| Message ID | 20250309121324.29633-2-john.madieu.xa@bp.renesas.com (mailing list archive) |
|---|---|
| State | New |
| Delegated to: | Geert Uytterhoeven |
| Headers | show |
| Series | thermal: Add CPU hotplug cooling driver | expand |
On 09/03/2025 13:13, John Madieu wrote: > + > +/* Check if a trip point is of type "plug" */ > +static bool is_plug_trip_point(struct device_node *trip_node) > +{ > + const char *trip_type_str; > + > + if (!trip_node) { > + pr_err("Trip node is NULL\n"); > + return false; > + } > + > + if (of_property_read_string(trip_node, "type", &trip_type_str)) { > + pr_err("Trip node missing 'type' property\n"); > + return false; > + } > + > + pr_info("Trip type: '%s'\n", trip_type_str); > + > + if (strcmp(trip_type_str, "plug") != 0) { type is object, not string. Where is ABI documented? For the type and its value? > + pr_debug("Trip type is '%s', not 'plug' - skipping\n", > + trip_type_str); > + return false; > + } > + > + return true; > +} > + > +/* Init function */ > +static int __init cpu_hotplug_cooling_init(void) > +{ > + struct device_node *thermal_zones, *thermal_zone; > + int ret = 0; > + int count = 0; > + > + bitmap_zero(cpu_cooling_registered, NR_CPUS); > + > + thermal_zones = of_find_node_by_name(NULL, "thermal-zones"); > + if (!thermal_zones) { > + pr_err("Missing thermal-zones node\n"); > + return -EINVAL; > + } > + > + /* Process each thermal zone */ > + for_each_child_of_node(thermal_zones, thermal_zone) { > + struct device_node *trips, *trip; > + struct device_node *maps, *map; > + bool found_plug = false; > + > + /* First find trips and get a specific plug trip */ > + trips = of_find_node_by_name(thermal_zone, "trips"); > + if (!trips) > + continue; > + > + /* Find the emergency trip with type="plug" */ > + for_each_child_of_node(trips, trip) { > + if (is_plug_trip_point(trip)) { > + found_plug = true; > + break; > + } > + } > + > + /* If we didn't find a plug trip, no need to process this zone */ > + if (!found_plug) { > + of_node_put(trips); > + continue; > + } > + > + maps = of_find_node_by_name(thermal_zone, "cooling-maps"); > + if (!maps) { > + of_node_put(trip); > + of_node_put(trips); > + continue; > + } > + > + pr_info("Found 'plug' trip point, processing cooling devices\n"); dev_info, or just drop. You are not supposed to print successes of standard DT parsing. > + > + /* Find the specific cooling map that references our plug trip */ > + for_each_child_of_node(maps, map) { > + struct device_node *trip_ref; > + struct of_phandle_args cooling_spec; > + int idx = 0; > + > + trip_ref = of_parse_phandle(map, "trip", 0); > + if (!trip_ref || trip_ref != trip) { > + if (trip_ref) > + of_node_put(trip_ref); > + continue; > + } > + of_node_put(trip_ref); > + > + if (!of_find_property(map, "cooling-device", NULL)) { > + pr_err("Missing cooling-device property\n"); > + continue; > + } > + > + /* Iterate through all cooling-device entries */ > + while (of_parse_phandle_with_args( > + map, "cooling-device", > + "#cooling-cells", idx++, > + &cooling_spec) == 0) { > + struct device_node *cpu_node = cooling_spec.np; > + int cpu; > + > + if (!cpu_node) { > + pr_err("CPU node at index %d is NULL\n", > + idx - 1); > + continue; > + } > + > + cpu = of_cpu_node_to_id(cpu_node); > + if (cpu < 0) { > + pr_err("Failed to map CPU node %pOF to logical ID\n", > + cpu_node); > + of_node_put(cpu_node); > + continue; > + } > + > + if (cpu >= num_possible_cpus()) { > + pr_err("Invalid CPU ID %d (max %d)\n", > + cpu, num_possible_cpus() - 1); > + of_node_put(cpu_node); > + continue; > + } > + > + pr_info("Processing cooling device for CPU%d\n", cpu); > + ret = register_cpu_hotplug_cooling(cpu_node, cpu); > + if (ret == 0) > + count++; > + > + of_node_put(cpu_node); > + } > + break; /* Only