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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 *  sata_via.c - VIA Serial ATA controllers4 *5 *  Maintained by:  Tejun Heo <tj@kernel.org>6 * 		   Please ALWAYS copy linux-ide@vger.kernel.org7 *		   on emails.8 *9 *  Copyright 2003-2004 Red Hat, Inc.  All rights reserved.10 *  Copyright 2003-2004 Jeff Garzik11 *12 *  libata documentation is available via 'make {ps|pdf}docs',13 *  as Documentation/driver-api/libata.rst14 *15 *  Hardware documentation available under NDA.16 */17 18#include <linux/kernel.h>19#include <linux/module.h>20#include <linux/pci.h>21#include <linux/blkdev.h>22#include <linux/delay.h>23#include <linux/device.h>24#include <scsi/scsi.h>25#include <scsi/scsi_cmnd.h>26#include <scsi/scsi_host.h>27#include <linux/libata.h>28 29#define DRV_NAME	"sata_via"30#define DRV_VERSION	"2.6"31 32/*33 * vt8251 is different from other sata controllers of VIA.  It has two34 * channels, each channel has both Master and Slave slot.35 */36enum board_ids_enum {37	vt6420,38	vt6421,39	vt8251,40};41 42enum {43	SATA_CHAN_ENAB		= 0x40, /* SATA channel enable */44	SATA_INT_GATE		= 0x41, /* SATA interrupt gating */45	SATA_NATIVE_MODE	= 0x42, /* Native mode enable */46	SVIA_MISC_3		= 0x46,	/* Miscellaneous Control III */47	PATA_UDMA_TIMING	= 0xB3, /* PATA timing for DMA/ cable detect */48	PATA_PIO_TIMING		= 0xAB, /* PATA timing register */49 50	PORT0			= (1 << 1),51	PORT1			= (1 << 0),52	ALL_PORTS		= PORT0 | PORT1,53 54	NATIVE_MODE_ALL		= (1 << 7) | (1 << 6) | (1 << 5) | (1 << 4),55 56	SATA_EXT_PHY		= (1 << 6), /* 0==use PATA, 1==ext phy */57 58	SATA_HOTPLUG		= (1 << 5), /* enable IRQ on hotplug */59};60 61struct svia_priv {62	bool			wd_workaround;63};64 65static int vt6420_hotplug;66module_param_named(vt6420_hotplug, vt6420_hotplug, int, 0644);67MODULE_PARM_DESC(vt6420_hotplug, "Enable hot-plug support for VT6420 (0=Don't support, 1=support)");68 69static int svia_init_one(struct pci_dev *pdev, const struct pci_device_id *ent);70#ifdef CONFIG_PM_SLEEP71static int svia_pci_device_resume(struct pci_dev *pdev);72#endif73static int svia_scr_read(struct ata_link *link, unsigned int sc_reg, u32 *val);74static int svia_scr_write(struct ata_link *link, unsigned int sc_reg, u32 val);75static int vt8251_scr_read(struct ata_link *link, unsigned int scr, u32 *val);76static int vt8251_scr_write(struct ata_link *link, unsigned int scr, u32 val);77static void svia_tf_load(struct ata_port *ap, const struct ata_taskfile *tf);78static void svia_noop_freeze(struct ata_port *ap);79static int vt6420_prereset(struct ata_link *link, unsigned long deadline);80static void vt6420_bmdma_start(struct ata_queued_cmd *qc);81static int vt6421_pata_cable_detect(struct ata_port *ap);82static void vt6421_set_pio_mode(struct ata_port *ap, struct ata_device *adev);83static void vt6421_set_dma_mode(struct ata_port *ap, struct ata_device *adev);84static void vt6421_error_handler(struct ata_port *ap);85 86static const struct pci_device_id svia_pci_tbl[] = {87	{ PCI_VDEVICE(VIA, 0x5337), vt6420 },88	{ PCI_VDEVICE(VIA, 0x0591), vt6420 }, /* 2 sata chnls (Master) */89	{ PCI_VDEVICE(VIA, 0x3149), vt6420 }, /* 2 sata chnls (Master) */90	{ PCI_VDEVICE(VIA, 0x3249), vt6421 }, /* 2 sata chnls, 1 pata chnl */91	{ PCI_VDEVICE(VIA, 0x5372), vt6420 },92	{ PCI_VDEVICE(VIA, 0x7372), vt6420 },93	{ PCI_VDEVICE(VIA, 0x5287), vt8251 }, /* 2 sata chnls (Master/Slave) */94	{ PCI_VDEVICE(VIA, 0x9000), vt8251 },95 96	{ }	/* terminate list */97};98 99static struct pci_driver svia_pci_driver = {100	.name			= DRV_NAME,101	.id_table		= svia_pci_tbl,102	.probe			= svia_init_one,103#ifdef CONFIG_PM_SLEEP104	.suspend		= ata_pci_device_suspend,105	.resume			= svia_pci_device_resume,106#endif107	.remove			= ata_pci_remove_one,108};109 110static const struct scsi_host_template svia_sht = {111	ATA_BMDMA_SHT(DRV_NAME),112};113 114static struct ata_port_operations svia_base_ops = {115	.inherits		= &ata_bmdma_port_ops,116	.sff_tf_load		= svia_tf_load,117};118 119static struct ata_port_operations vt6420_sata_ops = {120	.inherits		= &svia_base_ops,121	.freeze			= svia_noop_freeze,122	.prereset		= vt6420_prereset,123	.bmdma_start		= vt6420_bmdma_start,124};125 126static struct ata_port_operations vt6421_pata_ops = {127	.inherits		= &svia_base_ops,128	.cable_detect		= vt6421_pata_cable_detect,129	.set_piomode		= vt6421_set_pio_mode,130	.set_dmamode		= vt6421_set_dma_mode,131};132 133static struct ata_port_operations vt6421_sata_ops = {134	.inherits		= &svia_base_ops,135	.scr_read		= svia_scr_read,136	.scr_write		= svia_scr_write,137	.error_handler		= vt6421_error_handler,138};139 140static struct ata_port_operations vt8251_ops = {141	.inherits		= &svia_base_ops,142	.hardreset		= sata_std_hardreset,143	.scr_read		= vt8251_scr_read,144	.scr_write		= vt8251_scr_write,145};146 147static const struct ata_port_info vt6420_port_info = {148	.flags		= ATA_FLAG_SATA,149	.pio_mask	= ATA_PIO4,150	.mwdma_mask	= ATA_MWDMA2,151	.udma_mask	= ATA_UDMA6,152	.port_ops	= &vt6420_sata_ops,153};154 155static const struct ata_port_info vt6421_sport_info = {156	.flags		= ATA_FLAG_SATA,157	.pio_mask	= ATA_PIO4,158	.mwdma_mask	= ATA_MWDMA2,159	.udma_mask	= ATA_UDMA6,160	.port_ops	= &vt6421_sata_ops,161};162 163static const struct ata_port_info vt6421_pport_info = {164	.flags		= ATA_FLAG_SLAVE_POSS,165	.pio_mask	= ATA_PIO4,166	/* No MWDMA */167	.udma_mask	= ATA_UDMA6,168	.port_ops	= &vt6421_pata_ops,169};170 171static const struct ata_port_info vt8251_port_info = {172	.flags		= ATA_FLAG_SATA | ATA_FLAG_SLAVE_POSS,173	.pio_mask	= ATA_PIO4,174	.mwdma_mask	= ATA_MWDMA2,175	.udma_mask	= ATA_UDMA6,176	.port_ops	= &vt8251_ops,177};178 179MODULE_AUTHOR("Jeff Garzik");180MODULE_DESCRIPTION("SCSI low-level driver for VIA SATA controllers");181MODULE_LICENSE("GPL");182MODULE_DEVICE_TABLE(pci, svia_pci_tbl);183MODULE_VERSION(DRV_VERSION);184 185static int svia_scr_read(struct ata_link *link, unsigned int sc_reg, u32 *val)186{187	if (sc_reg > SCR_CONTROL)188		return -EINVAL;189	*val = ioread32(link->ap->ioaddr.scr_addr + (4 * sc_reg));190	return 0;191}192 193static int svia_scr_write(struct ata_link *link, unsigned int sc_reg, u32 val)194{195	if (sc_reg > SCR_CONTROL)196		return -EINVAL;197	iowrite32(val, link->ap->ioaddr.scr_addr + (4 * sc_reg));198	return 0;199}200 201static int vt8251_scr_read(struct ata_link *link, unsigned int