			continue;
+
+		return cmd->cmd(dev, data, data_len);
+	}
+
+	return -EOPNOTSUPP;
+}
+
 static const struct genl_ops nfc_genl_ops[] = {
 	{
 		.cmd = NFC_CMD_GET_DEVICE,
@@ -1455,6 +1499,11 @@ static const struct genl_ops nfc_genl_ops[] = {
 		.doit = nfc_genl_se_io,
 		.policy = nfc_genl_policy,
 	},
+	{
+		.cmd = NFC_CMD_VENDOR,
+		.doit = nfc_genl_vendor_cmd,
+		.policy = nfc_genl_policy,
+	},
 };