[PATCH 2.6.11-rc4+] sata_qstor: new basic driver for Pacific Digital QStor

[Mark Lord <lsml@rtr.ca>]

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This is a new basic libata SATA driver
for the Pacific Digital QStor SATA/RAID card.

It features ordinary per-drive SATA with single-request DMA
for R/W commands, and PIO for everything else.

It currently does not implement any of the hardware RAID support,
nor hot-plug, nor the tagged/native command-queuing features.

On the other hand, it is small and simple as a result.

Patch is against 2.6.11-rc4 + minor libata updates from Jeff.

Signed-off-by: Mark Lord <mlord@pobox.com>

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diff -uprN linux-2.6.11-rc4jeff/drivers/scsi/Kconfig linux/drivers/scsi/Kconfig
--- linux-2.6.11-rc4jeff/drivers/scsi/Kconfig	2005-02-14 10:27:44.000000000 -0500
+++ linux/drivers/scsi/Kconfig	2005-02-16 20:29:23.000000000 -0500
@@ -457,6 +457,14 @@ config SCSI_SATA_PROMISE
 
 	  If unsure, say N.
 
+config SCSI_SATA_QSTOR
+	tristate "Pacific Digital SATA QStor support"
+	depends on SCSI_SATA && PCI
+	help
+	  This option enables support for Pacific Digital Serial ATA QStor.
+
+	  If unsure, say N.
+
 config SCSI_SATA_SX4
 	tristate "Promise SATA SX4 support"
 	depends on SCSI_SATA && PCI && EXPERIMENTAL
diff -uprN linux-2.6.11-rc4jeff/drivers/scsi/Makefile linux/drivers/scsi/Makefile
--- linux-2.6.11-rc4jeff/drivers/scsi/Makefile	2005-02-14 10:27:44.000000000 -0500
+++ linux/drivers/scsi/Makefile	2005-02-16 20:29:23.000000000 -0500
@@ -125,6 +125,7 @@ obj-$(CONFIG_SCSI_SATA_AHCI)	+= libata.o
 obj-$(CONFIG_SCSI_SATA_SVW)	+= libata.o sata_svw.o
 obj-$(CONFIG_SCSI_ATA_PIIX)	+= libata.o ata_piix.o
 obj-$(CONFIG_SCSI_SATA_PROMISE)	+= libata.o sata_promise.o
+obj-$(CONFIG_SCSI_SATA_QSTOR)	+= libata.o sata_qstor.o
 obj-$(CONFIG_SCSI_SATA_SIL)	+= libata.o sata_sil.o
 obj-$(CONFIG_SCSI_SATA_VIA)	+= libata.o sata_via.o
 obj-$(CONFIG_SCSI_SATA_VITESSE)	+= libata.o sata_vsc.o
diff -uprN linux-2.6.11-rc4jeff/drivers/scsi/sata_qstor.c linux/drivers/scsi/sata_qstor.c
--- linux-2.6.11-rc4jeff/drivers/scsi/sata_qstor.c	1969-12-31 19:00:00.000000000 -0500
+++ linux/drivers/scsi/sata_qstor.c	2005-02-16 20:25:01.000000000 -0500
@@ -0,0 +1,700 @@
+/*
+ *  sata_qstor.c - Pacific Digital Corporation QStor SATA
+ *
+ *  Maintained by:  Mark Lord <mlord@pobox.com>
+ *
+ *  Copyright 2005 Pacific Digital Corporation.
+ *  (OSL/GPL code release authorized by Jalil Fadavi).
