[PATCH v2 -next 2/4] RISC-V: ACPI: RHCT: Add function to get CBO block sizes

[Sunil V L <sunilvl@ventanamicro.com>]

Cache Block Operation (CBO) related block size in ACPI is provided by RHCT.
Add support to read the CMO node in RHCT to get this information.

Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
---
 arch/riscv/include/asm/acpi.h |  9 +++++
 drivers/acpi/riscv/rhct.c     | 72 ++++++++++++++++++++++++++++++++++-
 2 files changed, 80 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/include/asm/acpi.h b/arch/riscv/include/asm/acpi.h
index d5604d2073bc..0c4e8b35103e 100644
--- a/arch/riscv/include/asm/acpi.h
+++ b/arch/riscv/include/asm/acpi.h
@@ -66,6 +66,8 @@ int acpi_get_riscv_isa(struct acpi_table_header *table,
 		       unsigned int cpu, const char **isa);
 
 static inline int acpi_numa_get_nid(unsigned int cpu) { return NUMA_NO_NODE; }
+int acpi_get_cbo_block_size(struct acpi_table_header *table, unsigned int cpu, u32 *cbom_size,
+			    u32 *cboz_size, u32 *cbop_size);
 #else
 static inline void acpi_init_rintc_map(void) { }
 static inline struct acpi_madt_rintc *acpi_cpu_get_madt_rintc(int cpu)
@@ -79,6 +81,13 @@ static inline int acpi_get_riscv_isa(struct acpi_table_header *table,
 	return -EINVAL;
 }
 
+static inline int acpi_get_cbo_block_size(struct acpi_table_header *table,
+					  unsigned int cpu, u32 *cbom_size,
+					  u32 *cboz_size, u32 *cbop_size)
+{
+	return -EINVAL;
+}
+
 #endif /* CONFIG_ACPI */
 
 #endif /*_ASM_ACPI_H*/
diff --git a/drivers/acpi/riscv/rhct.c b/drivers/acpi/riscv/rhct.c
index b280b3e9c7d9..9042949277f8 100644
--- a/drivers/acpi/riscv/rhct.c
+++ b/drivers/acpi/riscv/rhct.c
@@ -8,6 +8,7 @@
 #define pr_fmt(fmt)     "ACPI: RHCT: " fmt
 
 #include <linux/acpi.h>
+#include <linux/bits.h>
 
 static struct acpi_table_header *acpi_get_rhct(void)
 {
@@ -56,7 +57,6 @@ int acpi_get_riscv_isa(struct acpi_table_header *table, unsigned int cpu, const
 	}
 
 	end = ACPI_ADD_PTR(struct acpi_rhct_node_header, rhct, rhct->header.length);
-
 	for (node = ACPI_ADD_PTR(struct acpi_rhct_node_header, rhct, rhct->node_offset);
 	     node < end;
 	     node = ACPI_ADD_PTR(struct acpi_rhct_node_header, node, node->length)) {
@@ -81,3 +81,73 @@ int acpi_get_riscv_isa(struct acpi_table_header *table, unsigned int cpu, const
 
 	return -1;
 }
+
+/*
+ * During early boot, the caller should call acpi_get_table() and pass its pointer to
+ * these functions(and free up later). At run time, since this table can be used
+ * multiple times, pass NULL so that the table remains in memory
+ */
+int acpi_get_cbo_block_size(struct acpi_table_header *table, unsigned int cpu,
+			    u32 *cbom_size, u32 *cboz_size, u32 *cbop_size)
+{
+	struct acpi_rhct_node_header *node, *ref_node, *end;
+	u32 size_hdr = sizeof(struct acpi_rhct_node_header);
+	u32 size_hartinfo = sizeof(struct acpi_rhct_hart_info);
+	struct acpi_rhct_hart_info *hart_info;
+	struct acpi_rhct_cmo_node *cmo_node;
+	struct acpi_table_rhct *rhct;
+	u32 *hart_info_node_offset;
+	u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
+
+	BUG_ON(acpi_disabled);
+
+	if (table) {
+		rhct = (struct acpi_table_rhct *)table;
+	} else {
+		rhct = (struct acpi_table_rhct *)acpi_get_rhct();
+		if (!rhct)
+			return -ENOENT;
+	}
+
+	end = ACPI_ADD_PTR(struct acpi_rhct_node_header, rhct, rhct->header.length);
+	for (node = ACPI_ADD_PTR(struct acpi_rhct_node_header, rhct, rhct->node_offset);
+	     node < end;
+	     node = ACPI_ADD_PTR(struct acpi_rhct_node_header, node, node->length)) {
+		if (node->type == ACPI_RHCT_NODE_TYPE_HART_INFO) {
+			hart_info = ACPI_ADD_PTR(struct acpi_rhct_hart_info, node, size_hdr);
+			hart_info_node_offset = ACPI_ADD_PTR(u32, hart_info, size_hartinfo);
+			if (acpi_cpu_id != hart_info->uid)
+				continue;
+
+			for (int i = 0; i < hart_info->num_offsets; i++) {
+				ref_node = ACPI_ADD_PTR(struct acpi_rhct_node_header,
+							rhct, hart_info_node_offset[i]);
+				if (ref_node->type == ACPI_RHCT_NODE_TYPE_CMO) {
+					cmo_node = ACPI_ADD_PTR(struct acpi_rhct_cmo_node,
+								ref_node, size_hdr);
+					if (cbom_size && cmo_node->cbom_size <= 30)
+						*cbom_size = BIT(cmo_node->cbom_size);
+
+					if (cboz_size && cmo_node->cboz_size <= 30)
+						*cboz_size = BIT(cmo_node->cboz_size);
+
+					if (cbop_size && cmo_node->cbop_size <= 30)
+						*cbop_size = BIT(cmo_node->cbop_size);
+
+					return 0;
+				}
+			}
+		}
+	}
+
+	if (cbom_size)
+		*cbom_size = 0;
+
+	if (cboz_size)
+		*cboz_size = 0;
+
+	if (cbop_size)
+		*cbop_size = 0;
+
+	return -ENOENT;
+}
-- 
2.39.2