[6/7] riscv: add CONFIG_API support

From: Mitchell Horne <mhorne at FreeBSD.org>

Add the necessary changes to allow building the CONFIG_API option on the
RISC-V architecture. The downstream consumer of this API is the u-boot
version of FreeBSD's loader(8). This enables the loader to be ported to
RISC-V.

Signed-off-by: Mitchell Horne <mhorne at FreeBSD.org>
Cc: rick at andestech.com
Cc: bmeng.cn at gmail.com
Cc: atish.patra at wdc.com
---
 api/Makefile             |  1 +
 api/api_platform-riscv.c | 33 +++++++++++++++++++++++++++++++++
 examples/api/Makefile    |  3 +++
 examples/api/crt0.S      | 15 +++++++++++++++
 4 files changed, 52 insertions(+)
 create mode 100644 api/api_platform-riscv.c

On Tue, Apr 21, 2020 at 6:35 AM <mhorne at freebsd.org> wrote:
>
> From: Mitchell Horne <mhorne at FreeBSD.org>
>
> Add the necessary changes to allow building the CONFIG_API option on the
> RISC-V architecture. The downstream consumer of this API is the u-boot
> version of FreeBSD's loader(8). This enables the loader to be ported to

Could you please include a URL for FreeBSD's loader(8)?

> RISC-V.
>
> Signed-off-by: Mitchell Horne <mhorne at FreeBSD.org>
> Cc: rick at andestech.com
> Cc: bmeng.cn at gmail.com
> Cc: atish.patra at wdc.com
> ---
>  api/Makefile             |  1 +
>  api/api_platform-riscv.c | 33 +++++++++++++++++++++++++++++++++
>  examples/api/Makefile    |  3 +++
>  examples/api/crt0.S      | 15 +++++++++++++++
>  4 files changed, 52 insertions(+)
>  create mode 100644 api/api_platform-riscv.c
>
> diff --git a/api/Makefile b/api/Makefile
> index bd2d035fcd..737854e2c6 100644
> --- a/api/Makefile
> +++ b/api/Makefile
> @@ -6,3 +6,4 @@ obj-y += api.o api_display.o api_net.o api_storage.o
>  obj-$(CONFIG_ARM) += api_platform-arm.o
>  obj-$(CONFIG_PPC) += api_platform-powerpc.o
>  obj-$(CONFIG_MIPS) += api_platform-mips.o
> +obj-$(CONFIG_RISCV) += api_platform-riscv.o
> diff --git a/api/api_platform-riscv.c b/api/api_platform-riscv.c
> new file mode 100644
> index 0000000000..33a56535f3
> --- /dev/null
> +++ b/api/api_platform-riscv.c
> @@ -0,0 +1,33 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * (C) Copyright 2007 Stanislav Galabov <sgalabov at gmail.com>
> + *
> + * This file contains routines that fetch data from bd_info sources
> + */
> +
> +#include <config.h>
> +#include <linux/types.h>
> +#include <api_public.h>
> +
> +#include <asm/u-boot.h>
> +#include <asm/global_data.h>
> +
> +#include "api_private.h"
> +
> +DECLARE_GLOBAL_DATA_PTR;
> +
> +/*
> + * Important notice: handling of individual fields MUST be kept in sync with
> + * include/asm-generic/u-boot.h, so any changes
> + * need to reflect their current state and layout of structures involved!
> + */
> +int platform_sys_info(struct sys_info *si)
> +{
> +       int i;
> +
> +       for (i = 0; i < CONFIG_NR_DRAM_BANKS; i++)
> +               platform_set_mr(si, gd->bd->bi_dram[i].start,
> +                               gd->bd->bi_dram[i].size, MR_ATTR_DRAM);
> +
> +       return 1;
> +}
> diff --git a/examples/api/Makefile b/examples/api/Makefile
> index 8fa9c04118..0f9d0e013f 100644
> --- a/examples/api/Makefile
> +++ b/examples/api/Makefile
> @@ -18,6 +18,9 @@ else
>  LOAD_ADDR = 0x80200000
>  endif
>  endif
> +ifeq ($(ARCH),riscv)
> +LOAD_ADDR = 0x84000000
> +endif
>
>  # Resulting ELF and binary exectuables will be named demo and demo.bin
>  extra-y = demo demo.bin
> diff --git a/examples/api/crt0.S b/examples/api/crt0.S
> index 658bc59a82..2ba23331df 100644
> --- a/examples/api/crt0.S
> +++ b/examples/api/crt0.S
> @@ -65,6 +65,21 @@ return_addr:
>         .data
>         .align 8
>         .long 0
> +
> +#elif defined(CONFIG_RISCV)
> +#include <asm/asm.h>
> +       .text
> +       .globl _start
> +_start:
> +       lla     t0, search_hint

Looks lla is only supported in newer assemblers?

> +       REG_S   sp, 0(t0)
> +       tail    main
> +
> +       .globl syscall
> +syscall:
> +       lla     t0, syscall_ptr
> +       REG_L   t2, 0(t0)
> +       jr      t2
>  #else
>  #error No support for this arch!
>  #endif
> --

Regards,
Bin