[PATCH v9 17/21] riscv: Try to get cpu frequency from a "clocks" node if it exists

Sean Anderson
2020-04-23T02:33:16Z

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>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
---
This patch was previously sumbitted on its own as
https://patchwork.ozlabs.org/patch/1232420/

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 in v5:
- Include linux/err.h explicitly
- Reword commit message

Changes in v4:
- New

drivers/cpu/riscv_cpu.c | 19 ++++++++++++++++++-
1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/drivers/cpu/riscv_cpu.c b/drivers/cpu/riscv_cpu.c
index 28ad0aa30f..c6ed060abc 100644
--- a/drivers/cpu/riscv_cpu.c
+++ b/drivers/cpu/riscv_cpu.c
@@ -3,12 +3,14 @@
* Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
*/

+#include <clk.h>
#include <common.h>
#include <cpu.h>
#include <dm.h>
#include <errno.h>
#include <dm/device-internal.h>
#include <dm/lists.h>
+#include <linux/err.h>

DECLARE_GLOBAL_DATA_PTR;

@@ -27,9 +29,24 @@ 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)
--
2.25.1