can: dev: move length related code into seperate file

This patch moves all CAN frame length related code of the CAN device
infrastructure into a separate file.

Reviewed-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Link: https://lore.kernel.org/r/20210111141930.693847-5-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

6 files changed, 89 insertions, 73 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index d17662df1cd7..21780c4e2e71 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3946,6 +3946,7 @@ F:	drivers/net/can/
 F:	include/linux/can/bittiming.h
 F:	include/linux/can/dev.h
 F:	include/linux/can/led.h
+F:	include/linux/can/length.h
 F:	include/linux/can/platform/
 F:	include/linux/can/rx-offload.h
 F:	include/uapi/linux/can/error.h
diff --git a/drivers/net/can/dev/Makefile b/drivers/net/can/dev/Makefile
index b5c6bb848d9d..5c647951e06d 100644
--- a/drivers/net/can/dev/Makefile
+++ b/drivers/net/can/dev/Makefile
@@ -3,6 +3,7 @@
 obj-$(CONFIG_CAN_DEV)		+= can-dev.o
 can-dev-y			+= bittiming.o
 can-dev-y			+= dev.o
+can-dev-y			+= length.o
 can-dev-y			+= rx-offload.o
 
 can-dev-$(CONFIG_CAN_LEDS)	+= led.o
diff --git a/drivers/net/can/dev/dev.c b/drivers/net/can/dev/dev.c
index 1b3ab95b3fd1..3372e99d5db7 100644
--- a/drivers/net/can/dev/dev.c
+++ b/drivers/net/can/dev/dev.c
@@ -25,39 +25,6 @@ MODULE_DESCRIPTION(MOD_DESC);
 MODULE_LICENSE("GPL v2");
 MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
 
-/* CAN DLC to real data length conversion helpers */
-
-static const u8 dlc2len[] = {0, 1, 2, 3, 4, 5, 6, 7,
-			     8, 12, 16, 20, 24, 32, 48, 64};
-
-/* get data length from raw data length code (DLC) */
-u8 can_fd_dlc2len(u8 dlc)
-{
-	return dlc2len[dlc & 0x0F];
-}
-EXPORT_SYMBOL_GPL(can_fd_dlc2len);
-
-static const u8 len2dlc[] = {0, 1, 2, 3, 4, 5, 6, 7, 8,		/* 0 - 8 */
-			     9, 9, 9, 9,			/* 9 - 12 */
-			     10, 10, 10, 10,			/* 13 - 16 */
-			     11, 11, 11, 11,			/* 17 - 20 */
-			     12, 12, 12, 12,			/* 21 - 24 */
-			     13, 13, 13, 13, 13, 13, 13, 13,	/* 25 - 32 */
-			     14, 14, 14, 14, 14, 14, 14, 14,	/* 33 - 40 */
-			     14, 14, 14, 14, 14, 14, 14, 14,	/* 41 - 48 */
-			     15, 15, 15, 15, 15, 15, 15, 15,	/* 49 - 56 */
-			     15, 15, 15, 15, 15, 15, 15, 15};	/* 57 - 64 */
-
-/* map the sanitized data length to an appropriate data length code */
-u8 can_fd_len2dlc(u8 len)
-{
-	if (unlikely(len > 64))
-		return 0xF;
-
-	return len2dlc[len];
-}
-EXPORT_SYMBOL_GPL(can_fd_len2dlc);
-
 static void can_update_state_error_stats(struct net_device *dev,
 					 enum can_state new_state)
 {
diff --git a/drivers/net/can/dev/length.c b/drivers/net/can/dev/length.c
new file mode 100644
index 000000000000..6fe18aa23ec9
--- /dev/null
+++ b/drivers/net/can/dev/length.c
@@ -0,0 +1,38 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (C) 2012, 2020 Oliver Hartkopp <socketcan@hartkopp.net>
+ */
+
+#include <linux/can/dev.h>
+
+/* CAN DLC to real data length conversion helpers */
+
+static const u8 dlc2len[] = {0, 1, 2, 3, 4, 5, 6, 7,
+			     8, 12, 16, 20, 24, 32, 48, 64};
+
+/* get data length from raw data length code (DLC) */
+u8 can_fd_dlc2len(u8 dlc)
+{
+	return dlc2len[dlc & 0x0F];
+}
+EXPORT_SYMBOL_GPL(can_fd_dlc2len);
+
+static const u8 len2dlc[] = {0, 1, 2, 3, 4, 5, 6, 7, 8,		/* 0 - 8 */
+			     9, 9, 9, 9,			/* 9 - 12 */
+			     10, 10, 10, 10,			/* 13 - 16 */
+			     11, 11, 11, 11,			/* 17 - 20 */
+			     12, 12, 12, 12,			/* 21 - 24 */
+			     13, 13, 13, 13, 13, 13, 13, 13,	/* 25 - 32 */
+			     14, 14, 14, 14, 14, 14, 14, 14,	/* 33 - 40 */
+			     14, 14, 14, 14, 14, 14, 14, 14,	/* 41 - 48 */
+			     15, 15, 15, 15, 15, 15, 15, 15,	/* 49 - 56 */
+			     15, 15, 15, 15, 15, 15, 15, 15};	/* 57 - 64 */
+
+/* map the sanitized data length to an appropriate data length code */
+u8 can_fd_len2dlc(u8 len)
+{
+	if (unlikely(len > 64))
+		return 0xF;
+
+	return len2dlc[len];
+}
+EXPORT_SYMBOL_GPL(can_fd_len2dlc);
diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h
index 054c3bed190b..d75fba1d030a 100644
--- a/include/linux/can/dev.h
+++ b/include/linux/can/dev.h
@@ -18,6 +18,7 @@
 #include <linux/can/bittiming.h>
 #include <linux/can/error.h>
 #include <linux/can/led.h>
+#include <linux/can/length.h>
 #include <linux/can/netlink.h>
 #include <linux/can/skb.h>
 #include <linux/netdevice.h>
@@ -83,15 +84,6 @@ struct can_priv {
 #endif
 };
 
