/*
 *  GRUB  --  GRand Unified Bootloader
 *  Copyright (C) 2007, 2008, 2009, 2010  Free Software Foundation, Inc.
 *
 *  GRUB 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 3 of the License, or
 *  (at your option) any later version.
 *
 *  GRUB 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 GRUB.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <grub/dl.h>
#include <grub/disk.h>
#include <grub/mm.h>
#include <grub/time.h>
#include <grub/pci.h>
#include <grub/ata.h>
#include <grub/scsi.h>
#include <grub/misc.h>
#include <grub/list.h>
#include <grub/loader.h>

GRUB_MOD_LICENSE ("GPLv3+");

struct grub_ahci_cmd_head
{
  grub_uint32_t config;
  grub_uint32_t transfered;
  grub_uint64_t command_table_base;
  grub_uint32_t unused[4];
};

struct grub_ahci_prdt_entry
{
  grub_uint64_t data_base;
  grub_uint32_t unused;
  grub_uint32_t size;
};

struct grub_ahci_cmd_table
{
  grub_uint8_t cfis[0x40];
  grub_uint8_t command[0x10];
  grub_uint8_t reserved[0x30];
  struct grub_ahci_prdt_entry prdt[1];
};

struct grub_ahci_hba_port
{
  grub_uint64_t command_list_base;
  grub_uint64_t fis_base;
  grub_uint32_t intstatus;
  grub_uint32_t inten;
  grub_uint32_t command;
  grub_uint32_t unused1;
  grub_uint32_t task_file_data;
  grub_uint32_t sig;
  grub_uint32_t status;
  grub_uint32_t unused2;
  grub_uint32_t sata_error;
  grub_uint32_t sata_active;
  grub_uint32_t command_issue;
  grub_uint32_t unused3;
  grub_uint32_t fbs;
  grub_uint32_t unused4[15];
};

enum grub_ahci_hba_port_command
  {
    GRUB_AHCI_HBA_PORT_CMD_ST  = 0x01,
    GRUB_AHCI_HBA_PORT_CMD_FRE = 0x10,
    GRUB_AHCI_HBA_PORT_CMD_CR = 0x8000,
    GRUB_AHCI_HBA_PORT_CMD_FR = 0x4000,
  };

struct grub_ahci_hba
{
  grub_uint32_t cap;
  grub_uint32_t global_control;
  grub_uint32_t intr_status;
  grub_uint32_t ports_implemented;
  grub_uint32_t unused1[6];
  grub_uint32_t bios_handoff;
  grub_uint32_t unused2[53];
  struct grub_ahci_hba_port ports[32];
};

struct grub_ahci_received_fis
{
  char raw[4096];
};

enum
  {
    GRUB_AHCI_HBA_CAP_NPORTS_MASK = 0x1f
  };

enum
  {
    GRUB_AHCI_HBA_GLOBAL_CONTROL_RESET = 0x00000001,
    GRUB_AHCI_HBA_GLOBAL_CONTROL_INTR_EN = 0x00000002,
    GRUB_AHCI_HBA_GLOBAL_CONTROL_AHCI_EN = 0x80000000,
  };

enum
  {
    GRUB_AHCI_BIOS_HANDOFF_BIOS_OWNED = 1,
    GRUB_AHCI_BIOS_HANDOFF_OS_OWNED = 2,
    GRUB_AHCI_BIOS_HANDOFF_OS_OWNERSHIP_CHANGED = 8,
    GRUB_AHCI_BIOS_HANDOFF_RWC = 8
  };


struct grub_ahci_device
{
  struct grub_ahci_device *next;
  struct grub_ahci_device **prev;
  volatile struct grub_ahci_hba *hba;
  int port;
  int num;
  struct grub_pci_dma_chunk *command_list_chunk;
  volatile struct grub_ahci_cmd_head *command_list;
  struct grub_pci_dma_chunk *command_table_chunk;
  volatile struct grub_ahci_cmd_table *command_table;
  struct grub_pci_dma_chunk *rfis;
  int present;
};

static grub_err_t 
grub_ahci_readwrite_real (struct grub_ahci_device *dev,
			  struct grub_disk_ata_pass_through_parms *parms,
			  int spinup);


