Re: [RFC] OMAP3 : PM : Handle variable length OPP tables

[Kevin Hilman <khilman@deeprootsystems.com>]

"Premi, Sanjeev" <premi@ti.com> writes:

> Hi all,
>
> There is no generic function to translate an OPP to FREQ and vice versa.
> Came across the problem while trying to submit a follow-up to earlier
> patch for change in mpurate via bootargs. 
>
> The function get_opp in resource34xx.c, but it is always called with an
> explicit addition of MAX_VDDn_OPP e.g.
>
>   opp = get_opp(mpu_opps + MAX_VDD1_OPP, clk->rate);
>   opp = get_opp(l3_opps + MAX_VDD2_OPP, clk->rate);
>
> This is 'addition' is required as there is no encapsulation of the
> MIN and MAX VDDs associated to the table.
>
> The patch below fixes this issue; buy creating a 'table' object with
> necessary information. It can also help in getting rid of the
> empty {0, 0, 0} at index 0 of each OPP table.
>
> At the moment, it does not break any functionality in resource34xx.c;
> migration to this encapsulation can be taken as next step.
>
> This code is bare 'git-diff' for early comments. Formal patch to follow...

Looks ok.  Please send updated patch against current PM branch.

Thanks,

Kevin

> Best regards,
> Sanjeev
>
> diff --git a/arch/arm/plat-omap/include/mach/omap-pm.h b/arch/arm/plat-omap/include/mach/omap-pm.h
> index 583e540..2357784 100644
> --- a/arch/arm/plat-omap/include/mach/omap-pm.h
> +++ b/arch/arm/plat-omap/include/mach/omap-pm.h
> @@ -33,6 +33,20 @@ struct omap_opp {
>         u16 vsel;
>  };
>  
> +/* struct omap_opp_table - View OPP table as an object
> + * @min: Minimum OPP id
> + * @max: Maximim OPP id
> + * @opps: Pointer to array defining the OPPs.
> + *
> + * An OPP table has varied length. Knowing minimum and maximum
> + * OPP ids allow easy traversal.
> + */
> +struct omap_opp_table {
> +       u8      min;
> +       u8      max;
> +       struct omap_opp* opps;
> +};
> +
>  extern struct omap_opp *mpu_opps;
>  extern struct omap_opp *dsp_opps;
>  extern struct omap_opp *l3_opps;
> diff --git a/arch/arm/mach-omap2/pm.c b/arch/arm/mach-omap2/pm.c
> index fec7d00..c90b1af 100644
> --- a/arch/arm/mach-omap2/pm.c
> +++ b/arch/arm/mach-omap2/pm.c
> @@ -33,6 +33,7 @@
>  #include <mach/powerdomain.h>
>  #include <mach/resource.h>
>  #include <mach/omap34xx.h>
> +#include <mach/omap-pm.h>
>  
>  #include "prm-regbits-34xx.h"
>  #include "pm.h"
> @@ -281,3 +282,50 @@ static int __init omap_pm_init(void)
>         return error;
>  }
>  late_initcall(omap_pm_init);
> +
> +/*
> + * Get frequency corresponding to an OPP
> + */
> +int opp_to_freq(unsigned int* freq, struct omap_opp_table* table, u8 opp)
> +{
> +        int i, found=0;
> +
> +        if (table && table->opps) {
> +                for (i=table->min;  table->opps[i].opp_id <= table->max; i++)
> +                        if (table->opps[i].opp_id == opp) {
> +                                found = 1;
> +                                break;
> +                        }
> +
> +                if (found) {
> +                        *freq = table->opps[i].rate;
> +                        return 1;
> +                }
> +        }
> +
> +        return 0;
> +}
> +
> +/*
> + * Get OPP corresponding to a frequency
> + */
> +int freq_to_opp(u8* opp, struct omap_opp_table* table, unsigned long freq)
> +{
> +        int i, found=0;
> +
> +        if (table && table->opps) {
> +                for (i=table->min;  table->opps[i].opp_id <= table->max; i++)
> +                        if (table->opps[i].rate == freq) {
> +                                found = 1;
> +                                break;
> +                        }
> +
> +                if (found) {
> +                        *opp = table->opps[i].opp_id;
> +                        return 1;
> +                }
> +        }
> +
> +        return 0;
> +}
> +
> --
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