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mpc52xx_uart.c

/*
 * Driver for the PSC of the Freescale MPC52xx PSCs configured as UARTs.
 *
 * FIXME According to the usermanual the status bits in the status register
 * are only updated when the peripherals access the FIFO and not when the
 * CPU access them. So since we use this bits to know when we stop writing
 * and reading, they may not be updated in-time and a race condition may
 * exists. But I haven't be able to prove this and I don't care. But if
 * any problem arises, it might worth checking. The TX/RX FIFO Stats
 * registers should be used in addition.
 * Update: Actually, they seem updated ... At least the bits we use.
 *
 *
 * Maintainer : Sylvain Munaut <tnt@246tNt.com>
 *
 * Some of the code has been inspired/copied from the 2.4 code written
 * by Dale Farnsworth <dfarnsworth@mvista.com>.
 *
 * Copyright (C) 2006 Secret Lab Technologies Ltd.
 *                    Grant Likely <grant.likely@secretlab.ca>
 * Copyright (C) 2004-2006 Sylvain Munaut <tnt@246tNt.com>
 * Copyright (C) 2003 MontaVista, Software, Inc.
 *
 * This file is licensed under the terms of the GNU General Public License
 * version 2. This program is licensed "as is" without any warranty of any
 * kind, whether express or implied.
 */

/* Platform device Usage :
 *
 * Since PSCs can have multiple function, the correct driver for each one
 * is selected by calling mpc52xx_match_psc_function(...). The function
 * handled by this driver is "uart".
 *
 * The driver init all necessary registers to place the PSC in uart mode without
 * DCD. However, the pin multiplexing aren't changed and should be set either
 * by the bootloader or in the platform init code.
 *
 * The idx field must be equal to the PSC index ( e.g. 0 for PSC1, 1 for PSC2,
 * and so on). So the PSC1 is mapped to /dev/ttyPSC0, PSC2 to /dev/ttyPSC1 and
 * so on. But be warned, it's an ABSOLUTE REQUIREMENT ! This is needed mainly
 * fpr the console code : without this 1:1 mapping, at early boot time, when we
 * are parsing the kernel args console=ttyPSC?, we wouldn't know which PSC it
 * will be mapped to.
 */

/* OF Platform device Usage :
 *
 * This driver is only used for PSCs configured in uart mode.  The device
 * tree will have a node for each PSC in uart mode w/ device_type = "serial"
 * and "mpc52xx-psc-uart" in the compatible string
 *
 * By default, PSC devices are enumerated in the order they are found.  However
 * a particular PSC number can be forces by adding 'device_no = <port#>'
 * to the device node.
 *
 * The driver init all necessary registers to place the PSC in uart mode without
 * DCD. However, the pin multiplexing aren't changed and should be set either
 * by the bootloader or in the platform init code.
 */

#undef DEBUG

#include <linux/device.h>
#include <linux/module.h>
#include <linux/tty.h>
#include <linux/serial.h>
#include <linux/sysrq.h>
#include <linux/console.h>

#include <asm/delay.h>
#include <asm/io.h>

#if defined(CONFIG_PPC_MERGE)
#include <asm/of_platform.h>
#else
#include <linux/platform_device.h>
#endif

#include <asm/mpc52xx.h>
#include <asm/mpc52xx_psc.h>

#if defined(CONFIG_SERIAL_MPC52xx_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif

#include <linux/serial_core.h>


/* We've been assigned a range on the "Low-density serial ports" major */
#define SERIAL_PSC_MAJOR      204
#define SERIAL_PSC_MINOR      148


#define ISR_PASS_LIMIT 256    /* Max number of iteration in the interrupt */


static struct uart_port mpc52xx_uart_ports[MPC52xx_PSC_MAXNUM];
      /* Rem: - We use the read_status_mask as a shadow of
       *        psc->mpc52xx_psc_imr
       *      - It's important that is array is all zero on start as we
       *        use it to know if it's initialized or not ! If it's not sure
       *        it's cleared, then a memset(...,0,...) should be added to
       *        the console_init
       */
#if defined(CONFIG_PPC_MERGE)
/* lookup table for matching device nodes to index numbers */
static struct device_node *mpc52xx_uart_nodes[MPC52xx_PSC_MAXNUM];

static void mpc52xx_uart_of_enumerate(void);
#endif

#define PSC(port) ((struct mpc52xx_psc __iomem *)((port)->membase))


/* Forward declaration of the interruption handling routine */
static irqreturn_t mpc52xx_uart_int(int irq,void *dev_id);


/* Simple macro to test if a port is console or not. This one is taken
 * for serial_core.c and maybe should be moved to serial_core.h ? */
#ifdef CONFIG_SERIAL_CORE_CONSOLE
#define uart_console(port)    ((port)->cons && (port)->cons->index == (port)->line)
#else
#define uart_console(port)    (0)
#endif

