/*
   Copyright (C) 2021 Free Software Foundation, Inc.

   This file is part of the GNU Hurd.

   The GNU Hurd 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, or (at
   your option) any later version.

   The GNU Hurd 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 the GNU Hurd.  If not, see <http://www.gnu.org/licenses/>.
*/

/* Implementation of ACPI operations */

#include <acpi_S.h>

#include <stdio.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/io.h>

#include "libacpica/acpi_init.h"
#include "acpifs.h"

static error_t
check_permissions (struct protid *master, int flags)
{
  struct node *node;
  struct acpifs_dirent *e;

  node = master->po->np;
  e = node->nn->ln;

  /* Check whether the user has permissions to access this node */
  return entry_check_perms (master->user, e, flags);
}

static void
acpi_enable(struct acpi_table *facp)
{
  int i;
  uint8_t *ptr = (uint8_t *)&facp->data;
  
  /* Grab value to write to SMI_CMD to enable ACPI */
  uint8_t acpi_en = ptr[SMI_EN_OFFSET];
  uint16_t smi_cmd = (uint16_t)ptr[SMI_CMD_OFFSET] | ((uint16_t)ptr[SMI_CMD_OFFSET+1] << 8);
  uint16_t pm1a_ctl = (uint16_t)ptr[PM1A_CTL_OFFSET] | ((uint16_t)ptr[PM1A_CTL_OFFSET+1] << 8);

  /* Get I/O permissions */
  if (ioperm(smi_cmd, 2, 1))
    {
      fprintf(stderr, "EPERM on ioperm(smi_cmd)\n");
      return;
    }

  if (ioperm(pm1a_ctl, 2, 1))
    {
      fprintf(stderr, "EPERM on ioperm(pm1a_ctl)\n");
      return;
    }

  /* Enable ACPI */
  outb(acpi_en, smi_cmd);
  for (i = 0; i < 300; i++)
    {
      if ((inw(pm1a_ctl) & SCI_EN) == SCI_EN)
        break;
    }

  /* Drop I/O permissions */
  ioperm(smi_cmd, 2, 0);
  ioperm(pm1a_ctl, 2, 0);
}

error_t
S_acpi_sleep (struct protid *master, int sleep_state)
{
  error_t err;
  struct acpifs_dirent *e;

  if (!master)
    return EOPNOTSUPP;

  e = master->po->np->nn->ln;
  if (strncmp (e->name, "FACP", 4))
    /* This operation may only be addressed to the FADT table */
    return EINVAL;

  err = check_permissions (master, O_READ);
  if (err)
    return err;

  /* Enable ACPI */
  acpi_enable(e->acpitable);

  /* Perform sleep */
  acpi_enter_sleep(sleep_state);

  /* Never reached */
  return err;
}

error_t
S_acpi_enable (struct protid *master)
{
  error_t err;
  struct acpifs_dirent *e;

  if (!master)
    return EOPNOTSUPP;

  e = master->po->np->nn->ln;
  if (strncmp (e->name, "FACP", 4))
    /* This operation may only be addressed to the FADT table */
    return EINVAL;

  err = check_permissions (master, O_READ);
  if (err)
    return err;

  acpi_enable(e->acpitable);
  return err;
}

error_t
S_acpi_get_irq (struct protid *master, int bus, int dev, int func, int *irq)
{
  error_t err;

  if (!master)
    return EOPNOTSUPP;

  err = check_permissions (master, O_READ);
  if (err)
    return err;

  *irq = acpi_get_irq_number(bus, dev, func);
  return err;
}