serialio.c

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#include <linux/interrupt.h>
#include <linux/ioport.h>

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

static void start_serial_interrupt(int irq);

static const struct old_serial_port rs_table[] = {
    SERIAL_PORT_DFNS
};
static const struct old_serial_port *serstate;
static int timeouts;

const struct old_serial_port *spk_serial_init(int index)
{
    int baud = 9600, quot = 0;
    unsigned int cval = 0;
    int cflag = CREAD | HUPCL | CLOCAL | B9600 | CS8;
    const struct old_serial_port *ser = rs_table + index;
    int err;

    /*  Divisor, bytesize and parity */
    quot = ser->baud_base / baud;
    cval = cflag & (CSIZE | CSTOPB);
#if defined(__powerpc__) || defined(__alpha__)
    cval >>= 8;
#else /* !__powerpc__ && !__alpha__ */
    cval >>= 4;
#endif /* !__powerpc__ && !__alpha__ */
    if (cflag & PARENB)
        cval |= UART_LCR_PARITY;
    if (!(cflag & PARODD))
        cval |= UART_LCR_EPAR;
    if (synth_request_region(ser->port, 8)) {
        /* try to take it back. */
        printk(KERN_INFO "Ports not available, trying to steal them\n");
        __release_region(&ioport_resource, ser->port, 8);
        err = synth_request_region(ser->port, 8);
        if (err) {
            pr_warn("Unable to allocate port at %x, errno %i",
                ser->port, err);
            return NULL;
        }
    }

    /*  Disable UART interrupts, set DTR and RTS high
     *  and set speed. */
    outb(cval | UART_LCR_DLAB, ser->port + UART_LCR);   /* set DLAB */
    outb(quot & 0xff, ser->port + UART_DLL);    /* LS of divisor */
    outb(quot >> 8, ser->port + UART_DLM);      /* MS of divisor */
    outb(cval, ser->port + UART_LCR);       /* reset DLAB */

    /* Turn off Interrupts */
    outb(0, ser->port + UART_IER);
    outb(UART_MCR_DTR | UART_MCR_RTS, ser->port + UART_MCR);

    /* If we read 0xff from the LSR, there is no UART here. */
    if (inb(ser->port + UART_LSR) == 0xff) {
        synth_release_region(ser->port, 8);
        serstate = NULL;
        return NULL;
    }

    mdelay(1);
    speakup_info.port_tts = ser->port;
    serstate = ser;

    start_serial_interrupt(ser->irq);

    return ser;
}

static irqreturn_t synth_readbuf_handler(int irq, void *dev_id)
{
    unsigned long flags;
/*printk(KERN_ERR "in irq\n"); */
/*pr_warn("in IRQ\n"); */
    int c;
    spk_lock(flags);
    while (inb_p(speakup_info.port_tts + UART_LSR) & UART_LSR_DR) {

        c = inb_p(speakup_info.port_tts+UART_RX);
        synth->read_buff_add((u_char) c);
/*printk(KERN_ERR "c = %d\n", c); */
/*pr_warn("C = %d\n", c); */
    }
    spk_unlock(flags);
    return IRQ_HANDLED;
}

static void start_serial_interrupt(int irq)
{
    int rv;

    if (synth->read_buff_add == NULL)
        return;

    rv = request_irq(irq, synth_readbuf_handler, IRQF_SHARED,
             "serial", (void *) synth_readbuf_handler);

    if (rv)
        printk(KERN_ERR "Unable to request Speakup serial I R Q\n");
    /* Set MCR */
    outb(UART_MCR_DTR | UART_MCR_RTS | UART_MCR_OUT2,
            speakup_info.port_tts + UART_MCR);
    /* Turn on Interrupts */
    outb(UART_IER_MSI|UART_IER_RLSI|UART_IER_RDI,
            speakup_info.port_tts + UART_IER);
    inb(speakup_info.port_tts+UART_LSR);
    inb(speakup_info.port_tts+UART_RX);
    inb(speakup_info.port_tts+UART_IIR);
    inb(speakup_info.port_tts+UART_MSR);
    outb(1, speakup_info.port_tts + UART_FCR);  /* Turn FIFO On */
}

void stop_serial_interrupt(void)
{
    if (speakup_info.port_tts == 0)
        return;

    if (synth->read_buff_add == NULL)
        return;

    /* Turn off interrupts */
    outb(0, speakup_info.port_tts+UART_IER);
    /* Free IRQ */
    free_irq(serstate->irq, (void *) synth_readbuf_handler);
}

int wait_for_xmitr(void)
{
    int tmout = SPK_XMITR_TIMEOUT;
    if ((synth->alive) && (timeouts >= NUM_DISABLE_TIMEOUTS)) {
        pr_warn("%s: too many timeouts, deactivating speakup\n",
            synth->long_name);
        synth->alive = 0;
        /* No synth any more, so nobody will restart TTYs, and we thus
         * need to do it ourselves.  Now that there is no synth we can
         * let application flood anyway */
        speakup_start_ttys();
        timeouts = 0;
        return 0;
    }
    while (spk_serial_tx_busy()) {
        if (--tmout == 0) {
            pr_warn("%s: timed out (tx busy)\n", synth->long_name);
            timeouts++;
            return 0;
        }
        udelay(1);
    }
    tmout = SPK_CTS_TIMEOUT;
    while (!((inb_p(speakup_info.port_tts + UART_MSR)) & UART_MSR_CTS)) {
        /* CTS */
        if (--tmout == 0) {
            /* pr_warn("%s: timed out (cts)\n",
             * synth->long_name); */
            timeouts++;
            return 0;
        }
        udelay(1);
    }
    timeouts = 0;
    return 1;
}

unsigned char spk_serial_in(void)
{
    int tmout = SPK_SERIAL_TIMEOUT;

    while (!(inb_p(speakup_info.port_tts + UART_LSR) & UART_LSR_DR)) {
        if (--tmout == 0) {
            pr_warn("time out while waiting for input.\n");
            return 0xff;
        }
        udelay(1);
    }
    return inb_p(speakup_info.port_tts + UART_RX);
}
EXPORT_SYMBOL_GPL(spk_serial_in);

unsigned char spk_serial_in_nowait(void)
{
    unsigned char lsr;

    lsr = inb_p(speakup_info.port_tts + UART_LSR);
    if (!(lsr & UART_LSR_DR))
        return 0;
    return inb_p(speakup_info.port_tts + UART_RX);
}
EXPORT_SYMBOL_GPL(spk_serial_in_nowait);

int spk_serial_out(const char ch)
{
    if (synth->alive && wait_for_xmitr()) {
        outb_p(ch, speakup_info.port_tts);
        return 1;
    }
    return 0;
}
EXPORT_SYMBOL_GPL(spk_serial_out);

void spk_serial_release(void)
{
    if (speakup_info.port_tts == 0)
        return;
    synth_release_region(speakup_info.port_tts, 8);
    speakup_info.port_tts = 0;
}
EXPORT_SYMBOL_GPL(spk_serial_release);