// SPDX-License-Identifier: GPL-2.0-or-later

  /*
   *  pdc_adma.c - Pacific Digital Corporation ADMA
   *

   *  Maintained by:  Tejun Heo <tj@kernel.org>

   *
   *  Copyright 2005 Mark Lord
   *

   *  libata documentation is available via 'make {ps|pdf}docs',

   *  as Documentation/driver-api/libata.rst

   *

   *  Supports ATA disks in single-packet ADMA mode.
   *  Uses PIO for everything else.
   *
   *  TODO:  Use ADMA transfers for ATAPI devices, when possible.
   *  This requires careful attention to a number of quirks of the chip.

   */
  
  #include <linux/kernel.h>
  #include <linux/module.h>

  #include <linux/gfp.h>

  #include <linux/pci.h>

  #include <linux/blkdev.h>
  #include <linux/delay.h>
  #include <linux/interrupt.h>

  #include <linux/device.h>

  #include <scsi/scsi_host.h>

  #include <linux/libata.h>
  
  #define DRV_NAME	"pdc_adma"

  #define DRV_VERSION	"1.0"

  
  /* macro to calculate base address for ATA regs */

  #define ADMA_ATA_REGS(base, port_no)	((base) + ((port_no) * 0x40))

  
  /* macro to calculate base address for ADMA regs */

  #define ADMA_REGS(base, port_no)	((base) + 0x80 + ((port_no) * 0x20))

  /* macro to obtain addresses from ata_port */
  #define ADMA_PORT_REGS(ap) \
  	ADMA_REGS((ap)->host->iomap[ADMA_MMIO_BAR], ap->port_no)

  
  enum {

  	ADMA_MMIO_BAR		= 4,

  	ADMA_PORTS		= 2,
  	ADMA_CPB_BYTES		= 40,
  	ADMA_PRD_BYTES		= LIBATA_MAX_PRD * 16,
  	ADMA_PKT_BYTES		= ADMA_CPB_BYTES + ADMA_PRD_BYTES,
  
  	ADMA_DMA_BOUNDARY	= 0xffffffff,
  
  	/* global register offsets */
  	ADMA_MODE_LOCK		= 0x00c7,
  
  	/* per-channel register offsets */
  	ADMA_CONTROL		= 0x0000, /* ADMA control */
  	ADMA_STATUS		= 0x0002, /* ADMA status */
  	ADMA_CPB_COUNT		= 0x0004, /* CPB count */
  	ADMA_CPB_CURRENT	= 0x000c, /* current CPB address */
  	ADMA_CPB_NEXT		= 0x000c, /* next CPB address */
  	ADMA_CPB_LOOKUP		= 0x0010, /* CPB lookup table */
  	ADMA_FIFO_IN		= 0x0014, /* input FIFO threshold */
  	ADMA_FIFO_OUT		= 0x0016, /* output FIFO threshold */
  
  	/* ADMA_CONTROL register bits */
  	aNIEN			= (1 << 8), /* irq mask: 1==masked */
  	aGO			= (1 << 7), /* packet trigger ("Go!") */
  	aRSTADM			= (1 << 5), /* ADMA logic reset */

  	aPIOMD4			= 0x0003,   /* PIO mode 4 */
  
  	/* ADMA_STATUS register bits */
  	aPSD			= (1 << 6),
  	aUIRQ			= (1 << 4),
  	aPERR			= (1 << 0),
  
  	/* CPB bits */
  	cDONE			= (1 << 0),

  	cATERR			= (1 << 3),

  	cVLD			= (1 << 0),
  	cDAT			= (1 << 2),
  	cIEN			= (1 << 3),
  
  	/* PRD bits */
  	pORD			= (1 << 4),
  	pDIRO			= (1 << 5),
  	pEND			= (1 << 7),
  
  	/* ATA register flags */
  	rIGN			= (1 << 5),
  	rEND			= (1 << 7),
  
  	/* ATA register addresses */
  	ADMA_REGS_CONTROL	= 0x0e,
  	ADMA_REGS_SECTOR_COUNT	= 0x12,
  	ADMA_REGS_LBA_LOW	= 0x13,
  	ADMA_REGS_LBA_MID	= 0x14,
  	ADMA_REGS_LBA_HIGH	= 0x15,
  	ADMA_REGS_DEVICE	= 0x16,
  	ADMA_REGS_COMMAND	= 0x17,
  
