[net PATCH 1/2] net: dsa: qca8k: fix inband mgmt for big-endian systems

From: Christian Marangi
Date: Mon Oct 10 2022 - 13:17:32 EST


The header and the data of the skb for the inband mgmt requires
to be in little-endian. This is problematic for big-endian system
as the mgmt header is written in the cpu byte order.

Fix this by converting each value for the mgmt header and data to
little-endian, and convert to cpu byte order the mgmt header and
data sent by the switch.

Fixes: 5950c7c0a68c ("net: dsa: qca8k: add support for mgmt read/write in Ethernet packet")
Tested-by: Pawel Dembicki <paweldembicki@xxxxxxxxx>
Tested-by: Lech Perczak <lech.perczak@xxxxxxxxx>
Signed-off-by: Christian Marangi <ansuelsmth@xxxxxxxxx>
Reviewed-by: Lech Perczak <lech.perczak@xxxxxxxxx>
---
drivers/net/dsa/qca/qca8k-8xxx.c | 63 ++++++++++++++++++++++++--------
include/linux/dsa/tag_qca.h | 6 +--
2 files changed, 50 insertions(+), 19 deletions(-)

diff --git a/drivers/net/dsa/qca/qca8k-8xxx.c b/drivers/net/dsa/qca/qca8k-8xxx.c
index 5669c92c93f7..4bb9b7eac68b 100644
--- a/drivers/net/dsa/qca/qca8k-8xxx.c
+++ b/drivers/net/dsa/qca/qca8k-8xxx.c
@@ -137,27 +137,42 @@ static void qca8k_rw_reg_ack_handler(struct dsa_switch *ds, struct sk_buff *skb)
struct qca8k_mgmt_eth_data *mgmt_eth_data;
struct qca8k_priv *priv = ds->priv;
struct qca_mgmt_ethhdr *mgmt_ethhdr;
+ u32 command;
u8 len, cmd;
+ int i;

mgmt_ethhdr = (struct qca_mgmt_ethhdr *)skb_mac_header(skb);
mgmt_eth_data = &priv->mgmt_eth_data;

- cmd = FIELD_GET(QCA_HDR_MGMT_CMD, mgmt_ethhdr->command);
- len = FIELD_GET(QCA_HDR_MGMT_LENGTH, mgmt_ethhdr->command);
+ command = le32_to_cpu(mgmt_ethhdr->command);
+ cmd = FIELD_GET(QCA_HDR_MGMT_CMD, command);
+ len = FIELD_GET(QCA_HDR_MGMT_LENGTH, command);

/* Make sure the seq match the requested packet */
- if (mgmt_ethhdr->seq == mgmt_eth_data->seq)
+ if (le32_to_cpu(mgmt_ethhdr->seq) == mgmt_eth_data->seq)
mgmt_eth_data->ack = true;

if (cmd == MDIO_READ) {
- mgmt_eth_data->data[0] = mgmt_ethhdr->mdio_data;
+ u32 *val = mgmt_eth_data->data;
+
+ *val = le32_to_cpu(mgmt_ethhdr->mdio_data);

/* Get the rest of the 12 byte of data.
* The read/write function will extract the requested data.
*/
- if (len > QCA_HDR_MGMT_DATA1_LEN)
- memcpy(mgmt_eth_data->data + 1, skb->data,
- QCA_HDR_MGMT_DATA2_LEN);
+ if (len > QCA_HDR_MGMT_DATA1_LEN) {
+ __le32 *data2 = (__le32 *)skb->data;
+ int data_len = min_t(int, QCA_HDR_MGMT_DATA2_LEN,
+ len - QCA_HDR_MGMT_DATA1_LEN);
+
+ val++;
+
+ for (i = sizeof(u32); i <= data_len; i += sizeof(u32)) {
+ *val = le32_to_cpu(*data2);
+ val++;
+ data2++;
+ }
+ }
}

complete(&mgmt_eth_data->rw_done);
@@ -169,8 +184,10 @@ static struct sk_buff *qca8k_alloc_mdio_header(enum mdio_cmd cmd, u32 reg, u32 *
struct qca_mgmt_ethhdr *mgmt_ethhdr;
unsigned int real_len;
struct sk_buff *skb;
- u32 *data2;
+ __le32 *data2;
+ u32 command;
u16 hdr;
+ int i;

skb = dev_alloc_skb(QCA_HDR_MGMT_PKT_LEN);
if (!skb)
@@ -199,20 +216,32 @@ static struct sk_buff *qca8k_alloc_mdio_header(enum mdio_cmd cmd, u32 reg, u32 *
hdr |= FIELD_PREP(QCA_HDR_XMIT_DP_BIT, BIT(0));
hdr |= FIELD_PREP(QCA_HDR_XMIT_CONTROL, QCA_HDR_XMIT_TYPE_RW_REG);

