/*
   * AVR32 SMC/CFC PATA Driver
   *
   * Copyright (C) 2007 Atmel Norway
   *
   * 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.
   */
  
  #define DEBUG
  
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/device.h>
  #include <linux/platform_device.h>
  #include <linux/delay.h>
  #include <linux/interrupt.h>
  #include <linux/irq.h>

  #include <linux/slab.h>

  #include <scsi/scsi_host.h>
  #include <linux/ata.h>
  #include <linux/libata.h>
  #include <linux/err.h>
  #include <linux/io.h>

  #include <mach/board.h>
  #include <mach/smc.h>

  
  #define DRV_NAME "pata_at32"

  #define DRV_VERSION "0.0.3"

  
  /*
   * CompactFlash controller memory layout relative to the base address:
   *
   *	Attribute memory:  0000 0000 -> 003f ffff
   *	Common memory:	   0040 0000 -> 007f ffff
   *	I/O memory:	   0080 0000 -> 00bf ffff
   *	True IDE Mode:	   00c0 0000 -> 00df ffff
   *	Alt IDE Mode:	   00e0 0000 -> 00ff ffff
   *
   * Only True IDE and Alt True IDE mode are needed for this driver.
   *
   *	True IDE mode	  => CS0 = 0, CS1 = 1 (cmd, error, stat, etc)
   *	Alt True IDE mode => CS0 = 1, CS1 = 0 (ctl, alt_stat)
   */
  #define CF_IDE_OFFSET	  0x00c00000
  #define CF_ALT_IDE_OFFSET 0x00e00000
  #define CF_RES_SIZE	  2048
  
  /*
   * Define DEBUG_BUS if you are doing debugging of your own EBI -> PATA
   * adaptor with a logic analyzer or similar.
   */
  #undef DEBUG_BUS
  
  /*
   * ATA PIO modes
   *
   *	Name	| Mb/s	| Min cycle time | Mask
   *	--------+-------+----------------+--------
   *	Mode 0	| 3.3	| 600 ns	 | 0x01
   *	Mode 1	| 5.2	| 383 ns	 | 0x03
   *	Mode 2	| 8.3	| 240 ns	 | 0x07
   *	Mode 3	| 11.1	| 180 ns	 | 0x0f
   *	Mode 4	| 16.7	| 120 ns	 | 0x1f

   *
   * Alter PIO_MASK below according to table to set maximal PIO mode.

   */

  enum {
    PIO_MASK = ATA_PIO4,
  };

  
  /*
   * Struct containing private information about device.
   */
  struct at32_ide_info {
  	unsigned int		irq;
  	struct resource		res_ide;
  	struct resource		res_alt;
  	void __iomem		*ide_addr;
  	void __iomem		*alt_addr;
  	unsigned int		cs;
  	struct smc_config	smc;
  };
  
  /*
   * Setup SMC for the given ATA timing.
   */
  static int pata_at32_setup_timing(struct device *dev,
  				  struct at32_ide_info *info,

  				  const struct ata_timing *ata)

  {

  	struct smc_config *smc = &info->smc;

  	struct smc_timing timing;

  
  	int active;
  	int recover;

  	memset(&timing, 0, sizeof(struct smc_timing));

  	/* Total cycle time */

  	timing.read_cycle  = ata->cyc8b;

  
  	/* DIOR <= CFIOR timings */

  	timing.nrd_setup   = ata->setup;
  	timing.nrd_pulse   = ata->act8b;
  	timing.nrd_recover = ata->rec8b;
  
  	/* Convert nanosecond timing to clock cycles */
  	smc_set_timing(smc, &timing);

  	/* Add one extra cycle setup due to signal ring */
  	smc->nrd_setup = smc->nrd_setup + 1;
  
  	active  = smc->nrd_setup + smc->nrd_pulse;

  	recover = smc->read_cycle - active;

  	/* Need at least two cycles recovery */
  	if (recover < 2)
  	  smc->read_cycle = active + 2;

  
  	/* (CS0, CS1, DIR, OE) <= (CFCE1, CFCE2, CFRNW, NCSX) timings */

  	smc->ncs_read_setup = 1;
  	smc->ncs_read_pulse = smc->read_cycle - 2;

  
  	/* Write timings same as read timings */
  	smc->write_cycle = smc->read_cycle;
  	smc->nwe_setup = smc->nrd_setup;
  	smc->nwe_pulse = smc->nrd_pulse;
  	smc->ncs_write_setup = smc->ncs_read_setup;
  	smc->ncs_write_pulse = smc->ncs_read_pulse;

  	/* Do some debugging output of ATA and SMC timings */
  	dev_dbg(dev, "ATA: C=%d S=%d P=%d R=%d
  ",
  		ata->cyc8b, ata->setup, ata->act8b, ata->rec8b);
  
  	dev_dbg(dev, "SMC: C=%d S=%d P=%d NS=%d NP=%d
  ",

  		smc->read_cycle, smc->nrd_setup, smc->nrd_pulse,

  		smc->ncs_read_setup, smc->ncs_read_pulse);

