grub2/0020-Add-support-for-device-tree-based-drivers.patch

From fcbb723d4b1f7ad4687191562621dd0eb25f4d9e Mon Sep 17 00:00:00 2001
From: Vladimir Serbinenko <phcoder@gmail.com>
Date: Mon, 8 May 2017 21:19:59 +0200
Subject: [PATCH 020/236] Add support for device-tree-based drivers.

---
 grub-core/Makefile.core.def        |   2 +
 grub-core/bus/fdt.c                | 255 +++++++++++++++++++++++++++++++++++++
 grub-core/kern/arm/coreboot/init.c |  20 +++
 grub-core/lib/fdt.c                | 152 ++++++++++++++++------
 util/grub-install-common.c         |   2 +-
 util/grub-mkimage.c                |  11 +-
 util/mkimage.c                     |  24 +++-
 include/grub/fdt.h                 |  23 ++--
 include/grub/fdtbus.h              |  73 +++++++++++
 include/grub/kernel.h              |   3 +-
 include/grub/util/install.h        |   2 +-
 conf/Makefile.common               |   4 +-
 grub-core/Makefile.am              |  10 ++
 13 files changed, 524 insertions(+), 57 deletions(-)
 create mode 100644 grub-core/bus/fdt.c
 create mode 100644 include/grub/fdtbus.h

diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
index 411dca46bf2..77d0b019eb2 100644
--- a/grub-core/Makefile.core.def
+++ b/grub-core/Makefile.core.def
@@ -158,6 +158,8 @@ kernel = {
   arm_coreboot = kern/arm/coreboot/init.c;
   arm_coreboot = kern/arm/coreboot/timer.c;
   arm_coreboot = kern/arm/coreboot/coreboot.S;
+  arm_coreboot = lib/fdt.c;
+  arm_coreboot = bus/fdt.c;
 
