/*
 *  Driver for CPM (SCC/SMC) serial ports; core driver
 *
 *  Based on arch/ppc/cpm2_io/uart.c by Dan Malek
 *  Based on ppc8xx.c by Thomas Gleixner
 *  Based on drivers/serial/amba.c by Russell King
 *
 *  Maintainer: Kumar Gala (galak@kernel.crashing.org) (CPM2)
 *              Pantelis Antoniou (panto@intracom.gr) (CPM1)
 *
 *  Copyright (C) 2004, 2007 Freescale Semiconductor, Inc.
 *            (C) 2004 Intracom, S.A.
 *            (C) 2005-2006 MontaVista Software, Inc.
 *              Vitaly Bordug <vbordug@ru.mvista.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#include <linux/module.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/serial.h>
#include <linux/console.h>
#include <linux/sysrq.h>
#include <linux/device.h>
#include <linux/bootmem.h>
#include <linux/dma-mapping.h>
#include <linux/fs_uart_pd.h>
#include <linux/of_platform.h>
#include <linux/gpio.h>
#include <linux/of_gpio.h>
#include <linux/clk.h>

#include <asm/io.h>
#include <asm/irq.h>
#include <asm/delay.h>
#include <asm/fs_pd.h>
#include <asm/udbg.h>

#if defined(CONFIG_SERIAL_CPM_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif

#include <linux/serial_core.h>
#include <linux/kernel.h>

#include "cpm_uart.h"


/**************************************************************/

static int  cpm_uart_tx_pump(struct uart_port *port);
static void cpm_uart_init_smc(struct uart_cpm_port *pinfo);
static void cpm_uart_init_scc(struct uart_cpm_port *pinfo);
static void cpm_uart_initbd(struct uart_cpm_port *pinfo);

/**************************************************************/

#define HW_BUF_SPD_THRESHOLD    2400

/*
 * Check, if transmit buffers are processed
*/
static unsigned int cpm_uart_tx_empty(struct uart_port *port)
{
        struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;
        cbd_t __iomem *bdp = pinfo->tx_bd_base;
        int ret = 0;

        while (1) {
                if (in_be16(&bdp->cbd_sc) & BD_SC_READY)
                        break;

                if (in_be16(&bdp->cbd_sc) & BD_SC_WRAP) {
                        ret = TIOCSER_TEMT;
                        break;
                }
                bdp++;
        }

        pr_debug("CPM uart[%d]:tx_empty: %d\n", port->line, ret);

        return ret;
}

static void cpm_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
        struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;

        if (pinfo->gpios[GPIO_RTS] >= 0)
                gpio_set_value(pinfo->gpios[GPIO_RTS], !(mctrl & TIOCM_RTS));

        if (pinfo->gpios[GPIO_DTR] >= 0)
                gpio_set_value(pinfo->gpios[GPIO_DTR], !(mctrl & TIOCM_DTR));
}

static unsigned int cpm_uart_get_mctrl(struct uart_port *port)
{
        struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;
        unsigned int mctrl = TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;

        if (pinfo->gpios[GPIO_CTS] >= 0) {
                if (gpio_get_value(pinfo->gpios[GPIO_CTS]))
                        mctrl &= ~TIOCM_CTS;
        }

        if (pinfo->gpios[GPIO_DSR] >= 0) {
                if (gpio_get_value(pinfo->gpios[GPIO_DSR]))
                        mctrl &= ~TIOCM_DSR;
        }

        if (pinfo->gpios[GPIO_DCD] >= 0) {
                if (gpio_get_value(pinfo->gpios[GPIO_DCD]))
                        mctrl &= ~TIOCM_CAR;
        }

        if (pinfo->gpios[GPIO_RI] >= 0) {
                if (!gpio_get_value(pinfo->gpios[GPIO_RI]))
                        mctrl |= TIOCM_RNG;
        }

        return mctrl;
}

/*
 * Stop transmitter
 */
static void cpm_uart_stop_tx(struct uart_port *port)
{
        struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;
        smc_t __iomem *smcp = pinfo->smcp;
        scc_t __iomem *sccp = pinfo->sccp;

        pr_debug("CPM uart[%d]:stop tx\n", port->line);

        if (IS_SMC(pinfo))
                clrbits8(&smcp->smc_smcm, SMCM_TX);
        else
                clrbits16(&sccp->scc_sccm, UART_SCCM_TX);
}

/*
 * Start transmitter
 */
static void cpm_uart_start_tx(struct uart_port *port)
{
        struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;
        smc_t __iomem *smcp = pinfo->smcp;
        scc_t __iomem *sccp = pinfo->sccp;

        pr_debug("CPM uart[%d]:start tx\n", port->line);

        if (IS_SMC(pinfo)) {
                if (in_8(&smcp->smc_smcm) & SMCM_TX)
                        return;
        } else {
                if (in_be16(&sccp->scc_sccm) & UART_SCCM_TX)
                        return;
        }

        if (cpm_uart_tx_pump(port) != 0) {
                if (IS_SMC(pinfo)) {
                        setbits8(&smcp->smc_smcm, SMCM_TX);
                } else {
                        setbits16(&sccp->scc_sccm, UART_SCCM_TX);
                }
        }
}

/*
 * Stop receiver
 */
static void cpm_uart_stop_rx(struct uart_port *port)
{
        struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;
        smc_t __iomem *smcp = pinfo->smcp;
        scc_t __iomem *sccp = pinfo->sccp;

        pr_debug("CPM uart[%d]:stop rx\n", port->line);

        if (IS_SMC(pinfo))
                clrbits8(&smcp->smc_smcm, SMCM_RX);
        else
                clrbits16(&sccp->scc_sccm, UART_SCCM_RX);
}

/*
 * Enable Modem status interrupts
 */
static void cpm_uart_enable_ms(struct uart_port *port)
{
        pr_debug("CPM uart[%d]:enable ms\n", port->line);
}

