// SPDX-License-Identifier: GPL-2.0+
/* speakup_soft.c - speakup driver to register and make available
 * a user space device for software synthesizers.  written by: Kirk
 * Reiser <kirk@braille.uwo.ca>
 *
 * Copyright (C) 2003  Kirk Reiser.
 *
 * this code is specifically written as a driver for the speakup screenreview
 * package and is not a general device driver.
 */

#include <linux/unistd.h>
#include <linux/miscdevice.h>   /* for misc_register, and MISC_DYNAMIC_MINOR */
#include <linux/poll.h>         /* for poll_wait() */

/* schedule(), signal_pending(), TASK_INTERRUPTIBLE */
#include <linux/sched/signal.h>

#include "spk_priv.h"
#include "speakup.h"

#define DRV_VERSION "2.6"
#define PROCSPEECH 0x0d
#define CLEAR_SYNTH 0x18

static int softsynth_probe(struct spk_synth *synth);
static void softsynth_release(struct spk_synth *synth);
static int softsynth_is_alive(struct spk_synth *synth);
static int softsynth_adjust(struct spk_synth *synth, struct st_var_header *var);
static unsigned char get_index(struct spk_synth *synth);

static struct miscdevice synth_device, synthu_device;
static int init_pos;
static int misc_registered;


enum default_vars_id {
        DIRECT_ID = 0, CAPS_START_ID, CAPS_STOP_ID,
        PAUSE_ID, RATE_ID, PITCH_ID, INFLECTION_ID,
        VOL_ID, TONE_ID, PUNCT_ID, VOICE_ID,
        FREQUENCY_ID, V_LAST_VAR_ID,
         NB_ID
};


static struct var_t vars[NB_ID] = {

        [DIRECT_ID]  = { DIRECT, .u.n = {NULL, 0, 0, 1, 0, 0, NULL } },
        [CAPS_START_ID] = { CAPS_START, .u.s = {"\x01+3p" } },
        [CAPS_STOP_ID]  = { CAPS_STOP, .u.s = {"\x01-3p" } },
        [PAUSE_ID]  = { PAUSE, .u.n = {"\x01P" } },
        [RATE_ID]  = { RATE, .u.n = {"\x01%ds", 2, 0, 9, 0, 0, NULL } },
        [PITCH_ID]  = { PITCH, .u.n = {"\x01%dp", 5, 0, 9, 0, 0, NULL } },
        [INFLECTION_ID]  = { INFLECTION, .u.n = {"\x01%dr", 5, 0, 9, 0, 0, NULL } },
        [VOL_ID]  = { VOL, .u.n = {"\x01%dv", 5, 0, 9, 0, 0, NULL } },
        [TONE_ID]  = { TONE, .u.n = {"\x01%dx", 1, 0, 2, 0, 0, NULL } },
        [PUNCT_ID]  = { PUNCT, .u.n = {"\x01%db", 0, 0, 3, 0, 0, NULL } },
        [VOICE_ID]  = { VOICE, .u.n = {"\x01%do", 0, 0, 7, 0, 0, NULL } },
        [FREQUENCY_ID]  = { FREQUENCY, .u.n = {"\x01%df", 5, 0, 9, 0, 0, NULL } },
        V_LAST_VAR
};

/* These attributes will appear in /sys/accessibility/speakup/soft. */

static struct kobj_attribute caps_start_attribute =
        __ATTR(caps_start, 0644, spk_var_show, spk_var_store);
static struct kobj_attribute caps_stop_attribute =
        __ATTR(caps_stop, 0644, spk_var_show, spk_var_store);
static struct kobj_attribute freq_attribute =
        __ATTR(freq, 0644, spk_var_show, spk_var_store);
static struct kobj_attribute pitch_attribute =
        __ATTR(pitch, 0644, spk_var_show, spk_var_store);
static struct kobj_attribute inflection_attribute =
        __ATTR(inflection, 0644, spk_var_show, spk_var_store);
static struct kobj_attribute punct_attribute =
        __ATTR(punct, 0644, spk_var_show, spk_var_store);
static struct kobj_attribute rate_attribute =
        __ATTR(rate, 0644, spk_var_show, spk_var_store);
static struct kobj_attribute tone_attribute =
        __ATTR(tone, 0644, spk_var_show, spk_var_store);
static struct kobj_attribute voice_attribute =
        __ATTR(voice, 0644, spk_var_show, spk_var_store);
static struct kobj_attribute vol_attribute =
        __ATTR(vol, 0644, spk_var_show, spk_var_store);

