efi_loader: Add network access support

We can now successfully boot EFI applications from disk, but users
may want to also run them from a PXE setup.

This patch implements rudimentary network support, allowing a payload
to send and receive network packets.

With this patch, I was able to successfully run grub2 with network
access inside of QEMU's -M xlnx-ep108.

Signed-off-by: Alexander Graf <agraf@suse.de>

net/bootp.c

@@ -10,6 +10,7 @@
 
 #include <common.h>
 #include <command.h>
+#include <efi_loader.h>
 #include <net.h>
 #include <net/tftp.h>
 #include "bootp.h"
@@ -1025,6 +1026,7 @@ static void dhcp_handler(uchar *pkt, unsigned dest, struct in_addr sip,
 			    strlen(CONFIG_SYS_BOOTFILE_PREFIX)) == 0) {
 #endif	/* CONFIG_SYS_BOOTFILE_PREFIX */
 			dhcp_packet_process_options(bp);
+			efi_net_set_dhcp_ack(pkt, len);
 
 			debug("TRANSITIONING TO REQUESTING STATE\n");
 			dhcp_state = REQUESTING;

net/net.c

@@ -146,7 +146,7 @@ static unsigned	net_ip_id;
 /* Ethernet bcast address */
 const u8 net_bcast_ethaddr[6] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 const u8 net_null_ethaddr[6];
-#ifdef CONFIG_API
+#if defined(CONFIG_API) || defined(CONFIG_EFI_LOADER)
 void (*push_packet)(void *, int len) = 0;
 #endif
 /* Network loop state */
@@ -1054,7 +1054,7 @@ void net_process_received_packet(uchar *in_packet, int len)
 	if (len < ETHER_HDR_SIZE)
 		return;
 
-#ifdef CONFIG_API
+#if defined(CONFIG_API) || defined(CONFIG_EFI_LOADER)
 	if (push_packet) {
 		(*push_packet)(in_packet, len);
 		return;

net/tftp.c

@@ -8,6 +8,7 @@
 
 #include <common.h>
 #include <command.h>
+#include <efi_loader.h>
 #include <mapmem.h>
 #include <net.h>
 #include <net/tftp.h>
@@ -804,6 +805,7 @@ void tftp_start(enum proto_t protocol)
 		printf("Load address: 0x%lx\n", load_addr);
 		puts("Loading: *\b");
 		tftp_state = STATE_SEND_RRQ;
+		efi_set_bootdev("Net", "", tftp_filename);
 	}
 
 	time_start = get_timer(0);