diff --git a/drivers/net/can/at91_can.c b/drivers/net/can/at91_can.c
index cbe3fce53e3b108df0be08b4e96929438289516e..d0ec17878ffc0ff80df1a55a34f2558c30bc8540 100644
--- a/drivers/net/can/at91_can.c
+++ b/drivers/net/can/at91_can.c
@@ -474,7 +474,7 @@ static void at91_read_mb(struct net_device *dev, unsigned int mb,
reg_msr = at91_read(priv, AT91_MSR(mb));
if (reg_msr & AT91_MSR_MRTR)
cf->can_id |= CAN_RTR_FLAG;
- cf->can_dlc = min_t(__u8, (reg_msr >> 16) & 0xf, 8);
+ cf->can_dlc = get_can_dlc((reg_msr >> 16) & 0xf);
*(u32 *)(cf->data + 0) = at91_read(priv, AT91_MDL(mb));
*(u32 *)(cf->data + 4) = at91_read(priv, AT91_MDH(mb));
diff --git a/drivers/net/can/bfin_can.c b/drivers/net/can/bfin_can.c
index c7fc1de28173527157711881666067fc20cb996b..0ec1524523ccaa939988d3d0c1f55bcd3450114f 100644
--- a/drivers/net/can/bfin_can.c
+++ b/drivers/net/can/bfin_can.c
@@ -392,7 +392,7 @@ static void bfin_can_rx(struct net_device *dev, u16 isrc)
cf->can_id |= CAN_RTR_FLAG;
/* get data length code */
- cf->can_dlc = bfin_read16(®->chl[obj].dlc);
+ cf->can_dlc = get_can_dlc(bfin_read16(®->chl[obj].dlc) & 0xF);
/* get payload */
for (i = 0; i < 8; i += 2) {
diff --git a/drivers/net/can/mcp251x.c b/drivers/net/can/mcp251x.c
index 78b1b69b29211d8dc6a0d365839b22e191bcb215..9c5a1537939ce5c5ce4a3f6950686c66389ea1a3 100644
--- a/drivers/net/can/mcp251x.c
+++ b/drivers/net/can/mcp251x.c
@@ -403,9 +403,8 @@ static void mcp251x_hw_rx_frame(struct spi_device *spi, u8 *buf,
for (i = 1; i < RXBDAT_OFF; i++)
buf[i] = mcp251x_read_reg(spi, RXBCTRL(buf_idx) + i);
- len = buf[RXBDLC_OFF] & RXBDLC_LEN_MASK;
- if (len > 8)
- len = 8;
+
+ len = get_can_dlc(buf[RXBDLC_OFF] & RXBDLC_LEN_MASK);
for (; i < (RXBDAT_OFF + len); i++)
buf[i] = mcp251x_read_reg(spi, RXBCTRL(buf_idx) + i);
} else {
@@ -455,13 +454,7 @@ static void mcp251x_hw_rx(struct spi_device *spi, int buf_idx)
(buf[RXBSIDL_OFF] >> RXBSIDL_SHIFT);
}
/* Data length */
- frame->can_dlc = buf[RXBDLC_OFF] & RXBDLC_LEN_MASK;
- if (frame->can_dlc > 8) {
- dev_warn(&spi->dev, "invalid frame recevied\n");
- priv->net->stats.rx_errors++;
- dev_kfree_skb(skb);
- return;
- }
+ frame->can_dlc = get_can_dlc(buf[RXBDLC_OFF] & RXBDLC_LEN_MASK);
memcpy(frame->data, buf + RXBDAT_OFF, frame->can_dlc);
priv->net->stats.rx_packets++;
diff --git a/drivers/net/can/mscan/mscan.c b/drivers/net/can/mscan/mscan.c
index bb06dfb58f2541bb60fff71e84ff2d7042f78cfd..07346f880ca680e49668f7dc783bf734b5dbd157 100644
--- a/drivers/net/can/mscan/mscan.c
+++ b/drivers/net/can/mscan/mscan.c
@@ -297,7 +297,8 @@ static void mscan_get_rx_frame(struct net_device *dev, struct can_frame *frame)
frame->can_id |= can_id >> 1;
if (can_id & 1)
frame->can_id |= CAN_RTR_FLAG;
- frame->can_dlc = in_8(®s->rx.dlr) & 0xf;
+
+ frame->can_dlc = get_can_dlc(in_8(®s->rx.dlr) & 0xf);
if (!(frame->can_id & CAN_RTR_FLAG)) {
void __iomem *data = ®s->rx.dsr1_0;
diff --git a/drivers/net/can/sja1000/sja1000.c b/drivers/net/can/sja1000/sja1000.c
index b4ba88a3107571b65c53ecdae9011b7f6bd8a1c1..542a4f7255b4f5db367ef755abb623aed752c9b1 100644
