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early_printk.c

/*
 * arch/sh/kernel/early_printk.c
 *
 *  Copyright (C) 1999, 2000  Niibe Yutaka
 *  Copyright (C) 2002  M. R. Brown
 *  Copyright (C) 2004 - 2007  Paul Mundt
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */
#include <linux/console.h>
#include <linux/tty.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/delay.h>

#ifdef CONFIG_SH_STANDARD_BIOS
#include <asm/sh_bios.h>

/*
 *    Print a string through the BIOS
 */
static void sh_console_write(struct console *co, const char *s,
                         unsigned count)
{
      sh_bios_console_write(s, count);
}

/*
 *    Setup initial baud/bits/parity. We do two things here:
 *    - construct a cflag setting for the first rs_open()
 *    - initialize the serial port
 *    Return non-zero if we didn't find a serial port.
 */
static int __init sh_console_setup(struct console *co, char *options)
{
      int   cflag = CREAD | HUPCL | CLOCAL;

      /*
       *    Now construct a cflag setting.
       *    TODO: this is a totally bogus cflag, as we have
       *    no idea what serial settings the BIOS is using, or
       *    even if its using the serial port at all.
       */
      cflag |= B115200 | CS8 | /*no parity*/0;

      co->cflag = cflag;

      return 0;
}

static struct console bios_console = {
      .name       = "bios",
      .write            = sh_console_write,
      .setup            = sh_console_setup,
      .flags            = CON_PRINTBUFFER,
      .index            = -1,
};
#endif

#ifdef CONFIG_EARLY_SCIF_CONSOLE
#include <linux/serial_core.h>
#include "../../../drivers/serial/sh-sci.h"

#if defined(CONFIG_CPU_SUBTYPE_SH7720) || \
    defined(CONFIG_CPU_SUBTYPE_SH7721)
#define EPK_SCSMR_VALUE 0x000
#define EPK_SCBRR_VALUE 0x00C
#define EPK_FIFO_SIZE 64
#define EPK_FIFO_BITS (0x7f00 >> 8)
#else
#define EPK_FIFO_SIZE 16
#define EPK_FIFO_BITS (0x1f00 >> 8)
#endif

static struct uart_port scif_port = {
      .mapbase    = CONFIG_EARLY_SCIF_CONSOLE_PORT,
      .membase    = (char __iomem *)CONFIG_EARLY_SCIF_CONSOLE_PORT,
};

static void scif_sercon_putc(int c)
{
      while (((sci_in(&scif_port, SCFDR) & EPK_FIFO_BITS) >= EPK_FIFO_SIZE))
            ;

      sci_out(&scif_port, SCxTDR, c);
      sci_in(&scif_port, SCxSR);
      sci_out(&scif_port, SCxSR, 0xf3 & ~(0x20 | 0x40));

      while ((sci_in(&scif_port, SCxSR) & 0x40) == 0)
            ;

      if (c == '\n')
            scif_sercon_putc('\r');
}

static void scif_sercon_write(struct console *con, const char *s,
                        unsigned count)
{
      while (count-- > 0)
            scif_sercon_putc(*s++);
}

static int __init scif_sercon_setup(struct console *con, char *options)
{
      con->cflag = CREAD | HUPCL | CLOCAL | B115200 | CS8;

      return 0;
}

static struct console scif_console = {
      .name       = "sercon",
      .write            = scif_sercon_write,
      .setup            = scif_sercon_setup,
      .flags            = CON_PRINTBUFFER,
      .index            = -1,
};

#if !defined(CONFIG_SH_STANDARD_BIOS)
#if defined(CONFIG_CPU_SUBTYPE_SH7720) || \
    defined(CONFIG_CPU_SUBTYPE_SH7721)
static void scif_sercon_init(char *s)
{
      sci_out(&scif_port, SCSCR, 0x0000); /* clear TE and RE */
      sci_out(&scif_port, SCFCR, 0x4006); /* reset */
      sci_out(&scif_port, SCSCR, 0x0000); /* select internal clock */
      sci_out(&scif_port, SCSMR, EPK_SCSMR_VALUE);
      sci_out(&scif_port, SCBRR, EPK_SCBRR_VALUE);

      mdelay(1);  /* wait 1-bit time */

      sci_out(&scif_port, SCFCR, 0x0030); /* TTRG=b'11 */
      sci_out(&scif_port, SCSCR, 0x0030); /* TE, RE */
}
#elif defined(CONFIG_CPU_SH4)
#define DEFAULT_BAUD 115200
/*
 * Simple SCIF init, primarily aimed at SH7750 and other similar SH-4
 * devices that aren't using sh-ipl+g.
 */
static void scif_sercon_init(char *s)
{
      struct uart_port *port = &scif_port;
      unsigned baud = DEFAULT_BAUD;
      unsigned int status;
      char *e;

      if (*s == ',')
            ++s;

      if (*s) {
            /* ignore ioport/device name */
            s += strcspn(s, ",");
            if (*s == ',')
                  s++;
      }

      if (*s) {
            baud = simple_strtoul(s, &e, 0);
            if (baud == 0 || s == e)
                  baud = DEFAULT_BAUD;
      }

      do {
            status = sci_in(port, SCxSR);
      } while (!(status & SCxSR_TEND(port)));

      sci_out(port, SCSCR, 0);       /* TE=0, RE=0 */
      sci_out(port, SCFCR, SCFCR_RFRST | SCFCR_TFRST);
      sci_out(port, SCSMR, 0);

      /* Set baud rate */
      sci_out(port, SCBRR, (CONFIG_SH_PCLK_FREQ + 16 * baud) /
            (32 * baud) - 1);
      udelay((1000000+(baud-1)) / baud); /* Wait one bit interval */

      sci_out(port, SCSPTR, 0);
      sci_out(port, SCxSR, 0x60);
      sci_out(port, SCLSR, 0);

      sci_out(port, SCFCR, 0);
      sci_out(port, SCSCR, 0x30);    /* TE=1, RE=1 */
}
#endif /* defined(CONFIG_CPU_SUBTYPE_SH7720) */
#endif /* !defined(CONFIG_SH_STANDARD_BIOS) */
#endif /* CONFIG_EARLY_SCIF_CONSOLE */

/*
 * Setup a default console, if more than one is compiled in, rely on the
 * earlyprintk= parsing to give priority.
 */
static struct console *early_console =
#ifdef CONFIG_SH_STANDARD_BIOS
      &bios_console
#elif defined(CONFIG_EARLY_SCIF_CONSOLE)
      &scif_console
#else
      NULL
#endif
      ;

static int __init setup_early_printk(char *buf)
{
      int keep_early = 0;

      if (!buf)
            return 0;

      if (strstr(buf, "keep"))
            keep_early = 1;

#ifdef CONFIG_SH_STANDARD_BIOS
      if (!strncmp(buf, "bios", 4))
            early_console = &bios_console;
#endif
#if defined(CONFIG_EARLY_SCIF_CONSOLE)
      if (!strncmp(buf, "serial", 6)) {
            early_console = &scif_console;

#if !defined(CONFIG_SH_STANDARD_BIOS)
#if defined(CONFIG_CPU_SH4) || defined(CONFIG_CPU_SUBTYPE_SH7720) || \
    defined(CONFIG_CPU_SUBTYPE_SH7721)
            scif_sercon_init(buf + 6);
#endif
#endif
      }
#endif

      if (likely(early_console)) {
            if (keep_early)
                  early_console->flags &= ~CON_BOOT;
            else
                  early_console->flags |= CON_BOOT;
            register_console(early_console);
      }

      return 0;
}
early_param("earlyprintk", setup_early_printk);

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