// SPDX-License-Identifier: GPL-2.0-only
/* Industrialio buffer test code.
 *
 * Copyright (c) 2008 Jonathan Cameron
 *
 * This program is primarily intended as an example application.
 * Reads the current buffer setup from sysfs and starts a short capture
 * from the specified device, pretty printing the result after appropriate
 * conversion.
 *
 * Command line parameters
 * generic_buffer -n <device_name> -t <trigger_name>
 * If trigger name is not specified the program assumes you want a dataready
 * trigger associated with the device and goes looking for it.
 */

#include <unistd.h>
#include <stdlib.h>
#include <dirent.h>
#include <fcntl.h>
#include <stdio.h>
#include <errno.h>
#include <sys/stat.h>
#include <sys/dir.h>
#include <linux/types.h>
#include <string.h>
#include <poll.h>
#include <endian.h>
#include <getopt.h>
#include <inttypes.h>
#include <stdbool.h>
#include <signal.h>
#include <sys/ioctl.h>
#include <linux/iio/buffer.h>
#include "iio_utils.h"

/**
 * enum autochan - state for the automatic channel enabling mechanism
 */
enum autochan {
        AUTOCHANNELS_DISABLED,
        AUTOCHANNELS_ENABLED,
        AUTOCHANNELS_ACTIVE,
};

/**
 * size_from_channelarray() - calculate the storage size of a scan
 * @channels:           the channel info array
 * @num_channels:       number of channels
 *
 * Has the side effect of filling the channels[i].location values used
 * in processing the buffer output.
 **/
static unsigned int size_from_channelarray(struct iio_channel_info *channels, int num_channels)
{
        unsigned int bytes = 0;
        int i = 0, max = 0;
        unsigned int misalignment;

        while (i < num_channels) {
                if (channels[i].bytes > max)
                        max = channels[i].bytes;
                if (bytes % channels[i].bytes == 0)
                        channels[i].location = bytes;
                else
                        channels[i].location = bytes - bytes % channels[i].bytes
                                               + channels[i].bytes;

                bytes = channels[i].location + channels[i].bytes;
                i++;
        }
        /*
         * We want the data in next sample to also be properly aligned so
         * we'll add padding at the end if needed. Adding padding only
         * works for channel data which size is 2^n bytes.
         */
        misalignment = bytes % max;
        if (misalignment)
                bytes += max - misalignment;

        return bytes;
}

static void print1byte(uint8_t input, struct iio_channel_info *info)
{
        /*
         * Shift before conversion to avoid sign extension
         * of left aligned data
         */
        input >>= info->shift;
        input &= info->mask;
        if (info->is_signed) {
                int8_t val = (int8_t)(input << (8 - info->bits_used)) >>
                             (8 - info->bits_used);
                printf("%05f ", ((float)val + info->offset) * info->scale);
        } else {
                printf("%05f ", ((float)input + info->offset) * info->scale);
        }
}

static void print2byte(uint16_t input, struct iio_channel_info *info)
{
        /* First swap if incorrect endian */
        if (info->be)
                input = be16toh(input);
        else
                input = le16toh(input);

        /*
         * Shift before conversion to avoid sign extension
         * of left aligned data
         */
        input >>= info->shift;
        input &= info->mask;
        if (info->is_signed) {
                int16_t val = (int16_t)(input << (16 - info->bits_used)) >>
                              (16 - info->bits_used);
                printf("%05f ", ((float)val + info->offset) * info->scale);
        } else {
                printf("%05f ", ((float)input + info->offset) * info->scale);
        }
}

static void print4byte(uint32_t input, struct iio_channel_info *info)
{
        /* First swap if incorrect endian */
        if (info->be)
                input = be32toh(input);
        else
                input = le32toh(input);