-/*
- * can_cc_dlc2len(value) - convert a given data length code (dlc) of a
- * Classical CAN frame into a valid data length of 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 can_cc_dlc2len(dlc)	(min_t(u8, (dlc), CAN_MAX_DLEN))
-
 /* Check for outgoing skbs that have not been created by the CAN subsystem */
 static inline bool can_skb_headroom_valid(struct net_device *dev,
 					  struct sk_buff *skb)
@@ -156,31 +148,6 @@ 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)
@@ -196,12 +163,6 @@ static inline void can_set_static_ctrlmode(struct net_device *dev,
 		dev->mtu = CANFD_MTU;
 }
 
-/* get data length from raw data length code (DLC) */
-u8 can_fd_dlc2len(u8 dlc);
-
-/* map the sanitized data length to an appropriate data length code */
-u8 can_fd_len2dlc(u8 len);
-
 struct net_device *alloc_candev_mqs(int sizeof_priv, unsigned int echo_skb_max,
 				    unsigned int txqs, unsigned int rxqs);
 #define alloc_candev(sizeof_priv, echo_skb_max) \
diff --git a/include/linux/can/length.h b/include/linux/can/length.h
new file mode 100644
index 000000000000..156b9d17969a
--- /dev/null
+++ b/include/linux/can/length.h
@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2020 Oliver Hartkopp <socketcan@hartkopp.net>
+ */
+
+#ifndef _CAN_LENGTH_H
+#define _CAN_LENGTH_H
+
+/*
+ * can_cc_dlc2len(value) - convert a given data length code (dlc) of a
+ * Classical CAN frame into a valid data length of 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 can_cc_dlc2len(dlc)	(min_t(u8, (dlc), CAN_MAX_DLEN))
+
+/* 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);
+}
+
+/* get data length from raw data length code (DLC) */
+u8 can_fd_dlc2len(u8 dlc);
+
+/* map the sanitized data length to an appropriate data length code */
+u8 can_fd_len2dlc(u8 len);
+
+#endif /* !_CAN_LENGTH_H */