+ *
+ *  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/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 <linux/sched.h>
+#include "scsi.h"
+#include <scsi/scsi_host.h>
+#include <asm/io.h>
+#include <linux/libata.h>
+
+#define DRV_NAME	"sata_qstor"
+#define DRV_VERSION	"0.03"
+
+enum {
+	QS_PORTS		= 4,
+	QS_MAX_PRD		= LIBATA_MAX_PRD,
+	QS_CPB_ORDER		= 6,
+	QS_CPB_BYTES		= (1 << QS_CPB_ORDER),
+	QS_PRD_BYTES		= QS_MAX_PRD * 16,
+	QS_PKT_BYTES		= QS_CPB_BYTES + QS_PRD_BYTES,
+
+	QS_DMA_BOUNDARY		= ~0UL,
+
+	/* global register offsets */
+	QS_HCF_CNFG3		= 0x0003, /* host configuration offset */
+	QS_HID_HPHY		= 0x0004, /* host physical interface info */
+	QS_HCT_CTRL		= 0x00e4, /* global interrupt mask offset */
+	QS_HST_SFF		= 0x0100, /* host status fifo offset */
+	QS_HVS_SERD3		= 0x0393, /* PHY enable offset */
+
+	/* global control bits */
+	QS_HPHY_64BIT		= (1 << 1), /* 64-bit bus detected */
+	QS_CNFG3_GSRST		= 0x01,     /* global chip reset */
+	QS_SERD3_PHY_ENA	= 0xf0,     /* PHY detection ENAble*/
+
+	/* per-channel register offsets */
+	QS_CCF_CPBA		= 0x0710, /* chan CPB base address */
+	QS_CCF_CSEP		= 0x0718, /* chan CPB separation factor */
+	QS_CFC_HUFT		= 0x0800, /* host upstream fifo threshold */
+	QS_CFC_HDFT		= 0x0804, /* host downstream fifo threshold */
+	QS_CFC_DUFT		= 0x0808, /* dev upstream fifo threshold */
+	QS_CFC_DDFT		= 0x080c, /* dev downstream fifo threshold */
+	QS_CCT_CTR0		= 0x0900, /* chan control-0 offset */
+	QS_CCT_CTR1		= 0x0901, /* chan control-1 offset */
+	QS_CCT_CFF		= 0x0a00, /* chan command fifo offset */
+
+	/* channel control bits */
+	QS_CTR0_REG		= (1 << 1),   /* register mode (vs. pkt mode) */
+	QS_CTR0_CLER		= (1 << 2),   /* clear channel errors */
+	QS_CTR1_RDEV		= (1 << 1),   /* sata phy/comms reset */
+	QS_CTR1_RCHN		= (1 << 4),   /* reset channel logic */
+	QS_CCF_RUN_PKT		= 0x107,      /* RUN a new dma PKT */
+
+	/* pkt sub-field headers */
+	QS_HCB_HDR		= 0x01,   /* Host Control Block header */
+	QS_DCB_HDR		= 0x02,   /* Device Control Block header */
+
+	/* pkt HCB flag bits */
+	QS_HF_DIRO		= (1 << 0),   /* data DIRection Out */
+	QS_HF_DAT		= (1 << 3),   /* DATa pkt */
+	QS_HF_IEN		= (1 << 4),   /* Interrupt ENable */
+	QS_HF_VLD		= (1 << 5),   /* VaLiD pkt */
+
+	/* pkt DCB flag bits */
+	QS_DF_PORD		= (1 << 2),   /* Pio OR Dma */
+	QS_DF_ELBA		= (1 << 3),   /* Extended LBA (lba48) */
+
+	/* PCI device IDs */
+	board_2068_idx		= 0,	/* QStor 4-port SATA/RAID */
+};
+
+typedef enum { qs_state_idle, qs_state_pkt, qs_state_mmio } qs_state_t;
+
+struct qs_port_priv {
+	u8			*pkt;
+	dma_addr_t		pkt_dma;
+	qs_state_t		state;
+};
+
