drivers/ata/sata_via.c

   1 /*
   2  *  sata_via.c - VIA Serial ATA controllers
   3  *
   4  *  Maintained by:  Tejun Heo <tj@kernel.org>
   5  *                 Please ALWAYS copy linux-ide@vger.kernel.org
   6  *                 on emails.
   7  *
   8  *  Copyright 2003-2004 Red Hat, Inc.  All rights reserved.
   9  *  Copyright 2003-2004 Jeff Garzik
  10  *
  11  *
  12  *  This program is free software; you can redistribute it and/or modify
  13  *  it under the terms of the GNU General Public License as published by
  14  *  the Free Software Foundation; either version 2, or (at your option)
  15  *  any later version.
  16  *
  17  *  This program is distributed in the hope that it will be useful,
  18  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  *  GNU General Public License for more details.
  21  *
  22  *  You should have received a copy of the GNU General Public License
  23  *  along with this program; see the file COPYING.  If not, write to
  24  *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  25  *
  26  *
  27  *  libata documentation is available via 'make {ps|pdf}docs',
  28  *  as Documentation/DocBook/libata.*
  29  *
  30  *  Hardware documentation available under NDA.
  31  *
  32  *
  33  *
  34  */
  35
  36 #include <linux/kernel.h>
  37 #include <linux/module.h>
  38 #include <linux/pci.h>
  39 #include <linux/init.h>
  40 #include <linux/blkdev.h>
  41 #include <linux/delay.h>
  42 #include <linux/device.h>
  43 #include <scsi/scsi.h>
  44 #include <scsi/scsi_cmnd.h>
  45 #include <scsi/scsi_host.h>
  46 #include <linux/libata.h>
  47
  48 #define DRV_NAME        "sata_via"
  49 #define DRV_VERSION     "2.6"
  50
  51 /*
  52  * vt8251 is different from other sata controllers of VIA.  It has two
  53  * channels, each channel has both Master and Slave slot.
  54  */
  55 enum board_ids_enum {
  56         vt6420,
  57         vt6421,
  58         vt8251,
  59 };
  60
  61 enum {
  62         SATA_CHAN_ENAB          = 0x40, /* SATA channel enable */
  63         SATA_INT_GATE           = 0x41, /* SATA interrupt gating */
  64         SATA_NATIVE_MODE        = 0x42, /* Native mode enable */
  65         PATA_UDMA_TIMING        = 0xB3, /* PATA timing for DMA/ cable detect */
  66         PATA_PIO_TIMING         = 0xAB, /* PATA timing register */
  67
  68         PORT0                   = (1 << 1),
  69         PORT1                   = (1 << 0),
  70         ALL_PORTS               = PORT0 | PORT1,
  71
  72         NATIVE_MODE_ALL         = (1 << 7) | (1 << 6) | (1 << 5) | (1 << 4),
  73
  74         SATA_EXT_PHY            = (1 << 6), /* 0==use PATA, 1==ext phy */
  75 };
  76
  77 static int svia_init_one(struct pci_dev *pdev, const struct pci_device_id *ent);
  78 static int svia_scr_read(struct ata_link *link, unsigned int sc_reg, u32 *val);
  79 static int svia_scr_write(struct ata_link *link, unsigned int sc_reg, u32 val);
  80 static int vt8251_scr_read(struct ata_link *link, unsigned int scr, u32 *val);
  81 static int vt8251_scr_write(struct ata_link *link, unsigned int scr, u32 val);
  82 static void svia_tf_load(struct ata_port *ap, const struct ata_taskfile *tf);
  83 static void svia_noop_freeze(struct ata_port *ap);
  84 static int vt6420_prereset(struct ata_link *link, unsigned long deadline);
  85 static void vt6420_bmdma_start(struct ata_queued_cmd *qc);
  86 static int vt6421_pata_cable_detect(struct ata_port *ap);
  87 static void vt6421_set_pio_mode(struct ata_port *ap, struct ata_device *adev);
  88 static void vt6421_set_dma_mode(struct ata_port *ap, struct ata_device *adev);
  89
  90 static const struct pci_device_id svia_pci_tbl[] = {