/*
 * Generate a break.
 */
static void cpm_uart_break_ctl(struct uart_port *port, int break_state)
{
        struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;

        pr_debug("CPM uart[%d]:break ctrl, break_state: %d\n", port->line,
                break_state);

        if (break_state)
                cpm_line_cr_cmd(pinfo, CPM_CR_STOP_TX);
        else
                cpm_line_cr_cmd(pinfo, CPM_CR_RESTART_TX);
}

/*
 * Transmit characters, refill buffer descriptor, if possible
 */
static void cpm_uart_int_tx(struct uart_port *port)
{
        pr_debug("CPM uart[%d]:TX INT\n", port->line);

        cpm_uart_tx_pump(port);
}

#ifdef CONFIG_CONSOLE_POLL
static int serial_polled;
#endif

/*
 * Receive characters
 */
static void cpm_uart_int_rx(struct uart_port *port)
{
        int i;
        unsigned char ch;
        u8 *cp;
        struct tty_port *tport = &port->state->port;
        struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;
        cbd_t __iomem *bdp;
        u16 status;
        unsigned int flg;

        pr_debug("CPM uart[%d]:RX INT\n", port->line);

        /* Just loop through the closed BDs and copy the characters into
         * the buffer.
         */
        bdp = pinfo->rx_cur;
        for (;;) {
#ifdef CONFIG_CONSOLE_POLL
                if (unlikely(serial_polled)) {
                        serial_polled = 0;
                        return;
                }
#endif
                /* get status */
                status = in_be16(&bdp->cbd_sc);
                /* If this one is empty, return happy */
                if (status & BD_SC_EMPTY)
                        break;

                /* get number of characters, and check spce in flip-buffer */
                i = in_be16(&bdp->cbd_datlen);

                /* If we have not enough room in tty flip buffer, then we try
                 * later, which will be the next rx-interrupt or a timeout
                 */
                if (tty_buffer_request_room(tport, i) < i) {
                        printk(KERN_WARNING "No room in flip buffer\n");
                        return;
                }

                /* get pointer */
                cp = cpm2cpu_addr(in_be32(&bdp->cbd_bufaddr), pinfo);

                /* loop through the buffer */
                while (i-- > 0) {
                        ch = *cp++;
                        port->icount.rx++;
                        flg = TTY_NORMAL;

                        if (status &
                            (BD_SC_BR | BD_SC_FR | BD_SC_PR | BD_SC_OV))
                                goto handle_error;
                        if (uart_handle_sysrq_char(port, ch))
                                continue;
#ifdef CONFIG_CONSOLE_POLL
                        if (unlikely(serial_polled)) {
                                serial_polled = 0;
                                return;
                        }
#endif
                      error_return:
                        tty_insert_flip_char(tport, ch, flg);

                }               /* End while (i--) */

                /* This BD is ready to be used again. Clear status. get next */
                clrbits16(&bdp->cbd_sc, BD_SC_BR | BD_SC_FR | BD_SC_PR |
                                        BD_SC_OV | BD_SC_ID);
                setbits16(&bdp->cbd_sc, BD_SC_EMPTY);

                if (in_be16(&bdp->cbd_sc) & BD_SC_WRAP)
                        bdp = pinfo->rx_bd_base;
                else
                        bdp++;

        } /* End for (;;) */

        /* Write back buffer pointer */
        pinfo->rx_cur = bdp;

        /* activate BH processing */
        tty_flip_buffer_push(tport);

        return;

        /* Error processing */

      handle_error:
        /* Statistics */
        if (status & BD_SC_BR)
                port->icount.brk++;
        if (status & BD_SC_PR)
                port->icount.parity++;
        if (status & BD_SC_FR)
                port->icount.frame++;
        if (status & BD_SC_OV)
                port->icount.overrun++;

        /* Mask out ignored conditions */
        status &= port->read_status_mask;

        /* Handle the remaining ones */
        if (status & BD_SC_BR)
                flg = TTY_BREAK;
        else if (status & BD_SC_PR)
                flg = TTY_PARITY;
        else if (status & BD_SC_FR)
                flg = TTY_FRAME;

        /* overrun does not affect the current character ! */
        if (status & BD_SC_OV) {
                ch = 0;
                flg = TTY_OVERRUN;
                /* We skip this buffer */
                /* CHECK: Is really nothing senseful there */
                /* ASSUMPTION: it contains nothing valid */
                i = 0;
        }
#ifdef SUPPORT_SYSRQ
        port->sysrq = 0;
#endif
        goto error_return;
}

/*
 * Asynchron mode interrupt handler
 */
static irqreturn_t cpm_uart_int(int irq, void *data)
{
        u8 events;
        struct uart_port *port = data;
        struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;
        smc_t __iomem *smcp = pinfo->smcp;
        scc_t __iomem *sccp = pinfo->sccp;

        pr_debug("CPM uart[%d]:IRQ\n", port->line);

        if (IS_SMC(pinfo)) {
                events = in_8(&smcp->smc_smce);
                out_8(&smcp->smc_smce, events);
                if (events & SMCM_BRKE)
                        uart_handle_break(port);
                if (events & SMCM_RX)
                        cpm_uart_int_rx(port);
                if (events & SMCM_TX)
                        cpm_uart_int_tx(port);
        } else {
                events = in_be16(&sccp->scc_scce);
                out_be16(&sccp->scc_scce, events);
                if (events & UART_SCCM_BRKE)
                        uart_handle_break(port);
                if (events & UART_SCCM_RX)
                        cpm_uart_int_rx(port);
                if (events & UART_SCCM_TX)
                        cpm_uart_int_tx(port);
        }
        return (events) ? IRQ_HANDLED : IRQ_NONE;
}

static int cpm_uart_startup(struct uart_port *port)
{
        int retval;
        struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;

        pr_debug("CPM uart[%d]:startup\n", port->line);