  	/* PCI device IDs */
  	board_1841_idx		= 0,	/* ADMA 2-port controller */
  };
  
  typedef enum { adma_state_idle, adma_state_pkt, adma_state_mmio } adma_state_t;
  
  struct adma_port_priv {
  	u8			*pkt;
  	dma_addr_t		pkt_dma;
  	adma_state_t		state;
  };

  static int adma_ata_init_one(struct pci_dev *pdev,

  				const struct pci_device_id *ent);

  static int adma_port_start(struct ata_port *ap);

  static void adma_port_stop(struct ata_port *ap);

  static enum ata_completion_errors adma_qc_prep(struct ata_queued_cmd *qc);

  static unsigned int adma_qc_issue(struct ata_queued_cmd *qc);

  static int adma_check_atapi_dma(struct ata_queued_cmd *qc);

  static void adma_freeze(struct ata_port *ap);
  static void adma_thaw(struct ata_port *ap);

  static int adma_prereset(struct ata_link *link, unsigned long deadline);

  static struct scsi_host_template adma_ata_sht = {

  	ATA_BASE_SHT(DRV_NAME),

  	.sg_tablesize		= LIBATA_MAX_PRD,

  	.dma_boundary		= ADMA_DMA_BOUNDARY,

  };

  static struct ata_port_operations adma_ata_ops = {

  	.inherits		= &ata_sff_port_ops,

  	.lost_interrupt		= ATA_OP_NULL,

  	.check_atapi_dma	= adma_check_atapi_dma,

  	.qc_prep		= adma_qc_prep,
  	.qc_issue		= adma_qc_issue,

  	.freeze			= adma_freeze,
  	.thaw			= adma_thaw,

  	.prereset		= adma_prereset,

  	.port_start		= adma_port_start,
  	.port_stop		= adma_port_stop,

  };
  
  static struct ata_port_info adma_port_info[] = {
  	/* board_1841_idx */
  	{

  		.flags		= ATA_FLAG_SLAVE_POSS | ATA_FLAG_PIO_POLLING,

  		.pio_mask	= ATA_PIO4_ONLY,

  		.udma_mask	= ATA_UDMA4,

  		.port_ops	= &adma_ata_ops,
  	},
  };

  static const struct pci_device_id adma_ata_pci_tbl[] = {

  	{ PCI_VDEVICE(PDC, 0x1841), board_1841_idx },

  
  	{ }	/* terminate list */
  };
  
  static struct pci_driver adma_ata_pci_driver = {
  	.name			= DRV_NAME,
  	.id_table		= adma_ata_pci_tbl,
  	.probe			= adma_ata_init_one,
  	.remove			= ata_pci_remove_one,
  };
  
  static int adma_check_atapi_dma(struct ata_queued_cmd *qc)
  {
  	return 1;	/* ATAPI DMA not yet supported */
  }

  static void adma_reset_engine(struct ata_port *ap)

  {

  	void __iomem *chan = ADMA_PORT_REGS(ap);

  	/* reset ADMA to idle state */
  	writew(aPIOMD4 | aNIEN | aRSTADM, chan + ADMA_CONTROL);
  	udelay(2);
  	writew(aPIOMD4, chan + ADMA_CONTROL);
  	udelay(2);
  }
  
  static void adma_reinit_engine(struct ata_port *ap)
  {
  	struct adma_port_priv *pp = ap->private_data;

  	void __iomem *chan = ADMA_PORT_REGS(ap);

  
  	/* mask/clear ATA interrupts */

  	writeb(ATA_NIEN, ap->ioaddr.ctl_addr);

  	ata_sff_check_status(ap);

  
  	/* reset the ADMA engine */

  	adma_reset_engine(ap);

  
  	/* set in-FIFO threshold to 0x100 */
  	writew(0x100, chan + ADMA_FIFO_IN);
  
