[PATCH v2 1/1] bsp/riscv: Work area size based on /memory node in fdt

[Hesham Almatary]

All good, I'd just replace the "end == 0" with "end == NULL" as per my
comment above. Also please test on other RISC-V QEMU platforms to make
sure nothing got broken.

On Wed, 17 Aug 2022 at 14:10, Joel Sherrill <joel at rtems.org> wrote:
>
> I'm ok with this if Hesham acks as well.
>
> --joel
>
> On Wed, Aug 17, 2022 at 6:35 AM 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/shared/start/bspgetworkarea.c | 144 +++++++++++++++++++++++
>>  spec/build/bsps/riscv/riscv/obj.yml      |   1 +
>>  2 files changed, 145 insertions(+)
>>  create mode 100644 bsps/riscv/shared/start/bspgetworkarea.c
>>
>> diff --git a/bsps/riscv/shared/start/bspgetworkarea.c b/bsps/riscv/shared/start/bspgetworkarea.c
>> new file mode 100644
>> index 0000000000..1fa051d25e
>> --- /dev/null
>> +++ b/bsps/riscv/shared/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) {
>> +    /* 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/riscv/obj.yml b/spec/build/bsps/riscv/riscv/obj.yml
>> index 5e767be1bb..b2eb467824 100644
>> --- a/spec/build/bsps/riscv/riscv/obj.yml
>> +++ b/spec/build/bsps/riscv/riscv/obj.yml
>> @@ -29,6 +29,7 @@ source:
>>  - bsps/riscv/riscv/irq/irq.c
>>  - bsps/riscv/riscv/start/bsp_fatal_halt.c
>>  - bsps/riscv/riscv/start/bspstart.c
>> +- bsps/riscv/shared/start/bspgetworkarea.c
>>  - bsps/shared/cache/nocache.c
>>  - bsps/shared/dev/btimer/btimer-cpucounter.c
>>  - bsps/shared/dev/getentropy/getentropy-cpucounter.c
>> --
>> 2.34.1
>>
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