diff mbox series

[net-next,12/20] can: rockchip_canfd: implement workaround for erratum 6

Message ID 20240904094218.1925386-13-mkl@pengutronix.de (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series [net-next,01/20] dt-bindings: can: rockchip_canfd: add rockchip CAN-FD controller | expand

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Context Check Description
netdev/series_format warning Pull request is its own cover letter; Series longer than 15 patches (PR)
netdev/tree_selection success Clearly marked for 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: 16 this patch: 16
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers warning 5 maintainers not CCed: pabeni@redhat.com mailhol.vincent@wanadoo.fr edumazet@google.com linux-arm-kernel@lists.infradead.org linux-rockchip@lists.infradead.org
netdev/build_clang success Errors and warnings before: 16 this patch: 16
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: 16 this patch: 16
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 101 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 Sept. 4, 2024, 9:38 a.m. UTC
The rk3568 CAN-FD errata sheet as of Tue 07 Nov 2023 11:25:31 +08:00
says:

| The CAN controller's transmission of extended frames may
| intermittently change into standard frames.
|
| When using the CAN controller to send extended frames, if the
| 'tx_req' is configured as 1 and coincides with the internal
| transmission point, the extended frame will be transmitted onto the
| bus in the format of a standard frame.

To work around Erratum 6, the driver is in self-receiving mode (RXSTX)
and all received CAN frames are passed through rkcanfd_rxstx_filter().

Add a check in rkcanfd_rxstx_filter() whether the received frame
corresponds to the current outgoing frame, but the extended CAN ID has
been mangled to a standard ID. In this case re-send the original CAN
frame.

Tested-by: Alibek Omarov <a1ba.omarov@gmail.com>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patch.msgid.link/20240904-rockchip-canfd-v5-12-8ae22bcb27cc@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 drivers/net/can/rockchip/rockchip_canfd-rx.c | 44 ++++++++++++++++++++
 drivers/net/can/rockchip/rockchip_canfd-tx.c |  8 ++++
 drivers/net/can/rockchip/rockchip_canfd.h    | 19 +++++++++
 3 files changed, 71 insertions(+)
diff mbox series

Patch

diff --git a/drivers/net/can/rockchip/rockchip_canfd-rx.c b/drivers/net/can/rockchip/rockchip_canfd-rx.c
index 650dfd41e0a0..31cee3362f1e 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-rx.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-rx.c
@@ -95,6 +95,7 @@  static int rkcanfd_rxstx_filter(struct rkcanfd_priv *priv,
 				const struct canfd_frame *cfd_rx, const u32 ts,
 				bool *tx_done)
 {
+	struct net_device_stats *stats = &priv->ndev->stats;
 	const struct canfd_frame *cfd_nominal;
 	const struct sk_buff *skb;
 	unsigned int tx_tail;
@@ -130,6 +131,49 @@  static int rkcanfd_rxstx_filter(struct rkcanfd_priv *priv,
 		return 0;
 	}
 
+	if (!(priv->devtype_data.quirks & RKCANFD_QUIRK_RK3568_ERRATUM_6))
+		return 0;
+
+	/* Erratum 6: Extended frames may be send as standard frames.
+	 *
+	 * Not affected if:
+	 * - TX'ed a standard frame -or-
+	 * - RX'ed an extended frame
+	 */
+	if (!(cfd_nominal->can_id & CAN_EFF_FLAG) ||
+	    (cfd_rx->can_id & CAN_EFF_FLAG))
+		return 0;
+
+	/* Not affected if:
+	 * - standard part and RTR flag of the TX'ed frame
+	 *   is not equal the CAN-ID and RTR flag of the RX'ed frame.
+	 */
+	if ((cfd_nominal->can_id & (CAN_RTR_FLAG | CAN_SFF_MASK)) !=
+	    (cfd_rx->can_id & (CAN_RTR_FLAG | CAN_SFF_MASK)))
+		return 0;
+
+	/* Not affected if:
+	 * - length is not the same
+	 */
+	if (cfd_nominal->len != cfd_rx->len)
+		return 0;
+
+	/* Not affected if:
+	 * - the data of non RTR frames is different
+	 */
+	if (!(cfd_nominal->can_id & CAN_RTR_FLAG) &&
+	    memcmp(cfd_nominal->data, cfd_rx->data, cfd_nominal->len))
+		return 0;
+
+	/* Affected by Erratum 6 */
+
+	*tx_done = true;
+
+	stats->tx_packets++;
+	stats->tx_errors++;
+
+	rkcanfd_xmit_retry(priv);
+
 	return 0;
 }
 
diff --git a/drivers/net/can/rockchip/rockchip_canfd-tx.c b/drivers/net/can/rockchip/rockchip_canfd-tx.c
index 668a902f4c2a..e98e7a836b83 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-tx.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-tx.c
@@ -14,6 +14,14 @@  static void rkcanfd_start_xmit_write_cmd(const struct rkcanfd_priv *priv,
 	rkcanfd_write(priv, RKCANFD_REG_CMD, reg_cmd);
 }
 
+void rkcanfd_xmit_retry(struct rkcanfd_priv *priv)
+{
+	const unsigned int tx_head = rkcanfd_get_tx_head(priv);
+	const u32 reg_cmd = RKCANFD_REG_CMD_TX_REQ(tx_head);
+
+	rkcanfd_start_xmit_write_cmd(priv, reg_cmd);
+}
+
 int rkcanfd_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 {
 	struct rkcanfd_priv *priv = netdev_priv(ndev);
diff --git a/drivers/net/can/rockchip/rockchip_canfd.h b/drivers/net/can/rockchip/rockchip_canfd.h
index a4688411e586..3fe6ddcdd8ac 100644
--- a/drivers/net/can/rockchip/rockchip_canfd.h
+++ b/drivers/net/can/rockchip/rockchip_canfd.h
@@ -342,6 +342,24 @@ 
 
 /* Erratum 6: The CAN controller's transmission of extended frames may
  * intermittently change into standard frames
+ *
+ * Work around this issue by activating self reception (RXSTX). If we
+ * have pending TX CAN frames, check all RX'ed CAN frames in
+ * rkcanfd_rxstx_filter().
+ *
+ * If it's a frame we've send and it's OK, call the TX complete
+ * handler: rkcanfd_handle_tx_done_one(). Mask the TX complete IRQ.
+ *
+ * If it's a frame we've send, but the CAN-ID is mangled, resend the
+ * original extended frame.
+ *
+ * To reproduce:
+ * host:
+ *   canfdtest -evx -g can0
+ *   candump any,0:80000000 -cexdtA
+ * dut:
+ *   canfdtest -evx can0
+ *   ethtool -S can0
  */
 #define RKCANFD_QUIRK_RK3568_ERRATUM_6 BIT(5)
 
@@ -499,6 +517,7 @@  int rkcanfd_handle_rx_int(struct rkcanfd_priv *priv);
 
 void rkcanfd_timestamp_init(struct rkcanfd_priv *priv);
 
+void rkcanfd_xmit_retry(struct rkcanfd_priv *priv);
 int rkcanfd_start_xmit(struct sk_buff *skb, struct net_device *ndev);
 void rkcanfd_handle_tx_done_one(struct rkcanfd_priv *priv, const u32 ts,
 				unsigned int *frame_len_p);