src/superio/nsc/pc97317/early_serial.c

   1 /*
   2  * This file is part of the coreboot project.
   3  *
   4  * Copyright (C) 2000 AG Electronics Ltd.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  */
  16
  17 #include <arch/io.h>
  18 #include <device/pnp.h>
  19 #include <stdint.h>
  20 #include "pc97317.h"
  21
  22 #define PM_DEV PNP_DEV(0x2e, PC97317_PM)
  23 #define PM_BASE 0xe8
  24
  25 /* The PC97317 needs clocks to be set up before the serial port will operate. */
  26 void pc97317_enable_serial(pnp_devfn_t dev, u16 iobase)
  27 {
  28         /* Set base address of power management unit. */
  29         pnp_set_logical_device(PM_DEV);
  30         pnp_set_enable(dev, 0);
  31         pnp_set_iobase(dev, PNP_IDX_IO0, PM_BASE);
  32         pnp_set_enable(dev, 1);
  33
  34         /* Use on-chip clock multiplier. */
  35         outb(0x03, PM_BASE);
  36         outb(inb(PM_BASE + 1) | 0x07, PM_BASE + 1);
  37
  38         /* Wait for the clock to stabilise. */
  39         while(!(inb(PM_BASE + 1) & 0x80))
  40                 ;
  41
  42         /* Set the base address of the port. */
  43         pnp_set_logical_device(dev);
  44         pnp_set_enable(dev, 0);
  45         pnp_set_iobase(dev, PNP_IDX_IO0, iobase);
  46         pnp_set_enable(dev, 1);
  47 }