// SPDX-License-Identifier: GPL-2.0
#include <linux/types.h>
#include <linux/ctype.h>        /* for isdigit() and friends */
#include <linux/fs.h>
#include <linux/mm.h>           /* for verify_area */
#include <linux/errno.h>        /* for -EBUSY */
#include <linux/ioport.h>       /* for check_region, request_region */
#include <linux/interrupt.h>
#include <linux/delay.h>        /* for loops_per_sec */
#include <linux/kmod.h>
#include <linux/jiffies.h>
#include <linux/uaccess.h>      /* for copy_from_user */
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/kthread.h>

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

static LIST_HEAD(synths);
struct spk_synth *synth;
char spk_pitch_buff[32] = "";
static int module_status;
bool spk_quiet_boot;

struct speakup_info_t speakup_info = {
        /*
         * This spinlock is used to protect the entire speakup machinery, and
         * must be taken at each kernel->speakup transition and released at
         * each corresponding speakup->kernel transition.
         *
         * The progression thread only interferes with the speakup machinery
         * through the synth buffer, so only needs to take the lock
         * while tinkering with the buffer.
         *
         * We use spin_lock/trylock_irqsave and spin_unlock_irqrestore with this
         * spinlock because speakup needs to disable the keyboard IRQ.
         */
        .spinlock = __SPIN_LOCK_UNLOCKED(speakup_info.spinlock),
        .flushing = 0,
};
EXPORT_SYMBOL_GPL(speakup_info);

static int do_synth_init(struct spk_synth *in_synth);

/*
 * Main loop of the progression thread: keep eating from the buffer
 * and push to the serial port, waiting as needed
 *
 * For devices that have a "full" notification mechanism, the driver can
 * adapt the loop the way they prefer.
 */
static void _spk_do_catch_up(struct spk_synth *synth, int unicode)
{
        u16 ch;
        unsigned long flags;
        unsigned long jiff_max;
        struct var_t *delay_time;
        struct var_t *full_time;
        struct var_t *jiffy_delta;
        int jiffy_delta_val;
        int delay_time_val;
        int full_time_val;
        int ret;

        jiffy_delta = spk_get_var(JIFFY);
        full_time = spk_get_var(FULL);
        delay_time = spk_get_var(DELAY);

        spin_lock_irqsave(&speakup_info.spinlock, flags);
        jiffy_delta_val = jiffy_delta->u.n.value;
        spin_unlock_irqrestore(&speakup_info.spinlock, flags);

        jiff_max = jiffies + jiffy_delta_val;
        while (!kthread_should_stop()) {
                spin_lock_irqsave(&speakup_info.spinlock, flags);
                if (speakup_info.flushing) {
                        speakup_info.flushing = 0;
                        spin_unlock_irqrestore(&speakup_info.spinlock, flags);
                        synth->flush(synth);
                        continue;
                }
                if (!unicode)
                        synth_buffer_skip_nonlatin1();
                if (synth_buffer_empty()) {
                        spin_unlock_irqrestore(&speakup_info.spinlock, flags);
                        break;
                }
                ch = synth_buffer_peek();
                set_current_state(TASK_INTERRUPTIBLE);
                full_time_val = full_time->u.n.value;
                spin_unlock_irqrestore(&speakup_info.spinlock, flags);
                if (ch == '\n')
                        ch = synth->procspeech;
                if (unicode)
                        ret = synth->io_ops->synth_out_unicode(synth, ch);
                else
                        ret = synth->io_ops->synth_out(synth, ch);
                if (!ret) {
                        schedule_timeout(msecs_to_jiffies(full_time_val));
                        continue;
                }
                if (time_after_eq(jiffies, jiff_max) && (ch == SPACE)) {
                        spin_lock_irqsave(&speakup_info.spinlock, flags);
                        jiffy_delta_val = jiffy_delta->u.n.value;
                        delay_time_val = delay_time->u.n.value;
                        full_time_val = full_time->u.n.value;
                        spin_unlock_irqrestore(&speakup_info.spinlock, flags);
                        if (synth->io_ops->synth_out(synth, synth->procspeech))
                                schedule_timeout(
                                        msecs_to_jiffies(delay_time_val));
                        else
                                schedule_timeout(
                                        msecs_to_jiffies(full_time_val));
                        jiff_max = jiffies + jiffy_delta_val;
                }
                set_current_state(TASK_RUNNING);
                spin_lock_irqsave(&speakup_info.spinlock, flags);
                synth_buffer_getc();
                spin_unlock_irqrestore(&speakup_info.spinlock, flags);
        }
        synth->io_ops->synth_out(synth, synth->procspeech);
}