  	/* set CPB pointer */
  	writel((u32)pp->pkt_dma, chan + ADMA_CPB_NEXT);
  
  	/* set out-FIFO threshold to 0x100 */
  	writew(0x100, chan + ADMA_FIFO_OUT);
  
  	/* set CPB count */
  	writew(1, chan + ADMA_CPB_COUNT);
  
  	/* read/discard ADMA status */
  	readb(chan + ADMA_STATUS);
  }
  
  static inline void adma_enter_reg_mode(struct ata_port *ap)
  {

  	void __iomem *chan = ADMA_PORT_REGS(ap);

  
  	writew(aPIOMD4, chan + ADMA_CONTROL);
  	readb(chan + ADMA_STATUS);	/* flush */
  }

  static void adma_freeze(struct ata_port *ap)

  {

  	void __iomem *chan = ADMA_PORT_REGS(ap);
  
  	/* mask/clear ATA interrupts */
  	writeb(ATA_NIEN, ap->ioaddr.ctl_addr);

  	ata_sff_check_status(ap);

  
  	/* reset ADMA to idle state */
  	writew(aPIOMD4 | aNIEN | aRSTADM, chan + ADMA_CONTROL);
  	udelay(2);
  	writew(aPIOMD4 | aNIEN, chan + ADMA_CONTROL);
  	udelay(2);
  }

  static void adma_thaw(struct ata_port *ap)
  {

  	adma_reinit_engine(ap);

  }

  static int adma_prereset(struct ata_link *link, unsigned long deadline)

  {

  	struct ata_port *ap = link->ap;

  	struct adma_port_priv *pp = ap->private_data;
  
  	if (pp->state != adma_state_idle) /* healthy paranoia */
  		pp->state = adma_state_mmio;
  	adma_reinit_engine(ap);

  	return ata_sff_prereset(link, deadline);

  }

  static int adma_fill_sg(struct ata_queued_cmd *qc)
  {

  	struct scatterlist *sg;

  	struct ata_port *ap = qc->ap;
  	struct adma_port_priv *pp = ap->private_data;

  	u8  *buf = pp->pkt, *last_buf = NULL;

  	int i = (2 + buf[3]) * 8;

  	u8 pFLAGS = pORD | ((qc->tf.flags & ATA_TFLAG_WRITE) ? pDIRO : 0);

  	unsigned int si;

  	for_each_sg(qc->sg, sg, qc->n_elem, si) {

  		u32 addr;
  		u32 len;
  
  		addr = (u32)sg_dma_address(sg);
  		*(__le32 *)(buf + i) = cpu_to_le32(addr);
  		i += 4;
  
  		len = sg_dma_len(sg) >> 3;
  		*(__le32 *)(buf + i) = cpu_to_le32(len);
  		i += 4;

  		last_buf = &buf[i];

  		buf[i++] = pFLAGS;
  		buf[i++] = qc->dev->dma_mode & 0xf;
  		buf[i++] = 0;	/* pPKLW */
  		buf[i++] = 0;	/* reserved */

  		*(__le32 *)(buf + i) =
  			(pFLAGS & pEND) ? 0 : cpu_to_le32(pp->pkt_dma + i + 4);

  		i += 4;

  		VPRINTK("PRD[%u] = (0x%lX, 0x%X)
  ", i/4,

  					(unsigned long)addr, len);
  	}

  
  	if (likely(last_buf))
  		*last_buf |= pEND;

  	return i;
  }

  static enum ata_completion_errors adma_qc_prep(struct ata_queued_cmd *qc)

  {
  	struct adma_port_priv *pp = qc->ap->private_data;
  	u8  *buf = pp->pkt;
  	u32 pkt_dma = (u32)pp->pkt_dma;
  	int i = 0;
  
  	VPRINTK("ENTER
  ");
  
  	adma_enter_reg_mode(qc->ap);

  	if (qc->tf.protocol != ATA_PROT_DMA)

  		return AC_ERR_OK;

  
  	buf[i++] = 0;	/* Response flags */
  	buf[i++] = 0;	/* reserved */
  	buf[i++] = cVLD | cDAT | cIEN;
  	i++;		/* cLEN, gets filled in below */
  