enum
  {
    GRUB_AHCI_CONFIG_READ = 0,
    GRUB_AHCI_CONFIG_CFIS_LENGTH_MASK = 0x1f,
    GRUB_AHCI_CONFIG_ATAPI = 0x20,
    GRUB_AHCI_CONFIG_WRITE = 0x40,
    GRUB_AHCI_CONFIG_PREFETCH = 0x80,
    GRUB_AHCI_CONFIG_RESET = 0x100,
    GRUB_AHCI_CONFIG_BIST = 0x200,
    GRUB_AHCI_CONFIG_CLEAR_R_OK = 0x400,
    GRUB_AHCI_CONFIG_PMP_MASK = 0xf000,
    GRUB_AHCI_CONFIG_PRDT_LENGTH_MASK = 0xffff0000,
  };
#define GRUB_AHCI_CONFIG_CFIS_LENGTH_SHIFT 0
#define GRUB_AHCI_CONFIG_PMP_SHIFT 12
#define GRUB_AHCI_CONFIG_PRDT_LENGTH_SHIFT 16
#define GRUB_AHCI_INTERRUPT_ON_COMPLETE 0x80000000

#define GRUB_AHCI_PRDT_MAX_CHUNK_LENGTH 0x200000

static struct grub_ahci_device *grub_ahci_devices;
static int numdevs;

static int 
init_port (struct grub_ahci_device *dev)
{
  struct grub_pci_dma_chunk *command_list;
  struct grub_pci_dma_chunk *command_table;
  grub_uint64_t endtime;

  command_list = grub_memalign_dma32 (1024, sizeof (struct grub_ahci_cmd_head));
  if (!command_list)
    return 1;

  command_table = grub_memalign_dma32 (1024,
				       sizeof (struct grub_ahci_cmd_table));
  if (!command_table)
    {
      grub_dma_free (command_list);
      return 1;
    }

  grub_dprintf ("ahci", "found device ahci%d (port %d)\n", dev->num, dev->port);

  dev->hba->ports[dev->port].command &= ~GRUB_AHCI_HBA_PORT_CMD_FRE;
  endtime = grub_get_time_ms () + 1000;
  while ((dev->hba->ports[dev->port].command & GRUB_AHCI_HBA_PORT_CMD_FR))
    if (grub_get_time_ms () > endtime)
      {
	grub_dprintf ("ahci", "couldn't stop FR\n");
	goto out;
      }

  dev->hba->ports[dev->port].command &= ~GRUB_AHCI_HBA_PORT_CMD_ST;
  endtime = grub_get_time_ms () + 1000;
  while ((dev->hba->ports[dev->port].command & GRUB_AHCI_HBA_PORT_CMD_CR))
    if (grub_get_time_ms () > endtime)
      {
	grub_dprintf ("ahci", "couldn't stop CR\n");
	goto out;
      }

  dev->hba->ports[dev->port].fbs = 2;

  dev->rfis = grub_memalign_dma32 (4096, 
				   sizeof (struct grub_ahci_received_fis));
  grub_memset ((char *) grub_dma_get_virt (dev->rfis), 0,
	       sizeof (struct grub_ahci_received_fis));
  dev->hba->ports[dev->port].fis_base = grub_dma_get_phys (dev->rfis);
  dev->hba->ports[dev->port].command_list_base
    = grub_dma_get_phys (command_list);
  dev->hba->ports[dev->port].command |= GRUB_AHCI_HBA_PORT_CMD_FRE;
  while (!(dev->hba->ports[dev->port].command & GRUB_AHCI_HBA_PORT_CMD_FR))
    if (grub_get_time_ms () > endtime)
      {
	grub_dprintf ("ahci", "couldn't start FR\n");
	dev->hba->ports[dev->port].command &= ~GRUB_AHCI_HBA_PORT_CMD_FRE;
	goto out;
      }
  dev->hba->ports[dev->port].command |= GRUB_AHCI_HBA_PORT_CMD_ST;
  while (!(dev->hba->ports[dev->port].command & GRUB_AHCI_HBA_PORT_CMD_CR))
    if (grub_get_time_ms () > endtime)
      {
	grub_dprintf ("ahci", "couldn't start CR\n");
	dev->hba->ports[dev->port].command &= ~GRUB_AHCI_HBA_PORT_CMD_CR;
	goto out_stop_fr;
      }

  dev->hba->ports[dev->port].command
    = (dev->hba->ports[dev->port].command & 0x0fffffff) | (1 << 28) | 2 | 4;

