soc: qcom: QMI encoding/decoding for big endian

The QMI_DATA_LEN type may have different sizes. Taking the element's
address of that type and interpret it as a smaller sized ones works fine
for little endian platforms but not for big endian ones. Instead use
temporary variables of smaller sized types and cast them correctly to
support big endian platforms.

Signed-off-by: Alexander Wilhelm <[e-mail]>
Fixes: 9b8a11e82615 ("soc: qcom: Introduce QMI encoder/decoder")
Reviewed-by: Dmitry Baryshkov <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Bjorn Andersson <[e-mail]>

drivers/soc/qcom/qmi_encdec.c

···
 	const void *buf_src;
 	int encode_tlv = 0;
 	int rc;
+	u8 val8;
+	u16 val16;
 
 	if (!ei_array)
 		return 0;
···
 			break;
 
 		case QMI_DATA_LEN:
-			memcpy(&data_len_value, buf_src, temp_ei->elem_size);
 			data_len_sz = temp_ei->elem_size == sizeof(u8) ?
 					sizeof(u8) : sizeof(u16);
 			/* Check to avoid out of range buffer access */
···
 				       __func__);
 				return -ETOOSMALL;
 			}
-			rc = qmi_encode_basic_elem(buf_dst, &data_len_value,
-						   1, data_len_sz);
+			if (data_len_sz == sizeof(u8)) {
+				val8 = *(u8 *)buf_src;
+				data_len_value = (u32)val8;
+				rc = qmi_encode_basic_elem(buf_dst, &val8,
+							   1, data_len_sz);
+			} else {
+				val16 = *(u16 *)buf_src;
+				data_len_value = (u32)le16_to_cpu(val16);
+				rc = qmi_encode_basic_elem(buf_dst, &val16,
+							   1, data_len_sz);
+			}
 			UPDATE_ENCODE_VARIABLES(temp_ei, buf_dst,
 						encoded_bytes, tlv_len,
 						encode_tlv, rc);
···
 	u32 string_len = 0;
 	u32 string_len_sz = 0;
 	const struct qmi_elem_info *temp_ei = ei_array;
+	u8 val8;
+	u16 val16;
 
 	if (dec_level == 1) {
 		string_len = tlv_len;
 	} else {
 		string_len_sz = temp_ei->elem_len <= U8_MAX ?
 				sizeof(u8) : sizeof(u16);
-		rc = qmi_decode_basic_elem(&string_len, buf_src,
-					   1, string_len_sz);
+		if (string_len_sz == sizeof(u8)) {
+			rc = qmi_decode_basic_elem(&val8, buf_src,
+						   1, string_len_sz);
+			string_len = (u32)val8;
+		} else {
+			rc = qmi_decode_basic_elem(&val16, buf_src,
+						   1, string_len_sz);
+			string_len = (u32)val16;
+		}
 		decoded_bytes += rc;
 	}
 
···
 	u32 decoded_bytes = 0;
 	const void *buf_src = in_buf;
 	int rc;
+	u8 val8;
+	u16 val16;
+	u32 val32;
 
 	while (decoded_bytes < in_buf_len) {
 		if (dec_level >= 2 && temp_ei->data_type == QMI_EOTI)
···
 		if (temp_ei->data_type == QMI_DATA_LEN) {
 			data_len_sz = temp_ei->elem_size == sizeof(u8) ?
 					sizeof(u8) : sizeof(u16);
-			rc = qmi_decode_basic_elem(&data_len_value, buf_src,
-						   1, data_len_sz);
-			memcpy(buf_dst, &data_len_value, sizeof(u32));
+			if (data_len_sz == sizeof(u8)) {
+				rc = qmi_decode_basic_elem(&val8, buf_src,
+							   1, data_len_sz);
+				data_len_value = (u32)val8;
+			} else {
+				rc = qmi_decode_basic_elem(&val16, buf_src,
+							   1, data_len_sz);
+				data_len_value = (u32)val16;
+			}
+			val32 = cpu_to_le32(data_len_value);
+			memcpy(buf_dst, &val32, sizeof(u32));
 			temp_ei = temp_ei + 1;
 			buf_dst = out_c_struct + temp_ei->offset;
 			tlv_len -= data_len_sz;