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

Message ID 20240731-rockchip-canfd-v2-13-d9604c5b4be8@pengutronix.de (mailing list archive)
State Awaiting Upstream
Delegated to: Netdev Maintainers
Headers show
Series an: rockchip_canfd: add support for CAN-FD IP core found on Rockchip RK3568 | expand

Checks

Context Check Description
netdev/series_format fail Series longer than 15 patches
netdev/tree_selection success Guessed tree name to be net-next, async
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 42 this patch: 42
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 11 of 11 maintainers
netdev/build_clang success Errors and warnings before: 43 this patch: 43
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 43 this patch: 43
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 14 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Marc Kleine-Budde July 31, 2024, 9:37 a.m. UTC
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@rock-chips.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 drivers/net/can/rockchip/rockchip_canfd-tx.c | 7 +++++++
 1 file changed, 7 insertions(+)
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Patch

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)