process the first map that references our trip */ > + } > + of_node_put(maps); > + of_node_put(trip); > + of_node_put(trips); > + } > + of_node_put(thermal_zones); > + > + if (count == 0) { > + pr_err("No cooling devices registered\n"); > + return -ENODEV; > + } > + > + pr_info("CPU hotplug cooling driver initialized with %d devices\n", count); Drop. Why would you print this on MIPS machine which does not care about it, just because someone loaded a module? > + return 0; > +} > + > +/* Exit function */ > +static void __exit cpu_hotplug_cooling_exit(void) > +{ > + cleanup_cooling_devices(); > + pr_info("CPU hotplug cooling driver removed\n"); No, drop > +} > + > +module_init(cpu_hotplug_cooling_init); > +module_exit(cpu_hotplug_cooling_exit); > + > +MODULE_AUTHOR("John Madieu <john.madieu.xa@bp.renesas.com>"); > +MODULE_DESCRIPTION("CPU Hotplug Thermal Cooling Device"); > +MODULE_LICENSE("GPL"); > \ No newline at end of file Warning here > diff --git a/drivers/thermal/thermal_of.c b/drivers/thermal/thermal_of.c > index 0eb92d57a1e2..41655af1e419 100644 > --- a/drivers/thermal/thermal_of.c > +++ b/drivers/thermal/thermal_of.c > @@ -28,6 +28,7 @@ static const char * const trip_types[] = { > [THERMAL_TRIP_ACTIVE] = "active", > [THERMAL_TRIP_PASSIVE] = "passive", > [THERMAL_TRIP_HOT] = "hot", > + [THERMAL_TRIP_PLUG] = "plug", > [THERMAL_TRIP_CRITICAL] = "critical", > }; > > diff --git a/drivers/thermal/thermal_trace.h b/drivers/thermal/thermal_trace.h > index df8f4edd6068..c26a3aa7de5f 100644 > --- a/drivers/thermal/thermal_trace.h > +++ b/drivers/thermal/thermal_trace.h > @@ -12,6 +12,7 @@ > #include "thermal_core.h" > > TRACE_DEFINE_ENUM(THERMAL_TRIP_CRITICAL); > +TRACE_DEFINE_ENUM(THERMAL_TRIP_PLUG); > TRACE_DEFINE_ENUM(THERMAL_TRIP_HOT); > TRACE_DEFINE_ENUM(THERMAL_TRIP_PASSIVE); > TRACE_DEFINE_ENUM(THERMAL_TRIP_ACTIVE); > @@ -19,6 +20,7 @@ TRACE_DEFINE_ENUM(THERMAL_TRIP_ACTIVE); > #define show_tzt_type(type) \ > __print_symbolic(type, \ > { THERMAL_TRIP_CRITICAL, "CRITICAL"}, \ > + { THERMAL_TRIP_PLUG, "PLUG"}, \ > { THERMAL_TRIP_HOT, "HOT"}, \ > { THERMAL_TRIP_PASSIVE, "PASSIVE"}, \ > { THERMAL_TRIP_ACTIVE, "ACTIVE"}) > diff --git a/drivers/thermal/thermal_trip.c b/drivers/thermal/thermal_trip.c > index 4b8238468b53..373f6aaaf0da 100644 > --- a/drivers/thermal/thermal_trip.c > +++ b/drivers/thermal/thermal_trip.c > @@ -13,6 +13,7 @@ static const char *trip_type_names[] = { > [THERMAL_TRIP_ACTIVE] = "active", > [THERMAL_TRIP_PASSIVE] = "passive", > [THERMAL_TRIP_HOT] = "hot", > + [THERMAL_TRIP_PLUG] = "plug", > [THERMAL_TRIP_CRITICAL] = "critical", > }; > > diff --git a/include/uapi/linux/thermal.h b/include/uapi/linux/thermal.h > index 46a2633d33aa..5f76360c6f69 100644 > --- a/include/uapi/linux/thermal.h > +++ b/include/uapi/linux/thermal.h > @@ -15,6 +15,7 @@ enum thermal_trip_type { > THERMAL_TRIP_ACTIVE = 0, > THERMAL_TRIP_PASSIVE, > THERMAL_TRIP_HOT, > + THERMAL_TRIP_PLUG, > THERMAL_TRIP_CRITICAL, > }; > Best regards, Krzysztof
Hi John, On Sun, 9 Mar 2025 at 13:14, John Madieu <john.madieu.xa@bp.renesas.com> wrote: > Add thermal cooling mechanism that dynamically manages CPU online/offline > states to prevent overheating. It registers per-CPU cooling devices that can > take CPUs offline when thermal thresholds are excee and that integrates with > the Linux thermal framework as a cooling devices. > > Signed-off-by: John Madieu <john.madieu.xa@bp.renesas.com> Thanks for your patch! > --- /dev/null > +++ b/drivers/thermal/cpuplug_cooling.c > +static int register_cpu_hotplug_cooling(struct device_node *cpu_node, > + int cpu_id) > +{ > + hotplug_cdev = kzalloc(sizeof(*hotplug_cdev), GFP_KERNEL); > + if (!hotplug_cdev) { > + pr_err("Failed to allocate memory for cooling device\n"); scripts/checkpatch.pl: WARNING: Possible unnecessary 'out of memory' message and checkpatch is right, as the memory core already takes care of printing a message. > + return -ENOMEM; > + } Gr{oetje,eeting}s, Geert
