Current document about how to boot VxWorks is limited. Add several chapters in README.vxworks to document this.
Signed-off-by: Bin Meng bmeng.cn@gmail.com Reviewed-by: Tom Rini trini@konsulko.com
---
Changes in v2: - Describe typical values for bootaddr, e820data, e820info.
doc/README.vxworks | 82 ++++++++++++++++++++++++++++++++++++++++++++++++------ doc/README.x86 | 2 ++ 2 files changed, 76 insertions(+), 8 deletions(-)
diff --git a/doc/README.vxworks b/doc/README.vxworks index 4cb302e..3433e4f 100644 --- a/doc/README.vxworks +++ b/doc/README.vxworks @@ -1,19 +1,85 @@ -From VxWorks 6.9+ (not include 6.9), VxWorks starts adopting device tree as its hardware -decription mechansim (for PowerPC and ARM), thus requiring boot interface changes. +# +# Copyright (C) 2013, Miao Yan miao.yan@windriver.com +# Copyright (C) 2015, Bin Meng bmeng.cn@gmail.com +# +# SPDX-License-Identifier: GPL-2.0+ +# + +VxWorks Support +=============== + +This document describes the information about U-Boot loading VxWorks kernel. + +Status +------ +U-Boot supports loading VxWorks kernels via 'bootvx' and 'bootm' commands. +For booting old kernels (6.9.x) on PowerPC and ARM, and all kernel versions +on other architectures, 'bootvx' shall be used. For booting VxWorks 7 kernels +on PowerPC and ARM, 'bootm' shall be used. + +64-bit x86 kernel cannot be loaded as of today. + +VxWork 7 on PowerPC and ARM +--------------------------- +From VxWorks 7, VxWorks starts adopting device tree as its hardware decription +mechansim (for PowerPC and ARM), thus requiring boot interface changes. This section will describe the new interface.
-For PowerPC, the calling convention of the new VxWorks entry point conforms to the ePAPR standard, -which is shown below (see ePAPR for more details): +For PowerPC, the calling convention of the new VxWorks entry point conforms to +the ePAPR standard, which is shown below (see ePAPR for more details):
- void (*kernel_entry)(fdt_addr, - 0, 0, EPAPR_MAGIC, boot_IMA, 0, 0) + void (*kernel_entry)(fdt_addr, 0, 0, EPAPR_MAGIC, boot_IMA, 0, 0)
For ARM, the calling convention is show below:
void (*kernel_entry)(void *fdt_addr)
-When booting new VxWorks kernel (uImage format), the parameters passed to bootm is like below: +When booting new VxWorks kernel (uImage format), the parameters passed to bootm +is like below:
bootm <kernel image address> - <device tree address>
-The do_bootvx command still works as it was for older VxWorks kernels. +VxWorks bootline +---------------- +When using 'bootvx', the kernel bootline must be prepared by U-Boot at a +board-specific address before loading VxWorks. U-Boot supplies its address +via "bootaddr" environment variable. To check where the bootline should be +for a specific board, go to the VxWorks BSP for that board, and look for a +parameter called BOOT_LINE_ADRS. Assign its value to "bootaddr". A typical +value for "bootaddr" is 0x101200. + +If a "bootargs" variable is defined, its content will be copied to the memory +location pointed by "bootaddr" as the kernel bootline. If "bootargs" is not +there, command 'bootvx' can construct a valid bootline using the following +environments variables: bootdev, bootfile, ipaddr, netmask, serverip, +gatewayip, hostname, othbootargs. + +When using 'bootm', just define "bootargs" in the environment and U-Boot will +handle bootline fix up for the kernel dtb automatically. + +Serial console +-------------- +It's very common that VxWorks BSPs configure a different baud rate for the +serial console from what is being used by U-Boot. For example, VxWorks tends +to use 9600 as the default baud rate on all x86 BSPs while U-Boot uses 115200. +Please configure both U-Boot and VxWorks to use the same baud rate, or it may +look like VxWorks hangs somewhere as nothing outputs on the serial console. + +x86-specific information +------------------------ +Before loading an x86 kernel, two additional environment variables need to be +provided. They are "e820data" and "e820info", which represent the address of +E820 table and E820 information (defined by VxWorks) in system memory. + +Check VxWorks kernel configuration to look for BIOS_E820_DATA_START and +BIOS_E820_INFO_START, and assign their values to "e820data" and "e820info" +accordingly. If neither of these two are supplied, U-Boot assumes a default +location at 0x4000 for "e820data" and 0x4a00 for "e820info". Typical values +for "e820data" and "e820info" are 0x104000 and 0x104a00. But there is one +exception on Intel Galileo, where "e820data" and "e820info" should be left +unset, which assume the default location for VxWorks. + +Note since currently U-Boot does not support ACPI yet, VxWorks kernel must +be configured to use MP table and virtual wire interrupt mode. This requires +INCLUDE_MPTABLE_BOOT_OP and INCLUDE_VIRTUAL_WIRE_MODE to be included in a +VxWorks kernel configuration. diff --git a/doc/README.x86 b/doc/README.x86 index 6cf293b..a4f5321 100644 --- a/doc/README.x86 +++ b/doc/README.x86 @@ -25,6 +25,8 @@ targets and all Intel boards support running U-Boot 'bare metal'.
As for loading an OS, U-Boot supports directly booting a 32-bit or 64-bit Linux kernel as part of a FIT image. It also supports a compressed zImage. +U-Boot supports loading an x86 VxWorks kernel. Please check README.vxworks +for more details.
Build Instructions for U-Boot as coreboot payload -------------------------------------------------