/*

   * New ATA layer SC1200 driver		Alan Cox <alan@lxorguk.ukuu.org.uk>

   *
   * TODO: Mode selection filtering

   * TODO: Needs custom DMA cleanup code
   *
   * Based very heavily on
   *
   * linux/drivers/ide/pci/sc1200.c		Version 0.91	28-Jan-2003
   *
   * Copyright (C) 2000-2002		Mark Lord <mlord@pobox.com>
   * May be copied or modified under the terms of the GNU General Public License
   *
   * Development of this chipset driver was funded
   * by the nice folks at National Semiconductor.
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   *
   * This program 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 this program; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

   *

   */
  
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/pci.h>
  #include <linux/init.h>
  #include <linux/blkdev.h>
  #include <linux/delay.h>
  #include <scsi/scsi_host.h>
  #include <linux/libata.h>

  #define DRV_NAME	"pata_sc1200"

  #define DRV_VERSION	"0.2.6"

  
  #define SC1200_REV_A	0x00
  #define SC1200_REV_B1	0x01
  #define SC1200_REV_B3	0x02
  #define SC1200_REV_C1	0x03
  #define SC1200_REV_D1	0x04
  
  /**
   *	sc1200_clock	-	PCI clock
   *
   *	Return the PCI bus clocking for the SC1200 chipset configuration
   *	in use. We return 0 for 33MHz 1 for 48MHz and 2 for 66Mhz
   */

  static int sc1200_clock(void)
  {
  	/* Magic registers that give us the chipset data */
  	u8 chip_id = inb(0x903C);
  	u8 silicon_rev = inb(0x903D);
  	u16 pci_clock;

  	if (chip_id == 0x04 && silicon_rev < SC1200_REV_B1)
  		return 0;	/* 33 MHz mode */
  
  	/* Clock generator configuration 0x901E its 8/9 are the PCI clocking
  	   0/3 is 33Mhz 1 is 48 2 is 66 */
  
  	pci_clock = inw(0x901E);
  	pci_clock >>= 8;
  	pci_clock &= 0x03;
  	if (pci_clock == 3)
  		pci_clock = 0;
  	return pci_clock;
  }
  
  /**
   *	sc1200_set_piomode		-	PIO setup
   *	@ap: ATA interface
   *	@adev: device on the interface
   *
   *	Set our PIO requirements. This is fairly simple on the SC1200
   */

  static void sc1200_set_piomode(struct ata_port *ap, struct ata_device *adev)
  {
  	static const u32 pio_timings[4][5] = {

  		/* format0, 33Mhz */
  		{ 0x00009172, 0x00012171, 0x00020080, 0x00032010, 0x00040010 },
  		/* format1, 33Mhz */
  		{ 0xd1329172, 0x71212171, 0x30200080, 0x20102010, 0x00100010 },
  		/* format1, 48Mhz */
  		{ 0xfaa3f4f3, 0xc23232b2, 0x513101c1, 0x31213121, 0x10211021 },
  		/* format1, 66Mhz */
  		{ 0xfff4fff4, 0xf35353d3, 0x814102f1, 0x42314231, 0x11311131 }

  	};
  
  	struct pci_dev *pdev = to_pci_dev(ap->host->dev);
  	u32 format;
  	unsigned int reg = 0x40 + 0x10 * ap->port_no;
  	int mode = adev->pio_mode - XFER_PIO_0;

  	pci_read_config_dword(pdev, reg + 4, &format);
  	format >>= 31;
  	format += sc1200_clock();

  	pci_write_config_dword(pdev, reg + 8 * adev->devno,

  				pio_timings[format][mode]);
  }
  
  /**
   *	sc1200_set_dmamode		-	DMA timing setup
   *	@ap: ATA interface
   *	@adev: Device being configured
   *
   *	We cannot mix MWDMA and UDMA without reloading timings each switch
   *	master to slave.
   */

  static void sc1200_set_dmamode(struct ata_port *ap, struct ata_device *adev)
  {
  	static const u32 udma_timing[3][3] = {
  		{ 0x00921250, 0x00911140, 0x00911030 },
  		{ 0x00932470, 0x00922260, 0x00922140 },
  		{ 0x009436A1, 0x00933481, 0x00923261 }
  	};

  	static const u32 mwdma_timing[3][3] = {
  		{ 0x00077771, 0x00012121, 0x00002020 },
  		{ 0x000BBBB2, 0x00024241, 0x00013131 },
  		{ 0x000FFFF3, 0x00035352, 0x00015151 }
  	};

  	int clock = sc1200_clock();
  	struct pci_dev *pdev = to_pci_dev(ap->host->dev);
  	unsigned int reg = 0x40 + 0x10 * ap->port_no;
  	int mode = adev->dma_mode;
  	u32 format;
  
  	if (mode >= XFER_UDMA_0)
  		format = udma_timing[clock][mode - XFER_UDMA_0];
  	else
  		format = mwdma_timing[clock][mode - XFER_MW_DMA_0];

  	if (adev->devno == 0) {
  		u32 timings;

  		pci_read_config_dword(pdev, reg + 4, &timings);
  		timings &= 0x80000000UL;
  		timings |= format;
  		pci_write_config_dword(pdev, reg + 4, timings);
  	} else
  		pci_write_config_dword(pdev, reg + 12, format);
  }
  