Hi Krzysztof, Thanks for the review. > -----Original Message----- > From: Krzysztof Kozlowski <krzk@kernel.org> > Sent: Tuesday, March 11, 2025 8:31 AM > To: John Madieu <john.madieu.xa@bp.renesas.com>; geert+renesas@glider.be; > niklas.soderlund+renesas@ragnatech.se; conor+dt@kernel.org; > krzk+dt@kernel.org; robh@kernel.org; rafael@kernel.org; > daniel.lezcano@linaro.org > Subject: Re: [RFC PATCH 1/3] thermal/cpuplog_cooling: Add CPU hotplug > cooling driver > > On 09/03/2025 13:13, John Madieu wrote: > > + > > +/* Check if a trip point is of type "plug" */ static bool > > +is_plug_trip_point(struct device_node *trip_node) { > > + const char *trip_type_str; > > + > > + if (!trip_node) { > > + pr_err("Trip node is NULL\n"); > > + return false; > > + } > > + > > + if (of_property_read_string(trip_node, "type", &trip_type_str)) { > > + pr_err("Trip node missing 'type' property\n"); > > + return false; > > + } > > + > > + pr_info("Trip type: '%s'\n", trip_type_str); > > + > > + if (strcmp(trip_type_str, "plug") != 0) { > > type is object, not string. Where is ABI documented? For the type and its > value? I'll prepare it for v2. > > > > + pr_debug("Trip type is '%s', not 'plug' - skipping\n", > > + trip_type_str); > > + return false; > > + } > > + > > + return true; > > +} > > + > > +/* Init function */ > > +static int __init cpu_hotplug_cooling_init(void) { > > + struct device_node *thermal_zones, *thermal_zone; > > + int ret = 0; > > + int count = 0; > > + > > + bitmap_zero(cpu_cooling_registered, NR_CPUS); > > + > > + thermal_zones = of_find_node_by_name(NULL, "thermal-zones"); > > + if (!thermal_zones) { > > + pr_err("Missing thermal-zones node\n"); > > + return -EINVAL; > > + } > > + > > + /* Process each thermal zone */ > > + for_each_child_of_node(thermal_zones, thermal_zone) { > > + struct device_node *trips, *trip; > > + struct device_node *maps, *map; > > + bool found_plug = false; > > + > > + /* First find trips and get a specific plug trip */ > > + trips = of_find_node_by_name(thermal_zone, "trips"); > > + if (!trips) > > + continue; > > + > > + /* Find the emergency trip with type="plug" */ > > + for_each_child_of_node(trips, trip) { > > + if (is_plug_trip_point(trip)) { > > + found_plug = true; > > + break; > > + } > > + } > > + > > + /* If we didn't find a plug trip, no need to process this zone > */ > > + if (!found_plug) { > > + of_node_put(trips); > > + continue; > > + } > > + > > + maps = of_find_node_by_name(thermal_zone, "cooling-maps"); > > + if (!maps) { > > + of_node_put(trip); > > + of_node_put(trips); > > + continue; > > + } > > + > > + pr_info("Found 'plug' trip point, processing cooling > devices\n"); > > dev_info, or just drop. You are not supposed to print successes of > standard DT parsing. Noted. Thanks! > > > + > > + /* Find the specific cooling map that references our plug trip > */ > > + for_each_child_of_node(maps, map) { > > + struct device_node *trip_ref; > > + struct of_phandle_args cooling_spec; > > + int idx = 0; > > + > > + trip_ref = of_parse_phandle(map, "trip", 0); > > + if (!trip_ref || trip_ref != trip) { > > + if (trip_ref) > > + of_node_put(trip_ref); > > + continue; > > + } > > + of_node_put(trip_ref); > > + > > + if (!of_find_property(map, "cooling-device", NULL)) { > > + pr_err("Missing cooling-device property\n"); > > + continue; > > + } > > + > > + /* Iterate through all cooling-device entries */ > > + while (of_parse_phandle_with_args( > > + map, "cooling-device", > > + "#cooling-cells", idx++, > > + &cooling_spec) == 