[PATCH v3 3/9] lib: fdt_domain: parse domain WID properties

[Yu-Chien Peter Lin]

Add wid and widdeleg fields to struct sbi_domain to store the
RISC-V Worlds mlwid and mwideleg CSR values for each domain.
Also, parse the root and user-defined domains' WID during
fdt_domains_populate().

When Smlwid is implemented, the "wid" property is mandatory
for all domains; fail domain population if it is missing.

Signed-off-by: Yu-Chien Peter Lin <peter.lin at sifive.com>
---
Change v2->v3:
- Add validate_domain_wid() to check if 'wid' is specified when Smlwid
  extension is present; return SBI_EINVAL if missing.
- Parse 'wid' and 'widdeleg' for the root domain via fdt_parse_root_domain().
- Set root.widdeleg default to 0.
---
 include/sbi/sbi_domain.h   |  6 +++
 lib/sbi/sbi_domain.c       |  2 +
 lib/utils/fdt/fdt_domain.c | 84 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 92 insertions(+)

diff --git a/include/sbi/sbi_domain.h b/include/sbi/sbi_domain.h
index 56a21397..5a291d1f 100644
--- a/include/sbi/sbi_domain.h
+++ b/include/sbi/sbi_domain.h
@@ -19,6 +19,8 @@
 
 struct sbi_scratch;
 
+#define INVALID_WID	((unsigned int)~0U)
+
 /** Domain access types */
 enum sbi_domain_access {
 	SBI_DOMAIN_READ = (1UL << 0),
@@ -218,6 +220,10 @@ struct sbi_domain {
 	bool system_reset_allowed;
 	/** Is domain allowed to suspend the system */
 	bool system_suspend_allowed;
+	/** World ID for this domain (mlwid value) */
+	u32 wid;
+	/** World ID delegation bitmask for this domain (mwiddeleg value) */
+	u64 widdeleg;
 	/** Identifies whether to include the firmware region */
 	bool fw_region_inited;
 };
diff --git a/lib/sbi/sbi_domain.c b/lib/sbi/sbi_domain.c
index 42fe5632..be9020d0 100644
--- a/lib/sbi/sbi_domain.c
+++ b/lib/sbi/sbi_domain.c
@@ -30,6 +30,8 @@ struct sbi_domain root = {
 	.possible_harts = NULL,
 	.system_reset_allowed = true,
 	.system_suspend_allowed = true,
+	.wid = INVALID_WID,
+	.widdeleg = 0,
 	.fw_region_inited = false,
 };
 
diff --git a/lib/utils/fdt/fdt_domain.c b/lib/utils/fdt/fdt_domain.c
index e4cce8c3..8ce03236 100644
--- a/lib/utils/fdt/fdt_domain.c
+++ b/lib/utils/fdt/fdt_domain.c
@@ -13,6 +13,7 @@
 #include <sbi/sbi_console.h>
 #include <sbi/sbi_domain.h>
 #include <sbi/sbi_error.h>
+#include <sbi/sbi_hart.h>
 #include <sbi/sbi_hartmask.h>
 #include <sbi/sbi_heap.h>
 #include <sbi/sbi_scratch.h>
@@ -290,6 +291,42 @@ static int __fdt_parse_region(const void *fdt, int domain_offset,
 	return 0;
 }
 
+static void fdt_parse_domain_wid_props(const void *fdt, int offset,
+				       struct sbi_domain *dom)
+{
+	const fdt32_t *val;
+	int len;
+	u64 val64;
+
+	val = fdt_getprop(fdt, offset, "wid", &len);
+	if (val && len == sizeof(fdt32_t)) {
+		dom->wid = fdt32_to_cpu(val[0]);
+	}
+
+	val = fdt_getprop(fdt, offset, "widdeleg", &len);
+	if (val && (len == (2 * sizeof(fdt32_t)))) {
+		val64 = fdt32_to_cpu(val[0]);
+		val64 = (val64 << 32) | fdt32_to_cpu(val[1]);
+		dom->widdeleg = val64;
+	}
+}
+
+static int validate_domain_wid(const struct sbi_domain *dom)
+{
+	if (dom->wid != INVALID_WID)
+		return 0;
+
+	if (sbi_hart_has_extension(sbi_scratch_thishart_ptr(),
+				   SBI_HART_EXT_SMLWID)) {
+		sbi_printf("%s: domain \"%s\": missing \"wid\""
+			   " property (required by Smlwid)\n",
+			   __func__, dom->name);
+		return SBI_EINVAL;
+	}
+
+	return 0;
+}
+
 static int __fdt_parse_domain(const void *fdt, int domain_offset, void *opaque)
 {
 	u32 val32;
@@ -306,6 +343,7 @@ static int __fdt_parse_domain(const void *fdt, int domain_offset, void *opaque)
 	dom = sbi_zalloc(sizeof(*dom));
 	if (!dom)
 		return SBI_ENOMEM;
+	dom->wid = INVALID_WID;
 
 	preg.dom = dom;
 	preg.region_count = 0;
@@ -449,6 +487,12 @@ static int __fdt_parse_domain(const void *fdt, int domain_offset, void *opaque)
 	}
 	dom->next_mode = val32;
 
+	/* Read "wid" and "widdeleg" DT properties */
+	fdt_parse_domain_wid_props(fdt, domain_offset, dom);
+	err = validate_domain_wid(dom);
+	if (err)
+		goto fail_free_all;
+
 	/* Read "system-reset-allowed" DT property */
 	if (fdt_get_property(fdt, domain_offset,
 			     "system-reset-allowed", NULL))
@@ -477,12 +521,52 @@ fail_free_domain:
 	return err;
 }
 
+static int fdt_root_domain_offset(const void *fdt)
+{
+	int offset;
+
+	offset = fdt_path_offset(fdt, "/chosen");
+	if (offset < 0)
+		return offset;
+
+	offset = fdt_node_offset_by_compatible(fdt, offset,
+					       "opensbi,domain,config");
+	if (offset < 0)
+		return offset;
+
+	return fdt_subnode_offset(fdt, offset, "root");
+}
+
+static int fdt_parse_root_domain(const void *fdt)
+{
+	int offset;
+
+	if (fdt) {
+		offset = fdt_root_domain_offset(fdt);
+		if (offset >= 0)
+			fdt_parse_domain_wid_props(fdt, offset, &root);
+	}
+
+	/*
+	 * Ensure root domain has a valid WID
+	 * even if FDT or root subnode is absent
+	 */
+	return validate_domain_wid(&root);
+}
+
 int fdt_domains_populate(const void *fdt)
 {
+	int err;
+
 	/* Sanity checks */
 	if (!fdt)
 		return SBI_EINVAL;
 
+	/* Parse root domain config from "root" subnode */
+	err = fdt_parse_root_domain(fdt);
+	if (err)
+		return err;
+
 	/* Iterate over each domain in FDT and populate details */
 	return fdt_iterate_each_domain_ro(fdt, NULL, __fdt_parse_domain);
 }
-- 
2.43.7