Introduce optional DLC element for Classic CAN helpers

Introduce optional DLC element for Classic CAN helpers

[Marc Kleine-Budde]

Hello,

just picking up the helper functions and the len8_dlc driver support, which are
patches 7 and 8 of Oliver's series.

Changes since v7:
- add prose to commit message
- change arguments of can_get_cc_dlc()
- converted can_get_cc_len() -> can_frame_set_cc_len()

can_frame_set_cc_len()...maybe call it can_frame_set_len

regards,
Marc

[PATCH v7 1/2] can-dev: introduce helpers to access Classical CAN DLC values

[Marc Kleine-Budde]

From: Oliver Hartkopp <socketcan@hartkopp.net>

This patch adds the following helper to functions to access Classical CAN DLC
values.

can_get_cc_dlc(): get the data length code for Classical CAN raw DLC access
can_frame_set_cc_len(): set len and len8_dlc value for Classical CAN raw DLC access

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Link: https://lore.kernel.org/r/20201110101852.1973-8-socketcan@hartkopp.net
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 include/linux/can/dev.h | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h
index e767a96ae075..197a79535cc2 100644
--- a/include/linux/can/dev.h
+++ b/include/linux/can/dev.h
@@ -170,6 +170,31 @@ static inline bool can_is_canfd_skb(const struct sk_buff *skb)
 	return skb->len == CANFD_MTU;
 }
 
+/* helper to get the data length code (DLC) for Classical CAN raw DLC access */
+static inline u8 can_get_cc_dlc(const struct can_frame *cf, const u32 ctrlmode)
+{
+	/* return len8_dlc as dlc value only if all conditions apply */
+	if ((ctrlmode & CAN_CTRLMODE_CC_LEN8_DLC) &&
+	    (cf->len == CAN_MAX_DLEN) &&
+	    (cf->len8_dlc > CAN_MAX_DLEN && cf->len8_dlc <= CAN_MAX_RAW_DLC))
+		return cf->len8_dlc;
+
+	/* return the payload length as dlc value */
+	return cf->len;
+}
+
+/* helper to set len and len8_dlc value for Classical CAN raw DLC access */
+static inline void can_frame_set_cc_len(struct can_frame *cf, const u8 dlc,
+					const u32 ctrlmode)
+{
+	/* the caller already ensured that dlc is a value from 0 .. 15 */
+	if (ctrlmode & CAN_CTRLMODE_CC_LEN8_DLC && dlc > CAN_MAX_DLEN)
+		cf->len8_dlc = dlc;
+
+	/* limit the payload length 'len' to CAN_MAX_DLEN */
+	cf->len = can_cc_dlc2len(dlc);
+}
+
 /* helper to define static CAN controller features at device creation time */
 static inline void can_set_static_ctrlmode(struct net_device *dev,
 					   u32 static_mode)
-- 
2.28.0

[PATCH v7 2/2] can-dev: add len8_dlc support for various CAN USB adapters

[Marc Kleine-Budde]

From: Oliver Hartkopp <socketcan@hartkopp.net>

Support the Classical CAN raw DLC functionality to send and receive DLC
values from 9 .. 15 on various Classical CAN capable USB network drivers:

- gs_usb
- pcan_usb
- pcan_usb_fd
- usb_8dev

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Tested-by: Oliver Hartkopp <socketcan@hartkopp.net>
Link: https://lore.kernel.org/r/20201110101852.1973-9-socketcan@hartkopp.net
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 drivers/net/can/usb/gs_usb.c               |  7 ++++---
 drivers/net/can/usb/peak_usb/pcan_usb.c    |  8 +++++---
 drivers/net/can/usb/peak_usb/pcan_usb_fd.c | 19 +++++++++++++------
 drivers/net/can/usb/usb_8dev.c             |  9 +++++----
 4 files changed, 27 insertions(+), 16 deletions(-)

diff --git a/drivers/net/can/usb/gs_usb.c b/drivers/net/can/usb/gs_usb.c
index 940589667a7f..dc0b9f65bbe3 100644
--- a/drivers/net/can/usb/gs_usb.c
+++ b/drivers/net/can/usb/gs_usb.c
@@ -331,7 +331,7 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
 
 		cf->can_id = hf->can_id;
 
-		cf->len = can_cc_dlc2len(hf->len);
+		can_frame_set_cc_len(cf, hf->len, dev->can.ctrlmode);
 		memcpy(cf->data, hf->data, 8);
 