        /* If the port is not the console, make sure rx is disabled. */
        if (!(pinfo->flags & FLAG_CONSOLE)) {
                /* Disable UART rx */
                if (IS_SMC(pinfo)) {
                        clrbits16(&pinfo->smcp->smc_smcmr, SMCMR_REN);
                        clrbits8(&pinfo->smcp->smc_smcm, SMCM_RX);
                } else {
                        clrbits32(&pinfo->sccp->scc_gsmrl, SCC_GSMRL_ENR);
                        clrbits16(&pinfo->sccp->scc_sccm, UART_SCCM_RX);
                }
                cpm_uart_initbd(pinfo);
                cpm_line_cr_cmd(pinfo, CPM_CR_INIT_TRX);
        }
        /* Install interrupt handler. */
        retval = request_irq(port->irq, cpm_uart_int, 0, "cpm_uart", port);
        if (retval)
                return retval;

        /* Startup rx-int */
        if (IS_SMC(pinfo)) {
                setbits8(&pinfo->smcp->smc_smcm, SMCM_RX);
                setbits16(&pinfo->smcp->smc_smcmr, (SMCMR_REN | SMCMR_TEN));
        } else {
                setbits16(&pinfo->sccp->scc_sccm, UART_SCCM_RX);
                setbits32(&pinfo->sccp->scc_gsmrl, (SCC_GSMRL_ENR | SCC_GSMRL_ENT));
        }

        return 0;
}

inline void cpm_uart_wait_until_send(struct uart_cpm_port *pinfo)
{
        set_current_state(TASK_UNINTERRUPTIBLE);
        schedule_timeout(pinfo->wait_closing);
}

/*
 * Shutdown the uart
 */
static void cpm_uart_shutdown(struct uart_port *port)
{
        struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;

        pr_debug("CPM uart[%d]:shutdown\n", port->line);

        /* free interrupt handler */
        free_irq(port->irq, port);

        /* If the port is not the console, disable Rx and Tx. */
        if (!(pinfo->flags & FLAG_CONSOLE)) {
                /* Wait for all the BDs marked sent */
                while(!cpm_uart_tx_empty(port)) {
                        set_current_state(TASK_UNINTERRUPTIBLE);
                        schedule_timeout(2);
                }

                if (pinfo->wait_closing)
                        cpm_uart_wait_until_send(pinfo);

                /* Stop uarts */
                if (IS_SMC(pinfo)) {
                        smc_t __iomem *smcp = pinfo->smcp;
                        clrbits16(&smcp->smc_smcmr, SMCMR_REN | SMCMR_TEN);
                        clrbits8(&smcp->smc_smcm, SMCM_RX | SMCM_TX);
                } else {
                        scc_t __iomem *sccp = pinfo->sccp;
                        clrbits32(&sccp->scc_gsmrl, SCC_GSMRL_ENR | SCC_GSMRL_ENT);
                        clrbits16(&sccp->scc_sccm, UART_SCCM_TX | UART_SCCM_RX);
                }

                /* Shut them really down and reinit buffer descriptors */
                if (IS_SMC(pinfo)) {
                        out_be16(&pinfo->smcup->smc_brkcr, 0);
                        cpm_line_cr_cmd(pinfo, CPM_CR_STOP_TX);
                } else {
                        out_be16(&pinfo->sccup->scc_brkcr, 0);
                        cpm_line_cr_cmd(pinfo, CPM_CR_GRA_STOP_TX);
                }

                cpm_uart_initbd(pinfo);
        }
}

static void cpm_uart_set_termios(struct uart_port *port,
                                 struct ktermios *termios,
                                 struct ktermios *old)
{
        int baud;
        unsigned long flags;
        u16 cval, scval, prev_mode;
        int bits, sbits;
        struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;
        smc_t __iomem *smcp = pinfo->smcp;
        scc_t __iomem *sccp = pinfo->sccp;
        int maxidl;

        pr_debug("CPM uart[%d]:set_termios\n", port->line);

        baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16);
        if (baud < HW_BUF_SPD_THRESHOLD ||
            (pinfo->port.state && pinfo->port.state->port.low_latency))
                pinfo->rx_fifosize = 1;
        else
                pinfo->rx_fifosize = RX_BUF_SIZE;

        /* MAXIDL is the timeout after which a receive buffer is closed
         * when not full if no more characters are received.
         * We calculate it from the baudrate so that the duration is
         * always the same at standard rates: about 4ms.
         */
        maxidl = baud / 2400;
        if (maxidl < 1)
                maxidl = 1;
        if (maxidl > 0x10)
                maxidl = 0x10;

        /* Character length programmed into the mode register is the
         * sum of: 1 start bit, number of data bits, 0 or 1 parity bit,
         * 1 or 2 stop bits, minus 1.
         * The value 'bits' counts this for us.
         */
        cval = 0;
        scval = 0;

        /* byte size */
        switch (termios->c_cflag & CSIZE) {
        case CS5:
                bits = 5;
                break;
        case CS6:
                bits = 6;
                break;
        case CS7:
                bits = 7;
                break;
        case CS8:
                bits = 8;
                break;
                /* Never happens, but GCC is too dumb to figure it out */
        default:
                bits = 8;
                break;
        }
        sbits = bits - 5;

        if (termios->c_cflag & CSTOPB) {
                cval |= SMCMR_SL;       /* Two stops */
                scval |= SCU_PSMR_SL;
                bits++;
        }

        if (termios->c_cflag & PARENB) {
                cval |= SMCMR_PEN;
                scval |= SCU_PSMR_PEN;
                bits++;
                if (!(termios->c_cflag & PARODD)) {
                        cval |= SMCMR_PM_EVEN;
                        scval |= (SCU_PSMR_REVP | SCU_PSMR_TEVP);
                }
        }

        /*
         * Update the timeout
         */
        uart_update_timeout(port, termios->c_cflag, baud);

        /*
         * Set up parity check flag
         */
#define RELEVANT_IFLAG(iflag) (iflag & (IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK))

        port->read_status_mask = (BD_SC_EMPTY | BD_SC_OV);
        if (termios->c_iflag & INPCK)
                port->read_status_mask |= BD_SC_FR | BD_SC_PR;
        if ((termios->c_iflag & BRKINT) || (termios->c_iflag & PARMRK))
                port->read_status_mask |= BD_SC_BR;

