Hi Graeme,
On Tue, Mar 20, 2012 at 5:39 PM, Graeme Russ graeme.russ@gmail.com wrote:
Hi Simon
On Wed, Mar 21, 2012 at 11:19 AM, Simon Glass sjg@chromium.org wrote:
Hi Graeme,
On Tue, Mar 20, 2012 at 5:17 PM, Graeme Russ graeme.russ@gmail.com wrote:
Hi Simon,
And we are talking about one board vendor taking a SoC and using UARTA for the panic output and another board vendor deciding to use UARTB - But surely these vendors will create a separate config file for their boards.
Nope. There is only one u-boot.bin for all boards that use this SOC.
And this is what I simply don't grok - Why have a single board config for a range of boards that are obviously different?
That's the design goal - a single U-Boot binary for all boards that use a particular SOC.
I suppose I haven't dealt with device tree and I imagine that is what this is all about. But to me, device trees are a construct for a higher level of operation (the OS) not the boot loader (although I get that the boot loader can parse the device tree in order to pick up what devices are installed and need some kind of low-level initialisation)
Actually a device tree describes the hardware, and therefore should in principle be just as applicable to the boot loader.
I think at such a low level you really have to say 'hey, these boards are different and need a different configuration' unless you put something in hardware that allows U-Boot to pick up on the difference without needing to initialise _anything_ similar to what Stephen has done to pass the debug UART info to Linux via a scratch register
Well we could do that, but the config is in some sense supposed to be the device tree. We are only dealing here with a little case where there is no device tree and want to output a message.
Regards, Simon
Regards,
Graeme