        /*
         * Shift before conversion to avoid sign extension
         * of left aligned data
         */
        input >>= info->shift;
        input &= info->mask;
        if (info->is_signed) {
                int32_t val = (int32_t)(input << (32 - info->bits_used)) >>
                              (32 - info->bits_used);
                printf("%05f ", ((float)val + info->offset) * info->scale);
        } else {
                printf("%05f ", ((float)input + info->offset) * info->scale);
        }
}

static void print8byte(uint64_t input, struct iio_channel_info *info)
{
        /* First swap if incorrect endian */
        if (info->be)
                input = be64toh(input);
        else
                input = le64toh(input);

        /*
         * Shift before conversion to avoid sign extension
         * of left aligned data
         */
        input >>= info->shift;
        input &= info->mask;
        if (info->is_signed) {
                int64_t val = (int64_t)(input << (64 - info->bits_used)) >>
                              (64 - info->bits_used);
                /* special case for timestamp */
                if (info->scale == 1.0f && info->offset == 0.0f)
                        printf("%" PRId64 " ", val);
                else
                        printf("%05f ",
                               ((float)val + info->offset) * info->scale);
        } else {
                printf("%05f ", ((float)input + info->offset) * info->scale);
        }
}

/**
 * process_scan() - print out the values in SI units
 * @data:               pointer to the start of the scan
 * @channels:           information about the channels.
 *                      Note: size_from_channelarray must have been called first
 *                            to fill the location offsets.
 * @num_channels:       number of channels
 **/
static void process_scan(char *data, struct iio_channel_info *channels,
                         int num_channels)
{
        int k;

        for (k = 0; k < num_channels; k++)
                switch (channels[k].bytes) {
                        /* only a few cases implemented so far */
                case 1:
                        print1byte(*(uint8_t *)(data + channels[k].location),
                                   &channels[k]);
                        break;
                case 2:
                        print2byte(*(uint16_t *)(data + channels[k].location),
                                   &channels[k]);
                        break;
                case 4:
                        print4byte(*(uint32_t *)(data + channels[k].location),
                                   &channels[k]);
                        break;
                case 8:
                        print8byte(*(uint64_t *)(data + channels[k].location),
                                   &channels[k]);
                        break;
                default:
                        break;
                }
        printf("\n");
}

static int enable_disable_all_channels(char *dev_dir_name, int buffer_idx, int enable)
{
        const struct dirent *ent;
        char scanelemdir[256];
        DIR *dp;
        int ret;

        snprintf(scanelemdir, sizeof(scanelemdir),
                 FORMAT_SCAN_ELEMENTS_DIR, dev_dir_name, buffer_idx);
        scanelemdir[sizeof(scanelemdir)-1] = '\0';

        dp = opendir(scanelemdir);
        if (!dp) {
                fprintf(stderr, "Enabling/disabling channels: can't open %s\n",
                        scanelemdir);
                return -EIO;
        }

        ret = -ENOENT;
        while (ent = readdir(dp), ent) {
                if (iioutils_check_suffix(ent->d_name, "_en")) {
                        printf("%sabling: %s\n",
                               enable ? "En" : "Dis",
                               ent->d_name);
                        ret = write_sysfs_int(ent->d_name, scanelemdir,
                                              enable);
                        if (ret < 0)
                                fprintf(stderr, "Failed to enable/disable %s\n",
                                        ent->d_name);
                }
        }

        if (closedir(dp) == -1) {
                perror("Enabling/disabling channels: "
                       "Failed to close directory");
                return -errno;
        }
        return 0;
}

static void print_usage(void)
{
        fprintf(stderr, "Usage: generic_buffer [options]...\n"
                "Capture, convert and output data from IIO device buffer\n"
                "  -a         Auto-activate all available channels\n"
                "  -A         Force-activate ALL channels\n"
                "  -b <n>     The buffer which to open (by index), default 0\n"
                "  -c <n>     Do n conversions, or loop forever if n < 0\n"
                "  -e         Disable wait for event (new data)\n"
                "  -g         Use trigger-less mode\n"
                "  -l <n>     Set buffer length to n samples\n"
                "  --device-name -n <name>\n"
                "  --device-num -N <num>\n"
                "        Set device by name or number (mandatory)\n"
                "  --trigger-name -t <name>\n"
                "  --trigger-num -T <num>\n"
                "        Set trigger by name or number\n"
                "  -w <n>     Set delay between reads in us (event-less mode)\n");
}

