/*
 *  sata_svw.c - ServerWorks / Apple K2 SATA
 *
 *  Maintained by: Benjamin Herrenschmidt <benh@kernel.crashing.org> and
 *		   Jeff Garzik <jgarzik@pobox.com>
 *  		    Please ALWAYS copy linux-ide@vger.kernel.org
 *		    on emails.
 *
 *  Copyright 2003 Benjamin Herrenschmidt <benh@kernel.crashing.org>
 *
 *  Bits from Jeff Garzik, Copyright RedHat, Inc.
 *
 *  This driver probably works with non-Apple versions of the
 *  Broadcom chipset...
 *
 *  The contents of this file are subject to the Open
 *  Software License version 1.1 that can be found at
 *  http://www.opensource.org/licenses/osl-1.1.txt and is included herein
 *  by reference.
 *
 *  Alternatively, the contents of this file may be used under the terms
 *  of the GNU General Public License version 2 (the "GPL") as distributed
 *  in the kernel source COPYING file, in which case the provisions of
 *  the GPL are applicable instead of the above.  If you wish to allow
 *  the use of your version of this file only under the terms of the
 *  GPL and not to allow others to use your version of this file under
 *  the OSL, indicate your decision by deleting the provisions above and
 *  replace them with the notice and other provisions required by the GPL.
 *  If you do not delete the provisions above, a recipient may use your
 *  version of this file under either the OSL or the GPL.
 *
 */

#include <linux/config.h>
#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 <linux/interrupt.h>
#include "scsi.h"
#include <scsi/scsi_host.h>
#include <linux/libata.h>

#ifdef CONFIG_PPC_OF
#include <asm/prom.h>
#include <asm/pci-bridge.h>
#endif /* CONFIG_PPC_OF */

#define DRV_NAME	"sata_svw"
#define DRV_VERSION	"1.05"

/* Taskfile registers offsets */
#define K2_SATA_TF_CMD_OFFSET		0x00
#define K2_SATA_TF_DATA_OFFSET		0x00
#define K2_SATA_TF_ERROR_OFFSET		0x04
#define K2_SATA_TF_NSECT_OFFSET		0x08
#define K2_SATA_TF_LBAL_OFFSET		0x0c
#define K2_SATA_TF_LBAM_OFFSET		0x10
#define K2_SATA_TF_LBAH_OFFSET		0x14
#define K2_SATA_TF_DEVICE_OFFSET	0x18
#define K2_SATA_TF_CMDSTAT_OFFSET      	0x1c
#define K2_SATA_TF_CTL_OFFSET		0x20

/* DMA base */
#define K2_SATA_DMA_CMD_OFFSET		0x30

/* SCRs base */
#define K2_SATA_SCR_STATUS_OFFSET	0x40
#define K2_SATA_SCR_ERROR_OFFSET	0x44
#define K2_SATA_SCR_CONTROL_OFFSET	0x48

/* Others */
#define K2_SATA_SICR1_OFFSET		0x80
#define K2_SATA_SICR2_OFFSET		0x84
#define K2_SATA_SIM_OFFSET		0x88

/* Port stride */
#define K2_SATA_PORT_OFFSET		0x100


static u32 k2_sata_scr_read (struct ata_port *ap, unsigned int sc_reg)
{
	if (sc_reg > SCR_CONTROL)
		return 0xffffffffU;
	return readl((void *) ap->ioaddr.scr_addr + (sc_reg * 4));
}


static void k2_sata_scr_write (struct ata_port *ap, unsigned int sc_reg,
			       u32 val)
{
	if (sc_reg > SCR_CONTROL)
		return;
	writel(val, (void *) ap->ioaddr.scr_addr + (sc_reg * 4));
}


static void k2_sata_tf_load(struct ata_port *ap, struct ata_taskfile *tf)
{
	struct ata_ioports *ioaddr = &ap->ioaddr;
	unsigned int is_addr = tf->flags & ATA_TFLAG_ISADDR;