  	*(__le32 *)(buf+i) = cpu_to_le32(pkt_dma);	/* cNCPB */
  	i += 4;		/* cNCPB */
  	i += 4;		/* cPRD, gets filled in below */
  
  	buf[i++] = 0;	/* reserved */
  	buf[i++] = 0;	/* reserved */
  	buf[i++] = 0;	/* reserved */
  	buf[i++] = 0;	/* reserved */
  
  	/* ATA registers; must be a multiple of 4 */
  	buf[i++] = qc->tf.device;
  	buf[i++] = ADMA_REGS_DEVICE;
  	if ((qc->tf.flags & ATA_TFLAG_LBA48)) {
  		buf[i++] = qc->tf.hob_nsect;
  		buf[i++] = ADMA_REGS_SECTOR_COUNT;
  		buf[i++] = qc->tf.hob_lbal;
  		buf[i++] = ADMA_REGS_LBA_LOW;
  		buf[i++] = qc->tf.hob_lbam;
  		buf[i++] = ADMA_REGS_LBA_MID;
  		buf[i++] = qc->tf.hob_lbah;
  		buf[i++] = ADMA_REGS_LBA_HIGH;
  	}
  	buf[i++] = qc->tf.nsect;
  	buf[i++] = ADMA_REGS_SECTOR_COUNT;
  	buf[i++] = qc->tf.lbal;
  	buf[i++] = ADMA_REGS_LBA_LOW;
  	buf[i++] = qc->tf.lbam;
  	buf[i++] = ADMA_REGS_LBA_MID;
  	buf[i++] = qc->tf.lbah;
  	buf[i++] = ADMA_REGS_LBA_HIGH;
  	buf[i++] = 0;
  	buf[i++] = ADMA_REGS_CONTROL;
  	buf[i++] = rIGN;
  	buf[i++] = 0;
  	buf[i++] = qc->tf.command;
  	buf[i++] = ADMA_REGS_COMMAND | rEND;
  
  	buf[3] = (i >> 3) - 2;				/* cLEN */
  	*(__le32 *)(buf+8) = cpu_to_le32(pkt_dma + i);	/* cPRD */
  
  	i = adma_fill_sg(qc);
  	wmb();	/* flush PRDs and pkt to memory */
  #if 0
  	/* dump out CPB + PRDs for debug */
  	{
  		int j, len = 0;
  		static char obuf[2048];
  		for (j = 0; j < i; ++j) {
  			len += sprintf(obuf+len, "%02x ", buf[j]);
  			if ((j & 7) == 7) {
  				printk("%s
  ", obuf);
  				len = 0;
  			}
  		}
  		if (len)
  			printk("%s
  ", obuf);
  	}
  #endif

  	return AC_ERR_OK;

  }
  
  static inline void adma_packet_start(struct ata_queued_cmd *qc)
  {
  	struct ata_port *ap = qc->ap;

  	void __iomem *chan = ADMA_PORT_REGS(ap);

  
  	VPRINTK("ENTER, ap %p
  ", ap);
  
  	/* fire up the ADMA engine */

  	writew(aPIOMD4 | aGO, chan + ADMA_CONTROL);

  }

  static unsigned int adma_qc_issue(struct ata_queued_cmd *qc)

  {
  	struct adma_port_priv *pp = qc->ap->private_data;
  
  	switch (qc->tf.protocol) {
  	case ATA_PROT_DMA:
  		pp->state = adma_state_pkt;
  		adma_packet_start(qc);
  		return 0;

  	case ATAPI_PROT_DMA:

  		BUG();
  		break;
  
  	default:
  		break;
  	}
  
  	pp->state = adma_state_mmio;

  	return ata_sff_qc_issue(qc);

  }

  static inline unsigned int adma_intr_pkt(struct ata_host *host)