scr, u32 *val)202{203	static const u8 ipm_tbl[] = { 1, 2, 6, 0 };204	struct pci_dev *pdev = to_pci_dev(link->ap->host->dev);205	int slot = 2 * link->ap->port_no + link->pmp;206	u32 v = 0;207	u8 raw;208 209	switch (scr) {210	case SCR_STATUS:211		pci_read_config_byte(pdev, 0xA0 + slot, &raw);212 213		/* read the DET field, bit0 and 1 of the config byte */214		v |= raw & 0x03;215 216		/* read the SPD field, bit4 of the configure byte */217		if (raw & (1 << 4))218			v |= 0x02 << 4;219		else220			v |= 0x01 << 4;221 222		/* read the IPM field, bit2 and 3 of the config byte */223		v |= ipm_tbl[(raw >> 2) & 0x3];224		break;225 226	case SCR_ERROR:227		/* devices other than 5287 uses 0xA8 as base */228		WARN_ON(pdev->device != 0x5287);229		pci_read_config_dword(pdev, 0xB0 + slot * 4, &v);230		break;231 232	case SCR_CONTROL:233		pci_read_config_byte(pdev, 0xA4 + slot, &raw);234 235		/* read the DET field, bit0 and bit1 */236		v |= ((raw & 0x02) << 1) | (raw & 0x01);237 238		/* read the IPM field, bit2 and bit3 */239		v |= ((raw >> 2) & 0x03) << 8;240		break;241 242	default:243		return -EINVAL;244	}245 246	*val = v;247	return 0;248}249 250static int vt8251_scr_write(struct ata_link *link, unsigned int scr, u32 val)251{252	struct pci_dev *pdev = to_pci_dev(link->ap->host->dev);253	int slot = 2 * link->ap->port_no + link->pmp;254	u32 v = 0;255 256	switch (scr) {257	case SCR_ERROR:258		/* devices other than 5287 uses 0xA8 as base */259		WARN_ON(pdev->device != 0x5287);260		pci_write_config_dword(pdev, 0xB0 + slot * 4, val);261		return 0;262 263	case SCR_CONTROL:264		/* set the DET field */265		v |= ((val & 0x4) >> 1) | (val & 0x1);266 267		/* set the IPM field */268		v |= ((val >> 8) & 0x3) << 2;269 270		pci_write_config_byte(pdev, 0xA4 + slot, v);271		return 0;272 273	default:274		return -EINVAL;275	}276}277 278/**279 *	svia_tf_load - send taskfile registers to host controller280 *	@ap: Port to which output is sent281 *	@tf: ATA taskfile register set282 *283 *	Outputs ATA taskfile to standard ATA host controller.284 *285 *	This is to fix the internal bug of via chipsets, which will286 *	reset the device register after changing the IEN bit on ctl287 *	register.288 */289static void svia_tf_load(struct ata_port *ap, const struct ata_taskfile *tf)290{291	struct ata_taskfile ttf;292 293	if (tf->ctl != ap->last_ctl)  {294		ttf = *tf;295		ttf.flags |= ATA_TFLAG_DEVICE;296		tf = &ttf;297	}298	ata_sff_tf_load(ap, tf);299}300 301static void svia_noop_freeze(struct ata_port *ap)302{303	/* Some VIA controllers choke if ATA_NIEN is manipulated in304	 * certain way.  Leave it alone and just clear pending IRQ.305	 */306	ap->ops->sff_check_status(ap);307	ata_bmdma_irq_clear(ap);308}309 310/**311 *	vt6420_prereset - prereset for vt6420312 *	@link: target ATA link313 *	@deadline: deadline jiffies for the operation314 *315 *	SCR registers on vt6420 are pieces of shit and may hang the316 *	whole machine completely if accessed with the wrong timing.317 *	To avoid such catastrophe, vt6420 doesn't provide generic SCR318 *	access operations, but uses SStatus and SControl only during319 *	boot probing in controlled way.320 *321 *	As the old (pre EH update) probing code is