 		/* ERROR frames tell us information about the controller */
@@ -504,7 +504,8 @@ static netdev_tx_t gs_can_start_xmit(struct sk_buff *skb,
 	cf = (struct can_frame *)skb->data;
 
 	hf->can_id = cf->can_id;
-	hf->len = cf->len;
+	hf->len = can_get_cc_dlc(cf, dev->can.ctrlmode);
+
 	memcpy(hf->data, cf->data, cf->len);
 
 	usb_fill_bulk_urb(urb, dev->udev,
@@ -858,7 +859,7 @@ static struct gs_can *gs_make_candev(unsigned int channel,
 	dev->can.bittiming_const = &dev->bt_const;
 	dev->can.do_set_bittiming = gs_usb_set_bittiming;
 
-	dev->can.ctrlmode_supported = 0;
+	dev->can.ctrlmode_supported = CAN_CTRLMODE_CC_LEN8_DLC;
 
 	if (bt_const->feature & GS_CAN_FEATURE_LISTEN_ONLY)
 		dev->can.ctrlmode_supported |= CAN_CTRLMODE_LISTENONLY;
diff --git a/drivers/net/can/usb/peak_usb/pcan_usb.c b/drivers/net/can/usb/peak_usb/pcan_usb.c
index ec34f87cc02c..e6c1e5d33924 100644
--- a/drivers/net/can/usb/peak_usb/pcan_usb.c
+++ b/drivers/net/can/usb/peak_usb/pcan_usb.c
@@ -734,7 +734,7 @@ static int pcan_usb_decode_data(struct pcan_usb_msg_context *mc, u8 status_len)
 		cf->can_id = le16_to_cpu(tmp16) >> 5;
 	}
 
-	cf->len = can_cc_dlc2len(rec_len);
+	can_frame_set_cc_len(cf, rec_len, mc->pdev->dev.can.ctrlmode);
 
 	/* Only first packet timestamp is a word */
 	if (pcan_usb_decode_ts(mc, !mc->rec_ts_idx))
@@ -838,7 +838,8 @@ static int pcan_usb_encode_msg(struct peak_usb_device *dev, struct sk_buff *skb,
 	pc = obuf + PCAN_USB_MSG_HEADER_LEN;
 
 	/* status/len byte */
-	*pc = cf->len;
+	*pc = can_get_cc_dlc(cf, dev->can.ctrlmode);
+
 	if (cf->can_id & CAN_RTR_FLAG)
 		*pc |= PCAN_USB_STATUSLEN_RTR;
 
@@ -992,7 +993,8 @@ const struct peak_usb_adapter pcan_usb = {
 	.device_id = PCAN_USB_PRODUCT_ID,
 	.ctrl_count = 1,
 	.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES | CAN_CTRLMODE_LISTENONLY |
-			      CAN_CTRLMODE_BERR_REPORTING,
+			      CAN_CTRLMODE_BERR_REPORTING |
+			      CAN_CTRLMODE_CC_LEN8_DLC,
 	.clock = {
 		.freq = PCAN_USB_CRYSTAL_HZ / 2 ,
 	},
diff --git a/drivers/net/can/usb/peak_usb/pcan_usb_fd.c b/drivers/net/can/usb/peak_usb/pcan_usb_fd.c
index 761e78d8e647..b050226adae5 100644
--- a/drivers/net/can/usb/peak_usb/pcan_usb_fd.c
+++ b/drivers/net/can/usb/peak_usb/pcan_usb_fd.c
@@ -499,7 +499,9 @@ static int pcan_usb_fd_decode_canmsg(struct pcan_usb_fd_if *usb_if,
 		if (!skb)
 			return -ENOMEM;
 
-		cfd->len = can_cc_dlc2len(pucan_msg_get_dlc(rm));
+		can_frame_set_cc_len((struct can_frame *)cfd,
+				     pucan_msg_get_dlc(rm),
+				     dev->can.ctrlmode);
 	}
 
 	cfd->can_id = le32_to_cpu(rm->can_id);
@@ -767,7 +769,8 @@ static int pcan_usb_fd_encode_msg(struct peak_usb_device *dev,
 			tx_msg_flags |= PUCAN_MSG_ERROR_STATE_IND;
 	} else {
 		/* CAND 2.0 frames */
-		len = cfd->len;
+		len = can_get_cc_dlc((struct can_frame *)cfd,
+				     dev->can.ctrlmode);
 