/*
 * We should uncomment the following definition, when we agree on a
 * method of passing a language designation to the software synthesizer.
 * static struct kobj_attribute lang_attribute =
 *      __ATTR(lang, 0644, spk_var_show, spk_var_store);
 */

static struct kobj_attribute delay_time_attribute =
        __ATTR(delay_time, 0644, spk_var_show, spk_var_store);
static struct kobj_attribute direct_attribute =
        __ATTR(direct, 0644, spk_var_show, spk_var_store);
static struct kobj_attribute full_time_attribute =
        __ATTR(full_time, 0644, spk_var_show, spk_var_store);
static struct kobj_attribute jiffy_delta_attribute =
        __ATTR(jiffy_delta, 0644, spk_var_show, spk_var_store);
static struct kobj_attribute trigger_time_attribute =
        __ATTR(trigger_time, 0644, spk_var_show, spk_var_store);

/*
 * Create a group of attributes so that we can create and destroy them all
 * at once.
 */
static struct attribute *synth_attrs[] = {
        &caps_start_attribute.attr,
        &caps_stop_attribute.attr,
        &freq_attribute.attr,
/*      &lang_attribute.attr, */
        &pitch_attribute.attr,
        &inflection_attribute.attr,
        &punct_attribute.attr,
        &rate_attribute.attr,
        &tone_attribute.attr,
        &voice_attribute.attr,
        &vol_attribute.attr,
        &delay_time_attribute.attr,
        &direct_attribute.attr,
        &full_time_attribute.attr,
        &jiffy_delta_attribute.attr,
        &trigger_time_attribute.attr,
        NULL,   /* need to NULL terminate the list of attributes */
};

static struct spk_synth synth_soft = {
        .name = "soft",
        .version = DRV_VERSION,
        .long_name = "software synth",
        .init = "\01@\x01\x31y\n",
        .procspeech = PROCSPEECH,
        .delay = 0,
        .trigger = 0,
        .jiffies = 0,
        .full = 0,
        .startup = SYNTH_START,
        .checkval = SYNTH_CHECK,
        .vars = vars,
        .io_ops = NULL,
        .probe = softsynth_probe,
        .release = softsynth_release,
        .synth_immediate = NULL,
        .catch_up = NULL,
        .flush = NULL,
        .is_alive = softsynth_is_alive,
        .synth_adjust = softsynth_adjust,
        .read_buff_add = NULL,
        .get_index = get_index,
        .indexing = {
                .command = "\x01%di",
                .lowindex = 1,
                .highindex = 5,
                .currindex = 1,
        },
        .attributes = {
                .attrs = synth_attrs,
                .name = "soft",
        },
};

static char *get_initstring(void)
{
        static char buf[40];
        char *cp;
        struct var_t *var;
        size_t len;
        size_t n;

        memset(buf, 0, sizeof(buf));
        cp = buf;
        len = sizeof(buf);

        var = synth_soft.vars;
        while (var->var_id != MAXVARS) {
                if (var->var_id != CAPS_START && var->var_id != CAPS_STOP &&
                    var->var_id != PAUSE && var->var_id != DIRECT) {
                        n = scnprintf(cp, len, var->u.n.synth_fmt,
                                      var->u.n.value);
                        cp = cp + n;
                        len = len - n;
                }
                var++;
        }
        cp = cp + scnprintf(cp, len, "\n");
        return buf;
}

static int softsynth_open(struct inode *inode, struct file *fp)
{
        unsigned long flags;
        /*if ((fp->f_flags & O_ACCMODE) != O_RDONLY) */
        /*      return -EPERM; */
        spin_lock_irqsave(&speakup_info.spinlock, flags);
        if (synth_soft.alive) {
                spin_unlock_irqrestore(&speakup_info.spinlock, flags);
                return -EBUSY;
        }
        synth_soft.alive = 1;
        spin_unlock_irqrestore(&speakup_info.spinlock, flags);
        return 0;
}

static int softsynth_close(struct inode *inode, struct file *fp)
{
        unsigned long flags;

        spin_lock_irqsave(&speakup_info.spinlock, flags);
        synth_soft.alive = 0;
        init_pos = 0;
        spin_unlock_irqrestore(&speakup_info.spinlock, flags);
        /* Make sure we let applications go before leaving */
        speakup_start_ttys();
        return 0;
}

static ssize_t softsynthx_read(struct file *fp, char __user *buf, size_t count,
                               loff_t *pos, int unicode)
{
        int chars_sent = 0;
        char __user *cp;
        char *init;
        size_t bytes_per_ch = unicode ? 3 : 1;
        u16 ch;
        int empty;
        unsigned long flags;
        DEFINE_WAIT(wait);