        /*
         * Characters to ignore
         */
        port->ignore_status_mask = 0;
        if (termios->c_iflag & IGNPAR)
                port->ignore_status_mask |= BD_SC_PR | BD_SC_FR;
        if (termios->c_iflag & IGNBRK) {
                port->ignore_status_mask |= BD_SC_BR;
                /*
                 * If we're ignore parity and break indicators, ignore
                 * overruns too.  (For real raw support).
                 */
                if (termios->c_iflag & IGNPAR)
                        port->ignore_status_mask |= BD_SC_OV;
        }
        /*
         * !!! ignore all characters if CREAD is not set
         */
        if ((termios->c_cflag & CREAD) == 0)
                port->read_status_mask &= ~BD_SC_EMPTY;

        spin_lock_irqsave(&port->lock, flags);

        /* Start bit has not been added (so don't, because we would just
         * subtract it later), and we need to add one for the number of
         * stops bits (there is always at least one).
         */
        bits++;
        if (IS_SMC(pinfo)) {
                /*
                 * MRBLR can be changed while an SMC/SCC is operating only
                 * if it is done in a single bus cycle with one 16-bit move
                 * (not two 8-bit bus cycles back-to-back). This occurs when
                 * the cp shifts control to the next RxBD, so the change does
                 * not take effect immediately. To guarantee the exact RxBD
                 * on which the change occurs, change MRBLR only while the
                 * SMC/SCC receiver is disabled.
                 */
                out_be16(&pinfo->smcup->smc_mrblr, pinfo->rx_fifosize);
                out_be16(&pinfo->smcup->smc_maxidl, maxidl);

                /* Set the mode register.  We want to keep a copy of the
                 * enables, because we want to put them back if they were
                 * present.
                 */
                prev_mode = in_be16(&smcp->smc_smcmr) & (SMCMR_REN | SMCMR_TEN);
                /* Output in *one* operation, so we don't interrupt RX/TX if they
                 * were already enabled. */
                out_be16(&smcp->smc_smcmr, smcr_mk_clen(bits) | cval |
                    SMCMR_SM_UART | prev_mode);
        } else {
                out_be16(&pinfo->sccup->scc_genscc.scc_mrblr, pinfo->rx_fifosize);
                out_be16(&pinfo->sccup->scc_maxidl, maxidl);
                out_be16(&sccp->scc_psmr, (sbits << 12) | scval);
        }

        if (pinfo->clk)
                clk_set_rate(pinfo->clk, baud);
        else
                cpm_set_brg(pinfo->brg - 1, baud);
        spin_unlock_irqrestore(&port->lock, flags);
}

static const char *cpm_uart_type(struct uart_port *port)
{
        pr_debug("CPM uart[%d]:uart_type\n", port->line);

        return port->type == PORT_CPM ? "CPM UART" : NULL;
}

/*
 * verify the new serial_struct (for TIOCSSERIAL).
 */
static int cpm_uart_verify_port(struct uart_port *port,
                                struct serial_struct *ser)
{
        int ret = 0;

        pr_debug("CPM uart[%d]:verify_port\n", port->line);

        if (ser->type != PORT_UNKNOWN && ser->type != PORT_CPM)
                ret = -EINVAL;
        if (ser->irq < 0 || ser->irq >= nr_irqs)
                ret = -EINVAL;
        if (ser->baud_base < 9600)
                ret = -EINVAL;
        return ret;
}

/*
 * Transmit characters, refill buffer descriptor, if possible
 */
static int cpm_uart_tx_pump(struct uart_port *port)
{
        cbd_t __iomem *bdp;
        u8 *p;
        int count;
        struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;
        struct circ_buf *xmit = &port->state->xmit;

        /* Handle xon/xoff */
        if (port->x_char) {
                /* Pick next descriptor and fill from buffer */
                bdp = pinfo->tx_cur;

                p = cpm2cpu_addr(in_be32(&bdp->cbd_bufaddr), pinfo);

                *p++ = port->x_char;

                out_be16(&bdp->cbd_datlen, 1);
                setbits16(&bdp->cbd_sc, BD_SC_READY);
                /* Get next BD. */
                if (in_be16(&bdp->cbd_sc) & BD_SC_WRAP)
                        bdp = pinfo->tx_bd_base;
                else
                        bdp++;
                pinfo->tx_cur = bdp;

                port->icount.tx++;
                port->x_char = 0;
                return 1;
        }

        if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
                cpm_uart_stop_tx(port);
                return 0;
        }

        /* Pick next descriptor and fill from buffer */
        bdp = pinfo->tx_cur;

        while (!(in_be16(&bdp->cbd_sc) & BD_SC_READY) &&
               xmit->tail != xmit->head) {
                count = 0;
                p = cpm2cpu_addr(in_be32(&bdp->cbd_bufaddr), pinfo);
                while (count < pinfo->tx_fifosize) {
                        *p++ = xmit->buf[xmit->tail];
                        xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
                        port->icount.tx++;
                        count++;
                        if (xmit->head == xmit->tail)
                                break;
                }
                out_be16(&bdp->cbd_datlen, count);
                setbits16(&bdp->cbd_sc, BD_SC_READY);
                /* Get next BD. */
                if (in_be16(&bdp->cbd_sc) & BD_SC_WRAP)
                        bdp = pinfo->tx_bd_base;
                else
                        bdp++;
        }
        pinfo->tx_cur = bdp;

        if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
                uart_write_wakeup(port);

        if (uart_circ_empty(xmit)) {
                cpm_uart_stop_tx(port);
                return 0;
        }

        return 1;
}

/*
 * init buffer descriptors
 */
static void cpm_uart_initbd(struct uart_cpm_port *pinfo)
{
        int i;
        u8 *mem_addr;
        cbd_t __iomem *bdp;

        pr_debug("CPM uart[%d]:initbd\n", pinfo->port.line);

