[U-Boot] [PATCH v2] arm: omap: Fix 'get_device_type()' for OMAP34XX

[Tom Rini]

On Thu, Aug 10, 2017 at 07:25:29AM -0500, Derald Woods wrote:

> On Mon, Aug 7, 2017 at 5:19 PM, Derald Woods <woods.technical at gmail.com>
> wrote:
> 
> > On Mon, Aug 7, 2017 at 7:41 AM, Tom Rini <trini at konsulko.com> wrote:
> >
> >> On Mon, Aug 07, 2017 at 07:35:30AM -0500, Derald Woods wrote:
> >> > On Mon, Jul 31, 2017 at 7:41 AM, Derald D. Woods <
> >> woods.technical at gmail.com>
> >> > wrote:
> >> >
> >> > > Fixes: 00bbe96ebabb ("arm: omap: Unify get_device_type() function")
> >> > >
> >> > > The control status register value is embedded in a structure somewhere
> >> > > in SRAM, with the last refactoring effort. This patch allows OMAP3 EVM
> >> > > (TMDSEVM3530) to boot again using the known control register base and
> >> > > offset for 'readl', for the OMAP34XX case.
> >> > >
> >> > > Signed-off-by: Derald D. Woods <woods.technical at gmail.com>
> >> > >
> >> > > ---
> >> > > Changes in v2:
> >> > > - Added 'signed-off-by'
> >> > > - Updated description
> >> > >
> >> > > ---
> >> > >  arch/arm/mach-omap2/sysinfo-common.c | 4 ++++
> >> > >  1 file changed, 4 insertions(+)
> >> > >
> >> > > diff --git a/arch/arm/mach-omap2/sysinfo-common.c
> >> > > b/arch/arm/mach-omap2/sysinfo-common.c
> >> > > index 1dc7051ab3..3955e803ad 100644
> >> > > --- a/arch/arm/mach-omap2/sysinfo-common.c
> >> > > +++ b/arch/arm/mach-omap2/sysinfo-common.c
> >> > > @@ -16,6 +16,10 @@
> >> > >   */
> >> > >  u32 get_device_type(void)
> >> > >  {
> >> > > +#if defined(CONFIG_OMAP34XX)
> >> > > +       return (readl(OMAP34XX_CTRL_BASE + 0x2f0) & DEVICE_TYPE_MASK)
> >> >>
> >> > > +               DEVICE_TYPE_SHIFT;
> >> > > +#endif
> >> > >         return (readl((*ctrl)->control_status) & DEVICE_TYPE_MASK) >>
> >> > >                 DEVICE_TYPE_SHIFT;
> >> > >  }
> >> >
> >> > ​Is there any​ comment or concern with this patch? It was the simplest
> >> > means to get OMAP35XX booting again and still keep the original patch.
> >> > Basically it avoids the pointer to the OMAP_SRAM_SCRATCH_SYS_CTRL
> >> located
> >> > structure as now defined in "arch/arm/mach-omap2/omap3/hw_data.c".
> >> OMAP3
> >> > has a larger active SOC base than just OMAP36XX and greater. Was there
> >> > anything really broken with 'get_device_type()' previously?
> >>
> >> Is the pointer value wrong for 35xx?  The problem, such as it was, was
> >> having the same function duplicated in a number of places, and needing
> >> to make it more easily / readily available (rather than duplicated
> >> again) for some additional patches.  I'd really rather not introduce
> >> an #if here unless we really have no other choice.  Thanks!
> >>
> >> --
> >> Tom
> >>
> >
> > ​I will examine/debug the new 'get_device_type()' source code again
> > tonight. ‎Without the patch, I have two OMAP3530 boards that do not boot at
> > all.
> >
> ​​
> 
> Derald​
> ​
> 
> In "arch/arm/mach-omap2/omap3/board.c", the following routines call
> 'get_device_type':
> - v7_arch_cp15_set_l2aux_ctrl      (called from
> "arch/arm/cpu/armv7/start.S")
> - v7_arch_cp15_set_acr             (called from
> "arch/arm/cpu/armv7/start.S")
> - omap3_invalidate_l2_cache_secure (called from "board.c" 's_init')
> - try_unlock_memory                (called from "board.c" 's_init')
> 
> Each one of these calls to 'get_device_type' seems to have a purpose (i.e.
> ERRATA or setup). What it highlights is the difference in usage from
> OMAP36XX, AM33XX, and newer. The SRAM usage, L2 cache and call ordering are
> likely factors here. ​Figuring out the implications for OMAP34XX will take
> time. But you need to have boards that boot to address those issues. So
> 'get_device_type' usage, for OMAP34XX, is not strictly a "Apples to Apples"
> type comparison. For now I can proceed with an "out-of-tree" patch, since
> it is small. Let me know if there is something that I am missing here.

OK, thanks for the analysis.  It is indeed a bit too much overhead atm
to see if we can further reconcile all of the code and should grab your
patch, thanks!

-- 
Tom
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