        if (count < bytes_per_ch)
                return -EINVAL;

        spin_lock_irqsave(&speakup_info.spinlock, flags);
        synth_soft.alive = 1;
        while (1) {
                prepare_to_wait(&speakup_event, &wait, TASK_INTERRUPTIBLE);
                if (synth_current() == &synth_soft) {
                        if (!unicode)
                                synth_buffer_skip_nonlatin1();
                        if (!synth_buffer_empty() || speakup_info.flushing)
                                break;
                }
                spin_unlock_irqrestore(&speakup_info.spinlock, flags);
                if (fp->f_flags & O_NONBLOCK) {
                        finish_wait(&speakup_event, &wait);
                        return -EAGAIN;
                }
                if (signal_pending(current)) {
                        finish_wait(&speakup_event, &wait);
                        return -ERESTARTSYS;
                }
                schedule();
                spin_lock_irqsave(&speakup_info.spinlock, flags);
        }
        finish_wait(&speakup_event, &wait);

        cp = buf;
        init = get_initstring();

        /* Keep 3 bytes available for a 16bit UTF-8-encoded character */
        while (chars_sent <= count - bytes_per_ch) {
                if (synth_current() != &synth_soft)
                        break;
                if (speakup_info.flushing) {
                        speakup_info.flushing = 0;
                        ch = '\x18';
                } else if (init[init_pos]) {
                        ch = init[init_pos++];
                } else {
                        if (!unicode)
                                synth_buffer_skip_nonlatin1();
                        if (synth_buffer_empty())
                                break;
                        ch = synth_buffer_getc();
                }
                spin_unlock_irqrestore(&speakup_info.spinlock, flags);

                if ((!unicode && ch < 0x100) || (unicode && ch < 0x80)) {
                        u_char c = ch;

                        if (copy_to_user(cp, &c, 1))
                                return -EFAULT;

                        chars_sent++;
                        cp++;
                } else if (unicode && ch < 0x800) {
                        u_char s[2] = {
                                0xc0 | (ch >> 6),
                                0x80 | (ch & 0x3f)
                        };

                        if (copy_to_user(cp, s, sizeof(s)))
                                return -EFAULT;

                        chars_sent += sizeof(s);
                        cp += sizeof(s);
                } else if (unicode) {
                        u_char s[3] = {
                                0xe0 | (ch >> 12),
                                0x80 | ((ch >> 6) & 0x3f),
                                0x80 | (ch & 0x3f)
                        };

                        if (copy_to_user(cp, s, sizeof(s)))
                                return -EFAULT;

                        chars_sent += sizeof(s);
                        cp += sizeof(s);
                }

                spin_lock_irqsave(&speakup_info.spinlock, flags);
        }
        *pos += chars_sent;
        empty = synth_buffer_empty();
        spin_unlock_irqrestore(&speakup_info.spinlock, flags);
        if (empty) {
                speakup_start_ttys();
                *pos = 0;
        }
        return chars_sent;
}

static ssize_t softsynth_read(struct file *fp, char __user *buf, size_t count,
                              loff_t *pos)
{
        return softsynthx_read(fp, buf, count, pos, 0);
}

static ssize_t softsynthu_read(struct file *fp, char __user *buf, size_t count,
                               loff_t *pos)
{
        return softsynthx_read(fp, buf, count, pos, 1);
}

static int last_index;

static ssize_t softsynth_write(struct file *fp, const char __user *buf,
                               size_t count, loff_t *pos)
{
        unsigned long supplied_index = 0;
        int converted;

        converted = kstrtoul_from_user(buf, count, 0, &supplied_index);

        if (converted < 0)
                return converted;

        last_index = supplied_index;
        return count;
}

static __poll_t softsynth_poll(struct file *fp, struct poll_table_struct *wait)
{
        unsigned long flags;
        __poll_t ret = 0;

        poll_wait(fp, &speakup_event, wait);

        spin_lock_irqsave(&speakup_info.spinlock, flags);
        if (synth_current() == &synth_soft &&
            (!synth_buffer_empty() || speakup_info.flushing))
                ret = EPOLLIN | EPOLLRDNORM;
        spin_unlock_irqrestore(&speakup_info.spinlock, flags);
        return ret;
}

static unsigned char get_index(struct spk_synth *synth)
{
        int rv;

        rv = last_index;
        last_index = 0;
        return rv;
}

static const struct file_operations softsynth_fops = {
        .owner = THIS_MODULE,
        .poll = softsynth_poll,
        .read = softsynth_read,
        .write = softsynth_write,
        .open = softsynth_open,
        .release = softsynth_close,
};

