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lib: utils/fdt: Add support for parsing riscv,isa-extensions

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A new property has been added, with an extensive rationale at [1], that
can be used in place of "riscv,isa" to indicate what extensions are
supported by a given platform that is a list of strings rather than a
single string. There are some differences between the new property,
"riscv,isa-extensions" and the incumbent "riscv,isa" - chief among them
for the sake of parsing being the list of strings, as opposed to a
string. Another advantage is strictly defined meanings for each string
in a dt-binding, rather than deriving meaning from RVI standards. This
may likely to some divergence over time, but, at least for now, there's
no relevant differences between the two for an M-Mode program.

Add support for the new property in OpenSBI, prioritising it, before
falling back to the, now deprecated, "riscv,isa" property if it is not
present.

Link: https://lore.kernel.org/all/20230702-eats-scorebook-c951f170d29f@spud/ [1]
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
This commit is contained in:
Conor Dooley
2024-07-02 11:59:11 +01:00
committed by Anup Patel
parent b7e7e66026
commit f7a92f6b67
1 changed files with 23 additions and 4 deletions
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27
lib/utils/fdt/fdt_helper.c
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@@ -411,6 +411,18 @@ static int fdt_parse_isa_one_hart(const char *isa, unsigned long *extensions)
return 0;
}
static void fdt_parse_isa_extensions_one_hart(const char *isa,
unsigned long *extensions,
int len)
{
size_t i;
for (i = 0; i < SBI_HART_EXT_MAX; i++) {
if (fdt_stringlist_contains(isa, len, sbi_hart_ext[i].name))
__set_bit(sbi_hart_ext[i].id, extensions);
}
}
static int fdt_parse_isa_all_harts(void *fdt)
{
u32 hartid;
@@ -434,10 +446,6 @@ static int fdt_parse_isa_all_harts(void *fdt)
if (!fdt_node_is_enabled(fdt, cpu_offset))
continue;
val = fdt_getprop(fdt, cpu_offset, "riscv,isa", &len);
if (!val || len <= 0)
return SBI_ENOENT;
scratch = sbi_hartid_to_scratch(hartid);
if (!scratch)
return SBI_ENOENT;
@@ -445,6 +453,17 @@ static int fdt_parse_isa_all_harts(void *fdt)
hart_exts = sbi_scratch_offset_ptr(scratch,
fdt_isa_bitmap_offset);
val = fdt_getprop(fdt, cpu_offset, "riscv,isa-extensions", &len);
if (val && len > 0) {
fdt_parse_isa_extensions_one_hart((const char *)val,
hart_exts, len);
continue;
}
val = fdt_getprop(fdt, cpu_offset, "riscv,isa", &len);
if (!val || len <= 0)
return SBI_ENOENT;
err = fdt_parse_isa_one_hart((const char *)val, hart_exts);
if (err)
return err;