selftest/gpio: add gpio test case

This test script try to do whitebox testing for gpio subsystem(based on
gpiolib). It manipulate gpio device through chardev or sysfs and check
the result from debugfs. This script test gpio-mockup through chardev by
default. User could test other gpio chip by passing the module name.
Some of the testcases are turned off by default to avoid the conflicting
with gpiochip in system.

In details, it test the following things:
1. Test direction and output value for valid pin.
2. Test dynamic allocation of gpio base.
3. Add single, multi gpiochip to do overlap check.

Run "tools/testing/selftests/gpio/gpio-mockup.sh -h" for usage.

Acked-by: Shuah Khan <[e-mail]>
Signed-off-by: Bamvor Jian Zhang <[e-mail]>
Signed-off-by: Shuah Khan <[e-mail]>

tools/testing/selftests/Makefile

···
 TARGETS += firmware
 TARGETS += ftrace
 TARGETS += futex
+TARGETS += gpio
 TARGETS += ipc
 TARGETS += kcmp
 TARGETS += lib

tools/testing/selftests/gpio/Makefile

···
+
+TEST_PROGS := gpio-mockup.sh
+TEST_FILES := gpio-mockup-sysfs.sh $(BINARIES)
+BINARIES := gpio-mockup-chardev
+
+include ../lib.mk
+
+all: $(BINARIES)
+
+clean:
+	$(RM) $(BINARIES)
+
+CFLAGS += -O2 -g -std=gnu99 -Wall -I../../../../usr/include/
+LDLIBS += -lmount -I/usr/include/libmount
+
+$(BINARIES): ../../../gpio/gpio-utils.o ../../../../usr/include/linux/gpio.h
+
+../../../gpio/gpio-utils.o:
+	make ARCH=$(ARCH) CROSS_COMPILE=$(CROSS_COMPILE) -C ../../../gpio
+
+../../../../usr/include/linux/gpio.h:
+	make -C ../../../.. headers_install INSTALL_HDR_PATH=$(shell pwd)/../../../../usr/
+