	if (tf->ctl != ap->last_ctl) {
		writeb(tf->ctl, ioaddr->ctl_addr);
		ap->last_ctl = tf->ctl;
		ata_wait_idle(ap);
	}
	if (is_addr && (tf->flags & ATA_TFLAG_LBA48)) {
		writew(tf->feature | (((u16)tf->hob_feature) << 8), ioaddr->feature_addr);
		writew(tf->nsect | (((u16)tf->hob_nsect) << 8), ioaddr->nsect_addr);
		writew(tf->lbal | (((u16)tf->hob_lbal) << 8), ioaddr->lbal_addr);
		writew(tf->lbam | (((u16)tf->hob_lbam) << 8), ioaddr->lbam_addr);
		writew(tf->lbah | (((u16)tf->hob_lbah) << 8), ioaddr->lbah_addr);
	} else if (is_addr) {
		writew(tf->feature, ioaddr->feature_addr);
		writew(tf->nsect, ioaddr->nsect_addr);
		writew(tf->lbal, ioaddr->lbal_addr);
		writew(tf->lbam, ioaddr->lbam_addr);
		writew(tf->lbah, ioaddr->lbah_addr);
	}

	if (tf->flags & ATA_TFLAG_DEVICE)
		writeb(tf->device, ioaddr->device_addr);

	ata_wait_idle(ap);
}


static void k2_sata_tf_read(struct ata_port *ap, struct ata_taskfile *tf)
{
	struct ata_ioports *ioaddr = &ap->ioaddr;
	u16 nsect, lbal, lbam, lbah;

	nsect = tf->nsect = readw(ioaddr->nsect_addr);
	lbal = tf->lbal = readw(ioaddr->lbal_addr);
	lbam = tf->lbam = readw(ioaddr->lbam_addr);
	lbah = tf->lbah = readw(ioaddr->lbah_addr);
	tf->device = readw(ioaddr->device_addr);

	if (tf->flags & ATA_TFLAG_LBA48) {
		tf->hob_feature = readw(ioaddr->error_addr) >> 8;
		tf->hob_nsect = nsect >> 8;
		tf->hob_lbal = lbal >> 8;
		tf->hob_lbam = lbam >> 8;
		tf->hob_lbah = lbah >> 8;
        }
}

/**
 *	k2_bmdma_setup_mmio - Set up PCI IDE BMDMA transaction (MMIO)
 *	@qc: Info associated with this ATA transaction.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host_set lock)
 */

static void k2_bmdma_setup_mmio (struct ata_queued_cmd *qc)
{
	struct ata_port *ap = qc->ap;
	unsigned int rw = (qc->tf.flags & ATA_TFLAG_WRITE);
	u8 dmactl;
	void *mmio = (void *) ap->ioaddr.bmdma_addr;
	/* load PRD table addr. */
	mb();	/* make sure PRD table writes are visible to controller */
	writel(ap->prd_dma, mmio + ATA_DMA_TABLE_OFS);

	/* specify data direction, triple-check start bit is clear */
	dmactl = readb(mmio + ATA_DMA_CMD);
	dmactl &= ~(ATA_DMA_WR | ATA_DMA_START);
	if (!rw)
		dmactl |= ATA_DMA_WR;
	writeb(dmactl, mmio + ATA_DMA_CMD);

	/* issue r/w command if this is not a ATA DMA command*/
	if (qc->tf.protocol != ATA_PROT_DMA)
		ap->ops->exec_command(ap, &qc->tf);
}

/**
 *	k2_bmdma_start_mmio - Start a PCI IDE BMDMA transaction (MMIO)
 *	@qc: Info associated with this ATA transaction.
 *
 *	LOCKING:
 *	spin_lock_irqsave(host_set lock)
 */

static void k2_bmdma_start_mmio (struct ata_queued_cmd *qc)
{
	struct ata_port *ap = qc->ap;
	void *mmio = (void *) ap->ioaddr.bmdma_addr;
	u8 dmactl;