0) { > > + struct device_node *cpu_node = cooling_spec.np; > > + int cpu; > > + > > + if (!cpu_node) { > > + pr_err("CPU node at index %d is NULL\n", > > + idx - 1); > > + continue; > > + } > > + > > + cpu = of_cpu_node_to_id(cpu_node); > > + if (cpu < 0) { > > + pr_err("Failed to map CPU node %pOF to > logical ID\n", > > + cpu_node); > > + of_node_put(cpu_node); > > + continue; > > + } > > + > > + if (cpu >= num_possible_cpus()) { > > + pr_err("Invalid CPU ID %d (max %d)\n", > > + cpu, num_possible_cpus() - 1); > > + of_node_put(cpu_node); > > + continue; > > + } > > + > > + pr_info("Processing cooling device for CPU%d\n", > cpu); > > + ret = register_cpu_hotplug_cooling(cpu_node, cpu); > > + if (ret == 0) > > + count++; > > + > > + of_node_put(cpu_node); > > + } > > + break; /* Only process the first map that references our > trip */ > > + } > > + of_node_put(maps); > > + of_node_put(trip); > > + of_node_put(trips); > > + } > > + of_node_put(thermal_zones); > > + > > + if (count == 0) { > > + pr_err("No cooling devices registered\n"); > > + return -ENODEV; > > + } > > + > > + pr_info("CPU hotplug cooling driver initialized with %d devices\n", > > +count); > > Drop. Why would you print this on MIPS machine which does not care about > it, just because someone loaded a module? > Will remove this in v2. > > + return 0; > > +} > > + > > +/* Exit function */ > > +static void __exit cpu_hotplug_cooling_exit(void) { > > + cleanup_cooling_devices(); > > + pr_info("CPU hotplug cooling driver removed\n"); > > No, drop > Got it. > > > +} > > + > > +module_init(cpu_hotplug_cooling_init); > > +module_exit(cpu_hotplug_cooling_exit); > > + > > +MODULE_AUTHOR("John Madieu <john.madieu.xa@bp.renesas.com>"); > > +MODULE_DESCRIPTION("CPU Hotplug Thermal Cooling Device"); > > +MODULE_LICENSE("GPL"); > > \ No newline at end of file > > Warning here > Will be fixed in v2. > > diff --git a/drivers/thermal/thermal_of.c > > b/drivers/thermal/thermal_of.c index 0eb92d57a1e2..41655af1e419 100644 > > --- a/drivers/thermal/thermal_of.c > > +++ b/drivers/thermal/thermal_of.c > > @@ -28,6 +28,7 @@ static const char * const trip_types[] = { > > [THERMAL_TRIP_ACTIVE] = "active", > > [THERMAL_TRIP_PASSIVE] = "passive", > > [THERMAL_TRIP_HOT] = "hot", > > + [THERMAL_TRIP_PLUG] = "plug", > > [THERMAL_TRIP_CRITICAL] = "critical", > > }; > > > > diff --git a/drivers/thermal/thermal_trace.h > > b/drivers/thermal/thermal_trace.h index df8f4edd6068..c26a3aa7de5f > > 100644 > > --- a/drivers/thermal/thermal_trace.h > > +++ b/drivers/thermal/thermal_trace.h > > @@ -12,6 +12,7 @@ > > #include "thermal_core.h" > > > > TRACE_DEFINE_ENUM(THERMAL_TRIP_CRITICAL); > > +TRACE_DEFINE_ENUM(THERMAL_TRIP_PLUG); > > TRACE_DEFINE_ENUM(THERMAL_TRIP_HOT); > > TRACE_DEFINE_ENUM(THERMAL_TRIP_PASSIVE); > > TRACE_DEFINE_ENUM(THERMAL_TRIP_ACTIVE); > > @@ -19,6 +20,7 @@ TRACE_DEFINE_ENUM(THERMAL_TRIP_ACTIVE); > > #define show_tzt_type(type) \ > > __print_symbolic(type, \ > > { THERMAL_TRIP_CRITICAL, "CRITICAL"}, \ > > + { THERMAL_TRIP_PLUG, "PLUG"}, \ > > { THERMAL_TRIP_HOT, "HOT"}, \ > > { THERMAL_TRIP_PASSIVE, "PASSIVE"}, \ > > { THERMAL_TRIP_ACTIVE, "ACTIVE"}) > > diff --git a/drivers/thermal/thermal_trip.c > > b/drivers/thermal/thermal_trip.c index 4b8238468b53..373f6aaaf0da > > 100644 > > --- a/drivers/thermal/thermal_trip.c > > +++ b/drivers/thermal/thermal_trip.c > > @@ -13,6 +13,7 @@ static const char *trip_type_names[] = { > > [THERMAL_TRIP_ACTIVE] = "active", > > [THERMAL_TRIP_PASSIVE] = "passive", > > [THERMAL_TRIP_HOT] = "hot", > > + [THERMAL_TRIP_PLUG] = "plug", > > [THERMAL_TRIP_CRITICAL] = "critical", }; > > > > diff --git a/include/uapi/linux/thermal.h > > b/include/uapi/linux/thermal.h index 46a2633d33aa..5f76360c6f69 100644 > > --- a/include/uapi/linux/thermal.h > > +++ b/include/uapi/linux/thermal.h > > @@ -15,6 +15,7 @@ enum thermal_trip_type { > > THERMAL_TRIP_ACTIVE = 0, > > THERMAL_TRIP_PASSIVE, > > THERMAL_TRIP_HOT, > > + THERMAL_TRIP_PLUG, > > THERMAL_TRIP_CRITICAL, > > }; > > > > > Best regards, > Krzysztof Regards, John