#if defined(CONFIG_PPC_MERGE)
static struct of_device_id mpc52xx_uart_of_match[] = {
      { .type = "serial", .compatible = "mpc5200-psc-uart", },
      {},
};
#endif


/* ======================================================================== */
/* UART operations                                                          */
/* ======================================================================== */

static unsigned int
mpc52xx_uart_tx_empty(struct uart_port *port)
{
      int status = in_be16(&PSC(port)->mpc52xx_psc_status);
      return (status & MPC52xx_PSC_SR_TXEMP) ? TIOCSER_TEMT : 0;
}

static void
mpc52xx_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
      /* Not implemented */
}

static unsigned int
mpc52xx_uart_get_mctrl(struct uart_port *port)
{
      /* Not implemented */
      return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
}

static void
mpc52xx_uart_stop_tx(struct uart_port *port)
{
      /* port->lock taken by caller */
      port->read_status_mask &= ~MPC52xx_PSC_IMR_TXRDY;
      out_be16(&PSC(port)->mpc52xx_psc_imr,port->read_status_mask);
}

static void
mpc52xx_uart_start_tx(struct uart_port *port)
{
      /* port->lock taken by caller */
      port->read_status_mask |= MPC52xx_PSC_IMR_TXRDY;
      out_be16(&PSC(port)->mpc52xx_psc_imr,port->read_status_mask);
}

static void
mpc52xx_uart_send_xchar(struct uart_port *port, char ch)
{
      unsigned long flags;
      spin_lock_irqsave(&port->lock, flags);

      port->x_char = ch;
      if (ch) {
            /* Make sure tx interrupts are on */
            /* Truly necessary ??? They should be anyway */
            port->read_status_mask |= MPC52xx_PSC_IMR_TXRDY;
            out_be16(&PSC(port)->mpc52xx_psc_imr,port->read_status_mask);
      }

      spin_unlock_irqrestore(&port->lock, flags);
}

static void
mpc52xx_uart_stop_rx(struct uart_port *port)
{
      /* port->lock taken by caller */
      port->read_status_mask &= ~MPC52xx_PSC_IMR_RXRDY;
      out_be16(&PSC(port)->mpc52xx_psc_imr,port->read_status_mask);
}

static void
mpc52xx_uart_enable_ms(struct uart_port *port)
{
      /* Not implemented */
}

static void
mpc52xx_uart_break_ctl(struct uart_port *port, int ctl)
{
      unsigned long flags;
      spin_lock_irqsave(&port->lock, flags);

      if ( ctl == -1 )
            out_8(&PSC(port)->command,MPC52xx_PSC_START_BRK);
      else
            out_8(&PSC(port)->command,MPC52xx_PSC_STOP_BRK);

      spin_unlock_irqrestore(&port->lock, flags);
}

static int
mpc52xx_uart_startup(struct uart_port *port)
{
      struct mpc52xx_psc __iomem *psc = PSC(port);
      int ret;

      /* Request IRQ */
      ret = request_irq(port->irq, mpc52xx_uart_int,
            IRQF_DISABLED | IRQF_SAMPLE_RANDOM, "mpc52xx_psc_uart", port);
      if (ret)
            return ret;

      /* Reset/activate the port, clear and enable interrupts */
      out_8(&psc->command,MPC52xx_PSC_RST_RX);
      out_8(&psc->command,MPC52xx_PSC_RST_TX);

      out_be32(&psc->sicr,0); /* UART mode DCD ignored */

      out_be16(&psc->mpc52xx_psc_clock_select, 0xdd00); /* /16 prescaler on */

      out_8(&psc->rfcntl, 0x00);
      out_be16(&psc->rfalarm, 0x1ff);
      out_8(&psc->tfcntl, 0x07);
      out_be16(&psc->tfalarm, 0x80);

      port->read_status_mask |= MPC52xx_PSC_IMR_RXRDY | MPC52xx_PSC_IMR_TXRDY;
      out_be16(&psc->mpc52xx_psc_imr,port->read_status_mask);

      out_8(&psc->command,MPC52xx_PSC_TX_ENABLE);
      out_8(&psc->command,MPC52xx_PSC_RX_ENABLE);

      return 0;
}

static void
mpc52xx_uart_shutdown(struct uart_port *port)
{
      struct mpc52xx_psc __iomem *psc = PSC(port);

      /* Shut down the port.  Leave TX active if on a console port */
      out_8(&psc->command,MPC52xx_PSC_RST_RX);
      if (!uart_console(port))
            out_8(&psc->command,MPC52xx_PSC_RST_TX);

      port->read_status_mask = 0;
      out_be16(&psc->mpc52xx_psc_imr,port->read_status_mask);

      /* Release interrupt */
      free_irq(port->irq, port);
}

static void
mpc52xx_uart_set_termios(struct uart_port *port, struct ktermios *new,
                         struct ktermios *old)
{
      struct mpc52xx_psc __iomem *psc = PSC(port);
      unsigned long flags;
      unsigned char mr1, mr2;
      unsigned short ctr;
      unsigned int j, baud, quot;

