[PATCH v2 4/5] lib: utils/cache: Add fdt cmo helpers

[Nick Hu]

Add the helpers to build up the cache hierarchy via FDT and provide some
cmo functions for the user who want to flush the entire cache.

Signed-off-by: Nick Hu <nick.hu at sifive.com>
Reviewed-by: Samuel Holland <samuel.holland at sifive.com>
---
 include/sbi_utils/cache/fdt_cmo_helper.h |  34 +++++++
 lib/utils/cache/fdt_cmo_helper.c         | 112 +++++++++++++++++++++++
 lib/utils/cache/objects.mk               |   1 +
 3 files changed, 147 insertions(+)
 create mode 100644 include/sbi_utils/cache/fdt_cmo_helper.h
 create mode 100644 lib/utils/cache/fdt_cmo_helper.c

diff --git a/include/sbi_utils/cache/fdt_cmo_helper.h b/include/sbi_utils/cache/fdt_cmo_helper.h
new file mode 100644
index 00000000..4275725e
--- /dev/null
+++ b/include/sbi_utils/cache/fdt_cmo_helper.h
@@ -0,0 +1,34 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2025 SiFive Inc.
+ */
+
+#ifndef __FDT_CMO_HELPER_H__
+#define __FDT_CMO_HELPER_H__
+
+/**
+ * Flush the private first level cache of the current hart
+ *
+ * @return 0 on success, or a negative error code on failure
+ */
+int fdt_cmo_private_flc_flush_all(void);
+
+/**
+ * Flush the last level cache of the current hart
+ *
+ * @return 0 on success, or a negative error code on failure
+ */
+int fdt_cmo_llc_flush_all(void);
+
+/**
+ * Initialize the cache devices for each hart
+ *
+ * @param fdt devicetree blob
+ * @param cold_boot cold init or warm init
+ *
+ * @return 0 on success, or a negative error code on failure
+ */
+int fdt_cmo_init(bool cold_boot);
+
+#endif
diff --git a/lib/utils/cache/fdt_cmo_helper.c b/lib/utils/cache/fdt_cmo_helper.c
new file mode 100644
index 00000000..6d2e853d
--- /dev/null
+++ b/lib/utils/cache/fdt_cmo_helper.c
@@ -0,0 +1,112 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2025 SiFive Inc.
+ */
+
+#include <libfdt.h>
+#include <sbi/sbi_error.h>
+#include <sbi/sbi_scratch.h>
+#include <sbi_utils/cache/fdt_cache.h>
+#include <sbi_utils/cache/fdt_cmo_helper.h>
+#include <sbi_utils/fdt/fdt_helper.h>
+
+static unsigned long flc_offset;
+
+#define get_hart_flc(_s) \
+	sbi_scratch_read_type(_s, struct cache_device *, flc_offset)
+#define set_hart_flc(_s, _p) \
+	sbi_scratch_write_type(_s, struct cache_device *, flc_offset, _p)
+
+int fdt_cmo_private_flc_flush_all(void)
+{
+	struct cache_device *flc = get_hart_flc(sbi_scratch_thishart_ptr());
+
+	if (!flc || !flc->cpu_private)
+		return SBI_ENODEV;
+
+	return cache_flush_all(flc);
+}
+
+int fdt_cmo_llc_flush_all(void)
+{
+	struct cache_device *llc = get_hart_flc(sbi_scratch_thishart_ptr());
+
+	if (!llc)
+		return SBI_ENODEV;
+
+	while (llc->next)
+		llc = llc->next;
+
+	return cache_flush_all(llc);
+}
+
+static int fdt_cmo_cold_init(const void *fdt)
+{
+	struct sbi_scratch *scratch;
+	struct cache_device *dev;
+	int cpu_offset, cpus_offset, rc;
+	u32 hartid;
+
+	cpus_offset = fdt_path_offset(fdt, "/cpus");
+	if (cpus_offset < 0)
+		return SBI_EINVAL;
+
+	fdt_for_each_subnode(cpu_offset, fdt, cpus_offset) {
+		rc = fdt_parse_hart_id(fdt, cpu_offset, &hartid);
+		if (rc)
+			continue;
+
+		scratch = sbi_hartid_to_scratch(hartid);
+		if (!scratch)
+			continue;
+
+		rc = fdt_next_cache_get(fdt, cpu_offset, &dev);
+		if (rc)
+			return rc;
+
+		set_hart_flc(scratch, dev);
+	}
+
+	return SBI_OK;
+}
+
+static int fdt_cmo_warm_init(void)
+{
+	struct cache_device *cur = get_hart_flc(sbi_scratch_thishart_ptr());
+	int rc;
+
+	while (cur) {
+		if (cur->ops && cur->ops->warm_init) {
+			rc = cur->ops->warm_init(cur);
+			if (rc)
+				return rc;
+		}
+
+		cur = cur->next;
+	}
+
+	return SBI_OK;
+}
+
+int fdt_cmo_init(bool cold_boot)
+{
+	const void *fdt = fdt_get_address();
+	int rc;
+
+	if (cold_boot) {
+		flc_offset = sbi_scratch_alloc_type_offset(struct cache_device *);
+		if (!flc_offset)
+			return SBI_ENOMEM;
+
+		rc = fdt_cmo_cold_init(fdt);
+		if (rc)
+			return rc;
+	}
+
+	rc = fdt_cmo_warm_init();
+	if (rc)
+		return rc;
+
+	return SBI_OK;
+}
diff --git a/lib/utils/cache/objects.mk b/lib/utils/cache/objects.mk
index a343eb8c..6829a966 100644
--- a/lib/utils/cache/objects.mk
+++ b/lib/utils/cache/objects.mk
@@ -6,6 +6,7 @@
 
 libsbiutils-objs-$(CONFIG_FDT_CACHE) += cache/fdt_cache.o
 libsbiutils-objs-$(CONFIG_FDT_CACHE) += cache/fdt_cache_drivers.carray.o
+libsbiutils-objs-$(CONFIG_FDT_CACHE) += cache/fdt_cmo_helper.o
 
 carray-fdt_cache_drivers-$(CONFIG_FDT_CACHE_SIFIVE_CCACHE) += fdt_sifive_ccache
 libsbiutils-objs-$(CONFIG_FDT_CACHE_SIFIVE_CCACHE) += cache/fdt_sifive_ccache.o
-- 
2.17.1