  91         { PCI_VDEVICE(VIA, 0x5337), vt6420 },
  92         { PCI_VDEVICE(VIA, 0x0591), vt6420 }, /* 2 sata chnls (Master) */
  93         { PCI_VDEVICE(VIA, 0x3149), vt6420 }, /* 2 sata chnls (Master) */
  94         { PCI_VDEVICE(VIA, 0x3249), vt6421 }, /* 2 sata chnls, 1 pata chnl */
  95         { PCI_VDEVICE(VIA, 0x5372), vt6420 },
  96         { PCI_VDEVICE(VIA, 0x7372), vt6420 },
  97         { PCI_VDEVICE(VIA, 0x5287), vt8251 }, /* 2 sata chnls (Master/Slave) */
  98         { PCI_VDEVICE(VIA, 0x9000), vt8251 },
  99
 100         { }     /* terminate list */
 101 };
 102
 103 static struct pci_driver svia_pci_driver = {
 104         .name                   = DRV_NAME,
 105         .id_table               = svia_pci_tbl,
 106         .probe                  = svia_init_one,
 107 #ifdef CONFIG_PM
 108         .suspend                = ata_pci_device_suspend,
 109         .resume                 = ata_pci_device_resume,
 110 #endif
 111         .remove                 = ata_pci_remove_one,
 112 };
 113
 114 static struct scsi_host_template svia_sht = {
 115         ATA_BMDMA_SHT(DRV_NAME),
 116 };
 117
 118 static struct ata_port_operations svia_base_ops = {
 119         .inherits               = &ata_bmdma_port_ops,
 120         .sff_tf_load            = svia_tf_load,
 121 };
 122
 123 static struct ata_port_operations vt6420_sata_ops = {
 124         .inherits               = &svia_base_ops,
 125         .freeze                 = svia_noop_freeze,
 126         .prereset               = vt6420_prereset,
 127         .bmdma_start            = vt6420_bmdma_start,
 128 };
 129
 130 static struct ata_port_operations vt6421_pata_ops = {
 131         .inherits               = &svia_base_ops,
 132         .cable_detect           = vt6421_pata_cable_detect,
 133         .set_piomode            = vt6421_set_pio_mode,
 134         .set_dmamode            = vt6421_set_dma_mode,
 135 };
 136
 137 static struct ata_port_operations vt6421_sata_ops = {
 138         .inherits               = &svia_base_ops,
 139         .scr_read               = svia_scr_read,
 140         .scr_write              = svia_scr_write,
 141 };
 142
 143 static struct ata_port_operations vt8251_ops = {
 144         .inherits               = &svia_base_ops,
 145         .hardreset              = sata_std_hardreset,
 146         .scr_read               = vt8251_scr_read,
 147         .scr_write              = vt8251_scr_write,
 148 };
 149
 150 static const struct ata_port_info vt6420_port_info = {
 151         .flags          = ATA_FLAG_SATA,
 152         .pio_mask       = ATA_PIO4,
 153         .mwdma_mask     = ATA_MWDMA2,
 154         .udma_mask      = ATA_UDMA6,
 155         .port_ops       = &vt6420_sata_ops,
 156 };
 157
 158 static struct ata_port_info vt6421_sport_info = {
 159         .flags          = ATA_FLAG_SATA,
 160         .pio_mask       = ATA_PIO4,
 161         .mwdma_mask     = ATA_MWDMA2,
 162         .udma_mask      = ATA_UDMA6,
 163         .port_ops       = &vt6421_sata_ops,
 164 };
 165
 166 static struct ata_port_info vt6421_pport_info = {
 167         .flags          = ATA_FLAG_SLAVE_POSS,
 168         .pio_mask       = ATA_PIO4,
 169         /* No MWDMA */
 170         .udma_mask      = ATA_UDMA6,
 171         .port_ops       = &vt6421_pata_ops,
 172 };
 173
 174 static struct ata_port_info vt8251_port_info = {
 175         .flags          = ATA_FLAG_SATA | ATA_FLAG_SLAVE_POSS,
 176         .pio_mask       = ATA_PIO4,
 177         .mwdma_mask     = ATA_MWDMA2,
 178         .udma_mask      = ATA_UDMA6,
 179         .port_ops       = &vt8251_ops,
 180 };
 181
 182 MODULE_AUTHOR("Jeff Garzik");
