1# Copyright (c) 2016 Google, Inc 2# Written by Simon Glass <sjg@chromium.org> 3# 4# SPDX-License-Identifier: GPL-2.0+ 5# 6# Entry-type module for a U-Boot binary with an embedded microcode pointer 7# 8 9from entry import Entry 10from blob import Entry_blob 11import tools 12 13class Entry_u_boot_ucode(Entry_blob): 14 """U-Boot microcode block 15 16 U-Boot on x86 needs a single block of microcode. This is collected from 17 the various microcode update nodes in the device tree. It is also unable 18 to read the microcode from the device tree on platforms that use FSP 19 (Firmware Support Package) binaries, because the API requires that the 20 microcode is supplied before there is any SRAM available to use (i.e. 21 the FSP sets up the SRAM / cache-as-RAM but does so in the call that 22 requires the microcode!). To keep things simple, all x86 platforms handle 23 microcode the same way in U-Boot (even non-FSP platforms). This is that 24 a table is placed at _dt_ucode_base_size containing the base address and 25 size of the microcode. This is either passed to the FSP (for FSP 26 platforms), or used to set up the microcode (for non-FSP platforms). 27 This all happens in the build system since it is the only way to get 28 the microcode into a single blob and accessible without SRAM. 29 30 There are two cases to handle. If there is only one microcode blob in 31 the device tree, then the ucode pointer it set to point to that. This 32 entry (u-boot-ucode) is empty. If there is more than one update, then 33 this entry holds the concatenation of all updates, and the device tree 34 entry (u-boot-dtb-with-ucode) is updated to remove the microcode. This 35 last step ensures that that the microcode appears in one contiguous 36 block in the image and is not unnecessarily duplicated in the device 37 tree. It is referred to as 'collation' here. 38 39 Entry types that have a part to play in handling microcode: 40 41 Entry_u_boot_with_ucode_ptr: 42 Contains u-boot-nodtb.bin (i.e. U-Boot without the device tree). 43 It updates it with the address and size of the microcode so that 44 U-Boot can find it early on start-up. 45 Entry_u_boot_dtb_with_ucode: 46 Contains u-boot.dtb. It stores the microcode in a 47 'self.ucode_data' property, which is then read by this class to 48 obtain the microcode if needed. If collation is performed, it 49 removes the microcode from the device tree. 50 Entry_u_boot_ucode: 51 This class. If collation is enabled it reads the microcode from 52 the Entry_u_boot_dtb_with_ucode entry, and uses it as the 53 contents of this entry. 54 """ 55 def __init__(self, image, etype, node): 56 Entry_blob.__init__(self, image, etype, node) 57 58 def ObtainContents(self): 59 # If the image does not need microcode, there is nothing to do 60 ucode_dest_entry = self.image.FindEntryType('u-boot-with-ucode-ptr') 61 if ucode_dest_entry and not ucode_dest_entry.target_pos: 62 self.data = '' 63 return True 64 65 # Handle microcode in SPL image as well 66 ucode_dest_entry = self.image.FindEntryType('u-boot-spl-with-ucode-ptr') 67 if ucode_dest_entry and not ucode_dest_entry.target_pos: 68 self.data = '' 69 return True 70 71 # Get the microcode from the device tree entry 72 fdt_entry = self.image.FindEntryType('u-boot-dtb-with-ucode') 73 if not fdt_entry or not fdt_entry.ucode_data: 74 return False 75 76 if not fdt_entry.collate: 77 # This section can be empty 78 self.data = '' 79 return True 80 81 # Write it out to a file 82 dtb_name = 'u-boot-ucode.bin' 83 fname = tools.GetOutputFilename(dtb_name) 84 with open(fname, 'wb') as fd: 85 fd.write(fdt_entry.ucode_data) 86 87 self._pathname = fname 88 self.ReadContents() 89 90 return True 91