tools/testing/selftests/gpio/gpio-mockup-chardev.c

···
+/*
+ * GPIO chardev test helper
+ *
+ * Copyright (C) 2016 Bamvor Jian Zhang
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+#define _GNU_SOURCE
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <fcntl.h>
+#include <getopt.h>
+#include <sys/ioctl.h>
+#include <libmount.h>
+#include <err.h>
+#include <dirent.h>
+#include <linux/gpio.h>
+#include "../../../gpio/gpio-utils.h"
+
+#define CONSUMER	"gpio-selftest"
+#define	GC_NUM		10
+enum direction {
+	OUT,
+	IN
+};
+
+static int get_debugfs(char **path)
+{
+	struct libmnt_context *cxt;
+	struct libmnt_table *tb;
+	struct libmnt_iter *itr = NULL;
+	struct libmnt_fs *fs;
+	int found = 0;
+
+	cxt = mnt_new_context();
+	if (!cxt)
+		err(EXIT_FAILURE, "libmount context allocation failed");
+
+	itr = mnt_new_iter(MNT_ITER_FORWARD);
+	if (!itr)
+		err(EXIT_FAILURE, "failed to initialize libmount iterator");
+
+	if (mnt_context_get_mtab(cxt, &tb))
+		err(EXIT_FAILURE, "failed to read mtab");
+
+	while (mnt_table_next_fs(tb, itr, &fs) == 0) {
+		const char *type = mnt_fs_get_fstype(fs);
+
+		if (!strcmp(type, "debugfs")) {
+			found = 1;
+			break;
+		}
+	}
+	if (found)
+		asprintf(path, "%s/gpio", mnt_fs_get_target(fs));
+
+	mnt_free_iter(itr);
+	mnt_free_context(cxt);
+
+	if (!found)
+		return -1;
+
+	return 0;
+}
+
+static int gpio_debugfs_get(const char *consumer, int *dir, int *value)
+{
+	char *debugfs;
+	FILE *f;
+	char *line = NULL;
+	size_t len = 0;
+	char *cur;
+	int found = 0;
+
+	if (get_debugfs(&debugfs) != 0)
+		err(EXIT_FAILURE, "debugfs is not mounted");
+
+	f = fopen(debugfs, "r");
+	if (!f)
+		err(EXIT_FAILURE, "read from gpio debugfs failed");
+
+	/*
+	 * gpio-2   (                    |gpio-selftest               ) in  lo
+	 */
+	while (getline(&line, &len, f) != -1) {
+		cur = strstr(line, consumer);
+		if (cur == NULL)
+			continue;
+
+		cur = strchr(line, ')');
+		if (!cur)
+			continue;
+
+		cur += 2;
+		if (!strncmp(cur, "out", 3)) {
+			*dir = OUT;
+			cur += 4;
+		} else if (!strncmp(cur, "in", 2)) {
+			*dir = IN;
+			cur += 4;
+		}
+
+		if (!strncmp(cur, "hi", 2))
+			*value = 1;
+		else if (!strncmp(cur, "lo", 2))
+			*value = 0;
+
+		found = 1;
+		break;
+	}
+	free(debugfs);
+	fclose(f);
+	free(line);
+
+	if (!found)
+		return -1;
+
+	return 0;
+}
+
+static struct gpiochip_info *list_gpiochip(const char *gpiochip_name, int *ret)
+{
+	struct gpiochip_info *cinfo;
+	struct gpiochip_info *current;
+	const struct dirent *ent;
+	DIR *dp;
+	char *chrdev_name;
+	int fd;
+	int i = 0;
+
+	cinfo = calloc(sizeof(struct gpiochip_info) * 4, GC_NUM + 1);
+	if (!cinfo)
+		err(EXIT_FAILURE, "gpiochip_info allocation failed");
+
+	current = cinfo;
+	dp = opendir("/dev");
+	if (!dp) {
+		*ret = -errno;
+		goto error_out;
+	} else {
+		*ret = 0;
+	}
+
+	while (ent = readdir(dp), ent) {
+		if (check_prefix(ent->d_name, "gpiochip")) {
+			*ret = asprintf(&chrdev_name, "/dev/%s", ent->d_name);
+			if (*ret < 0)
+				goto error_out;
+
+			fd = open(chrdev_name, 0);
+			if (fd == -1) {
+				*ret = -errno;
+				fprintf(stderr, "Failed to open %s\n",
+					chrdev_name);
+				goto error_close_dir;
+			}
+			*ret = ioctl(fd, GPIO_GET_CHIPINFO_IOCTL, current);
+			if (*ret == -1) {
+				perror("Failed to issue CHIPINFO IOCTL\n");
+				goto error_close_dir;
+			}
+			close(fd);
+			if (strcmp(current->label, gpiochip_name) == 0
+			    || check_prefix(current->label, gpiochip_name)) {