	/* start host DMA transaction */
	dmactl = readb(mmio + ATA_DMA_CMD);
	writeb(dmactl | ATA_DMA_START, mmio + ATA_DMA_CMD);
	/* There is a race condition in certain SATA controllers that can 
	   be seen when the r/w command is given to the controller before the 
	   host DMA is started. On a Read command, the controller would initiate
	   the command to the drive even before it sees the DMA start. When there
	   are very fast drives connected to the controller, or when the data request 
	   hits in the drive cache, there is the possibility that the drive returns a part
	   or all of the requested data to the controller before the DMA start is issued.
	   In this case, the controller would become confused as to what to do with the data.
	   In the worst case when all the data is returned back to the controller, the
	   controller could hang. In other cases it could return partial data returning
	   in data corruption. This problem has been seen in PPC systems and can also appear
	   on an system with very fast disks, where the SATA controller is sitting behind a 
	   number of bridges, and hence there is significant latency between the r/w command
	   and the start command. */
	/* issue r/w command if the access is to ATA*/
	if (qc->tf.protocol == ATA_PROT_DMA)
		ap->ops->exec_command(ap, &qc->tf);
}

									      
static u8 k2_stat_check_status(struct ata_port *ap)
{
       	return readl((void *) ap->ioaddr.status_addr);
}

#ifdef CONFIG_PPC_OF
/*
 * k2_sata_proc_info
 * inout : decides on the direction of the dataflow and the meaning of the
 *	   variables
 * buffer: If inout==FALSE data is being written to it else read from it
 * *start: If inout==FALSE start of the valid data in the buffer
 * offset: If inout==FALSE offset from the beginning of the imaginary file
 *	   from which we start writing into the buffer
 * length: If inout==FALSE max number of bytes to be written into the buffer
 *	   else number of bytes in the buffer
 */
static int k2_sata_proc_info(struct Scsi_Host *shost, char *page, char **start,
			     off_t offset, int count, int inout)
{
	struct ata_port *ap;
	struct device_node *np;
	int len, index;

	/* Find  the ata_port */
	ap = (struct ata_port *) &shost->hostdata[0];
	if (ap == NULL)
		return 0;

	/* Find the OF node for the PCI device proper */
	np = pci_device_to_OF_node(to_pci_dev(ap->host_set->dev));
	if (np == NULL)
		return 0;

	/* Match it to a port node */
	index = (ap == ap->host_set->ports[0]) ? 0 : 1;
	for (np = np->child; np != NULL; np = np->sibling) {
		u32 *reg = (u32 *)get_property(np, "reg", NULL);
		if (!reg)
			continue;
		if (index == *reg)
			break;
	}
	if (np == NULL)
		return 0;

	len = sprintf(page, "devspec: %s\n", np->full_name);

	return len;
}
#endif /* CONFIG_PPC_OF */


static Scsi_Host_Template k2_sata_sht = {
	.module			= THIS_MODULE,
	.name			= DRV_NAME,
	.ioctl			= ata_scsi_ioctl,
	.queuecommand		= ata_scsi_queuecmd,
	.eh_strategy_handler	= ata_scsi_error,
	.can_queue		= ATA_DEF_QUEUE,
	.this_id		= ATA_SHT_THIS_ID,
	.sg_tablesize		= LIBATA_MAX_PRD,
	.max_sectors		= ATA_MAX_SECTORS,
	.cmd_per_lun		= ATA_SHT_CMD_PER_LUN,
	.emulated		= ATA_SHT_EMULATED,
	.use_clustering		= ATA_SHT_USE_CLUSTERING,
	.proc_name		= DRV_NAME,
	.dma_boundary		= ATA_DMA_BOUNDARY,
	.slave_configure	= ata_scsi_slave_config,
#ifdef CONFIG_PPC_OF
	.proc_info		= k2_sata_proc_info,
#endif
	.bios_param		= ata_std_bios_param,
	.ordered_flush		= 1,
};


