[PATCH can-next v2 14/20] can: rockchip_canfd: rkcanfd_get_berr_counter_corrected(): work around broken {RX,TX}ERRORCNT register
From: Marc Kleine-Budde
Date: Wed Jul 31 2024 - 05:41:30 EST
Tests show that sometimes both CAN bus error counters read 0x0, even
if the controller is in warning mode
(RKCANFD_REG_STATE_ERROR_WARNING_STATE in RKCANFD_REG_STATE
set).
To work around this issue, if both error counters read from hardware
are 0x0, use the structure priv->bec, otherwise save the read value in
priv->bec.
In rkcanfd_handle_rx_int_one() decrement the priv->bec.rxerr for
successfully RX'ed CAN frames.
In rkcanfd_handle_tx_done_one() decrement the priv->bec.txerr for
successfully TX'ed CAN frames.
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
---
drivers/net/can/rockchip/rockchip_canfd-core.c | 50 ++++++++++++++++++++++----
drivers/net/can/rockchip/rockchip_canfd-rx.c | 15 ++++++++
drivers/net/can/rockchip/rockchip_canfd-tx.c | 8 +++++
drivers/net/can/rockchip/rockchip_canfd.h | 2 ++
4 files changed, 69 insertions(+), 6 deletions(-)
diff --git a/drivers/net/can/rockchip/rockchip_canfd-core.c b/drivers/net/can/rockchip/rockchip_canfd-core.c
index 237b81c71dd8..5d78ec8dba7e 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-core.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-core.c
@@ -159,11 +159,47 @@ static int rkcanfd_set_bittiming(struct rkcanfd_priv *priv)
return 0;
}
-static void rkcanfd_get_berr_counter_raw(struct rkcanfd_priv *priv,
- struct can_berr_counter *bec)
+static void rkcanfd_get_berr_counter_corrected(struct rkcanfd_priv *priv,
+ struct can_berr_counter *bec)
{
+ struct can_berr_counter bec_raw;
+ u32 reg_state;
+
bec->rxerr = rkcanfd_read(priv, RKCANFD_REG_RXERRORCNT);
bec->txerr = rkcanfd_read(priv, RKCANFD_REG_TXERRORCNT);
+ bec_raw = *bec;
+
+ /* Tests show that sometimes both CAN bus error counters read
+ * 0x0, even if the controller is in warning mode
+ * (RKCANFD_REG_STATE_ERROR_WARNING_STATE in RKCANFD_REG_STATE
+ * set).
+ *
+ * In case both error counters read 0x0, use the struct
+ * priv->bec, otherwise save the read value to priv->bec.
+ *
+ * rkcanfd_handle_rx_int_one() handles the decrementing of
+ * priv->bec.rxerr for successfully RX'ed CAN frames.
+ *
+ * Luckily the controller doesn't decrement the RX CAN bus
+ * error counter in hardware for self received TX'ed CAN
+ * frames (RKCANFD_REG_MODE_RXSTX_MODE), so RXSTX doesn't
+ * interfere with proper RX CAN bus error counters.
+ *
+ * rkcanfd_handle_tx_done_one() handles the decrementing of
+ * priv->bec.txerr for successfully TX'ed CAN frames.