proven to work, we322 *	strictly follow the access pattern.323 *324 *	LOCKING:325 *	Kernel thread context (may sleep)326 *327 *	RETURNS:328 *	0 on success, -errno otherwise.329 */330static int vt6420_prereset(struct ata_link *link, unsigned long deadline)331{332	struct ata_port *ap = link->ap;333	struct ata_eh_context *ehc = &ap->link.eh_context;334	unsigned long timeout = jiffies + (HZ * 5);335	u32 sstatus, scontrol;336	int online;337 338	/* don't do any SCR stuff if we're not loading */339	if (!(ap->pflags & ATA_PFLAG_LOADING))340		goto skip_scr;341 342	/* Resume phy.  This is the old SATA resume sequence */343	svia_scr_write(link, SCR_CONTROL, 0x300);344	svia_scr_read(link, SCR_CONTROL, &scontrol); /* flush */345 346	/* wait for phy to become ready, if necessary */347	do {348		ata_msleep(link->ap, 200);349		svia_scr_read(link, SCR_STATUS, &sstatus);350		if ((sstatus & 0xf) != 1)351			break;352	} while (time_before(jiffies, timeout));353 354	/* open code sata_print_link_status() */355	svia_scr_read(link, SCR_STATUS, &sstatus);356	svia_scr_read(link, SCR_CONTROL, &scontrol);357 358	online = (sstatus & 0xf) == 0x3;359 360	ata_port_info(ap,361		      "SATA link %s 1.5 Gbps (SStatus %X SControl %X)\n",362		      online ? "up" : "down", sstatus, scontrol);363 364	/* SStatus is read one more time */365	svia_scr_read(link, SCR_STATUS, &sstatus);366 367	if (!online) {368		/* tell EH to bail */369		ehc->i.action &= ~ATA_EH_RESET;370		return 0;371	}372 373 skip_scr:374	/* wait for !BSY */375	ata_sff_wait_ready(link, deadline);376 377	return 0;378}379 380static void vt6420_bmdma_start(struct ata_queued_cmd *qc)381{382	struct ata_port *ap = qc->ap;383	if ((qc->tf.command == ATA_CMD_PACKET) &&384	    (qc->scsicmd->sc_data_direction == DMA_TO_DEVICE)) {385		/* Prevents corruption on some ATAPI burners */386		ata_sff_pause(ap);387	}388	ata_bmdma_start(qc);389}390 391static int vt6421_pata_cable_detect(struct ata_port *ap)392{393	struct pci_dev *pdev = to_pci_dev(ap->host->dev);394	u8 tmp;395 396	pci_read_config_byte(pdev, PATA_UDMA_TIMING, &tmp);397	if (tmp & 0x10)398		return ATA_CBL_PATA40;399	return ATA_CBL_PATA80;400}401 402static void vt6421_set_pio_mode(struct ata_port *ap, struct ata_device *adev)403{404	struct pci_dev *pdev = to_pci_dev(ap->host->dev);405	static const u8 pio_bits[] = { 0xA8, 0x65, 0x65, 0x31, 0x20 };406	pci_write_config_byte(pdev, PATA_PIO_TIMING - adev->devno,407			      pio_bits[adev->pio_mode - XFER_PIO_0]);408}409 410static void vt6421_set_dma_mode(struct ata_port *ap, struct ata_device *adev)411{412	struct pci_dev *pdev = to_pci_dev(ap->host->dev);413	static const u8 udma_bits[] = { 0xEE, 0xE8, 0xE6, 0xE4, 0xE2, 0xE1, 0xE0, 0xE0 };414	pci_write_config_byte(pdev, PATA_UDMA_TIMING - adev->devno,415			      udma_bits[adev->dma_mode - XFER_UDMA_0]);416}417 418static const unsigned int svia_bar_sizes[] = {419	8, 4, 8, 4, 16, 256420};421 422static const unsigned int vt6421_bar_sizes[] = {423	16, 16, 16, 16, 32, 128424};425 426static void __iomem *svia_scr_addr(void __iomem *addr, unsigned int port)427{428	return addr + (port * 128);429}430 431static void __iomem *vt6421_scr_addr(void __iomem *addr, unsigned int port)432{433	