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Subject[PATCH v2] can: m_can: enable transmission of FD frame on latest version
Date
Enables the transmission of CAN FD frames on M_CAN IP core >= v3.1.x
and with the bit rate switching.

Tested on M_CAN IP 3.1.0 (CREL = 0x31040730) of SAMA5D2 SoC.

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

Changes in v2:
- Rename TX_BUF_EDL with TX_BUF_FDF.
- Improve the commit log to avoid misleading.

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 246584ed89b6..c2dd2550de40 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -283,8 +283,12 @@ 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_FDF BIT(21)
+#define TX_BUF_BRS BIT(20)

/* address offset and element number for each FIFO/Buffer in the Message RAM */
struct mram_cfg {
@@ -916,7 +920,7 @@ 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);
@@ -1079,6 +1083,7 @@ 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;
@@ -1097,7 +1102,6 @@ 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),
@@ -1105,20 +1109,29 @@ 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_FDF;
+ 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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