serial_sicc.c

底层驱动开发

        siccuart_enable_tx_interrupt(info);
    spin_unlock_irqrestore(&info->state->sicc_lock,flags);
}


/*
 * This routine is used by the interrupt handler to schedule
 * processing in the software interrupt portion of the driver.
 */
static void siccuart_event(struct SICC_info *info, int event)
{
    info->event |= 1 << event;
    tasklet_schedule(&info->tlet);
}

static void
siccuart_rx_chars(struct SICC_info *info, struct pt_regs *regs)
{
    struct tty_struct *tty = info->tty;
    unsigned int status, ch, rsr, flg, ignored = 0;
    struct SICC_icount *icount = &info->state->icount;
    struct SICC_port *port = info->port;

    status = readb(port->uart_base+BL_SICC_LSR );
    while (status & _LSR_RBR_FULL) {
        ch = readb(port->uart_base+BL_SICC_RBR);

        if (tty->flip.count >= TTY_FLIPBUF_SIZE)
            goto ignore_char;
        icount->rx++;

        flg = TTY_NORMAL;

        /*
         * Note that the error handling code is
         * out of the main execution path
         */
        rsr = readb(port->uart_base+BL_SICC_LSR);
        if (rsr & _LSR_RX_ERR)
            goto handle_error;
#ifdef SUPPORT_SYSRQ
        if (info->sysrq) {
            if (ch && time_before(jiffies, info->sysrq)) {
                handle_sysrq(ch, regs, NULL);
                info->sysrq = 0;
                goto ignore_char;
            }
            info->sysrq = 0;
        }
#endif
    error_return:
        *tty->flip.flag_buf_ptr++ = flg;
        *tty->flip.char_buf_ptr++ = ch;
        tty->flip.count++;
    ignore_char:
        status = readb(port->uart_base+BL_SICC_LSR );
    }
out:
    tty_flip_buffer_push(tty);
    return;

handle_error:
    if (rsr & _LSR_LB_BREAK) {
        rsr &= ~(_LSR_FE_MASK | _LSR_PE_MASK);
        icount->brk++;

#ifdef SUPPORT_SYSRQ
        if (info->state->line == siccuart_cons.index) {
            if (!info->sysrq) {
                info->sysrq = jiffies + HZ*5;
                goto ignore_char;
            }
        }
#endif
    } else if (rsr & _LSR_PE_MASK)
        icount->parity++;
    else if (rsr & _LSR_FE_MASK)
        icount->frame++;
    if (rsr & _LSR_OE_MASK)
        icount->overrun++;

    if (rsr & info->ignore_status_mask) {
        if (++ignored > 100)
            goto out;
        goto ignore_char;
    }
    rsr &= info->read_status_mask;

    if (rsr & _LSR_LB_BREAK)
        flg = TTY_BREAK;
    else if (rsr &  _LSR_PE_MASK)
        flg = TTY_PARITY;
    else if (rsr &  _LSR_FE_MASK)
        flg = TTY_FRAME;

    if (rsr &  _LSR_OE_MASK) {
        /*
         * CHECK: does overrun affect the current character?
         * ASSUMPTION: it does not.
         */
        *tty->flip.flag_buf_ptr++ = flg;
        *tty->flip.char_buf_ptr++ = ch;
        tty->flip.count++;
        if (tty->flip.count >= TTY_FLIPBUF_SIZE)
            goto ignore_char;
        ch = 0;
        flg = TTY_OVERRUN;
    }
#ifdef SUPPORT_SYSRQ
    info->sysrq = 0;
#endif
    goto error_return;
}

static void siccuart_tx_chars(struct SICC_info *info)
{
    struct SICC_port *port = info->port;
    int count;
        unsigned char status;


    if (info->x_char) {
        writeb(info->x_char, port->uart_base+ BL_SICC_TBR);
        info->state->icount.tx++;
        info->x_char = 0;
        return;
    }
    if (info->xmit.head == info->xmit.tail
        || info->tty->stopped
        || info->tty->hw_stopped) {
        siccuart_disable_tx_interrupt(info);
                writeb(status&(~_LSR_RBR_MASK),port->uart_base+BL_SICC_LSR);
        return;
    }

    count = port->fifosize;
    do {
        writeb(info->xmit.buf[info->xmit.tail], port->uart_base+ BL_SICC_TBR);
        info->xmit.tail = (info->xmit.tail + 1) & (SICC_XMIT_SIZE - 1);
        info->state->icount.tx++;
        if (info->xmit.head == info->xmit.tail)
            break;
    } while (--count > 0);

