[PATCH v4 01/10] RISC-V: Add riscv_fw_parent_hartid() function

[Anup Patel <apatel@ventanamicro.com>]

We add common riscv_fw_parent_hartid() which help device drivers
to get parent hartid of the INTC (i.e. local interrupt controller)
fwnode. This should work for both DT and ACPI.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
---
 arch/riscv/include/asm/processor.h |  3 +++
 arch/riscv/kernel/cpu.c            | 16 ++++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/arch/riscv/include/asm/processor.h b/arch/riscv/include/asm/processor.h
index 94a0590c6971..6fb8bbec8459 100644
--- a/arch/riscv/include/asm/processor.h
+++ b/arch/riscv/include/asm/processor.h
@@ -77,6 +77,9 @@ struct device_node;
 int riscv_of_processor_hartid(struct device_node *node, unsigned long *hartid);
 int riscv_of_parent_hartid(struct device_node *node, unsigned long *hartid);
 
+struct fwnode_handle;
+int riscv_fw_parent_hartid(struct fwnode_handle *node, unsigned long *hartid);
+
 extern void riscv_fill_hwcap(void);
 extern int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src);
 
diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c
index 5de6fb703cc2..67b335789b22 100644
--- a/arch/riscv/kernel/cpu.c
+++ b/arch/riscv/kernel/cpu.c
@@ -73,6 +73,22 @@ int riscv_of_parent_hartid(struct device_node *node, unsigned long *hartid)
 	return -1;
 }
 
+/* Find hart ID of the CPU fwnode under which given fwnode falls. */
+int riscv_fw_parent_hartid(struct fwnode_handle *node, unsigned long *hartid)
+{
+	int rc;
+	u64 temp;
+
+	if (!is_of_node(node)) {
+		rc = fwnode_property_read_u64_array(node, "hartid", &temp, 1);
+		if (!rc)
+			*hartid = temp;
+	} else
+		rc = riscv_of_parent_hartid(to_of_node(node), hartid);
+
+	return rc;
+}
+
 DEFINE_PER_CPU(struct riscv_cpuinfo, riscv_cpuinfo);
 
 unsigned long riscv_cached_mvendorid(unsigned int cpu_id)
-- 
2.34.1