/*
   * pata_cmd640.c 	- CMD640 PCI PATA for new ATA layer
   *			  (C) 2007 Red Hat Inc
   *
   * Based upon
   *  linux/drivers/ide/pci/cmd640.c		Version 1.02  Sep 01, 1996
   *
   *  Copyright (C) 1995-1996  Linus Torvalds & authors (see driver)
   *
   *	This drives only the PCI version of the controller. If you have a
   *	VLB one then we have enough docs to support it but you can write
   *	your own code.
   */
  
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/pci.h>
  #include <linux/blkdev.h>
  #include <linux/delay.h>
  #include <linux/gfp.h>
  #include <scsi/scsi_host.h>
  #include <linux/libata.h>
  
  #define DRV_NAME "pata_cmd640"
  #define DRV_VERSION "0.0.5"
  
  struct cmd640_reg {
  	int last;
  	u8 reg58[ATA_MAX_DEVICES];
  };
  
  enum {
  	CFR = 0x50,
  	CNTRL = 0x51,
  	CMDTIM = 0x52,
  	ARTIM0 = 0x53,
  	DRWTIM0 = 0x54,
  	ARTIM23 = 0x57,
  	DRWTIM23 = 0x58,
  	BRST = 0x59
  };
  
  /**
   *	cmd640_set_piomode	-	set initial PIO mode data
   *	@ap: ATA port
   *	@adev: ATA device
   *
   *	Called to do the PIO mode setup.
   */
  
  static void cmd640_set_piomode(struct ata_port *ap, struct ata_device *adev)
  {
  	struct cmd640_reg *timing = ap->private_data;
  	struct pci_dev *pdev = to_pci_dev(ap->host->dev);
  	struct ata_timing t;
  	const unsigned long T = 1000000 / 33;
  	const u8 setup_data[] = { 0x40, 0x40, 0x40, 0x80, 0x00 };
  	u8 reg;
  	int arttim = ARTIM0 + 2 * adev->devno;
  	struct ata_device *pair = ata_dev_pair(adev);
  
  	if (ata_timing_compute(adev, adev->pio_mode, &t, T, 0) < 0) {
  		printk(KERN_ERR DRV_NAME ": mode computation failed.
  ");
  		return;
  	}
  
  	/* The second channel has shared timings and the setup timing is
  	   messy to switch to merge it for worst case */
  	if (ap->port_no && pair) {
  		struct ata_timing p;
  		ata_timing_compute(pair, pair->pio_mode, &p, T, 1);
  		ata_timing_merge(&p, &t, &t, ATA_TIMING_SETUP);
  	}
  
  	/* Make the timings fit */
  	if (t.recover > 16) {
  		t.active += t.recover - 16;
  		t.recover = 16;
  	}
  	if (t.active > 16)
  		t.active = 16;
  
  	/* Now convert the clocks into values we can actually stuff into
  	   the chip */
  
  	if (t.recover > 1)
  		t.recover--;	/* 640B only */
  	else
  		t.recover = 15;
  
  	if (t.setup > 4)
  		t.setup = 0xC0;
  	else
  		t.setup = setup_data[t.setup];
  
  	if (ap->port_no == 0) {
  		t.active &= 0x0F;	/* 0 = 16 */
  
  		/* Load setup timing */
  		pci_read_config_byte(pdev, arttim, &reg);
  		reg &= 0x3F;
  		reg |= t.setup;
  		pci_write_config_byte(pdev, arttim, reg);
  
  		/* Load active/recovery */
  		pci_write_config_byte(pdev, arttim + 1, (t.active << 4) | t.recover);
  	} else {
  		/* Save the shared timings for channel, they will be loaded
  		   by qc_issue. Reloading the setup time is expensive so we
  		   keep a merged one loaded */
  		pci_read_config_byte(pdev, ARTIM23, &reg);
  		reg &= 0x3F;
  		reg |= t.setup;
  		pci_write_config_byte(pdev, ARTIM23, reg);
  		timing->reg58[adev->devno] = (t.active << 4) | t.recover;
  	}
  }
  
  
  /**
   *	cmd640_qc_issue	-	command preparation hook
   *	@qc: Command to be issued
   *
   *	Channel 1 has shared timings. We must reprogram the
   *	clock each drive 2/3 switch we do.
   */
  
  static unsigned int cmd640_qc_issue(struct ata_queued_cmd *qc)
  {
  	struct ata_port *ap = qc->ap;
  	struct ata_device *adev = qc->dev;
  	struct pci_dev *pdev = to_pci_dev(ap->host->dev);
  	struct cmd640_reg *timing = ap->private_data;
  
  	if (ap->port_no != 0 && adev->devno != timing->last) {
  		pci_write_config_byte(pdev, DRWTIM23, timing->reg58[adev->devno]);
  		timing->last = adev->devno;
  	}
  	return ata_sff_qc_issue(qc);
  }
  
