[PATCH] bsp/riscv: Work area size based on /memory node in fdt

[Hesham Almatary]

Thanks for the patch. LGTM. I wonder if we can also reuse that for the
generic shared RISC-V BSP (e.g., bsps/riscv/riscv) instead of just NOEL?

On Wed, 17 Aug 2022 at 09:58, Daniel Cederman <cederman at gaisler.com> wrote:

> Uses the first entry in the /memory node to determine the end of the
> work area. Falls back on linker symbol if unable to parse the node.
> ---
>  bsps/riscv/noel/start/bspgetworkarea.c | 144 +++++++++++++++++++++++++
>  spec/build/bsps/riscv/noel/obj.yml     |   1 +
>  2 files changed, 145 insertions(+)
>  create mode 100644 bsps/riscv/noel/start/bspgetworkarea.c
>
> diff --git a/bsps/riscv/noel/start/bspgetworkarea.c
> b/bsps/riscv/noel/start/bspgetworkarea.c
> new file mode 100644
> index 0000000000..1fa051d25e
> --- /dev/null
> +++ b/bsps/riscv/noel/start/bspgetworkarea.c
> @@ -0,0 +1,144 @@
> +/* SPDX-License-Identifier: BSD-2-Clause */
> +
> +/**
> + * @file
> + *
> + * @brief BSP specific initialization support routines
> + *
> + */
> +
> +/*
> + * COPYRIGHT (c) 1989-2020.
> + * On-Line Applications Research Corporation (OAR).
> + * Cobham Gaisler AB.
> + *
> + * Redistribution and use in source and binary forms, with or without
> + * modification, are permitted provided that the following conditions
> + * are met:
> + * 1. Redistributions of source code must retain the above copyright
> + *    notice, this list of conditions and the following disclaimer.
> + * 2. Redistributions in binary form must reproduce the above copyright
> + *    notice, this list of conditions and the following disclaimer in the
> + *    documentation and/or other materials provided with the distribution.
> + *
> + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
> "AS IS"
> + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
> THE
> + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
> PURPOSE
> + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
> BE
> + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
> + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
> + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
> BUSINESS
> + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
> + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
> + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
> THE
> + * POSSIBILITY OF SUCH DAMAGE.
> + */
> +
> +#include <bsp.h>
> +#include <bsp/fdt.h>
> +
> +#include <rtems/sysinit.h>
> +
> +#include <libfdt.h>
> +
> +/*
> + *  These are provided by the linkcmds for ALL of the BSPs which use this
> file.
> + */
> +extern char WorkAreaBase[];
> +extern char RamEnd[];
> +
> +static Memory_Area _Memory_Areas[ 1 ];
> +
> +static const char memory_path[] = "/memory";
> +
> +static void* get_end_of_memory_from_fdt(void)
> +{
> +  const void *fdt;
> +  const void *val;
> +  int node;
> +  int parent;
> +  int ac;
> +  int sc;
> +  int len;
> +  uintptr_t start;
> +  uintptr_t size;
> +
> +  fdt = bsp_fdt_get();
> +
> +  node = fdt_path_offset_namelen(
> +    fdt,
> +    memory_path,
> +    (int) sizeof(memory_path) - 1
> +  );
> +
> +  if (node < 0) {
> +    return NULL;
> +  }
> +
> +  parent = fdt_parent_offset(fdt, node);
> +  if (parent < 0) {
> +    return NULL;
> +  }
> +
> +  ac = fdt_address_cells(fdt, parent);
> +  if (ac != 1 && ac != 2) {
> +    return NULL;
> +  }
> +
> +  sc = fdt_size_cells(fdt, parent);
> +  if (sc != 1 && sc != 2) {
> +    return NULL;
> +  }
> +
> +  if (sc > ac) {
> +    return NULL;
> +  }
> +
> +  val = fdt_getprop(fdt, node, "reg", &len);
> +  if (len < sc + ac) {
> +    return NULL;
> +  }
> +
> +  if (ac == 1) {
> +    start = fdt32_to_cpu(((fdt32_t *)val)[0]);
> +    size = fdt32_to_cpu(((fdt32_t *)val)[1]);
> +  }
> +
> +  if (ac == 2) {
> +    start = fdt64_to_cpu(((fdt64_t *)val)[0]);
> +
> +    if (sc == 1)
> +      size = fdt32_to_cpu(((fdt32_t *)(val+8))[0]);
> +    else
> +      size = fdt64_to_cpu(((fdt64_t *)val)[1]);
> +  }
> +
> +  return (void*) (start + size);
> +}
> +
> +static void bsp_memory_initialize( void )
> +{
> +  void *end;
> +
> +  /* get end of memory from the "/memory" node in the fdt */
> +  end = get_end_of_memory_from_fdt();
> +  if (end == 0) {
>
NULL instead of 0?


> +    /* fall back to linker symbol if "/memory" node not found or invalid
> */
> +    end = RamEnd;
> +  }
> +  _Memory_Initialize( &_Memory_Areas[ 0 ], WorkAreaBase, end );
> +}
> +
> +RTEMS_SYSINIT_ITEM(
> +  bsp_memory_initialize,
> +  RTEMS_SYSINIT_MEMORY,
> +  RTEMS_SYSINIT_ORDER_MIDDLE
> +);
> +
> +static const Memory_Information _Memory_Information =
> +  MEMORY_INFORMATION_INITIALIZER( _Memory_Areas );
> +
> +const Memory_Information *_Memory_Get( void )
> +{
> +  return &_Memory_Information;
> +}
> diff --git a/spec/build/bsps/riscv/noel/obj.yml
> b/spec/build/bsps/riscv/noel/obj.yml
> index e1b652fa93..f9902f83b5 100644
> --- a/spec/build/bsps/riscv/noel/obj.yml
> +++ b/spec/build/bsps/riscv/noel/obj.yml
> @@ -22,6 +22,7 @@ source:
>  - bsps/riscv/noel/console/console-config.c
>  - bsps/riscv/riscv/irq/irq.c
>  - bsps/riscv/noel/start/bsp_fatal_halt.c
> +- bsps/riscv/noel/start/bspgetworkarea.c
>  - bsps/riscv/riscv/start/bspstart.c
>  - bsps/shared/cache/nocache.c
>  - bsps/shared/dev/btimer/btimer-cpucounter.c
> --
> 2.34.1
>
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