 183 MODULE_DESCRIPTION("SCSI low-level driver for VIA SATA controllers");
 184 MODULE_LICENSE("GPL");
 185 MODULE_DEVICE_TABLE(pci, svia_pci_tbl);
 186 MODULE_VERSION(DRV_VERSION);
 187
 188 static int svia_scr_read(struct ata_link *link, unsigned int sc_reg, u32 *val)
 189 {
 190         if (sc_reg > SCR_CONTROL)
 191                 return -EINVAL;
 192         *val = ioread32(link->ap->ioaddr.scr_addr + (4 * sc_reg));
 193         return 0;
 194 }
 195
 196 static int svia_scr_write(struct ata_link *link, unsigned int sc_reg, u32 val)
 197 {
 198         if (sc_reg > SCR_CONTROL)
 199                 return -EINVAL;
 200         iowrite32(val, link->ap->ioaddr.scr_addr + (4 * sc_reg));
 201         return 0;
 202 }
 203
 204 static int vt8251_scr_read(struct ata_link *link, unsigned int scr, u32 *val)
 205 {
 206         static const u8 ipm_tbl[] = { 1, 2, 6, 0 };
 207         struct pci_dev *pdev = to_pci_dev(link->ap->host->dev);
 208         int slot = 2 * link->ap->port_no + link->pmp;
 209         u32 v = 0;
 210         u8 raw;
 211
 212         switch (scr) {
 213         case SCR_STATUS:
 214                 pci_read_config_byte(pdev, 0xA0 + slot, &raw);
 215
 216                 /* read the DET field, bit0 and 1 of the config byte */
 217                 v |= raw & 0x03;
 218
 219                 /* read the SPD field, bit4 of the configure byte */
 220                 if (raw & (1 << 4))
 221                         v |= 0x02 << 4;
 222                 else
 223                         v |= 0x01 << 4;
 224
 225                 /* read the IPM field, bit2 and 3 of the config byte */
 226                 v |= ipm_tbl[(raw >> 2) & 0x3];
 227                 break;
 228
 229         case SCR_ERROR:
 230                 /* devices other than 5287 uses 0xA8 as base */
 231                 WARN_ON(pdev->device != 0x5287);
 232                 pci_read_config_dword(pdev, 0xB0 + slot * 4, &v);
 233                 break;
 234
 235         case SCR_CONTROL:
 236                 pci_read_config_byte(pdev, 0xA4 + slot, &raw);
 237
 238                 /* read the DET field, bit0 and bit1 */
 239                 v |= ((raw & 0x02) << 1) | (raw & 0x01);
 240
 241                 /* read the IPM field, bit2 and bit3 */
 242                 v |= ((raw >> 2) & 0x03) << 8;
 243                 break;
 244
 245         default:
 246                 return -EINVAL;
 247         }
 248
 249         *val = v;
 250         return 0;
 251 }
 252
 253 static int vt8251_scr_write(struct ata_link *link, unsigned int scr, u32 val)
 254 {
 255         struct pci_dev *pdev = to_pci_dev(link->ap->host->dev);
 256         int slot = 2 * link->ap->port_no + link->pmp;
 257         u32 v = 0;
 258
 259         switch (scr) {
 260         case SCR_ERROR:
 261                 /* devices other than 5287 uses 0xA8 as base */
 262                 WARN_ON(pdev->device != 0x5287);
 263                 pci_write_config_dword(pdev, 0xB0 + slot * 4, val);
 264                 return 0;
 265
 266         case SCR_CONTROL:
 267                 /* set the DET field */
 268                 v |= ((val & 0x4) >> 1) | (val & 0x1);
 269
 270                 /* set the IPM field */
 271                 v |= ((val >> 8) & 0x3) << 2;
 272
 273                 pci_write_config_byte(pdev, 0xA4 + slot, v);
 274                 return 0;
 275
 276         default:
 277                 return -EINVAL;
 278         }
 279 }
 280
 281 /**
 282  *      svia_tf_load - send taskfile registers to host controller
 283  *      @ap: Port to which output is sent
 284  *      @tf: ATA taskfile register set
 285  *
 286  *      Outputs ATA taskfile to standard ATA host controller.
