"Premi, Sanjeev" <premi@xxxxxx> writes: >> -----Original Message----- >> From: Kevin Hilman [mailto:khilman@xxxxxxxxxxxxxxxxxxx] >> Sent: Friday, September 11, 2009 12:00 AM >> To: Premi, Sanjeev >> Cc: linux-omap@xxxxxxxxxxxxxxx >> Subject: Re: [RFC] OMAP3 : PM : Handle variable length OPP tables >> >> "Premi, Sanjeev" <premi@xxxxxx> 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... >> > >> > Best regards, >> > Sanjeev >> >> Is the goal of the min and max fields so you could have some OPPs >> in the table that aren't valid for some SoCs? IOW, the 'max' value >> might be higher on newer SoCs with higher OPPs. > > The goal is to have get_*() functions where caller shouldn't be aware > of the MAX_ for the table. Considering table as an object, it should > be able to provide its own length. > > Reason to use min and max was to maintain current functionality as is. > Else, simple 'length' should be sufficient. > >> >> What if you want a list of OPPs, but want to remove one from the >> middle of the list? The min/max approach doesn't work here. >> >> What about a also extending the struct omap_opp to have some sort of >> valid field. > > This doesn't help in eliminating the addition of MAX value for each > function call. No it doesn't. I'm just thinking about the next step of having a more flexible list of OPPs. Kevin >> >> > >> > 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; >> > +} >> > + >> > -- >> > To unsubscribe from this list: send the line "unsubscribe >> linux-omap" in >> > the body of a message to majordomo@xxxxxxxxxxxxxxx >> > More majordomo info at http://vger.kernel.org/majordomo-info.html >> >> -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
