/*
 * 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\n",
		ata->cyc8b, ata->setup, ata->act8b, ata->rec8b);

	dev_dbg(dev, "SMC: C=%d S=%d P=%d NS=%d NP=%d\n",
		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\n", 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\n", 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_MMIO | 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);