can: c_can: Remove tx locking

Mark suggested to use one IF for the softirq and the other for the
xmit function to avoid the xmit lock.

That requires to write the frame into the interface first, then handle
the echo skb and store the dlc before committing the TX request to the
message ram.

We use an atomic to handle the active buffers instead of reading the
MSGVAL register as thats way faster especially on PCH/x86.

Suggested-by: Mark <mark5@del-llc.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

1 files changed, 1 insertions, 7 deletions

diff --git a/drivers/net/can/c_can/c_can.h b/drivers/net/can/c_can/c_can.h
index d9f59cc4fcb5..a5f10a01e49f 100644
--- a/drivers/net/can/c_can/c_can.h
+++ b/drivers/net/can/c_can/c_can.h
@@ -37,8 +37,6 @@
 
 #define C_CAN_MSG_OBJ_RX_SPLIT	9
 #define C_CAN_MSG_RX_LOW_LAST	(C_CAN_MSG_OBJ_RX_SPLIT - 1)
-
-#define C_CAN_NEXT_MSG_OBJ_MASK	(C_CAN_MSG_OBJ_TX_NUM - 1)
 #define RECEIVE_OBJECT_BITS	0x0000ffff
 
 enum reg {
@@ -175,16 +173,12 @@ struct c_can_priv {
 	struct napi_struct napi;
 	struct net_device *dev;
 	struct device *device;
-	spinlock_t xmit_lock;
-	int tx_object;
+	atomic_t tx_active;
 	int last_status;
 	u16 (*read_reg) (struct c_can_priv *priv, enum reg index);
 	void (*write_reg) (struct c_can_priv *priv, enum reg index, u16 val);
 	void __iomem *base;
 	const u16 *regs;
-	unsigned long irq_flags; /* for request_irq() */
-	unsigned int tx_next;
-	unsigned int tx_echo;
 	void *priv;		/* for board-specific data */
 	enum c_can_dev_id type;
 	u32 __iomem *raminit_ctrlreg;