From: Parth Pancholi <parth.panch...@toradex.com>
AM62x devices now support CPU throttling based on thermal alerts
with a Linux commit 10e7bfd8114c ("arm64: dts: ti: k3-am62: Enable
CPU freq throttling on thermal alert"). However, this functionality
does not work correctly across all variants of the AM62x SoCs
which have different numbers of Cortex-A CPU cores: AM62x1 (1 core),
AM62x2 (2 cores), and AM62x4 (4 cores). On single-core and dual-core
AM62x devices, the following error is observed in the Linux kernel:
OF: /thermal-zones/main0-thermal/cooling-maps/map0: could not find
phandle 94
OF: /thermal-zones/main1-thermal/cooling-maps/map0: could not find
phandle 94
This commit adds a fixup to dynamically adjust the cooling-device
nodes in the thermal zones based on the actual number of CPU cores
available. This resolves the issue of CPU throttling not working
correctly on single-core and dual-core AM62x devices, while
maintaining the functionality for AM62x quad-core devices.
A similar approach is implemented for example on i.MX8MM SoC.
Signed-off-by: Parth Pancholi <parth.panch...@toradex.com>
---
arch/arm/mach-k3/am62x/am625_fdt.c | 36 ++++++++++++++++++++++++++++++
1 file changed, 36 insertions(+)
diff --git a/arch/arm/mach-k3/am62x/am625_fdt.c
b/arch/arm/mach-k3/am62x/am625_fdt.c
index 8fe200a42318..ab9b573f3cff 100644
--- a/arch/arm/mach-k3/am62x/am625_fdt.c
+++ b/arch/arm/mach-k3/am62x/am625_fdt.c
@@ -5,6 +5,7 @@
#include <asm/hardware.h>
#include <fdt_support.h>
+#include <fdtdec.h>
#include "../common_fdt.h"
@@ -75,12 +76,47 @@ static void fdt_fixup_thermal_zone_nodes_am625(void *blob,
int maxc)
}
}
+static void fdt_fixup_thermal_cooling_device_cpus_am625(void *blob, int
core_nr)
+{
+ static const char * const thermal_path[] = {
+ "/thermal-zones/main0-thermal/cooling-maps/map0",
+ "/thermal-zones/main1-thermal/cooling-maps/map0"
+ };
+
+ int node, cnt, i, ret;
+ u32 cooling_dev[12];
+
+ for (i = 0; i < ARRAY_SIZE(thermal_path); i++) {
+ int new_count = core_nr * 3; /* Each CPU has 3 entries */
+ int j;
+
+ node = fdt_path_offset(blob, thermal_path[i]);
+ if (node < 0)
+ continue; /* Not found, skip it */
+
+ cnt = fdtdec_get_int_array_count(blob, node, "cooling-device",
+ cooling_dev,
ARRAY_SIZE(cooling_dev));
+ if (cnt < 0)
+ continue;
+
+ for (j = 0; j < new_count; j++)
+ cooling_dev[j] = cpu_to_fdt32(cooling_dev[j]);
+
+ ret = fdt_setprop(blob, node, "cooling-device", cooling_dev,
+ new_count * sizeof(u32));
+ if (ret < 0)
+ printf("Error %s, cooling-device setprop failed %d\n",
+ thermal_path[i], ret);
+ }
+}
+
int ft_system_setup(void *blob, struct bd_info *bd)
{
fdt_fixup_cores_nodes_am625(blob, k3_get_core_nr());
fdt_fixup_gpu_nodes_am625(blob, k3_has_gpu());
fdt_fixup_pru_node_am625(blob, k3_has_pru());
fdt_fixup_thermal_zone_nodes_am625(blob, k3_get_max_temp());
+ fdt_fixup_thermal_cooling_device_cpus_am625(blob, k3_get_core_nr());
fdt_fixup_reserved(blob, "tfa", CONFIG_K3_ATF_LOAD_ADDR, 0x80000);
fdt_fixup_reserved(blob, "optee", CONFIG_K3_OPTEE_LOAD_ADDR, 0x1800000);
--
2.34.1
