via82cxxx.c

讲述linux的初始化过程

	if (active + recover < cycle) {
		active += (cycle - (active + recover)) / 2;
		recover = cycle - active;
	}

/*
 * PIO address setup
 */

	pci_read_config_byte(dev, VIA_ADDRESS_SETUP, &t);
	t = (t & ~(3 << ((3 - drive->dn) << 1))) | (FIT(setup - 1, 0, 3) << ((3 - drive->dn) << 1));
	via_write_config_byte(dev, VIA_ADDRESS_SETUP, t);

/*
 * PIO active & recover
 */

	via_write_config_byte(dev, VIA_DRIVE_TIMING + (3 - drive->dn),
		(FIT(active - 1, 0, 0xf) << 4) | FIT(recover - 1, 0, 0xf));

/*
 * UDMA cycle
 */

	switch(via_isa_bridges[via_config].speed) {
		case XFER_UDMA_2: t = via_timing[i].udma ? (0xe0 | (FIT(ENOUGH(via_timing[i].udma, T), 2, 5) - 2)) : 0x03; break;
		case XFER_UDMA_4: t = via_timing[i].udma ? (0xe8 | (FIT(ENOUGH(via_timing[i].udma, T/2), 2, 9) - 2)) : 0x0f; break;
        }

	if (via_isa_bridges[via_config].speed != XFER_MW_DMA_2)
		via_write_config_byte(dev, VIA_UDMA_TIMING + (3 - drive->dn), t);

/*
 * Drive init
 */

	if (!drive->init_speed) drive->init_speed = speed;
	if ((err = ide_config_drive_speed(drive, speed)))
		return err;
	drive->current_speed = speed;

	return 0;
}

static void config_chipset_for_pio(ide_drive_t *drive)
{
	short eide_pio_timing[] = {600, 383, 240, 180, 120, 100};
	signed char pio, ide_pio;

	if (drive->id->eide_pio_iordy > 0) {	/* Has timing table */
		for (pio = 5; pio >= 0; pio--)
			if (drive->id->eide_pio_iordy <= eide_pio_timing[pio])
				break;
	} else {				/* No timing table -> use mode capabilities */
		pio = (drive->id->eide_pio_modes & 4) ? 5 :
		      (drive->id->eide_pio_modes & 2) ? 4 :
		      (drive->id->eide_pio_modes & 1) ? 3 :
		      (drive->id->tPIO == 2) ? 2 :
		      (drive->id->tPIO == 1) ? 1 : 0;
	}

	ide_pio = ide_get_best_pio_mode(drive, 255, 5, NULL);
	pio = (pio >= ide_pio) ? pio : ide_pio;	/* Phew. What about the blacklist? */

	if (!pio) pio = (!drive->id->tPIO) ? XFER_PIO_0 : XFER_PIO_SLOW;
		else pio += XFER_PIO_0;

	/* Fixup because of broken ide-probe.c */
	drive->dn = HWIF(drive)->channel * 2 + (drive->select.b.unit & 1); 

	via_set_speed(drive, pio);
}

static void via82cxxx_tune_drive(ide_drive_t *drive, byte pio)
{
	if (pio == 255) {
		config_chipset_for_pio(drive);
		return;
	}
	
	if (pio > 5) pio = 5;
	
	via_set_speed(drive, XFER_PIO_0 + pio);
}

#ifdef CONFIG_BLK_DEV_IDEDMA

static int config_chipset_for_dma(ide_drive_t *drive)
{
	struct hd_driveid *id = drive->id;
	unsigned char ultra66 = eighty_ninty_three(drive);
	unsigned char speed =

