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Subject[PATCH] can: m_can: support transmit frame in CAN FD format
Date
Add support to transmit the frame in the CAN FD format and with
the bit rate switching.

Tested on SAMA5D2 Xplained board.

Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
---
The testing is based on
[RESEND PATCH 1/1] can: m_can: fix bitrate setup on latest silicon
http://lkml.iu.edu/hypermail/linux/kernel/1702.1/05347.html

drivers/net/can/m_can/m_can.c | 21 +++++++++++++++++----
1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 195f15edb32e..9ef9b337d25b 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -266,8 +266,12 @@ enum m_can_mram_cfg {

/* Tx Buffer Element */
/* R0 */
+#define TX_BUF_ESI BIT(31)
#define TX_BUF_XTD BIT(30)
#define TX_BUF_RTR BIT(29)
+#define TX_BUF_EFC BIT(23)
+#define TX_BUF_EDL BIT(21)
+#define TX_BUF_BRS BIT(20)

/* address offset and element number for each FIFO/Buffer in the Message RAM */
struct mram_cfg {
@@ -884,7 +888,7 @@ static void m_can_chip_config(struct net_device *dev)
}

if (priv->can.ctrlmode & CAN_CTRLMODE_FD)
- cccr |= CCCR_CME_CANFD_BRS << CCCR_CME_SHIFT;
+ cccr |= (CCCR_CME_CANFD_BRS | CCCR_CME_CANFD) << CCCR_CME_SHIFT;

m_can_write(priv, M_CAN_CCCR, cccr);
m_can_write(priv, M_CAN_TEST, test);
@@ -1047,6 +1051,7 @@ static netdev_tx_t m_can_start_xmit(struct sk_buff *skb,
struct canfd_frame *cf = (struct canfd_frame *)skb->data;
u32 id, cccr;
int i;
+ u32 dlc;

if (can_dropped_invalid_skb(dev, skb))
return NETDEV_TX_OK;
@@ -1065,7 +1070,6 @@ static netdev_tx_t m_can_start_xmit(struct sk_buff *skb,

/* message ram configuration */
m_can_fifo_write(priv, 0, M_CAN_FIFO_ID, id);
- m_can_fifo_write(priv, 0, M_CAN_FIFO_DLC, can_len2dlc(cf->len) << 16);

for (i = 0; i < cf->len; i += 4)
m_can_fifo_write(priv, 0, M_CAN_FIFO_DATA(i / 4),
@@ -1073,20 +1077,29 @@ static netdev_tx_t m_can_start_xmit(struct sk_buff *skb,

can_put_echo_skb(skb, dev, 0);

+ dlc = can_len2dlc(cf->len) << 16;
+
if (priv->can.ctrlmode & CAN_CTRLMODE_FD) {
cccr = m_can_read(priv, M_CAN_CCCR);
cccr &= ~(CCCR_CMR_MASK << CCCR_CMR_SHIFT);
if (can_is_canfd_skb(skb)) {
- if (cf->flags & CANFD_BRS)
+ dlc |= TX_BUF_EDL;
+ if (cf->flags & CANFD_ESI)
+ dlc |= TX_BUF_ESI;
+ if (cf->flags & CANFD_BRS) {
+ dlc |= TX_BUF_BRS;
cccr |= CCCR_CMR_CANFD_BRS << CCCR_CMR_SHIFT;
- else
+ } else {
cccr |= CCCR_CMR_CANFD << CCCR_CMR_SHIFT;
+ }
} else {
cccr |= CCCR_CMR_CAN << CCCR_CMR_SHIFT;
}
m_can_write(priv, M_CAN_CCCR, cccr);
}

+ m_can_fifo_write(priv, 0, M_CAN_FIFO_DLC, dlc);
+
/* enable first TX buffer to start transfer */
m_can_write(priv, M_CAN_TXBTIE, 0x1);
m_can_write(priv, M_CAN_TXBAR, 0x1);
--
2.11.0
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