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+# Copyright (c) 2016 Google, Inc
+# Written by Simon Glass <sjg@chromium.org>
+#
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Entry-type module for a U-Boot binary with an embedded microcode pointer
+#
+
+from entry import Entry
+from blob import Entry_blob
+import tools
+
+class Entry_u_boot_ucode(Entry_blob):
+ """U-Boot microcode block
+
+ U-Boot on x86 needs a single block of microcode. This is collected from
+ the various microcode update nodes in the device tree. It is also unable
+ to read the microcode from the device tree on platforms that use FSP
+ (Firmware Support Package) binaries, because the API requires that the
+ microcode is supplied before there is any SRAM available to use (i.e.
+ the FSP sets up the SRAM / cache-as-RAM but does so in the call that
+ requires the microcode!). To keep things simple, all x86 platforms handle
+ microcode the same way in U-Boot (even non-FSP platforms). This is that
+ a table is placed at _dt_ucode_base_size containing the base address and
+ size of the microcode. This is either passed to the FSP (for FSP
+ platforms), or used to set up the microcode (for non-FSP platforms).
+ This all happens in the build system since it is the only way to get
+ the microcode into a single blob and accessible without SRAM.
+
+ There are two cases to handle. If there is only one microcode blob in
+ the device tree, then the ucode pointer it set to point to that. This
+ entry (u-boot-ucode) is empty. If there is more than one update, then
+ this entry holds the concatenation of all updates, and the device tree
+ entry (u-boot-dtb-with-ucode) is updated to remove the microcode. This
+ last step ensures that that the microcode appears in one contiguous
+ block in the image and is not unnecessarily duplicated in the device
+ tree. It is referred to as 'collation' here.
+
+ Entry types that have a part to play in handling microcode:
+
+ Entry_u_boot_with_ucode_ptr:
+ Contains u-boot-nodtb.bin (i.e. U-Boot without the device tree).
+ It updates it with the address and size of the microcode so that
+ U-Boot can find it early on start-up.
+ Entry_u_boot_dtb_with_ucode:
+ Contains u-boot.dtb. It stores the microcode in a
+ 'self.ucode_data' property, which is then read by this class to
+ obtain the microcode if needed. If collation is performed, it
+ removes the microcode from the device tree.
+ Entry_u_boot_ucode:
+ This class. If collation is enabled it reads the microcode from
+ the Entry_u_boot_dtb_with_ucode entry, and uses it as the
+ contents of this entry.
+ """
+ def __init__(self, image, etype, node):
+ Entry_blob.__init__(self, image, etype, node)
+
+ def ObtainContents(self):
+ # If the image does not need microcode, there is nothing to do
+ ucode_dest_entry = self.image.FindEntryType('u-boot-with-ucode-ptr')
+ if ucode_dest_entry and not ucode_dest_entry.target_pos:
+ self.data = ''
+ return True
+
+ # Get the microcode from the device tree entry
+ fdt_entry = self.image.FindEntryType('u-boot-dtb-with-ucode')
+ if not fdt_entry or not fdt_entry.ucode_data:
+ return False
+
+ if not fdt_entry.collate:
+ # This section can be empty
+ self.data = ''
+ return True
+
+ # Write it out to a file
+ dtb_name = 'u-boot-ucode.bin'
+ fname = tools.GetOutputFilename(dtb_name)
+ with open(fname, 'wb') as fd:
+ fd.write(fdt_entry.ucode_data)
+
+ self._pathname = fname
+ self.ReadContents()
+
+ return True