		((id->dma_ultra & 0x0010) && ultra66) ? XFER_UDMA_4 :
		((id->dma_ultra & 0x0008) && ultra66) ? XFER_UDMA_3 :
		(id->dma_ultra & 0x0004) ? XFER_UDMA_2 :
		(id->dma_ultra & 0x0002) ? XFER_UDMA_1 :
		(id->dma_ultra & 0x0001) ? XFER_UDMA_0 :
		(id->dma_mword & 0x0004) ? XFER_MW_DMA_2 :
		(id->dma_mword & 0x0002) ? XFER_MW_DMA_1 :
		(id->dma_mword & 0x0001) ? XFER_MW_DMA_0 :
		(id->dma_1word & 0x0004) ? XFER_SW_DMA_2 :
		(id->dma_1word & 0x0002) ? XFER_SW_DMA_1 :
		(id->dma_1word & 0x0001) ? XFER_SW_DMA_0 : 0;
		
	if (!speed) return (int) ide_dma_off_quietly;

	via_set_speed(drive, speed);

	return (int) ide_dma_on;
}

/*
 * Almost a library function.
 */

static int config_drive_xfer_rate(ide_drive_t *drive)
{
	struct hd_driveid *id = drive->id;
	ide_dma_action_t dma_func = ide_dma_on;

	if (id && (id->capability & 1) && HWIF(drive)->autodma) {
		/* Consult the list of known "bad" drives */
		if (ide_dmaproc(ide_dma_bad_drive, drive)) {
			dma_func = ide_dma_off;
			goto fast_ata_pio;
		}
		dma_func = ide_dma_off_quietly;
		if (id->field_valid & 4) {
			if (id->dma_ultra & 0x002F) {
				/* Force if Capable UltraDMA */
				dma_func = config_chipset_for_dma(drive);
				if ((id->field_valid & 2) &&
				    (dma_func != ide_dma_on))
					goto try_dma_modes;
			}
		} else if (id->field_valid & 2) {
try_dma_modes:
			if (id->dma_mword & 0x0007) {
				/* Force if Capable regular DMA modes */
				dma_func = config_chipset_for_dma(drive);
				if (dma_func != ide_dma_on)
					goto no_dma_set;
			}
		} else if (ide_dmaproc(ide_dma_good_drive, drive)) {
			if (id->eide_dma_time > 150) {
				goto no_dma_set;
			}
			/* Consult the list of known "good" drives */
			dma_func = config_chipset_for_dma(drive);
			if (dma_func != ide_dma_on)
				goto no_dma_set;
		} else {
			goto fast_ata_pio;
		}
	} else if ((id->capability & 8) || (id->field_valid & 2)) {
fast_ata_pio:
		dma_func = ide_dma_off_quietly;
no_dma_set:
		config_chipset_for_pio(drive);
	}
	return HWIF(drive)->dmaproc(dma_func, drive);
}


int via82cxxx_dmaproc(ide_dma_action_t func, ide_drive_t *drive)
{
	if (func == ide_dma_check)
			return config_drive_xfer_rate(drive);
	return ide_dmaproc(func, drive);
}
#endif /* CONFIG_BLK_DEV_IDEDMA */

unsigned int __init pci_init_via82cxxx(struct pci_dev *dev, const char *name)
{
	struct pci_dev *isa = NULL;
	unsigned char f, t, m;
	unsigned int u, i;

/*
 * Find ISA bridge to see how good the IDE is.
 */

	for (via_config = 0; via_isa_bridges[via_config].id; via_config++)
		if ((isa = pci_find_device(PCI_VENDOR_ID_VIA, via_isa_bridges[via_config].id, NULL)))	
			break;
/*
 * Read revision.
 */

	if (via_isa_bridges[via_config].id == PCI_DEVICE_ID_VIA_82C586_0) {
		pci_read_config_byte(isa, PCI_REVISION_ID, &t);
		if (t < 0x30) via_config++;			/* vt82c586a */
		if (t < 0x20) via_config++;			/* vt82c586 */
	}

	if (via_isa_bridges[via_config].id == PCI_DEVICE_ID_VIA_82C596) {
		pci_read_config_byte(isa, PCI_REVISION_ID, &t);
		if (t < 0x10) via_config++;			/* vt82c596a */
	}

