[PATCH can-next v2 13/20] can: rockchip_canfd: implement workaround for erratum 12

From: Marc Kleine-Budde
Date: Wed Jul 31 2024 - 05:41:53 EST


The rk3568 CAN-FD errata sheet as of Tue 07 Nov 2023 11:25:31 +08:00
says:

| A dominant bit at the third bit of the intermission may cause a
| transmission error.
|
| When sampling the third bit of the intermission as a dominant bit, if
| tx_req is configured to transmit extended frames at this time, the
| extended frame may be sent to the bus in the format of a standard
| frame. The extended frame will be sent as a standard frame and will not
| result in error frames

Turn on "Interframe Spaceing RX Mode" only during TX to work around
erratum 12, according to rock-chip:

| Spaceing RX Mode = 1, the third Bit between frames cannot receive
| and send, and the fourth Bit begins to receive and send.
|
| Spaceing RX Mode = 0, allowing the third Bit between frames to
| receive and send.

Message-ID: <be72939f-0a9e-0608-dfff-7b0096a26eba@xxxxxxxxxxxxxx>
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
---
drivers/net/can/rockchip/rockchip_canfd-tx.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/drivers/net/can/rockchip/rockchip_canfd-tx.c b/drivers/net/can/rockchip/rockchip_canfd-tx.c
index e98e7a836b83..9db6d90a4e7f 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-tx.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-tx.c
@@ -11,7 +11,14 @@
static void rkcanfd_start_xmit_write_cmd(const struct rkcanfd_priv *priv,
const u32 reg_cmd)
{
+ if (priv->devtype_data.quirks & RKCANFD_QUIRK_RK3568_ERRATUM_12)
+ rkcanfd_write(priv, RKCANFD_REG_MODE, priv->reg_mode_default |
+ RKCANFD_REG_MODE_SPACE_RX_MODE);
+
rkcanfd_write(priv, RKCANFD_REG_CMD, reg_cmd);
+
+ if (priv->devtype_data.quirks & RKCANFD_QUIRK_RK3568_ERRATUM_12)
+ rkcanfd_write(priv, RKCANFD_REG_MODE, priv->reg_mode_default);
}

void rkcanfd_xmit_retry(struct rkcanfd_priv *priv)

--
2.43.0