Hi Geert, Thanks for your review. > -----Original Message----- > From: Geert Uytterhoeven <geert@linux-m68k.org> > Sent: Tuesday, March 11, 2025 9:28 AM > To: John Madieu <john.madieu.xa@bp.renesas.com> > Subject: Re: [RFC PATCH 1/3] thermal/cpuplog_cooling: Add CPU hotplug > cooling driver > > Hi John, > > On Sun, 9 Mar 2025 at 13:14, John Madieu <john.madieu.xa@bp.renesas.com> > wrote: > > Add thermal cooling mechanism that dynamically manages CPU > > online/offline states to prevent overheating. It registers per-CPU > > cooling devices that can take CPUs offline when thermal thresholds are > > excee and that integrates with the Linux thermal framework as a cooling > devices. > > > > Signed-off-by: John Madieu <john.madieu.xa@bp.renesas.com> > > Thanks for your patch! > > > --- /dev/null > > +++ b/drivers/thermal/cpuplug_cooling.c > > > +static int register_cpu_hotplug_cooling(struct device_node *cpu_node, > > + int cpu_id) { > > > + hotplug_cdev = kzalloc(sizeof(*hotplug_cdev), GFP_KERNEL); > > + if (!hotplug_cdev) { > > + pr_err("Failed to allocate memory for cooling > > + device\n"); > > scripts/checkpatch.pl: > > WARNING: Possible unnecessary 'out of memory' message > > and checkpatch is right, as the memory core already takes care of printing > a message. > Will be removed in v2. > > + return -ENOMEM; > > + } > > Gr{oetje,eeting}s, > > Geert > > -- Regards, John
diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig index d3f9686e26e7..6b0687f0d635 100644 --- a/drivers/thermal/Kconfig +++ b/drivers/thermal/Kconfig @@ -202,6 +202,18 @@ config CPU_IDLE_THERMAL This implements the CPU cooling mechanism through idle injection. This will throttle the CPU by injecting idle cycle. + +config CPU_HOTPLUG_THERMAL + bool "CPU hotplug cooling device" + depends on THERMAL + depends on HOTPLUG_CPU + help + Enable this to manage platform thermals using CPU hotplug. + This can offline CPUs when a temperature threshold is exceeded and + bring them back online when it drops below the reset temperature. + The boot CPU is never offlined. + + If in doubt, say N. endif config DEVFREQ_THERMAL diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile index 9abf43a74f2b..7b3648daabd2 100644 --- a/drivers/thermal/Makefile +++ b/drivers/thermal/Makefile @@ -28,6 +28,7 @@ thermal_sys-$(CONFIG_THERMAL_GOV_POWER_ALLOCATOR) += gov_power_allocator.o # cpufreq cooling thermal_sys-$(CONFIG_CPU_FREQ_THERMAL) += cpufreq_cooling.o thermal_sys-$(CONFIG_CPU_IDLE_THERMAL) += cpuidle_cooling.o +thermal_sys-$(CONFIG_CPU_HOTPLUG_THERMAL) += cpuplug_cooling.o # devfreq cooling thermal_sys-$(CONFIG_DEVFREQ_THERMAL) += devfreq_cooling.o diff --git a/drivers/thermal/cpuplug_cooling.c b/drivers/thermal/cpuplug_cooling.c new file mode 100644 index 000000000000..1f62325f0665 --- /dev/null +++ b/drivers/thermal/cpuplug_cooling.c @@ -0,0 +1,363 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * CPU Hotplug Thermal Cooling Device + * + * Copyright (C) 2025 Renesas Electronics Corporation + */ +#define pr_fmt(fmt) "cpu-hotplug-thermal: " fmt + +#include <linux/cpu.h> +#include <linux/cpumask.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/list.