/*
 * Check UDMA66 mode set by BIOS.
 */

	pci_read_config_dword(dev, VIA_UDMA_TIMING, &u);

	for (i = 0; i < 4; i++) {
		pci_read_config_byte(dev, VIA_UDMA_TIMING + (3 - i), &t);
		if ((u & (0x80000 >> ((i >> 1) << 4))) && ((t & 7) < 2)) via_ata66 |= (1 << (i >> 1));
	} 

#ifdef DEBUG
	printk(KERN_DEBUG "VP_IDE: BIOS enabled ATA66: primary: %s, secondary: %s\n",
		via_ata66 & 1 ? "yes" : "no", via_ata66 & 2 ? "yes" : "no");
#endif

/*
 * Set UDMA66 double clock bits.
 */
	if (via_isa_bridges[via_config].speed == XFER_UDMA_4)
		pci_write_config_dword(dev, VIA_UDMA_TIMING, u | 0x80008);

/*
 * Set up FIFO, flush, prefetch and post-writes.
 */

	pci_read_config_dword(dev, VIA_IDE_ENABLE, &u);
	pci_read_config_byte(dev, VIA_FIFO_CONFIG, &f);
	pci_read_config_byte(dev, VIA_IDE_CONFIG, &t);
	pci_read_config_byte(dev, VIA_MISC_3, &m);

	f &= 0x90; t &= 0x0f; m &= 0x0f;

	switch (u & 3) {
		case 2: via_enabled = 1; f |= 0x06; t |= 0xc0; m |= 0xa0; break;	/* primary only, 3/4 */
		case 1: via_enabled = 2; f |= 0x69; t |= 0x30; m |= 0x50; break;	/* secondary only, 3/4 */
		case 3: via_enabled = 3;
		default:                 f |= 0x2a; t |= 0xf0; m |= 0xf0; break;	/* fifo evenly distributed */
	}

	via_write_config_byte(dev, VIA_FIFO_CONFIG, f);
	via_write_config_byte(dev, VIA_IDE_CONFIG, t);
	via_write_config_byte(dev, VIA_MISC_3, m);

/*
 * Print the boot message.
 */

	printk(KERN_INFO "VP_IDE: VIA %s IDE %s controller on pci%d:%d.%d\n",
			via_isa_bridges[via_config].name,
			via_isa_bridges[via_config].speed >= XFER_UDMA_4 ? "UDMA66" :
			via_isa_bridges[via_config].speed >= XFER_UDMA_2 ? "UDMA33" : "MWDMA16",
			dev->bus->number, PCI_SLOT(dev->devfn), PCI_FUNC(dev->devfn));
/*
 * Register /proc/ide/via entry
 */

#if defined(CONFIG_PROC_FS)
	if (!via_proc) {
		via_proc = 1;
		bmide_dev = dev;
		isa_dev = isa;
		via_display_info = &via_get_info;
	}
#endif

	return 0;
}

/*
 * Since we don't have a way to detect the 80-wire ribbon cable
 * we rely on the BIOS detection. We also check the IDENTIFY byte
 * 93 to check the drive's point of view. I think we could return
 * '1' here 
 */

unsigned int __init ata66_via82cxxx(ide_hwif_t *hwif)
{
	return ((via_enabled & via_ata66) >> hwif->channel) & 1;
}

void __init ide_init_via82cxxx(ide_hwif_t *hwif)
{
	hwif->tuneproc = &via82cxxx_tune_drive;
	hwif->speedproc = &via_set_speed;
	hwif->drives[0].autotune = 1;
	hwif->drives[1].autotune = 1;
	hwif->autodma = 0;

#ifdef CONFIG_BLK_DEV_IDEDMA
	if (hwif->dma_base) {
		hwif->dmaproc = &via82cxxx_dmaproc;
		hwif->autodma = 1;
	}
#endif /* CONFIG_BLK_DEV_IDEDMA */
}

/*
 * We allow the BM-DMA driver only work on enabled interfaces.
 */

void __init ide_dmacapable_via82cxxx(ide_hwif_t *hwif, unsigned long dmabase)
{
	if ((via_enabled >> hwif->channel) & 1)
		ide_setup_dma(hwif, dmabase, 8);
}