 		if (cfd->can_id & CAN_RTR_FLAG)
 			tx_msg_flags |= PUCAN_MSG_RTR;
@@ -1036,7 +1039,8 @@ const struct peak_usb_adapter pcan_usb_fd = {
 	.device_id = PCAN_USBFD_PRODUCT_ID,
 	.ctrl_count = PCAN_USBFD_CHANNEL_COUNT,
 	.ctrlmode_supported = CAN_CTRLMODE_FD |
-			CAN_CTRLMODE_3_SAMPLES | CAN_CTRLMODE_LISTENONLY,
+			CAN_CTRLMODE_3_SAMPLES | CAN_CTRLMODE_LISTENONLY |
+			CAN_CTRLMODE_CC_LEN8_DLC,
 	.clock = {
 		.freq = PCAN_UFD_CRYSTAL_HZ,
 	},
@@ -1108,7 +1112,8 @@ const struct peak_usb_adapter pcan_usb_chip = {
 	.device_id = PCAN_USBCHIP_PRODUCT_ID,
 	.ctrl_count = PCAN_USBFD_CHANNEL_COUNT,
 	.ctrlmode_supported = CAN_CTRLMODE_FD |
-		CAN_CTRLMODE_3_SAMPLES | CAN_CTRLMODE_LISTENONLY,
+		CAN_CTRLMODE_3_SAMPLES | CAN_CTRLMODE_LISTENONLY |
+		CAN_CTRLMODE_CC_LEN8_DLC,
 	.clock = {
 		.freq = PCAN_UFD_CRYSTAL_HZ,
 	},
@@ -1180,7 +1185,8 @@ const struct peak_usb_adapter pcan_usb_pro_fd = {
 	.device_id = PCAN_USBPROFD_PRODUCT_ID,
 	.ctrl_count = PCAN_USBPROFD_CHANNEL_COUNT,
 	.ctrlmode_supported = CAN_CTRLMODE_FD |
-			CAN_CTRLMODE_3_SAMPLES | CAN_CTRLMODE_LISTENONLY,
+			CAN_CTRLMODE_3_SAMPLES | CAN_CTRLMODE_LISTENONLY |
+			CAN_CTRLMODE_CC_LEN8_DLC,
 	.clock = {
 		.freq = PCAN_UFD_CRYSTAL_HZ,
 	},
@@ -1252,7 +1258,8 @@ const struct peak_usb_adapter pcan_usb_x6 = {
 	.device_id = PCAN_USBX6_PRODUCT_ID,
 	.ctrl_count = PCAN_USBPROFD_CHANNEL_COUNT,
 	.ctrlmode_supported = CAN_CTRLMODE_FD |
-			CAN_CTRLMODE_3_SAMPLES | CAN_CTRLMODE_LISTENONLY,
+			CAN_CTRLMODE_3_SAMPLES | CAN_CTRLMODE_LISTENONLY |
+			CAN_CTRLMODE_CC_LEN8_DLC,
 	.clock = {
 		.freq = PCAN_UFD_CRYSTAL_HZ,
 	},
diff --git a/drivers/net/can/usb/usb_8dev.c b/drivers/net/can/usb/usb_8dev.c
index 6517aaeb4bc0..3587bfcee13d 100644
--- a/drivers/net/can/usb/usb_8dev.c
+++ b/drivers/net/can/usb/usb_8dev.c
@@ -470,7 +470,7 @@ static void usb_8dev_rx_can_msg(struct usb_8dev_priv *priv,
 			return;
 
 		cf->can_id = be32_to_cpu(msg->id);
-		cf->len = can_cc_dlc2len(msg->dlc & 0xF);
+		can_frame_set_cc_len(cf, msg->dlc & 0xF, priv->can.ctrlmode);
 
 		if (msg->flags & USB_8DEV_EXTID)
 			cf->can_id |= CAN_EFF_FLAG;
@@ -637,7 +637,7 @@ static netdev_tx_t usb_8dev_start_xmit(struct sk_buff *skb,
 		msg->flags |= USB_8DEV_EXTID;
 
 	msg->id = cpu_to_be32(cf->can_id & CAN_ERR_MASK);
-	msg->dlc = cf->len;
+	msg->dlc = can_get_cc_dlc(cf, priv->can.ctrlmode);
 	memcpy(msg->data, cf->data, cf->len);
 	msg->end = USB_8DEV_DATA_END;
 
@@ -927,8 +927,9 @@ static int usb_8dev_probe(struct usb_interface *intf,
 	priv->can.do_set_mode = usb_8dev_set_mode;
 	priv->can.do_get_berr_counter = usb_8dev_get_berr_counter;
 	priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK |
-				      CAN_CTRLMODE_LISTENONLY |
-				      CAN_CTRLMODE_ONE_SHOT;
+				       CAN_CTRLMODE_LISTENONLY |
+				       CAN_CTRLMODE_ONE_SHOT |
+				       CAN_CTRLMODE_CC_LEN8_DLC;
 
 	netdev->netdev_ops = &usb_8dev_netdev_ops;
 
-- 
2.28.0