static enum autochan autochannels = AUTOCHANNELS_DISABLED;
static char *dev_dir_name = NULL;
static char *buf_dir_name = NULL;
static int buffer_idx = 0;
static bool current_trigger_set = false;

static void cleanup(void)
{
        int ret;

        /* Disable trigger */
        if (dev_dir_name && current_trigger_set) {
                /* Disconnect the trigger - just write a dummy name. */
                ret = write_sysfs_string("trigger/current_trigger",
                                         dev_dir_name, "NULL");
                if (ret < 0)
                        fprintf(stderr, "Failed to disable trigger: %s\n",
                                strerror(-ret));
                current_trigger_set = false;
        }

        /* Disable buffer */
        if (buf_dir_name) {
                ret = write_sysfs_int("enable", buf_dir_name, 0);
                if (ret < 0)
                        fprintf(stderr, "Failed to disable buffer: %s\n",
                                strerror(-ret));
        }

        /* Disable channels if auto-enabled */
        if (dev_dir_name && autochannels == AUTOCHANNELS_ACTIVE) {
                ret = enable_disable_all_channels(dev_dir_name, buffer_idx, 0);
                if (ret)
                        fprintf(stderr, "Failed to disable all channels\n");
                autochannels = AUTOCHANNELS_DISABLED;
        }
}

static void sig_handler(int signum)
{
        fprintf(stderr, "Caught signal %d\n", signum);
        cleanup();
        exit(-signum);
}

static void register_cleanup(void)
{
        struct sigaction sa = { .sa_handler = sig_handler };
        const int signums[] = { SIGINT, SIGTERM, SIGABRT };
        int ret, i;

        for (i = 0; i < ARRAY_SIZE(signums); ++i) {
                ret = sigaction(signums[i], &sa, NULL);
                if (ret) {
                        perror("Failed to register signal handler");
                        exit(-1);
                }
        }
}

static const struct option longopts[] = {
        { "device-name",        1, 0, 'n' },
        { "device-num",         1, 0, 'N' },
        { "trigger-name",       1, 0, 't' },
        { "trigger-num",        1, 0, 'T' },
        { }
};

int main(int argc, char **argv)
{
        long long num_loops = 2;
        unsigned long timedelay = 1000000;
        unsigned long buf_len = 128;

        ssize_t i;
        unsigned long long j;
        unsigned long toread;
        int ret, c;
        struct stat st;
        int fd = -1;
        int buf_fd = -1;

        int num_channels = 0;
        char *trigger_name = NULL, *device_name = NULL;

        char *data = NULL;
        ssize_t read_size;
        int dev_num = -1, trig_num = -1;
        char *buffer_access = NULL;
        unsigned int scan_size;
        int noevents = 0;
        int notrigger = 0;
        char *dummy;
        bool force_autochannels = false;

        struct iio_channel_info *channels = NULL;

        register_cleanup();

        while ((c = getopt_long(argc, argv, "aAb:c:egl:n:N:t:T:w:?", longopts,
                                NULL)) != -1) {
                switch (c) {
                case 'a':
                        autochannels = AUTOCHANNELS_ENABLED;
                        break;
                case 'A':
                        autochannels = AUTOCHANNELS_ENABLED;
                        force_autochannels = true;
                        break;
                case 'b':
                        errno = 0;
                        buffer_idx = strtoll(optarg, &dummy, 10);
                        if (errno) {
                                ret = -errno;
                                goto error;
                        }
                        if (buffer_idx < 0) {
                                ret = -ERANGE;
                                goto error;
                        }

