efi: move fdt helper library

There is nothing ARM64 (or even ARM) specific about the efi fdt helper
library, which is used for locating or overriding a firmware-provided
devicetree in a UEFI system - so move it to loader/efi for reuse.

Move the fdtload.h include file to grub/efi and update path to
efi/fdtload.h in source code referring to it.

Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>

grub-core/loader/efi/fdt.c

@@ -0,0 +1,163 @@
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2013-2015  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/fdt.h>
+#include <grub/mm.h>
+#include <grub/err.h>
+#include <grub/dl.h>
+#include <grub/command.h>
+#include <grub/file.h>
+#include <grub/efi/efi.h>
+#include <grub/efi/fdtload.h>
+
+static void *loaded_fdt;
+static void *fdt;
+
+void *
+grub_fdt_load (grub_size_t additional_size)
+{
+  void *raw_fdt;
+  grub_size_t size;
+
+  if (fdt)
+    {
+      size = GRUB_EFI_BYTES_TO_PAGES (grub_fdt_get_totalsize (fdt));
+      grub_efi_free_pages ((grub_efi_physical_address_t) fdt, size);
+    }
+
+  if (loaded_fdt)
+    raw_fdt = loaded_fdt;
+  else
+    raw_fdt = grub_efi_get_firmware_fdt();
+
+  size =
+    raw_fdt ? grub_fdt_get_totalsize (raw_fdt) : GRUB_FDT_EMPTY_TREE_SZ;
+  size += additional_size;
+
+  grub_dprintf ("linux", "allocating %ld bytes for fdt\n", size);
+  fdt = grub_efi_allocate_any_pages (GRUB_EFI_BYTES_TO_PAGES (size));
+  if (!fdt)
+    return NULL;
+
+  if (raw_fdt)
+    {
+      grub_memmove (fdt, raw_fdt, size);
+      grub_fdt_set_totalsize (fdt, size);
+    }
+  else
+    {
+      grub_fdt_create_empty_tree (fdt, size);
+    }
+  return fdt;
+}
+
+grub_err_t
+grub_fdt_install (void)
+{
+  grub_efi_boot_services_t *b;
+  grub_efi_guid_t fdt_guid = GRUB_EFI_DEVICE_TREE_GUID;
+  grub_efi_status_t status;
+
+  b = grub_efi_system_table->boot_services;
+  status = b->install_configuration_table (&fdt_guid, fdt);
+  if (status != GRUB_EFI_SUCCESS)
+    return grub_error (GRUB_ERR_IO, "failed to install FDT");
+
+  grub_dprintf ("fdt", "Installed/updated FDT configuration table @ %p\n",
+		fdt);
+  return GRUB_ERR_NONE;
+}
+
+void
+grub_fdt_unload (void) {
+  if (!fdt) {
+    return;
+  }
+  grub_efi_free_pages ((grub_efi_physical_address_t) fdt,
+		       GRUB_EFI_BYTES_TO_PAGES (grub_fdt_get_totalsize (fdt)));
+  fdt = NULL;
+}
+
+static grub_err_t
+grub_cmd_devicetree (grub_command_t cmd __attribute__ ((unused)),
+		     int argc, char *argv[])
+{
+  grub_file_t dtb;
+  void *blob = NULL;
+  int size;
+
+  if (loaded_fdt)
+    grub_free (loaded_fdt);
+  loaded_fdt = NULL;
+
+  /* No arguments means "use firmware FDT".  */
+  if (argc == 0)
+    {
+      return GRUB_ERR_NONE;
+    }
+
+  dtb = grub_file_open (argv[0]);
+  if (!dtb)
+    goto out;
+
+  size = grub_file_size (dtb);
+  blob = grub_malloc (size);
+  if (!blob)
+    goto out;
+
+  if (grub_file_read (dtb, blob, size) < size)
+    {
+      if (!grub_errno)
+	grub_error (GRUB_ERR_BAD_OS, N_("premature end of file %s"), argv[0]);
+      goto out;
+    }
+
+  if (grub_fdt_check_header (blob, size) != 0)
+    {
+      grub_error (GRUB_ERR_BAD_OS, N_("invalid device tree"));
+      goto out;
+    }
+
+out:
+  if (dtb)
+    grub_file_close (dtb);
+
+  if (blob)
+    {
+      if (grub_errno == GRUB_ERR_NONE)
+	loaded_fdt = blob;
+      else
+	grub_free (blob);
+    }
+
+  return grub_errno;
+}
+
+static grub_command_t cmd_devicetree;
+
+GRUB_MOD_INIT (fdt)
+{
+  cmd_devicetree =
+    grub_register_command ("devicetree", grub_cmd_devicetree, 0,
+			   N_("Load DTB file."));
+}
+
+GRUB_MOD_FINI (fdt)
+{
+  grub_unregister_command (cmd_devicetree);
+}