[PATCH 1/1] riscv: riscv_get_time() implementation for SMODE

[Anup Patel]

On Fri, Aug 14, 2020 at 11:15 PM Heinrich Schuchardt <xypron.glpk at gmx.de> wrote:
>
> On the Kendryte K210 OpenBSI cannot emulate the rdtime instruction. So we
> have to use the Sifive CLINT driver to provide riscv_get_time() in SMODE.

Can you elaborate why ?

The rdtime instruction should generate an illegal instruction fault which
OpenSBI will emulate.

Regards,
Anup

>
> Adjust Kconfig and Makefile to allow compiling the Sifive CLINT driver in
> SMODE.
>
> Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
> ---
>  arch/riscv/Kconfig                   | 16 +++++++++++-----
>  arch/riscv/cpu/fu540/Kconfig         |  3 ++-
>  arch/riscv/cpu/generic/Kconfig       |  3 ++-
>  arch/riscv/include/asm/global_data.h |  2 +-
>  arch/riscv/lib/Makefile              |  2 +-
>  5 files changed, 17 insertions(+), 9 deletions(-)
>
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index 009a545fcf..96c386225b 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -153,12 +153,18 @@ config 64BIT
>         bool
>
>  config SIFIVE_CLINT
> -       bool
> -       depends on RISCV_MMODE || SPL_RISCV_MMODE
> +       bool "SiFive's Core Local Interruptor (CLINT) driver"
>         select REGMAP
>         select SYSCON
> -       select SPL_REGMAP if SPL
> -       select SPL_SYSCON if SPL
> +       help
> +         The SiFive CLINT block holds memory-mapped control and status registers
> +         associated with software and timer interrupts.
> +
> +config SPL_SIFIVE_CLINT
> +       bool "SiFive's Core Local Interruptor (CLINT) driver in SPL"
> +       depends on SPL
> +       select SPL_REGMAP
> +       select SPL_SYSCON
>         help
>           The SiFive CLINT block holds memory-mapped control and status registers
>           associated with software and timer interrupts.
> @@ -186,7 +192,7 @@ config ANDES_PLMT
>           associated with timer tick.
>
>  config RISCV_RDTIME
> -       bool
> +       bool "Timer API via rdtime instruction"
>         default y if RISCV_SMODE || SPL_RISCV_SMODE
>         help
>           The provides the riscv_get_time() API that is implemented using the
> diff --git a/arch/riscv/cpu/fu540/Kconfig b/arch/riscv/cpu/fu540/Kconfig
> index 2dcad8e27f..8b2c83039f 100644
> --- a/arch/riscv/cpu/fu540/Kconfig
> +++ b/arch/riscv/cpu/fu540/Kconfig
> @@ -8,7 +8,8 @@ config SIFIVE_FU540
>         imply CPU
>         imply CPU_RISCV
>         imply RISCV_TIMER
> -       imply SIFIVE_CLINT if (RISCV_MMODE || SPL_RISCV_MMODE)
> +       imply SIFIVE_CLINT if RISCV_MMODE
> +       imply SPL_SIFIVE_CLINT if SPL_RISCV_MMODE
>         imply CMD_CPU
>         imply SPL_CPU_SUPPORT
>         imply SPL_OPENSBI
> diff --git a/arch/riscv/cpu/generic/Kconfig b/arch/riscv/cpu/generic/Kconfig
> index b2cb155d6d..62fcadd710 100644
> --- a/arch/riscv/cpu/generic/Kconfig
> +++ b/arch/riscv/cpu/generic/Kconfig
> @@ -8,7 +8,8 @@ config GENERIC_RISCV
>         imply CPU
>         imply CPU_RISCV
>         imply RISCV_TIMER
> -       imply SIFIVE_CLINT if (RISCV_MMODE || SPL_RISCV_MMODE)
> +       imply SIFIVE_CLINT if RISCV_MMODE
> +       imply SPL_SIFIVE_CLINT if SPL_RISCV_MMODE
>         imply CMD_CPU
>         imply SPL_CPU_SUPPORT
>         imply SPL_OPENSBI
> diff --git a/arch/riscv/include/asm/global_data.h b/arch/riscv/include/asm/global_data.h
> index 2eb14815bc..b89b469d41 100644
> --- a/arch/riscv/include/asm/global_data.h
> +++ b/arch/riscv/include/asm/global_data.h
> @@ -18,7 +18,7 @@
>  struct arch_global_data {
>         long boot_hart;         /* boot hart id */
>         phys_addr_t firmware_fdt_addr;
> -#ifdef CONFIG_SIFIVE_CLINT
> +#if CONFIG_IS_ENABLED(SIFIVE_CLINT)
>         void __iomem *clint;    /* clint base address */
>  #endif
>  #ifdef CONFIG_ANDES_PLIC
> diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile
> index 6c503ff2b2..861d7b489f 100644
> --- a/arch/riscv/lib/Makefile
> +++ b/arch/riscv/lib/Makefile
> @@ -10,8 +10,8 @@ obj-$(CONFIG_CMD_BOOTM) += bootm.o
>  obj-$(CONFIG_CMD_BOOTI) += bootm.o image.o
>  obj-$(CONFIG_CMD_GO) += boot.o
>  obj-y  += cache.o
> +obj-$(CONFIG_$(SPL_)SIFIVE_CLINT) += sifive_clint.o
>  ifeq ($(CONFIG_$(SPL_)RISCV_MMODE),y)
> -obj-$(CONFIG_SIFIVE_CLINT) += sifive_clint.o
>  obj-$(CONFIG_ANDES_PLIC) += andes_plic.o
>  obj-$(CONFIG_ANDES_PLMT) += andes_plmt.o
>  else
> --
> 2.28.0
>