Re: [PATCH v4 5/6] nfc: s3fwrn5: support the S3NRN4V variant

+/*
+ * S3NRN4V RF calibration data update: the HW and SW blobs merged into one
+ * stream (HW first), pushed as START_UPDATE, one SET_OPTION per 252-byte
+ * section, then STOP_UPDATE carrying a 16-bit checksum (running sum of the
+ * merged stream as 32-bit words).
+ */
+int s3fwrn5_nci_rf_configure_dual(struct s3fwrn5_info *info,
+				  const char *hw_name, const char *sw_name)
+{
+	struct nci_prop_dual_set_option_cmd set_option;
+	struct device *dev = &info->ndev->nfc_dev->dev;
+	const struct firmware *hw_fw, *sw_fw;
+	size_t merged_size, i, len;
+	u8 *merged = NULL;
+	u8 stop_cmd[3];
+	u32 checksum;
+	u8 sub_oid;
+	int ret;
+
+	ret = firmware_request_nowarn(&hw_fw, hw_name, dev);
+	if (ret < 0)
+		return ret;
+	ret = firmware_request_nowarn(&sw_fw, sw_name, dev);
+	if (ret < 0)
+		goto out_hw;
+
+	merged_size = hw_fw->size + sw_fw->size;
+
+	/*
+	 * The stream is checksummed as 32-bit words and pushed in at most 256
+	 * sections (the section index is a single byte); reject blobs that
+	 * would silently break either.
+	 */
+	if (!merged_size || merged_size % 4 ||
+	    merged_size > 256 * NCI_PROP_DUAL_SECTION_SIZE) {
+		dev_err(dev, "invalid calibration data size: %zu\n", merged_size);
+		ret = -EINVAL;
+		goto out;

+	}
+
+	/*
+	 * Ask the chip for its current calibration versions and skip the
+	 * upload when both already match the blobs; a mismatch or an
+	 * unparseable answer means the upload proceeds. GET_VER answers with
+	 * versions, not a status byte, so nci_prop_cmd()'s return carries no
+	 * meaning here.
+	 */
+	sub_oid = NCI_PROP_DUAL_SUB_GET_VER;
+	info->dual_rsp_len = 0;
+	nci_prop_cmd(info->ndev, NCI_PROP_DUAL_OPTION, 1, &sub_oid);
+	if (s3fwrn5_nci_dual_cal_current(info, hw_fw, sw_fw)) {
+		dev_dbg(dev, "calibration data already current\n");
+		ret = 0;
+		goto out;

+	}
+
+	merged = kvmalloc(merged_size, GFP_KERNEL);
+	if (!merged) {
+		ret = -ENOMEM;
+		goto out;
+	}
+	memcpy(merged, hw_fw->data, hw_fw->size);
+	memcpy(merged + hw_fw->size, sw_fw->data, sw_fw->size);
+
+	checksum = 0;
+	for (i = 0; i + 4 <= merged_size; i += 4)
+		checksum += get_unaligned_le32(merged + i);
+
+	dev_info(dev, "calibration data update: %s + %s\n", hw_name, sw_name);

+
+	/* START_UPDATE */
+	sub_oid = NCI_PROP_DUAL_SUB_START_UPDATE;
+	ret = nci_prop_cmd(info->ndev, NCI_PROP_DUAL_OPTION, 1, &sub_oid);
+	if (ret < 0) {
+		dev_err(dev, "Unable to start calibration data update\n");
+		goto out;
+	}
+
+	/* SET_OPTION per section */
+	set_option.sub_oid = NCI_PROP_DUAL_SUB_SET_OPTION;
+	set_option.index = 0;
+	for (i = 0; i < merged_size; i += NCI_PROP_DUAL_SECTION_SIZE) {
+		len = min_t(size_t, merged_size - i, NCI_PROP_DUAL_SECTION_SIZE);
+		memcpy(set_option.data, merged + i, len);
+		ret = nci_prop_cmd(info->ndev, NCI_PROP_DUAL_OPTION,
+				   len + 2, (__u8 *)&set_option);
+		if (ret < 0) {
+			dev_err(dev, "calibration data update error: %d\n",
+				ret);
+			/* Abort form: STOP_UPDATE with the sub-OID alone. */
+			sub_oid = NCI_PROP_DUAL_SUB_STOP_UPDATE;
+			nci_prop_cmd(info->ndev, NCI_PROP_DUAL_OPTION, 1,
+				     &sub_oid);
+			goto out;
+		}
+		set_option.index++;
+	}
+
+	/* STOP_UPDATE with checksum */
+	stop_cmd[0] = NCI_PROP_DUAL_SUB_STOP_UPDATE;
+	put_unaligned_le16(checksum, &stop_cmd[1]);
+	ret = nci_prop_cmd(info->ndev, NCI_PROP_DUAL_OPTION, 3, stop_cmd);
+	if (ret < 0) {
+		dev_err(dev, "Unable to stop calibration data update\n");
+		goto out;
+	}
+
+	dev_info(dev, "calibration data update: success\n");

+out:
+	kvfree(merged);
+	release_firmware(sw_fw);
+out_hw:
+	release_firmware(hw_fw);
+	return ret;