Re: [PATCH v2 6/9] arm: mediatek: enable gpt6 on boot up to make arch timer working

[Mark Rutland <mark.rutland@arm.com>]

Hi Matthias,

On Mon, Aug 18, 2014 at 03:58:34PM +0100, Matthias Brugger wrote:
> We enable GTP6 which ungates the arch timer clock. Apart we write the
> frequency with which the timer is running in the CNTFREQ register.

We don't seem to set CNTFRQ below. Does it happen to have a consistent
value on current versions of the bootloader?

> In the future this should be done in the bootloader.

Do we know how far in the future that's likely to be?

What's the plan for this code when such a bootloader becomes available?

Thanks,
Mark.

> Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>
> ---
>  arch/arm/mach-mediatek/mediatek.c |   26 ++++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
> 
> diff --git a/arch/arm/mach-mediatek/mediatek.c b/arch/arm/mach-mediatek/mediatek.c
> index f2acf07..2989f18 100644
> --- a/arch/arm/mach-mediatek/mediatek.c
> +++ b/arch/arm/mach-mediatek/mediatek.c
> @@ -16,6 +16,31 @@
>   */
>  #include <linux/init.h>
>  #include <asm/mach/arch.h>
> +#include <linux/of.h>
> +#include <linux/clk-provider.h>
> +#include <linux/clocksource.h>
> +
> +#define TIMER_CTRL_OP_FREERUN	0x30
> +#define TIMER_CTRL_ENABLE	0x01
> +
> +#define GPT6_CON_MT65xx 0x10008060
> +
> +static void __init mediatek_timer_init(void)
> +{
> +	static void __iomem *gpt_base;
> +
> +	if (of_machine_is_compatible("mediatek,mt6589")) {
> +		/* turn on GPT6 which ungates arch timer clocks */
> +		gpt_base = ioremap(GPT6_CON_MT65xx, 0x04);
> +	}
> +
> +	/* enabel clock and set to free-run */
> +	if (gpt_base)
> +		writel(TIMER_CTRL_OP_FREERUN | TIMER_CTRL_ENABLE, gpt_base);
> +
> +	of_clk_init(NULL);
> +	clocksource_of_init();
> +};
>  
>  static const char * const mediatek_board_dt_compat[] = {
>  	"mediatek,mt6589",
> @@ -24,4 +49,5 @@ static const char * const mediatek_board_dt_compat[] = {
>  
>  DT_MACHINE_START(MEDIATEK_DT, "Mediatek Cortex-A7 (Device Tree)")
>  	.dt_compat	= mediatek_board_dt_compat,
> +	.init_time	= mediatek_timer_init,
>  MACHINE_END
> -- 
> 1.7.9.5
> 
>