selftests/thermel/intel: Add test to read workload hint

Some SoCs have in built firmware support to classify current running
workload and pass to OS for making power management decisions.

This test program waits for notification of workload type change
and prints. This program can be used to test this feature and also
allows other user space programs to use as a reference.

Signed-off-by: Srinivas Pandruvada <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>

Author: spandruvada

tools/testing/selftests/Makefile

@@ -85,6 +85,7 @@ TARGETS += syscall_user_dispatch
 TARGETS += sysctl
 TARGETS += tc-testing
 TARGETS += tdx
+TARGETS += thermal/intel/workload_hint
 TARGETS += timens
 ifneq (1, $(quicktest))
 TARGETS += timers

tools/testing/selftests/thermal/intel/workload_hint/Makefile

@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: GPL-2.0
+ifndef CROSS_COMPILE
+uname_M := $(shell uname -m 2>/dev/null || echo not)
+ARCH ?= $(shell echo $(uname_M) | sed -e s/i.86/x86/ -e s/x86_64/x86/)
+
+ifeq ($(ARCH),x86)
+TEST_GEN_PROGS := workload_hint_test
+
+include ../../../lib.mk
+
+endif
+endif

tools/testing/selftests/thermal/intel/workload_hint/workload_hint_test.c

@@ -0,0 +1,157 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define _GNU_SOURCE
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <signal.h>
+
+#define WORKLOAD_NOTIFICATION_DELAY_ATTRIBUTE "/sys/bus/pci/devices/0000:00:04.0/workload_hint/notification_delay_ms"
+#define WORKLOAD_ENABLE_ATTRIBUTE "/sys/bus/pci/devices/0000:00:04.0/workload_hint/workload_hint_enable"
+#define WORKLOAD_TYPE_INDEX_ATTRIBUTE  "/sys/bus/pci/devices/0000:00:04.0/workload_hint/workload_type_index"
+
+static const char * const workload_types[] = {
+	"idle",
+	"battery_life",
+	"sustained",
+	"bursty",
+	NULL
+};
+
+#define WORKLOAD_TYPE_MAX_INDEX	3
+
+void workload_hint_exit(int signum)
+{
+	int fd;
+
+	/* Disable feature via sysfs knob */
+
+	fd = open(WORKLOAD_ENABLE_ATTRIBUTE, O_RDWR);
+	if (fd < 0) {
+		perror("Unable to open workload type feature enable file\n");
+		exit(1);
+	}
+
+	if (write(fd, "0\n", 2) < 0) {
+		perror("Can' disable workload hints\n");
+		exit(1);
+	}
+
+	printf("Disabled workload type prediction\n");
+
+	close(fd);
+}
+
+int main(int argc, char **argv)
+{
+	struct pollfd ufd;
+	char index_str[4];
+	int fd, ret, index;
+	char delay_str[64];
+	int delay = 0;
+
+	printf("Usage: workload_hint_test [notification delay in milli seconds]\n");
+
+	if (argc > 1) {
+		ret = sscanf(argv[1], "%d", &delay);
+		if (ret < 0) {
+			printf("Invalid delay\n");
+			exit(1);
+		}
+
+		printf("Setting notification delay to %d ms\n", delay);
+		if (delay < 0)
+			exit(1);
+
+		sprintf(delay_str, "%s\n", argv[1]);
+
+		sprintf(delay_str, "%s\n", argv[1]);
+		fd = open(WORKLOAD_NOTIFICATION_DELAY_ATTRIBUTE, O_RDWR);
+		if (fd < 0) {
+			perror("Unable to open workload notification delay\n");
+			exit(1);
+		}
+
+		if (write(fd, delay_str, strlen(delay_str)) < 0) {
+			perror("Can't set delay\n");
+			exit(1);
+		}
+
+		close(fd);
+	}
+
+	if (signal(SIGINT, workload_hint_exit) == SIG_IGN)
+		signal(SIGINT, SIG_IGN);
+	if (signal(SIGHUP, workload_hint_exit) == SIG_IGN)
+		signal(SIGHUP, SIG_IGN);
+	if (signal(SIGTERM, workload_hint_exit) == SIG_IGN)
+		signal(SIGTERM, SIG_IGN);
+
+	/* Enable feature via sysfs knob */
+	fd = open(WORKLOAD_ENABLE_ATTRIBUTE, O_RDWR);
+	if (fd < 0) {
+		perror("Unable to open workload type feature enable file\n");
+		exit(1);
+	}
+
+	if (write(fd, "1\n", 2) < 0) {
+		perror("Can' enable workload hints\n");
+		exit(1);
+	}
+
+	close(fd);
+
+	printf("Enabled workload type prediction\n");
+
+	while (1) {
+		fd = open(WORKLOAD_TYPE_INDEX_ATTRIBUTE, O_RDONLY);
+		if (fd < 0) {
+			perror("Unable to open workload type file\n");
+			exit(1);
+		}
+
+		if ((lseek(fd, 0L, SEEK_SET)) < 0) {
+			fprintf(stderr, "Failed to set pointer to beginning\n");
+			exit(1);
+		}
+
+		if (read(fd, index_str, sizeof(index_str)) < 0) {
+			fprintf(stderr, "Failed to read from:%s\n",
+			WORKLOAD_TYPE_INDEX_ATTRIBUTE);
+			exit(1);
+		}
+
+		ufd.fd = fd;
+		ufd.events = POLLPRI;
+
+		ret = poll(&ufd, 1, -1);
+		if (ret < 0) {
+			perror("poll error");
+			exit(1);
+		} else if (ret == 0) {
+			printf("Poll Timeout\n");
+		} else {
+			if ((lseek(fd, 0L, SEEK_SET)) < 0) {
+				fprintf(stderr, "Failed to set pointer to beginning\n");
+				exit(1);
+			}
+
+			if (read(fd, index_str, sizeof(index_str)) < 0)
+				exit(0);
+
+			ret = sscanf(index_str, "%d", &index);
+			if (ret < 0)
+				break;
+			if (index > WORKLOAD_TYPE_MAX_INDEX)
+				printf("Invalid workload type index\n");
+			else
+				printf("workload type:%s\n", workload_types[index]);
+		}
+
+		close(fd);
+	}
+}