return addr + (port * 64);434}435 436static void vt6421_init_addrs(struct ata_port *ap)437{438	void __iomem * const * iomap = ap->host->iomap;439	void __iomem *reg_addr = iomap[ap->port_no];440	void __iomem *bmdma_addr = iomap[4] + (ap->port_no * 8);441	struct ata_ioports *ioaddr = &ap->ioaddr;442 443	ioaddr->cmd_addr = reg_addr;444	ioaddr->altstatus_addr =445	ioaddr->ctl_addr = (void __iomem *)446		((unsigned long)(reg_addr + 8) | ATA_PCI_CTL_OFS);447	ioaddr->bmdma_addr = bmdma_addr;448	ioaddr->scr_addr = vt6421_scr_addr(iomap[5], ap->port_no);449 450	ata_sff_std_ports(ioaddr);451 452	ata_port_pbar_desc(ap, ap->port_no, -1, "port");453	ata_port_pbar_desc(ap, 4, ap->port_no * 8, "bmdma");454}455 456static int vt6420_prepare_host(struct pci_dev *pdev, struct ata_host **r_host)457{458	const struct ata_port_info *ppi[] = { &vt6420_port_info, NULL };459	struct ata_host *host;460	int rc;461 462	if (vt6420_hotplug) {463		ppi[0]->port_ops->scr_read = svia_scr_read;464		ppi[0]->port_ops->scr_write = svia_scr_write;465	}466 467	rc = ata_pci_bmdma_prepare_host(pdev, ppi, &host);468	if (rc)469		return rc;470	*r_host = host;471 472	rc = pcim_iomap_regions(pdev, 1 << 5, DRV_NAME);473	if (rc) {474		dev_err(&pdev->dev, "failed to iomap PCI BAR 5\n");475		return rc;476	}477 478	host->ports[0]->ioaddr.scr_addr = svia_scr_addr(host->iomap[5], 0);479	host->ports[1]->ioaddr.scr_addr = svia_scr_addr(host->iomap[5], 1);480 481	return 0;482}483 484static int vt6421_prepare_host(struct pci_dev *pdev, struct ata_host **r_host)485{486	const struct ata_port_info *ppi[] =487		{ &vt6421_sport_info, &vt6421_sport_info, &vt6421_pport_info };488	struct ata_host *host;489	int i, rc;490 491	*r_host = host = ata_host_alloc_pinfo(&pdev->dev, ppi, ARRAY_SIZE(ppi));492	if (!host) {493		dev_err(&pdev->dev, "failed to allocate host\n");494		return -ENOMEM;495	}496 497	rc = pcim_iomap_regions(pdev, 0x3f, DRV_NAME);498	if (rc) {499		dev_err(&pdev->dev, "failed to request/iomap PCI BARs (errno=%d)\n",500			rc);501		return rc;502	}503	host->iomap = pcim_iomap_table(pdev);504 505	for (i = 0; i < host->n_ports; i++)506		vt6421_init_addrs(host->ports[i]);507 508	return dma_set_mask_and_coherent(&pdev->dev, ATA_DMA_MASK);509}510 511static int vt8251_prepare_host(struct pci_dev *pdev, struct ata_host **r_host)512{513	const struct ata_port_info *ppi[] = { &vt8251_port_info, NULL };514	struct ata_host *host;515	int i, rc;516 517	rc = ata_pci_bmdma_prepare_host(pdev, ppi, &host);518	if (rc)519		return rc;520	*r_host = host;521 522	rc = pcim_iomap_regions(pdev, 1 << 5, DRV_NAME);523	if (rc) {524		dev_err(&pdev->dev, "failed to iomap PCI BAR 5\n");525		return rc;526	}527 528	/* 8251 hosts four sata ports as M/S of the two channels */529	for (i = 0; i < host->n_ports; i++)530		ata_slave_link_init(host->ports[i]);531 532	return 0;533}534 535static void svia_wd_fix(struct pci_dev *pdev)536{537	u8 tmp8;538 539	pci_read_config_byte(pdev, 0x52, &tmp8);540	pci_write_config_byte(pdev, 0x52, tmp8 | BIT(2));541}542 543static irqreturn_t vt642x_interrupt(int irq, void *dev_instance)544{545	struct ata_host *host = dev_instance;546	irqreturn_t rc = ata_bmdma_interrupt(irq, dev_instance);547 548	/* if