 287  *
 288  *      This is to fix the internal bug of via chipsets, which will
 289  *      reset the device register after changing the IEN bit on ctl
 290  *      register.
 291  */
 292 static void svia_tf_load(struct ata_port *ap, const struct ata_taskfile *tf)
 293 {
 294         struct ata_taskfile ttf;
 295
 296         if (tf->ctl != ap->last_ctl)  {
 297                 ttf = *tf;
 298                 ttf.flags |= ATA_TFLAG_DEVICE;
 299                 tf = &ttf;
 300         }
 301         ata_sff_tf_load(ap, tf);
 302 }
 303
 304 static void svia_noop_freeze(struct ata_port *ap)
 305 {
 306         /* Some VIA controllers choke if ATA_NIEN is manipulated in
 307          * certain way.  Leave it alone and just clear pending IRQ.
 308          */
 309         ap->ops->sff_check_status(ap);
 310         ata_bmdma_irq_clear(ap);
 311 }
 312
 313 /**
 314  *      vt6420_prereset - prereset for vt6420
 315  *      @link: target ATA link
 316  *      @deadline: deadline jiffies for the operation
 317  *
 318  *      SCR registers on vt6420 are pieces of shit and may hang the
 319  *      whole machine completely if accessed with the wrong timing.
 320  *      To avoid such catastrophe, vt6420 doesn't provide generic SCR
 321  *      access operations, but uses SStatus and SControl only during
 322  *      boot probing in controlled way.
 323  *
 324  *      As the old (pre EH update) probing code is proven to work, we
 325  *      strictly follow the access pattern.
 326  *
 327  *      LOCKING:
 328  *      Kernel thread context (may sleep)
 329  *
 330  *      RETURNS:
 331  *      0 on success, -errno otherwise.
 332  */
 333 static int vt6420_prereset(struct ata_link *link, unsigned long deadline)
 334 {
 335         struct ata_port *ap = link->ap;
 336         struct ata_eh_context *ehc = &ap->link.eh_context;
 337         unsigned long timeout = jiffies + (HZ * 5);
 338         u32 sstatus, scontrol;
 339         int online;
 340
 341         /* don't do any SCR stuff if we're not loading */
 342         if (!(ap->pflags & ATA_PFLAG_LOADING))
 343                 goto skip_scr;
 344
 345         /* Resume phy.  This is the old SATA resume sequence */
 346         svia_scr_write(link, SCR_CONTROL, 0x300);
 347         svia_scr_read(link, SCR_CONTROL, &scontrol); /* flush */
 348
 349         /* wait for phy to become ready, if necessary */
 350         do {
 351                 ata_msleep(link->ap, 200);
 352                 svia_scr_read(link, SCR_STATUS, &sstatus);
 353                 if ((sstatus & 0xf) != 1)
 354                         break;
 355         } while (time_before(jiffies, timeout));
 356
 357         /* open code sata_print_link_status() */
 358         svia_scr_read(link, SCR_STATUS, &sstatus);
 359         svia_scr_read(link, SCR_CONTROL, &scontrol);
 360
 361         online = (sstatus & 0xf) == 0x3;
 362
 363         ata_port_info(ap,
 364                       "SATA link %s 1.5 Gbps (SStatus %X SControl %X)\n",
 365                       online ? "up" : "down", sstatus, scontrol);
 366
 367         /* SStatus is read one more time */
 368         svia_scr_read(link, SCR_STATUS, &sstatus);
 369
 370         if (!online) {
 371                 /* tell EH to bail */
 372                 ehc->i.action &= ~ATA_EH_RESET;
 373                 return 0;
 374         }
 375
 376  skip_scr:
 377         /* wait for !BSY */
 378         ata_sff_wait_ready(link, deadline);
 379
 380         return 0;
 381 }
 382
 383 static void vt6420_bmdma_start(struct ata_queued_cmd *qc)
 384 {
 385         struct ata_port *ap = qc->ap;
 386         if ((qc->tf.command == ATA_CMD_PACKET) &&
