soc: qcom: QMI encoding/decoding for big endian

[ Upstream commit 3ced38da5f7de4c260f9eaa86fc805827953243a ]

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 <alexander.wilhelm@westermo.com>
Fixes: 9b8a11e82615 ("soc: qcom: Introduce QMI encoder/decoder")
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20250522143530.3623809-2-alexander.wilhelm@westermo.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

1 files changed, 38 insertions, 8 deletions

diff --git a/drivers/soc/qcom/qmi_encdec.c b/drivers/soc/qcom/qmi_encdec.c
index bb09eff85cff..dafe0a4c202e 100644
--- a/drivers/soc/qcom/qmi_encdec.c
+++ b/drivers/soc/qcom/qmi_encdec.c
@@ -304,6 +304,8 @@ static int qmi_encode(const struct qmi_elem_info *ei_array, void *out_buf,
 	const void *buf_src;
 	int encode_tlv = 0;
 	int rc;
+	u8 val8;
+	u16 val16;
 
 	if (!ei_array)
 		return 0;
@@ -338,7 +340,6 @@ static int qmi_encode(const struct qmi_elem_info *ei_array, void *out_buf,
 			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 */
@@ -348,8 +349,17 @@ static int qmi_encode(const struct qmi_elem_info *ei_array, void *out_buf,
 				       __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);
@@ -523,14 +533,23 @@ static int qmi_decode_string_elem(const struct qmi_elem_info *ei_array,
 	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;
 	}
 
@@ -604,6 +623,9 @@ static int qmi_decode(const struct qmi_elem_info *ei_array, void *out_c_struct,
 	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)
@@ -642,9 +664,17 @@ static int qmi_decode(const struct qmi_elem_info *ei_array, void *out_c_struct,
 		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;