On Fri, 27 Aug 2021 12:47:53 +0900
William Breathitt Gray <vilhelm.gray@xxxxxxxxx> wrote:
> This creates an example Counter program under tools/counter/*
> to exemplify the Counter character device interface.
>
> Cc: Pavel Machek <pavel@xxxxxx>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@xxxxxxxxx>
It's great to have this example, but it very much an example rather than
a generic tool. You may want to revisit and provide a more generic
tool in the future.
A trivial comment about using a loop inline.
Jonathan
> ---
> MAINTAINERS | 1 +
> tools/Makefile | 13 ++---
> tools/counter/Build | 1 +
> tools/counter/Makefile | 53 +++++++++++++++++++
> tools/counter/counter_example.c | 93 +++++++++++++++++++++++++++++++++
> 5 files changed, 155 insertions(+), 6 deletions(-)
> create mode 100644 tools/counter/Build
> create mode 100644 tools/counter/Makefile
> create mode 100644 tools/counter/counter_example.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index f2fdd2202605..57dc9b6ff82a 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -4782,6 +4782,7 @@ F: Documentation/driver-api/generic-counter.rst
> F: drivers/counter/
> F: include/linux/counter.h
> F: include/uapi/linux/counter.h
> +F: tools/counter/
>
> CP2615 I2C DRIVER
> M: Bence Csókás <bence98@xxxxxxxxxx>
> diff --git a/tools/Makefile b/tools/Makefile
> index 7e9d34ddd74c..5da1fde03a9a 100644
> --- a/tools/Makefile
> +++ b/tools/Makefile
> @@ -12,6 +12,7 @@ help:
> @echo ' acpi - ACPI tools'
> @echo ' bpf - misc BPF tools'
> @echo ' cgroup - cgroup tools'
> + @echo ' counter - counter tools'
> @echo ' cpupower - a tool for all things x86 CPU power'
> @echo ' debugging - tools for debugging'
> @echo ' firewire - the userspace part of nosy, an IEEE-1394 traffic sniffer'
> @@ -65,7 +66,7 @@ acpi: FORCE
> cpupower: FORCE
> $(call descend,power/$@)
>
> -cgroup firewire hv guest bootconfig spi usb virtio vm bpf iio gpio objtool leds wmi pci firmware debugging tracing: FORCE
> +cgroup counter firewire hv guest bootconfig spi usb virtio vm bpf iio gpio objtool leds wmi pci firmware debugging tracing: FORCE
> $(call descend,$@)
>
> bpf/%: FORCE
> @@ -100,7 +101,7 @@ freefall: FORCE
> kvm_stat: FORCE
> $(call descend,kvm/$@)
>
> -all: acpi cgroup cpupower gpio hv firewire liblockdep \
> +all: acpi cgroup counter cpupower gpio hv firewire liblockdep \
> perf selftests bootconfig spi turbostat usb \
> virtio vm bpf x86_energy_perf_policy \
> tmon freefall iio objtool kvm_stat wmi \
> @@ -112,7 +113,7 @@ acpi_install:
> cpupower_install:
> $(call descend,power/$(@:_install=),install)
>
> -cgroup_install firewire_install gpio_install hv_install iio_install perf_install bootconfig_install spi_install usb_install virtio_install vm_install bpf_install objtool_install wmi_install pci_install debugging_install tracing_install:
> +cgroup_install counter_install firewire_install gpio_install hv_install iio_install perf_install bootconfig_install spi_install usb_install virtio_install vm_install bpf_install objtool_install wmi_install pci_install debugging_install tracing_install:
> $(call descend,$(@:_install=),install)
>
> liblockdep_install:
> @@ -133,7 +134,7 @@ freefall_install:
> kvm_stat_install:
> $(call descend,kvm/$(@:_install=),install)
>
> -install: acpi_install cgroup_install cpupower_install gpio_install \
> +install: acpi_install cgroup_install counter_install cpupower_install gpio_install \
> hv_install firewire_install iio_install liblockdep_install \
> perf_install selftests_install turbostat_install usb_install \
> virtio_install vm_install bpf_install x86_energy_perf_policy_install \
> @@ -147,7 +148,7 @@ acpi_clean:
> cpupower_clean:
> $(call descend,power/cpupower,clean)
