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