+static u32 qs_scr_read (struct ata_port *ap, unsigned int sc_reg);
+static void qs_scr_write (struct ata_port *ap, unsigned int sc_reg, u32 val);
+static int qs_ata_init_one (struct pci_dev *pdev, const struct pci_device_id *ent);
+static irqreturn_t qs_intr (int irq, void *dev_instance, struct pt_regs *regs);
+static int qs_port_start(struct ata_port *ap);
+static void qs_host_stop(struct ata_host_set *host_set);
+static void qs_port_stop(struct ata_port *ap);
+static void qs_phy_reset(struct ata_port *ap);
+static void qs_qc_prep(struct ata_queued_cmd *qc);
+static int qs_qc_issue(struct ata_queued_cmd *qc);
+static int qs_check_atapi_dma(struct ata_queued_cmd *qc);
+static void qs_bmdma_stop(struct ata_port *ap);
+static u8 qs_bmdma_status(struct ata_port *ap);
+static void qs_irq_clear(struct ata_port *ap);
+
+static Scsi_Host_Template qs_ata_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		= QS_MAX_PRD,
+	.max_sectors		= ATA_MAX_SECTORS,
+	.cmd_per_lun		= ATA_SHT_CMD_PER_LUN,
+	.emulated		= ATA_SHT_EMULATED,
+	//FIXME .use_clustering		= ATA_SHT_USE_CLUSTERING,
+	.use_clustering		= ENABLE_CLUSTERING,
+	.proc_name		= DRV_NAME,
+	.dma_boundary		= QS_DMA_BOUNDARY,
+	.slave_configure	= ata_scsi_slave_config,
+	.bios_param		= ata_std_bios_param,
+};
+
+static struct ata_port_operations qs_ata_ops = {
+	.port_disable		= ata_port_disable,
+	.tf_load		= ata_tf_load,
+	.tf_read		= ata_tf_read,
+	.check_status		= ata_check_status,
+	.check_atapi_dma	= qs_check_atapi_dma,
+	.exec_command		= ata_exec_command,
+	.dev_select		= ata_std_dev_select,
+	.phy_reset		= qs_phy_reset,
+	.qc_prep		= qs_qc_prep,
+	.qc_issue		= qs_qc_issue,
+	.eng_timeout		= ata_eng_timeout,
+	.irq_handler		= qs_intr,
+	.irq_clear		= qs_irq_clear,
+	.scr_read		= qs_scr_read,
+	.scr_write		= qs_scr_write,
+	.port_start		= qs_port_start,
+	.port_stop		= qs_port_stop,
+	.host_stop		= qs_host_stop,
+	.bmdma_stop		= qs_bmdma_stop,
+	.bmdma_status		= qs_bmdma_status,
+};
+
+static struct ata_port_info qs_port_info[] = {
+	/* board_2068_idx */
+	{
+		.sht		= &qs_ata_sht,
+		.host_flags	= ATA_FLAG_SATA | ATA_FLAG_NO_LEGACY |
+				  ATA_FLAG_SATA_RESET |
+				  //FIXME ATA_FLAG_SRST |
+				  ATA_FLAG_MMIO,
+		.pio_mask	= 0x10, /* pio4 */
+		.udma_mask	= 0x7f, /* udma0-6 */
+		.port_ops	= &qs_ata_ops,
+	},
+};
+
+static struct pci_device_id qs_ata_pci_tbl[] = {
+	{ PCI_VENDOR_ID_PDC, 0x2068, PCI_ANY_ID, PCI_ANY_ID, 0, 0,
+	  board_2068_idx },
+
+	{ }	/* terminate list */
+};
+
+static struct pci_driver qs_ata_pci_driver = {
+	.name			= DRV_NAME,
+	.id_table		= qs_ata_pci_tbl,
+	.probe			= qs_ata_init_one,
+	.remove			= ata_pci_remove_one,
+};
+
+static int qs_check_atapi_dma(struct ata_queued_cmd *qc)