+				*ret = 0;
+				current++;
+				i++;
+			}
+		}
+	}
+
+	if ((!*ret && i == 0) || *ret < 0) {
+		free(cinfo);
+		cinfo = NULL;
+	}
+	if (!*ret && i > 0) {
+		cinfo = realloc(cinfo, sizeof(struct gpiochip_info) * 4 * i);
+		*ret = i;
+	}
+
+error_close_dir:
+	closedir(dp);
+error_out:
+	if (*ret < 0)
+		err(EXIT_FAILURE, "list gpiochip failed: %s", strerror(*ret));
+
+	return cinfo;
+}
+
+int gpio_pin_test(struct gpiochip_info *cinfo, int line, int flag, int value)
+{
+	struct gpiohandle_data data;
+	unsigned int lines[] = {line};
+	int fd;
+	int debugfs_dir = IN;
+	int debugfs_value = 0;
+	int ret;
+
+	data.values[0] = value;
+	ret = gpiotools_request_linehandle(cinfo->name, lines, 1, flag, &data,
+					   CONSUMER);
+	if (ret < 0)
+		goto fail_out;
+	else
+		fd = ret;
+
+	ret = gpio_debugfs_get(CONSUMER, &debugfs_dir, &debugfs_value);
+	if (ret) {
+		ret = -EINVAL;
+		goto fail_out;
+	}
+	if (flag & GPIOHANDLE_REQUEST_INPUT) {
+		if (debugfs_dir != IN) {
+			errno = -EINVAL;
+			ret = -errno;
+		}
+	} else if (flag & GPIOHANDLE_REQUEST_OUTPUT) {
+		if (flag & GPIOHANDLE_REQUEST_ACTIVE_LOW)
+			debugfs_value = !debugfs_value;
+
+		if (!(debugfs_dir == OUT && value == debugfs_value))
+			errno = -EINVAL;
+		ret = -errno;
+
+	}
+	gpiotools_release_linehandle(fd);
+
+fail_out:
+	if (ret)
+		err(EXIT_FAILURE, "gpio<%s> line<%d> test flag<0x%x> value<%d>",
+		    cinfo->name, line, flag, value);
+
+	return ret;
+}
+
+void gpio_pin_tests(struct gpiochip_info *cinfo, unsigned int line)
+{
+	printf("line<%d>", line);
+	gpio_pin_test(cinfo, line, GPIOHANDLE_REQUEST_OUTPUT, 0);
+	printf(".");
+	gpio_pin_test(cinfo, line, GPIOHANDLE_REQUEST_OUTPUT, 1);
+	printf(".");
+	gpio_pin_test(cinfo, line,
+		      GPIOHANDLE_REQUEST_OUTPUT | GPIOHANDLE_REQUEST_ACTIVE_LOW,
+		      0);
+	printf(".");
+	gpio_pin_test(cinfo, line,
+		      GPIOHANDLE_REQUEST_OUTPUT | GPIOHANDLE_REQUEST_ACTIVE_LOW,
+		      1);
+	printf(".");
+	gpio_pin_test(cinfo, line, GPIOHANDLE_REQUEST_INPUT, 0);
+	printf(".");
+}
+
+/*
+ * ./gpio-mockup-chardev gpio_chip_name_prefix is_valid_gpio_chip
+ * Return 0 if successful or exit with EXIT_FAILURE if test failed.
+ * gpio_chip_name_prefix: The prefix of gpiochip you want to test. E.g.
+ *			  gpio-mockup
+ * is_valid_gpio_chip:	  Whether the gpio_chip is valid. 1 means valid,
+ *			  0 means invalid which could not be found by
+ *			  list_gpiochip.
+ */
+int main(int argc, char *argv[])
+{
+	char *prefix;
+	int valid;
+	struct gpiochip_info *cinfo;
+	struct gpiochip_info *current;
+	int i;
+	int ret;
+
+	if (argc < 3) {
+		printf("Usage: %s prefix is_valid", argv[0]);
+		exit(EXIT_FAILURE);
+	}
+
+	prefix = argv[1];
+	valid = strcmp(argv[2], "true") == 0 ? 1 : 0;
+
+	printf("Test gpiochip %s: ", prefix);
+	cinfo = list_gpiochip(prefix, &ret);
+	if (!cinfo) {
+		if (!valid && ret == 0) {
+			printf("Invalid test successful\n");
+			ret = 0;
+			goto out;
+		} else {
+			ret = -EINVAL;
+			goto out;
+		}
+	} else if (cinfo && !valid) {
+		ret = -EINVAL;
+		goto out;
+	}
+	current = cinfo;
+	for (i = 0; i < ret; i++) {
+		gpio_pin_tests(current, 0);
+		gpio_pin_tests(current, current->lines - 1);
+		gpio_pin_tests(current, random() % current->lines);
+		current++;
+	}
+	ret = 0;
+	printf("successful\n");
+
+out:
+	if (ret)
+		fprintf(stderr, "gpio<%s> test failed\n", prefix);
+
+	if (cinfo)
+		free(cinfo);
+
+	if (ret)
+		exit(EXIT_FAILURE);
+
+	return ret;
+}