 387             (qc->scsicmd->sc_data_direction == DMA_TO_DEVICE)) {
 388                 /* Prevents corruption on some ATAPI burners */
 389                 ata_sff_pause(ap);
 390         }
 391         ata_bmdma_start(qc);
 392 }
 393
 394 static int vt6421_pata_cable_detect(struct ata_port *ap)
 395 {
 396         struct pci_dev *pdev = to_pci_dev(ap->host->dev);
 397         u8 tmp;
 398
 399         pci_read_config_byte(pdev, PATA_UDMA_TIMING, &tmp);
 400         if (tmp & 0x10)
 401                 return ATA_CBL_PATA40;
 402         return ATA_CBL_PATA80;
 403 }
 404
 405 static void vt6421_set_pio_mode(struct ata_port *ap, struct ata_device *adev)
 406 {
 407         struct pci_dev *pdev = to_pci_dev(ap->host->dev);
 408         static const u8 pio_bits[] = { 0xA8, 0x65, 0x65, 0x31, 0x20 };
 409         pci_write_config_byte(pdev, PATA_PIO_TIMING - adev->devno,
 410                               pio_bits[adev->pio_mode - XFER_PIO_0]);
 411 }
 412
 413 static void vt6421_set_dma_mode(struct ata_port *ap, struct ata_device *adev)
 414 {
 415         struct pci_dev *pdev = to_pci_dev(ap->host->dev);
 416         static const u8 udma_bits[] = { 0xEE, 0xE8, 0xE6, 0xE4, 0xE2, 0xE1, 0xE0, 0xE0 };
 417         pci_write_config_byte(pdev, PATA_UDMA_TIMING - adev->devno,
 418                               udma_bits[adev->dma_mode - XFER_UDMA_0]);
 419 }
 420
 421 static const unsigned int svia_bar_sizes[] = {
 422         8, 4, 8, 4, 16, 256
 423 };
 424
 425 static const unsigned int vt6421_bar_sizes[] = {
 426         16, 16, 16, 16, 32, 128
 427 };
 428
 429 static void __iomem *svia_scr_addr(void __iomem *addr, unsigned int port)
 430 {
 431         return addr + (port * 128);
 432 }
 433
 434 static void __iomem *vt6421_scr_addr(void __iomem *addr, unsigned int port)
 435 {
 436         return addr + (port * 64);
 437 }
 438
 439 static void vt6421_init_addrs(struct ata_port *ap)
 440 {
 441         void __iomem * const * iomap = ap->host->iomap;
 442         void __iomem *reg_addr = iomap[ap->port_no];
 443         void __iomem *bmdma_addr = iomap[4] + (ap->port_no * 8);
 444         struct ata_ioports *ioaddr = &ap->ioaddr;
 445
 446         ioaddr->cmd_addr = reg_addr;
 447         ioaddr->altstatus_addr =
 448         ioaddr->ctl_addr = (void __iomem *)
 449                 ((unsigned long)(reg_addr + 8) | ATA_PCI_CTL_OFS);
 450         ioaddr->bmdma_addr = bmdma_addr;
 451         ioaddr->scr_addr = vt6421_scr_addr(iomap[5], ap->port_no);
 452
 453         ata_sff_std_ports(ioaddr);
 454
 455         ata_port_pbar_desc(ap, ap->port_no, -1, "port");
 456         ata_port_pbar_desc(ap, 4, ap->port_no * 8, "bmdma");
 457 }
 458
 459 static int vt6420_prepare_host(struct pci_dev *pdev, struct ata_host **r_host)
 460 {
 461         const struct ata_port_info *ppi[] = { &vt6420_port_info, NULL };
 462         struct ata_host *host;
 463         int rc;
 464
 465         rc = ata_pci_bmdma_prepare_host(pdev, ppi, &host);
 466         if (rc)
 467                 return rc;
 468         *r_host = host;
 469
 470         rc = pcim_iomap_regions(pdev, 1 << 5, DRV_NAME);
 471         if (rc) {
 472                 dev_err(&pdev->dev, "failed to iomap PCI BAR 5\n");
 473                 return rc;
 474         }
 475
 476         host->ports[0]->ioaddr.scr_addr = svia_scr_addr(host->iomap[5], 0);
 477         host->ports[1]->ioaddr.scr_addr = svia_scr_addr(host->iomap[5], 1);
 478
 479         return 0;
 480 }
 481
 482 static int vt6421_prepare_host(struct pci_dev *pdev, struct ata_host **r_host)
 483 {
 484         const struct ata_port_info *ppi[] =
 485                 { &vt6421_sport_info, &vt6421_sport_info, &vt6421_pport_info };
