From: Kurt Van Dijck <dev.kurt@xxxxxxxxxxxxxxxxxxxxxx>
When the status register is read without status IRQ pending, it may get
into a state that it goes into busoff state without having its irq
activated, so the driver wil never know.
Thanks to Wolfgang and Joe for bringing up the first idea.
Signed-off-by: Kurt Van Dijck <dev.kurt@xxxxxxxxxxxxxxxxxxxxxx>
Cc: Wolfgang Grandegger <wg@xxxxxxxxxxxxxx>
Cc: Joe Burmeister <joe.burmeister@xxxxxxxxxxxxx>
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
---
Hello,
as mentioned in another mail, I'll take this patch for the can branch to
fix this problem before switching to rx-offload.
Marc
changes since v1:
- c_can_isr(): rename intreg -> reg_into to match name scheme in driver.
drivers/net/can/c_can/c_can.c | 25 ++++++++++++++++++++-----
drivers/net/can/c_can/c_can.h | 1 +
2 files changed, 21 insertions(+), 5 deletions(-)
diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c
index e1e9b87dd4d2..8e9f5620c9a2 100644
--- a/drivers/net/can/c_can/c_can.c
+++ b/drivers/net/can/c_can/c_can.c
@@ -98,6 +98,9 @@
#define BTR_TSEG2_SHIFT 12
#define BTR_TSEG2_MASK (0x7 << BTR_TSEG2_SHIFT)
+/* interrupt register */
+#define INT_STS_PENDING 0x8000
+
/* brp extension register */
#define BRP_EXT_BRPE_MASK 0x0f
#define BRP_EXT_BRPE_SHIFT 0
@@ -1065,10 +1068,16 @@ static int c_can_poll(struct napi_struct *napi, int quota)
u16 curr, last = priv->last_status;
int work_done = 0;
- priv->last_status = curr = priv->read_reg(priv, C_CAN_STS_REG);
- /* Ack status on C_CAN. D_CAN is self clearing */
- if (priv->type != BOSCH_D_CAN)
- priv->write_reg(priv, C_CAN_STS_REG, LEC_UNUSED);
+ /* Only read the status register if a status interrupt was pending */
+ if (atomic_xchg(&priv->sie_pending, 0)) {
+ priv->last_status = curr = priv->read_reg(priv, C_CAN_STS_REG);
+ /* Ack status on C_CAN. D_CAN is self clearing */
+ if (priv->type != BOSCH_D_CAN)
+ priv->write_reg(priv, C_CAN_STS_REG, LEC_UNUSED);
+ } else {
+ /* no change detected ... */
+ curr = last;
+ }
/* handle state changes */
if ((curr & STATUS_EWARN) && (!(last & STATUS_EWARN))) {
@@ -1125,10 +1134,16 @@ static irqreturn_t c_can_isr(int irq, void *dev_id)
{
struct net_device *dev = (struct net_device *)dev_id;
struct c_can_priv *priv = netdev_priv(dev);
+ int reg_int;
- if (!priv->read_reg(priv, C_CAN_INT_REG))
+ reg_int = priv->read_reg(priv, C_CAN_INT_REG);
+ if (!reg_int)
return IRQ_NONE;
+ /* save for later use */
+ if (reg_int & INT_STS_PENDING)
+ atomic_set(&priv->sie_pending, 1);
+
/* disable all interrupts and schedule the NAPI */
c_can_irq_control(priv, false);
napi_schedule(&priv->napi);
diff --git a/drivers/net/can/c_can/c_can.h b/drivers/net/can/c_can/c_can.h
index 8acdc7fa4792..d5567a7c1c6d 100644
--- a/drivers/net/can/c_can/c_can.h
+++ b/drivers/net/can/c_can/c_can.h
@@ -198,6 +198,7 @@ struct c_can_priv {
struct net_device *dev;
struct device *device;
atomic_t tx_active;
+ atomic_t sie_pending;
unsigned long tx_dir;
int last_status;
u16 (*read_reg) (const struct c_can_priv *priv, enum reg index);
--
2.23.0