  
  	/* Finally, configure the SMC */
  	return smc_set_configuration(info->cs, smc);
  }
  
  /*
   * Procedures for libATA.
   */
  static void pata_at32_set_piomode(struct ata_port *ap, struct ata_device *adev)
  {
  	struct ata_timing timing;
  	struct at32_ide_info *info = ap->host->private_data;
  
  	int ret;
  
  	/* Compute ATA timing */
  	ret = ata_timing_compute(adev, adev->pio_mode, &timing, 1000, 0);
  	if (ret) {
  		dev_warn(ap->dev, "Failed to compute ATA timing %d
  ", ret);
  		return;
  	}
  
  	/* Setup SMC to ATA timing */
  	ret = pata_at32_setup_timing(ap->dev, info, &timing);
  	if (ret) {
  		dev_warn(ap->dev, "Failed to setup ATA timing %d
  ", ret);
  		return;
  	}
  }

  static struct scsi_host_template at32_sht = {

  	ATA_PIO_SHT(DRV_NAME),

  };
  
  static struct ata_port_operations at32_port_ops = {

  	.inherits		= &ata_sff_port_ops,

  	.cable_detect		= ata_cable_40wire,

  	.set_piomode		= pata_at32_set_piomode,

  };
  
  static int __init pata_at32_init_one(struct device *dev,
  				     struct at32_ide_info *info)
  {
  	struct ata_host *host;
  	struct ata_port *ap;
  
  	host = ata_host_alloc(dev, 1);
  	if (!host)
  		return -ENOMEM;
  
  	ap = host->ports[0];
  
  	/* Setup ATA bindings */
  	ap->ops	     = &at32_port_ops;
  	ap->pio_mask = PIO_MASK;

  	ap->flags   |= ATA_FLAG_SLAVE_POSS;

  
  	/*
  	 * Since all 8-bit taskfile transfers has to go on the lower
  	 * byte of the data bus and there is a bug in the SMC that
  	 * makes it impossible to alter the bus width during runtime,
  	 * we need to hardwire the address signals as follows:
  	 *
  	 *	A_IDE(2:0) <= A_EBI(3:1)
  	 *
  	 * This makes all addresses on the EBI even, thus all data
  	 * will be on the lower byte of the data bus.  All addresses
  	 * used by libATA need to be altered according to this.
  	 */
  	ap->ioaddr.altstatus_addr = info->alt_addr + (0x06 << 1);
  	ap->ioaddr.ctl_addr	  = info->alt_addr + (0x06 << 1);
  
  	ap->ioaddr.data_addr	  = info->ide_addr + (ATA_REG_DATA << 1);
  	ap->ioaddr.error_addr	  = info->ide_addr + (ATA_REG_ERR << 1);
  	ap->ioaddr.feature_addr	  = info->ide_addr + (ATA_REG_FEATURE << 1);
  	ap->ioaddr.nsect_addr	  = info->ide_addr + (ATA_REG_NSECT << 1);
  	ap->ioaddr.lbal_addr	  = info->ide_addr + (ATA_REG_LBAL << 1);
  	ap->ioaddr.lbam_addr	  = info->ide_addr + (ATA_REG_LBAM << 1);
  	ap->ioaddr.lbah_addr	  = info->ide_addr + (ATA_REG_LBAH << 1);
  	ap->ioaddr.device_addr	  = info->ide_addr + (ATA_REG_DEVICE << 1);
  	ap->ioaddr.status_addr	  = info->ide_addr + (ATA_REG_STATUS << 1);
  	ap->ioaddr.command_addr	  = info->ide_addr + (ATA_REG_CMD << 1);
  
  	/* Set info as private data of ATA host */
  	host->private_data = info;
  
  	/* Register ATA device and return */

  	return ata_host_activate(host, info->irq, ata_sff_interrupt,

  				 IRQF_SHARED | IRQF_TRIGGER_RISING,
  				 &at32_sht);
  }
  
  /*
   * This function may come in handy for people analyzing their own
   * EBI -> PATA adaptors.
   */
  #ifdef DEBUG_BUS
  
  static void __init pata_at32_debug_bus(struct device *dev,
  				       struct at32_ide_info *info)
  {
  	const int d1 = 0xff;
  	const int d2 = 0x00;
  
  	int i;
  
  	/* Write 8-bit values (registers) */
  	iowrite8(d1, info->alt_addr + (0x06 << 1));
  	iowrite8(d2, info->alt_addr + (0x06 << 1));
  
  	for (i = 0; i < 8; i++) {
  		iowrite8(d1, info->ide_addr + (i << 1));
  		iowrite8(d2, info->ide_addr + (i << 1));
  	}
  