  dev->command_list_chunk = command_list;
  dev->command_list = grub_dma_get_virt (command_list);
  dev->command_table_chunk = command_table;
  dev->command_table = grub_dma_get_virt (command_table);
  dev->command_list->command_table_base
    = grub_dma_get_phys (command_table);

  return 0;
 out_stop_fr:
  dev->hba->ports[dev->port].command &= ~GRUB_AHCI_HBA_PORT_CMD_FRE;
  endtime = grub_get_time_ms () + 1000;
  while ((dev->hba->ports[dev->port].command & GRUB_AHCI_HBA_PORT_CMD_FR))
    if (grub_get_time_ms () > endtime)
      {
	grub_dprintf ("ahci", "couldn't stop FR\n");
	break;
      }
 out:
  grub_dma_free (command_list);
  grub_dma_free (command_table);
  grub_dma_free (dev->rfis);
  return 1;
}

static int NESTED_FUNC_ATTR
grub_ahci_pciinit (grub_pci_device_t dev,
		   grub_pci_id_t pciid __attribute__ ((unused)))
{
  grub_pci_address_t addr;
  grub_uint32_t class;
  grub_uint32_t bar;
  unsigned i, nports;
  volatile struct grub_ahci_hba *hba;

  /* Read class.  */
  addr = grub_pci_make_address (dev, GRUB_PCI_REG_CLASS);
  class = grub_pci_read (addr);

  /* Check if this class ID matches that of a PCI IDE Controller.  */
  if (class >> 8 != 0x010601)
    return 0;

  addr = grub_pci_make_address (dev, GRUB_PCI_REG_ADDRESS_REG5);
  bar = grub_pci_read (addr);

  if ((bar & (GRUB_PCI_ADDR_SPACE_MASK | GRUB_PCI_ADDR_MEM_TYPE_MASK
	      | GRUB_PCI_ADDR_MEM_PREFETCH))
      != (GRUB_PCI_ADDR_SPACE_MEMORY | GRUB_PCI_ADDR_MEM_TYPE_32))
    return 0;

  hba = grub_pci_device_map_range (dev, bar & GRUB_PCI_ADDR_MEM_MASK,
				   sizeof (hba));

  if (! (hba->bios_handoff & GRUB_AHCI_BIOS_HANDOFF_OS_OWNED))
    {
      grub_uint64_t endtime;

      grub_dprintf ("ahci", "Requesting AHCI ownership\n");
      hba->bios_handoff = (hba->bios_handoff & ~GRUB_AHCI_BIOS_HANDOFF_RWC)
	| GRUB_AHCI_BIOS_HANDOFF_OS_OWNED;
      grub_dprintf ("ahci", "Waiting for BIOS to give up ownership\n");
      endtime = grub_get_time_ms () + 1000;
      while ((hba->bios_handoff & GRUB_AHCI_BIOS_HANDOFF_BIOS_OWNED)
	     && grub_get_time_ms () < endtime);
      if (hba->bios_handoff & GRUB_AHCI_BIOS_HANDOFF_BIOS_OWNED)
	{
	  grub_dprintf ("ahci", "Forcibly taking ownership\n");
	  hba->bios_handoff = GRUB_AHCI_BIOS_HANDOFF_OS_OWNED;
	  hba->bios_handoff |= GRUB_AHCI_BIOS_HANDOFF_OS_OWNERSHIP_CHANGED;
	}
      else
	grub_dprintf ("ahci", "AHCI ownership obtained\n");
    }
  else
    grub_dprintf ("ahci", "AHCI is already in OS mode\n");

  if (!(hba->global_control & GRUB_AHCI_HBA_GLOBAL_CONTROL_AHCI_EN))
    grub_dprintf ("ahci", "AHCI is in compat mode. Switching\n");
  else
    grub_dprintf ("ahci", "AHCI is in AHCI mode.\n");

  for (i = 0; i < 5; i++)
    {
      hba->global_control |= GRUB_AHCI_HBA_GLOBAL_CONTROL_AHCI_EN;
      grub_millisleep (1);
      if (hba->global_control & GRUB_AHCI_HBA_GLOBAL_CONTROL_AHCI_EN)
	break;
    }
  if (i == 5)
    {
      grub_dprintf ("ahci", "Couldn't put AHCI in AHCI mode\n");
      return 0;
    }