 486         struct ata_host *host;
 487         int i, rc;
 488
 489         *r_host = host = ata_host_alloc_pinfo(&pdev->dev, ppi, ARRAY_SIZE(ppi));
 490         if (!host) {
 491                 dev_err(&pdev->dev, "failed to allocate host\n");
 492                 return -ENOMEM;
 493         }
 494
 495         rc = pcim_iomap_regions(pdev, 0x3f, DRV_NAME);
 496         if (rc) {
 497                 dev_err(&pdev->dev, "failed to request/iomap PCI BARs (errno=%d)\n",
 498                         rc);
 499                 return rc;
 500         }
 501         host->iomap = pcim_iomap_table(pdev);
 502
 503         for (i = 0; i < host->n_ports; i++)
 504                 vt6421_init_addrs(host->ports[i]);
 505
 506         rc = pci_set_dma_mask(pdev, ATA_DMA_MASK);
 507         if (rc)
 508                 return rc;
 509         rc = pci_set_consistent_dma_mask(pdev, ATA_DMA_MASK);
 510         if (rc)
 511                 return rc;
 512
 513         return 0;
 514 }
 515
 516 static int vt8251_prepare_host(struct pci_dev *pdev, struct ata_host **r_host)
 517 {
 518         const struct ata_port_info *ppi[] = { &vt8251_port_info, NULL };
 519         struct ata_host *host;
 520         int i, rc;
 521
 522         rc = ata_pci_bmdma_prepare_host(pdev, ppi, &host);
 523         if (rc)
 524                 return rc;
 525         *r_host = host;
 526
 527         rc = pcim_iomap_regions(pdev, 1 << 5, DRV_NAME);
 528         if (rc) {
 529                 dev_err(&pdev->dev, "failed to iomap PCI BAR 5\n");
 530                 return rc;
 531         }
 532
 533         /* 8251 hosts four sata ports as M/S of the two channels */
 534         for (i = 0; i < host->n_ports; i++)
 535                 ata_slave_link_init(host->ports[i]);
 536
 537         return 0;
 538 }
 539
 540 static void svia_configure(struct pci_dev *pdev, int board_id)
 541 {
 542         u8 tmp8;
 543
 544         pci_read_config_byte(pdev, PCI_INTERRUPT_LINE, &tmp8);
 545         dev_info(&pdev->dev, "routed to hard irq line %d\n",
 546                  (int) (tmp8 & 0xf0) == 0xf0 ? 0 : tmp8 & 0x0f);
 547
 548         /* make sure SATA channels are enabled */
 549         pci_read_config_byte(pdev, SATA_CHAN_ENAB, &tmp8);
 550         if ((tmp8 & ALL_PORTS) != ALL_PORTS) {
 551                 dev_dbg(&pdev->dev, "enabling SATA channels (0x%x)\n",
 552                         (int)tmp8);
 553                 tmp8 |= ALL_PORTS;
 554                 pci_write_config_byte(pdev, SATA_CHAN_ENAB, tmp8);
 555         }
 556
 557         /* make sure interrupts for each channel sent to us */
 558         pci_read_config_byte(pdev, SATA_INT_GATE, &tmp8);
 559         if ((tmp8 & ALL_PORTS) != ALL_PORTS) {
 560                 dev_dbg(&pdev->dev, "enabling SATA channel interrupts (0x%x)\n",
 561                         (int) tmp8);
 562                 tmp8 |= ALL_PORTS;
 563                 pci_write_config_byte(pdev, SATA_INT_GATE, tmp8);
 564         }
 565
 566         /* make sure native mode is enabled */
 567         pci_read_config_byte(pdev, SATA_NATIVE_MODE, &tmp8);
 568         if ((tmp8 & NATIVE_MODE_ALL) != NATIVE_MODE_ALL) {
 569                 dev_dbg(&pdev->dev,
 570                         "enabling SATA channel native mode (0x%x)\n",
 571                         (int) tmp8);
 572                 tmp8 |= NATIVE_MODE_ALL;
 573                 pci_write_config_byte(pdev, SATA_NATIVE_MODE, tmp8);
 574         }
 575
 576         /*
 577          * vt6420/1 has problems talking to some drives.  The following
 578          * is the fix from Joseph Chan <JosephChan@via.com.tw>.