>
> -cgroup_clean hv_clean firewire_clean bootconfig_clean spi_clean usb_clean virtio_clean vm_clean wmi_clean bpf_clean iio_clean gpio_clean objtool_clean leds_clean pci_clean firmware_clean debugging_clean tracing_clean:
> +cgroup_clean counter_clean hv_clean firewire_clean bootconfig_clean spi_clean usb_clean virtio_clean vm_clean wmi_clean bpf_clean iio_clean gpio_clean objtool_clean leds_clean pci_clean firmware_clean debugging_clean tracing_clean:
> $(call descend,$(@:_clean=),clean)
>
> liblockdep_clean:
> @@ -181,7 +182,7 @@ freefall_clean:
> build_clean:
> $(call descend,build,clean)
>
> -clean: acpi_clean cgroup_clean cpupower_clean hv_clean firewire_clean \
> +clean: acpi_clean cgroup_clean counter_clean cpupower_clean hv_clean firewire_clean \
This is far from alphabetical, though I have no idea if there is any strong convention on where
to add new entries.
> perf_clean selftests_clean turbostat_clean bootconfig_clean spi_clean usb_clean virtio_clean \
> vm_clean bpf_clean iio_clean x86_energy_perf_policy_clean tmon_clean \
> freefall_clean build_clean libbpf_clean libsubcmd_clean liblockdep_clean \
> diff --git a/tools/counter/Build b/tools/counter/Build
> new file mode 100644
> index 000000000000..33f4a51d715e
> --- /dev/null
> +++ b/tools/counter/Build
> @@ -0,0 +1 @@
> +counter_example-y += counter_example.o
> diff --git a/tools/counter/Makefile b/tools/counter/Makefile
> new file mode 100644
> index 000000000000..5ebc195fd9c0
> --- /dev/null
> +++ b/tools/counter/Makefile
> @@ -0,0 +1,53 @@
> +# SPDX-License-Identifier: GPL-2.0
> +include ../scripts/Makefile.include
> +
> +bindir ?= /usr/bin
> +
> +ifeq ($(srctree),)
> +srctree := $(patsubst %/,%,$(dir $(CURDIR)))
> +srctree := $(patsubst %/,%,$(dir $(srctree)))
> +endif
> +
> +# Do not use make's built-in rules
> +# (this improves performance and avoids hard-to-debug behaviour);
> +MAKEFLAGS += -r
> +
> +override CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include
> +
> +ALL_TARGETS := counter_example
> +ALL_PROGRAMS := $(patsubst %,$(OUTPUT)%,$(ALL_TARGETS))
> +
> +all: $(ALL_PROGRAMS)
> +
> +export srctree OUTPUT CC LD CFLAGS
> +include $(srctree)/tools/build/Makefile.include
> +
> +#
> +# We need the following to be outside of kernel tree
> +#
> +$(OUTPUT)include/linux/counter.h: ../../include/uapi/linux/counter.h
> + mkdir -p $(OUTPUT)include/linux 2>&1 || true
> + ln -sf $(CURDIR)/../../include/uapi/linux/counter.h $@
> +
> +prepare: $(OUTPUT)include/linux/counter.h
> +
> +COUNTER_EXAMPLE := $(OUTPUT)counter_example.o
> +$(COUNTER_EXAMPLE): prepare FORCE
> + $(Q)$(MAKE) $(build)=counter_example
> +$(OUTPUT)counter_example: $(COUNTER_EXAMPLE)
> + $(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) $< -o $@
> +
> +clean:
> + rm -f $(ALL_PROGRAMS)
> + rm -rf $(OUTPUT)include/linux/counter.h
> + find $(if $(OUTPUT),$(OUTPUT),.) -name '*.o' -delete -o -name '\.*.d' -delete
> +
> +install: $(ALL_PROGRAMS)
> + install -d -m 755 $(DESTDIR)$(bindir); \
> + for program in $(ALL_PROGRAMS); do \
> + install $$program $(DESTDIR)$(bindir); \
> + done
> +
> +FORCE:
> +
> +.PHONY: all install clean FORCE prepare
> diff --git a/tools/counter/counter_example.c b/tools/counter/counter_example.c
> new file mode 100644
> index 000000000000..90d69fb9463b
> --- /dev/null
> +++ b/tools/counter/counter_example.c
> @@ -0,0 +1,93 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/* Counter - example userspace application
> + *
> + * The userspace application opens /dev/counter0, configures the
> + * COUNTER_EVENT_INDEX event channel 0 to gather Count 0 count and Count
> + * 1 count, and prints out the data as it becomes available on the
> + * character device node.
