[PATCH 1/4] arm: omap: hwmod: 43xx: add DebugSS hwmod data

[Paul Walmsley]

On Tue, 10 Feb 2015, Felipe Balbi wrote:

> On Tue, Feb 10, 2015 at 11:12:40PM +0000, Paul Walmsley wrote:
> > > > > > > > > hm... modulemode SWCTRL causes wait_target_ready to fail. Any hints ?
> > > > > > > > 
> > > > > > > > gets stuck in transition state. PRCM_CM_WKUP_DBGSS_CLKCTRL is always
> > > > > > > > read as 0x 12510f00 which would translate into:
> > > > > > > > 
> > > > > > > > - module disabled
> > > > > > > > - all opt clocks are on
> > > > > > > > - module is transitioning
> > > > > > > > - module in standby
> > > > > > > > - clkA as TPIU and STM trace clock
> > > > > > > > - all dividers set to 2
> > > > > > > 
> > > > > > > just fyi, checking with HW folks, this might be a new bug, unless
> > > > > > > debugss needs something special.
> > > > > > 
> > > > > > If that happens on DEBUGSS disable, it's probably the same issue as on 
> > > > > > AM33xx:
> > > > > > 
> > > > > > http://www.spinics.net/lists/arm-kernel/msg320801.html
> > > > > > http://www.spinics.net/lists/arm-kernel/msg321930.html
> > > > > > http://www.spinics.net/lists/arm-kernel/msg329151.html
> > > > > > 
> > > > > > Does adding HWMOD_INIT_NO_IDLE fix the issue you're seeing?
> > > > > 
> > > > > I'll try it out in a bit...
> > > > 
> > > > nope, same thing.
> > > > 
> > > > [   27.633235] omap_hwmod: debugss: _wait_target_disable failed
> > > 
> > > OK, looking at the code, this makes sense.  So here's what I'd suggest 
> > > asking the hardware team: is the right approach to:
> > > 
> > > 1. keep the DEBUGSS CLKCTRL MODULEMODE bitfield at 0x2 all the time, even 
> > > when it's not in use or when entering chip low-power states, or
> > > 
> > > 2. program the DEBUGSS CLKCTRL MODULEMODE bitfield to 0x0 when the DEBUGSS 
> > > is not in use or when entering chip low-power states, but ignore the 
> > > DEBUGSS CLKCTRL IDLEST register 
> > > 
> > > We'll need a new hwmod flag either way; the question is whether it should 
> > > be something like HWMOD_CANNOT_DISABLE (case 1), or 
> > > HWMOD_DISABLE_IGNORE_IDLEST (case 2).
> > 
> > Just checking on this.  Heard anything from the hardware team?  If not I'd 
> > say the HWMOD_CANNOT_DISABLE approach is probably the right one for now...
> 
> nothing from HW team yet. Last I heard is that they can reproduce the
> issue, and are now digging through documentation (and maybe RTL, but I'm
> speculating) to see if that should be supported or not.
> 
> From my point of view, however, the thing idles, it just doesn't report
> it.

Ok sounds like the thing to do is to wait until you hear back from them, 
if they are still looking at it.


- Paul