   terminfoinkernel = term/terminfo.c;
   terminfoinkernel = term/tparm.c;
diff --git a/grub-core/bus/fdt.c b/grub-core/bus/fdt.c
new file mode 100644
index 00000000000..6fb077000a5
--- /dev/null
+++ b/grub-core/bus/fdt.c
@@ -0,0 +1,255 @@
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2016  Free Software Foundation, Inc.
+ *
+ *  GRUB is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  GRUB is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <grub/fdtbus.h>
+#include <grub/fdt.h>
+#include <grub/term.h>
+
+static const void *dtb;
+static grub_size_t root_address_cells, root_size_cells;
+/* Pointer to this symbol signals invalid mapping.  */
+char grub_fdtbus_invalid_mapping[1];
+
+struct grub_fdtbus_dev
+{
+  struct grub_fdtbus_dev *next;
+  struct grub_fdtbus_dev *parent;
+  int node;
+  struct grub_fdtbus_driver *driver;
+};
+
+struct grub_fdtbus_dev *devs;
+struct grub_fdtbus_driver *drivers;
+
+static int
+is_compatible (struct grub_fdtbus_driver *driver,
+	       int node)
+{
+  grub_size_t compatible_size;
+  const char *compatible = grub_fdt_get_prop (dtb, node, "compatible",
+					      &compatible_size);
+  const char *compatible_end = compatible + compatible_size;
+  while (compatible < compatible_end)
+    {
+      if (grub_strcmp (driver->compatible, compatible) == 0)
+	return 1;
+      compatible += grub_strlen (compatible) + 1;
+    }
+  return 0;
+}
+
+static void
+fdtbus_scan (struct grub_fdtbus_dev *parent)
+{
+  int node;
+  for (node = grub_fdt_first_node (dtb, parent ? parent->node : 0); node >= 0;
+       node = grub_fdt_next_node (dtb, node))
+    {
+      struct grub_fdtbus_dev *dev;
+      struct grub_fdtbus_driver *driver;
+      dev = grub_zalloc (sizeof (*dev));
+      if (!dev)
+	{
+	  grub_print_error ();
+	  return;
+	}
+      dev->node = node;
+      dev->next = devs;
+      dev->parent = parent;
+      devs = dev;
+      FOR_LIST_ELEMENTS(driver, drivers)
+	if (!dev->driver && is_compatible (driver, node))
+	  {
+	    if (driver->attach(dev) == GRUB_ERR_NONE)
+	      {
+		dev->driver = driver;
+		break;
+	      }
+	    grub_print_error ();
+	  }
+      fdtbus_scan (dev);
+    }
+}
+
+void
+grub_fdtbus_register (struct grub_fdtbus_driver *driver)
+{
+  struct grub_fdtbus_dev *dev;
+  grub_list_push (GRUB_AS_LIST_P (&drivers),
+		  GRUB_AS_LIST (driver));
+  for (dev = devs; dev; dev = dev->next)
+    if (!dev->driver && is_compatible (driver, dev->node))
+      {
+	if (driver->attach(dev) == GRUB_ERR_NONE)
+	  dev->driver = driver;
+	grub_print_error ();
+      }
+}
+
+void
+grub_fdtbus_unregister (struct grub_fdtbus_driver *driver)
+{
+  grub_list_remove (GRUB_AS_LIST (driver));
+  struct grub_fdtbus_dev *dev;
+  for (dev = devs; dev; dev = dev->next)
+    if (dev->driver == driver)
+      {
+	if (driver->detach)
+	  driver->detach(dev);
+	dev->driver = 0;
+      }
+}
+
+void
+grub_fdtbus_init (const void *dtb_in, grub_size_t size)
+{
+  if (!dtb_in || grub_fdt_check_header (dtb_in, size) < 0)
+    grub_fatal ("invalid FDT");
+  dtb = dtb_in;
+  const grub_uint32_t *prop = grub_fdt_get_prop (dtb, 0, "#address-cells", 0);
+  if (prop)
+    root_address_cells = grub_be_to_cpu32 (*prop);
+  else
+    root_address_cells = 1;
+
+  prop = grub_fdt_get_prop (dtb, 0, "#size-cells", 0);
+  if (prop)
+    root_size_cells = grub_be_to_cpu32 (*prop);
+  else
+    root_size_cells = 1;
+
+  fdtbus_scan (0);
+}
+
+static int
+get_address_cells (const struct grub_fdtbus_dev *dev)
+{
+  const grub_uint32_t *prop;
+  if (!dev)
+    return root_address_cells;
+  prop = grub_fdt_get_prop (dtb, dev->node, "#address-cells", 0);
+  if (prop)
+    return grub_be_to_cpu32 (*prop);
+  return 1;
+}
+
+static int
+get_size_cells (const struct grub_fdtbus_dev *dev)
+{
+  const grub_uint32_t *prop;
+  if (!dev)
+    return root_size_cells;
+  prop = grub_fdt_get_prop (dtb, dev->node, "#size-cells", 0);
+  if (prop)
+    return grub_be_to_cpu32 (*prop);
+  return 1;
+}
+
+static grub_uint64_t
+get64 (const grub_uint32_t *reg, grub_size_t cells)
+{
+  grub_uint64_t val = 0;
+  if (cells >= 1)
+    val = grub_be_to_cpu32 (reg[cells - 1]);
+  if (cells >= 2)
+    val |= ((grub_uint64_t) grub_be_to_cpu32 (reg[cells - 2])) << 32;
+  return val;
+}
+
+static volatile void *
+translate (const struct grub_fdtbus_dev *dev, const grub_uint32_t *reg)
+{
+  volatile void *ret;
+  const grub_uint32_t *ranges;
+  grub_size_t ranges_size, cells_per_mapping;
+  grub_size_t parent_address_cells, child_address_cells, child_size_cells;
+  grub_size_t nmappings, i;
+  if (dev == 0)
+    {
+      grub_uint64_t val;
+      val = get64 (reg, root_address_cells);
+      if (sizeof (void *) == 4 && (val >> 32))
+	return grub_fdtbus_invalid_mapping;
+      return (void *) (grub_addr_t) val;
+    }
+  ranges = grub_fdt_get_prop (dtb, dev->node, "ranges", &ranges_size);
+  if (!ranges)
+    return grub_fdtbus_invalid_mapping;
+  if (ranges_size == 0)
+    return translate (dev->parent, reg);
+  parent_address_cells = get_address_cells (dev->parent);
+  child_address_cells = get_address_cells (dev);
+  child_size_cells = get_size_cells (dev);
+  cells_per_mapping = parent_address_cells + child_address_cells + child_size_cells;
+  nmappings = ranges_size / 4 / cells_per_mapping;
+  for (i = 0; i < nmappings; i++)
+    {
+      const grub_uint32_t *child_addr = &ranges[i * cells_per_mapping];
+      const grub_uint32_t *parent_addr = child_addr + child_address_cells;
+      grub_uint64_t child_size = get64 (parent_addr + parent_address_cells, child_size_cells);
+
+      if (child_address_cells > 2 && grub_memcmp (reg, child_addr, (child_address_cells - 2) * 4) != 0)
+	continue;
+      if (get64 (reg, child_address_cells) < get64 (child_addr, child_address_cells))
+	continue;
+
+      grub_uint64_t offset = get64 (reg, child_address_cells) - get64 (child_addr, child_address_cells);
+      if (offset >= child_size)
+	continue;
+
+      ret = translate (dev->parent, parent_addr);
+      if (grub_fdtbus_is_mapping_valid (ret))
+	ret = (volatile char *) ret + offset;
+      return ret;
+    }
+  return grub_fdtbus_invalid_mapping;
+}
+
+volatile void *
+grub_fdtbus_map_reg (const struct grub_fdtbus_dev *dev, int regno, grub_size_t *size)
+{
+  grub_size_t address_cells, size_cells;
+  address_cells = get_address_cells (dev->parent);
+  size_cells = get_size_cells (dev->parent);
+  const grub_uint32_t *reg = grub_fdt_get_prop (dtb, dev->node, "reg", 0);
+  if (size && size_cells)
+    *size = reg[(address_cells + size_cells) * regno + address_cells];
+  if (size && !size_cells)
+    *size = 0;
+  return translate (dev->parent, reg + (address_cells + size_cells) * regno);
+}
+
+const char *
+grub_fdtbus_get_name (const struct grub_fdtbus_dev *dev)
+{
+  return grub_fdt_get_nodename (dtb, dev->node);
+}
+
+const void *
+grub_fdtbus_get_prop (const struct grub_fdtbus_dev *dev,
+		      const char *name,
+		      grub_uint32_t *len)
+{
+  return grub_fdt_get_prop (dtb, dev->node, name, len);
+}
+
+const void *
+grub_fdtbus_get_fdt (void)
+{
+  return dtb;
+}
diff --git a/grub-core/kern/arm/coreboot/init.c b/grub-core/kern/arm/coreboot/init.c
index 51ecaceb005..aec75c672a2 100644
--- a/grub-core/kern/arm/coreboot/init.c
+++ b/grub-core/kern/arm/coreboot/init.c
@@ -33,6 +33,7 @@
 #include <grub/symbol.h>
 #include <grub/video.h>
 #include <grub/coreboot/lbio.h>
+#include <grub/fdtbus.h>
 
