Re: [PATCH 3/3] arm: mach-k3: am62a: Fixup a53 max cpu frequency by speed-grade

[Daniel Schultz]

On 4/30/25 12:42, Aparna Patra wrote:
AM62A SoC has multiple speed grades. Add function to delete
non-relevant CPU frequency nodes, based on the information
retrieved from hardware registers. Fastest grade's maximum
frequency also depends on PMIC voltage,hence to simplify
implementation use the smaller value.

Signed-off-by: Aparna Patra <a-pa...@ti.com>
---
  arch/arm/mach-k3/am62ax/am62a7_fdt.c          | 14 +++++++++++
  .../arm/mach-k3/include/mach/am62a_hardware.h | 23 +++++++++++++++++++
  2 files changed, 37 insertions(+)

diff --git a/arch/arm/mach-k3/am62ax/am62a7_fdt.c 
b/arch/arm/mach-k3/am62ax/am62a7_fdt.c
index 40833ca392..9526c5b255 100644
--- a/arch/arm/mach-k3/am62ax/am62a7_fdt.c
+++ b/arch/arm/mach-k3/am62ax/am62a7_fdt.c
@@ -81,6 +81,19 @@ static void fdt_fixup_thermal_zone_nodes_am62a(void *blob, 
int maxc)
        }
  }
  
+static void fdt_fixup_cpu_freq_nodes_am62a(void *blob, int max_freq)
+{
+       if (max_freq >= 1250000000)
+               return;
I dont think this if case is required. Just let if fail both following 
conditions.
+       if (max_freq <= 1000000000) {
+               fdt_del_node_path(blob, "/opp-table/opp-1250000000");
+               fdt_del_node_path(blob, "/opp-table/opp-1400000000");
+       }
+       if (max_freq <= 800000000) {
+               fdt_del_node_path(blob, "/opp-table/opp-1000000000");
+       }
+}
+
  int ft_system_setup(void *blob, struct bd_info *bd)
  {
        fdt_fixup_cores_wdt_nodes_am62a(blob, k3_get_core_nr());
@@ -88,6 +101,7 @@ int ft_system_setup(void *blob, struct bd_info *bd)
        fdt_fixup_video_codec_nodes_am62a(blob, k3_has_video_codec());
        fdt_fixup_canfd_nodes_am62a(blob, k3_has_canfd());
        fdt_fixup_thermal_zone_nodes_am62a(blob, k3_get_max_temp());
+       fdt_fixup_cpu_freq_nodes_am62a(blob, k3_get_a53_max_frequency());
        fdt_fixup_reserved(blob, "tfa", CONFIG_K3_ATF_LOAD_ADDR, 0x80000);
        fdt_fixup_reserved(blob, "optee", CONFIG_K3_OPTEE_LOAD_ADDR, 0x1800000);
  
diff --git a/arch/arm/mach-k3/include/mach/am62a_hardware.h b/arch/arm/mach-k3/include/mach/am62a_hardware.h
index 0ec04a72f5..64e4a379fa 100644
--- a/arch/arm/mach-k3/include/mach/am62a_hardware.h
+++ b/arch/arm/mach-k3/include/mach/am62a_hardware.h
@@ -28,6 +28,8 @@
  #define JTAG_DEV_VIDEO_CODEC_SHIFT                    14
  #define JTAG_DEV_DSS_MASK                     GENMASK(16, 13)
  #define JTAG_DEV_DSS_SHIFT                    13
+#define JTAG_DEV_SPEED_MASK                    GENMASK(10, 6)
+#define JTAG_DEV_SPEED_SHIFT                   6
  #define JTAG_DEV_TEMP_MASK                    GENMASK(5, 3)
  #define JTAG_DEV_TEMP_SHIFT                   3
  
@@ -144,6 +146,27 @@ static inline int k3_get_max_temp(void)
                return JTAG_DEV_TEMP_EXTENDED_VALUE;
  }
  
+static inline char k3_get_speed_grade(void)
+{
+       u32 dev_id = readl(CTRLMMR_WKUP_JTAG_DEVICE_ID);
+       u32 speed_grade = (dev_id & JTAG_DEV_SPEED_MASK) >>
+                          JTAG_DEV_SPEED_SHIFT;
+
+       return 'A' - 1 + speed_grade;
+}
+
+static inline int k3_get_a53_max_frequency(void)
+{
+       if (k3_get_speed_grade() <= 'N')
+               return 800000000;
+

^ empty lines where should be none in this function.

- Daniel

+       else if (k3_get_speed_grade() <= 'R')
+               return 1000000000;
+
+       else
+               return 1250000000;
+}
+
  #if defined(CONFIG_SYS_K3_SPL_ATF) && !defined(__ASSEMBLY__)
  
  static const u32 put_device_ids[] = {};