the IRQ was not handled, it might be a hotplug IRQ */549	if (rc != IRQ_HANDLED) {550		u32 serror;551		unsigned long flags;552 553		spin_lock_irqsave(&host->lock, flags);554		/* check for hotplug on port 0 */555		svia_scr_read(&host->ports[0]->link, SCR_ERROR, &serror);556		if (serror & SERR_PHYRDY_CHG) {557			ata_ehi_hotplugged(&host->ports[0]->link.eh_info);558			ata_port_freeze(host->ports[0]);559			rc = IRQ_HANDLED;560		}561		/* check for hotplug on port 1 */562		svia_scr_read(&host->ports[1]->link, SCR_ERROR, &serror);563		if (serror & SERR_PHYRDY_CHG) {564			ata_ehi_hotplugged(&host->ports[1]->link.eh_info);565			ata_port_freeze(host->ports[1]);566			rc = IRQ_HANDLED;567		}568		spin_unlock_irqrestore(&host->lock, flags);569	}570 571	return rc;572}573 574static void vt6421_error_handler(struct ata_port *ap)575{576	struct svia_priv *hpriv = ap->host->private_data;577	struct pci_dev *pdev = to_pci_dev(ap->host->dev);578	u32 serror;579 580	/* see svia_configure() for description */581	if (!hpriv->wd_workaround) {582		svia_scr_read(&ap->link, SCR_ERROR, &serror);583		if (serror == 0x1000500) {584			ata_port_warn(ap, "Incompatible drive: enabling workaround. This slows down transfer rate to ~60 MB/s");585			svia_wd_fix(pdev);586			hpriv->wd_workaround = true;587			ap->link.eh_context.i.flags |= ATA_EHI_QUIET;588		}589	}590 591	ata_sff_error_handler(ap);592}593 594static void svia_configure(struct pci_dev *pdev, int board_id,595			   struct svia_priv *hpriv)596{597	u8 tmp8;598 599	pci_read_config_byte(pdev, PCI_INTERRUPT_LINE, &tmp8);600	dev_info(&pdev->dev, "routed to hard irq line %d\n",601		 (int) (tmp8 & 0xf0) == 0xf0 ? 0 : tmp8 & 0x0f);602 603	/* make sure SATA channels are enabled */604	pci_read_config_byte(pdev, SATA_CHAN_ENAB, &tmp8);605	if ((tmp8 & ALL_PORTS) != ALL_PORTS) {606		dev_dbg(&pdev->dev, "enabling SATA channels (0x%x)\n",607			(int)tmp8);608		tmp8 |= ALL_PORTS;609		pci_write_config_byte(pdev, SATA_CHAN_ENAB, tmp8);610	}611 612	/* make sure interrupts for each channel sent to us */613	pci_read_config_byte(pdev, SATA_INT_GATE, &tmp8);614	if ((tmp8 & ALL_PORTS) != ALL_PORTS) {615		dev_dbg(&pdev->dev, "enabling SATA channel interrupts (0x%x)\n",616			(int) tmp8);617		tmp8 |= ALL_PORTS;618		pci_write_config_byte(pdev, SATA_INT_GATE, tmp8);619	}620 621	/* make sure native mode is enabled */622	pci_read_config_byte(pdev, SATA_NATIVE_MODE, &tmp8);623	if ((tmp8 & NATIVE_MODE_ALL) != NATIVE_MODE_ALL) {624		dev_dbg(&pdev->dev,625			"enabling SATA channel native mode (0x%x)\n",626			(int) tmp8);627		tmp8 |= NATIVE_MODE_ALL;628		pci_write_config_byte(pdev, SATA_NATIVE_MODE, tmp8);629	}630 631	if ((board_id == vt6420 && vt6420_hotplug) || board_id == vt6421) {632		/* enable IRQ on hotplug */633		pci_read_config_byte(pdev, SVIA_MISC_3, &tmp8);634		if ((tmp8 & SATA_HOTPLUG) != SATA_HOTPLUG) {635			dev_dbg(&pdev->dev,636				"enabling SATA hotplug (0x%x)\n",637				(int) tmp8);638			tmp8 |= SATA_HOTPLUG;639			pci_write_config_byte(pdev, SVIA_MISC_3, tmp8);640		}641	}642 643	/*644	 * vt6420/1 has problems talking to some drives.  