net/netdev: Change SIOCSCANBITRATE to require interface down.

Previously, SIOCSCANBITRATE brought the iterface up to ensure changes
where immediately applied. This was confusing, see
https://lists.apache.org/thread/g8d0m6yp7noywhroby5br4hxt3r4og2c
Now SIOCSCANBITRATE fails is interface is up.
All existing SocketCAN drivers updated.

Signed-off-by: Carlos Sanchez <carlossanchez@geotab.com>

Author: csanchezdll

arch/arm/src/imx9/imx9_flexcan.c

@@ -1601,15 +1601,13 @@ static int imx9_ioctl(struct net_driver_s *dev, int cmd,
 
           if (ret == OK)
             {
-              /* Reset CAN controller and start with new timings */
+              /* Apply the new timings (interface is guaranteed to be down) */
 
               priv->arbi_timing = arbi_timing;
               if (priv->canfd_capable)
               {
                 priv->data_timing = data_timing;
               }
-
-              imx9_ifup(dev);
             }
         }
         break;

arch/arm/src/imxrt/imxrt_flexcan.c

@@ -1569,15 +1569,13 @@ static int imxrt_ioctl(struct net_driver_s *dev, int cmd,
 
           if (ret == OK)
             {
-              /* Reset CAN controller and start with new timings */
+              /* Apply the new timings (interface is guaranteed to be down) */
 
               priv->arbi_timing = arbi_timing;
               if (priv->canfd_capable)
               {
                 priv->data_timing = data_timing;
               }
-
-              imxrt_ifup(dev);
             }
         }
         break;

arch/arm/src/kinetis/kinetis_flexcan.c

@@ -1533,13 +1533,12 @@ static int kinetis_ioctl(struct net_driver_s *dev, int cmd,
 
           if (ret == OK)
             {
-              /* Reset CAN controller and start with new timings */
+              /* Apply the new timings (interface is guaranteed to be down) */
 
               priv->arbi_timing = arbi_timing;
 #ifdef CONFIG_NET_CAN_CANFD
               priv->data_timing = data_timing;
 #endif
-              kinetis_ifup(dev);
             }
         }
         break;

arch/arm/src/s32k1xx/s32k1xx_flexcan.c

@@ -1516,13 +1516,12 @@ static int s32k1xx_ioctl(struct net_driver_s *dev, int cmd,
 
           if (ret == OK)
             {
-              /* Reset CAN controller and start with new timings */
+              /* Apply the new timings (interface is guaranteed to be down) */
 
               priv->arbi_timing = arbi_timing;
 #ifdef CONFIG_NET_CAN_CANFD
               priv->data_timing = data_timing;
 #endif
-              s32k1xx_ifup(dev);
             }
         }
         break;

arch/arm/src/s32k3xx/s32k3xx_flexcan.c

@@ -1707,13 +1707,12 @@ static int s32k3xx_ioctl(struct net_driver_s *dev, int cmd,
 
           if (ret == OK)
             {
-              /* Reset CAN controller and start with new timings */
+              /* Apply the new timings (interface is guaranteed to be down) */
 
               priv->arbi_timing = arbi_timing;
 #ifdef CONFIG_NET_CAN_CANFD
               priv->data_timing = data_timing;
 #endif
-              s32k3xx_ifup(dev);
             }
         }
         break;

arch/arm/src/stm32h7/stm32_fdcan_sock.c

@@ -1966,19 +1966,12 @@ static int fdcan_netdev_ioctl(struct net_driver_s *dev, int cmd,
           struct can_ioctl_data_s *req =
               (struct can_ioctl_data_s *)((uintptr_t)arg);
 
+          /* Apply the new timings (interface is guaranteed to be down) */
+
           priv->arbi_timing.bitrate = req->arbi_bitrate * 1000;
 #ifdef CONFIG_NET_CAN_CANFD
           priv->data_timing.bitrate = req->data_bitrate * 1000;
 #endif
-
-          /* Reset CAN controller and start with new timings */
-
-          ret = fdcan_initialize(priv);
-
-          if (ret == OK)
-            {
-              ret = fdcan_ifup(dev);
-            }
         }
         break;
 #endif /* CONFIG_NETDEV_CAN_BITRATE_IOCTL */

arch/arm64/src/imx9/imx9_flexcan.c

@@ -1634,15 +1634,13 @@ static int imx9_ioctl(struct net_driver_s *dev, int cmd,
 
           if (ret == OK)
             {
-              /* Reset CAN controller and start with new timings */
+              /* Apply the new timings (interface is guaranteed to be down) */
 
               priv->arbi_timing = arbi_timing;
               if (priv->canfd_capable)
               {
                 priv->data_timing = data_timing;
               }
-
-              imx9_ifup(dev);
             }
         }
         break;

net/netdev/netdev_ioctl.c

@@ -1176,8 +1176,18 @@ static int netdev_ifr_ioctl(FAR struct socket *psock, int cmd,
 #endif
 
 #if defined(CONFIG_NETDEV_IOCTL) && defined(CONFIG_NETDEV_CAN_BITRATE_IOCTL)
-      case SIOCGCANBITRATE:  /* Get bitrate from a CAN controller */
       case SIOCSCANBITRATE:  /* Set bitrate of a CAN controller */
+        if (dev->d_flags & IFF_UP)
+          {
+            /* Cannot set bitrate if the interface is up. */
+
+            ret = -EBUSY;
+            break;
+          }
+
+        /* If down, fall-through to common code in SIOCGCANBITRATE. */
+
+      case SIOCGCANBITRATE:  /* Get bitrate from a CAN controller */
         if (dev->d_ioctl)
           {
             FAR struct can_ioctl_data_s *can_bitrate_data =