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

[Atish Patra]

On 8/2/18 4:50 AM, Christoph Hellwig wrote:
From: Palmer Dabbelt <pal...@sifive.com>
Follow the updated DT specs and read the timebase-frequency from the
CPU 0 node.


However, the DT in the HighFive Unleashed has the entry at the wrong place.

Even the example in github also at wrong place.
https://github.com/riscv/riscv-device-tree-doc/pull/8/commits/2461d481329c55005fcbe684f0d6bdb3b7f0a432

DT should be consistent between Documentation and the one in the 
hardware. I can fix them in bbl & submit a bbl patch. But I am not sure 
if that's an acceptable way to do it.

Regards,
Atish
Signed-off-by: Palmer Dabbelt <pal...@dabbelt.com>
[hch: updated changelog]
Signed-off-by: Christoph Hellwig <h...@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();
  }