        /* Set the physical address of the host memory
         * buffers in the buffer descriptors, and the
         * virtual address for us to work with.
         */
        mem_addr = pinfo->mem_addr;
        bdp = pinfo->rx_cur = pinfo->rx_bd_base;
        for (i = 0; i < (pinfo->rx_nrfifos - 1); i++, bdp++) {
                out_be32(&bdp->cbd_bufaddr, cpu2cpm_addr(mem_addr, pinfo));
                out_be16(&bdp->cbd_sc, BD_SC_EMPTY | BD_SC_INTRPT);
                mem_addr += pinfo->rx_fifosize;
        }

        out_be32(&bdp->cbd_bufaddr, cpu2cpm_addr(mem_addr, pinfo));
        out_be16(&bdp->cbd_sc, BD_SC_WRAP | BD_SC_EMPTY | BD_SC_INTRPT);

        /* Set the physical address of the host memory
         * buffers in the buffer descriptors, and the
         * virtual address for us to work with.
         */
        mem_addr = pinfo->mem_addr + L1_CACHE_ALIGN(pinfo->rx_nrfifos * pinfo->rx_fifosize);
        bdp = pinfo->tx_cur = pinfo->tx_bd_base;
        for (i = 0; i < (pinfo->tx_nrfifos - 1); i++, bdp++) {
                out_be32(&bdp->cbd_bufaddr, cpu2cpm_addr(mem_addr, pinfo));
                out_be16(&bdp->cbd_sc, BD_SC_INTRPT);
                mem_addr += pinfo->tx_fifosize;
        }

        out_be32(&bdp->cbd_bufaddr, cpu2cpm_addr(mem_addr, pinfo));
        out_be16(&bdp->cbd_sc, BD_SC_WRAP | BD_SC_INTRPT);
}

static void cpm_uart_init_scc(struct uart_cpm_port *pinfo)
{
        scc_t __iomem *scp;
        scc_uart_t __iomem *sup;

        pr_debug("CPM uart[%d]:init_scc\n", pinfo->port.line);

        scp = pinfo->sccp;
        sup = pinfo->sccup;

        /* Store address */
        out_be16(&pinfo->sccup->scc_genscc.scc_rbase,
                 (u8 __iomem *)pinfo->rx_bd_base - DPRAM_BASE);
        out_be16(&pinfo->sccup->scc_genscc.scc_tbase,
                 (u8 __iomem *)pinfo->tx_bd_base - DPRAM_BASE);

        /* Set up the uart parameters in the
         * parameter ram.
         */

        cpm_set_scc_fcr(sup);

        out_be16(&sup->scc_genscc.scc_mrblr, pinfo->rx_fifosize);
        out_be16(&sup->scc_maxidl, 0x10);
        out_be16(&sup->scc_brkcr, 1);
        out_be16(&sup->scc_parec, 0);
        out_be16(&sup->scc_frmec, 0);
        out_be16(&sup->scc_nosec, 0);
        out_be16(&sup->scc_brkec, 0);
        out_be16(&sup->scc_uaddr1, 0);
        out_be16(&sup->scc_uaddr2, 0);
        out_be16(&sup->scc_toseq, 0);
        out_be16(&sup->scc_char1, 0x8000);
        out_be16(&sup->scc_char2, 0x8000);
        out_be16(&sup->scc_char3, 0x8000);
        out_be16(&sup->scc_char4, 0x8000);
        out_be16(&sup->scc_char5, 0x8000);
        out_be16(&sup->scc_char6, 0x8000);
        out_be16(&sup->scc_char7, 0x8000);
        out_be16(&sup->scc_char8, 0x8000);
        out_be16(&sup->scc_rccm, 0xc0ff);

        /* Send the CPM an initialize command.
         */
        cpm_line_cr_cmd(pinfo, CPM_CR_INIT_TRX);

        /* Set UART mode, 8 bit, no parity, one stop.
         * Enable receive and transmit.
         */
        out_be32(&scp->scc_gsmrh, 0);
        out_be32(&scp->scc_gsmrl,
                 SCC_GSMRL_MODE_UART | SCC_GSMRL_TDCR_16 | SCC_GSMRL_RDCR_16);

        /* Enable rx interrupts  and clear all pending events.  */
        out_be16(&scp->scc_sccm, 0);
        out_be16(&scp->scc_scce, 0xffff);
        out_be16(&scp->scc_dsr, 0x7e7e);
        out_be16(&scp->scc_psmr, 0x3000);

        setbits32(&scp->scc_gsmrl, SCC_GSMRL_ENR | SCC_GSMRL_ENT);
}

static void cpm_uart_init_smc(struct uart_cpm_port *pinfo)
{
        smc_t __iomem *sp;
        smc_uart_t __iomem *up;

        pr_debug("CPM uart[%d]:init_smc\n", pinfo->port.line);

        sp = pinfo->smcp;
        up = pinfo->smcup;

        /* Store address */
        out_be16(&pinfo->smcup->smc_rbase,
                 (u8 __iomem *)pinfo->rx_bd_base - DPRAM_BASE);
        out_be16(&pinfo->smcup->smc_tbase,
                 (u8 __iomem *)pinfo->tx_bd_base - DPRAM_BASE);

/*
 *  In case SMC1 is being relocated...
 */
#if defined (CONFIG_I2C_SPI_SMC1_UCODE_PATCH)
        out_be16(&up->smc_rbptr, in_be16(&pinfo->smcup->smc_rbase));
        out_be16(&up->smc_tbptr, in_be16(&pinfo->smcup->smc_tbase));
        out_be32(&up->smc_rstate, 0);
        out_be32(&up->smc_tstate, 0);
        out_be16(&up->smc_brkcr, 1);              /* number of break chars */
        out_be16(&up->smc_brkec, 0);
#endif

        /* Set up the uart parameters in the
         * parameter ram.
         */
        cpm_set_smc_fcr(up);

        /* Using idle character time requires some additional tuning.  */
        out_be16(&up->smc_mrblr, pinfo->rx_fifosize);
        out_be16(&up->smc_maxidl, 0x10);
        out_be16(&up->smc_brklen, 0);
        out_be16(&up->smc_brkec, 0);
        out_be16(&up->smc_brkcr, 1);

        cpm_line_cr_cmd(pinfo, CPM_CR_INIT_TRX);

