Messages in this thread | | | Subject | Re: [RFC PATCH] clocksource: dw_apb_timer_of: support timer-based delay | From | Daniel Lezcano <> | Date | Tue, 27 Oct 2015 01:41:53 +0100 |
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On 10/20/2015 10:11 AM, Jisheng Zhang wrote: > Implement an ARM delay timer to be used for udelay(). This allows us to > skip the delay loop calibration at boot on Marvell BG2, BG2Q, BG2CD > platforms. And after this patch, udelay() will be unaffected by CPU > frequency changes. > > But, this driver is not only used on ARM platforms, so I dunno how to > handle other platforms which don't have the register_current_timer_delay > That's the reason I mark this patch as RFC. > > Any suggestions are appreciated.
hmm, may be a dt-binding makes sense...
> Signed-off-by: Jisheng Zhang <jszhang@marvell.com> > --- > drivers/clocksource/dw_apb_timer_of.c | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/drivers/clocksource/dw_apb_timer_of.c b/drivers/clocksource/dw_apb_timer_of.c > index a19a3f6..09dbf9c 100644 > --- a/drivers/clocksource/dw_apb_timer_of.c > +++ b/drivers/clocksource/dw_apb_timer_of.c > @@ -16,6 +16,7 @@ > * You should have received a copy of the GNU General Public License > * along with this program. If not, see <http://www.gnu.org/licenses/>. > */ > +#include <linux/delay.h> > #include <linux/dw_apb_timer.h> > #include <linux/of.h> > #include <linux/of_address.h> > @@ -130,6 +131,15 @@ static void __init init_sched_clock(void) > sched_clock_register(read_sched_clock, 32, sched_rate); > } > > +static unsigned long dw_apb_delay_timer_read(void) > +{ > + return ~readl_relaxed(sched_io_base); > +} > + > +static struct delay_timer dw_apb_delay_timer = { > + .read_current_timer = dw_apb_delay_timer_read, > +}; > + > static int num_called; > static void __init dw_apb_timer_init(struct device_node *timer) > { > @@ -142,6 +152,8 @@ static void __init dw_apb_timer_init(struct device_node *timer) > pr_debug("%s: found clocksource timer\n", __func__); > add_clocksource(timer); > init_sched_clock(); > + dw_apb_delay_timer.freq = sched_rate; > + register_current_timer_delay(&dw_apb_delay_timer); > break; > default: > break; >
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