      /* Prepare what we're gonna write */
      mr1 = 0;

      switch (new->c_cflag & CSIZE) {
            case CS5:   mr1 |= MPC52xx_PSC_MODE_5_BITS;
                        break;
            case CS6:   mr1 |= MPC52xx_PSC_MODE_6_BITS;
                        break;
            case CS7:   mr1 |= MPC52xx_PSC_MODE_7_BITS;
                        break;
            case CS8:
            default:    mr1 |= MPC52xx_PSC_MODE_8_BITS;
      }

      if (new->c_cflag & PARENB) {
            mr1 |= (new->c_cflag & PARODD) ?
                  MPC52xx_PSC_MODE_PARODD : MPC52xx_PSC_MODE_PAREVEN;
      } else
            mr1 |= MPC52xx_PSC_MODE_PARNONE;


      mr2 = 0;

      if (new->c_cflag & CSTOPB)
            mr2 |= MPC52xx_PSC_MODE_TWO_STOP;
      else
            mr2 |= ((new->c_cflag & CSIZE) == CS5) ?
                  MPC52xx_PSC_MODE_ONE_STOP_5_BITS :
                  MPC52xx_PSC_MODE_ONE_STOP;


      baud = uart_get_baud_rate(port, new, old, 0, port->uartclk/16);
      quot = uart_get_divisor(port, baud);
      ctr = quot & 0xffff;

      /* Get the lock */
      spin_lock_irqsave(&port->lock, flags);

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

      /* Do our best to flush TX & RX, so we don't loose anything */
      /* But we don't wait indefinitly ! */
      j = 5000000;      /* Maximum wait */
      /* FIXME Can't receive chars since set_termios might be called at early
       * boot for the console, all stuff is not yet ready to receive at that
       * time and that just makes the kernel oops */
      /* while (j-- && mpc52xx_uart_int_rx_chars(port)); */
      while (!(in_be16(&psc->mpc52xx_psc_status) & MPC52xx_PSC_SR_TXEMP) &&
             --j)
            udelay(1);

      if (!j)
            printk(     KERN_ERR "mpc52xx_uart.c: "
                  "Unable to flush RX & TX fifos in-time in set_termios."
                  "Some chars may have been lost.\n" );

      /* Reset the TX & RX */
      out_8(&psc->command,MPC52xx_PSC_RST_RX);
      out_8(&psc->command,MPC52xx_PSC_RST_TX);

      /* Send new mode settings */
      out_8(&psc->command,MPC52xx_PSC_SEL_MODE_REG_1);
      out_8(&psc->mode,mr1);
      out_8(&psc->mode,mr2);
      out_8(&psc->ctur,ctr >> 8);
      out_8(&psc->ctlr,ctr & 0xff);

      /* Reenable TX & RX */
      out_8(&psc->command,MPC52xx_PSC_TX_ENABLE);
      out_8(&psc->command,MPC52xx_PSC_RX_ENABLE);

      /* We're all set, release the lock */
      spin_unlock_irqrestore(&port->lock, flags);
}

static const char *
mpc52xx_uart_type(struct uart_port *port)
{
      return port->type == PORT_MPC52xx ? "MPC52xx PSC" : NULL;
}

static void
mpc52xx_uart_release_port(struct uart_port *port)
{
      if (port->flags & UPF_IOREMAP) { /* remapped by us ? */
            iounmap(port->membase);
            port->membase = NULL;
      }

      release_mem_region(port->mapbase, sizeof(struct mpc52xx_psc));
}

static int
mpc52xx_uart_request_port(struct uart_port *port)
{
      int err;

      if (port->flags & UPF_IOREMAP) /* Need to remap ? */
            port->membase = ioremap(port->mapbase,
                                    sizeof(struct mpc52xx_psc));

      if (!port->membase)
            return -EINVAL;

      err = request_mem_region(port->mapbase, sizeof(struct mpc52xx_psc),
                  "mpc52xx_psc_uart") != NULL ? 0 : -EBUSY;

      if (err && (port->flags & UPF_IOREMAP)) {
            iounmap(port->membase);
            port->membase = NULL;
      }

      return err;
}

static void
mpc52xx_uart_config_port(struct uart_port *port, int flags)
{
      if ( (flags & UART_CONFIG_TYPE) &&
           (mpc52xx_uart_request_port(port) == 0) )
            port->type = PORT_MPC52xx;
}

static int
mpc52xx_uart_verify_port(struct uart_port *port, struct serial_struct *ser)
{
      if ( ser->type != PORT_UNKNOWN && ser->type != PORT_MPC52xx )
            return -EINVAL;

      if ( (ser->irq != port->irq) ||
           (ser->io_type != SERIAL_IO_MEM) ||
           (ser->baud_base != port->uartclk)  ||
           (ser->iomem_base != (void*)port->mapbase) ||
           (ser->hub6 != 0 ) )
            return -EINVAL;