static struct ata_port_operations k2_sata_ops = {
	.port_disable		= ata_port_disable,
	.tf_load		= k2_sata_tf_load,
	.tf_read		= k2_sata_tf_read,
	.check_status		= k2_stat_check_status,
	.exec_command		= ata_exec_command,
	.dev_select		= ata_std_dev_select,
	.phy_reset		= sata_phy_reset,
	.bmdma_setup		= k2_bmdma_setup_mmio,
	.bmdma_start		= k2_bmdma_start_mmio,
	.bmdma_stop		= ata_bmdma_stop,
	.bmdma_status		= ata_bmdma_status,
	.qc_prep		= ata_qc_prep,
	.qc_issue		= ata_qc_issue_prot,
	.eng_timeout		= ata_eng_timeout,
	.irq_handler		= ata_interrupt,
	.irq_clear		= ata_bmdma_irq_clear,
	.scr_read		= k2_sata_scr_read,
	.scr_write		= k2_sata_scr_write,
	.port_start		= ata_port_start,
	.port_stop		= ata_port_stop,
};

static void k2_sata_setup_port(struct ata_ioports *port, unsigned long base)
{
	port->cmd_addr		= base + K2_SATA_TF_CMD_OFFSET;
	port->data_addr		= base + K2_SATA_TF_DATA_OFFSET;
	port->feature_addr	=
	port->error_addr	= base + K2_SATA_TF_ERROR_OFFSET;
	port->nsect_addr	= base + K2_SATA_TF_NSECT_OFFSET;
	port->lbal_addr		= base + K2_SATA_TF_LBAL_OFFSET;
	port->lbam_addr		= base + K2_SATA_TF_LBAM_OFFSET;
	port->lbah_addr		= base + K2_SATA_TF_LBAH_OFFSET;
	port->device_addr	= base + K2_SATA_TF_DEVICE_OFFSET;
	port->command_addr	=
	port->status_addr	= base + K2_SATA_TF_CMDSTAT_OFFSET;
	port->altstatus_addr	=
	port->ctl_addr		= base + K2_SATA_TF_CTL_OFFSET;
	port->bmdma_addr	= base + K2_SATA_DMA_CMD_OFFSET;
	port->scr_addr		= base + K2_SATA_SCR_STATUS_OFFSET;
}


static int k2_sata_init_one (struct pci_dev *pdev, const struct pci_device_id *ent)
{
	static int printed_version;
	struct ata_probe_ent *probe_ent = NULL;
	unsigned long base;
	void *mmio_base;
	int pci_dev_busy = 0;
	int rc;

	if (!printed_version++)
		printk(KERN_DEBUG DRV_NAME " version " DRV_VERSION "\n");

	/*
	 * If this driver happens to only be useful on Apple's K2, then
	 * we should check that here as it has a normal Serverworks ID
	 */
	rc = pci_enable_device(pdev);
	if (rc)
		return rc;
	/*
	 * Check if we have resources mapped at all (second function may
	 * have been disabled by firmware)
	 */
	if (pci_resource_len(pdev, 5) == 0)
		return -ENODEV;