        /* Set UART mode, 8 bit, no parity, one stop.
         * Enable receive and transmit.
         */
        out_be16(&sp->smc_smcmr, smcr_mk_clen(9) | SMCMR_SM_UART);

        /* Enable only rx interrupts clear all pending events. */
        out_8(&sp->smc_smcm, 0);
        out_8(&sp->smc_smce, 0xff);

        setbits16(&sp->smc_smcmr, SMCMR_REN | SMCMR_TEN);
}

/*
 * Initialize port. This is called from early_console stuff
 * so we have to be careful here !
 */
static int cpm_uart_request_port(struct uart_port *port)
{
        struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;
        int ret;

        pr_debug("CPM uart[%d]:request port\n", port->line);

        if (pinfo->flags & FLAG_CONSOLE)
                return 0;

        if (IS_SMC(pinfo)) {
                clrbits8(&pinfo->smcp->smc_smcm, SMCM_RX | SMCM_TX);
                clrbits16(&pinfo->smcp->smc_smcmr, SMCMR_REN | SMCMR_TEN);
        } else {
                clrbits16(&pinfo->sccp->scc_sccm, UART_SCCM_TX | UART_SCCM_RX);
                clrbits32(&pinfo->sccp->scc_gsmrl, SCC_GSMRL_ENR | SCC_GSMRL_ENT);
        }

        ret = cpm_uart_allocbuf(pinfo, 0);

        if (ret)
                return ret;

        cpm_uart_initbd(pinfo);
        if (IS_SMC(pinfo))
                cpm_uart_init_smc(pinfo);
        else
                cpm_uart_init_scc(pinfo);

        return 0;
}

static void cpm_uart_release_port(struct uart_port *port)
{
        struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;

        if (!(pinfo->flags & FLAG_CONSOLE))
                cpm_uart_freebuf(pinfo);
}

/*
 * Configure/autoconfigure the port.
 */
static void cpm_uart_config_port(struct uart_port *port, int flags)
{
        pr_debug("CPM uart[%d]:config_port\n", port->line);

        if (flags & UART_CONFIG_TYPE) {
                port->type = PORT_CPM;
                cpm_uart_request_port(port);
        }
}

#if defined(CONFIG_CONSOLE_POLL) || defined(CONFIG_SERIAL_CPM_CONSOLE)
/*
 * Write a string to the serial port
 * Note that this is called with interrupts already disabled
 */
static void cpm_uart_early_write(struct uart_cpm_port *pinfo,
                const char *string, u_int count)
{
        unsigned int i;
        cbd_t __iomem *bdp, *bdbase;
        unsigned char *cpm_outp_addr;

        /* Get the address of the host memory buffer.
         */
        bdp = pinfo->tx_cur;
        bdbase = pinfo->tx_bd_base;

        /*
         * Now, do each character.  This is not as bad as it looks
         * since this is a holding FIFO and not a transmitting FIFO.
         * We could add the complexity of filling the entire transmit
         * buffer, but we would just wait longer between accesses......
         */
        for (i = 0; i < count; i++, string++) {
                /* Wait for transmitter fifo to empty.
                 * Ready indicates output is ready, and xmt is doing
                 * that, not that it is ready for us to send.
                 */
                while ((in_be16(&bdp->cbd_sc) & BD_SC_READY) != 0)
                        ;

                /* Send the character out.
                 * If the buffer address is in the CPM DPRAM, don't
                 * convert it.
                 */

                cpm_outp_addr = cpm2cpu_addr(in_be32(&bdp->cbd_bufaddr),
                                        pinfo);
                *cpm_outp_addr = *string;

                out_be16(&bdp->cbd_datlen, 1);
                setbits16(&bdp->cbd_sc, BD_SC_READY);

                if (in_be16(&bdp->cbd_sc) & BD_SC_WRAP)
                        bdp = bdbase;
                else
                        bdp++;

                /* if a LF, also do CR... */
                if (*string == 10) {
                        while ((in_be16(&bdp->cbd_sc) & BD_SC_READY) != 0)
                                ;

                        cpm_outp_addr = cpm2cpu_addr(in_be32(&bdp->cbd_bufaddr),
                                                pinfo);
                        *cpm_outp_addr = 13;

                        out_be16(&bdp->cbd_datlen, 1);
                        setbits16(&bdp->cbd_sc, BD_SC_READY);

                        if (in_be16(&bdp->cbd_sc) & BD_SC_WRAP)
                                bdp = bdbase;
                        else
                                bdp++;
                }
        }

        /*
         * Finally, Wait for transmitter & holding register to empty
         *  and restore the IER
         */
        while ((in_be16(&bdp->cbd_sc) & BD_SC_READY) != 0)
                ;

        pinfo->tx_cur = bdp;
}
#endif

#ifdef CONFIG_CONSOLE_POLL
/* Serial polling routines for writing and reading from the uart while
 * in an interrupt or debug context.
 */

#define GDB_BUF_SIZE    512     /* power of 2, please */

static char poll_buf[GDB_BUF_SIZE];
static char *pollp;
static int poll_chars;

static int poll_wait_key(char *obuf, struct uart_cpm_port *pinfo)
{
        u_char          c, *cp;
        volatile cbd_t  *bdp;
        int             i;

        /* Get the address of the host memory buffer.
         */
        bdp = pinfo->rx_cur;
        while (bdp->cbd_sc & BD_SC_EMPTY)
                ;

