On Mon, Dec 3, 2012 at 10:01 PM, Hiremath, Vaibhav <hvaibhav@xxxxxx> wrote:
>
> On Mon, Dec 03, 2012 at 23:49:36, Kevin Hilman wrote:
> > "Hiremath, Vaibhav" <hvaibhav@xxxxxx> writes:
> >
> > >> >>> +static struct omap_hwmod am33xx_debugss_hwmod = {
> > >> >>> + .name = "debugss",
> > >> >>> + .class = &am33xx_debugss_hwmod_class,
> > >> >>> + .clkdm_name = "l3_aon_clkdm",
> > >> >>> + .main_clk = "debugss_ick",
> > >> >>> + .flags = (HWMOD_INIT_NO_IDLE |
> > >> >>> HWMOD_INIT_NO_RESET),
> > >>
> > >> Setting these flags would still leave the problem where JTAG clocks
> > >> are on when its not required no? In that case, what is the advantage
> > >> of this patch?
> > >>
> > >
> > > I missed to wrap it around #ifdef CONFIG_DEBUG_KERNEL. I will submit
> > > the
> > > formal patch shortly.
> >
> > IMO, this should not be handled in the data at all (neither clock nor
> > hwmod), and should be handled at runtime/boot-time, not compile time.
> >
>
> Wouldn't that become another interface/control for debug? We already have
> various (standard) debug kernel parameters available.
>
> But I see your point, compile-time option will force users to rebuild
> kernel
> just in order to disable JTAG/Debug clock.
>
> > The solution to this is to rather to have a small bit of code that
> > requests the debugss clocks that are needed for JTAG debug, so the
> > kernel knows they are in use.
> >
> > That code could then be enabled at boot time via command-line or DT
> > option.
> >
>
> In case of command-line, something like below???
>
> static int __init omap2_debug_clk_enable(char *str)
> {
> if (!str)
> return 0;
>
> if (!strcmp(str, "debug"))
> <enable debug clock>
>
> return 0;
> }
> early_param("debug", omap2_debug_clk_enable);
>
This approach looks , I wrote similar code replacing "enable debug clock" with:
jtag_clk = clk_get(NULL, "debugss_ick");
if(!IS_ERR_OR_NULL(jtag_clk))
clk_enable(jtag_clk);
>
> In case of DT, one thought,
>
> It can be part of omap_generic_init() in board-generic.c file,
> We can parse there for debug node and required property to enable debug
> module.
>
> Any thought? Or Other options???
Not sure, but can we append to bootargs from DT itself thus the above
cmdline code can be used to enable debugss for both regular bootargs
as well DT?
Regards,
Joel
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