tools/testing/selftests/gpio/gpio-mockup-sysfs.sh

···
+
+is_consistent()
+{
+	val=
+
+	active_low_sysfs=`cat $GPIO_SYSFS/gpio$nr/active_low`
+	val_sysfs=`cat $GPIO_SYSFS/gpio$nr/value`
+	dir_sysfs=`cat $GPIO_SYSFS/gpio$nr/direction`
+
+	gpio_this_debugfs=`cat $GPIO_DEBUGFS |grep "gpio-$nr" | sed "s/(.*)//g"`
+	dir_debugfs=`echo $gpio_this_debugfs | awk '{print $2}'`
+	val_debugfs=`echo $gpio_this_debugfs | awk '{print $3}'`
+	if [ $val_debugfs = "lo" ]; then
+		val=0
+	elif [ $val_debugfs = "hi" ]; then
+		val=1
+	fi
+
+	if [ $active_low_sysfs = "1" ]; then
+		if [ $val = "0" ]; then
+			val="1"
+		else
+			val="0"
+		fi
+	fi
+
+	if [ $val_sysfs = $val ] && [ $dir_sysfs = $dir_debugfs ]; then
+		echo -n "."
+	else
+		echo "test fail, exit"
+		die
+	fi
+}
+
+test_pin_logic()
+{
+	nr=$1
+	direction=$2
+	active_low=$3
+	value=$4
+
+	echo $direction > $GPIO_SYSFS/gpio$nr/direction
+	echo $active_low > $GPIO_SYSFS/gpio$nr/active_low
+	if [ $direction = "out" ]; then
+		echo $value > $GPIO_SYSFS/gpio$nr/value
+	fi
+	is_consistent $nr
+}
+
+test_one_pin()
+{
+	nr=$1
+
+	echo -n "test pin<$nr>"
+
+	echo $nr > $GPIO_SYSFS/export 2>/dev/null
+
+	if [ X$? != X0 ]; then
+		echo "test GPIO pin $nr failed"
+		die
+	fi
+
+	#"Checking if the sysfs is consistent with debugfs: "
+	is_consistent $nr
+
+	#"Checking the logic of active_low: "
+	test_pin_logic $nr out 1 1
+	test_pin_logic $nr out 1 0
+	test_pin_logic $nr out 0 1
+	test_pin_logic $nr out 0 0
+
+	#"Checking the logic of direction: "
+	test_pin_logic $nr in 1 1
+	test_pin_logic $nr out 1 0
+	test_pin_logic $nr low 0 1
+	test_pin_logic $nr high 0 0
+
+	echo $nr > $GPIO_SYSFS/unexport
+
+	echo "successful"
+}
+
+test_one_pin_fail()
+{
+	nr=$1
+
+	echo $nr > $GPIO_SYSFS/export 2>/dev/null
+
+	if [ X$? != X0 ]; then
+		echo "test invalid pin $nr successful"
+	else
+		echo "test invalid pin $nr failed"
+		echo $nr > $GPIO_SYSFS/unexport 2>/dev/null
+		die
+	fi
+}
+
+list_chip()
+{
+	echo `ls -d $GPIO_DRV_SYSFS/gpiochip* 2>/dev/null`
+}
+
+test_chip()
+{
+	chip=$1
+	name=`basename $chip`
+	base=`cat $chip/base`
+	ngpio=`cat $chip/ngpio`
+	printf "%-10s %-5s %-5s\n" $name $base $ngpio
+	if [ $ngpio = "0" ]; then
+		echo "number of gpio is zero is not allowed".
+	fi
+	test_one_pin $base
+	test_one_pin $(($base + $ngpio - 1))
+	test_one_pin $((( RANDOM % $ngpio )  + $base ))
+}
+
+test_chips_sysfs()
+{
+       gpiochip=`list_chip $module`
+       if [ X"$gpiochip" = X ]; then
+               if [ X"$valid" = Xfalse ]; then
+                       echo "successful"
+               else
+                       echo "fail"
+                       die
+               fi
+       else
+               for chip in $gpiochip; do
+                       test_chip $chip
+               done
+       fi
+}
+

