add tftpboot test for mips

pkgs/kernel/default.nix

@@ -51,6 +51,7 @@ stdenv.mkDerivation rec {
   patches = [
     ./cmdline-cookie.patch
     ./phram-allow-cached-mappings.patch
+    ./mips-malta-fdt-from-bootloader.patch
   ];
 
   # this is here to work around what I think is a bug in nixpkgs

pkgs/kernel/mips-malta-fdt-from-bootloader.patch

@@ -0,0 +1,18 @@
+diff --git a/arch/mips/mti-malta/malta-setup.c b/arch/mips/mti-malta/malta-setup.c
+index 21cb3ac1237b..f11409ae9583 100644
+--- a/arch/mips/mti-malta/malta-setup.c
++++ b/arch/mips/mti-malta/malta-setup.c
+@@ -192,7 +192,12 @@ static void __init bonito_quirks_setup(void)
+ 
+ void __init *plat_get_fdt(void)
+ {
+-	return (void *)__dtb_start;
++    void *r=0;
++    if(fw_arg0 == -2)
++	r = (void *) KSEG1ADDR(fw_arg1);
++    else
++	r = (void *)  __dtb_start;
++    return r;
+ }
+ 
+ void __init plat_mem_setup(void)

pkgs/u-boot/0002-virtio-init-for-malta.patch

@@ -0,0 +1,15 @@
+diff --git a/board/imgtec/malta/malta.c b/board/imgtec/malta/malta.c
+index 9853a0ba82..d95e332d6d 100644
+--- a/board/imgtec/malta/malta.c
++++ b/board/imgtec/malta/malta.c
+@@ -169,7 +169,9 @@ int board_early_init_f(void)
+ int misc_init_r(void)
+ {
+ 	rtc_reset();
+-
++#if IS_ENABLED(CONFIG_VIRTIO)
++	virtio_init();
++#endif
+ 	return 0;
+ }
+