Hi,
-----Original Message----- From: Leo Liang ycliang@andestech.com Sent: Monday, September 4, 2023 4:01 PM To: Chanho Park chanho61.park@samsung.com Cc: Rick Chen rick@andestech.com; Simon Glass sjg@chromium.org; u- boot@lists.denx.de Subject: Re: [PATCH v2 2/3] riscv: timer: add timer_get_boot_us for BOOTSTAGE
Hi Chanho,
On Mon, Aug 28, 2023 at 06:49:37PM +0900, Chanho Park wrote:
timer_get_boot_us function is required to record the boot stages as us-based timestamp.
Signed-off-by: Chanho Park chanho61.park@samsung.com
drivers/timer/riscv_timer.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+)
diff --git a/drivers/timer/riscv_timer.c b/drivers/timer/riscv_timer.c index 3627ed79b819..6cb589fcdc45 100644 --- a/drivers/timer/riscv_timer.c +++ b/drivers/timer/riscv_timer.c @@ -11,6 +11,7 @@ */
#include <common.h> +#include <div64.h> #include <dm.h> #include <errno.h> #include <timer.h> @@ -50,6 +51,26 @@ u64 notrace timer_early_get_count(void) } #endif
+#if CONFIG_IS_ENABLED(RISCV_SMODE) && 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_SMODE_TIMER_FREQ;ticks = riscv_timer_get_count(NULL);- }
- return lldiv(ticks * 1000, (rate / 1000));
Could you elaborate a little how this formula is derived?
Sure. Below is the original formula. To avoid zero of (tick/rate), I split the calculation to ticks and rate, respectively.
Time(us) = (ticks / rate) * 1000000 Or (ticks * 1000000) / rate Or tick / (rate / 10000000)
Best Regards, Chanho Park