+{
+	return 1;	/* ATAPI DMA not supported */
+}
+
+static void qs_bmdma_stop(struct ata_port *ap)
+{
+	/* nothing */
+}
+
+static u8 qs_bmdma_status(struct ata_port *ap)
+{
+	return 0;
+}
+
+static void qs_irq_clear(struct ata_port *ap)
+{
+	/* nothing */
+}
+
+static void qs_enter_reg_mode(struct ata_port *ap)
+{
+	u8 __iomem *chan = ap->host_set->mmio_base + (ap->port_no * 0x4000);
+
+	writeb(QS_CTR0_REG, chan + QS_CCT_CTR0);
+	readb(chan + QS_CCT_CTR0);        /* flush */
+}
+
+static void qs_phy_reset(struct ata_port *ap)
+{
+	u8 __iomem *chan = ap->host_set->mmio_base + (ap->port_no * 0x4000);
+	struct qs_port_priv *pp = ap->private_data;
+
+	pp->state = qs_state_idle;
+	writeb(QS_CTR1_RCHN, chan + QS_CCT_CTR1);
+	qs_enter_reg_mode(ap);
+	sata_phy_reset(ap);
+}
+
+static u32 qs_scr_read (struct ata_port *ap, unsigned int sc_reg)
+{
+	if (sc_reg > SCR_CONTROL)
+		return ~0U;
+	return readl((void __iomem *)(ap->ioaddr.scr_addr + (sc_reg * 8)));
+}
+
+static void qs_scr_write (struct ata_port *ap, unsigned int sc_reg, u32 val)
+{
+	if (sc_reg > SCR_CONTROL)
+		return;
+	writel(val, (void __iomem *)(ap->ioaddr.scr_addr + (sc_reg * 8)));
+}
+
+static void qs_fill_sg(struct ata_queued_cmd *qc)
+{
+	struct scatterlist *sg = qc->sg;
+	struct ata_port *ap = qc->ap;
+	struct qs_port_priv *pp = ap->private_data;
+	unsigned int nelem;
+	u8 *prd = pp->pkt + QS_CPB_BYTES;
+
+	assert(sg != NULL);
+	assert(qc->n_elem > 0);
+
+	for (nelem = 0; nelem < qc->n_elem; nelem++,sg++) {
+		u64 addr;
+		u32 len;
+
+		addr = sg_dma_address(sg);
+		*(u64 *)prd = cpu_to_le64(addr);
+		prd += sizeof(u64);
+
+		len = sg_dma_len(sg);
+		*(u32 *)prd = cpu_to_le32(len);
+		prd += sizeof(u64);
+
+		VPRINTK("PRD[%u] = (0x%llX, 0x%X)\n", nelem,
+					(unsigned long long)addr, len);
+	}
+}
+
+static void qs_qc_prep(struct ata_queued_cmd *qc)
+{
+	struct qs_port_priv *pp = qc->ap->private_data;
+	u8 dflags = QS_DF_PORD, *buf = pp->pkt;
+	u8 hflags = QS_HF_DAT | QS_HF_IEN | QS_HF_VLD;
+	u64 addr;
+
+	VPRINTK("ENTER\n");
+
+	qs_enter_reg_mode(qc->ap);
+	if (qc->tf.protocol != ATA_PROT_DMA) {
+		ata_qc_prep(qc);
+		return;
+	}
+
+	qs_fill_sg(qc);
+
+	if ((qc->tf.flags & ATA_TFLAG_WRITE))
+		hflags |= QS_HF_DIRO;
+	if ((qc->tf.flags & ATA_TFLAG_LBA48))
+		dflags |= QS_DF_ELBA;
+
+	/* host control block (HCB) */
+	buf[ 0] = QS_HCB_HDR;
+	buf[ 1] = hflags;
+	*(u32 *)(&buf[ 4]) = cpu_to_le32(qc->nsect * ATA_SECT_SIZE);
+	*(u32 *)(&buf[ 8]) = cpu_to_le32(qc->n_elem);
+	addr = ((u64)pp->pkt_dma) + QS_CPB_BYTES;
+	*(u64 *)(&buf[16]) = cpu_to_le64(addr);
+
+	/* device control block (DCB) */
+	buf[24] = QS_DCB_HDR;
+	buf[28] = dflags;
+
+	/* frame information structure (FIS) */
