diff mbox series

[v2,1/2] riscv: Try to get cpu frequency from device tree

Message ID bbd7469b-d1de-8da7-71a0-3590a0e892c0@gmail.com
State Superseded
Delegated to: Andes
Headers show
Series [v2,1/2] riscv: Try to get cpu frequency from device tree | expand

Commit Message

Sean Anderson Feb. 2, 2020, 5:38 p.m. UTC
Instead of always using the "clock-frequency" property to determine cpu
frequency, try using a clock in "clocks" if it exists. This patch also fixes a
bug where there could be spurious higher frequencies if sizeof(u32) !=
sizeof(ulong).

Signed-off-by: Sean Anderson <seanga2@gmail.com>
---
  This patch is the combination of the patches
  https://patchwork.ozlabs.org/patch/1223933/
  https://patchwork.ozlabs.org/patch/1224957/
  "riscv: Fix incorrect cpu frequency on RV64"
  "riscv: Try to get cpu frequency from device tree"

  Changes for v2:
  - Renamed err to ret
 drivers/cpu/riscv_cpu.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

Comments

Bin Meng Feb. 4, 2020, 10:36 a.m. UTC | #1
On Mon, Feb 3, 2020 at 1:38 AM Sean Anderson <seanga2@gmail.com> wrote:
>
> Instead of always using the "clock-frequency" property to determine cpu
> frequency, try using a clock in "clocks" if it exists. This patch also fixes a
> bug where there could be spurious higher frequencies if sizeof(u32) !=
> sizeof(ulong).
>
> Signed-off-by: Sean Anderson <seanga2@gmail.com>
> ---
>   This patch is the combination of the patches
>   https://patchwork.ozlabs.org/patch/1223933/
>   https://patchwork.ozlabs.org/patch/1224957/
>   "riscv: Fix incorrect cpu frequency on RV64"
>   "riscv: Try to get cpu frequency from device tree"
>
>   Changes for v2:
>   - Renamed err to ret
>  drivers/cpu/riscv_cpu.c | 18 +++++++++++++++++-
>  1 file changed, 17 insertions(+), 1 deletion(-)
>

Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff mbox series

Patch

diff --git a/drivers/cpu/riscv_cpu.c b/drivers/cpu/riscv_cpu.c
index 28ad0aa30f..5309a49e60 100644
--- a/drivers/cpu/riscv_cpu.c
+++ b/drivers/cpu/riscv_cpu.c
@@ -3,6 +3,7 @@ 
  * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
  */
 
+#include <clk.h>
 #include <common.h>
 #include <cpu.h>
 #include <dm.h>
@@ -27,9 +28,24 @@  static int riscv_cpu_get_desc(struct udevice *dev, char *buf, int size)
 
 static int riscv_cpu_get_info(struct udevice *dev, struct cpu_info *info)
 {
+	int ret;
+	struct clk clk;
 	const char *mmu;
 
-	dev_read_u32(dev, "clock-frequency", (u32 *)&info->cpu_freq);
+	/* Zero out the frequency, in case sizeof(ulong) != sizeof(u32) */
+	info->cpu_freq = 0;
+
+	/* First try getting the frequency from the assigned clock */
+	ret = clk_get_by_index(dev, 0, &clk);
+	if (!ret) {
+		ret = clk_get_rate(&clk);
+		if (!IS_ERR_VALUE(ret))
+			info->cpu_freq = ret;
+		clk_free(&clk);
+	}
+
+	if (!info->cpu_freq)
+		dev_read_u32(dev, "clock-frequency", (u32 *)&info->cpu_freq);
 
 	mmu = dev_read_string(dev, "mmu-type");
 	if (!mmu)