                        break;
                case 'c':
                        errno = 0;
                        num_loops = strtoll(optarg, &dummy, 10);
                        if (errno) {
                                ret = -errno;
                                goto error;
                        }

                        break;
                case 'e':
                        noevents = 1;
                        break;
                case 'g':
                        notrigger = 1;
                        break;
                case 'l':
                        errno = 0;
                        buf_len = strtoul(optarg, &dummy, 10);
                        if (errno) {
                                ret = -errno;
                                goto error;
                        }

                        break;
                case 'n':
                        device_name = strdup(optarg);
                        break;
                case 'N':
                        errno = 0;
                        dev_num = strtoul(optarg, &dummy, 10);
                        if (errno) {
                                ret = -errno;
                                goto error;
                        }
                        break;
                case 't':
                        trigger_name = strdup(optarg);
                        break;
                case 'T':
                        errno = 0;
                        trig_num = strtoul(optarg, &dummy, 10);
                        if (errno)
                                return -errno;
                        break;
                case 'w':
                        errno = 0;
                        timedelay = strtoul(optarg, &dummy, 10);
                        if (errno) {
                                ret = -errno;
                                goto error;
                        }
                        break;
                case '?':
                        print_usage();
                        ret = -1;
                        goto error;
                }
        }

        /* Find the device requested */
        if (dev_num < 0 && !device_name) {
                fprintf(stderr, "Device not set\n");
                print_usage();
                ret = -1;
                goto error;
        } else if (dev_num >= 0 && device_name) {
                fprintf(stderr, "Only one of --device-num or --device-name needs to be set\n");
                print_usage();
                ret = -1;
                goto error;
        } else if (dev_num < 0) {
                dev_num = find_type_by_name(device_name, "iio:device");
                if (dev_num < 0) {
                        fprintf(stderr, "Failed to find the %s\n", device_name);
                        ret = dev_num;
                        goto error;
                }
        }
        printf("iio device number being used is %d\n", dev_num);

        ret = asprintf(&dev_dir_name, "%siio:device%d", iio_dir, dev_num);
        if (ret < 0)
                return -ENOMEM;
        /* Fetch device_name if specified by number */
        if (!device_name) {
                device_name = malloc(IIO_MAX_NAME_LENGTH);
                if (!device_name) {
                        ret = -ENOMEM;
                        goto error;
                }
                ret = read_sysfs_string("name", dev_dir_name, device_name);
                if (ret < 0) {
                        fprintf(stderr, "Failed to read name of device %d\n", dev_num);
                        goto error;
                }
        }

        if (notrigger) {
                printf("trigger-less mode selected\n");
        } else if (trig_num >= 0) {
                char *trig_dev_name;
                ret = asprintf(&trig_dev_name, "%strigger%d", iio_dir, trig_num);
                if (ret < 0) {
                        return -ENOMEM;
                }
                trigger_name = malloc(IIO_MAX_NAME_LENGTH);
                if (!trigger_name) {
                        ret = -ENOMEM;
                        goto error;
                }
                ret = read_sysfs_string("name", trig_dev_name, trigger_name);
                free(trig_dev_name);
                if (ret < 0) {
                        fprintf(stderr, "Failed to read trigger%d name from\n", trig_num);
                        return ret;
                }
                printf("iio trigger number being used is %d\n", trig_num);
        } else {
                if (!trigger_name) {
                        /*
                         * Build the trigger name. If it is device associated
                         * its name is <device_name>_dev[n] where n matches
                         * the device number found above.
                         */
                        ret = asprintf(&trigger_name,
                                       "%s-dev%d", device_name, dev_num);
                        if (ret < 0) {
                                ret = -ENOMEM;
                                goto error;
                        }
                }