        /* If the buffer address is in the CPM DPRAM, don't
         * convert it.
         */
        cp = cpm2cpu_addr(bdp->cbd_bufaddr, pinfo);

        if (obuf) {
                i = c = bdp->cbd_datlen;
                while (i-- > 0)
                        *obuf++ = *cp++;
        } else
                c = *cp;
        bdp->cbd_sc &= ~(BD_SC_BR | BD_SC_FR | BD_SC_PR | BD_SC_OV | BD_SC_ID);
        bdp->cbd_sc |= BD_SC_EMPTY;

        if (bdp->cbd_sc & BD_SC_WRAP)
                bdp = pinfo->rx_bd_base;
        else
                bdp++;
        pinfo->rx_cur = (cbd_t *)bdp;

        return (int)c;
}

static int cpm_get_poll_char(struct uart_port *port)
{
        struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;

        if (!serial_polled) {
                serial_polled = 1;
                poll_chars = 0;
        }
        if (poll_chars <= 0) {
                poll_chars = poll_wait_key(poll_buf, pinfo);
                pollp = poll_buf;
        }
        poll_chars--;
        return *pollp++;
}

static void cpm_put_poll_char(struct uart_port *port,
                         unsigned char c)
{
        struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;
        static char ch[2];

        ch[0] = (char)c;
        cpm_uart_early_write(pinfo, ch, 1);
}
#endif /* CONFIG_CONSOLE_POLL */

static struct uart_ops cpm_uart_pops = {
        .tx_empty       = cpm_uart_tx_empty,
        .set_mctrl      = cpm_uart_set_mctrl,
        .get_mctrl      = cpm_uart_get_mctrl,
        .stop_tx        = cpm_uart_stop_tx,
        .start_tx       = cpm_uart_start_tx,
        .stop_rx        = cpm_uart_stop_rx,
        .enable_ms      = cpm_uart_enable_ms,
        .break_ctl      = cpm_uart_break_ctl,
        .startup        = cpm_uart_startup,
        .shutdown       = cpm_uart_shutdown,
        .set_termios    = cpm_uart_set_termios,
        .type           = cpm_uart_type,
        .release_port   = cpm_uart_release_port,
        .request_port   = cpm_uart_request_port,
        .config_port    = cpm_uart_config_port,
        .verify_port    = cpm_uart_verify_port,
#ifdef CONFIG_CONSOLE_POLL
        .poll_get_char = cpm_get_poll_char,
        .poll_put_char = cpm_put_poll_char,
#endif
};

struct uart_cpm_port cpm_uart_ports[UART_NR];

static int cpm_uart_init_port(struct device_node *np,
                              struct uart_cpm_port *pinfo)
{
        const u32 *data;
        void __iomem *mem, *pram;
        int len;
        int ret;
        int i;

        data = of_get_property(np, "clock", NULL);
        if (data) {
                struct clk *clk = clk_get(NULL, (const char*)data);
                if (!IS_ERR(clk))
                        pinfo->clk = clk;
        }
        if (!pinfo->clk) {
                data = of_get_property(np, "fsl,cpm-brg", &len);
                if (!data || len != 4) {
                        printk(KERN_ERR "CPM UART %s has no/invalid "
                                        "fsl,cpm-brg property.\n", np->name);
                        return -EINVAL;
                }
                pinfo->brg = *data;
        }

        data = of_get_property(np, "fsl,cpm-command", &len);
        if (!data || len != 4) {
                printk(KERN_ERR "CPM UART %s has no/invalid "
                                "fsl,cpm-command property.\n", np->name);
                return -EINVAL;
        }
        pinfo->command = *data;

        mem = of_iomap(np, 0);
        if (!mem)
                return -ENOMEM;

        if (of_device_is_compatible(np, "fsl,cpm1-scc-uart") ||
            of_device_is_compatible(np, "fsl,cpm2-scc-uart")) {
                pinfo->sccp = mem;
                pinfo->sccup = pram = cpm_uart_map_pram(pinfo, np);
        } else if (of_device_is_compatible(np, "fsl,cpm1-smc-uart") ||
                   of_device_is_compatible(np, "fsl,cpm2-smc-uart")) {
                pinfo->flags |= FLAG_SMC;
                pinfo->smcp = mem;
                pinfo->smcup = pram = cpm_uart_map_pram(pinfo, np);
        } else {
                ret = -ENODEV;
                goto out_mem;
        }

        if (!pram) {
                ret = -ENOMEM;
                goto out_mem;
        }

        pinfo->tx_nrfifos = TX_NUM_FIFO;
        pinfo->tx_fifosize = TX_BUF_SIZE;
        pinfo->rx_nrfifos = RX_NUM_FIFO;
        pinfo->rx_fifosize = RX_BUF_SIZE;

        pinfo->port.uartclk = ppc_proc_freq;
        pinfo->port.mapbase = (unsigned long)mem;
        pinfo->port.type = PORT_CPM;
        pinfo->port.ops = &cpm_uart_pops,
        pinfo->port.iotype = UPIO_MEM;
        pinfo->port.fifosize = pinfo->tx_nrfifos * pinfo->tx_fifosize;
        spin_lock_init(&pinfo->port.lock);

        pinfo->port.irq = of_irq_to_resource(np, 0, NULL);
        if (pinfo->port.irq == NO_IRQ) {
                ret = -EINVAL;
                goto out_pram;
        }

        for (i = 0; i < NUM_GPIOS; i++)
                pinfo->gpios[i] = of_get_gpio(np, i);

#ifdef CONFIG_PPC_EARLY_DEBUG_CPM
        udbg_putc = NULL;
#endif

        return cpm_uart_request_port(&pinfo->port);

out_pram:
        cpm_uart_unmap_pram(pinfo, pram);
out_mem:
        iounmap(mem);
        return ret;
}