  /*
  {
      grub_uint64_t endtime;
      hba->global_control |= 1;
      endtime = grub_get_time_ms () + 1000;
      while (hba->global_control & 1)
	if (grub_get_time_ms () > endtime)
	  {
	    grub_dprintf ("ahci", "couldn't reset AHCI\n");
	    return 0;
	  }
  }

  for (i = 0; i < 5; i++)
    {
      hba->global_control |= GRUB_AHCI_HBA_GLOBAL_CONTROL_AHCI_EN;
      grub_millisleep (1);
      if (hba->global_control & GRUB_AHCI_HBA_GLOBAL_CONTROL_AHCI_EN)
	break;
    }
  if (i == 5)
    {
      grub_dprintf ("ahci", "Couldn't put AHCI in AHCI mode\n");
      return 0;
    }
  */

  nports = (hba->cap & GRUB_AHCI_HBA_CAP_NPORTS_MASK) + 1;

  grub_dprintf ("ahci", "%d AHCI ports\n", nports);

  for (i = 0; i < nports; i++)
    {
      struct grub_ahci_device *adev;
      grub_uint32_t st;

      if (!(hba->ports_implemented & (1 << i)))
	continue;

      grub_dprintf ("ahci", "status %d:%x\n", i, hba->ports[i].status);
      /* FIXME: support hotplugging.  */
      st = hba->ports[i].status;
      if ((st & 0xf) != 0x3 && (st & 0xf) != 0x1)
	continue;

      adev = grub_malloc (sizeof (*adev));
      if (!adev)
	return 1;

      adev->hba = hba;
      adev->port = i;
      adev->present = 1;
      adev->num = numdevs++;

      if (init_port (adev))
	{
	  grub_free (adev);
	  return 1;
	}

      grub_list_push (GRUB_AS_LIST_P (&grub_ahci_devices),
		      GRUB_AS_LIST (adev));
    }

  return 0;
}

static grub_err_t
grub_ahci_initialize (void)
{
  grub_pci_iterate (grub_ahci_pciinit);
  return grub_errno;
}

static grub_err_t
grub_ahci_fini_hw (int noreturn __attribute__ ((unused)))
{
  struct grub_ahci_device *dev;

  for (dev = grub_ahci_devices; dev; dev = dev->next)
    {
      grub_uint64_t endtime;

      dev->hba->ports[dev->port].command &= ~GRUB_AHCI_HBA_PORT_CMD_FRE;
      endtime = grub_get_time_ms () + 1000;
      while ((dev->hba->ports[dev->port].command & GRUB_AHCI_HBA_PORT_CMD_FR))
	if (grub_get_time_ms () > endtime)
	  {
	    grub_dprintf ("ahci", "couldn't stop FR\n");
	    break;
	  }

      dev->hba->ports[dev->port].command &= ~GRUB_AHCI_HBA_PORT_CMD_ST;
      endtime = grub_get_time_ms () + 1000;
      while ((dev->hba->ports[dev->port].command & GRUB_AHCI_HBA_PORT_CMD_CR))
	if (grub_get_time_ms () > endtime)
	  {
	    grub_dprintf ("ahci", "couldn't stop CR\n");
	    break;
	  }
      grub_dma_free (dev->command_list_chunk);
      grub_dma_free (dev->command_table_chunk);
      grub_dma_free (dev->rfis);
      dev->command_list_chunk = NULL;
      dev->command_table_chunk = NULL;
      dev->rfis = NULL;
    }
  return GRUB_ERR_NONE;
}

static grub_err_t
grub_ahci_restore_hw (void)
{
  struct grub_ahci_device **pdev;

  for (pdev = &grub_ahci_devices; *pdev; pdev = &((*pdev)->next))
    if (init_port (*pdev))
      {
	struct grub_ahci_device *odev;
	odev = *pdev;
	*pdev = (*pdev)->next;
	grub_free (odev);
      }
  return GRUB_ERR_NONE;
}




static int
grub_ahci_iterate (int (*hook) (int id, int bus),
		  grub_disk_pull_t pull)
{
  struct grub_ahci_device *dev;

  if (pull != GRUB_DISK_PULL_NONE)
    return 0;

