Hi, > -----Original Message----- > From: Heinrich Schuchardt <[email protected]> > Sent: Thursday, September 7, 2023 2:27 AM > To: Chanho Park <[email protected]>; Simon Glass > <[email protected]> > Cc: [email protected]; Rick Chen <[email protected]>; Leo > <[email protected]> > Subject: Re: [PATCH v3 3/3] timer: riscv_aclint_timer: add > timer_get_boot_us for BOOTSTAGE > > On 06.09.23 07:18, Chanho Park wrote: > > timer_get_boot_us function is required to record the boot stages as > > us-based timestamp. > > To get a micro-second time from a timer tick, this converts the > > formula like below to avoid zero result of (tick / rate) part. > > > > From: time(us) = (tick / rate) * 10000000 Still typo 10000000 -> 1000000 > > Where is the old implementation that you refer to?
I referred it from timer_get_boot_us function of lib/time.c lib/time.c 55 else if (timer_rate > 1000000) 56 return lldiv(count, timer_rate / 1000000); 57 else 58 return (unsigned long long)count * 1000000 / timer_rate; > > > To : time(us) = (tick * 1000) / (rate / 1000) > > > > Signed-off-by: Chanho Park <[email protected]> > > --- > > drivers/timer/riscv_aclint_timer.c | 23 +++++++++++++++++++++++ > > 1 file changed, 23 insertions(+) > > > > diff --git a/drivers/timer/riscv_aclint_timer.c > b/drivers/timer/riscv_aclint_timer.c > > index e29d527c8d77..73fb87912851 100644 > > --- a/drivers/timer/riscv_aclint_timer.c > > +++ b/drivers/timer/riscv_aclint_timer.c > > @@ -6,6 +6,7 @@ > > > > #include <common.h> > > #include <clk.h> > > +#include <div64.h> > > #include <dm.h> > > #include <timer.h> > > #include <asm/io.h> > > @@ -44,6 +45,28 @@ u64 notrace timer_early_get_count(void) > > } > > #endif > > > > +#if CONFIG_IS_ENABLED(RISCV_MMODE) && CONFIG_IS_ENABLED(BOOTSTAGE) > > +ulong timer_get_boot_us(void) > > +{ > > + int ret; > > + u64 ticks = 0; > > + u32 rate; > > + > > + ret = dm_timer_init(); > > + if (!ret) { > > + rate = timer_get_rate(gd->timer); > > + timer_get_count(gd->timer, &ticks); > > + } else { > > + rate = RISCV_MMODE_TIMER_FREQ; > > + ticks = readq((void __iomem > *)MTIME_REG(RISCV_MMODE_TIMERBASE, > > + RISCV_MMODE_TIMEROFF)); > > + } > > + > > + /* Below is converted from time(us) = (tick / rate) * 10000000 */ > > + return lldiv(ticks * 1000, (rate / 1000)); > > I found similar code in drivers/timer/cadence-ttc.c and > drivers/timer/omap-timer.c with > > us = (ticks * 1000) / rate; > return us. > > Either their code or yours must be wrong. > > What I am missing in include/timer.h is a documentation that defines if > timer_dev_priv.clock_rate and timer_get_rate() yield the frequency in Hz > or kHz. 'rate' seems to be Hz not kHz. So, I think they need to be corrected. > > Once we have added the missing information in the include we can start > reviewing this patch. > > I really dislike that we have code per architecture and don't update and > use a implementation in lib/time.c (where we also have an > implementation) or drivers/timer/timer-uclass.c. Can't we have a single > implementation which is driver model based and eliminate all others? Actually, I tried to use lib/time.c's implementation or make a generic function in timer-uclass.c as you mentioned. However, there are different implementations in cadence-ttc.c, rockchip_timer.c, tegra-timer.c, omap-timer.c and tsc_timer.c. The basic codes seems to be almost identical if we can get a DM timer successfully but fallback codes look different. If timer_get_boot_us can be implement in the timer-uclass.c, we still need per-driver callback function for supporting these different fallback codes. Best Regards, Chanho Park