 extern grub_uint8_t _start[];
 extern grub_uint8_t _end[];
@@ -99,6 +100,10 @@ heap_init (grub_uint64_t addr, grub_uint64_t size, grub_memory_type_t type,
 void
 grub_machine_init (void)
 {
+  struct grub_module_header *header;
+  void *dtb = 0;
+  grub_size_t dtb_size = 0;
+
   modend = grub_modules_get_end ();
 
   grub_video_coreboot_fb_early_init ();
@@ -112,6 +117,21 @@ grub_machine_init (void)
   grub_font_init ();
   grub_gfxterm_init ();
 
+  FOR_MODULES (header)
+    if (header->type == OBJ_TYPE_DTB)
+      {
+	char *dtb_orig_addr, *dtb_copy;
+	dtb_orig_addr = (char *) header + sizeof (struct grub_module_header);
+
+	dtb_size = header->size - sizeof (struct grub_module_header);
+	dtb = dtb_copy = grub_malloc (dtb_size);
+	grub_memmove (dtb_copy, dtb_orig_addr, dtb_size);
+	break;
+      }
+  if (!dtb)
+    grub_fatal ("No DTB found");
+  grub_fdtbus_init (dtb, dtb_size);
+
   grub_machine_timer_init ();
 }
 
diff --git a/grub-core/lib/fdt.c b/grub-core/lib/fdt.c
index b5d520f2088..bdc6302448d 100644
--- a/grub-core/lib/fdt.c
+++ b/grub-core/lib/fdt.c
@@ -102,13 +102,13 @@ static grub_uint32_t *get_next_node (const void *fdt, char *node_name)
 static int get_mem_rsvmap_size (const void *fdt)
 {
   int size = 0;
-  grub_uint64_t *ptr = (void *) ((grub_addr_t) fdt
-                                 + grub_fdt_get_off_mem_rsvmap (fdt));
+  grub_unaligned_uint64_t *ptr = (void *) ((grub_addr_t) fdt
+					   + grub_fdt_get_off_mem_rsvmap (fdt));
 
   do
   {
     size += 2 * sizeof(*ptr);
-    if (!*ptr && !*(ptr + 1))
+    if (!ptr[0].val && !ptr[1].val)
       return size;
     ptr += 2;
   } while ((grub_addr_t) ptr <= (grub_addr_t) fdt + grub_fdt_get_totalsize (fdt)
@@ -229,7 +229,7 @@ static int rearrange_blocks (void *fdt, unsigned int clearance)
   return 0;
 }
 