  FOR_LIST_ELEMENTS(dev, grub_ahci_devices)
    if (hook (GRUB_SCSI_SUBSYSTEM_AHCI, dev->num))
      return 1;

  return 0;
}

#if 0
static int
find_free_cmd_slot (struct grub_ahci_device *dev)
{
  int i;
  for (i = 0; i < 32; i++)
    {
      if (dev->hda->ports[dev->port].command_issue & (1 << i))
	continue;
      if (dev->hda->ports[dev->port].sata_active & (1 << i))
	continue;
      return i;
    }
  return -1;
}
#endif

enum
  {
    GRUB_AHCI_FIS_REG_H2D = 0x27
  };

static const int register_map[11] = { 3 /* Features */,
				      12 /* Sectors */,
				      4 /* LBA low */,
				      5 /* LBA mid */,
				      6 /* LBA high */,
				      7 /* Device */,
				      2 /* CMD register */,
				      13 /* Sectors 48  */,
				      8 /* LBA48 low */,
				      9 /* LBA48 mid */,
				      10 /* LBA48 high */ }; 

static grub_err_t 
grub_ahci_readwrite_real (struct grub_ahci_device *dev,
			  struct grub_disk_ata_pass_through_parms *parms,
			  int spinup)
{
  struct grub_pci_dma_chunk *bufc;
  grub_uint64_t endtime;
  unsigned i;
  grub_err_t err = GRUB_ERR_NONE;

  grub_dprintf ("ahci", "AHCI tfd = %x\n",
		dev->hba->ports[dev->port].task_file_data);

  if ((dev->hba->ports[dev->port].task_file_data & 0x80))
    {
      dev->hba->ports[dev->port].command &= ~GRUB_AHCI_HBA_PORT_CMD_ST;
      endtime = grub_get_time_ms () + 1000;
      while ((dev->hba->ports[dev->port].command & GRUB_AHCI_HBA_PORT_CMD_CR))
	if (grub_get_time_ms () > endtime)
	  {
	    grub_dprintf ("ahci", "couldn't stop CR\n");
	    break;
	  }
      dev->hba->ports[dev->port].command |= GRUB_AHCI_HBA_PORT_CMD_ST;
      endtime = grub_get_time_ms () + (spinup ? 10000 : 1000);
      while (!(dev->hba->ports[dev->port].command & GRUB_AHCI_HBA_PORT_CMD_CR))
	if (grub_get_time_ms () > endtime)
	  {
	    grub_dprintf ("ahci", "couldn't start CR\n");
	    break;
	  }
    }

  dev->hba->ports[dev->port].sata_error = dev->hba->ports[dev->port].sata_error;

  grub_dprintf("ahci", "grub_ahci_read (size=%llu, cmdsize = %llu)\n",
	       (unsigned long long) parms->size,
	       (unsigned long long) parms->cmdsize);

  if (parms->cmdsize != 0 && parms->cmdsize != 12 && parms->cmdsize != 16)
    return grub_error (GRUB_ERR_BUG, "incorrect ATAPI command size");

  if (parms->size > GRUB_AHCI_PRDT_MAX_CHUNK_LENGTH)
    return grub_error (GRUB_ERR_BUG, "too big data buffer");

  bufc = grub_memalign_dma32 (1024, parms->size + (parms->size & 1));

  dev->hba->ports[dev->port].command |= 8;

  grub_dprintf ("ahci", "AHCI tfd = %x\n",
		dev->hba->ports[dev->port].task_file_data);
  /* FIXME: support port multipliers.  */
  dev->command_list[0].config
    = (5 << GRUB_AHCI_CONFIG_CFIS_LENGTH_SHIFT)
    //    | GRUB_AHCI_CONFIG_CLEAR_R_OK
    | (0 << GRUB_AHCI_CONFIG_PMP_SHIFT)
    | (1 << GRUB_AHCI_CONFIG_PRDT_LENGTH_SHIFT)
    | (parms->cmdsize ? GRUB_AHCI_CONFIG_ATAPI : 0)
    | (parms->write ? GRUB_AHCI_CONFIG_WRITE : GRUB_AHCI_CONFIG_READ)
    | (parms->taskfile.cmd == 8 ? (1 << 8) : 0);
  dev->command_list[0].transfered = 0;
  dev->command_list[0].command_table_base
    = grub_dma_get_phys (dev->command_table_chunk);
  grub_memset ((char *) dev->command_list[0].unused, 0,
	       sizeof (dev->command_list[0].unused));
  grub_memset ((char *) &dev->command_table[0], 0,
	       sizeof (dev->command_table[0]));
  if (parms->cmdsize)
    grub_memcpy ((char *) dev->command_table[0].command, parms->cmd,
		 parms->cmdsize);