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/of.h> +#include <linux/slab.h> +#include <linux/thermal.h> +#include <linux/types.h> + +#define COOLING_DEVICE_NAME "cpu-hotplug" + +/* CPU Hotplug cooling device private data structure */ +struct cpu_hotplug_cooling_device { + struct thermal_cooling_device *cdev; + int cpu_id; + unsigned long cur_state; + bool cpu_online; + struct list_head node; +}; + +static LIST_HEAD(cooling_devices); +static DEFINE_MUTEX(cooling_list_lock); + +/* Track which CPUs already have cooling devices */ +static DECLARE_BITMAP(cpu_cooling_registered, NR_CPUS); + +static inline bool is_boot_cpu(unsigned int cpu) +{ + return cpu == cpumask_first(cpu_online_mask); +} + +static int cpu_hotplug_get_max_state(struct thermal_cooling_device *cdev, + unsigned long *state) +{ + *state = 1; /* We only have two states: on/off */ + return 0; +} + +/* Get current cooling state */ +static int cpu_hotplug_get_cur_state(struct thermal_cooling_device *cdev, + unsigned long *state) +{ + struct cpu_hotplug_cooling_device *hotplug_cdev = cdev->devdata; + + *state = hotplug_cdev->cur_state; + return 0; +} + +static int cpu_hotplug_set_cur_state(struct thermal_cooling_device *cdev, + unsigned long state) +{ + struct cpu_hotplug_cooling_device *hotplug_cdev = cdev->devdata; + int cpu, ret = 0; + + /* Only take action if state has changed */ + if (hotplug_cdev->cur_state == state) + return 0; + + /* Store the current state */ + hotplug_cdev->cur_state = state; + cpu = hotplug_cdev->cpu_id; + + /* Skip if it's the boot CPU */ + if (is_boot_cpu(cpu)) + return 0; + + if (state == 0) { + /* Cooling off - bring CPU online if it's offline */ + if (!cpu_online(cpu)) { + pr_info("CPU%d coming back online\n", cpu); + ret = add_cpu(cpu); + if (ret) + pr_err("Failed to bring CPU%d online: %d\n", cpu, ret); + else + hotplug_cdev->cpu_online = true; + } + } else { + /* Cooling on - take CPU offline if it's online */ + if (cpu_online(cpu)) { + pr_info("CPU%d going offline due to overheating\n", cpu); + ret = remove_cpu(cpu); + if (ret) + pr_err("Failed to offline CPU%d: %d\n", cpu, ret); + else + hotplug_cdev->cpu_online = false; + } + } + + return 0; +} + +static const struct thermal_cooling_device_ops cpu_hotplug_cooling_ops = { + .get_max_state = cpu_hotplug_get_max_state, + .get_cur_state = cpu_hotplug_get_cur_state, + .set_cur_state = cpu_hotplug_set_cur_state, +}; + +static int register_cpu_hotplug_cooling(struct device_node *cpu_node, + int cpu_id) +{ + struct cpu_hotplug_cooling_device *hotplug_cdev; + struct thermal_cooling_device *cdev; + char cooling_name[32]; + + /* Check if we already registered this CPU */ + if (test_bit(cpu_id, cpu_cooling_registered)) { + pr_info("Cooling device already registered for CPU%d\n", cpu_id); + return 0; + } + + /* Skip the boot CPU */ + if (is_boot_cpu(cpu_id)) { + pr_info("Skipping boot CPU%d for hotplug cooling\n", cpu_id); + return 0; + } + + hotplug_cdev = kzalloc(sizeof(*hotplug_cdev), GFP_KERNEL); + if (!hotplug_cdev) { + pr_err("Failed to allocate memory for cooling device\n"); + return -ENOMEM; + } + + /* Initialize cooling device */ + hotplug_cdev->cpu_id = cpu_id; + hotplug_cdev->cur_state = 0; + hotplug_cdev->cpu_online = cpu_online(cpu_id); + + /* Unique cooling device name */ + snprintf(cooling_name, sizeof(cooling_name), "%s-%d", + COOLING_DEVICE_NAME, hotplug_cdev->cpu_id); + + /* Register cooling device with a unique name - using CPU node */ + cdev = thermal_of_cooling_device_register( + cpu_node, cooling_name, hotplug_cdev, &cpu_hotplug_cooling_ops); + if (IS_ERR(cdev)) { + pr_err("Failed to register %s: %ld\n", cooling_name, + PTR_ERR(cdev)); + kfree(hotplug_cdev); + return PTR_ERR(cdev); + } + + hotplug_cdev->cdev = cdev; + + /* Mark this CPU as having a registered cooling device */ + set_bit(cpu_id, cpu_cooling_registered); + + /* Add to our list for cleanup later */ + mutex_lock(&cooling_list_lock); + list_add(&hotplug_cdev->node, &cooling_devices); + mutex_unlock(&cooling_list_lock); + + pr_info("Successfully