+	ata_tf_to_fis(&qc->tf, &buf[32], 0);
+}
+
+static inline void qs_packet_start(struct ata_queued_cmd *qc)
+{
+	struct ata_port *ap = qc->ap;
+	u8 __iomem *chan = ap->host_set->mmio_base + (ap->port_no * 0x4000);
+
+	VPRINTK("ENTER, ap %p\n", ap);
+
+	writeb(QS_CTR0_CLER, chan + QS_CCT_CTR0);
+	wmb();                             /* flush PRDs and pkt to memory */
+	writel(QS_CCF_RUN_PKT, chan + QS_CCT_CFF);
+	readl(chan + QS_CCT_CFF);          /* flush */
+}
+
+static int qs_qc_issue(struct ata_queued_cmd *qc)
+{
+	struct qs_port_priv *pp = qc->ap->private_data;
+
+	switch (qc->tf.protocol) {
+	case ATA_PROT_DMA:
+
+		pp->state = qs_state_pkt;
+		qs_packet_start(qc);
+		return 0;
+
+	case ATA_PROT_ATAPI_DMA:
+		BUG();
+		break;
+
+	default:
+		break;
+	}
+
+	pp->state = qs_state_mmio;
+	return ata_qc_issue_prot(qc);
+}
+
+static inline unsigned int qs_intr_pkt(struct ata_host_set *host_set)
+{
+	unsigned int handled = 0;
+	u8 sFFE;
+	u8 __iomem *mmio_base = host_set->mmio_base;
+
+	do {
+		u32 sff0 = readl(mmio_base + QS_HST_SFF);
+		u32 sff1 = readl(mmio_base + QS_HST_SFF + 4);
+		u8 sEVLD = (sff1 >> 30) & 0x01;	/* valid flag */
+		sFFE  = sff1 >> 31;		/* empty flag */
+
+		if (sEVLD) {
+			u8 sDST = sff0 >> 16;	/* dev status */
+			u8 sHST = sff1 & 0x3f;	/* host status */
+			unsigned int port_no = (sff1 >> 8) & 0x03;
+			struct ata_port *ap = host_set->ports[port_no];
+
+			DPRINTK("SFF=%08x%08x: sCHAN=%u sHST=%d sDST=%02x\n",
+					sff1, sff0, port_no, sHST, sDST);
+			handled = 1;
+			if (ap && (!(ap->flags & ATA_FLAG_PORT_DISABLED))) {
+				struct ata_queued_cmd *qc;
+				struct qs_port_priv *pp = ap->private_data;
+				if (!pp || pp->state != qs_state_pkt)
+					continue;
+				qc = ata_qc_from_tag(ap, ap->active_tag);
+				if (qc && (!(qc->tf.ctl & ATA_NIEN))) {
+					switch (sHST) {
+					case 0: /* sucessful CPB */
+					case 3: /* device error */
+						pp->state = qs_state_idle;
+						qs_enter_reg_mode(qc->ap);
+						ata_qc_complete(qc, sDST);
+						break;
+					default:
+						break;
+					}
+				}
+			}
+		}
+	} while (!sFFE);
+	return handled;
+}
+
+static inline unsigned int qs_intr_mmio(struct ata_host_set *host_set)
+{
+	unsigned int handled = 0, port_no;
+
+	for (port_no = 0; port_no < host_set->n_ports; ++port_no) {
+		struct ata_port *ap;
+		ap = host_set->ports[port_no];
+		if (ap && (!(ap->flags & ATA_FLAG_PORT_DISABLED))) {
+			struct ata_queued_cmd *qc;
+			struct qs_port_priv *pp = ap->private_data;
+			if (!pp || pp->state != qs_state_mmio)
+				continue;
+			qc = ata_qc_from_tag(ap, ap->active_tag);
+			if (qc && (!(qc->tf.ctl & ATA_NIEN))) {
+
+				/* check main status, clearing INTRQ */