- mgmt_ethhdr->command = FIELD_PREP(QCA_HDR_MGMT_ADDR, reg);
- mgmt_ethhdr->command |= FIELD_PREP(QCA_HDR_MGMT_LENGTH, real_len);
- mgmt_ethhdr->command |= FIELD_PREP(QCA_HDR_MGMT_CMD, cmd);
- mgmt_ethhdr->command |= FIELD_PREP(QCA_HDR_MGMT_CHECK_CODE,
+ command = FIELD_PREP(QCA_HDR_MGMT_ADDR, reg);
+ command |= FIELD_PREP(QCA_HDR_MGMT_LENGTH, real_len);
+ command |= FIELD_PREP(QCA_HDR_MGMT_CMD, cmd);
+ command |= FIELD_PREP(QCA_HDR_MGMT_CHECK_CODE,
QCA_HDR_MGMT_CHECK_CODE_VAL);

+ mgmt_ethhdr->command = cpu_to_le32(command);
+
if (cmd == MDIO_WRITE)
- mgmt_ethhdr->mdio_data = *val;
+ mgmt_ethhdr->mdio_data = cpu_to_le32(*val);

mgmt_ethhdr->hdr = htons(hdr);

data2 = skb_put_zero(skb, QCA_HDR_MGMT_DATA2_LEN + QCA_HDR_MGMT_PADDING_LEN);
- if (cmd == MDIO_WRITE && len > QCA_HDR_MGMT_DATA1_LEN)
- memcpy(data2, val + 1, len - QCA_HDR_MGMT_DATA1_LEN);
+ if (cmd == MDIO_WRITE && len > QCA_HDR_MGMT_DATA1_LEN) {
+ int data_len = min_t(int, QCA_HDR_MGMT_DATA2_LEN,
+ len - QCA_HDR_MGMT_DATA1_LEN);
+
+ val++;
+
+ for (i = sizeof(u32); i <= data_len; i += sizeof(u32)) {
+ *data2 = cpu_to_le32(*val);
+ data2++;
+ val++;
+ }
+ }

return skb;
}
@@ -220,9 +249,11 @@ static struct sk_buff *qca8k_alloc_mdio_header(enum mdio_cmd cmd, u32 reg, u32 *
static void qca8k_mdio_header_fill_seq_num(struct sk_buff *skb, u32 seq_num)
{
struct qca_mgmt_ethhdr *mgmt_ethhdr;
+ u32 seq;

+ seq = FIELD_PREP(QCA_HDR_MGMT_SEQ_NUM, seq_num);
mgmt_ethhdr = (struct qca_mgmt_ethhdr *)skb->data;
- mgmt_ethhdr->seq = FIELD_PREP(QCA_HDR_MGMT_SEQ_NUM, seq_num);
+ mgmt_ethhdr->seq = cpu_to_le32(seq);
}

static int qca8k_read_eth(struct qca8k_priv *priv, u32 reg, u32 *val, int len)
diff --git a/include/linux/dsa/tag_qca.h b/include/linux/dsa/tag_qca.h
index 50be7cbd93a5..0e176da1e43f 100644
--- a/include/linux/dsa/tag_qca.h
+++ b/include/linux/dsa/tag_qca.h
@@ -61,9 +61,9 @@ struct sk_buff;

/* Special struct emulating a Ethernet header */
struct qca_mgmt_ethhdr {
- u32 command; /* command bit 31:0 */
- u32 seq; /* seq 63:32 */
- u32 mdio_data; /* first 4byte mdio */
+ __le32 command; /* command bit 31:0 */
+ __le32 seq; /* seq 63:32 */
+ __le32 mdio_data; /* first 4byte mdio */
__be16 hdr; /* qca hdr */
} __packed;

--
2.37.2