| Message ID | 1408373917-10002-7-git-send-email-matthias.bgg@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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 > >
2014-08-18 17:45 GMT+02:00 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? Oh sorry, my fault. In v2 I moved the frequency to the dts, as this will make the driver write CNTFRQ. I forgot to update the commit message. > >> In the future this should be done in the bootloader. > > Do we know how far in the future that's likely to be? AFAIK no one right now is working on an open source bootloader for the mediatek devices. So I think we won't see an open source bootloader in a reasonable time. > > What's the plan for this code when such a bootloader becomes available? I think when a bootloader becomes available, this code should be removed. I know that this will lead to a not working ARM arch timer in devices which don't migrate to the new bootloader, but I think it's not too critical. Apart from the ARM arch timer, the devices have the mediatek global porpose timer (drivers/clocksource/mtk_timer.c), which implement a clock source and a clock event timer. So the system won't hang. Cheers, Matthias > > 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 >> >>
On Thu, Aug 21, 2014 at 11:38:20AM +0100, Matthias Brugger wrote: > 2014-08-18 17:45 GMT+02:00 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? > > Oh sorry, my fault. In v2 I moved the frequency to the dts, as this > will make the driver write CNTFRQ. > I forgot to update the commit message. The arch timer driver does not write CNTFRQ as this can only be done from the secure side. It simply uses the value provided internally. This isn't sufficient for virtualization guests (which need to have CNTFRQ programmed correctly). For the moment as we're not booting at Hyp that's not necessarily a big problem, but it is a shame. > >> In the future this should be done in the bootloader. > > > > Do we know how far in the future that's likely to be? > > AFAIK no one right now is working on an open source bootloader for the > mediatek devices. > So I think we won't see an open source bootloader in a reasonable time. Ok. :( > > What's the plan for this code when such a bootloader becomes available? > > I think when a bootloader becomes available, this code should be > removed. I know that this will lead to a not working ARM arch timer in > devices which don't migrate to the new bootloader, but I think it's > not too critical. Apart from the ARM arch timer, the devices have the > mediatek global porpose timer (drivers/clocksource/mtk_timer.c), which > implement a clock source and a clock event timer. So the system won't > hang. I fear that's never going to happen, either because such a bootloader never becomes available or because there will be hold-outs sticking to the old loader. If that's not critical, why not for the moment use the global timer? Thanks, Mark.
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
We enable GTP6 which ungates the arch timer clock. Apart we write the frequency with which the timer is running in the CNTFREQ register. In the future this should be done in the bootloader. Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com> --- arch/arm/mach-mediatek/mediatek.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+)