      return 0;
}


static struct uart_ops mpc52xx_uart_ops = {
      .tx_empty   = mpc52xx_uart_tx_empty,
      .set_mctrl  = mpc52xx_uart_set_mctrl,
      .get_mctrl  = mpc52xx_uart_get_mctrl,
      .stop_tx    = mpc52xx_uart_stop_tx,
      .start_tx   = mpc52xx_uart_start_tx,
      .send_xchar = mpc52xx_uart_send_xchar,
      .stop_rx    = mpc52xx_uart_stop_rx,
      .enable_ms  = mpc52xx_uart_enable_ms,
      .break_ctl  = mpc52xx_uart_break_ctl,
      .startup    = mpc52xx_uart_startup,
      .shutdown   = mpc52xx_uart_shutdown,
      .set_termios      = mpc52xx_uart_set_termios,
/*    .pm         = mpc52xx_uart_pm,            Not supported yet */
/*    .set_wake   = mpc52xx_uart_set_wake,      Not supported yet */
      .type       = mpc52xx_uart_type,
      .release_port     = mpc52xx_uart_release_port,
      .request_port     = mpc52xx_uart_request_port,
      .config_port      = mpc52xx_uart_config_port,
      .verify_port      = mpc52xx_uart_verify_port
};


/* ======================================================================== */
/* Interrupt handling                                                       */
/* ======================================================================== */

static inline int
mpc52xx_uart_int_rx_chars(struct uart_port *port)
{
      struct tty_struct *tty = port->info->tty;
      unsigned char ch, flag;
      unsigned short status;

      /* While we can read, do so ! */
      while ( (status = in_be16(&PSC(port)->mpc52xx_psc_status)) &
              MPC52xx_PSC_SR_RXRDY) {

            /* Get the char */
            ch = in_8(&PSC(port)->mpc52xx_psc_buffer_8);

            /* Handle sysreq char */
#ifdef SUPPORT_SYSRQ
            if (uart_handle_sysrq_char(port, ch)) {
                  port->sysrq = 0;
                  continue;
            }
#endif

            /* Store it */

            flag = TTY_NORMAL;
            port->icount.rx++;

            if ( status & (MPC52xx_PSC_SR_PE |
                           MPC52xx_PSC_SR_FE |
                           MPC52xx_PSC_SR_RB) ) {

                  if (status & MPC52xx_PSC_SR_RB) {
                        flag = TTY_BREAK;
                        uart_handle_break(port);
                  } else if (status & MPC52xx_PSC_SR_PE)
                        flag = TTY_PARITY;
                  else if (status & MPC52xx_PSC_SR_FE)
                        flag = TTY_FRAME;

                  /* Clear error condition */
                  out_8(&PSC(port)->command,MPC52xx_PSC_RST_ERR_STAT);

            }
            tty_insert_flip_char(tty, ch, flag);
            if (status & MPC52xx_PSC_SR_OE) {
                  /*
                   * Overrun is special, since it's
                   * reported immediately, and doesn't
                   * affect the current character
                   */
                  tty_insert_flip_char(tty, 0, TTY_OVERRUN);
            }
      }

      tty_flip_buffer_push(tty);

      return in_be16(&PSC(port)->mpc52xx_psc_status) & MPC52xx_PSC_SR_RXRDY;
}

static inline int
mpc52xx_uart_int_tx_chars(struct uart_port *port)
{
      struct circ_buf *xmit = &port->info->xmit;

      /* Process out of band chars */
      if (port->x_char) {
            out_8(&PSC(port)->mpc52xx_psc_buffer_8, port->x_char);
            port->icount.tx++;
            port->x_char = 0;
            return 1;
      }

      /* Nothing to do ? */
      if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
            mpc52xx_uart_stop_tx(port);
            return 0;
      }

      /* Send chars */
      while (in_be16(&PSC(port)->mpc52xx_psc_status) & MPC52xx_PSC_SR_TXRDY) {
            out_8(&PSC(port)->mpc52xx_psc_buffer_8, xmit->buf[xmit->tail]);
            xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
            port->icount.tx++;
            if (uart_circ_empty(xmit))
                  break;
      }

      /* Wake up */
      if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
            uart_write_wakeup(port);

      /* Maybe we're done after all */
      if (uart_circ_empty(xmit)) {
            mpc52xx_uart_stop_tx(port);
            return 0;
      }

      return 1;
}

static irqreturn_t
mpc52xx_uart_int(int irq, void *dev_id)
{
      struct uart_port *port = dev_id;
      unsigned long pass = ISR_PASS_LIMIT;
      unsigned int keepgoing;
      unsigned short status;

      spin_lock(&port->lock);

      /* While we have stuff to do, we continue */
      do {
            /* If we don't find anything to do, we stop */
            keepgoing = 0;