-static grub_uint32_t *find_prop (void *fdt, unsigned int nodeoffset,
+static grub_uint32_t *find_prop (const void *fdt, unsigned int nodeoffset,
 				 const char *name)
 {
   grub_uint32_t *prop = (void *) ((grub_addr_t) fdt
@@ -268,9 +268,9 @@ static grub_uint32_t *find_prop (void *fdt, unsigned int nodeoffset,
    the size allocated for the FDT; if this function is called before the other
    functions in this file and returns success, the other functions are
    guaranteed not to access memory locations outside the allocated memory. */
-int grub_fdt_check_header_nosize (void *fdt)
+int grub_fdt_check_header_nosize (const void *fdt)
 {
-  if (((grub_addr_t) fdt & 0x7) || (grub_fdt_get_magic (fdt) != FDT_MAGIC)
+  if (((grub_addr_t) fdt & 0x3) || (grub_fdt_get_magic (fdt) != FDT_MAGIC)
       || (grub_fdt_get_version (fdt) < FDT_SUPPORTED_VERSION)
       || (grub_fdt_get_last_comp_version (fdt) > FDT_SUPPORTED_VERSION)
       || (grub_fdt_get_off_dt_struct (fdt) & 0x00000003)
@@ -286,7 +286,7 @@ int grub_fdt_check_header_nosize (void *fdt)
   return 0;
 }
 
-int grub_fdt_check_header (void *fdt, unsigned int size)
+int grub_fdt_check_header (const void *fdt, unsigned int size)
 {
   if (size < sizeof (grub_fdt_header_t)
       || (grub_fdt_get_totalsize (fdt) > size)
@@ -295,52 +295,104 @@ int grub_fdt_check_header (void *fdt, unsigned int size)
   return 0;
 }
 
+static const grub_uint32_t *
+advance_token (const void *fdt, const grub_uint32_t *token, const grub_uint32_t *end, int skip_current)
+{
+  for (; token < end; skip_current = 0)
+  {
+    switch (grub_be_to_cpu32 (*token))
+    {
+      case FDT_BEGIN_NODE:
+	if (skip_current)
+	  {
+	    token = get_next_node (fdt, (char *) (token + 1));
+	    continue;
+	  }
+	char *ptr;
+	for (ptr = (char *) (token + 1); *ptr && ptr < (char *) end; ptr++);
+        if (ptr >= (char *) end)
+          return 0;
+	return token;
+      case FDT_PROP:
+        /* Skip property token and following data (len, nameoff and property
+           value). */
+        if (token >= end - 1)
+          return 0;
+        token += prop_entry_size(grub_be_to_cpu32(*(token + 1)))
+                 / sizeof(*token);
+        break;
+      case FDT_NOP:
+        token++;
+        break;
+      default:
+        return 0;
+    }
+  }
+  return 0;
+}
+
+int grub_fdt_next_node (const void *fdt, unsigned int currentoffset)
+{
+  const grub_uint32_t *token = (const grub_uint32_t *) fdt + (currentoffset + grub_fdt_get_off_dt_struct (fdt)) / 4;
+  token = advance_token (fdt, token, (const void *) struct_end (fdt), 1);
+  if (!token)
+    return -1;
+  return (int) ((grub_addr_t) token - (grub_addr_t) fdt
+		- grub_fdt_get_off_dt_struct (fdt));
+}			 
+
+int grub_fdt_first_node (const void *fdt, unsigned int parentoffset)
+{
+  const grub_uint32_t *token, *end;
+  char *node_name;
+
+  if (parentoffset & 0x3)
+    return -1;
+  token = (const void *) ((grub_addr_t) fdt + grub_fdt_get_off_dt_struct(fdt)
+                    + parentoffset);
+  end = (const void *) struct_end (fdt);
+  if ((token >= end) || (grub_be_to_cpu32(*token) != FDT_BEGIN_NODE))
+    return -1;
+  SKIP_NODE_NAME(node_name, token, end);
+  token = advance_token (fdt, token, end, 0);
+  if (!token)
+    return -1;
+  return (int) ((grub_addr_t) token - (grub_addr_t) fdt
+		- grub_fdt_get_off_dt_struct (fdt));
+}			 
+
 /* Find a direct sub-node of a given parent node. */
 int grub_fdt_find_subnode (const void *fdt, unsigned int parentoffset,
 			   const char *name)
 {
-  grub_uint32_t *token, *end;
-  char *node_name;
+  const grub_uint32_t *token, *end;
+  const char *node_name;
+  int skip_current = 0;
 