  {
  	unsigned int handled = 0, port_no;

  	for (port_no = 0; port_no < host->n_ports; ++port_no) {
  		struct ata_port *ap = host->ports[port_no];

  		struct adma_port_priv *pp;
  		struct ata_queued_cmd *qc;

  		void __iomem *chan = ADMA_PORT_REGS(ap);

  		u8 status = readb(chan + ADMA_STATUS);

  
  		if (status == 0)
  			continue;
  		handled = 1;
  		adma_enter_reg_mode(ap);

  		pp = ap->private_data;
  		if (!pp || pp->state != adma_state_pkt)
  			continue;

  		qc = ata_qc_from_tag(ap, ap->link.active_tag);

  		if (qc && (!(qc->tf.flags & ATA_TFLAG_POLLING))) {

  			if (status & aPERR)
  				qc->err_mask |= AC_ERR_HOST_BUS;
  			else if ((status & (aPSD | aUIRQ)))

  				qc->err_mask |= AC_ERR_OTHER;

  
  			if (pp->pkt[0] & cATERR)
  				qc->err_mask |= AC_ERR_DEV;

  			else if (pp->pkt[0] != cDONE)

  				qc->err_mask |= AC_ERR_OTHER;

  			if (!qc->err_mask)
  				ata_qc_complete(qc);
  			else {

  				struct ata_eh_info *ehi = &ap->link.eh_info;

  				ata_ehi_clear_desc(ehi);
  				ata_ehi_push_desc(ehi,
  					"ADMA-status 0x%02X", status);
  				ata_ehi_push_desc(ehi,
  					"pkt[0] 0x%02X", pp->pkt[0]);
  
  				if (qc->err_mask == AC_ERR_DEV)
  					ata_port_abort(ap);
  				else
  					ata_port_freeze(ap);
  			}

  		}

  	}
  	return handled;
  }

  static inline unsigned int adma_intr_mmio(struct ata_host *host)

  {
  	unsigned int handled = 0, port_no;

  	for (port_no = 0; port_no < host->n_ports; ++port_no) {

  		struct ata_port *ap = host->ports[port_no];
  		struct adma_port_priv *pp = ap->private_data;
  		struct ata_queued_cmd *qc;
  
  		if (!pp || pp->state != adma_state_mmio)
  			continue;
  		qc = ata_qc_from_tag(ap, ap->link.active_tag);
  		if (qc && (!(qc->tf.flags & ATA_TFLAG_POLLING))) {
  
  			/* check main status, clearing INTRQ */
  			u8 status = ata_sff_check_status(ap);
  			if ((status & ATA_BUSY))

  				continue;

  			DPRINTK("ata%u: protocol %d (dev_stat 0x%X)
  ",
  				ap->print_id, qc->tf.protocol, status);
  
  			/* complete taskfile transaction */
  			pp->state = adma_state_idle;
  			qc->err_mask |= ac_err_mask(status);
  			if (!qc->err_mask)
  				ata_qc_complete(qc);
  			else {
  				struct ata_eh_info *ehi = &ap->link.eh_info;
  				ata_ehi_clear_desc(ehi);
  				ata_ehi_push_desc(ehi, "status 0x%02X", status);
  
  				if (qc->err_mask == AC_ERR_DEV)
  					ata_port_abort(ap);
  				else
  					ata_port_freeze(ap);

  			}

  			handled = 1;

  		}
  	}
  	return handled;
  }

  static irqreturn_t adma_intr(int irq, void *dev_instance)

  {

  	struct ata_host *host = dev_instance;

  	unsigned int handled = 0;
  
  	VPRINTK("ENTER
  ");

  	spin_lock(&host->lock);
  	handled  = adma_intr_pkt(host) | adma_intr_mmio(host);
  	spin_unlock(&host->lock);

  
  	VPRINTK("EXIT
  ");
  
  	return IRQ_RETVAL(handled);
  }

  static void adma_ata_setup_port(struct ata_ioports *port, void __iomem *base)