void spk_do_catch_up(struct spk_synth *synth)
{
        _spk_do_catch_up(synth, 0);
}
EXPORT_SYMBOL_GPL(spk_do_catch_up);

void spk_do_catch_up_unicode(struct spk_synth *synth)
{
        _spk_do_catch_up(synth, 1);
}
EXPORT_SYMBOL_GPL(spk_do_catch_up_unicode);

void spk_synth_flush(struct spk_synth *synth)
{
        synth->io_ops->flush_buffer(synth);
        synth->io_ops->synth_out(synth, synth->clear);
}
EXPORT_SYMBOL_GPL(spk_synth_flush);

unsigned char spk_synth_get_index(struct spk_synth *synth)
{
        return synth->io_ops->synth_in_nowait(synth);
}
EXPORT_SYMBOL_GPL(spk_synth_get_index);

int spk_synth_is_alive_nop(struct spk_synth *synth)
{
        synth->alive = 1;
        return 1;
}
EXPORT_SYMBOL_GPL(spk_synth_is_alive_nop);

int spk_synth_is_alive_restart(struct spk_synth *synth)
{
        if (synth->alive)
                return 1;
        if (synth->io_ops->wait_for_xmitr(synth) > 0) {
                /* restart */
                synth->alive = 1;
                synth_printf("%s", synth->init);
                return 2; /* reenabled */
        }
        pr_warn("%s: can't restart synth\n", synth->long_name);
        return 0;
}
EXPORT_SYMBOL_GPL(spk_synth_is_alive_restart);

static void thread_wake_up(struct timer_list *unused)
{
        wake_up_interruptible_all(&speakup_event);
}

static DEFINE_TIMER(thread_timer, thread_wake_up);

void synth_start(void)
{
        struct var_t *trigger_time;

        if (!synth->alive) {
                synth_buffer_clear();
                return;
        }
        trigger_time = spk_get_var(TRIGGER);
        if (!timer_pending(&thread_timer))
                mod_timer(&thread_timer, jiffies +
                        msecs_to_jiffies(trigger_time->u.n.value));
}

void spk_do_flush(void)
{
        if (!synth)
                return;

        speakup_info.flushing = 1;
        synth_buffer_clear();
        if (synth->alive) {
                if (spk_pitch_shift) {
                        synth_printf("%s", spk_pitch_buff);
                        spk_pitch_shift = 0;
                }
        }
        wake_up_interruptible_all(&speakup_event);
        wake_up_process(speakup_task);
}

void synth_write(const char *_buf, size_t count)
{
        const unsigned char *buf = (const unsigned char *) _buf;

        while (count--)
                synth_buffer_add(*buf++);
        synth_start();
}

/* Consume one utf-8 character from buf (that contains up to count bytes),
 * returns the unicode codepoint if valid, -1 otherwise.
 * In all cases, returns the number of consumed bytes in *consumed,
 * and the minimum number of bytes that would be needed for the next character
 * in *want.
 */
s32 synth_utf8_get(const char *buf, size_t count, size_t *consumed, size_t *want)
{
        unsigned char c = buf[0];
        int nbytes = 8 - fls(c ^ 0xff);
        u32 value;
        size_t i;

        switch (nbytes) {
        case 8: /* 0xff */
        case 7: /* 0xfe */
        case 1: /* 0x80 */
                /* Invalid, drop */
                *consumed = 1;
                *want = 1;
                return -1;

        case 0:
                /* ASCII, take as such */
                *consumed = 1;
                *want = 1;
                return c;

        default:
                /* 2..6-byte UTF-8 */

                if (count < nbytes) {
                        /* We don't have it all */
                        *consumed = 0;
                        *want = nbytes;
                        return -1;
                }

                /* First byte */
                value = c & ((1u << (7 - nbytes)) - 1);

                /* Other bytes */
                for (i = 1; i < nbytes; i++) {
                        c = buf[i];
                        if ((c & 0xc0) != 0x80) {
                                /* Invalid, drop the head */
                                *consumed = i;
                                *want = 1;
                                return -1;
                        }
                        value = (value << 6) | (c & 0x3f);
                }

