/* Industrialio buffer test code.
 *
 * Copyright (c) 2008 Jonathan Cameron
 *
 * 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.
 *
 * 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 "iio_utils.h"

/**
 * 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.
 **/
int size_from_channelarray(struct iio_channel_info *channels, int num_channels)
{
        int bytes = 0;
        int i = 0;

        while (i < num_channels) {
                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++;
        }

        return bytes;
}

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);
        }
}

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);
        }
}

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);
        }
}

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
 **/
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");
}

void print_usage(void)
{
        fprintf(stderr, "Usage: generic_buffer [options]...\n"
                "Capture, convert and output data from IIO device buffer\n"
                "  -c <n>     Do n conversions\n"
                "  -e         Disable wait for event (new data)\n"
                "  -g         Use trigger-less mode\n"
                "  -l <n>     Set buffer length to n samples\n"
                "  -n <name>  Set device name (mandatory)\n"
                "  -t <name>  Set trigger name\n"
                "  -w <n>     Set delay between reads in us (event-less mode)\n");
}

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

        int ret, c, i, j, toread;
        int fp;

        int num_channels;
        char *trigger_name = NULL, *device_name = NULL;
        char *dev_dir_name, *buf_dir_name;

        int datardytrigger = 1;
        char *data;
        ssize_t read_size;
        int dev_num, trig_num;
        char *buffer_access;
        int scan_size;
        int noevents = 0;
        int notrigger = 0;
        char *dummy;

        struct iio_channel_info *channels;

        while ((c = getopt(argc, argv, "c:egl:n:t:w:")) != -1) {
                switch (c) {
                case 'c':
                        errno = 0;
                        num_loops = strtoul(optarg, &dummy, 10);
                        if (errno)
                                return -errno;

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

                        break;
                case 'n':
                        device_name = optarg;
                        break;
                case 't':
                        trigger_name = optarg;
                        datardytrigger = 0;
                        break;
                case 'w':
                        errno = 0;
                        timedelay = strtoul(optarg, &dummy, 10);
                        if (errno)
                                return -errno;
                        break;
                case '?':
                        print_usage();
                        return -1;
                }
        }

        if (!device_name) {
                fprintf(stderr, "Device name not set\n");
                print_usage();
                return -1;
        }

        /* Find the device requested */
        dev_num = find_type_by_name(device_name, "iio:device");
        if (dev_num < 0) {
                fprintf(stderr, "Failed to find the %s\n", device_name);
                return dev_num;
        }

        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;

        if (!notrigger) {
                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_free_dev_dir_name;
                        }
                }

                /* Verify the trigger exists */
                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_free_triggername;
                }

                printf("iio trigger number being used is %d\n", trig_num);
        } else {
                printf("trigger-less mode selected\n");
        }

        /*
         * Parse the files in scan_elements to identify what channels are
         * present
         */
        ret = build_channel_array(dev_dir_name, &channels, &num_channels);
        if (ret) {
                fprintf(stderr, "Problem reading scan element information\n"
                        "diag %s\n", dev_dir_name);
                goto error_free_triggername;
        }
        if (!num_channels) {
                fprintf(stderr,
                        "No channels are enabled, we have nothing to scan.\n");
                fprintf(stderr, "Enable channels manually in "
                        FORMAT_SCAN_ELEMENTS_DIR
                        "/*_en and try again.\n", dev_dir_name);
                ret = -ENOENT;
                goto error_free_triggername;
        }

        /*
         * 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", iio_dir, dev_num);
        if (ret < 0) {
                ret = -ENOMEM;
                goto error_free_channels;
        }

        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_free_buf_dir_name;
                }
        }

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

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

        scan_size = size_from_channelarray(channels, num_channels);
        data = malloc(scan_size * buf_len);
        if (!data) {
                ret = -ENOMEM;
                goto error_free_buf_dir_name;
        }

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

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

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

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

                        toread = buf_len;
                } else {
                        usleep(timedelay);
                        toread = 64;
                }

                read_size = read(fp, 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);
        }

        /* Stop the buffer */
        ret = write_sysfs_int("enable", buf_dir_name, 0);
        if (ret < 0)
                goto error_close_buffer_access;

        if (!notrigger)
                /* 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 write to %s\n",
                                dev_dir_name);

error_close_buffer_access:
        if (close(fp) == -1)
                perror("Failed to close buffer");

error_free_buffer_access:
        free(buffer_access);
error_free_data:
        free(data);
error_free_buf_dir_name:
        free(buf_dir_name);
error_free_channels:
        for (i = num_channels - 1; i >= 0; i--) {
                free(channels[i].name);
                free(channels[i].generic_name);
        }
        free(channels);
error_free_triggername:
        if (datardytrigger)
                free(trigger_name);

error_free_dev_dir_name:
        free(dev_dir_name);

        return ret;
}