NFC: Add firmware upload netlink command

As several NFC chipsets can have their firmwares upgraded and
reflashed, this patchset adds a new netlink command to trigger
that the driver loads or flashes a new firmware. This will allows
userspace triggered firmware upgrade through netlink.
The firmware name or hint is passed as a parameter, and the driver
will eventually fetch the firmware binary through the request_firmware
API.
The cmd can only be executed when the nfc dev is not in use. Actual
firmware loading/flashing is an asynchronous operation. Result of the
operation shall send a new event up to user space through the nfc dev
multicast socket. During operation, the nfc dev is not openable and
thus not usable.

Signed-off-by: Eric Lapuyade <[email protected]>
Signed-off-by: Samuel Ortiz <[email protected]>

Author: Eric Lapuyade

include/net/nfc/nfc.h

@@ -70,6 +70,7 @@ struct nfc_ops {
 	int (*check_presence)(struct nfc_dev *dev, struct nfc_target *target);
 	int (*enable_se)(struct nfc_dev *dev, u32 secure_element);
 	int (*disable_se)(struct nfc_dev *dev, u32 secure_element);
+	int (*fw_upload)(struct nfc_dev *dev, const char *firmware_name);
 };
 
 #define NFC_TARGET_IDX_ANY -1
@@ -104,6 +105,7 @@ struct nfc_dev {
 	int targets_generation;
 	struct device dev;
 	bool dev_up;
+	bool fw_upload_in_progress;
 	u8 rf_mode;
 	bool polling;
 	struct nfc_target *active_target;

include/uapi/linux/nfc.h

@@ -69,6 +69,8 @@
  *	starting a poll from a device which has a secure element enabled means
  *	we want to do SE based card emulation.
  * @NFC_CMD_DISABLE_SE: Disable the physical link to a specific secure element.
+ * @NFC_CMD_FW_UPLOAD: Request to Load/flash firmware, or event to inform that
+ *	some firmware was loaded
  */
 enum nfc_commands {
 	NFC_CMD_UNSPEC,
@@ -92,6 +94,7 @@ enum nfc_commands {
 	NFC_CMD_DISABLE_SE,
 	NFC_CMD_LLC_SDREQ,
 	NFC_EVENT_LLC_SDRES,
+	NFC_CMD_FW_UPLOAD,
 /* private: internal use only */
 	__NFC_CMD_AFTER_LAST
 };
@@ -121,6 +124,7 @@ enum nfc_commands {
  * @NFC_ATTR_LLC_PARAM_RW: Receive Window size parameter
  * @NFC_ATTR_LLC_PARAM_MIUX: MIU eXtension parameter
  * @NFC_ATTR_SE: Available Secure Elements
+ * @NFC_ATTR_FIRMWARE_NAME: Free format firmware version
  */
 enum nfc_attrs {
 	NFC_ATTR_UNSPEC,
@@ -143,6 +147,7 @@ enum nfc_attrs {
 	NFC_ATTR_LLC_PARAM_MIUX,
 	NFC_ATTR_SE,
 	NFC_ATTR_LLC_SDP,
+	NFC_ATTR_FIRMWARE_NAME,
 /* private: internal use only */
 	__NFC_ATTR_AFTER_LAST
 };
@@ -162,6 +167,7 @@ enum nfc_sdp_attr {
 #define NFC_SENSB_RES_MAXSIZE 12
 #define NFC_SENSF_RES_MAXSIZE 18
 #define NFC_GB_MAXSIZE        48
+#define NFC_FIRMWARE_NAME_MAXSIZE 32
 
 /* NFC protocols */
 #define NFC_PROTO_JEWEL		1

net/nfc/core.c

@@ -44,6 +44,47 @@ DEFINE_MUTEX(nfc_devlist_mutex);
 /* NFC device ID bitmap */
 static DEFINE_IDA(nfc_index_ida);
 
