struct dmtimer definition not available in header file

struct dmtimer definition not available in header file

[Gurav , Pramod]

Hi All,
I am using dmtimer in my code. Code looks like this:

{
        static struct omap_dm_timer *gpt;
        void * __iomem gpt10_counter_reg;
        unsigned long gpt_phys_base;

        omap_dm_timer_init();
        gpt = omap_dm_timer_request();
        if (!gpt) {
                pr_err("Could not get the gptimer\n");
                return -1;
        }
        omap_dm_timer_set_source(gpt, OMAP_TIMER_SRC_SYS_CLK);

        gpt_phys_base = gpt->phys_base;

        gpt10_counter_reg =
                        OMAP2_L4_IO_ADDRESS(gpt_phys_base +
                                        OMAP_TIMER_COUNTER_OFFSET);

        gt_rate = clk_get_rate(omap_dm_timer_get_fclk(gpt));
        omap_dm_timer_set_load_start(gpt, 0, 0);
	
	.
	.
	.
}

I am not able to reference *gpt as the file does not know about struct omap_dm_timer. I have included plat/dmtimer.h.

Why doesn't the dmtimer struct definition appear in plat/dmtimer.h ?
Is there any reason for this?

-
Thanks and Best Regards
Pramod Gurav

Re: struct dmtimer definition not available in header file

[Kevin Hilman]

"Gurav , Pramod" <pramod.gurav@ti.com> writes:

> Hi All,
> I am using dmtimer in my code. Code looks like this:
>
> {
>         static struct omap_dm_timer *gpt;
>         void * __iomem gpt10_counter_reg;
>         unsigned long gpt_phys_base;
>
>         omap_dm_timer_init();
>         gpt = omap_dm_timer_request();
>         if (!gpt) {
>                 pr_err("Could not get the gptimer\n");
>                 return -1;
>         }
>         omap_dm_timer_set_source(gpt, OMAP_TIMER_SRC_SYS_CLK);
>
>         gpt_phys_base = gpt->phys_base;
>
>         gpt10_counter_reg =
>                         OMAP2_L4_IO_ADDRESS(gpt_phys_base +
>                                         OMAP_TIMER_COUNTER_OFFSET);
>
>         gt_rate = clk_get_rate(omap_dm_timer_get_fclk(gpt));
>         omap_dm_timer_set_load_start(gpt, 0, 0);
> 	
> 	.
> 	.
> 	.
> }
>
> I am not able to reference *gpt as the file does not know about struct omap_dm_timer. I have included plat/dmtimer.h.
>
> Why doesn't the dmtimer struct definition appear in plat/dmtimer.h ?
> Is there any reason for this?

The declaration appears there, but the definition is hidden.

In fact, it is is hidden to prevent exactly the type of thing you're
trying to do, and to provide all access to DM timer details via the DM
timer API.

Looking at your example, I'm guessing you're trying to implement one
of my ideas for the SDRC delay calculation by passing the base address
to the assembly routine.

As I suggested in my original patch, the better way to do this would
be to extend the dmtimer API, and use C instead of assembly.

Kevin

RE: struct dmtimer definition not available in header file

[Cousson, Benoit]