                /* Look for this "-devN" trigger */
                trig_num = find_type_by_name(trigger_name, "trigger");
                if (trig_num < 0) {
                        /* OK try the simpler "-trigger" suffix instead */
                        free(trigger_name);
                        ret = asprintf(&trigger_name,
                                       "%s-trigger", device_name);
                        if (ret < 0) {
                                ret = -ENOMEM;
                                goto error;
                        }
                }

                trig_num = find_type_by_name(trigger_name, "trigger");
                if (trig_num < 0) {
                        fprintf(stderr, "Failed to find the trigger %s\n",
                                trigger_name);
                        ret = trig_num;
                        goto error;
                }

                printf("iio trigger number being used is %d\n", trig_num);
        }

        /*
         * Parse the files in scan_elements to identify what channels are
         * present
         */
        ret = build_channel_array(dev_dir_name, buffer_idx, &channels, &num_channels);
        if (ret) {
                fprintf(stderr, "Problem reading scan element information\n"
                        "diag %s\n", dev_dir_name);
                goto error;
        }
        if (num_channels && autochannels == AUTOCHANNELS_ENABLED &&
            !force_autochannels) {
                fprintf(stderr, "Auto-channels selected but some channels "
                        "are already activated in sysfs\n");
                fprintf(stderr, "Proceeding without activating any channels\n");
        }

        if ((!num_channels && autochannels == AUTOCHANNELS_ENABLED) ||
            (autochannels == AUTOCHANNELS_ENABLED && force_autochannels)) {
                fprintf(stderr, "Enabling all channels\n");

                ret = enable_disable_all_channels(dev_dir_name, buffer_idx, 1);
                if (ret) {
                        fprintf(stderr, "Failed to enable all channels\n");
                        goto error;
                }

                /* This flags that we need to disable the channels again */
                autochannels = AUTOCHANNELS_ACTIVE;

                ret = build_channel_array(dev_dir_name, buffer_idx, &channels,
                                          &num_channels);
                if (ret) {
                        fprintf(stderr, "Problem reading scan element "
                                "information\n"
                                "diag %s\n", dev_dir_name);
                        goto error;
                }
                if (!num_channels) {
                        fprintf(stderr, "Still no channels after "
                                "auto-enabling, giving up\n");
                        goto error;
                }
        }

        if (!num_channels && autochannels == AUTOCHANNELS_DISABLED) {
                fprintf(stderr,
                        "No channels are enabled, we have nothing to scan.\n");
                fprintf(stderr, "Enable channels manually in "
                        FORMAT_SCAN_ELEMENTS_DIR
                        "/*_en or pass -a to autoenable channels and "
                        "try again.\n", dev_dir_name, buffer_idx);
                ret = -ENOENT;
                goto error;
        }

        /*
         * Construct the directory name for the associated buffer.
         * As we know that the lis3l02dq has only one buffer this may
         * be built rather than found.
         */
        ret = asprintf(&buf_dir_name,
                       "%siio:device%d/buffer%d", iio_dir, dev_num, buffer_idx);
        if (ret < 0) {
                ret = -ENOMEM;
                goto error;
        }

        if (stat(buf_dir_name, &st)) {
                fprintf(stderr, "Could not stat() '%s', got error %d: %s\n",
                        buf_dir_name, errno, strerror(errno));
                ret = -errno;
                goto error;
        }

        if (!S_ISDIR(st.st_mode)) {
                fprintf(stderr, "File '%s' is not a directory\n", buf_dir_name);
                ret = -EFAULT;
                goto error;
        }

        if (!notrigger) {
                printf("%s %s\n", dev_dir_name, trigger_name);
                /*
                 * Set the device trigger to be the data ready trigger found
                 * above
                 */
                ret = write_sysfs_string_and_verify("trigger/current_trigger",
                                                    dev_dir_name,
                                                    trigger_name);
                if (ret < 0) {
                        fprintf(stderr,
                                "Failed to write current_trigger file\n");
                        goto error;
                }
        }

        ret = asprintf(&buffer_access, "/dev/iio:device%d", dev_num);
        if (ret < 0) {
                ret = -ENOMEM;
                goto error;
        }

