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Diffstat (limited to 'tools/binman/etype/u_boot_ucode.py')
-rw-r--r-- | tools/binman/etype/u_boot_ucode.py | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/tools/binman/etype/u_boot_ucode.py b/tools/binman/etype/u_boot_ucode.py new file mode 100644 index 00000000000..8fe27acb245 --- /dev/null +++ b/tools/binman/etype/u_boot_ucode.py @@ -0,0 +1,84 @@ +# 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 |