  /**
   *	cmd640_port_start	-	port setup
   *	@ap: ATA port being set up
   *
   *	The CMD640 needs to maintain private data structures so we
   *	allocate space here.
   */
  
  static int cmd640_port_start(struct ata_port *ap)
  {
  	struct pci_dev *pdev = to_pci_dev(ap->host->dev);
  	struct cmd640_reg *timing;
  
  	timing = devm_kzalloc(&pdev->dev, sizeof(struct cmd640_reg), GFP_KERNEL);
  	if (timing == NULL)
  		return -ENOMEM;
  	timing->last = -1;	/* Force a load */
  	ap->private_data = timing;
  	return 0;
  }
  
  static bool cmd640_sff_irq_check(struct ata_port *ap)
  {
  	struct pci_dev *pdev	= to_pci_dev(ap->host->dev);
  	int irq_reg		= ap->port_no ? ARTIM23 : CFR;
  	u8  irq_stat, irq_mask	= ap->port_no ? 0x10 : 0x04;
  
  	pci_read_config_byte(pdev, irq_reg, &irq_stat);
  
  	return irq_stat & irq_mask;
  }
  
  static struct scsi_host_template cmd640_sht = {
  	ATA_PIO_SHT(DRV_NAME),
  };
  
  static struct ata_port_operations cmd640_port_ops = {
  	.inherits	= &ata_sff_port_ops,
  	/* In theory xfer_noirq is not needed once we kill the prefetcher */
  	.sff_data_xfer	= ata_sff_data_xfer_noirq,
  	.sff_irq_check	= cmd640_sff_irq_check,
  	.qc_issue	= cmd640_qc_issue,
  	.cable_detect	= ata_cable_40wire,
  	.set_piomode	= cmd640_set_piomode,
  	.port_start	= cmd640_port_start,
  };
  
  static void cmd640_hardware_init(struct pci_dev *pdev)
  {
  	u8 ctrl;
  
  	/* CMD640 detected, commiserations */
  	pci_write_config_byte(pdev, 0x5B, 0x00);
  	/* PIO0 command cycles */
  	pci_write_config_byte(pdev, CMDTIM, 0);
  	/* 512 byte bursts (sector) */
  	pci_write_config_byte(pdev, BRST, 0x40);
  	/*
  	 * A reporter a long time ago
  	 * Had problems with the data fifo
  	 * So don't run the risk
  	 * Of putting crap on the disk
  	 * For its better just to go slow
  	 */
  	/* Do channel 0 */
  	pci_read_config_byte(pdev, CNTRL, &ctrl);
  	pci_write_config_byte(pdev, CNTRL, ctrl | 0xC0);
  	/* Ditto for channel 1 */
  	pci_read_config_byte(pdev, ARTIM23, &ctrl);
  	ctrl |= 0x0C;
  	pci_write_config_byte(pdev, ARTIM23, ctrl);
  }
  
  static int cmd640_init_one(struct pci_dev *pdev, const struct pci_device_id *id)
  {
  	static const struct ata_port_info info = {
  		.flags = ATA_FLAG_SLAVE_POSS,
  		.pio_mask = ATA_PIO4,
  		.port_ops = &cmd640_port_ops
  	};
  	const struct ata_port_info *ppi[] = { &info, NULL };
  	int rc;
  
  	rc = pcim_enable_device(pdev);
  	if (rc)
  		return rc;
  
  	cmd640_hardware_init(pdev);
  
  	return ata_pci_sff_init_one(pdev, ppi, &cmd640_sht, NULL, 0);
  }
  
  #ifdef CONFIG_PM_SLEEP
  static int cmd640_reinit_one(struct pci_dev *pdev)
  {
  	struct ata_host *host = pci_get_drvdata(pdev);
  	int rc;
  
  	rc = ata_pci_device_do_resume(pdev);
  	if (rc)
  		return rc;
  	cmd640_hardware_init(pdev);
  	ata_host_resume(host);
  	return 0;
  }
  #endif
  
  static const struct pci_device_id cmd640[] = {
  	{ PCI_VDEVICE(CMD, 0x640), 0 },
  	{ },
  };
  
  static struct pci_driver cmd640_pci_driver = {
  	.name 		= DRV_NAME,
  	.id_table	= cmd640,
  	.probe 		= cmd640_init_one,
  	.remove		= ata_pci_remove_one,
  #ifdef CONFIG_PM_SLEEP
  	.suspend	= ata_pci_device_suspend,
  	.resume		= cmd640_reinit_one,
  #endif
  };
  
  module_pci_driver(cmd640_pci_driver);
  
  MODULE_AUTHOR("Alan Cox");
  MODULE_DESCRIPTION("low-level driver for CMD640 PATA controllers");
  MODULE_LICENSE("GPL");
  MODULE_DEVICE_TABLE(pci, cmd640);
  MODULE_VERSION(DRV_VERSION);