Re: [RFC PATCH] ARM: OMAP4: ID: Improve features detection and check

[ivan.khoronzhuk]

On 11/01/2012 01:35 PM, Santosh Shilimkar wrote:
> On Thursday 01 November 2012 03:53 PM, Ivan Khoronzhuk wrote:
> > Replaces several flags bearing the same meaning. There is no need
> > to set flags due to different omap types here, it can be checked
> > in appropriate places as well.
> >
> > Cc: Tony Lindgren <tony@xxxxxxxxxxx>
> > Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
> > Cc: linux-omap@xxxxxxxxxxxxxxx
> > Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> > Cc: linux-kernel@xxxxxxxxxxxxxxx
> > Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@xxxxxx>
> > ---
> >   arch/arm/mach-omap2/id.c  |   25 +++++++------------------
> >   arch/arm/mach-omap2/soc.h |    8 ++------
> >   2 files changed, 9 insertions(+), 24 deletions(-)
> >
> > diff --git a/arch/arm/mach-omap2/id.c b/arch/arm/mach-omap2/id.c
> > index cf2362c..3c47a19 100644
> > --- a/arch/arm/mach-omap2/id.c
> > +++ b/arch/arm/mach-omap2/id.c
> > @@ -28,6 +28,9 @@
> >   #include "soc.h"
> >   #include "control.h"
> >
> > +#define OMAP4_SILICON_TYPE_STANDARD        0x01
> > +#define OMAP4_SILICON_TYPE_PERFORMANCE        0x02
> > +
> >   static unsigned int omap_revision;
> >   static const char *cpu_rev;
> >   u32 omap_features;
> > @@ -273,25 +276,11 @@ void __init omap4xxx_check_features(void)
> >   {
> >       u32 si_type;
> >
> > -    if (cpu_is_omap443x())
> > -        omap_features |= OMAP4_HAS_MPU_1GHZ;
> > -
> > +    si_type =
> > +    (read_tap_reg(OMAP4_CTRL_MODULE_CORE_STD_FUSE_PROD_ID_1) >> 16) 
> > & 0x03;
> >
> > -    if (cpu_is_omap446x()) {
> > -        si_type =
> > - read_tap_reg(OMAP4_CTRL_MODULE_CORE_STD_FUSE_PROD_ID_1);
> > -        switch ((si_type & (3 << 16)) >> 16) {
> > -        case 2:
> > -            /* High performance device */
> > -            omap_features |= OMAP4_HAS_MPU_1_5GHZ;
> > -            break;
> > -        case 1:
> > -        default:
> > -            /* Standard device */
> > -            omap_features |= OMAP4_HAS_MPU_1_2GHZ;
> > -            break;
> > -        }
> > -    }
> > +    if (si_type == OMAP4_SILICON_TYPE_PERFORMANCE)
> > +        omap_features = OMAP4_HAS_PERF_SILICON;
>
> Well the detection isn't for performance/standard but there are some
> features depend on it. For example 1 GHz doesn't DPLL DCC enable feature
> where as 1.2 GHz, 1.5 GHz doesn't need. This is the main reason this
> information is also effused. Have you considered this aspect while
> creating this patch ?
>
> Regards
> Santosh

I had considered it. There is no dependency on the features.
DCC usage depends on asked frequency on the fly, not from the features.
Depending on "performance/standard" feature the available frequencies
should be chosen in places where they are needed, for example while
initializing OPPs.

Currently we have several features while it is only one indeed.


--
Regards,
Ivan Khoronzhuk

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