The following645	 * is the fix from Joseph Chan <JosephChan@via.com.tw>.646	 *647	 * When host issues HOLD, device may send up to 20DW of data648	 * before acknowledging it with HOLDA and the host should be649	 * able to buffer them in FIFO.  Unfortunately, some WD drives650	 * send up to 40DW before acknowledging HOLD and, in the651	 * default configuration, this ends up overflowing vt6421's652	 * FIFO, making the controller abort the transaction with653	 * R_ERR.654	 *655	 * Rx52[2] is the internal 128DW FIFO Flow control watermark656	 * adjusting mechanism enable bit and the default value 0657	 * means host will issue HOLD to device when the left FIFO658	 * size goes below 32DW.  Setting it to 1 makes the watermark659	 * 64DW.660	 *661	 * https://bugzilla.kernel.org/show_bug.cgi?id=15173662	 * http://article.gmane.org/gmane.linux.ide/46352663	 * http://thread.gmane.org/gmane.linux.kernel/1062139664	 *665	 * As the fix slows down data transfer, apply it only if the error666	 * actually appears - see vt6421_error_handler()667	 * Apply the fix always on vt6420 as we don't know if SCR_ERROR can be668	 * read safely.669	 */670	if (board_id == vt6420) {671		svia_wd_fix(pdev);672		hpriv->wd_workaround = true;673	}674}675 676static int svia_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)677{678	unsigned int i;679	int rc;680	struct ata_host *host = NULL;681	int board_id = (int) ent->driver_data;682	const unsigned *bar_sizes;683	struct svia_priv *hpriv;684 685	ata_print_version_once(&pdev->dev, DRV_VERSION);686 687	rc = pcim_enable_device(pdev);688	if (rc)689		return rc;690 691	if (board_id == vt6421)692		bar_sizes = &vt6421_bar_sizes[0];693	else694		bar_sizes = &svia_bar_sizes[0];695 696	for (i = 0; i < ARRAY_SIZE(svia_bar_sizes); i++)697		if ((pci_resource_start(pdev, i) == 0) ||698		    (pci_resource_len(pdev, i) < bar_sizes[i])) {699			dev_err(&pdev->dev,700				"invalid PCI BAR %u (sz 0x%llx, val 0x%llx)\n",701				i,702				(unsigned long long)pci_resource_start(pdev, i),703				(unsigned long long)pci_resource_len(pdev, i));704			return -ENODEV;705		}706 707	switch (board_id) {708	case vt6420:709		rc = vt6420_prepare_host(pdev, &host);710		break;711	case vt6421:712		rc = vt6421_prepare_host(pdev, &host);713		break;714	case vt8251:715		rc = vt8251_prepare_host(pdev, &host);716		break;717	default:718		rc = -EINVAL;719	}720	if (rc)721		return rc;722 723	hpriv = devm_kzalloc(&pdev->dev, sizeof(*hpriv), GFP_KERNEL);724	if (!hpriv)725		return -ENOMEM;726	host->private_data = hpriv;727 728	svia_configure(pdev, board_id, hpriv);729 730	pci_set_master(pdev);731	if ((board_id == vt6420 && vt6420_hotplug) || board_id == vt6421)732		return ata_host_activate(host, pdev->irq, vt642x_interrupt,733					 IRQF_SHARED, &svia_sht);734	else735		return ata_host_activate(host, pdev->irq, ata_bmdma_interrupt,736					 IRQF_SHARED, &svia_sht);737}738 739#ifdef CONFIG_PM_SLEEP740static int svia_pci_device_resume(struct pci_dev *pdev)741{742	struct ata_host *host = pci_get_drvdata(pdev);743	struct svia_priv *hpriv = host->private_data;744	int rc;745 746	rc = ata_pci_device_do_resume(pdev);747	if (rc)748		return rc;749 750	if (hpriv->wd_workaround)751		svia_wd_fix(pdev);752	ata_host_resume(host);753 754	return 0;755}756#endif757 758module_pci_driver(svia_pci_driver);759