On 26/12/2012 19:23, Otavio Salvador wrote:
> On Wed, Dec 26, 2012 at 10:14 AM, Fabio Estevam <feste...@gmail.com> wrote:
>> On Wed, Dec 26, 2012 at 9:31 AM, Stefano Babic <sba...@denx.de> wrote:
>>
>>> Only to remark that this is the correct behavior. The kernel with fdt is
>>> booted independently if this is wanted or not, but if the fdt file is
>>> loaded successfully from MMC or network. This can have some drawback
>>> effects if, for example, the fdt is simply stored on the TFTP server,
>>> but we want to boot a kernel without DT. For example, when someone wants
>>> to test both kernels or there are multiple instances of the same board
>>> type (mx53loco in this case) loading from the same TFTP server.
>>>
>>> In your patch, the behavior depends if the fdt is simply present on the
>>> media, but this does not always mean that the file must be loaded.
>>> Should be not better to set variable as flag to force the desired
>>> behavior and to be sure that the system does not boot in a different way
>>> as the user thinks ?
>>>
>>> In other words, something like :
>>>
>>> "if boot_fdt; then " \
>>> "if dhcp ${ftd_addr} ${ftd_file}; then " \
>>> "bootm ${loadaddr} - ${ftd_addr}; " \
>>> "else " \
>>> "echo Error: I cannot boot a DT kernel; \"
>>> "fi; \"
>>> " else bootm; fi;\0"
>>
>>
>> Yes, I think this is a good idea and would allow us to easily switch
>> from dt to non-dt kernel during tests.
>
> I like the idea but maybe we could have three states?
>
> boot_fdt=yes
>
> It'd imply force fdt and would behave as you said above;
>
> boot_fdt=no
>
> Would ignore the fdt completely
>
> boot_fdt=auto
>
> The current code, which try to load fdt and do not fail otherwise.
>
> Comments?
Reading again your environment, it seems to me that you strictly bind
the network configuration with fdt. But they are two distinct setup.
Let's say, if I desire to start a fdt kernel but I have a static ip
address. In this case, I should load with "tftp" instead using "dhcp".
So the necessity to have a three state is due to the fact you are
setting more as one state in one shot: fdt or not, and dhcp or not. IMHO
you need two variables to manage them independently. I think I did
something like this in another board, but I do not remember which one ;-(.
So you can have:
boot_fdt
ip_dyn
to discriminate what the script should do.
"if boot_fdt; then " \
"if ip_dyn;then" \
"if dhcp ${ftd_addr} ${ftd_file}; then " \
"bootm ${loadaddr} - ${ftd_addr}; " \
"else " \
"echo Error: I cannot boot a DT kernel; \"
"fi;" \
"else tftp ${ftd_addr} ${ftd_file}
.....
Regards,
Stefano
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