#ifdef CONFIG_SERIAL_CPM_CONSOLE
/*
 *      Print a string to the serial port trying not to disturb
 *      any possible real use of the port...
 *
 *      Note that this is called with interrupts already disabled
 */
static void cpm_uart_console_write(struct console *co, const char *s,
                                   u_int count)
{
        struct uart_cpm_port *pinfo = &cpm_uart_ports[co->index];
        unsigned long flags;
        int nolock = oops_in_progress;

        if (unlikely(nolock)) {
                local_irq_save(flags);
        } else {
                spin_lock_irqsave(&pinfo->port.lock, flags);
        }

        cpm_uart_early_write(pinfo, s, count);

        if (unlikely(nolock)) {
                local_irq_restore(flags);
        } else {
                spin_unlock_irqrestore(&pinfo->port.lock, flags);
        }
}


static int __init cpm_uart_console_setup(struct console *co, char *options)
{
        int baud = 38400;
        int bits = 8;
        int parity = 'n';
        int flow = 'n';
        int ret;
        struct uart_cpm_port *pinfo;
        struct uart_port *port;

        struct device_node *np = NULL;
        int i = 0;

        if (co->index >= UART_NR) {
                printk(KERN_ERR "cpm_uart: console index %d too high\n",
                       co->index);
                return -ENODEV;
        }

        do {
                np = of_find_node_by_type(np, "serial");
                if (!np)
                        return -ENODEV;

                if (!of_device_is_compatible(np, "fsl,cpm1-smc-uart") &&
                    !of_device_is_compatible(np, "fsl,cpm1-scc-uart") &&
                    !of_device_is_compatible(np, "fsl,cpm2-smc-uart") &&
                    !of_device_is_compatible(np, "fsl,cpm2-scc-uart"))
                        i--;
        } while (i++ != co->index);

        pinfo = &cpm_uart_ports[co->index];

        pinfo->flags |= FLAG_CONSOLE;
        port = &pinfo->port;

        ret = cpm_uart_init_port(np, pinfo);
        of_node_put(np);
        if (ret)
                return ret;

        if (options) {
                uart_parse_options(options, &baud, &parity, &bits, &flow);
        } else {
                if ((baud = uart_baudrate()) == -1)
                        baud = 9600;
        }

        if (IS_SMC(pinfo)) {
                out_be16(&pinfo->smcup->smc_brkcr, 0);
                cpm_line_cr_cmd(pinfo, CPM_CR_STOP_TX);
                clrbits8(&pinfo->smcp->smc_smcm, SMCM_RX | SMCM_TX);
                clrbits16(&pinfo->smcp->smc_smcmr, SMCMR_REN | SMCMR_TEN);
        } else {
                out_be16(&pinfo->sccup->scc_brkcr, 0);
                cpm_line_cr_cmd(pinfo, CPM_CR_GRA_STOP_TX);
                clrbits16(&pinfo->sccp->scc_sccm, UART_SCCM_TX | UART_SCCM_RX);
                clrbits32(&pinfo->sccp->scc_gsmrl, SCC_GSMRL_ENR | SCC_GSMRL_ENT);
        }

        ret = cpm_uart_allocbuf(pinfo, 1);

        if (ret)
                return ret;

        cpm_uart_initbd(pinfo);

        if (IS_SMC(pinfo))
                cpm_uart_init_smc(pinfo);
        else
                cpm_uart_init_scc(pinfo);

        uart_set_options(port, co, baud, parity, bits, flow);
        cpm_line_cr_cmd(pinfo, CPM_CR_RESTART_TX);

        return 0;
}

static struct uart_driver cpm_reg;
static struct console cpm_scc_uart_console = {
        .name           = "ttyCPM",
        .write          = cpm_uart_console_write,
        .device         = uart_console_device,
        .setup          = cpm_uart_console_setup,
        .flags          = CON_PRINTBUFFER,
        .index          = -1,
        .data           = &cpm_reg,
};

static int __init cpm_uart_console_init(void)
{
        register_console(&cpm_scc_uart_console);
        return 0;
}

console_initcall(cpm_uart_console_init);

#define CPM_UART_CONSOLE        &cpm_scc_uart_console
#else
#define CPM_UART_CONSOLE        NULL
#endif

static struct uart_driver cpm_reg = {
        .owner          = THIS_MODULE,
        .driver_name    = "ttyCPM",
        .dev_name       = "ttyCPM",
        .major          = SERIAL_CPM_MAJOR,
        .minor          = SERIAL_CPM_MINOR,
        .cons           = CPM_UART_CONSOLE,
        .nr             = UART_NR,
};

static int probe_index;

static int cpm_uart_probe(struct platform_device *ofdev)
{
        int index = probe_index++;
        struct uart_cpm_port *pinfo = &cpm_uart_ports[index];
        int ret;

        pinfo->port.line = index;

        if (index >= UART_NR)
                return -ENODEV;

        dev_set_drvdata(&ofdev->dev, pinfo);

        /* initialize the device pointer for the port */
        pinfo->port.dev = &ofdev->dev;

        ret = cpm_uart_init_port(ofdev->dev.of_node, pinfo);
        if (ret)
                return ret;

        return uart_add_one_port(&cpm_reg, &pinfo->port);
}

static int cpm_uart_remove(struct platform_device *ofdev)
{
        struct uart_cpm_port *pinfo = dev_get_drvdata(&ofdev->dev);
        return uart_remove_one_port(&cpm_reg, &pinfo->port);
}

static struct of_device_id cpm_uart_match[] = {
        {
                .compatible = "fsl,cpm1-smc-uart",
        },
        {
                .compatible = "fsl,cpm1-scc-uart",
        },
        {
                .compatible = "fsl,cpm2-smc-uart",
        },
        {
                .compatible = "fsl,cpm2-scc-uart",
        },
        {}
};

static struct platform_driver cpm_uart_driver = {
        .driver = {
                .name = "cpm_uart",
                .owner = THIS_MODULE,
                .of_match_table = cpm_uart_match,
        },
        .probe = cpm_uart_probe,
        .remove = cpm_uart_remove,
 };

static int __init cpm_uart_init(void)
{
        int ret = uart_register_driver(&cpm_reg);
        if (ret)
                return ret;

        ret = platform_driver_register(&cpm_uart_driver);
        if (ret)
                uart_unregister_driver(&cpm_reg);

        return ret;
}

static void __exit cpm_uart_exit(void)
{
        platform_driver_unregister(&cpm_uart_driver);
        uart_unregister_driver(&cpm_reg);
}

module_init(cpm_uart_init);
module_exit(cpm_uart_exit);

MODULE_AUTHOR("Kumar Gala/Antoniou Pantelis");
MODULE_DESCRIPTION("CPM SCC/SMC port driver $Revision: 0.01 $");
MODULE_LICENSE("GPL");
MODULE_ALIAS_CHARDEV(SERIAL_CPM_MAJOR, SERIAL_CPM_MINOR);