                *consumed = nbytes;
                *want = 1;
                return value;
        }
}

void synth_writeu(const char *buf, size_t count)
{
        size_t i, consumed, want;

        /* Convert to u16 */
        for (i = 0; i < count; i++) {
                s32 value;

                value = synth_utf8_get(buf + i, count - i, &consumed, &want);
                if (value == -1) {
                        /* Invalid or incomplete */

                        if (want > count - i)
                                /* We don't have it all, stop */
                                count = i;

                        continue;
                }

                if (value < 0x10000)
                        synth_buffer_add(value);
        }

        synth_start();
}

void synth_printf(const char *fmt, ...)
{
        va_list args;
        unsigned char buf[160];
        int r;

        va_start(args, fmt);
        r = vsnprintf(buf, sizeof(buf), fmt, args);
        va_end(args);
        if (r > sizeof(buf) - 1)
                r = sizeof(buf) - 1;

        synth_writeu(buf, r);
}
EXPORT_SYMBOL_GPL(synth_printf);

void synth_putwc(u16 wc)
{
        synth_buffer_add(wc);
}
EXPORT_SYMBOL_GPL(synth_putwc);

void synth_putwc_s(u16 wc)
{
        synth_buffer_add(wc);
        synth_start();
}
EXPORT_SYMBOL_GPL(synth_putwc_s);

void synth_putws(const u16 *buf)
{
        const u16 *p;

        for (p = buf; *p; p++)
                synth_buffer_add(*p);
}
EXPORT_SYMBOL_GPL(synth_putws);

void synth_putws_s(const u16 *buf)
{
        synth_putws(buf);
        synth_start();
}
EXPORT_SYMBOL_GPL(synth_putws_s);

static int index_count;
static int sentence_count;

void spk_reset_index_count(int sc)
{
        static int first = 1;

        if (first)
                first = 0;
        else
                synth->get_index(synth);
        index_count = 0;
        sentence_count = sc;
}

int synth_supports_indexing(void)
{
        if (synth->get_index)
                return 1;
        return 0;
}

void synth_insert_next_index(int sent_num)
{
        int out;

        if (synth->alive) {
                if (sent_num == 0) {
                        synth->indexing.currindex++;
                        index_count++;
                        if (synth->indexing.currindex >
                                        synth->indexing.highindex)
                                synth->indexing.currindex =
                                        synth->indexing.lowindex;
                }

                out = synth->indexing.currindex * 10 + sent_num;
                synth_printf(synth->indexing.command, out, out);
        }
}

void spk_get_index_count(int *linecount, int *sentcount)
{
        int ind = synth->get_index(synth);

        if (ind) {
                sentence_count = ind % 10;

                if ((ind / 10) <= synth->indexing.currindex)
                        index_count = synth->indexing.currindex - (ind / 10);
                else
                        index_count = synth->indexing.currindex
                                - synth->indexing.lowindex
                                + synth->indexing.highindex - (ind / 10) + 1;
        }
        *sentcount = sentence_count;
        *linecount = index_count;
}

static struct resource synth_res;

int synth_request_region(unsigned long start, unsigned long n)
{
        struct resource *parent = &ioport_resource;

        memset(&synth_res, 0, sizeof(synth_res));
        synth_res.name = synth->name;
        synth_res.start = start;
        synth_res.end = start + n - 1;
        synth_res.flags = IORESOURCE_BUSY;
        return request_resource(parent, &synth_res);
}
EXPORT_SYMBOL_GPL(synth_request_region);

int synth_release_region(unsigned long start, unsigned long n)
{
        return release_resource(&synth_res);
}
EXPORT_SYMBOL_GPL(synth_release_region);

struct var_t synth_time_vars[] = {
        { DELAY, .u.n = {NULL, 100, 100, 2000, 0, 0, NULL } },
        { TRIGGER, .u.n = {NULL, 20, 10, 2000, 0, 0, NULL } },
        { JIFFY, .u.n = {NULL, 50, 20, 200, 0, 0, NULL } },
        { FULL, .u.n = {NULL, 400, 200, 60000, 0, 0, NULL } },
        { FLUSH, .u.n = {NULL, 4000, 10, 4000, 0, 0, NULL } },
        V_LAST_VAR
};

