arch/arm/stm32h7: do not log the frames of packet sockets as unknown.

A frame that a packet socket consumes was given to pkt_input() and then
logged as "Dropped, Unknown type" because it is neither IP nor ARP. With
a PTP grandmaster on the network that is one warning for each frame, and
the log of RAM fills in seconds, so it hides the messages of the start of
the system.

Do not log the frames of the type of PTP or of IPv6 when packet sockets
are enabled, as the driver of the legacy STM32 does.

Signed-off-by: Daniel P. Carvalho <danieloak@gmail.com>
Assisted-by: Claude:claude-sonnet-5

arch/arm/src/stm32h7/stm32_ethernet.c

@@ -40,6 +40,7 @@
 
 #include <arch/barriers.h>
 #include <arpa/inet.h>
+#include <netinet/if_ether.h>
 
 #include <nuttx/arch.h>
 #include <nuttx/irq.h>
@@ -2392,7 +2393,18 @@ static void stm32_receive(struct stm32_ethmac_s *priv)
       else
 #endif
         {
-          nwarn("WARNING: DROPPED Unknown type: %04x\n", BUF->type);
+#ifdef CONFIG_NET_PKT
+          /* Frames that packet sockets consume (PTP over Ethernet and
+           * IPv6) were already given to pkt_input() above, so they are not
+           * unknown and must not be logged as dropped.
+           */
+
+          if (BUF->type != HTONS(ETH_P_1588) &&
+              BUF->type != HTONS(ETHTYPE_IP6))
+#endif
+            {
+              nwarn("WARNING: DROPPED Unknown type: %04x\n", BUF->type);
+            }
         }
 
       /* We are finished with the RX buffer.  NOTE:  If the buffer is

include/netinet/if_ether.h

@@ -51,6 +51,7 @@
 #define ETH_P_IPV6  ETHERTYPE_IPV6
 #define ETH_P_ARP   ETHERTYPE_ARP
 #define ETH_P_TSN   0x22F0  /* TSN (IEEE 1722) packet */
+#define ETH_P_1588  0x88F7  /* PTP (IEEE 1588) over Ethernet packet */
 
 /****************************************************************************
  * Public Type Definitions