  /**

   *	sc1200_qc_issue		-	command issue

   *	@qc: command pending
   *
   *	Called when the libata layer is about to issue a command. We wrap
   *	this interface so that we can load the correct ATA timings if

   *	necessary.  Specifically we have a problem that there is only

   *	one MWDMA/UDMA bit.
   */

  static unsigned int sc1200_qc_issue(struct ata_queued_cmd *qc)

  {
  	struct ata_port *ap = qc->ap;
  	struct ata_device *adev = qc->dev;
  	struct ata_device *prev = ap->private_data;
  
  	/* See if the DMA settings could be wrong */

  	if (ata_dma_enabled(adev) && adev != prev && prev != NULL) {

  		/* Maybe, but do the channels match MWDMA/UDMA ? */

  		if ((ata_using_udma(adev) && !ata_using_udma(prev)) ||
  		    (ata_using_udma(prev) && !ata_using_udma(adev)))

  		    	/* Switch the mode bits */
  		    	sc1200_set_dmamode(ap, adev);
  	}

  	return ata_bmdma_qc_issue(qc);

  }

  /**
   *	sc1200_qc_defer	-	implement serialization
   *	@qc: command
   *
   *	Serialize command issue on this controller.
   */
  
  static int sc1200_qc_defer(struct ata_queued_cmd *qc)
  {
  	struct ata_host *host = qc->ap->host;
  	struct ata_port *alt = host->ports[1 ^ qc->ap->port_no];
  	int rc;
  
  	/* First apply the usual rules */
  	rc = ata_std_qc_defer(qc);
  	if (rc != 0)
  		return rc;
  
  	/* Now apply serialization rules. Only allow a command if the
  	   other channel state machine is idle */
  	if (alt && alt->qc_active)
  		return	ATA_DEFER_PORT;
  	return 0;
  }

  static struct scsi_host_template sc1200_sht = {

  	ATA_BMDMA_SHT(DRV_NAME),
  	.sg_tablesize	= LIBATA_DUMB_MAX_PRD,

  };
  
  static struct ata_port_operations sc1200_port_ops = {

  	.inherits	= &ata_bmdma_port_ops,

  	.qc_prep 	= ata_bmdma_dumb_qc_prep,

  	.qc_issue	= sc1200_qc_issue,

  	.qc_defer	= sc1200_qc_defer,

  	.cable_detect	= ata_cable_40wire,
  	.set_piomode	= sc1200_set_piomode,
  	.set_dmamode	= sc1200_set_dmamode,

  };

  
  /**
   *	sc1200_init_one		-	Initialise an SC1200
   *	@dev: PCI device
   *	@id: Entry in match table
   *
   *	Just throw the needed data at the libata helper and it does all
   *	our work.
   */

  static int sc1200_init_one(struct pci_dev *dev, const struct pci_device_id *id)
  {

  	static const struct ata_port_info info = {

  		.flags = ATA_FLAG_SLAVE_POSS,

  		.pio_mask = ATA_PIO4,
  		.mwdma_mask = ATA_MWDMA2,
  		.udma_mask = ATA_UDMA2,

  		.port_ops = &sc1200_port_ops
  	};

  	const struct ata_port_info *ppi[] = { &info, NULL };

  	return ata_pci_bmdma_init_one(dev, ppi, &sc1200_sht, NULL, 0);

  }

  static const struct pci_device_id sc1200[] = {
  	{ PCI_VDEVICE(NS, PCI_DEVICE_ID_NS_SCx200_IDE), },
  
  	{ },

  };
  
  static struct pci_driver sc1200_pci_driver = {

  	.name 		= DRV_NAME,

  	.id_table	= sc1200,
  	.probe 		= sc1200_init_one,

  	.remove		= ata_pci_remove_one,

  #ifdef CONFIG_PM

  	.suspend	= ata_pci_device_suspend,
  	.resume		= ata_pci_device_resume,

  #endif

  };
  
  static int __init sc1200_init(void)
  {
  	return pci_register_driver(&sc1200_pci_driver);
  }

  static void __exit sc1200_exit(void)
  {
  	pci_unregister_driver(&sc1200_pci_driver);
  }

  MODULE_AUTHOR("Alan Cox, Mark Lord");
  MODULE_DESCRIPTION("low-level driver for the NS/AMD SC1200");
  MODULE_LICENSE("GPL");
  MODULE_DEVICE_TABLE(pci, sc1200);
  MODULE_VERSION(DRV_VERSION);
  
  module_init(sc1200_init);
  module_exit(sc1200_exit);