            /* Read status */
            status = in_be16(&PSC(port)->mpc52xx_psc_isr);
            status &= port->read_status_mask;

            /* Do we need to receive chars ? */
            /* For this RX interrupts must be on and some chars waiting */
            if ( status & MPC52xx_PSC_IMR_RXRDY )
                  keepgoing |= mpc52xx_uart_int_rx_chars(port);

            /* Do we need to send chars ? */
            /* For this, TX must be ready and TX interrupt enabled */
            if ( status & MPC52xx_PSC_IMR_TXRDY )
                  keepgoing |= mpc52xx_uart_int_tx_chars(port);

            /* Limit number of iteration */
            if ( !(--pass) )
                  keepgoing = 0;

      } while (keepgoing);

      spin_unlock(&port->lock);

      return IRQ_HANDLED;
}


/* ======================================================================== */
/* Console ( if applicable )                                                */
/* ======================================================================== */

#ifdef CONFIG_SERIAL_MPC52xx_CONSOLE

static void __init
mpc52xx_console_get_options(struct uart_port *port,
                            int *baud, int *parity, int *bits, int *flow)
{
      struct mpc52xx_psc __iomem *psc = PSC(port);
      unsigned char mr1;

      pr_debug("mpc52xx_console_get_options(port=%p)\n", port);

      /* Read the mode registers */
      out_8(&psc->command,MPC52xx_PSC_SEL_MODE_REG_1);
      mr1 = in_8(&psc->mode);

      /* CT{U,L}R are write-only ! */
      *baud = CONFIG_SERIAL_MPC52xx_CONSOLE_BAUD;
#if !defined(CONFIG_PPC_MERGE)
      if (__res.bi_baudrate)
            *baud = __res.bi_baudrate;
#endif

      /* Parse them */
      switch (mr1 & MPC52xx_PSC_MODE_BITS_MASK) {
            case MPC52xx_PSC_MODE_5_BITS: *bits = 5; break;
            case MPC52xx_PSC_MODE_6_BITS: *bits = 6; break;
            case MPC52xx_PSC_MODE_7_BITS: *bits = 7; break;
            case MPC52xx_PSC_MODE_8_BITS:
            default:                *bits = 8;
      }

      if (mr1 & MPC52xx_PSC_MODE_PARNONE)
            *parity = 'n';
      else
            *parity = mr1 & MPC52xx_PSC_MODE_PARODD ? 'o' : 'e';
}

static void
mpc52xx_console_write(struct console *co, const char *s, unsigned int count)
{
      struct uart_port *port = &mpc52xx_uart_ports[co->index];
      struct mpc52xx_psc __iomem *psc = PSC(port);
      unsigned int i, j;

      /* Disable interrupts */
      out_be16(&psc->mpc52xx_psc_imr, 0);

      /* Wait the TX buffer to be empty */
      j = 5000000;      /* Maximum wait */
      while (!(in_be16(&psc->mpc52xx_psc_status) & MPC52xx_PSC_SR_TXEMP) &&
             --j)
            udelay(1);

      /* Write all the chars */
      for (i = 0; i < count; i++, s++) {
            /* Line return handling */
            if (*s == '\n')
                  out_8(&psc->mpc52xx_psc_buffer_8, '\r');

            /* Send the char */
            out_8(&psc->mpc52xx_psc_buffer_8, *s);

            /* Wait the TX buffer to be empty */
            j = 20000;  /* Maximum wait */
            while (!(in_be16(&psc->mpc52xx_psc_status) &
                     MPC52xx_PSC_SR_TXEMP) && --j)
                  udelay(1);
      }

      /* Restore interrupt state */
      out_be16(&psc->mpc52xx_psc_imr, port->read_status_mask);
}

#if !defined(CONFIG_PPC_MERGE)
static int __init
mpc52xx_console_setup(struct console *co, char *options)
{
      struct uart_port *port = &mpc52xx_uart_ports[co->index];

      int baud = CONFIG_SERIAL_MPC52xx_CONSOLE_BAUD;
      int bits = 8;
      int parity = 'n';
      int flow = 'n';

      if (co->index < 0 || co->index >= MPC52xx_PSC_MAXNUM)
            return -EINVAL;

      /* Basic port init. Needed since we use some uart_??? func before
       * real init for early access */
      spin_lock_init(&port->lock);
      port->uartclk     = __res.bi_ipbfreq / 2; /* Look at CTLR doc */
      port->ops   = &mpc52xx_uart_ops;
      port->mapbase     = MPC52xx_PA(MPC52xx_PSCx_OFFSET(co->index+1));

      /* We ioremap ourself */
      port->membase = ioremap(port->mapbase, MPC52xx_PSC_SIZE);
      if (port->membase == NULL)
            return -EINVAL;