  	/* Write 16 bit values (data) */
  	iowrite16(d1,	   info->ide_addr);
  	iowrite16(d1 << 8, info->ide_addr);
  
  	iowrite16(d1,	   info->ide_addr);
  	iowrite16(d1 << 8, info->ide_addr);
  }
  
  #endif
  
  static int __init pata_at32_probe(struct platform_device *pdev)
  {
  	const struct ata_timing initial_timing =
  		{XFER_PIO_0, 70, 290, 240, 600, 165, 150, 600, 0};
  
  	struct device		 *dev = &pdev->dev;
  	struct at32_ide_info	 *info;
  	struct ide_platform_data *board = pdev->dev.platform_data;
  	struct resource		 *res;
  
  	int irq;
  	int ret;
  
  	if (!board)
  		return -ENXIO;
  
  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	if (!res)
  		return -ENXIO;
  
  	/* Retrive IRQ */
  	irq = platform_get_irq(pdev, 0);
  	if (irq < 0)
  		return irq;

  	/* Setup struct containing private information */

  	info = kzalloc(sizeof(struct at32_ide_info), GFP_KERNEL);
  	if (!info)
  		return -ENOMEM;

  	info->irq = irq;
  	info->cs  = board->cs;
  
  	/* Request memory resources */
  	info->res_ide.start = res->start + CF_IDE_OFFSET;
  	info->res_ide.end   = info->res_ide.start + CF_RES_SIZE - 1;
  	info->res_ide.name  = "ide";
  	info->res_ide.flags = IORESOURCE_MEM;
  
  	ret = request_resource(res, &info->res_ide);
  	if (ret)
  		goto err_req_res_ide;
  
  	info->res_alt.start = res->start + CF_ALT_IDE_OFFSET;
  	info->res_alt.end   = info->res_alt.start + CF_RES_SIZE - 1;
  	info->res_alt.name  = "alt";
  	info->res_alt.flags = IORESOURCE_MEM;
  
  	ret = request_resource(res, &info->res_alt);
  	if (ret)
  		goto err_req_res_alt;
  
  	/* Setup non-timing elements of SMC */
  	info->smc.bus_width	 = 2; /* 16 bit data bus */
  	info->smc.nrd_controlled = 1; /* Sample data on rising edge of NRD */
  	info->smc.nwe_controlled = 0; /* Drive data on falling edge of NCS */
  	info->smc.nwait_mode	 = 3; /* NWAIT is in READY mode */
  	info->smc.byte_write	 = 0; /* Byte select access type */
  	info->smc.tdf_mode	 = 0; /* TDF optimization disabled */
  	info->smc.tdf_cycles	 = 0; /* No TDF wait cycles */

  	/* Setup SMC to ATA timing */

  	ret = pata_at32_setup_timing(dev, info, &initial_timing);
  	if (ret)
  		goto err_setup_timing;

  	/* Map ATA address space */

  	ret = -ENOMEM;
  	info->ide_addr = devm_ioremap(dev, info->res_ide.start, 16);
  	info->alt_addr = devm_ioremap(dev, info->res_alt.start, 16);
  	if (!info->ide_addr || !info->alt_addr)
  		goto err_ioremap;
  
  #ifdef DEBUG_BUS
  	pata_at32_debug_bus(dev, info);
  #endif

  	/* Setup and register ATA device */

  	ret = pata_at32_init_one(dev, info);
  	if (ret)
  		goto err_ata_device;
  
  	return 0;
  
   err_ata_device:
   err_ioremap:
   err_setup_timing:
  	release_resource(&info->res_alt);
   err_req_res_alt:
  	release_resource(&info->res_ide);
   err_req_res_ide:
  	kfree(info);
  
  	return ret;
  }
  
  static int __exit pata_at32_remove(struct platform_device *pdev)
  {
  	struct ata_host *host = platform_get_drvdata(pdev);
  	struct at32_ide_info *info;
  
  	if (!host)
  		return 0;
  
  	info = host->private_data;
  	ata_host_detach(host);
  
  	if (!info)
  		return 0;
  
  	release_resource(&info->res_ide);
  	release_resource(&info->res_alt);
  
  	kfree(info);
  
  	return 0;
  }

  /* work with hotplug and coldplug */
  MODULE_ALIAS("platform:at32_ide");

  static struct platform_driver pata_at32_driver = {
  	.remove	       = __exit_p(pata_at32_remove),
  	.driver	       = {
  		.name  = "at32_ide",
  		.owner = THIS_MODULE,
  	},
  };
  
  static int __init pata_at32_init(void)
  {
  	return platform_driver_probe(&pata_at32_driver, pata_at32_probe);
  }
  
  static void __exit pata_at32_exit(void)
  {
  	platform_driver_unregister(&pata_at32_driver);
  }
  
  module_init(pata_at32_init);
  module_exit(pata_at32_exit);
  
  MODULE_LICENSE("GPL");
  MODULE_DESCRIPTION("AVR32 SMC/CFC PATA Driver");
  MODULE_AUTHOR("Kristoffer Nyborg Gregertsen <kngregertsen@norway.atmel.com>");
  MODULE_VERSION(DRV_VERSION);