+ */
+ if (!bec->rxerr && !bec->txerr)
+ *bec = priv->bec;
+ else
+ priv->bec = *bec;
+
+ reg_state = rkcanfd_read(priv, RKCANFD_REG_STATE);
+ netdev_vdbg(priv->ndev,
+ "%s: Raw/Cor: txerr=%3u/%3u rxerr=%3u/%3u Bus Off=%u Warning=%u\n",
+ __func__,
+ bec_raw.txerr, bec->txerr, bec_raw.rxerr, bec->rxerr,
+ !!(reg_state & RKCANFD_REG_STATE_BUS_OFF_STATE),
+ !!(reg_state & RKCANFD_REG_STATE_ERROR_WARNING_STATE));
}
static int rkcanfd_get_berr_counter(const struct net_device *ndev,
@@ -176,7 +212,7 @@ static int rkcanfd_get_berr_counter(const struct net_device *ndev,
if (err)
return err;
- rkcanfd_get_berr_counter_raw(priv, bec);
+ rkcanfd_get_berr_counter_corrected(priv, bec);
pm_runtime_put(ndev->dev.parent);
@@ -252,6 +288,8 @@ static void rkcanfd_chip_start(struct rkcanfd_priv *priv)
RKCANFD_REG_INT_OVERLOAD_INT |
RKCANFD_REG_INT_TX_FINISH_INT;
+ memset(&priv->bec, 0x0, sizeof(priv->bec));
+
rkcanfd_chip_fifo_setup(priv);
rkcanfd_timestamp_init(priv);
rkcanfd_set_bittiming(priv);
@@ -488,7 +526,7 @@ static int rkcanfd_handle_error_int(struct rkcanfd_priv *priv)
if (cf) {
struct can_berr_counter bec;
- rkcanfd_get_berr_counter_raw(priv, &bec);
+ rkcanfd_get_berr_counter_corrected(priv, &bec);
cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR | CAN_ERR_CNT;
cf->data[6] = bec.txerr;
cf->data[7] = bec.rxerr;
@@ -517,7 +555,7 @@ static int rkcanfd_handle_state_error_int(struct rkcanfd_priv *priv)
u32 timestamp;
int err;
- rkcanfd_get_berr_counter_raw(priv, &bec);
+ rkcanfd_get_berr_counter_corrected(priv, &bec);
can_state_get_by_berr_counter(ndev, &bec, &tx_state, &rx_state);
new_state = max(tx_state, rx_state);
@@ -570,7 +608,7 @@ rkcanfd_handle_rx_fifo_overflow_int(struct rkcanfd_priv *priv)
if (skb)
return 0;
- rkcanfd_get_berr_counter_raw(priv, &bec);
+ rkcanfd_get_berr_counter_corrected(priv, &bec);
cf->can_id |= CAN_ERR_CRTL | CAN_ERR_CNT;
cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
diff --git a/drivers/net/can/rockchip/rockchip_canfd-rx.c b/drivers/net/can/rockchip/rockchip_canfd-rx.c
index 31cee3362f1e..eff08948840c 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-rx.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-rx.c
@@ -167,6 +167,13 @@ static int rkcanfd_rxstx_filter(struct rkcanfd_priv *priv,
/* Affected by Erratum 6 */
+ /* Manual handling of CAN Bus Error counters. See
+ * rkcanfd_get_corrected_berr_counter() for detailed
+ * explanation.
+ */
+ if (priv->bec.txerr)
+ priv->bec.txerr--;
+
*tx_done = true;
stats->tx_packets++;
@@ -229,6 +236,14 @@ static int rkcanfd_handle_rx_int_one(struct rkcanfd_priv *priv)
return 0;
}
+ /* Manual handling of CAN Bus Error counters. See
+ * rkcanfd_get_corrected_berr_counter() for detailed
+ * explanation.
+ */
+ if (priv->bec.rxerr)
+ priv->bec.rxerr = min(CAN_ERROR_PASSIVE_THRESHOLD,
+ priv->bec.rxerr) - 1;
+
if (header->frameinfo & RKCANFD_REG_FD_FRAMEINFO_FDF)
skb = alloc_canfd_skb(priv->ndev, &skb_cfd);
else
diff --git a/drivers/net/can/rockchip/rockchip_canfd-tx.c b/drivers/net/can/rockchip/rockchip_canfd-tx.c
index 9db6d90a4e7f..f8e74e814b3b 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-tx.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-tx.c
@@ -113,6 +113,14 @@ void rkcanfd_handle_tx_done_one(struct rkcanfd_priv *priv, const u32 ts,
unsigned int tx_tail;
tx_tail = rkcanfd_get_tx_tail(priv);
+
+ /* Manual handling of CAN Bus Error counters. See
+ * rkcanfd_get_corrected_berr_counter() for detailed
+ * explanation.
+ */
+ if (priv->bec.txerr)
+ priv->bec.txerr--;
+
stats->tx_bytes +=
can_rx_offload_get_echo_skb_queue_timestamp(&priv->offload,
tx_tail, ts,
diff --git a/drivers/net/can/rockchip/rockchip_canfd.h b/drivers/net/can/rockchip/rockchip_canfd.h
index 3fe6ddcdd8ac..67f135fbcfb9 100644
--- a/drivers/net/can/rockchip/rockchip_canfd.h
+++ b/drivers/net/can/rockchip/rockchip_canfd.h
@@ -459,6 +459,8 @@ struct rkcanfd_priv {
u32 reg_int_mask_default;
struct rkcanfd_devtype_data devtype_data;
+ struct can_berr_counter bec;
+
struct reset_control *reset;
struct clk_bulk_data *clks;
int clks_num;
--
2.43.0