tools/testing/selftests/gpio/gpio-mockup.sh

···
+#!/bin/bash
+
+#exit status
+#1: run as non-root user
+#2: sysfs/debugfs not mount
+#3: insert module fail when gpio-mockup is a module.
+#4: other reason.
+
+SYSFS=
+GPIO_SYSFS=
+GPIO_DRV_SYSFS=
+DEBUGFS=
+GPIO_DEBUGFS=
+dev_type=
+module=
+
+usage()
+{
+	echo "Usage:"
+	echo "$0 [-f] [-m name] [-t type]"
+	echo "-f:  full test. It maybe conflict with existence gpio device."
+	echo "-m:  module name, default name is gpio-mockup. It could also test"
+	echo "     other gpio device."
+	echo "-t:  interface type: chardev(char device) and sysfs(being"
+	echo "     deprecated). The first one is default"
+	echo ""
+	echo "$0 -h"
+	echo "This usage"
+}
+
+prerequisite()
+{
+	msg="skip all tests:"
+	if [ $UID != 0 ]; then
+		echo $msg must be run as root >&2
+		exit 1
+	fi
+	SYSFS=`mount -t sysfs | head -1 | awk '{ print $3 }'`
+	if [ ! -d "$SYSFS" ]; then
+		echo $msg sysfs is not mounted >&2
+		exit 2
+	fi
+	GPIO_SYSFS=`echo $SYSFS/class/gpio`
+	GPIO_DRV_SYSFS=`echo $SYSFS/devices/platform/$module/gpio`
+	DEBUGFS=`mount -t debugfs | head -1 | awk '{ print $3 }'`
+	if [ ! -d "$DEBUGFS" ]; then
+		echo $msg debugfs is not mounted >&2
+		exit 2
+	fi
+	GPIO_DEBUGFS=`echo $DEBUGFS/gpio`
+	source gpio-mockup-sysfs.sh
+}
+
+try_insert_module()
+{
+	if [ -d "$GPIO_DRV_SYSFS" ]; then
+		echo "$GPIO_DRV_SYSFS exist. Skip insert module"
+	else
+		modprobe -q $module $1
+		if [ X$? != X0 ]; then
+			echo $msg insmod $module failed >&2
+			exit 3
+		fi
+	fi
+}
+
+remove_module()
+{
+	modprobe -r -q $module
+}
+
+die()
+{
+	remove_module
+	exit 4
+}
+
+test_chips()
+{
+	if [ X$dev_type = Xsysfs ]; then
+		echo "WARNING: sysfs ABI of gpio is going to deprecated."
+		test_chips_sysfs $*
+	else
+		$BASE/gpio-mockup-chardev $*
+	fi
+}
+
+gpio_test()
+{
+	param=$1
+	valid=$2
+
+	if [ X"$param" = X ]; then
+		die
+	fi
+	try_insert_module "gpio_mockup_ranges=$param"
+	echo -n "GPIO $module test with ranges: <"
+	echo "$param>: "
+	printf "%-10s %s\n" $param
+	test_chips $module $valid
+	remove_module
+}
+
+BASE=`dirname $0`
+
+dev_type=
+TEMP=`getopt -o fhm:t: -n '$0' -- "$@"`
+
+if [ "$?" != "0" ]; then
+        echo "Parameter process failed, Terminating..." >&2
+        exit 1
+fi
+
+# Note the quotes around `$TEMP': they are essential!
+eval set -- "$TEMP"
+
+while true; do
+	case $1 in
+	-f)
+		full_test=true
+		shift
+		;;
+	-h)
+		usage
+		exit
+		;;
+	-m)
+		module=$2
+		shift 2
+		;;
+	-t)
+		dev_type=$2
+		shift 2
+		;;
+	--)
+		shift
+		break
+		;;
+	*)
+		echo "Internal error!"
+		exit 1
+		;;
+	esac
+done
+
+if [ X"$module" = X ]; then
+	module="gpio-mockup"
+fi
+
+if [ X$dev_type != Xsysfs ]; then
+	dev_type="chardev"
+fi
+
+prerequisite
+
+echo "1.  Test dynamic allocation of gpio successful means insert gpiochip and"
+echo "    manipulate gpio pin successful"
+gpio_test "-1,32" true
+gpio_test "-1,32,-1,32" true
+gpio_test "-1,32,-1,32,-1,32" true
+if [ X$full_test = Xtrue ]; then
+	gpio_test "-1,32,32,64" true
+	gpio_test "-1,32,40,64,-1,5" true
+	gpio_test "-1,32,32,64,-1,32" true
+	gpio_test "0,32,32,64,-1,32,-1,32" true
+	gpio_test "-1,32,-1,32,0,32,32,64" true
+	echo "2.  Do basic test: successful means insert gpiochip and"
+	echo "    manipulate gpio pin successful"
+	gpio_test "0,32" true
+	gpio_test "0,32,32,64" true
+	gpio_test "0,32,40,64,64,96" true
+fi
+echo "3.  Error test: successful means insert gpiochip failed"
+echo "3.1 Test number of gpio overflow"
+#Currently: The max number of gpio(1024) is defined in arm architecture.
+gpio_test "-1,32,-1,1024" false
+if [ X$full_test = Xtrue ]; then
+	echo "3.2 Test zero line of gpio"
+	gpio_test "0,0" false
+	echo "3.3 Test range overlap"
+	echo "3.3.1 Test corner case"
+	gpio_test "0,32,0,1" false
+	gpio_test "0,32,32,64,32,40" false
+	gpio_test "0,32,35,64,35,45" false
+	gpio_test "0,32,31,32" false
+	gpio_test "0,32,32,64,36,37" false
+	gpio_test "0,32,35,64,34,36" false
+	echo "3.3.2 Test inserting invalid second gpiochip"
+	gpio_test "0,32,30,35" false
+	gpio_test "0,32,1,5" false
+	gpio_test "10,32,9,14" false
+	gpio_test "10,32,30,35" false
+	echo "3.3.3 Test others"
+	gpio_test "0,32,40,56,39,45" false
+	gpio_test "0,32,40,56,30,33" false
+	gpio_test "0,32,40,56,30,41" false
+	gpio_test "0,32,40,56,20,21" false
+fi
+
+echo GPIO test PASS
+