+				u8 status = ata_chk_status(ap);
+				if ((status & ATA_BUSY))
+					continue;
+				DPRINTK("ata%u: protocol %d (dev_stat 0x%X)\n",
+					ap->id, qc->tf.protocol, status);
+		
+				/* complete taskfile transaction */
+				pp->state = qs_state_idle;
+				ata_qc_complete(qc, status);
+				handled = 1;
+			}
+		}
+	}
+	return handled;
+}
+
+static irqreturn_t qs_intr(int irq, void *dev_instance, struct pt_regs *regs)
+{
+	struct ata_host_set *host_set = dev_instance;
+	unsigned int handled = 0;
+
+	VPRINTK("ENTER\n");
+
+	spin_lock(&host_set->lock);
+	handled  = qs_intr_pkt(host_set) | qs_intr_mmio(host_set);
+	spin_unlock(&host_set->lock);
+
+	VPRINTK("EXIT\n");
+
+	return IRQ_RETVAL(handled);
+}
+
+static void qs_ata_setup_port(struct ata_ioports *port, unsigned long base)
+{
+	port->cmd_addr		=
+	port->data_addr		= base + 0x400;
+	port->error_addr	=
+	port->feature_addr	= base + 0x408; /* hob_feature = 0x409 */
+	port->nsect_addr	= base + 0x410; /* hob_nsect   = 0x411 */
+	port->lbal_addr		= base + 0x418; /* hob_lbal    = 0x419 */
+	port->lbam_addr		= base + 0x420; /* hob_lbam    = 0x421 */
+	port->lbah_addr		= base + 0x428; /* hob_lbah    = 0x429 */
+	port->device_addr	= base + 0x430;
+	port->status_addr	=
+	port->command_addr	= base + 0x438;
+	port->altstatus_addr	=
+	port->ctl_addr		= base + 0x440;
+	port->scr_addr		= base + 0xc00;
+}
+
+static int qs_port_start(struct ata_port *ap)
+{
+	struct device *dev = ap->host_set->dev;
+	struct qs_port_priv *pp;
+	void __iomem *mmio_base = ap->host_set->mmio_base;
+	void __iomem *chan = mmio_base + (ap->port_no * 0x4000);
+	u64 addr;
+	int rc;
+
+	rc = ata_port_start(ap);
+	if (rc)
+		return rc;
+	qs_enter_reg_mode(ap);
+	pp = kcalloc(1, sizeof(*pp), GFP_KERNEL);
+	if (!pp) {
+		rc = -ENOMEM;
+		goto err_out;
+	}
+	pp->pkt = dma_alloc_coherent(dev, QS_PKT_BYTES, &pp->pkt_dma,
+								GFP_KERNEL);
+	if (!pp->pkt) {
+		rc = -ENOMEM;
+		goto err_out_kfree;
+	}
+	memset(pp->pkt, 0, QS_PKT_BYTES);
+	ap->private_data = pp;
+
+	addr = (u64)pp->pkt_dma;
+	writel((u32) addr,        chan + QS_CCF_CPBA);
+	writel((u32)(addr >> 32), chan + QS_CCF_CPBA + 4);
+	return 0;
+
+err_out_kfree:
+	kfree(pp);
+err_out:
+	ata_port_stop(ap);
+	return rc;
+}
+
+static void qs_port_stop(struct ata_port *ap)
+{
+	struct device *dev = ap->host_set->dev;
+	struct qs_port_priv *pp = ap->private_data;
+
+	if (pp != NULL) {
+		ap->private_data = NULL;
+		if (pp->pkt != NULL)
+			dma_free_coherent(dev, QS_PKT_BYTES, pp->pkt,
+								pp->pkt_dma);
+		kfree(pp);
+	}
+	ata_port_stop(ap);
+}
+
+static void qs_host_stop(struct ata_host_set *host_set)
+{
+	void __iomem *mmio_base = host_set->mmio_base;