 579          *
 580          * When host issues HOLD, device may send up to 20DW of data
 581          * before acknowledging it with HOLDA and the host should be
 582          * able to buffer them in FIFO.  Unfortunately, some WD drives
 583          * send up to 40DW before acknowledging HOLD and, in the
 584          * default configuration, this ends up overflowing vt6421's
 585          * FIFO, making the controller abort the transaction with
 586          * R_ERR.
 587          *
 588          * Rx52[2] is the internal 128DW FIFO Flow control watermark
 589          * adjusting mechanism enable bit and the default value 0
 590          * means host will issue HOLD to device when the left FIFO
 591          * size goes below 32DW.  Setting it to 1 makes the watermark
 592          * 64DW.
 593          *
 594          * https://bugzilla.kernel.org/show_bug.cgi?id=15173
 595          * http://article.gmane.org/gmane.linux.ide/46352
 596          * http://thread.gmane.org/gmane.linux.kernel/1062139
 597          */
 598         if (board_id == vt6420 || board_id == vt6421) {
 599                 pci_read_config_byte(pdev, 0x52, &tmp8);
 600                 tmp8 |= 1 << 2;
 601                 pci_write_config_byte(pdev, 0x52, tmp8);
 602         }
 603 }
 604
 605 static int svia_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 606 {
 607         unsigned int i;
 608         int rc;
 609         struct ata_host *host = NULL;
 610         int board_id = (int) ent->driver_data;
 611         const unsigned *bar_sizes;
 612
 613         ata_print_version_once(&pdev->dev, DRV_VERSION);
 614
 615         rc = pcim_enable_device(pdev);
 616         if (rc)
 617                 return rc;
 618
 619         if (board_id == vt6421)
 620                 bar_sizes = &vt6421_bar_sizes[0];
 621         else
 622                 bar_sizes = &svia_bar_sizes[0];
 623
 624         for (i = 0; i < ARRAY_SIZE(svia_bar_sizes); i++)
 625                 if ((pci_resource_start(pdev, i) == 0) ||
 626                     (pci_resource_len(pdev, i) < bar_sizes[i])) {
 627                         dev_err(&pdev->dev,
 628                                 "invalid PCI BAR %u (sz 0x%llx, val 0x%llx)\n",
 629                                 i,
 630                                 (unsigned long long)pci_resource_start(pdev, i),
 631                                 (unsigned long long)pci_resource_len(pdev, i));
 632                         return -ENODEV;
 633                 }
 634
 635         switch (board_id) {
 636         case vt6420:
 637                 rc = vt6420_prepare_host(pdev, &host);
 638                 break;
 639         case vt6421:
 640                 rc = vt6421_prepare_host(pdev, &host);
 641                 break;
 642         case vt8251:
 643                 rc = vt8251_prepare_host(pdev, &host);
 644                 break;
 645         default:
 646                 rc = -EINVAL;
 647         }
 648         if (rc)
 649                 return rc;
 650
 651         svia_configure(pdev, board_id);
 652
 653         pci_set_master(pdev);
 654         return ata_host_activate(host, pdev->irq, ata_bmdma_interrupt,
 655                                  IRQF_SHARED, &svia_sht);
 656 }
 657
 658 module_pci_driver(svia_pci_driver);