--- a/drivers/net/can/sja1000/sja1000.c
+++ b/drivers/net/can/sja1000/sja1000.c
@@ -293,15 +293,14 @@ static void sja1000_rx(struct net_device *dev)
uint8_t fi;
uint8_t dreg;
canid_t id;
- uint8_t dlc;
int i;
+ /* create zero'ed CAN frame buffer */
skb = alloc_can_skb(dev, &cf);
if (skb == NULL)
return;
fi = priv->read_reg(priv, REG_FI);
- dlc = fi & 0x0F;
if (fi & FI_FF) {
/* extended frame format (EFF) */
@@ -318,16 +317,15 @@ static void sja1000_rx(struct net_device *dev)
| (priv->read_reg(priv, REG_ID2) >> 5);
}
- if (fi & FI_RTR)
+ if (fi & FI_RTR) {
id |= CAN_RTR_FLAG;
+ } else {
+ cf->can_dlc = get_can_dlc(fi & 0x0F);
+ for (i = 0; i < cf->can_dlc; i++)
+ cf->data[i] = priv->read_reg(priv, dreg++);
+ }
cf->can_id = id;
- cf->can_dlc = dlc;
- for (i = 0; i < dlc; i++)
- cf->data[i] = priv->read_reg(priv, dreg++);
-
- while (i < 8)
- cf->data[i++] = 0;
/* release receive buffer */
priv->write_reg(priv, REG_CMR, CMD_RRB);
@@ -335,7 +333,7 @@ static void sja1000_rx(struct net_device *dev)
netif_rx(skb);
stats->rx_packets++;
- stats->rx_bytes += dlc;
+ stats->rx_bytes += cf->can_dlc;
}
static int sja1000_err(struct net_device *dev, uint8_t isrc, uint8_t status)
diff --git a/drivers/net/can/ti_hecc.c b/drivers/net/can/ti_hecc.c
index 07e8016b17eca24f79e9e862f73d5f85e8ce4e94..5c993c2da5281b24c74434ad54ccb0862fa9bc72 100644
--- a/drivers/net/can/ti_hecc.c
+++ b/drivers/net/can/ti_hecc.c
@@ -552,7 +552,7 @@ static int ti_hecc_rx_pkt(struct ti_hecc_priv *priv, int mbxno)
data = hecc_read_mbx(priv, mbxno, HECC_CANMCF);
if (data & HECC_CANMCF_RTR)
cf->can_id |= CAN_RTR_FLAG;
- cf->can_dlc = data & 0xF;
+ cf->can_dlc = get_can_dlc(data & 0xF);
data = hecc_read_mbx(priv, mbxno, HECC_CANMDL);
*(u32 *)(cf->data) = cpu_to_be32(data);
if (cf->can_dlc > 4) {
diff --git a/drivers/net/can/usb/ems_usb.c b/drivers/net/can/usb/ems_usb.c
index 591eb0eb1c2bdcc5ec147173a41829bd497c093b..efbb05c71bf47fdde6af69fb13d1a38fdd80f032 100644
--- a/drivers/net/can/usb/ems_usb.c
+++ b/drivers/net/can/usb/ems_usb.c
@@ -316,7 +316,7 @@ static void ems_usb_rx_can_msg(struct ems_usb *dev, struct ems_cpc_msg *msg)
return;
cf->can_id = le32_to_cpu(msg->msg.can_msg.id);
- cf->can_dlc = min_t(u8, msg->msg.can_msg.length, 8);
+ cf->can_dlc = get_can_dlc(msg->msg.can_msg.length & 0xF);
if (msg->type == CPC_MSG_TYPE_EXT_CAN_FRAME ||
msg->type == CPC_MSG_TYPE_EXT_RTR_FRAME)
diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h
index 1ed2a5cc03f5fb00dca89368b0d72cd42b85acf9..3db7767d2a175b9caf61ec4d98de415f7c24f6b6 100644
--- a/include/linux/can/dev.h
+++ b/include/linux/can/dev.h
@@ -51,6 +51,15 @@ struct can_priv {
struct sk_buff **echo_skb;
};
+/*
+ * get_can_dlc(value) - helper macro to cast a given data length code (dlc)
+ * to __u8 and ensure the dlc value to be max. 8 bytes.
+ *
+ * To be used in the CAN netdriver receive path to ensure conformance with
+ * ISO 11898-1 Chapter 8.4.2.3 (DLC field)
+ */
+#define get_can_dlc(i) (min_t(__u8, (i), 8))
+
struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max);
void free_candev(struct net_device *dev);