can: c_can: Fix startup logic

c_can_start() enables interrupts way too early. The first enabling
happens when setting the control mode in c_can_chip_config() and then
again at the end of the function.

But that happens before napi_enable() and that means that an interrupt
which comes in will disable interrupts again and call napi_schedule,
which ignores the request and the later napi_enable() is not making
thinks work either. So the interface is up with all device interrupts
disabled.

Move the device interrupt after napi_enable() and add it to the other
callsites of c_can_start() in c_can_set_mode() and c_can_power_up()

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

1 files changed, 17 insertions, 18 deletions

diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c
index a5c8dcfa8357..b1629a47c03b 100644
--- a/drivers/net/can/c_can/c_can.c
+++ b/drivers/net/can/c_can/c_can.c
@@ -612,30 +612,22 @@ static int c_can_chip_config(struct net_device *dev)
         struct c_can_priv *priv = netdev_priv(dev);
 
         /* enable automatic retransmission */
-        priv->write_reg(priv, C_CAN_CTRL_REG,
-                        CONTROL_ENABLE_AR);
+        priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_ENABLE_AR);
 
         if ((priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY) &&
             (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK)) {
                 /* loopback + silent mode : useful for hot self-test */
-                priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_EIE |
-                                CONTROL_SIE | CONTROL_IE | CONTROL_TEST);
-                priv->write_reg(priv, C_CAN_TEST_REG,
-                                TEST_LBACK | TEST_SILENT);
+                priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_TEST);
+                priv->write_reg(priv, C_CAN_TEST_REG, TEST_LBACK | TEST_SILENT);
         } else if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK) {
                 /* loopback mode : useful for self-test function */
-                priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_EIE |
-                                CONTROL_SIE | CONTROL_IE | CONTROL_TEST);
+                priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_TEST);
                 priv->write_reg(priv, C_CAN_TEST_REG, TEST_LBACK);
         } else if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY) {
                 /* silent mode : bus-monitoring mode */
-                priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_EIE |
-                                CONTROL_SIE | CONTROL_IE | CONTROL_TEST);
+                priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_TEST);
                 priv->write_reg(priv, C_CAN_TEST_REG, TEST_SILENT);
-        } else
-                /* normal mode*/
-                priv->write_reg(priv, C_CAN_CTRL_REG,
-                                CONTROL_EIE | CONTROL_SIE | CONTROL_IE);
+        }
 
         /* configure message objects */
         c_can_configure_msg_objects(dev);
@@ -662,9 +654,6 @@ static int c_can_start(struct net_device *dev)
         /* reset tx helper pointers */
         priv->tx_next = priv->tx_echo = 0;
 
-        /* enable status change, error and module interrupts */
-        c_can_enable_all_interrupts(priv, ENABLE_ALL_INTERRUPTS);
-
         return 0;
 }
 
@@ -681,6 +670,7 @@ static void c_can_stop(struct net_device *dev)
 
 static int c_can_set_mode(struct net_device *dev, enum can_mode mode)
 {
+        struct c_can_priv *priv = netdev_priv(dev);
         int err;
 
         switch (mode) {
@@ -689,6 +679,8 @@ static int c_can_set_mode(struct net_device *dev, enum can_mode mode)
                 if (err)
                         return err;
                 netif_wake_queue(dev);
+                /* enable status change, error and module interrupts */
+                c_can_enable_all_interrupts(priv, ENABLE_ALL_INTERRUPTS);
                 break;
         default:
                 return -EOPNOTSUPP;
@@ -1184,6 +1176,8 @@ static int c_can_open(struct net_device *dev)
         can_led_event(dev, CAN_LED_EVENT_OPEN);
 
         napi_enable(&priv->napi);
+        /* enable status change, error and module interrupts */
+        c_can_enable_all_interrupts(priv, ENABLE_ALL_INTERRUPTS);
         netif_start_queue(dev);
 
         return 0;
@@ -1281,6 +1275,7 @@ int c_can_power_up(struct net_device *dev)
         u32 val;
         unsigned long time_out;
         struct c_can_priv *priv = netdev_priv(dev);
+        int ret;
 
         if (!(dev->flags & IFF_UP))
                 return 0;
@@ -1307,7 +1302,11 @@ int c_can_power_up(struct net_device *dev)
         if (time_after(jiffies, time_out))
                 return -ETIMEDOUT;
 
-        return c_can_start(dev);
+        ret = c_can_start(dev);
+        if (!ret)
+                c_can_enable_all_interrupts(priv, ENABLE_ALL_INTERRUPTS);
+
+        return ret;
 }
 EXPORT_SYMBOL_GPL(c_can_power_up);
 #endif