>From: linux-omap-owner@vger.kernel.org [mailto:linux-omap-
>owner@vger.kernel.org] On Behalf Of Kevin Hilman
>Sent: Wednesday, March 10, 2010 6:01 PM
>
>"Gurav , Pramod" <pramod.gurav@ti.com> writes:
>
>> Hi All,
>> I am using dmtimer in my code. Code looks like this:
>>
>> {
>>         static struct omap_dm_timer *gpt;
>>         void * __iomem gpt10_counter_reg;
>>         unsigned long gpt_phys_base;
>>
>>         omap_dm_timer_init();
>>         gpt = omap_dm_timer_request();
>>         if (!gpt) {
>>                 pr_err("Could not get the gptimer\n");
>>                 return -1;
>>         }
>>         omap_dm_timer_set_source(gpt, OMAP_TIMER_SRC_SYS_CLK);
>>
>>         gpt_phys_base = gpt->phys_base;
>>
>>         gpt10_counter_reg =
>>                         OMAP2_L4_IO_ADDRESS(gpt_phys_base +
>>                                         OMAP_TIMER_COUNTER_OFFSET);
>>
>>         gt_rate = clk_get_rate(omap_dm_timer_get_fclk(gpt));
>>         omap_dm_timer_set_load_start(gpt, 0, 0);
>>
>>      .
>>      .
>>      .
>> }
>>
>> I am not able to reference *gpt as the file does not know about struct
>omap_dm_timer. I have included plat/dmtimer.h.
>>
>> Why doesn't the dmtimer struct definition appear in plat/dmtimer.h ?
>> Is there any reason for this?
>
>The declaration appears there, but the definition is hidden.
>
>In fact, it is is hidden to prevent exactly the type of thing you're
>trying to do, and to provide all access to DM timer details via the DM
>timer API.
>
>Looking at your example, I'm guessing you're trying to implement one
>of my ideas for the SDRC delay calculation by passing the base address
>to the assembly routine.
>
>As I suggested in my original patch, the better way to do this would
>be to extend the dmtimer API, and use C instead of assembly.

Considering the accuracy needed in that case and the number of iteration (10000), I clearly don't think we need to ack the dmtimer API to read the timer value in ASM.
Using the regular omap_dm_timer_read_counter before and after calling the ASM function will be enough.
Moreover the current ASM function can be simplify to reduce the overhead.

Regards,
Benoit

Texas Instruments France SA, 821 Avenue Jack Kilby, 06270 Villeneuve Loubet. 036 420 040 R.C.S Antibes. Capital de EUR 753.920

RE: struct dmtimer definition not available in header file

[Gurav , Pramod]

Hi Benoit, Kelvin,

> >>                         OMAP2_L4_IO_ADDRESS(gpt_phys_base +
> >>                                         OMAP_TIMER_COUNTER_OFFSET);
> >>
> >>         gt_rate = clk_get_rate(omap_dm_timer_get_fclk(gpt));
> >>         omap_dm_timer_set_load_start(gpt, 0, 0);
> >>
> >> 	.
> >> 	.
> >> 	.
> >> }
> >>
> >> I am not able to reference *gpt as the file does not know about struct
> >omap_dm_timer. I have included plat/dmtimer.h.
> >>
> >> Why doesn't the dmtimer struct definition appear in plat/dmtimer.h ?
> >> Is there any reason for this?
> >
> >The declaration appears there, but the definition is hidden.
> >
> >In fact, it is is hidden to prevent exactly the type of thing you're
> >trying to do, and to provide all access to DM timer details via the DM
> >timer API.
> >
> >Looking at your example, I'm guessing you're trying to implement one
> >of my ideas for the SDRC delay calculation by passing the base address
> >to the assembly routine.
> >
> >As I suggested in my original patch, the better way to do this would
> >be to extend the dmtimer API, and use C instead of assembly.
> 
> Considering the accuracy needed in that case and the number of iteration
> (10000), I clearly don't think we need to ack the dmtimer API to read the
> timer value in ASM.
> Using the regular omap_dm_timer_read_counter before and after calling the
> ASM function will be enough.
> Moreover the current ASM function can be simplify to reduce the overhead.
>

Thank you.
I am trying with DMtimer API. I will even reduce the dmtimer part of ASM code and run only the loop in ASM.


Thanks and Regards
Pramod

RE: struct dmtimer definition not available in header file

[Cousson, Benoit]