    if (CIRC_CNT(info->xmit.head,
             info->xmit.tail,
             SICC_XMIT_SIZE) < WAKEUP_CHARS)
        siccuart_event(info, EVT_WRITE_WAKEUP);

    if (info->xmit.head == info->xmit.tail) {
        siccuart_disable_tx_interrupt(info);
    }
}


static irqreturn_t siccuart_int_rx(int irq, void *dev_id, struct pt_regs *regs)
{
    struct SICC_info *info = dev_id;
    siccuart_rx_chars(info, regs);
    return IRQ_HANDLED;
}


static irqreturn_t siccuart_int_tx(int irq, void *dev_id, struct pt_regs *regs)
{
    struct SICC_info *info = dev_id;
    siccuart_tx_chars(info);
    return IRQ_HANDLED;
}

static void siccuart_tasklet_action(unsigned long data)
{
    struct SICC_info *info = (struct SICC_info *)data;
    struct tty_struct *tty;

    tty = info->tty;
    if (!tty || !test_and_clear_bit(EVT_WRITE_WAKEUP, &info->event))
        return;

    if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) &&
        tty->ldisc.write_wakeup)
        (tty->ldisc.write_wakeup)(tty);
    wake_up_interruptible(&tty->write_wait);
}

static int siccuart_startup(struct SICC_info *info)
{
    unsigned long flags;
    unsigned long page;
    int retval = 0;

    if (info->flags & ASYNC_INITIALIZED) {
        return 0;
    }

    page = get_zeroed_page(GFP_KERNEL);
    if (!page)
        return -ENOMEM;

    if (info->port->uart_base == 0)
	info->port->uart_base = (int)ioremap(info->port->uart_base_phys, PAGE_SIZE);
    if (info->port->uart_base == 0) {
	free_page(page);
	return -ENOMEM;
    }

    /* lock access to info while doing setup */
    spin_lock_irqsave(&info->state->sicc_lock,flags);

    if (info->xmit.buf)
        free_page(page);
    else
        info->xmit.buf = (unsigned char *) page;


    info->mctrl = 0;
    if (info->tty->termios->c_cflag & CBAUD)
        info->mctrl = TIOCM_RTS | TIOCM_DTR;
    info->port->set_mctrl(info->port, info->mctrl);

    /*
     * initialise the old status of the modem signals
     */
    info->old_status = 0; // UART_GET_FR(info->port) & AMBA_UARTFR_MODEM_ANY;


    if (info->tty)
        clear_bit(TTY_IO_ERROR, &info->tty->flags);
    info->xmit.head = info->xmit.tail = 0;

    /*
     * Set up the tty->alt_speed kludge
     */
    if (info->tty) {
        if ((info->flags & ASYNC_SPD_MASK) == ASYNC_SPD_HI)
            info->tty->alt_speed = 57600;
        if ((info->flags & ASYNC_SPD_MASK) == ASYNC_SPD_VHI)
            info->tty->alt_speed = 115200;
        if ((info->flags & ASYNC_SPD_MASK) == ASYNC_SPD_SHI)
            info->tty->alt_speed = 230400;
        if ((info->flags & ASYNC_SPD_MASK) == ASYNC_SPD_WARP)
            info->tty->alt_speed = 460800;
    }


    writeb( 0x00, info->port->uart_base + BL_SICC_IrCR );  // disable IrDA


    /*
     * and set the speed of the serial port
     */
    siccuart_change_speed(info, 0);

    // enable rx/tx ports
    writeb(_RCR_ER_ENABLE /*| _RCR_PME_HARD*/, info->port->uart_base + BL_SICC_RCR);
    writeb(_TxCR_ET_ENABLE               , info->port->uart_base + BL_SICC_TxCR);

