1# SPDX-License-Identifier: GPL-2.0+ 2# 3# Copyright (C) 2013, Miao Yan <miao.yan@windriver.com> 4# Copyright (C) 2015, Bin Meng <bmeng.cn@gmail.com> 5 6VxWorks Support 7=============== 8 9This document describes the information about U-Boot loading VxWorks kernel. 10 11Status 12------ 13U-Boot supports loading VxWorks kernels via 'bootvx' and 'bootm' commands. 14For booting old kernels (6.9.x) on PowerPC and ARM, and all kernel versions 15on other architectures, 'bootvx' shall be used. For booting VxWorks 7 kernels 16on PowerPC and ARM, 'bootm' shall be used. 17 18VxWorks 7 on PowerPC and ARM 19--------------------------- 20From VxWorks 7, VxWorks starts adopting device tree as its hardware decription 21mechansim (for PowerPC and ARM), thus requiring boot interface changes. 22This section will describe the new interface. 23 24For PowerPC, the calling convention of the new VxWorks entry point conforms to 25the ePAPR standard, which is shown below (see ePAPR for more details): 26 27 void (*kernel_entry)(fdt_addr, 0, 0, EPAPR_MAGIC, boot_IMA, 0, 0) 28 29For ARM, the calling convention is shown below: 30 31 void (*kernel_entry)(void *fdt_addr) 32 33When booting a VxWorks 7 kernel (uImage format), the parameters passed to bootm 34is like below: 35 36 bootm <kernel image address> - <device tree address> 37 38VxWorks bootline 39---------------- 40When using 'bootvx', the kernel bootline must be prepared by U-Boot at a 41board-specific address before loading VxWorks. U-Boot supplies its address 42via "bootaddr" environment variable. To check where the bootline should be 43for a specific board, go to the VxWorks BSP for that board, and look for a 44parameter called BOOT_LINE_ADRS. Assign its value to "bootaddr". A typical 45value for "bootaddr" on an x86 board is 0x101200. 46 47If a "bootargs" variable is defined, its content will be copied to the memory 48location pointed by "bootaddr" as the kernel bootline. If "bootargs" is not 49there, command 'bootvx' can construct a valid bootline using the following 50environments variables: bootdev, bootfile, ipaddr, netmask, serverip, 51gatewayip, hostname, othbootargs. 52 53When using 'bootm', just define "bootargs" in the environment and U-Boot will 54handle bootline fix up for the kernel dtb automatically. 55 56Serial console 57-------------- 58It's very common that VxWorks BSPs configure a different baud rate for the 59serial console from what is being used by U-Boot. For example, VxWorks tends 60to use 9600 as the default baud rate on all x86 BSPs while U-Boot uses 115200. 61Please configure both U-Boot and VxWorks to use the same baud rate, or it may 62look like VxWorks hangs somewhere as nothing outputs on the serial console. 63 64x86-specific information 65------------------------ 66Before loading an x86 kernel, one additional environment variable need to be 67provided. This is "vx_phys_mem_base", which represent the physical memory 68base address of VxWorks. 69 70Check VxWorks kernel configuration to look for LOCAL_MEM_LOCAL_ADRS. For 71VxWorks 7, this is normally a virtual address and you need find out its 72corresponding physical address and assign its value to "vx_phys_mem_base". 73 74For boards on which ACPI is not supported by U-Boot yet, VxWorks kernel must 75be configured to use MP table and virtual wire interrupt mode. This requires 76INCLUDE_MPTABLE_BOOT_OP and INCLUDE_VIRTUAL_WIRE_MODE to be included in a 77VxWorks kernel configuration. 78 79Both 32-bit x86 and 64-bit x64 kernels can be loaded. 80 81There are two types of graphics console drivers in VxWorks. One is the 80x25 82VGA text mode driver. The other one is the EFI console bitmapped graphics mode 83driver. To make these drivers function, U-Boot needs to load and run the VGA 84BIOS of the graphics card first. 85 86 - If the kernel is configured with 80x25 VGA text mode driver, 87 CONFIG_FRAMEBUFFER_SET_VESA_MODE must be unset in U-Boot. 88 - If the kernel is configured with bitmapped graphics mode driver, 89 CONFIG_FRAMEBUFFER_SET_VESA_MODE need remain set but care must be taken 90 at which VESA mode is to be set. The supported pixel format is 32-bit 91 RGBA, hence the available VESA mode can only be one of the following: 92 * FRAMEBUFFER_VESA_MODE_10F 93 * FRAMEBUFFER_VESA_MODE_112 94 * FRAMEBUFFER_VESA_MODE_115 95 * FRAMEBUFFER_VESA_MODE_118 96 * FRAMEBUFFER_VESA_MODE_11B 97