>From: Gurav , Pramod
>Sent: Thursday, March 11, 2010 5:57 AM
>To: Cousson, Benoit; Kevin Hilman
>Cc: linux-omap@vger.kernel.org
>Subject: RE: struct dmtimer definition not available in header file
>
>Hi Benoit, Kelvin,
>
>> >>                         OMAP2_L4_IO_ADDRESS(gpt_phys_base +
>> >>                                         OMAP_TIMER_COUNTER_OFFSET);
>> >>
>> >>         gt_rate = clk_get_rate(omap_dm_timer_get_fclk(gpt));
>> >>         omap_dm_timer_set_load_start(gpt, 0, 0);
>> >>
>> >>   .
>> >>   .
>> >>   .
>> >> }
>> >>
>> >> I am not able to reference *gpt as the file does not know about struct
>> >omap_dm_timer. I have included plat/dmtimer.h.
>> >>
>> >> Why doesn't the dmtimer struct definition appear in plat/dmtimer.h ?
>> >> Is there any reason for this?
>> >
>> >The declaration appears there, but the definition is hidden.
>> >
>> >In fact, it is is hidden to prevent exactly the type of thing you're
>> >trying to do, and to provide all access to DM timer details via the DM
>> >timer API.
>> >
>> >Looking at your example, I'm guessing you're trying to implement one
>> >of my ideas for the SDRC delay calculation by passing the base address
>> >to the assembly routine.
>> >
>> >As I suggested in my original patch, the better way to do this would
>> >be to extend the dmtimer API, and use C instead of assembly.
>>
>> Considering the accuracy needed in that case and the number of iteration
>> (10000), I clearly don't think we need to ack the dmtimer API to read the
>> timer value in ASM.
>> Using the regular omap_dm_timer_read_counter before and after calling the
>> ASM function will be enough.
>> Moreover the current ASM function can be simplify to reduce the overhead.
>>
>
>Thank you.
>I am trying with DMtimer API. I will even reduce the dmtimer part of ASM
>code and run only the loop in ASM.

Yes, that was my point; without the timer access the asm function will have only 3 instructions.

Regards,
Benoit

>
>Thanks and Regards
>Pramod

Texas Instruments France SA, 821 Avenue Jack Kilby, 06270 Villeneuve Loubet. 036 420 040 R.C.S Antibes. Capital de EUR 753.920

Re: struct dmtimer definition not available in header file

[Tony Lindgren]

* Kevin Hilman <khilman@deeprootsystems.com> [100310 09:14]:
> "Gurav , Pramod" <pramod.gurav@ti.com> writes:
> 
> > Hi All,
> > I am using dmtimer in my code. Code looks like this:
> >
> > {
> >         static struct omap_dm_timer *gpt;
> >         void * __iomem gpt10_counter_reg;
> >         unsigned long gpt_phys_base;
> >
> >         omap_dm_timer_init();
> >         gpt = omap_dm_timer_request();
> >         if (!gpt) {
> >                 pr_err("Could not get the gptimer\n");
> >                 return -1;
> >         }
> >         omap_dm_timer_set_source(gpt, OMAP_TIMER_SRC_SYS_CLK);
> >
> >         gpt_phys_base = gpt->phys_base;
> >
> >         gpt10_counter_reg =
> >                         OMAP2_L4_IO_ADDRESS(gpt_phys_base +
> >                                         OMAP_TIMER_COUNTER_OFFSET);

We should use ioremap for allthings like this nowadays.
There are static mappings in place for that.

> >         gt_rate = clk_get_rate(omap_dm_timer_get_fclk(gpt));
> >         omap_dm_timer_set_load_start(gpt, 0, 0);
> > 	
> > 	.
> > 	.
> > 	.
> > }
> >
> > I am not able to reference *gpt as the file does not know about struct omap_dm_timer. I have included plat/dmtimer.h.
> >
> > Why doesn't the dmtimer struct definition appear in plat/dmtimer.h ?
> > Is there any reason for this?
> 
> The declaration appears there, but the definition is hidden.
> 
> In fact, it is is hidden to prevent exactly the type of thing you're
> trying to do, and to provide all access to DM timer details via the DM
> timer API.
> 
> Looking at your example, I'm guessing you're trying to implement one
> of my ideas for the SDRC delay calculation by passing the base address
> to the assembly routine.
> 
> As I suggested in my original patch, the better way to do this would
> be to extend the dmtimer API, and use C instead of assembly.

And if it's generic code, you're better off using Linux hrtimers
instead. Otherwise there's a good chance your timer won't wake up
the system from the idle mode and you miss the timer events.

Regards,

Tony