+
+	writeb(0, mmio_base + QS_HCT_CTRL); /* disable host interrupts */
+	writeb(QS_CNFG3_GSRST, mmio_base + QS_HCF_CNFG3); /* global reset */
+}
+
+static void qs_host_init(unsigned int chip_id, struct ata_probe_ent *pe)
+{
+	void __iomem *mmio_base = pe->mmio_base;
+	unsigned int port_no;
+
+	writeb(0, mmio_base + QS_HCT_CTRL); /* disable host interrupts */
+	writeb(QS_CNFG3_GSRST, mmio_base + QS_HCF_CNFG3); /* global reset */
+
+	/* reset each channel in turn */
+	for (port_no = 0; port_no < pe->n_ports; ++port_no) {
+		u8 __iomem *chan = mmio_base + (port_no * 0x4000);
+		writeb(QS_CTR1_RDEV|QS_CTR1_RCHN, chan + QS_CCT_CTR1);
+		writeb(QS_CTR0_REG, chan + QS_CCT_CTR0);
+		readb(chan + QS_CCT_CTR0);        /* flush */
+	}
+	writeb(QS_SERD3_PHY_ENA, mmio_base + QS_HVS_SERD3); /* enable phy */
+
+	for (port_no = 0; port_no < pe->n_ports; ++port_no) {
+		u8 __iomem *chan = mmio_base + (port_no * 0x4000);
+		/* set FIFO depths to same settings as Windows driver */
+		writew(32, chan + QS_CFC_HUFT);
+		writew(32, chan + QS_CFC_HDFT);
+		writew(10, chan + QS_CFC_DUFT);
+		writew( 8, chan + QS_CFC_DDFT);
+		/* set CPB size in bytes, as a power of two */
+		writeb(QS_CPB_ORDER,    chan + QS_CCF_CSEP);
+	}
+	writeb(1, mmio_base + QS_HCT_CTRL); /* enable host interrupts */
+}
+
+/*
+ * The QStor understands 64-bit buses, and uses 64-bit fields
+ * for DMA pointers regardless of bus width.  We just have to
+ * make sure our DMA masks are set appropriately for whatever
+ * bridge lies between us and the QStor, and then the DMA mapping
+ * code will ensure we only ever "see" appropriate buffer addresses.
+ * If we're 32-bit limited somewhere, then our 64-bit fields will
+ * just end up with zeros in the upper 32-bits, without any special
+ * logic required outside of this routine (below).
+ */
+static int qs_set_dma_masks(struct pci_dev *pdev, void __iomem *mmio_base)
+{
+	u32 bus_info = readl(mmio_base + QS_HID_HPHY);
+	int rc, have_64bit_bus = (bus_info & QS_HPHY_64BIT);
+
+	if (have_64bit_bus &&
+	    !pci_set_dma_mask(pdev, 0xffffffffffffffffULL)) {
+		rc = pci_set_consistent_dma_mask(pdev, 0xffffffffffffffffULL);
+		if (rc) {
+			rc = pci_set_consistent_dma_mask(pdev, 0xffffffffULL);
+			if (rc) {
+				printk(KERN_ERR DRV_NAME
+					"(%s): 64-bit DMA enable failed\n",
+					pci_name(pdev));
+				return rc;
+			}
+		}
+	} else {
+		rc = pci_set_dma_mask(pdev, 0xffffffffULL);
+		if (rc) {
+			printk(KERN_ERR DRV_NAME
+				"(%s): 32-bit DMA enable failed\n",
+				pci_name(pdev));
+			return rc;
+		}
+		rc = pci_set_consistent_dma_mask(pdev, 0xffffffffULL);
+		if (rc) {
+			printk(KERN_ERR DRV_NAME
+				"(%s): 32-bit consistent DMA enable failed\n",
