[U-Boot] [PATCH] am33xx, spl, siemens: enable debug uart output again

[Tom Rini <trini@konsulko.com>]

On Wed, Mar 04, 2015 at 08:42:58AM +0100, Heiko Schocher wrote:
> Hello Tom,
> 
> Am 02.03.2015 14:59, schrieb Tom Rini:
> >On Mon, Mar 02, 2015 at 07:56:41AM +0100, Heiko Schocher wrote:
> >>Hello Simon,
> >>
> >>Am 24.02.2015 14:31, schrieb Simon Glass:
> >>>Hi Heiko,
> >>>
> >>>On 23 February 2015 at 23:18, Heiko Schocher <hs@denx.de> wrote:
> >>>>a6b541b090: TI ARMv7: Don't use GD before crt0.S has set it
> >>>>
> >>>>moves the init of the debug uart at the very end of SPL code.
> >>>>Enable it for the siemens board earlier, as they print
> >>>>ddr settings ... all debug output before board_init_r()
> >>>>is here currently useless. Maybe we must rework this
> >>>>globally?
> >>>
> >>>Assuming we are talking about U-Boot proper, the DDR init should
> >>>happen in board_init_f(), specifically dram_init(). so I think this
> >>>code should be updated.
> >>>
> >>>If it is SPL, then DDR init should happen in SPL's board_init_f().
> >>
> >>It is in SPL...
> >>
> >>sdram_init() is called from:
> >>
> >>./arch/arm/cpu/armv7/am33xx/board.c from s_init() ...
> >>
> >>>I sent a series a few weeks ago (available at u-boot-dm branch
> >>>spl-working) related to this topic:
> >>>
> >>>http://patchwork.ozlabs.org/patch/438581/
> >>
> >>Ah ... Hmm... so "./arch/arm/cpu/armv7/am33xx/board.c" needs
> >>a rework, right?
> >>
> >>Is a simple rename s_init() -> board_init_f() correct?
> >
> >Right so, no, we can't just rename s_init to board_init_f.  This is what
> >I was talking about in the thread about the function Hans wants to add
> >to enable some bits in CP15 on sunxi, iirc.
> >
> >In short, armv7 has a different set of abstraction hooks than the
> >previous ARM cores (armv8 followed what we have for v7) and I'm not
> >convinced in the end that it really won us anything.  See
> >http://lists.denx.de/pipermail/u-boot/2015-January/202350.html
> >
> >For today you need to rework the Siemens code to print out the DDR
> >values (when desired) in spl_board_init() as we do not, or will not
> >shortly, have gd prior to board_init_f running.
> 
> Hmm... first I thought, ok, no problem, move the output from the RAM
> parameters to spl_board_init() ... but thats only the half of the
> story ... They read the RAM parameters from an i2c eeprom, and if
> there are errors, they print this errors ... currently this does
> not work, and thats I think the more important case ... and I could
> not move this error printfs to somewhere, because if RAM is not
> working ... there is no later ...
> 
> So I have to enable the console early ... maybe I missed something,
> but this worked fine in the past (and I think we should not break
> this, as this is an essential feature).

OK, I missed something too.  I think this gets better now once I merge
Simon's SPL series as we do all of this from board_init_f() and the
siemens code should just work again.

> If I look into arch/arm/cpu/armv7/am33xx/board.c s_init()
> there gets the console also in the case:
> 
> #if defined(CONFIG_NOR_BOOT) || defined(CONFIG_QSPI_BOOT)
> 
> very early enabled ... is this buggy?

Digging out one of the QSPI bootable boards (which I only _think_ I
have) or setting up and confirming the beaglebone white + NOR cape I
have still functions at the HW level and then re-testing on mainline are
on my list as yes, I'm a bit worried these paths might be broken again.

-- 
Tom
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