        /* Attempt to open non blocking the access dev */
        fd = open(buffer_access, O_RDONLY | O_NONBLOCK);
        if (fd == -1) { /* TODO: If it isn't there make the node */
                ret = -errno;
                fprintf(stderr, "Failed to open %s\n", buffer_access);
                goto error;
        }

        /* specify for which buffer index we want an FD */
        buf_fd = buffer_idx;

        ret = ioctl(fd, IIO_BUFFER_GET_FD_IOCTL, &buf_fd);
        if (ret == -1 || buf_fd == -1) {
                ret = -errno;
                if (ret == -ENODEV || ret == -EINVAL)
                        fprintf(stderr,
                                "Device does not have this many buffers\n");
                else
                        fprintf(stderr, "Failed to retrieve buffer fd\n");

                goto error;
        }

        /* Setup ring buffer parameters */
        ret = write_sysfs_int("length", buf_dir_name, buf_len);
        if (ret < 0)
                goto error;

        /* Enable the buffer */
        ret = write_sysfs_int("enable", buf_dir_name, 1);
        if (ret < 0) {
                fprintf(stderr,
                        "Failed to enable buffer '%s': %s\n",
                        buf_dir_name, strerror(-ret));
                goto error;
        }

        scan_size = size_from_channelarray(channels, num_channels);

        size_t total_buf_len = scan_size * buf_len;

        if (scan_size > 0 && total_buf_len / scan_size != buf_len) {
                ret = -EFAULT;
                perror("Integer overflow happened when calculate scan_size * buf_len");
                goto error;
        }

        data = malloc(total_buf_len);
        if (!data) {
                ret = -ENOMEM;
                goto error;
        }

        /**
         * This check is being done here for sanity reasons, however it
         * should be omitted under normal operation.
         * If this is buffer0, we check that we get EBUSY after this point.
         */
        if (buffer_idx == 0) {
                errno = 0;
                read_size = read(fd, data, 1);
                if (read_size > -1 || errno != EBUSY) {
                        ret = -EFAULT;
                        perror("Reading from '%s' should not be possible after ioctl()");
                        goto error;
                }
        }

        /* close now the main chardev FD and let the buffer FD work */
        if (close(fd) == -1)
                perror("Failed to close character device file");
        fd = -1;

        for (j = 0; j < num_loops || num_loops < 0; j++) {
                if (!noevents) {
                        struct pollfd pfd = {
                                .fd = buf_fd,
                                .events = POLLIN,
                        };

                        ret = poll(&pfd, 1, -1);
                        if (ret < 0) {
                                ret = -errno;
                                goto error;
                        } else if (ret == 0) {
                                continue;
                        }

                } else {
                        usleep(timedelay);
                }

                toread = buf_len;

                read_size = read(buf_fd, data, toread * scan_size);
                if (read_size < 0) {
                        if (errno == EAGAIN) {
                                fprintf(stderr, "nothing available\n");
                                continue;
                        } else {
                                break;
                        }
                }
                for (i = 0; i < read_size / scan_size; i++)
                        process_scan(data + scan_size * i, channels,
                                     num_channels);
        }

error:
        cleanup();

        if (fd >= 0 && close(fd) == -1)
                perror("Failed to close character device");
        if (buf_fd >= 0 && close(buf_fd) == -1)
                perror("Failed to close buffer");
        free(buffer_access);
        free(data);
        free(buf_dir_name);
        for (i = num_channels - 1; i >= 0; i--) {
                free(channels[i].name);
                free(channels[i].generic_name);
        }
        free(channels);
        free(trigger_name);
        free(device_name);
        free(dev_dir_name);

        return ret;
}