registered %s for CPU%d\n", cooling_name, + hotplug_cdev->cpu_id); + + return 0; +} + +/* Cleanup all cooling devices */ +static void cleanup_cooling_devices(void) +{ + struct cpu_hotplug_cooling_device *hotplug_cdev, *next; + + mutex_lock(&cooling_list_lock); + list_for_each_entry_safe(hotplug_cdev, next, &cooling_devices, node) { + pr_info("Unregistering cooling device for CPU%d\n", + hotplug_cdev->cpu_id); + + /* Clear the registration bit */ + clear_bit(hotplug_cdev->cpu_id, cpu_cooling_registered); + + /* Remove from list */ + list_del(&hotplug_cdev->node); + + /* Unregister cooling device */ + thermal_cooling_device_unregister(hotplug_cdev->cdev); + + /* Make sure CPU is back online */ + if (!hotplug_cdev->cpu_online) { + int cpu = hotplug_cdev->cpu_id; + if (!is_boot_cpu(cpu) && !cpu_online(cpu)) { + pr_info("Bringing CPU%d back online during module unload\n", cpu); + if (add_cpu(cpu)) + pr_err("Failed to bring CPU%d online\n", cpu); + } + } + + /* Free memory */ + kfree(hotplug_cdev); + } + mutex_unlock(&cooling_list_lock); +} + +/* Check if a trip point is of type "plug" */ +static bool is_plug_trip_point(struct device_node *trip_node) +{ + const char *trip_type_str; + + if (!trip_node) { + pr_err("Trip node is NULL\n"); + return false; + } + + if (of_property_read_string(trip_node, "type", &trip_type_str)) { + pr_err("Trip node missing 'type' property\n"); + return false; + } + + pr_info("Trip type: '%s'\n", trip_type_str); + + if (strcmp(trip_type_str, "plug") != 0) { + pr_debug("Trip type is '%s', not 'plug' - skipping\n", + trip_type_str); + return false; + } + + return true; +} + +/* Init function */ +static int __init cpu_hotplug_cooling_init(void) +{ + struct device_node *thermal_zones, *thermal_zone; + int ret = 0; + int count = 0; + + bitmap_zero(cpu_cooling_registered, NR_CPUS); + + thermal_zones = of_find_node_by_name(NULL, "thermal-zones"); + if (!thermal_zones) { + pr_err("Missing thermal-zones node\n"); + return -EINVAL; + } + + /* Process each thermal zone */ + for_each_child_of_node(thermal_zones, thermal_zone) { + struct device_node *trips, *trip; + struct device_node *maps, *map; + bool found_plug = false; + + /* First find trips and get a specific plug trip */ + trips = of_find_node_by_name(thermal_zone, "trips"); + if (!trips) + continue; + + /* Find the emergency trip with type="plug" */ + for_each_child_of_node(trips, trip) { + if (is_plug_trip_point(trip)) { + found_plug = true; + break; + } + } + + /* If we didn't find a plug trip, no need to process this zone */ + if (!found_plug) { + of_node_put(trips); + continue; + } + + maps = of_find_node_by_name(thermal_zone, "cooling-maps"); + if (!maps) { + of_node_put(trip); + of_node_put(trips); + continue; + } + + pr_info("Found 'plug' trip point, processing cooling devices\n"); + + /* Find the specific cooling map that references our plug trip */ + for_each_child_of_node(maps, map) { + struct device_node *trip_ref; + struct of_phandle_args cooling_spec; + int idx = 0; + + trip_ref = of_parse_phandle(map, "trip", 0); + if (!trip_ref || trip_ref != trip) { + if (trip_ref) + of_node_put(trip_ref); + continue; + } + of_node_put(trip_ref); + + if (!of_find_property(map, "cooling-device", NULL)) { + pr_err("Missing cooling-device property\n"); + continue; + } + + /* Iterate through all cooling-device entries */ + while (of_parse_phandle_with_args( + map, "cooling-device", + "#cooling-cells", idx++, + &cooling_spec) == 0) { + struct device_node *cpu_node = cooling_spec.np; + int cpu; + + if (!cpu_node) { + pr_err("CPU node at index %d is NULL\n", + idx - 1); + continue; + } + + cpu = of_cpu_node_to_id(cpu_node); + if (cpu < 0) { + pr_err("Failed to map CPU node %pOF to logical