static const struct file_operations softsynthu_fops = {
        .owner = THIS_MODULE,
        .poll = softsynth_poll,
        .read = softsynthu_read,
        .write = softsynth_write,
        .open = softsynth_open,
        .release = softsynth_close,
};

static int softsynth_probe(struct spk_synth *synth)
{
        if (misc_registered != 0)
                return 0;
        memset(&synth_device, 0, sizeof(synth_device));
        synth_device.minor = MISC_DYNAMIC_MINOR;
        synth_device.name = "softsynth";
        synth_device.fops = &softsynth_fops;
        if (misc_register(&synth_device)) {
                pr_warn("Couldn't initialize miscdevice /dev/softsynth.\n");
                return -ENODEV;
        }

        memset(&synthu_device, 0, sizeof(synthu_device));
        synthu_device.minor = MISC_DYNAMIC_MINOR;
        synthu_device.name = "softsynthu";
        synthu_device.fops = &softsynthu_fops;
        if (misc_register(&synthu_device)) {
                misc_deregister(&synth_device);
                pr_warn("Couldn't initialize miscdevice /dev/softsynthu.\n");
                return -ENODEV;
        }

        misc_registered = 1;
        pr_info("initialized device: /dev/softsynth, node (MAJOR 10, MINOR %d)\n",
                synth_device.minor);
        pr_info("initialized device: /dev/softsynthu, node (MAJOR 10, MINOR %d)\n",
                synthu_device.minor);
        return 0;
}

static void softsynth_release(struct spk_synth *synth)
{
        misc_deregister(&synth_device);
        misc_deregister(&synthu_device);
        misc_registered = 0;
        pr_info("unregistered /dev/softsynth\n");
        pr_info("unregistered /dev/softsynthu\n");
}

static int softsynth_is_alive(struct spk_synth *synth)
{
        if (synth_soft.alive)
                return 1;
        return 0;
}

static int softsynth_adjust(struct spk_synth *synth, struct st_var_header *var)
{
        struct st_var_header *punc_level_var;
        struct var_t *var_data;

        if (var->var_id != PUNC_LEVEL)
                return 0;

        /* We want to set the the speech synthesis punctuation level
         * accordingly, so it properly tunes speaking A_PUNC characters */
        var_data = var->data;
        if (!var_data)
                return 0;
        punc_level_var = spk_get_var_header(PUNCT);
        if (!punc_level_var)
                return 0;
        spk_set_num_var(var_data->u.n.value, punc_level_var, E_SET);

        return 1;
}

module_param_named(start, synth_soft.startup, short, 0444);
module_param_named(direct, vars[DIRECT_ID].u.n.default_val, int, 0444);
module_param_named(rate, vars[RATE_ID].u.n.default_val, int, 0444);
module_param_named(pitch, vars[PITCH_ID].u.n.default_val, int, 0444);
module_param_named(inflection, vars[INFLECTION_ID].u.n.default_val, int, 0444);
module_param_named(vol, vars[VOL_ID].u.n.default_val, int, 0444);
module_param_named(tone, vars[TONE_ID].u.n.default_val, int, 0444);
module_param_named(punct, vars[PUNCT_ID].u.n.default_val, int, 0444);
module_param_named(voice, vars[VOICE_ID].u.n.default_val, int, 0444);
module_param_named(frequency, vars[FREQUENCY_ID].u.n.default_val, int, 0444);



MODULE_PARM_DESC(start, "Start the synthesizer once it is loaded.");
MODULE_PARM_DESC(direct, "Set the direct variable on load.");
MODULE_PARM_DESC(rate, "Sets the rate of the synthesizer.");
MODULE_PARM_DESC(pitch, "Sets the pitch of the synthesizer.");
MODULE_PARM_DESC(inflection, "Sets the inflection of the synthesizer.");
MODULE_PARM_DESC(vol, "Sets the volume of the speech synthesizer.");
MODULE_PARM_DESC(tone, "Sets the tone of the speech synthesizer.");
MODULE_PARM_DESC(punct, "Sets the amount of punctuation spoken by the synthesizer.");
MODULE_PARM_DESC(voice, "Sets the voice used by the synthesizer.");
MODULE_PARM_DESC(frequency, "Sets the frequency of speech synthesizer.");

module_spk_synth(synth_soft);

MODULE_AUTHOR("Kirk Reiser <kirk@braille.uwo.ca>");
MODULE_DESCRIPTION("Speakup userspace software synthesizer support");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);