[RFC PATCH 02/12] lib: utils: fdt_helper: parse RISC-V Worlds DT properties

[Yu-Chien Peter Lin]

Add fdt_parse_worlds_all_harts() to parse RISC-V Worlds device tree
properties from CPU nodes:
  - riscv,pmwid (u32): Physical Machine World ID for this hart
  - riscv,pmwidlist (u64): Bitmap of permitted M-mode World IDs
  - riscv,pmlwidlist (u64): Bitmap of permitted S/U-mode World IDs

This patch extends the sbi_hart_features struct with new fields to
store the parsed World ID configuration (has_pmwid, pmwid, pmwidlist,
and pmlwidlist).

Link: https://lore.kernel.org/all/20260619105834.1277302-3-peter.lin@sifive.com/
Signed-off-by: Yu-Chien Peter Lin <peter.lin at sifive.com>
---
 include/sbi/sbi_hart.h             | 15 ++++++++
 include/sbi_utils/fdt/fdt_helper.h |  2 +
 lib/utils/fdt/fdt_helper.c         | 61 ++++++++++++++++++++++++++++++
 platform/generic/platform.c        | 13 ++++++-
 4 files changed, 90 insertions(+), 1 deletion(-)

diff --git a/include/sbi/sbi_hart.h b/include/sbi/sbi_hart.h
index 2941809e..97072c09 100644
--- a/include/sbi/sbi_hart.h
+++ b/include/sbi/sbi_hart.h
@@ -135,6 +135,21 @@ struct sbi_hart_features {
 	unsigned int pmp_log2gran;
 	unsigned int mhpm_mask;
 	unsigned int mhpm_bits;
+	/** True if riscv,pmwid was present in DT */
+	bool has_pmwid;
+	u32 pmwid;
+	/**
+	 * Platform-defined bitmap of M-mode WIDs
+	 * (from DT riscv,pmwidlist). Zero means
+	 * absent/unrestricted.
+	 */
+	u64 pmwidlist;
+	/**
+	 * Platform-defined bitmap of S/U-mode WIDs
+	 * (from DT riscv,pmlwidlist). Zero means
+	 * absent/unrestricted.
+	 */
+	u64 pmlwidlist;
 };
 
 extern unsigned long hart_features_offset;
diff --git a/include/sbi_utils/fdt/fdt_helper.h b/include/sbi_utils/fdt/fdt_helper.h
index 75a564d1..3f3d091b 100644
--- a/include/sbi_utils/fdt/fdt_helper.h
+++ b/include/sbi_utils/fdt/fdt_helper.h
@@ -56,6 +56,8 @@ int fdt_parse_timebase_frequency(const void *fdt, unsigned long *freq);
 
 int fdt_parse_isa_extensions_all_harts(const void *fdt);
 
+int fdt_parse_worlds_all_harts(const void *fdt);
+
 int fdt_parse_gaisler_uart_node(const void *fdt, int nodeoffset,
 				struct platform_uart_data *uart);
 
diff --git a/lib/utils/fdt/fdt_helper.c b/lib/utils/fdt/fdt_helper.c
index ad4efaaf..8b40cd28 100644
--- a/lib/utils/fdt/fdt_helper.c
+++ b/lib/utils/fdt/fdt_helper.c
@@ -457,6 +457,67 @@ int fdt_parse_isa_extensions_all_harts(const void *fdt)
 	return 0;
 }
 
+int fdt_parse_worlds_all_harts(const void *fdt)
+{
+	u32 hartid;
+	const fdt32_t *val;
+	struct sbi_scratch *scratch;
+	struct sbi_hart_features *hfeatures;
+	int err, cpu_offset, cpus_offset, len;
+
+	if (!fdt)
+		return SBI_EINVAL;
+
+	cpus_offset = fdt_path_offset(fdt, "/cpus");
+	if (cpus_offset < 0)
+		return cpus_offset;
+
+	fdt_for_each_subnode(cpu_offset, fdt, cpus_offset) {
+		err = fdt_parse_hart_id(fdt, cpu_offset, &hartid);
+		if (err)
+			continue;
+
+		if (!fdt_node_is_enabled(fdt, cpu_offset))
+			continue;
+
+		scratch = sbi_hartid_to_scratch(hartid);
+		if (!scratch)
+			return SBI_ENOENT;
+
+		hfeatures = sbi_hart_features_ptr(scratch);
+		if (!hfeatures)
+			return SBI_ENOENT;
+
+		val = fdt_getprop(fdt, cpu_offset, "riscv,pmwid", &len);
+		if (val && len == sizeof(fdt32_t)) {
+			hfeatures->pmwid = fdt32_to_cpu(*val);
+			hfeatures->has_pmwid = true;
+		}
+
+		val = fdt_getprop(fdt, cpu_offset, "riscv,pmwidlist", &len);
+		if (val && len == 2 * sizeof(fdt32_t)) {
+			hfeatures->pmwidlist = ((u64)fdt32_to_cpu(val[0]) << 32) |
+					        fdt32_to_cpu(val[1]);
+		}
+
+		val = fdt_getprop(fdt, cpu_offset, "riscv,pmlwidlist", &len);
+		if (val && len == 2 * sizeof(fdt32_t)) {
+			hfeatures->pmlwidlist = ((u64)fdt32_to_cpu(val[0]) << 32) |
+					         fdt32_to_cpu(val[1]);
+		}
+
+		/* Sanity checks */
+		if (hfeatures->has_pmwid && (hfeatures->pmwid >= 64))
+			return SBI_EINVAL;
+		if (hfeatures->has_pmwid && hfeatures->pmwidlist &&
+		    !(hfeatures->pmwidlist & BIT_ULL(hfeatures->pmwid))) {
+			return SBI_EINVAL;
+		}
+	}
+
+	return 0;
+}
+
 static int fdt_parse_uart_node_common(const void *fdt, int nodeoffset,
 				      struct platform_uart_data *uart,
 				      unsigned long default_freq,
diff --git a/platform/generic/platform.c b/platform/generic/platform.c
index 1df0280d..51e9f342 100644
--- a/platform/generic/platform.c
+++ b/platform/generic/platform.c
@@ -255,11 +255,22 @@ int generic_final_init(bool cold_boot)
 
 int generic_extensions_init(bool cold_boot)
 {
+	int rc;
+
 	if (!cold_boot)
 		return 0;
 
 	/* Parse the ISA string from FDT and enable the listed extensions */
-	return fdt_parse_isa_extensions_all_harts(fdt_get_address());
+	rc = fdt_parse_isa_extensions_all_harts(fdt_get_address());
+	if (rc)
+		return rc;
+
+	/* Parse RISC-V Worlds CPU properties from FDT */
+	rc = fdt_parse_worlds_all_harts(fdt_get_address());
+	if (rc)
+		return rc;
+
+	return 0;
 }
 
 int generic_domains_init(void)
-- 
2.43.7