   if (parentoffset & 0x3)
     return -1;
-  token = (void *) ((grub_addr_t) fdt + grub_fdt_get_off_dt_struct(fdt)
+  token = (const void *) ((grub_addr_t) fdt + grub_fdt_get_off_dt_struct(fdt)
                     + parentoffset);
-  end = (void *) struct_end (fdt);
+  end = (const void *) struct_end (fdt);
   if ((token >= end) || (grub_be_to_cpu32(*token) != FDT_BEGIN_NODE))
     return -1;
   SKIP_NODE_NAME(node_name, token, end);
-  while (token < end)
-  {
-    switch (grub_be_to_cpu32(*token))
-    {
-      case FDT_BEGIN_NODE:
-        node_name = (char *) (token + 1);
-        if (node_name + grub_strlen (name) >= (char *) end)
-          return -1;
-        if (!grub_strcmp (node_name, name))
-          return (int) ((grub_addr_t) token - (grub_addr_t) fdt
-                        - grub_fdt_get_off_dt_struct (fdt));
-        token = get_next_node (fdt, node_name);
-        if (!token)
-          return -1;
-        break;
-      case FDT_PROP:
-        /* Skip property token and following data (len, nameoff and property
-           value). */
-        if (token >= end - 1)
-          return -1;
-        token += prop_entry_size(grub_be_to_cpu32(*(token + 1)))
-                 / sizeof(*token);
-        break;
-      case FDT_NOP:
-        token++;
-        break;
-      default:
-        return -1;
-    }
+  while (1) {
+    token = advance_token (fdt, token, end, skip_current);
+    if (!token)
+      return -1;
+    skip_current = 1;
+    node_name = (const char *) token + 4;
+    if (grub_strcmp (node_name, name) == 0)
+      return (int) ((grub_addr_t) token - (grub_addr_t) fdt
+		    - grub_fdt_get_off_dt_struct (fdt));
   }
-  return -1;
+}
+
+const char *
+grub_fdt_get_nodename (const void *fdt, unsigned int nodeoffset)
+{
+  return (const char *) fdt + grub_fdt_get_off_dt_struct(fdt) + nodeoffset + 4;
 }
 
 int grub_fdt_add_subnode (void *fdt, unsigned int parentoffset,
@@ -359,6 +411,24 @@ int grub_fdt_add_subnode (void *fdt, unsigned int parentoffset,
   return add_subnode (fdt, parentoffset, name);
 }
 