  {
  	port->cmd_addr		=
  	port->data_addr		= base + 0x000;
  	port->error_addr	=
  	port->feature_addr	= base + 0x004;
  	port->nsect_addr	= base + 0x008;
  	port->lbal_addr		= base + 0x00c;
  	port->lbam_addr		= base + 0x010;
  	port->lbah_addr		= base + 0x014;
  	port->device_addr	= base + 0x018;
  	port->status_addr	=
  	port->command_addr	= base + 0x01c;
  	port->altstatus_addr	=
  	port->ctl_addr		= base + 0x038;
  }
  
  static int adma_port_start(struct ata_port *ap)
  {

  	struct device *dev = ap->host->dev;

  	struct adma_port_priv *pp;

  	adma_enter_reg_mode(ap);

  	pp = devm_kzalloc(dev, sizeof(*pp), GFP_KERNEL);

  	if (!pp)

  		return -ENOMEM;
  	pp->pkt = dmam_alloc_coherent(dev, ADMA_PKT_BYTES, &pp->pkt_dma,
  				      GFP_KERNEL);

  	if (!pp->pkt)

  		return -ENOMEM;

  	/* paranoia? */
  	if ((pp->pkt_dma & 7) != 0) {

  		printk(KERN_ERR "bad alignment for pp->pkt_dma: %08x
  ",

  						(u32)pp->pkt_dma);

  		return -ENOMEM;

  	}

  	ap->private_data = pp;
  	adma_reinit_engine(ap);
  	return 0;

  }
  
  static void adma_port_stop(struct ata_port *ap)
  {

  	adma_reset_engine(ap);

  }

  static void adma_host_init(struct ata_host *host, unsigned int chip_id)

  {
  	unsigned int port_no;

  
  	/* enable/lock aGO operation */

  	writeb(7, host->iomap[ADMA_MMIO_BAR] + ADMA_MODE_LOCK);

  
  	/* reset the ADMA logic */
  	for (port_no = 0; port_no < ADMA_PORTS; ++port_no)

  		adma_reset_engine(host->ports[port_no]);

  }

  static int adma_ata_init_one(struct pci_dev *pdev,

  			     const struct pci_device_id *ent)

  {

  	unsigned int board_idx = (unsigned int) ent->driver_data;

  	const struct ata_port_info *ppi[] = { &adma_port_info[board_idx], NULL };
  	struct ata_host *host;
  	void __iomem *mmio_base;

  	int rc, port_no;

  	ata_print_version_once(&pdev->dev, DRV_VERSION);

  	/* alloc host */
  	host = ata_host_alloc_pinfo(&pdev->dev, ppi, ADMA_PORTS);
  	if (!host)
  		return -ENOMEM;
  
  	/* acquire resources and fill host */

  	rc = pcim_enable_device(pdev);

  	if (rc)
  		return rc;

  	if ((pci_resource_flags(pdev, 4) & IORESOURCE_MEM) == 0)
  		return -ENODEV;

  	rc = pcim_iomap_regions(pdev, 1 << ADMA_MMIO_BAR, DRV_NAME);
  	if (rc)
  		return rc;

  	host->iomap = pcim_iomap_table(pdev);
  	mmio_base = host->iomap[ADMA_MMIO_BAR];

  	rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
  	if (rc) {
  		dev_err(&pdev->dev, "32-bit DMA enable failed
  ");

  		return rc;

  	}

  	for (port_no = 0; port_no < ADMA_PORTS; ++port_no) {
  		struct ata_port *ap = host->ports[port_no];
  		void __iomem *port_base = ADMA_ATA_REGS(mmio_base, port_no);
  		unsigned int offset = port_base - mmio_base;
  
  		adma_ata_setup_port(&ap->ioaddr, port_base);
  
  		ata_port_pbar_desc(ap, ADMA_MMIO_BAR, -1, "mmio");
  		ata_port_pbar_desc(ap, ADMA_MMIO_BAR, offset, "port");
  	}

  
  	/* initialize adapter */

  	adma_host_init(host, board_idx);

  	pci_set_master(pdev);
  	return ata_host_activate(host, pdev->irq, adma_intr, IRQF_SHARED,
  				 &adma_ata_sht);

  }

  module_pci_driver(adma_ata_pci_driver);

  
  MODULE_AUTHOR("Mark Lord");
  MODULE_DESCRIPTION("Pacific Digital Corporation ADMA low-level driver");
  MODULE_LICENSE("GPL");
  MODULE_DEVICE_TABLE(pci, adma_ata_pci_tbl);
  MODULE_VERSION(DRV_VERSION);