	/* Request PCI regions */
	rc = pci_request_regions(pdev, DRV_NAME);
	if (rc) {
		pci_dev_busy = 1;
		goto err_out;
	}

	rc = pci_set_dma_mask(pdev, ATA_DMA_MASK);
	if (rc)
		goto err_out_regions;
	rc = pci_set_consistent_dma_mask(pdev, ATA_DMA_MASK);
	if (rc)
		goto err_out_regions;

	probe_ent = kmalloc(sizeof(*probe_ent), GFP_KERNEL);
	if (probe_ent == NULL) {
		rc = -ENOMEM;
		goto err_out_regions;
	}

	memset(probe_ent, 0, sizeof(*probe_ent));
	probe_ent->dev = pci_dev_to_dev(pdev);
	INIT_LIST_HEAD(&probe_ent->node);

	mmio_base = ioremap(pci_resource_start(pdev, 5),
		            pci_resource_len(pdev, 5));
	if (mmio_base == NULL) {
		rc = -ENOMEM;
		goto err_out_free_ent;
	}
	base = (unsigned long) mmio_base;

	/* Clear a magic bit in SCR1 according to Darwin, those help
	 * some funky seagate drives (though so far, those were already
	 * set by the firmware on the machines I had access to
	 */
	writel(readl(mmio_base + K2_SATA_SICR1_OFFSET) & ~0x00040000,
	       mmio_base + K2_SATA_SICR1_OFFSET);

	/* Clear SATA error & interrupts we don't use */
	writel(0xffffffff, mmio_base + K2_SATA_SCR_ERROR_OFFSET);
	writel(0x0, mmio_base + K2_SATA_SIM_OFFSET);

	probe_ent->sht = &k2_sata_sht;
	probe_ent->host_flags = ATA_FLAG_SATA | ATA_FLAG_SATA_RESET |
				ATA_FLAG_NO_LEGACY | ATA_FLAG_MMIO;
	probe_ent->port_ops = &k2_sata_ops;
	probe_ent->n_ports = 4;
	probe_ent->irq = pdev->irq;
	probe_ent->irq_flags = SA_SHIRQ;
	probe_ent->mmio_base = mmio_base;

	/* We don't care much about the PIO/UDMA masks, but the core won't like us
	 * if we don't fill these
	 */
	probe_ent->pio_mask = 0x1f;
	probe_ent->mwdma_mask = 0x7;
	probe_ent->udma_mask = 0x7f;

	/* We have 4 ports per PCI function */
	k2_sata_setup_port(&probe_ent->port[0], base + 0 * K2_SATA_PORT_OFFSET);
	k2_sata_setup_port(&probe_ent->port[1], base + 1 * K2_SATA_PORT_OFFSET);
	k2_sata_setup_port(&probe_ent->port[2], base + 2 * K2_SATA_PORT_OFFSET);
	k2_sata_setup_port(&probe_ent->port[3], base + 3 * K2_SATA_PORT_OFFSET);

	pci_set_master(pdev);

	/* FIXME: check ata_device_add return value */
	ata_device_add(probe_ent);
	kfree(probe_ent);

	return 0;

err_out_free_ent:
	kfree(probe_ent);
err_out_regions:
	pci_release_regions(pdev);
err_out:
	if (!pci_dev_busy)
		pci_disable_device(pdev);
	return rc;
}


static struct pci_device_id k2_sata_pci_tbl[] = {
	{ 0x1166, 0x0240, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0 },
	{ 0x1166, 0x0241, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0 },
	{ 0x1166, 0x0242, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0 },
	{ }
};


static struct pci_driver k2_sata_pci_driver = {
	.name			= DRV_NAME,
	.id_table		= k2_sata_pci_tbl,
	.probe			= k2_sata_init_one,
	.remove			= ata_pci_remove_one,
};


static int __init k2_sata_init(void)
{
	return pci_module_init(&k2_sata_pci_driver);
}


static void __exit k2_sata_exit(void)
{
	pci_unregister_driver(&k2_sata_pci_driver);
}


MODULE_AUTHOR("Benjamin Herrenschmidt");
MODULE_DESCRIPTION("low-level driver for K2 SATA controller");
MODULE_LICENSE("GPL");
MODULE_DEVICE_TABLE(pci, k2_sata_pci_tbl);
MODULE_VERSION(DRV_VERSION);

module_init(k2_sata_init);
module_exit(k2_sata_exit);