[PATCH 09/11] RISC-V: Support per-hart timebase-frequency

[Christoph Hellwig <hch@lst.de>]

From: Palmer Dabbelt <palmer@sifive.com>

Follow the updated DT specs and read the timebase-frequency from the
CPU 0 node.

Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
[hch: updated changelog]
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/riscv/kernel/time.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/arch/riscv/kernel/time.c b/arch/riscv/kernel/time.c
index 0df9b2cbd645..1bb01dc2d0f1 100644
--- a/arch/riscv/kernel/time.c
+++ b/arch/riscv/kernel/time.c
@@ -24,17 +24,24 @@ void __init init_clockevent(void)
 	csr_set(sie, SIE_STIE);
 }
 
-void __init time_init(void)
+static long __init timebase_frequency(void)
 {
 	struct device_node *cpu;
 	u32 prop;
 
 	cpu = of_find_node_by_path("/cpus");
-	if (!cpu || of_property_read_u32(cpu, "timebase-frequency", &prop))
-		panic(KERN_WARNING "RISC-V system with no 'timebase-frequency' in DTS\n");
-	riscv_timebase = prop;
+	if (cpu && !of_property_read_u32(cpu, "timebase-frequency", &prop))
+		return prop;
+	cpu = of_find_node_by_path("/cpus/cpu@0");
+	if (cpu && !of_property_read_u32(cpu, "timebase-frequency", &prop))
+		return prop;
 
-	lpj_fine = riscv_timebase / HZ;
+	panic(KERN_WARNING "RISC-V system with no 'timebase-frequency' in DTS\n");
+}
 
+void __init time_init(void)
+{
+	riscv_timebase = timebase_frequency();
+	lpj_fine = riscv_timebase / HZ;
 	init_clockevent();
 }
-- 
2.18.0