  dev->command_table[0].cfis[0] = GRUB_AHCI_FIS_REG_H2D;
  dev->command_table[0].cfis[1] = 0x80;
  for (i = 0; i < sizeof (parms->taskfile.raw); i++)
    dev->command_table[0].cfis[register_map[i]] = parms->taskfile.raw[i]; 

  grub_dprintf ("ahci", "cfis: %02x %02x %02x %02x %02x %02x %02x %02x\n",
		dev->command_table[0].cfis[0], dev->command_table[0].cfis[1],
		dev->command_table[0].cfis[2], dev->command_table[0].cfis[3],
		dev->command_table[0].cfis[4], dev->command_table[0].cfis[5],
		dev->command_table[0].cfis[6], dev->command_table[0].cfis[7]);
  grub_dprintf ("ahci", "cfis: %02x %02x %02x %02x %02x %02x %02x %02x\n",
		dev->command_table[0].cfis[8], dev->command_table[0].cfis[9],
		dev->command_table[0].cfis[10], dev->command_table[0].cfis[11],
		dev->command_table[0].cfis[12], dev->command_table[0].cfis[13],
		dev->command_table[0].cfis[14], dev->command_table[0].cfis[15]);

  dev->command_table[0].prdt[0].data_base = grub_dma_get_phys (bufc);
  dev->command_table[0].prdt[0].unused = 0;
  dev->command_table[0].prdt[0].size = (parms->size + (parms->size & 1) - 1)
    | GRUB_AHCI_INTERRUPT_ON_COMPLETE;

  grub_dprintf ("ahci", "PRDT = %" PRIxGRUB_UINT64_T ", %x, %x (%"
		PRIuGRUB_SIZE ")\n",
		dev->command_table[0].prdt[0].data_base,
		dev->command_table[0].prdt[0].unused,
		dev->command_table[0].prdt[0].size,
		(char *) &dev->command_table[0].prdt[0]
		- (char *) &dev->command_table[0]);

  if (parms->write)
    grub_memcpy ((char *) grub_dma_get_virt (bufc), parms->buffer, parms->size);

  grub_dprintf ("ahci", "AHCI command schedulded\n");
  grub_dprintf ("ahci", "AHCI tfd = %x\n",
		dev->hba->ports[dev->port].task_file_data);
  dev->hba->ports[dev->port].inten = 0xffffffff;//(1 << 2) | (1 << 5);
  dev->hba->ports[dev->port].intstatus = 0xffffffff;//(1 << 2) | (1 << 5);
  grub_dprintf ("ahci", "AHCI tfd = %x\n",
		dev->hba->ports[dev->port].task_file_data);
  dev->hba->ports[dev->port].command_issue |= 1;
  grub_dprintf ("ahci", "AHCI sig = %x\n", dev->hba->ports[dev->port].sig);
  grub_dprintf ("ahci", "AHCI tfd = %x\n",
		dev->hba->ports[dev->port].task_file_data);

  endtime = grub_get_time_ms () + (spinup ? 10000 : 1000);
  while ((dev->hba->ports[dev->port].command_issue & 1))
    if (grub_get_time_ms () > endtime)
      {
	grub_dprintf ("ahci", "AHCI status <%x %x %x>\n",
		      dev->hba->ports[dev->port].command_issue,
		      dev->hba->ports[dev->port].intstatus,
		      dev->hba->ports[dev->port].task_file_data);
	err = grub_error (GRUB_ERR_IO, "AHCI transfer timed out");
	break;
      }