      /* Setup the port parameters accoding to options */
      if (options)
            uart_parse_options(options, &baud, &parity, &bits, &flow);
      else
            mpc52xx_console_get_options(port, &baud, &parity, &bits, &flow);

      return uart_set_options(port, co, baud, parity, bits, flow);
}

#else

static int __init
mpc52xx_console_setup(struct console *co, char *options)
{
      struct uart_port *port = &mpc52xx_uart_ports[co->index];
      struct device_node *np = mpc52xx_uart_nodes[co->index];
      unsigned int ipb_freq;
      struct resource res;
      int ret;

      int baud = CONFIG_SERIAL_MPC52xx_CONSOLE_BAUD;
      int bits = 8;
      int parity = 'n';
      int flow = 'n';

      pr_debug("mpc52xx_console_setup co=%p, co->index=%i, options=%s\n",
             co, co->index, options);

      if ((co->index < 0) || (co->index > MPC52xx_PSC_MAXNUM)) {
            pr_debug("PSC%x out of range\n", co->index);
            return -EINVAL;
      }

      if (!np) {
            pr_debug("PSC%x not found in device tree\n", co->index);
            return -EINVAL;
      }

      pr_debug("Console on ttyPSC%x is %s\n",
               co->index, mpc52xx_uart_nodes[co->index]->full_name);

      /* Fetch register locations */
      if ((ret = of_address_to_resource(np, 0, &res)) != 0) {
            pr_debug("Could not get resources for PSC%x\n", co->index);
            return ret;
      }

      /* Search for bus-frequency property in this node or a parent */
      if ((ipb_freq = mpc52xx_find_ipb_freq(np)) == 0) {
            pr_debug("Could not find IPB bus frequency!\n");
            return -EINVAL;
      }

      /* Basic port init. Needed since we use some uart_??? func before
       * real init for early access */
      spin_lock_init(&port->lock);
      port->uartclk     = ipb_freq / 2;
      port->ops   = &mpc52xx_uart_ops;
      port->mapbase = res.start;
      port->membase = ioremap(res.start, sizeof(struct mpc52xx_psc));
      port->irq = irq_of_parse_and_map(np, 0);

      if (port->membase == NULL)
            return -EINVAL;

      pr_debug("mpc52xx-psc uart at %p, mapped to %p, irq=%x, freq=%i\n",
               (void*)port->mapbase, port->membase, port->irq, port->uartclk);

      /* Setup the port parameters accoding to options */
      if (options)
            uart_parse_options(options, &baud, &parity, &bits, &flow);
      else
            mpc52xx_console_get_options(port, &baud, &parity, &bits, &flow);

      pr_debug("Setting console parameters: %i %i%c1 flow=%c\n",
               baud, bits, parity, flow);

      return uart_set_options(port, co, baud, parity, bits, flow);
}
#endif /* defined(CONFIG_PPC_MERGE) */


static struct uart_driver mpc52xx_uart_driver;

static struct console mpc52xx_console = {
      .name = "ttyPSC",
      .write      = mpc52xx_console_write,
      .device     = uart_console_device,
      .setup      = mpc52xx_console_setup,
      .flags      = CON_PRINTBUFFER,
      .index      = -1, /* Specified on the cmdline (e.g. console=ttyPSC0 ) */
      .data = &mpc52xx_uart_driver,
};


static int __init
mpc52xx_console_init(void)
{
#if defined(CONFIG_PPC_MERGE)
      mpc52xx_uart_of_enumerate();
#endif
      register_console(&mpc52xx_console);
      return 0;
}

console_initcall(mpc52xx_console_init);

#define MPC52xx_PSC_CONSOLE &mpc52xx_console
#else
#define MPC52xx_PSC_CONSOLE NULL
#endif


/* ======================================================================== */
/* UART Driver                                                              */
/* ======================================================================== */

static struct uart_driver mpc52xx_uart_driver = {
      .owner            = THIS_MODULE,
      .driver_name      = "mpc52xx_psc_uart",
      .dev_name   = "ttyPSC",
      .major            = SERIAL_PSC_MAJOR,
      .minor            = SERIAL_PSC_MINOR,
      .nr         = MPC52xx_PSC_MAXNUM,
      .cons       = MPC52xx_PSC_CONSOLE,
};


#if !defined(CONFIG_PPC_MERGE)
/* ======================================================================== */
/* Platform Driver                                                          */
/* ======================================================================== */

static int __devinit
mpc52xx_uart_probe(struct platform_device *dev)
{
      struct resource *res = dev->resource;

      struct uart_port *port = NULL;
      int i, idx, ret;

      /* Check validity & presence */
      idx = dev->id;
      if (idx < 0 || idx >= MPC52xx_PSC_MAXNUM)
            return -EINVAL;

      if (!mpc52xx_match_psc_function(idx,"uart"))
            return -ENODEV;

