[U-Boot] [RFC PATCH 1/3] add file with a default boot environment based heavily on Stephen Warrens recent tegra work.

[Dan Murphy]

On 02/19/2014 01:16 PM, Tom Rini wrote:
> On Wed, Feb 19, 2014 at 01:05:15PM -0600, Dan Murphy wrote:
>> On 02/19/2014 01:02 PM, Eric Nelson wrote:
>>> On 02/19/2014 11:57 AM, Stephen Warren wrote:
>>>> On 02/19/2014 11:52 AM, Dan Murphy wrote:
>>>>> On 02/19/2014 12:48 PM, Stephen Warren wrote:
>>>>>> On 02/19/2014 11:44 AM, Dan Murphy wrote:
>>>>>>> On 02/17/2014 11:56 AM, Dennis Gilmore wrote:
>>>>>>>> Signed-off-by: Dennis Gilmore <dennis at ausil.us>
>>>>>>>> diff --git a/include/config_distro_bootcmd.h b/include/config_distro_bootcmd.h
>>>>>>>> +#ifdef CONFIG_CMD_USB
>>>>>>>> +#define BOOTCMD_INIT_USB "run usb_init; "
>>>>>>>> +#define BOOTCMDS_USB \
>>>>>>>> +    "usb_init=" \
>>>>>>>> +        "if ${usb_need_init}; then " \
>>>>>>>> +            "set usb_need_init false; " \
>>>>>>>> +            "usb start 0; " \
>>>>>>>> +        "fi\0" \
>>>>>>>> +    \
>>>>>>>> +    "usb_boot=" \
>>>>>>>> +        "setenv devtype usb; " \
>>>>>>>> +        BOOTCMD_INIT_USB \
>>>>>>>> +        "if usb dev ${devnum}; then " \
>>>>>>> This may have already been highlighted but I don't see where the kernel command line arguments can be set.
>>>>>>> If you have the file system on the USB stick won't you need to direct the root to the stick?
>>>>>> They would be set in boot.scr or extlinux.cfg on the disk that the
>>>>>> system boots from; the kernel cmdline is part of the OS that's installed
>>>>>> there, not part of U-Boot. This is why these boot scripts load a
>>>>>> script/config-file from the disk which in turn defines which
>>>>>> kernel/DTB/cmdline to use, rather than directly loading a kernel and
>>>>>> DTB. This approach should even be suitable for booting a non-Linux-OS,
>>>>>> with suitable commands in boot.scr.
>>>>> But shouldn't the config file just be an override?
>>>>>
>>>>> I don't know if we should be having to need to load a boot.scr or any config file just to get the kernel to boot.
>>>>>
>>>>> If no config file exists should we not try to default to a known good default tested case?
>>>> I believe always loading a script/config-file is the simplest and most
>>>> flexible approach, for a *distro* *oriented* boot process.
>>> +1
>>>
>>> Scripts have the benefit of putting everything into a relatively
>>> easy-to-read form that only uses documented U-Boot commands, not
>>> board-specific constructs.
>>>
>> Oh don't get me wrong I agree with having the scripts.
>>
>> Just sayin we should not rely on the scripts being there and mandating
>> their usage.
>> We may want to have a fall back to a known good tested configuration.
> I think I see where you're coming from, but it's already expected that
> you're passing in a good device tree too, so it would be making sure
> that you also have a useful env file to get loaded in the DHCP or PXE
> case.
>

Do we have a directory where default scripts exist for each board?  Or at least samples for each board?

I could not find them.  If they don't exist then we should probably put them in the board dirs and cp them to the respective out directory

Maybe this would be something that helps defined the known good config that the community can base their changes on.

Dan

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Dan Murphy