> + *
> + * Copyright (C) 2021 William Breathitt Gray
> + */
> +#include <errno.h>
> +#include <fcntl.h>
> +#include <linux/counter.h>
> +#include <stdio.h>
> +#include <string.h>
> +#include <sys/ioctl.h>
> +#include <unistd.h>
> +
> +static struct counter_watch watches[2] = {
> + {
> + /* Component data: Count 0 count */
> + .component.type = COUNTER_COMPONENT_COUNT,
> + .component.scope = COUNTER_SCOPE_COUNT,
> + .component.parent = 0,
> + /* Event type: Index */
> + .event = COUNTER_EVENT_INDEX,
> + /* Device event channel 0 */
> + .channel = 0,
> + },
> + {
> + /* Component data: Count 1 count */
> + .component.type = COUNTER_COMPONENT_COUNT,
> + .component.scope = COUNTER_SCOPE_COUNT,
> + .component.parent = 1,
> + /* Event type: Index */
> + .event = COUNTER_EVENT_INDEX,
> + /* Device event channel 0 */
> + .channel = 0,
> + },
> +};
> +
> +int main(void)
> +{
> + int fd;
> + int ret;
> + struct counter_event event_data[2];
> +
> + fd = open("/dev/counter0", O_RDWR);
You may want to make this tool more flexible at somepoint. It is
in tools rather than Documentation after all.
> + if (fd == -1) {
> + perror("Unable to open /dev/counter0");
> + return -errno;
> + }
> +
> + ret = ioctl(fd, COUNTER_ADD_WATCH_IOCTL, watches);
Loop?
> + if (ret == -1) {
> + perror("Error adding watches[0]");
> + return -errno;
> + }
> + ret = ioctl(fd, COUNTER_ADD_WATCH_IOCTL, watches + 1);
> + if (ret == -1) {
> + perror("Error adding watches[1]");
> + return -errno;
> + }
> + ret = ioctl(fd, COUNTER_ENABLE_EVENTS_IOCTL);
> + if (ret == -1) {
> + perror("Error enabling events");
> + return -errno;
> + }
> +
> + for (;;) {
> + ret = read(fd, event_data, sizeof(event_data));
> + if (ret == -1) {
> + perror("Failed to read event data");
> + return 1;
> + }
> +
> + if (ret != sizeof(event_data)) {
> + fprintf(stderr, "Failed to read event data\n");
> + return -EIO;
> + }
> +
> + printf("Timestamp 0: %llu\tCount 0: %llu\n"
> + "Error Message 0: %s\n"
> + "Timestamp 1: %llu\tCount 1: %llu\n"
> + "Error Message 1: %s\n",
> + event_data[0].timestamp, event_data[0].value,
> + strerror(event_data[0].status),
> + event_data[1].timestamp, event_data[1].value,
> + strerror(event_data[1].status));
> + }
> +
> + return 0;
> +}