      /* Init the port structure */
      port = &mpc52xx_uart_ports[idx];

      spin_lock_init(&port->lock);
      port->uartclk     = __res.bi_ipbfreq / 2; /* Look at CTLR doc */
      port->fifosize    = 512;
      port->iotype      = UPIO_MEM;
      port->flags = UPF_BOOT_AUTOCONF |
                    ( uart_console(port) ? 0 : UPF_IOREMAP );
      port->line  = idx;
      port->ops   = &mpc52xx_uart_ops;
      port->dev   = &dev->dev;

      /* Search for IRQ and mapbase */
      for (i=0 ; i<dev->num_resources ; i++, res++) {
            if (res->flags & IORESOURCE_MEM)
                  port->mapbase = res->start;
            else if (res->flags & IORESOURCE_IRQ)
                  port->irq = res->start;
      }
      if (!port->irq || !port->mapbase)
            return -EINVAL;

      /* Add the port to the uart sub-system */
      ret = uart_add_one_port(&mpc52xx_uart_driver, port);
      if (!ret)
            platform_set_drvdata(dev, (void*)port);

      return ret;
}

static int
mpc52xx_uart_remove(struct platform_device *dev)
{
      struct uart_port *port = (struct uart_port *) platform_get_drvdata(dev);

      platform_set_drvdata(dev, NULL);

      if (port)
            uart_remove_one_port(&mpc52xx_uart_driver, port);

      return 0;
}

#ifdef CONFIG_PM
static int
mpc52xx_uart_suspend(struct platform_device *dev, pm_message_t state)
{
      struct uart_port *port = (struct uart_port *) platform_get_drvdata(dev);

      if (port)
            uart_suspend_port(&mpc52xx_uart_driver, port);

      return 0;
}

static int
mpc52xx_uart_resume(struct platform_device *dev)
{
      struct uart_port *port = (struct uart_port *) platform_get_drvdata(dev);

      if (port)
            uart_resume_port(&mpc52xx_uart_driver, port);

      return 0;
}
#endif


static struct platform_driver mpc52xx_uart_platform_driver = {
      .probe            = mpc52xx_uart_probe,
      .remove           = mpc52xx_uart_remove,
#ifdef CONFIG_PM
      .suspend    = mpc52xx_uart_suspend,
      .resume           = mpc52xx_uart_resume,
#endif
      .driver           = {
            .name = "mpc52xx-psc",
      },
};
#endif /* !defined(CONFIG_PPC_MERGE) */


#if defined(CONFIG_PPC_MERGE)
/* ======================================================================== */
/* OF Platform Driver                                                       */
/* ======================================================================== */

static int __devinit
mpc52xx_uart_of_probe(struct of_device *op, const struct of_device_id *match)
{
      int idx = -1;
      unsigned int ipb_freq;
      struct uart_port *port = NULL;
      struct resource res;
      int ret;

      dev_dbg(&op->dev, "mpc52xx_uart_probe(op=%p, match=%p)\n", op, match);

      /* Check validity & presence */
      for (idx = 0; idx < MPC52xx_PSC_MAXNUM; idx++)
            if (mpc52xx_uart_nodes[idx] == op->node)
                  break;
      if (idx >= MPC52xx_PSC_MAXNUM)
            return -EINVAL;
      pr_debug("Found %s assigned to ttyPSC%x\n",
               mpc52xx_uart_nodes[idx]->full_name, idx);

      /* Search for bus-frequency property in this node or a parent */
      if ((ipb_freq = mpc52xx_find_ipb_freq(op->node)) == 0) {
            dev_dbg(&op->dev, "Could not find IPB bus frequency!\n");
            return -EINVAL;
      }

      /* Init the port structure */
      port = &mpc52xx_uart_ports[idx];

      spin_lock_init(&port->lock);
      port->uartclk     = ipb_freq / 2;
      port->fifosize    = 512;
      port->iotype      = UPIO_MEM;
      port->flags = UPF_BOOT_AUTOCONF |
                    ( uart_console(port) ? 0 : UPF_IOREMAP );
      port->line  = idx;
      port->ops   = &mpc52xx_uart_ops;
      port->dev   = &op->dev;

      /* Search for IRQ and mapbase */
      if ((ret = of_address_to_resource(op->node, 0, &res)) != 0)
            return ret;

      port->mapbase = res.start;
      port->irq = irq_of_parse_and_map(op->node, 0);

      dev_dbg(&op->dev, "mpc52xx-psc uart at %p, irq=%x, freq=%i\n",
              (void*)port->mapbase, port->irq, port->uartclk);

      if ((port->irq==NO_IRQ) || !port->mapbase) {
            printk(KERN_ERR "Could not allocate resources for PSC\n");
            return -EINVAL;
      }

