From: Jeroen Hofstee <jhofstee@xxxxxxxxxxxxxxxxx> When the rx fifo overflows the ti_hecc would silently drop them since the overwrite protection is enabled for all mailboxes. So disable it for the lowest priority mailbox and increment the rx_fifo_errors when receive message lost is set. Drop the message itself in that case, since it might be partially updated. Signed-off-by: Jeroen Hofstee <jhofstee@xxxxxxxxxxxxxxxxx> Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> --- drivers/net/can/ti_hecc.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-) diff --git a/drivers/net/can/ti_hecc.c b/drivers/net/can/ti_hecc.c index 6ea29126c60b..c2d83ada203a 100644 --- a/drivers/net/can/ti_hecc.c +++ b/drivers/net/can/ti_hecc.c @@ -82,7 +82,7 @@ MODULE_VERSION(HECC_MODULE_VERSION); #define HECC_CANTA 0x10 /* Transmission acknowledge */ #define HECC_CANAA 0x14 /* Abort acknowledge */ #define HECC_CANRMP 0x18 /* Receive message pending */ -#define HECC_CANRML 0x1C /* Remote message lost */ +#define HECC_CANRML 0x1C /* Receive message lost */ #define HECC_CANRFP 0x20 /* Remote frame pending */ #define HECC_CANGAM 0x24 /* SECC only:Global acceptance mask */ #define HECC_CANMC 0x28 /* Master control */ @@ -385,8 +385,17 @@ static void ti_hecc_start(struct net_device *ndev) /* Enable tx interrupts */ hecc_set_bit(priv, HECC_CANMIM, BIT(HECC_MAX_TX_MBOX) - 1); - /* Prevent message over-write & Enable interrupts */ - hecc_write(priv, HECC_CANOPC, HECC_SET_REG); + /* Prevent message over-write to create a rx fifo, but not for + * the lowest priority mailbox, since that allows detecting + * overflows instead of the hardware silently dropping the + * messages. The lowest rx mailbox is one above the tx ones, + * hence its mbxno is the number of tx mailboxes. + */ + mbxno = HECC_MAX_TX_MBOX; + mbx_mask = ~BIT(mbxno); + hecc_write(priv, HECC_CANOPC, mbx_mask); + + /* Enable interrupts */ if (priv->use_hecc1int) { hecc_write(priv, HECC_CANMIL, HECC_SET_REG); hecc_write(priv, HECC_CANGIM, HECC_CANGIM_DEF_MASK | @@ -531,6 +540,7 @@ static unsigned int ti_hecc_mailbox_read(struct can_rx_offload *offload, { struct ti_hecc_priv *priv = rx_offload_to_priv(offload); u32 data, mbx_mask; + int lost; mbx_mask = BIT(mbxno); data = hecc_read_mbx(priv, mbxno, HECC_CANMID); @@ -552,9 +562,12 @@ static unsigned int ti_hecc_mailbox_read(struct can_rx_offload *offload, } *timestamp = hecc_read_stamp(priv, mbxno); + lost = hecc_read(priv, HECC_CANRML) & mbx_mask; + if (unlikely(lost)) + priv->offload.dev->stats.rx_fifo_errors++; hecc_write(priv, HECC_CANRMP, mbx_mask); - return 1; + return !lost; } static int ti_hecc_error(struct net_device *ndev, int int_status, -- 2.23.0