+const void *
+grub_fdt_get_prop (const void *fdt, unsigned int nodeoffset, const char *name,
+		   grub_uint32_t *len)
+{
+  grub_uint32_t *prop;
+  if ((nodeoffset >= grub_fdt_get_size_dt_struct (fdt)) || (nodeoffset & 0x3)
+      || (grub_be_to_cpu32(*(grub_uint32_t *) ((grub_addr_t) fdt
+					       + grub_fdt_get_off_dt_struct (fdt) + nodeoffset))
+          != FDT_BEGIN_NODE))
+    return 0;
+  prop = find_prop (fdt, nodeoffset, name);
+  if (!prop)
+    return 0;
+  if (len)
+    *len = grub_be_to_cpu32 (*(prop + 1));
+  return prop + 3;
+}
+
 int grub_fdt_set_prop (void *fdt, unsigned int nodeoffset, const char *name,
 		       const void *val, grub_uint32_t len)
 {
diff --git a/util/grub-install-common.c b/util/grub-install-common.c
index 452b230daed..8539ff3484d 100644
--- a/util/grub-install-common.c
+++ b/util/grub-install-common.c
@@ -499,7 +499,7 @@ grub_install_make_image_wrap_file (const char *dir, const char *prefix,
   grub_install_generate_image (dir, prefix, fp, outname,
 			       modules.entries, memdisk_path,
 			       pubkeys, npubkeys, config_path, tgt,
-			       note, compression);
+			       note, compression, 0);
   while (dc--)
     grub_install_pop_module ();
 }
diff --git a/util/grub-mkimage.c b/util/grub-mkimage.c
index aba19d21b9a..98d24cc06ea 100644
--- a/util/grub-mkimage.c
+++ b/util/grub-mkimage.c
@@ -71,6 +71,7 @@ static struct argp_option options[] = {
    N_("embed FILE as a memdisk image\n"
       "Implies `-p (memdisk)/boot/grub' and overrides any prefix supplied previously,"
       " but the prefix itself can be overridden by later options"), 0},
+  {"dtb",  'D', N_("FILE"), 0, N_("embed FILE as a device tree (DTB)\n"), 0},
    /* TRANSLATORS: "embed" is a verb (command description).  "*/
   {"config",   'c', N_("FILE"), 0, N_("embed FILE as an early config"), 0},
    /* TRANSLATORS: "embed" is a verb (command description).  "*/
@@ -117,6 +118,7 @@ struct arguments
   char *dir;
   char *prefix;
   char *memdisk;
+  char *dtb;
   char **pubkeys;
   size_t npubkeys;
   char *font;
@@ -176,6 +178,13 @@ argp_parser (int key, char *arg, struct argp_state *state)
       arguments->prefix = xstrdup ("(memdisk)/boot/grub");
       break;
 
+    case 'D':
+      if (arguments->dtb)
+	free (arguments->dtb);
+
+      arguments->dtb = xstrdup (arg);
+      break;
+
     case 'k':
       arguments->pubkeys = xrealloc (arguments->pubkeys,
 				     sizeof (arguments->pubkeys[0])
@@ -300,7 +309,7 @@ main (int argc, char *argv[])
 			       arguments.memdisk, arguments.pubkeys,
 			       arguments.npubkeys, arguments.config,
 			       arguments.image_target, arguments.note,
-			       arguments.comp);
+			       arguments.comp, arguments.dtb);
 
   grub_util_file_sync  (fp);
   fclose (fp);
diff --git a/util/mkimage.c b/util/mkimage.c
index 6aa77ed7367..e22d82afa61 100644
--- a/util/mkimage.c
+++ b/util/mkimage.c
@@ -777,13 +777,12 @@ grub_install_generate_image (const char *dir, const char *prefix,
 			     char *memdisk_path, char **pubkey_paths,
 			     size_t npubkeys, char *config_path,
 			     const struct grub_install_image_target_desc *image_target,
-			     int note,
-			     grub_compression_t comp)
+			     int note, grub_compression_t comp, const char *dtb_path)
 {
   char *kernel_img, *core_img;
   size_t total_module_size, core_size;
   size_t memdisk_size = 0, config_size = 0;
-  size_t prefix_size = 0;
+  size_t prefix_size = 0, dtb_size = 0;
   char *kernel_path;
   size_t offset;
   struct grub_util_path_list *path_list, *p;
@@ -828,6 +827,12 @@ grub_install_generate_image (const char *dir, const char *prefix,
       total_module_size += memdisk_size + sizeof (struct grub_module_header);
     }
 
+  if (dtb_path)
+    {
+      dtb_size = ALIGN_UP(grub_util_get_image_size (dtb_path), 4);
+      total_module_size += dtb_size + sizeof (struct grub_module_header);
+    }
+
   if (config_path)
     {
       config_size = ALIGN_ADDR (grub_util_get_image_size (config_path) + 1);
@@ -950,6 +955,19 @@ grub_install_generate_image (const char *dir, const char *prefix,
       offset += memdisk_size;
     }
 
+  if (dtb_path)
+    {
+      struct grub_module_header *header;
+
+      header = (struct grub_module_header *) (kernel_img + offset);
+      header->type = grub_host_to_target32 (OBJ_TYPE_DTB);
+      header->size = grub_host_to_target32 (dtb_size + sizeof (*header));
+      offset += sizeof (*header);
+
+      grub_util_load_image (dtb_path, kernel_img + offset);
+      offset += dtb_size;
+    }
+
   if (config_path)
     {
       struct grub_module_header *header;
diff --git a/include/grub/fdt.h b/include/grub/fdt.h
index fdfca75bf48..75525fa317c 100644
--- a/include/grub/fdt.h
+++ b/include/grub/fdt.h
@@ -20,6 +20,7 @@
 #define GRUB_FDT_HEADER	1
 