ID\n", + cpu_node); + of_node_put(cpu_node); + continue; + } + + if (cpu >= num_possible_cpus()) { + pr_err("Invalid CPU ID %d (max %d)\n", + cpu, num_possible_cpus() - 1); + of_node_put(cpu_node); + continue; + } + + pr_info("Processing cooling device for CPU%d\n", cpu); + ret = register_cpu_hotplug_cooling(cpu_node, cpu); + if (ret == 0) + count++; + + of_node_put(cpu_node); + } + break; /* Only process the first map that references our trip */ + } + of_node_put(maps); + of_node_put(trip); + of_node_put(trips); + } + of_node_put(thermal_zones); + + if (count == 0) { + pr_err("No cooling devices registered\n"); + return -ENODEV; + } + + pr_info("CPU hotplug cooling driver initialized with %d devices\n", count); + return 0; +} + +/* Exit function */ +static void __exit cpu_hotplug_cooling_exit(void) +{ + cleanup_cooling_devices(); + pr_info("CPU hotplug cooling driver removed\n"); +} + +module_init(cpu_hotplug_cooling_init); +module_exit(cpu_hotplug_cooling_exit); + +MODULE_AUTHOR("John Madieu <john.madieu.xa@bp.renesas.com>"); +MODULE_DESCRIPTION("CPU Hotplug Thermal Cooling Device"); +MODULE_LICENSE("GPL"); \ No newline at end of file diff --git a/drivers/thermal/thermal_of.c b/drivers/thermal/thermal_of.c index 0eb92d57a1e2..41655af1e419 100644 --- a/drivers/thermal/thermal_of.c +++ b/drivers/thermal/thermal_of.c @@ -28,6 +28,7 @@ static const char * const trip_types[] = { [THERMAL_TRIP_ACTIVE] = "active", [THERMAL_TRIP_PASSIVE] = "passive", [THERMAL_TRIP_HOT] = "hot", + [THERMAL_TRIP_PLUG] = "plug", [THERMAL_TRIP_CRITICAL] = "critical", }; diff --git a/drivers/thermal/thermal_trace.h b/drivers/thermal/thermal_trace.h index df8f4edd6068..c26a3aa7de5f 100644 --- a/drivers/thermal/thermal_trace.h +++ b/drivers/thermal/thermal_trace.h @@ -12,6 +12,7 @@ #include "thermal_core.h" TRACE_DEFINE_ENUM(THERMAL_TRIP_CRITICAL); +TRACE_DEFINE_ENUM(THERMAL_TRIP_PLUG); TRACE_DEFINE_ENUM(THERMAL_TRIP_HOT); TRACE_DEFINE_ENUM(THERMAL_TRIP_PASSIVE); TRACE_DEFINE_ENUM(THERMAL_TRIP_ACTIVE); @@ -19,6 +20,7 @@ TRACE_DEFINE_ENUM(THERMAL_TRIP_ACTIVE); #define show_tzt_type(type) \ __print_symbolic(type, \ { THERMAL_TRIP_CRITICAL, "CRITICAL"}, \ + { THERMAL_TRIP_PLUG, "PLUG"}, \ { THERMAL_TRIP_HOT, "HOT"}, \ { THERMAL_TRIP_PASSIVE, "PASSIVE"}, \ { THERMAL_TRIP_ACTIVE, "ACTIVE"}) diff --git a/drivers/thermal/thermal_trip.c b/drivers/thermal/thermal_trip.c index 4b8238468b53..373f6aaaf0da 100644 --- a/drivers/thermal/thermal_trip.c +++ b/drivers/thermal/thermal_trip.c @@ -13,6 +13,7 @@ static const char *trip_type_names[] = { [THERMAL_TRIP_ACTIVE] = "active", [THERMAL_TRIP_PASSIVE] = "passive", [THERMAL_TRIP_HOT] = "hot", + [THERMAL_TRIP_PLUG] = "plug", [THERMAL_TRIP_CRITICAL] = "critical", }; diff --git a/include/uapi/linux/thermal.h b/include/uapi/linux/thermal.h index 46a2633d33aa..5f76360c6f69 100644 --- a/include/uapi/linux/thermal.h +++ b/include/uapi/linux/thermal.h @@ -15,6 +15,7 @@ enum thermal_trip_type { THERMAL_TRIP_ACTIVE = 0, THERMAL_TRIP_PASSIVE, THERMAL_TRIP_HOT, + THERMAL_TRIP_PLUG, THERMAL_TRIP_CRITICAL, };
Add thermal cooling mechanism that dynamically manages CPU online/offline states to prevent overheating. It registers per-CPU cooling devices that can take CPUs offline when thermal thresholds are excee and that integrates with the Linux thermal framework as a cooling devices. Signed-off-by: John Madieu <john.madieu.xa@bp.renesas.com> --- drivers/thermal/Kconfig | 12 + drivers/thermal/Makefile | 1 + drivers/thermal/cpuplug_cooling.c | 363 ++++++++++++++++++++++++++++++ drivers/thermal/thermal_of.c | 1 + drivers/thermal/thermal_trace.h | 2 + drivers/thermal/thermal_trip.c | 1 + include/uapi/linux/thermal.h | 1 + 7 files changed, 381 insertions(+) create mode 100644 drivers/thermal/cpuplug_cooling.c