diff options
| -rw-r--r-- | drivers/net/can/rockchip/rockchip_canfd-rx.c | 14 | ||||
| -rw-r--r-- | drivers/net/can/rockchip/rockchip_canfd.h | 22 |
2 files changed, 36 insertions, 0 deletions
diff --git a/drivers/net/can/rockchip/rockchip_canfd-rx.c b/drivers/net/can/rockchip/rockchip_canfd-rx.c index 5398aff0d180..609282359bca 100644 --- a/drivers/net/can/rockchip/rockchip_canfd-rx.c +++ b/drivers/net/can/rockchip/rockchip_canfd-rx.c @@ -47,6 +47,16 @@ rkcanfd_fifo_header_to_cfd_header(const struct rkcanfd_priv *priv, return len + cfd->len; } +static inline bool +rkcanfd_fifo_header_empty(const struct rkcanfd_fifo_header *header) +{ + /* Erratum 5: If the FIFO is empty, we read the same value for + * all elements. + */ + return header->frameinfo == header->id && + header->frameinfo == header->ts; +} + static int rkcanfd_handle_rx_int_one(struct rkcanfd_priv *priv) { struct net_device_stats *stats = &priv->ndev->stats; @@ -63,6 +73,10 @@ static int rkcanfd_handle_rx_int_one(struct rkcanfd_priv *priv) rkcanfd_read_rep(priv, RKCANFD_REG_RX_FIFO_RDATA, cfd->data, sizeof(cfd->data)); + /* Erratum 5: Counters for TXEFIFO and RXFIFO may be wrong */ + if (rkcanfd_fifo_header_empty(header)) + return 0; + len = rkcanfd_fifo_header_to_cfd_header(priv, header, cfd); /* Drop any received CAN-FD frames if CAN-FD mode is not diff --git a/drivers/net/can/rockchip/rockchip_canfd.h b/drivers/net/can/rockchip/rockchip_canfd.h index 3dafb5e68dc5..c775e75a2740 100644 --- a/drivers/net/can/rockchip/rockchip_canfd.h +++ b/drivers/net/can/rockchip/rockchip_canfd.h @@ -315,6 +315,28 @@ /* Erratum 5: Counters related to the TXFIFO and RXFIFO exhibit * abnormal counting behavior. + * + * The rk3568 CAN-FD errata sheet as of Tue 07 Nov 2023 11:25:31 +08:00 + * states that only the rk3568v2 is affected by this erratum, but + * tests with the rk3568v2 and rk3568v3 show that the RX_FIFO_CNT is + * sometimes too high. This leads to CAN frames being read from the + * FIFO, which is then already empty. + * + * Further tests on the rk3568v2 and rk3568v3 show that in this + * situation (i.e. empty FIFO) all elements of the FIFO header + * (frameinfo, id, ts) contain the same data. + * + * On the rk3568v2 and rk3568v3, this problem only occurs extremely + * rarely with the standard clock of 300 MHz, but almost immediately + * at 80 MHz. + * + * To workaround this problem, check for empty FIFO with + * rkcanfd_fifo_header_empty() in rkcanfd_handle_rx_int_one() and exit + * early. + * + * To reproduce: + * assigned-clocks = <&cru CLK_CANx>; + * assigned-clock-rates = <80000000>; */ #define RKCANFD_QUIRK_RK3568_ERRATUM_5 BIT(4) |