/* called by: speakup_init() */
int synth_init(char *synth_name)
{
        int ret = 0;
        struct spk_synth *tmp, *synth = NULL;

        if (!synth_name)
                return 0;

        if (strcmp(synth_name, "none") == 0) {
                mutex_lock(&spk_mutex);
                synth_release();
                mutex_unlock(&spk_mutex);
                return 0;
        }

        mutex_lock(&spk_mutex);
        /* First, check if we already have it loaded. */
        list_for_each_entry(tmp, &synths, node) {
                if (strcmp(tmp->name, synth_name) == 0)
                        synth = tmp;
        }

        /* If we got one, initialize it now. */
        if (synth)
                ret = do_synth_init(synth);
        else
                ret = -ENODEV;
        mutex_unlock(&spk_mutex);

        return ret;
}

/* called by: synth_add() */
static int do_synth_init(struct spk_synth *in_synth)
{
        struct var_t *var;

        synth_release();
        if (in_synth->checkval != SYNTH_CHECK)
                return -EINVAL;
        synth = in_synth;
        synth->alive = 0;
        pr_warn("synth probe\n");
        if (synth->probe(synth) < 0) {
                pr_warn("%s: device probe failed\n", in_synth->name);
                synth = NULL;
                return -ENODEV;
        }
        synth_time_vars[0].u.n.value =
                synth_time_vars[0].u.n.default_val = synth->delay;
        synth_time_vars[1].u.n.value =
                synth_time_vars[1].u.n.default_val = synth->trigger;
        synth_time_vars[2].u.n.value =
                synth_time_vars[2].u.n.default_val = synth->jiffies;
        synth_time_vars[3].u.n.value =
                synth_time_vars[3].u.n.default_val = synth->full;
        synth_time_vars[4].u.n.value =
                synth_time_vars[4].u.n.default_val = synth->flush_time;
        synth_printf("%s", synth->init);
        for (var = synth->vars;
                (var->var_id >= 0) && (var->var_id < MAXVARS); var++)
                speakup_register_var(var);
        if (!spk_quiet_boot)
                synth_printf("%s found\n", synth->long_name);
        if (synth->attributes.name &&
            sysfs_create_group(speakup_kobj, &synth->attributes) < 0)
                return -ENOMEM;
        synth_flags = synth->flags;
        wake_up_interruptible_all(&speakup_event);
        if (speakup_task)
                wake_up_process(speakup_task);
        return 0;
}

void synth_release(void)
{
        struct var_t *var;
        unsigned long flags;

        if (!synth)
                return;
        spin_lock_irqsave(&speakup_info.spinlock, flags);
        pr_info("releasing synth %s\n", synth->name);
        synth->alive = 0;
        timer_delete(&thread_timer);
        spin_unlock_irqrestore(&speakup_info.spinlock, flags);
        if (synth->attributes.name)
                sysfs_remove_group(speakup_kobj, &synth->attributes);
        for (var = synth->vars; var->var_id != MAXVARS; var++)
                speakup_unregister_var(var->var_id);
        synth->release(synth);
        synth = NULL;
}

/* called by: all_driver_init() */
int synth_add(struct spk_synth *in_synth)
{
        int status = 0;
        struct spk_synth *tmp;

        mutex_lock(&spk_mutex);

        list_for_each_entry(tmp, &synths, node) {
                if (tmp == in_synth) {
                        mutex_unlock(&spk_mutex);
                        return 0;
                }
        }

        if (in_synth->startup)
                status = do_synth_init(in_synth);

        if (!status)
                list_add_tail(&in_synth->node, &synths);

        mutex_unlock(&spk_mutex);
        return status;
}
EXPORT_SYMBOL_GPL(synth_add);

void synth_remove(struct spk_synth *in_synth)
{
        mutex_lock(&spk_mutex);
        if (synth == in_synth)
                synth_release();
        list_del(&in_synth->node);
        module_status = 0;
        mutex_unlock(&spk_mutex);
}
EXPORT_SYMBOL_GPL(synth_remove);

struct spk_synth *synth_current(void)
{
        return synth;
}
EXPORT_SYMBOL_GPL(synth_current);

short spk_punc_masks[] = { 0, SOME, MOST, PUNC, PUNC | B_SYM };