+int nfc_fw_upload(struct nfc_dev *dev, const char *firmware_name)
+{
+	int rc = 0;
+
+	pr_debug("%s do firmware %s\n", dev_name(&dev->dev), firmware_name);
+
+	device_lock(&dev->dev);
+
+	if (!device_is_registered(&dev->dev)) {
+		rc = -ENODEV;
+		goto error;
+	}
+
+	if (dev->dev_up) {
+		rc = -EBUSY;
+		goto error;
+	}
+
+	if (!dev->ops->fw_upload) {
+		rc = -EOPNOTSUPP;
+		goto error;
+	}
+
+	dev->fw_upload_in_progress = true;
+	rc = dev->ops->fw_upload(dev, firmware_name);
+	if (rc)
+		dev->fw_upload_in_progress = false;
+
+error:
+	device_unlock(&dev->dev);
+	return rc;
+}
+
+int nfc_fw_upload_done(struct nfc_dev *dev, const char *firmware_name)
+{
+	dev->fw_upload_in_progress = false;
+
+	return nfc_genl_fw_upload_done(dev, firmware_name);
+}
+EXPORT_SYMBOL(nfc_fw_upload_done);
+
 /**
  * nfc_dev_up - turn on the NFC device
  *
@@ -69,6 +110,11 @@ int nfc_dev_up(struct nfc_dev *dev)
 		goto error;
 	}
 
+	if (dev->fw_upload_in_progress) {
+		rc = -EBUSY;
+		goto error;
+	}
+
 	if (dev->dev_up) {
 		rc = -EALREADY;
 		goto error;

net/nfc/netlink.c

@@ -56,6 +56,8 @@ static const struct nla_policy nfc_genl_policy[NFC_ATTR_MAX + 1] = {
 	[NFC_ATTR_LLC_PARAM_RW] = { .type = NLA_U8 },
 	[NFC_ATTR_LLC_PARAM_MIUX] = { .type = NLA_U16 },
 	[NFC_ATTR_LLC_SDP] = { .type = NLA_NESTED },
+	[NFC_ATTR_FIRMWARE_NAME] = { .type = NLA_STRING,
+				     .len = NFC_FIRMWARE_NAME_MAXSIZE },
 };
 
 static const struct nla_policy nfc_sdp_genl_policy[NFC_SDP_ATTR_MAX + 1] = {
@@ -1025,6 +1027,62 @@ static int nfc_genl_llc_sdreq(struct sk_buff *skb, struct genl_info *info)
 	return rc;
 }
 
+static int nfc_genl_fw_upload(struct sk_buff *skb, struct genl_info *info)
+{
+	struct nfc_dev *dev;
+	int rc;
+	u32 idx;
+	char firmware_name[NFC_FIRMWARE_NAME_MAXSIZE + 1];
+
+	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;
+
+	nla_strlcpy(firmware_name, info->attrs[NFC_ATTR_FIRMWARE_NAME],
+		    sizeof(firmware_name));
+
+	rc = nfc_fw_upload(dev, firmware_name);
+
+	nfc_put_device(dev);
+	return rc;
+}
+
+int nfc_genl_fw_upload_done(struct nfc_dev *dev, const char *firmware_name)
+{
+	struct sk_buff *msg;
+	void *hdr;
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	hdr = genlmsg_put(msg, 0, 0, &nfc_genl_family, 0,
+			  NFC_CMD_FW_UPLOAD);
+	if (!hdr)
+		goto free_msg;
+
+	if (nla_put_string(msg, NFC_ATTR_FIRMWARE_NAME, firmware_name) ||
+	    nla_put_u32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx))
+		goto nla_put_failure;
+
+	genlmsg_end(msg, hdr);
+
+	genlmsg_multicast(msg, 0, nfc_genl_event_mcgrp.id, GFP_KERNEL);
+
+	return 0;
+
+nla_put_failure:
+	genlmsg_cancel(msg, hdr);
+free_msg:
+	nlmsg_free(msg);
+	return -EMSGSIZE;
+}
+
 static struct genl_ops nfc_genl_ops[] = {
 	{
 		.cmd = NFC_CMD_GET_DEVICE,
@@ -1084,6 +1142,11 @@ static struct genl_ops nfc_genl_ops[] = {
 		.doit = nfc_genl_llc_sdreq,
 		.policy = nfc_genl_policy,
 	},
+	{
+		.cmd = NFC_CMD_FW_UPLOAD,
+		.doit = nfc_genl_fw_upload,
+		.policy = nfc_genl_policy,
+	},
 };
 
 

net/nfc/nfc.h

@@ -120,6 +120,11 @@ static inline void nfc_device_iter_exit(struct class_dev_iter *iter)
 	class_dev_iter_exit(iter);
 }
 
+int nfc_fw_upload(struct nfc_dev *dev, const char *firmware_name);
+int nfc_genl_fw_upload_done(struct nfc_dev *dev, const char *firmware_name);
+
+int nfc_fw_upload_done(struct nfc_dev *dev, const char *firmware_name);
+
 int nfc_dev_up(struct nfc_dev *dev);
 
 int nfc_dev_down(struct nfc_dev *dev);