Hi On Thu, Sep 07, 2023 at 03:39:57PM +0900, Chanho Park wrote:
Hi,
-----Original Message----- From: Heinrich Schuchardt heinrich.schuchardt@canonical.com Sent: Thursday, September 7, 2023 2:27 AM To: Chanho Park chanho61.park@samsung.com; Simon Glass sjg@chromium.org Cc: u-boot@lists.denx.de; Rick Chen rick@andestech.com; Leo ycliang@andestech.com 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 chanho61.park@samsung.com
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
Reviewed-by: Leo Yu-Chi Liang ycliang@andestech.com
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.
I think we could merge this patch set first, and then think more thoroghly about how we are going to clean this up.
Best regards, Leo
Best Regards, Chanho Park