+				pci_name(pdev));
+			return rc;
+		}
+	}
+	return 0;
+}
+
+static int qs_ata_init_one(struct pci_dev *pdev,
+				const struct pci_device_id *ent)
+{
+	static int printed_version;
+	struct ata_probe_ent *probe_ent = NULL;
+	void __iomem *mmio_base;
+	unsigned int board_idx = (unsigned int) ent->driver_data;
+	int rc, port_no;
+
+	if (!printed_version++)
+		printk(KERN_DEBUG DRV_NAME " version " DRV_VERSION "\n");
+
+	rc = pci_enable_device(pdev);
+	if (rc)
+		return rc;
+
+	rc = pci_request_regions(pdev, DRV_NAME);
+	if (rc)
+		goto err_out;
+
+	if ((pci_resource_flags(pdev, 4) & IORESOURCE_MEM) == 0) {
+		rc = -ENODEV;
+		goto err_out_regions;
+	}
+
+	mmio_base = ioremap(pci_resource_start(pdev, 4),
+		            pci_resource_len(pdev, 4));
+	if (mmio_base == NULL) {
+		rc = -ENOMEM;
+		goto err_out_regions;
+	}
+
+	rc = qs_set_dma_masks(pdev, mmio_base);
+	if (rc)
+		goto err_out_iounmap;
+
+	probe_ent = kmalloc(sizeof(*probe_ent), GFP_KERNEL);
+	if (probe_ent == NULL) {
+		rc = -ENOMEM;
+		goto err_out_iounmap;
+	}
+
+	memset(probe_ent, 0, sizeof(*probe_ent));
+	probe_ent->dev = pci_dev_to_dev(pdev);
+	INIT_LIST_HEAD(&probe_ent->node);
+
+	probe_ent->sht		= qs_port_info[board_idx].sht;
+	probe_ent->host_flags	= qs_port_info[board_idx].host_flags;
+	probe_ent->pio_mask	= qs_port_info[board_idx].pio_mask;
+	probe_ent->mwdma_mask	= qs_port_info[board_idx].mwdma_mask;
+	probe_ent->udma_mask	= qs_port_info[board_idx].udma_mask;
+	probe_ent->port_ops	= qs_port_info[board_idx].port_ops;
+
+	probe_ent->irq		= pdev->irq;
+	probe_ent->irq_flags	= SA_SHIRQ;
+	probe_ent->mmio_base	= mmio_base;
+	probe_ent->n_ports	= QS_PORTS;
+
+	for (port_no = 0; port_no < probe_ent->n_ports; ++port_no) {
+		unsigned long chan = (unsigned long)mmio_base +
+							(port_no * 0x4000);
+		qs_ata_setup_port(&probe_ent->port[port_no], chan);
+	}
+
+	pci_set_master(pdev);
+
+	/* initialize adapter */
+	qs_host_init(board_idx, probe_ent);
+
+	rc = ata_device_add(probe_ent);
+	kfree(probe_ent);
+	if (rc != QS_PORTS)
+		goto err_out_iounmap;
+	return 0;
+
+err_out_iounmap:
+	iounmap(mmio_base);
+err_out_regions:
+	pci_release_regions(pdev);
+err_out:
+	pci_disable_device(pdev);
+	return rc;
+}
+
+static int __init qs_ata_init(void)
+{
+	return pci_module_init(&qs_ata_pci_driver);
+}
+
+static void __exit qs_ata_exit(void)
+{
+	pci_unregister_driver(&qs_ata_pci_driver);
+}
+
+MODULE_AUTHOR("Mark Lord");
+MODULE_DESCRIPTION("Pacific Digital Corporation QStor SATA low-level driver");
+MODULE_LICENSE("GPL");
+MODULE_DEVICE_TABLE(pci, qs_ata_pci_tbl);
+MODULE_VERSION(DRV_VERSION);
+
+module_init(qs_ata_init);
+module_exit(qs_ata_exit);