[U-Boot] [PATCH v3] arm: socfpga: fix issue with warm reset when CSEL is 0

[Dalon Westergreen]

On Mon, 2017-02-20 at 15:24 +0100, Marek Vasut wrote:
> On 02/20/2017 03:21 PM, Dalon Westergreen wrote:
> > 
> > On Mon, 2017-02-20 at 15:14 +0100, Marek Vasut wrote:
> > > 
> > > On 02/20/2017 03:10 PM, Dalon Westergreen wrote:
> > > > 
> > > > 
> > > > On Mon, 2017-02-20 at 10:07 +0100, Marek Vasut wrote:
> > > > > 
> > > > > 
> > > > > On 02/18/2017 02:34 AM, Dalon Westergreen wrote:
> > > > > > 
> > > > > > 
> > > > > > 
> > > > > > When CSEL=0x0 the socfpga bootrom does not touch the clock
> > > > > > configuration for the device.  This can lead to a boot failure
> > > > > > on warm resets. This patch disables warm resets when CSEL=0.
> > > > > > This results in the clock and pll configurations being reset
> > > > > > on any reset issued when CSEL=0.
> > > > > > 
> > > > > > Signed-off-by: Dalon Westergreen <dwesterg at gmail.com>
> > > > > 
> > > > > What about my suggestion for V2 about just loading function pointer
> > > > > into
> > > > > the reset jump address register ?
> > > > 
> > > > Frankly, i really dont like relying on the existence of a snippet of
> > > > code in
> > > > the
> > > > onchip ram being untouched to ensure a reboot/reset will occur for this
> > > > csel=0
> > > > case.  i am certain this case is rarely used, and confident that it isnt
> > > > being
> > > > used while trying to preserve sdram contents.
> > > 
> > > Well, you already rely on such snippet, it's SPL. If you corrupt SPL and
> > > do warm reset, your system hangs, I had that multiple times :)
> > 
> > True.  I would argue to just use cold resets but i think arria 10 has more
> > use
> > for the warm reset case.
> 
> OK
> 
> > 
> > > 
> > > > 
> > > > 
> > > > the downside is that the scorecard is reset every boot. so the bootrom
> > > > will
> > > > retry all the spl images again resulting in possibly longer boot times.
> > > 
> > > Is that significant ?
> > 
> > The watchdog timeout is on the order of 1.5 seconds.  That would be for each
> > failed spl.
> 
> Hm, OK. But then your system is kinda broken, so you should expect this
> I guess.

My thought exactly...  I would like to see if Chin Liang or Dinh have any
comments?

> 
> [...]
>