Add the '--enable-print-device-tree' argument

I'm trying to debug some device tree problems while booting Linux and
figured it would be really nice to have access to the device tree while
trying to debug these problems.  I think this might be useful for lots
of people, so I went ahead and cleaned up the code enough that it should
actaully work in most cases.

1 files changed, 8 insertions, 3 deletions

diff --git a/bbl/bbl.c b/bbl/bbl.c
index b0a862d..7d1be2a 100644
--- a/bbl/bbl.c
+++ b/bbl/bbl.c
@@ -17,7 +17,7 @@ static uintptr_t dtb_output()
   return (end + MEGAPAGE_SIZE - 1) / MEGAPAGE_SIZE * MEGAPAGE_SIZE;
 }
 
-static void filter_dtb(uintptr_t source)
+static uintptr_t filter_dtb(uintptr_t source)
 {
   uintptr_t dest = dtb_output();
   uint32_t size = fdt_size(source);
@@ -28,6 +28,8 @@ static void filter_dtb(uintptr_t source)
   filter_plic(dest);
   filter_compat(dest, "riscv,clint0");
   filter_compat(dest, "riscv,debug-013");
+
+  return dest;
 }
 
 void boot_other_hart(uintptr_t dtb)
@@ -37,16 +39,19 @@ void boot_other_hart(uintptr_t dtb)
     entry = entry_point;
     mb();
   } while (!entry);
-  enter_supervisor_mode(entry, read_csr(mhartid), dtb_output());
+  enter_supervisor_mode(entry, read_csr(mhartid), dtb);
 }
 
 void boot_loader(uintptr_t dtb)
 {
   extern char _payload_start;
-  filter_dtb(dtb);
+  dtb = filter_dtb(dtb);
 #ifdef PK_ENABLE_LOGO
   print_logo();
 #endif
+#ifdef PK_PRINT_DEVICE_TREE
+  fdt_print(dtb);
+#endif
   mb();
   entry_point = &_payload_start;
   boot_other_hart(dtb);