      /* Add the port to the uart sub-system */
      ret = uart_add_one_port(&mpc52xx_uart_driver, port);
      if (!ret)
            dev_set_drvdata(&op->dev, (void*)port);

      return ret;
}

static int
mpc52xx_uart_of_remove(struct of_device *op)
{
      struct uart_port *port = dev_get_drvdata(&op->dev);
      dev_set_drvdata(&op->dev, NULL);

      if (port) {
            uart_remove_one_port(&mpc52xx_uart_driver, port);
            irq_dispose_mapping(port->irq);
      }

      return 0;
}

#ifdef CONFIG_PM
static int
mpc52xx_uart_of_suspend(struct of_device *op, pm_message_t state)
{
      struct uart_port *port = (struct uart_port *) dev_get_drvdata(&op->dev);

      if (port)
            uart_suspend_port(&mpc52xx_uart_driver, port);

      return 0;
}

static int
mpc52xx_uart_of_resume(struct of_device *op)
{
      struct uart_port *port = (struct uart_port *) dev_get_drvdata(&op->dev);

      if (port)
            uart_resume_port(&mpc52xx_uart_driver, port);

      return 0;
}
#endif

static void
mpc52xx_uart_of_assign(struct device_node *np, int idx)
{
      int free_idx = -1;
      int i;

      /* Find the first free node */
      for (i = 0; i < MPC52xx_PSC_MAXNUM; i++) {
            if (mpc52xx_uart_nodes[i] == NULL) {
                  free_idx = i;
                  break;
            }
      }

      if ((idx < 0) || (idx >= MPC52xx_PSC_MAXNUM))
            idx = free_idx;

      if (idx < 0)
            return; /* No free slot; abort */

      /* If the slot is already occupied, then swap slots */
      if (mpc52xx_uart_nodes[idx] && (free_idx != -1))
            mpc52xx_uart_nodes[free_idx] = mpc52xx_uart_nodes[idx];
      mpc52xx_uart_nodes[idx] = np;
}

static void
mpc52xx_uart_of_enumerate(void)
{
      static int enum_done = 0;
      struct device_node *np;
      const unsigned int *devno;
      int i;

      if (enum_done)
            return;

      for_each_node_by_type(np, "serial") {
            if (!of_match_node(mpc52xx_uart_of_match, np))
                  continue;

            /* Is a particular device number requested? */
            devno = of_get_property(np, "port-number", NULL);
            mpc52xx_uart_of_assign(of_node_get(np), devno ? *devno : -1);
      }

      enum_done = 1;

      for (i = 0; i < MPC52xx_PSC_MAXNUM; i++) {
            if (mpc52xx_uart_nodes[i])
                  pr_debug("%s assigned to ttyPSC%x\n",
                           mpc52xx_uart_nodes[i]->full_name, i);
      }
}

MODULE_DEVICE_TABLE(of, mpc52xx_uart_of_match);

static struct of_platform_driver mpc52xx_uart_of_driver = {
      .owner            = THIS_MODULE,
      .name       = "mpc52xx-psc-uart",
      .match_table      = mpc52xx_uart_of_match,
      .probe            = mpc52xx_uart_of_probe,
      .remove           = mpc52xx_uart_of_remove,
#ifdef CONFIG_PM
      .suspend    = mpc52xx_uart_of_suspend,
      .resume           = mpc52xx_uart_of_resume,
#endif
      .driver           = {
            .name = "mpc52xx-psc-uart",
      },
};
#endif /* defined(CONFIG_PPC_MERGE) */


/* ======================================================================== */
/* Module                                                                   */
/* ======================================================================== */

static int __init
mpc52xx_uart_init(void)
{
      int ret;

      printk(KERN_INFO "Serial: MPC52xx PSC UART driver\n");

      if ((ret = uart_register_driver(&mpc52xx_uart_driver)) != 0) {
            printk(KERN_ERR "%s: uart_register_driver failed (%i)\n",
                   __FILE__, ret);
            return ret;
      }

#if defined(CONFIG_PPC_MERGE)
      mpc52xx_uart_of_enumerate();

      ret = of_register_platform_driver(&mpc52xx_uart_of_driver);
      if (ret) {
            printk(KERN_ERR "%s: of_register_platform_driver failed (%i)\n",
                   __FILE__, ret);
            uart_unregister_driver(&mpc52xx_uart_driver);
            return ret;
      }
#else
      ret = platform_driver_register(&mpc52xx_uart_platform_driver);
      if (ret) {
            printk(KERN_ERR "%s: platform_driver_register failed (%i)\n",
                   __FILE__, ret);
            uart_unregister_driver(&mpc52xx_uart_driver);
            return ret;
      }
#endif

      return 0;
}

static void __exit
mpc52xx_uart_exit(void)
{
#if defined(CONFIG_PPC_MERGE)
      of_unregister_platform_driver(&mpc52xx_uart_of_driver);
#else
      platform_driver_unregister(&mpc52xx_uart_platform_driver);
#endif
      uart_unregister_driver(&mpc52xx_uart_driver);
}


module_init(mpc52xx_uart_init);
module_exit(mpc52xx_uart_exit);

MODULE_AUTHOR("Sylvain Munaut <tnt@246tNt.com>");
MODULE_DESCRIPTION("Freescale MPC52xx PSC UART");
MODULE_LICENSE("GPL");

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