  grub_dprintf ("ahci", "AHCI command completed <%x %x %x %x %x, %x %x>\n",
		dev->hba->ports[dev->port].command_issue,
		dev->hba->ports[dev->port].intstatus,
		dev->hba->ports[dev->port].task_file_data,
		dev->command_list[0].transfered,
		dev->hba->ports[dev->port].sata_error,
		((grub_uint32_t *) grub_dma_get_virt (dev->rfis))[0x00],
		((grub_uint32_t *) grub_dma_get_virt (dev->rfis))[0x18]);
  grub_dprintf ("ahci",
		"last PIO FIS %08x %08x %08x %08x %08x %08x %08x %08x\n",
		((grub_uint32_t *) grub_dma_get_virt (dev->rfis))[0x08],
		((grub_uint32_t *) grub_dma_get_virt (dev->rfis))[0x09],
		((grub_uint32_t *) grub_dma_get_virt (dev->rfis))[0x0a],
		((grub_uint32_t *) grub_dma_get_virt (dev->rfis))[0x0b],
		((grub_uint32_t *) grub_dma_get_virt (dev->rfis))[0x0c],
		((grub_uint32_t *) grub_dma_get_virt (dev->rfis))[0x0d],
		((grub_uint32_t *) grub_dma_get_virt (dev->rfis))[0x0e],
		((grub_uint32_t *) grub_dma_get_virt (dev->rfis))[0x0f]);
  grub_dprintf ("ahci",
		"last REG FIS %08x %08x %08x %08x %08x %08x %08x %08x\n",
		((grub_uint32_t *) grub_dma_get_virt (dev->rfis))[0x10],
		((grub_uint32_t *) grub_dma_get_virt (dev->rfis))[0x11],
		((grub_uint32_t *) grub_dma_get_virt (dev->rfis))[0x12],
		((grub_uint32_t *) grub_dma_get_virt (dev->rfis))[0x13],
		((grub_uint32_t *) grub_dma_get_virt (dev->rfis))[0x14],
		((grub_uint32_t *) grub_dma_get_virt (dev->rfis))[0x15],
		((grub_uint32_t *) grub_dma_get_virt (dev->rfis))[0x16],
		((grub_uint32_t *) grub_dma_get_virt (dev->rfis))[0x17]);

  if (!parms->write)
    grub_memcpy (parms->buffer, (char *) grub_dma_get_virt (bufc), parms->size);
  grub_dma_free (bufc);

  return err;
}

static grub_err_t 
grub_ahci_readwrite (grub_ata_t disk,
		     struct grub_disk_ata_pass_through_parms *parms,
		     int spinup)
{
  return grub_ahci_readwrite_real (disk->data, parms, spinup);
}

static grub_err_t
grub_ahci_open (int id, int devnum, struct grub_ata *ata)
{
  struct grub_ahci_device *dev;

  if (id != GRUB_SCSI_SUBSYSTEM_AHCI)
    return grub_error (GRUB_ERR_UNKNOWN_DEVICE, "not an AHCI device");

  FOR_LIST_ELEMENTS(dev, grub_ahci_devices)
    if (dev->num == devnum)
      break;

  if (! dev)
    return grub_error (GRUB_ERR_UNKNOWN_DEVICE, "no such AHCI device");

  grub_dprintf ("ahci", "opening AHCI dev `ahci%d'\n", dev->num);

  ata->data = dev;
  ata->dma = 1;
  ata->maxbuffer = GRUB_AHCI_PRDT_MAX_CHUNK_LENGTH;
  ata->present = &dev->present;

  return GRUB_ERR_NONE;
}

static struct grub_ata_dev grub_ahci_dev =
  {
    .iterate = grub_ahci_iterate,
    .open = grub_ahci_open,
    .readwrite = grub_ahci_readwrite,
  };



static struct grub_preboot *fini_hnd;

GRUB_MOD_INIT(ahci)
{
  /* To prevent two drivers operating on the same disks.  */
  grub_disk_firmware_is_tainted = 1;
  if (grub_disk_firmware_fini)
    {
      grub_disk_firmware_fini ();
      grub_disk_firmware_fini = NULL;
    }

  /* AHCI initialization.  */
  grub_ahci_initialize ();

  /* AHCI devices are handled by scsi.mod.  */
  grub_ata_dev_register (&grub_ahci_dev);

  fini_hnd = grub_loader_register_preboot_hook (grub_ahci_fini_hw,
						grub_ahci_restore_hw,
						GRUB_LOADER_PREBOOT_HOOK_PRIO_DISK);
}

GRUB_MOD_FINI(ahci)
{
  grub_ahci_fini_hw (0);
  grub_loader_unregister_preboot_hook (fini_hnd);

  grub_ata_dev_unregister (&grub_ahci_dev);
}