[PATCH 1/3] riscv: Add timer_get_us() for tracing

[Bin Meng]

Hi Pragnesh,

On Mon, Aug 24, 2020 at 10:45 PM Pragnesh Patel
<pragnesh.patel at sifive.com> wrote:
>
> timer_get_us() will use timer_ops->get_count() function for timer counter.
> For S-mode U-Boot, CSR_TIMEH and CSR_TIME will provide a timer counter and
> For M-mode U-Boot, mtime register will provide the same.
>
> Signed-off-by: Pragnesh Patel <pragnesh.patel at sifive.com>
> ---
>  arch/riscv/lib/Makefile |  1 +
>  arch/riscv/lib/timer.c  | 50 +++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 51 insertions(+)
>  create mode 100644 arch/riscv/lib/timer.c
>
> diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile
> index 10ac5b06d3..fbb68e583b 100644
> --- a/arch/riscv/lib/Makefile
> +++ b/arch/riscv/lib/Makefile
> @@ -26,6 +26,7 @@ obj-y   += setjmp.o
>  obj-$(CONFIG_$(SPL_)SMP) += smp.o
>  obj-$(CONFIG_SPL_BUILD)        += spl.o
>  obj-y   += fdt_fixup.o
> +obj-$(CONFIG_TIMER) += timer.o
>
>  # For building EFI apps
>  CFLAGS_$(EFI_CRT0) := $(CFLAGS_EFI)
> diff --git a/arch/riscv/lib/timer.c b/arch/riscv/lib/timer.c
> new file mode 100644
> index 0000000000..3e423f2805
> --- /dev/null
> +++ b/arch/riscv/lib/timer.c
> @@ -0,0 +1,50 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (C) 2020 SiFive, Inc
> + *
> + * Authors:
> + *   Pragnesh Patel <pragnesh.patel at sifive.com>
> + */
> +
> +#include <common.h>
> +#include <dm.h>
> +#include <timer.h>
> +
> +DECLARE_GLOBAL_DATA_PTR;
> +
> +static struct udevice *timer;
> +
> +ulong notrace timer_get_us(void)

Does the weak one in lib/time.c not work on RISC-V?

> +{
> +       u64 count;
> +       ulong rate;
> +       int ret;
> +
> +       /**
> +        * gd->timer will become NULL in initr_dm(), so assign gd->timer
> +        * to other static global timer, so that timer_get_us() can use it.
> +        */
> +       if (!timer && gd->timer)
> +               timer = (struct udevice *)gd->timer;
> +
> +       if (timer) {
> +               ret = timer_get_count(timer, &count);
> +               if (ret)
> +                       return ret;
> +
> +               rate = timer_get_rate(timer);
> +       }
> +
> +       return (ulong)count / rate;
> +}
> +
> +int timer_init(void)

Why is this function necessary?

> +{
> +       int ret;
> +
> +       ret = dm_timer_init();

Does enabling CONFIG_TIMER_EARLY help?

> +       if (ret)
> +               return ret;
> +
> +       return 0;
> +}

Regards,
Bin