 #include <grub/types.h>
+#include <grub/symbol.h>
 
 #define FDT_MAGIC 0xD00DFEED
 
@@ -95,16 +96,22 @@ struct grub_fdt_empty_tree {
 #define grub_fdt_set_size_dt_struct(fdt, value)	\
 	grub_fdt_set_header(fdt, size_dt_struct, value)
 
-int grub_fdt_create_empty_tree (void *fdt, unsigned int size);
-int grub_fdt_check_header (void *fdt, unsigned int size);
-int grub_fdt_check_header_nosize (void *fdt);
-int grub_fdt_find_subnode (const void *fdt, unsigned int parentoffset,
-			   const char *name);
-int grub_fdt_add_subnode (void *fdt, unsigned int parentoffset,
+int EXPORT_FUNC(grub_fdt_create_empty_tree) (void *fdt, unsigned int size);
+int EXPORT_FUNC(grub_fdt_check_header) (const void *fdt, unsigned int size);
+int EXPORT_FUNC(grub_fdt_check_header_nosize) (const void *fdt);
+int EXPORT_FUNC(grub_fdt_find_subnode) (const void *fdt, unsigned int parentoffset,
+					const char *name);
+int EXPORT_FUNC(grub_fdt_first_node) (const void *fdt, unsigned int parentoffset);
+int EXPORT_FUNC(grub_fdt_next_node) (const void *fdt, unsigned int currentoffset);
+int EXPORT_FUNC(grub_fdt_add_subnode) (void *fdt, unsigned int parentoffset,
 			  const char *name);
+const char *
+EXPORT_FUNC(grub_fdt_get_nodename) (const void *fdt, unsigned int nodeoffset);
+const void *EXPORT_FUNC(grub_fdt_get_prop) (const void *fdt, unsigned int nodeoffset, const char *name,
+					    grub_uint32_t *len);
 
-int grub_fdt_set_prop (void *fdt, unsigned int nodeoffset, const char *name,
-		      const void *val, grub_uint32_t len);
+int EXPORT_FUNC(grub_fdt_set_prop) (void *fdt, unsigned int nodeoffset, const char *name,
+				    const void *val, grub_uint32_t len);
 #define grub_fdt_set_prop32(fdt, nodeoffset, name, val)	\
 ({ \
   grub_uint32_t _val = grub_cpu_to_be32(val); \
diff --git a/include/grub/fdtbus.h b/include/grub/fdtbus.h
new file mode 100644
index 00000000000..985837e55f6
--- /dev/null
+++ b/include/grub/fdtbus.h
@@ -0,0 +1,73 @@
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2016  Free Software Foundation, Inc.
+ *
+ *  GRUB is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  GRUB is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef GRUB_FDTBUS_HEADER
+#define GRUB_FDTBUS_HEADER	1
+
+#include <grub/fdt.h>
+#include <grub/err.h>
+
+struct grub_fdtbus_dev;
+
+struct grub_fdtbus_driver
+{
+  struct grub_fdtbus_driver *next;
+  struct grub_fdtbus_driver **prev;
+
+  const char *compatible;
+
+  grub_err_t (*attach) (const struct grub_fdtbus_dev *dev);
+  void (*detach) (const struct grub_fdtbus_dev *dev);
+};
+
+extern char EXPORT_VAR(grub_fdtbus_invalid_mapping)[1];
+
+static inline int
+grub_fdtbus_is_mapping_valid (volatile void *m)
+{
+  return m != grub_fdtbus_invalid_mapping;
+}
+
+volatile void *
+EXPORT_FUNC(grub_fdtbus_map_reg) (const struct grub_fdtbus_dev *dev, int reg, grub_size_t *size);
+
+const void *
+EXPORT_FUNC(grub_fdtbus_get_fdt) (void);
+
+const char *
+EXPORT_FUNC(grub_fdtbus_get_name) (const struct grub_fdtbus_dev *dev);
+
+const void *
+EXPORT_FUNC(grub_fdtbus_get_prop) (const struct grub_fdtbus_dev *dev,
+		      const char *name,
+		      grub_uint32_t *len);
+
+void
+EXPORT_FUNC(grub_fdtbus_register) (struct grub_fdtbus_driver *driver);
+
+void
+EXPORT_FUNC(grub_fdtbus_unregister) (struct grub_fdtbus_driver *driver);
+
+/* Must be called before any register(). */
+/* dtb is assumed to be unfreeable and must remain
+   valid for lifetime of GRUB.
+ */
+void
+grub_fdtbus_init (const void *dtb, grub_size_t size);
+
+#endif
diff --git a/include/grub/kernel.h b/include/grub/kernel.h
index 20ddf2da297..ecd88ca72c6 100644
--- a/include/grub/kernel.h
+++ b/include/grub/kernel.h
@@ -28,7 +28,8 @@ enum
   OBJ_TYPE_MEMDISK,
   OBJ_TYPE_CONFIG,
   OBJ_TYPE_PREFIX,
-  OBJ_TYPE_PUBKEY
+  OBJ_TYPE_PUBKEY,
+  OBJ_TYPE_DTB
 };
 