    readb(info->port->uart_base + BL_SICC_RBR); // clear rx port

    writeb(0xf8, info->port->uart_base + BL_SICC_LSR);   /* reset bits 0-4 of LSR */

    /*
     * Finally, enable interrupts
     */

     /*
     * Allocate the IRQ
     */
        retval = request_irq(info->port->irqrx, siccuart_int_rx, 0, "SICC rx", info);
        if (retval) {
             if (capable(CAP_SYS_ADMIN)) {
                   if (info->tty)
                          set_bit(TTY_IO_ERROR, &info->tty->flags);
                   retval = 0;
             }
              goto errout;
         }
    retval = request_irq(info->port->irqtx, siccuart_int_tx, 0, "SICC tx", info);
    if (retval) {
        if (capable(CAP_SYS_ADMIN)) {
            if (info->tty)
                set_bit(TTY_IO_ERROR, &info->tty->flags);
            retval = 0;
        }
        free_irq(info->port->irqrx, info);
        goto errout;
    }

    siccuart_enable_rx_interrupt(info);

    info->flags |= ASYNC_INITIALIZED;
    spin_unlock_irqrestore(&info->state->sicc_lock,flags);
    return 0;


errout:
    spin_unlock_irqrestore(&info->state->sicc_lock,flags);
    return retval;
}

/*
 * This routine will shutdown a serial port; interrupts are disabled, and
 * DTR is dropped if the hangup on close termio flag is on.
 */
static void siccuart_shutdown(struct SICC_info *info)
{
    unsigned long flags;

    if (!(info->flags & ASYNC_INITIALIZED))
        return;

    /* lock while shutting down port */
    spin_lock_irqsave(&info->state->sicc_lock,flags); /* Disable interrupts */

    /*
     * clear delta_msr_wait queue to avoid mem leaks: we may free the irq
     * here so the queue might never be woken up
     */
    wake_up_interruptible(&info->delta_msr_wait);

    /*
     * disable all interrupts, disable the port
     */
    siccuart_disable_rx_interrupt(info);
    siccuart_disable_tx_interrupt(info);

    /*
     * Free the IRQ
     */
    free_irq(info->port->irqtx, info);
    free_irq(info->port->irqrx, info);

    if (info->xmit.buf) {
        unsigned long pg = (unsigned long) info->xmit.buf;
        info->xmit.buf = NULL;
        free_page(pg);
    }


    if (!info->tty || (info->tty->termios->c_cflag & HUPCL))
        info->mctrl &= ~(TIOCM_DTR|TIOCM_RTS);
    info->port->set_mctrl(info->port, info->mctrl);

    /* kill off our tasklet */
    tasklet_kill(&info->tlet);
    if (info->tty)
        set_bit(TTY_IO_ERROR, &info->tty->flags);

    info->flags &= ~ASYNC_INITIALIZED;

    spin_unlock_irqrestore(&info->state->sicc_lock,flags);
}


static void siccuart_change_speed(struct SICC_info *info, struct termios *old_termios)
{
    unsigned int lcr_h, baud, quot, cflag, old_rcr, old_tcr, bits;
    unsigned long flags;

    if (!info->tty || !info->tty->termios)
        return;

    cflag = info->tty->termios->c_cflag;

    pr_debug("siccuart_set_cflag(0x%x) called\n", cflag);
    /* byte size and parity */
    switch (cflag & CSIZE) {
    case CS7: lcr_h =   _LCR_PE_DISABLE | _LCR_DB_7_BITS | _LCR_SB_1_BIT; bits = 9;  break;
    default:  lcr_h =   _LCR_PE_DISABLE | _LCR_DB_8_BITS | _LCR_SB_1_BIT; bits = 10; break; // CS8
    }
    if (cflag & CSTOPB) {
        lcr_h |= _LCR_SB_2_BIT;
        bits ++;
    }
    if (cflag & PARENB) {
        lcr_h |=  _LCR_PE_ENABLE;
        bits++;
        if (!(cflag & PARODD))
            lcr_h |=  _LCR_PTY_ODD;
        else
            lcr_h |=  _LCR_PTY_EVEN;
    }

    do {
        /* Determine divisor based on baud rate */
        baud = tty_get_baud_rate(info->tty);
        if (!baud)
            baud = 9600;


        {
           // here is ppc403SetBaud(com_port, baud);
           unsigned long divisor, clockSource, temp;

           /* Ensure CICCR[7] is 0 to select Internal Baud Clock */
           powerpcMtcic_cr((unsigned long)(powerpcMfcic_cr() & 0xFEFFFFFF));

           /* Determine Internal Baud Clock Frequency */
           /* powerpcMfclkgpcr() reads DCR 0x120 - the*/
           /* SCCR (Serial Clock Control Register) on Vesta */
           temp = powerpcMfclkgpcr();

           if(temp & 0x00000080) {