diff options
Diffstat (limited to 'drivers/net/can/ti_hecc.c')
| -rw-r--r-- | drivers/net/can/ti_hecc.c | 36 |
1 files changed, 31 insertions, 5 deletions
diff --git a/drivers/net/can/ti_hecc.c b/drivers/net/can/ti_hecc.c index 6ea29126c60b..b12fd0bd489d 100644 --- a/drivers/net/can/ti_hecc.c +++ b/drivers/net/can/ti_hecc.c @@ -73,6 +73,7 @@ MODULE_VERSION(HECC_MODULE_VERSION); */ #define HECC_MAX_RX_MBOX (HECC_MAX_MAILBOXES - HECC_MAX_TX_MBOX) #define HECC_RX_FIRST_MBOX (HECC_MAX_MAILBOXES - 1) +#define HECC_RX_LAST_MBOX (HECC_MAX_TX_MBOX) /* TI HECC module registers */ #define HECC_CANME 0x0 /* Mailbox enable */ @@ -82,7 +83,7 @@ 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 +386,15 @@ 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. + */ + mbx_mask = ~BIT(HECC_RX_LAST_MBOX); + 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 +539,7 @@ 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 ret = 1; mbx_mask = BIT(mbxno); data = hecc_read_mbx(priv, mbxno, HECC_CANMID); @@ -552,9 +561,26 @@ static unsigned int ti_hecc_mailbox_read(struct can_rx_offload *offload, } *timestamp = hecc_read_stamp(priv, mbxno); + + /* Check for FIFO overrun. + * + * All but the last RX mailbox have activated overwrite + * protection. So skip check for overrun, if we're not + * handling the last RX mailbox. + * + * As the overwrite protection for the last RX mailbox is + * disabled, the CAN core might update while we're reading + * it. This means the skb might be inconsistent. + * + * Return an error to let rx-offload discard this CAN frame. + */ + if (unlikely(mbxno == HECC_RX_LAST_MBOX && + hecc_read(priv, HECC_CANRML) & mbx_mask)) + ret = -ENOBUFS; + hecc_write(priv, HECC_CANRMP, mbx_mask); - return 1; + return ret; } static int ti_hecc_error(struct net_device *ndev, int int_status, @@ -884,7 +910,7 @@ static int ti_hecc_probe(struct platform_device *pdev) priv->offload.mailbox_read = ti_hecc_mailbox_read; priv->offload.mb_first = HECC_RX_FIRST_MBOX; - priv->offload.mb_last = HECC_MAX_TX_MBOX; + priv->offload.mb_last = HECC_RX_LAST_MBOX; err = can_rx_offload_add_timestamp(ndev, &priv->offload); if (err) { dev_err(&pdev->dev, "can_rx_offload_add_timestamp() failed\n"); |