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>
---
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 35c82289f2a3..4206ad5cb666 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,
--
2.17.1