 /* The module header.  */
diff --git a/include/grub/util/install.h b/include/grub/util/install.h
index 5ca4811cd13..6abd288c313 100644
--- a/include/grub/util/install.h
+++ b/include/grub/util/install.h
@@ -176,7 +176,7 @@ grub_install_generate_image (const char *dir, const char *prefix,
 			     char *config_path,
 			     const struct grub_install_image_target_desc *image_target,
 			     int note,
-			     grub_compression_t comp);
+			     grub_compression_t comp, const char *dtb_file);
 
 const struct grub_install_image_target_desc *
 grub_install_get_image_target (const char *arg);
diff --git a/conf/Makefile.common b/conf/Makefile.common
index 11296b550a7..311da61c6c5 100644
--- a/conf/Makefile.common
+++ b/conf/Makefile.common
@@ -86,9 +86,11 @@ CPPFLAGS_TERMINAL_LIST += '-Dgrub_term_register_output(...)=OUTPUT_TERMINAL_LIST
 CPPFLAGS_COMMAND_LIST = '-Dgrub_register_command(...)=COMMAND_LIST_MARKER(__VA_ARGS__)'
 CPPFLAGS_COMMAND_LIST += '-Dgrub_register_extcmd(...)=EXTCOMMAND_LIST_MARKER(__VA_ARGS__)'
 CPPFLAGS_COMMAND_LIST += '-Dgrub_register_command_p1(...)=P1COMMAND_LIST_MARKER(__VA_ARGS__)'
+CPPFLAGS_FDT_LIST := '-Dgrub_fdtbus_register(...)=FDT_DRIVER_LIST_MARKER(__VA_ARGS__)'
 CPPFLAGS_MARKER = $(CPPFLAGS_FS_LIST) $(CPPFLAGS_VIDEO_LIST) \
 	$(CPPFLAGS_PARTTOOL_LIST) $(CPPFLAGS_PARTMAP_LIST) \
-	$(CPPFLAGS_TERMINAL_LIST) $(CPPFLAGS_COMMAND_LIST)
+	$(CPPFLAGS_TERMINAL_LIST) $(CPPFLAGS_COMMAND_LIST) \
+	$(CPPFLAGS_FDT_LIST)
 
 # Define these variables to calm down automake
 
diff --git a/grub-core/Makefile.am b/grub-core/Makefile.am
index bec0585549a..fc6ca305147 100644
--- a/grub-core/Makefile.am
+++ b/grub-core/Makefile.am
@@ -368,6 +368,16 @@ terminal.lst: $(MARKER_FILES)
 platform_DATA += terminal.lst
 CLEANFILES += terminal.lst
 
+fdt.lst: $(MARKER_FILES)
+	(for pp in $^; do \
+	  b=`basename $$pp .marker`; \
+	  sed -n \
+	    -e "/FDT_DRIVER_LIST_MARKER *( *\"/{s/.*( *\"\([^\"]*\)\".*/i\1: $$b/;p;}" \
+	    -e "/FDT_DRIVER_LIST_MARKER *( *\"/{s/.*( *\"\([^\"]*\)\".*/o\1: $$b/;p;}" $$pp; \
+	done) | sort -u > $@
+platform_DATA += fdt.lst
+CLEANFILES += fdt.lst
+
 parttool.lst: $(MARKER_FILES)
 	(for pp in $^; do \
 	  b=`basename $$pp .marker`; \
-- 
2.15.0