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When U-Boot started using SPDX tags we were among the early adopters and there weren't a lot of other examples to borrow from. So we picked the area of the file that usually had a full license text and replaced it with an appropriate SPDX-License-Identifier: entry. Since then, the Linux Kernel has adopted SPDX tags and they place it as the very first line in a file (except where shebangs are used, then it's second line) and with slightly different comment styles than us. In part due to community overlap, in part due to better tag visibility and in part for other minor reasons, switch over to that style. This commit changes all instances where we have a single declared license in the tag as both the before and after are identical in tag contents. There's also a few places where I found we did not have a tag and have introduced one. Signed-off-by: Tom Rini <trini@konsulko.com>
97 lines
4.2 KiB
Plaintext
97 lines
4.2 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0+
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#
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# Copyright (C) 2013, Miao Yan <miao.yan@windriver.com>
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# Copyright (C) 2015, Bin Meng <bmeng.cn@gmail.com>
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VxWorks Support
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===============
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This document describes the information about U-Boot loading VxWorks kernel.
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Status
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------
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U-Boot supports loading VxWorks kernels via 'bootvx' and 'bootm' commands.
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For booting old kernels (6.9.x) on PowerPC and ARM, and all kernel versions
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on other architectures, 'bootvx' shall be used. For booting VxWorks 7 kernels
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on PowerPC and ARM, 'bootm' shall be used.
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VxWorks 7 on PowerPC and ARM
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---------------------------
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From VxWorks 7, VxWorks starts adopting device tree as its hardware decription
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mechansim (for PowerPC and ARM), thus requiring boot interface changes.
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This section will describe the new interface.
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For PowerPC, the calling convention of the new VxWorks entry point conforms to
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the ePAPR standard, which is shown below (see ePAPR for more details):
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void (*kernel_entry)(fdt_addr, 0, 0, EPAPR_MAGIC, boot_IMA, 0, 0)
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For ARM, the calling convention is shown below:
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void (*kernel_entry)(void *fdt_addr)
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When booting a VxWorks 7 kernel (uImage format), the parameters passed to bootm
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is like below:
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bootm <kernel image address> - <device tree address>
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VxWorks bootline
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----------------
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When using 'bootvx', the kernel bootline must be prepared by U-Boot at a
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board-specific address before loading VxWorks. U-Boot supplies its address
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via "bootaddr" environment variable. To check where the bootline should be
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for a specific board, go to the VxWorks BSP for that board, and look for a
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parameter called BOOT_LINE_ADRS. Assign its value to "bootaddr". A typical
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value for "bootaddr" on an x86 board is 0x101200.
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If a "bootargs" variable is defined, its content will be copied to the memory
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location pointed by "bootaddr" as the kernel bootline. If "bootargs" is not
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there, command 'bootvx' can construct a valid bootline using the following
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environments variables: bootdev, bootfile, ipaddr, netmask, serverip,
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gatewayip, hostname, othbootargs.
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When using 'bootm', just define "bootargs" in the environment and U-Boot will
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handle bootline fix up for the kernel dtb automatically.
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Serial console
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--------------
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It's very common that VxWorks BSPs configure a different baud rate for the
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serial console from what is being used by U-Boot. For example, VxWorks tends
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to use 9600 as the default baud rate on all x86 BSPs while U-Boot uses 115200.
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Please configure both U-Boot and VxWorks to use the same baud rate, or it may
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look like VxWorks hangs somewhere as nothing outputs on the serial console.
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x86-specific information
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------------------------
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Before loading an x86 kernel, one additional environment variable need to be
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provided. This is "vx_phys_mem_base", which represent the physical memory
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base address of VxWorks.
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Check VxWorks kernel configuration to look for LOCAL_MEM_LOCAL_ADRS. For
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VxWorks 7, this is normally a virtual address and you need find out its
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corresponding physical address and assign its value to "vx_phys_mem_base".
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For boards on which ACPI is not supported by U-Boot yet, VxWorks kernel must
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be configured to use MP table and virtual wire interrupt mode. This requires
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INCLUDE_MPTABLE_BOOT_OP and INCLUDE_VIRTUAL_WIRE_MODE to be included in a
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VxWorks kernel configuration.
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Both 32-bit x86 and 64-bit x64 kernels can be loaded.
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There are two types of graphics console drivers in VxWorks. One is the 80x25
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VGA text mode driver. The other one is the EFI console bitmapped graphics mode
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driver. To make these drivers function, U-Boot needs to load and run the VGA
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BIOS of the graphics card first.
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- If the kernel is configured with 80x25 VGA text mode driver,
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CONFIG_FRAMEBUFFER_SET_VESA_MODE must be unset in U-Boot.
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- If the kernel is configured with bitmapped graphics mode driver,
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CONFIG_FRAMEBUFFER_SET_VESA_MODE need remain set but care must be taken
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at which VESA mode is to be set. The supported pixel format is 32-bit
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RGBA, hence the available VESA mode can only be one of the following:
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* FRAMEBUFFER_VESA_MODE_10F
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* FRAMEBUFFER_VESA_MODE_112
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* FRAMEBUFFER_VESA_MODE_115
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* FRAMEBUFFER_VESA_MODE_118
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* FRAMEBUFFER_VESA_MODE_11B
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