it821x.c

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/*
 * linux/drivers/ide/pci/it821x.c		Version 0.16	Jul 3 2007
 *
 * Copyright (C) 2004		Red Hat <[e-mail]>
 * Copyright (C) 2007		Bartlomiej Zolnierkiewicz
 *
 *  May be copied or modified under the terms of the GNU General Public License
 *  Based in part on the ITE vendor provided SCSI driver.
 *
 *  Documentation available from
 * 	http://www.ite.com.tw/pc/IT8212F_V04.pdf
 *  Some other documents are NDA.
 *
 *  The ITE8212 isn't exactly a standard IDE controller. It has two
 *  modes. In pass through mode then it is an IDE controller. In its smart
 *  mode its actually quite a capable hardware raid controller disguised
 *  as an IDE controller. Smart mode only understands DMA read/write and
 *  identify, none of the fancier commands apply. The IT8211 is identical
 *  in other respects but lacks the raid mode.
 *
 *  Errata:
 *  o	Rev 0x10 also requires master/slave hold the same DMA timings and
 *	cannot do ATAPI MWDMA.
 *  o	The identify data for raid volumes lacks CHS info (technically ok)
 *	but also fails to set the LBA28 and other bits. We fix these in
 *	the IDE probe quirk code.
 *  o	If you write LBA48 sized I/O's (ie > 256 sector) in smart mode
 *	raid then the controller firmware dies
 *  o	Smart mode without RAID doesn't clear all the necessary identify
 *	bits to reduce the command set to the one used
 *
 *  This has a few impacts on the driver
 *  - In pass through mode we do all the work you would expect
 *  - In smart mode the clocking set up is done by the controller generally
 *    but we must watch the other limits and filter.
 *  - There are a few extra vendor commands that actually talk to the
 *    controller but only work PIO with no IRQ.
 *
 *  Vendor areas of the identify block in smart mode are used for the
 *  timing and policy set up. Each HDD in raid mode also has a serial
 *  block on the disk. The hardware extra commands are get/set chip status,
 *  rebuild, get rebuild status.
 *
 *  In Linux the driver supports pass through mode as if the device was
 *  just another IDE controller. If the smart mode is running then
 *  volumes are managed by the controller firmware and each IDE "disk"
 *  is a raid volume. Even more cute - the controller can do automated
 *  hotplug and rebuild.
 *
 *  The pass through controller itself is a little demented. It has a
 *  flaw that it has a single set of PIO/MWDMA timings per channel so
 *  non UDMA devices restrict each others performance. It also has a
 *  single clock source per channel so mixed UDMA100/133 performance
 *  isn't perfect and we have to pick a clock. Thankfully none of this
 *  matters in smart mode. ATAPI DMA is not currently supported.
 *
 *  It seems the smart mode is a win for RAID1/RAID10 but otherwise not.
 *
 *  TODO
 *	-	ATAPI UDMA is ok but not MWDMA it seems
 *	-	RAID configuration ioctls
 *	-	Move to libata once it grows up
 */

#include <linux/types.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/delay.h>
#include <linux/hdreg.h>
#include <linux/ide.h>
#include <linux/init.h>

#include <asm/io.h>

struct it821x_dev
{
	unsigned int smart:1,		/* Are we in smart raid mode */
		timing10:1;		/* Rev 0x10 */
	u8	clock_mode;		/* 0, ATA_50 or ATA_66 */
	u8	want[2][2];		/* Mode/Pri log for master slave */
	/* We need these for switching the clock when DMA goes on/off
	   The high byte is the 66Mhz timing */
	u16	pio[2];			/* Cached PIO values */
	u16	mwdma[2];		/* Cached MWDMA values */
	u16	udma[2];		/* Cached UDMA values (per drive) */
};

#define ATA_66		0
#define ATA_50		1
#define ATA_ANY		2

#define UDMA_OFF	0
#define MWDMA_OFF	0

/*
 *	We allow users to force the card into non raid mode without
 *	flashing the alternative BIOS. This is also necessary right now
 *	for embedded platforms that cannot run a PC BIOS but are using this
 *	device.
 */

static int it8212_noraid;

/**
 *	it821x_program	-	program the PIO/MWDMA registers
 *	@drive: drive to tune
 *	@timing: timing info
 *
 *	Program the PIO/MWDMA timing for this channel according to the
 *	current clock.
 */

static void it821x_program(ide_drive_t *drive, u16 timing)
{
	ide_hwif_t *hwif	= drive->hwif;
	struct it821x_dev *itdev = ide_get_hwifdata(hwif);
	int channel = hwif->channel;
	u8 conf;

	/* Program PIO/MWDMA timing bits */
	if(itdev->clock_mode == ATA_66)
		conf = timing >> 8;
	else
		conf = timing & 0xFF;
	pci_write_config_byte(hwif->pci_dev, 0x54 + 4 * channel, conf);
}

/**
 *	it821x_program_udma	-	program the UDMA registers
 *	@drive: drive to tune
 *	@timing: timing info
 *
 *	Program the UDMA timing for this drive according to the
 *	current clock.
 */

static void it821x_program_udma(ide_drive_t *drive, u16 timing)
{
	ide_hwif_t *hwif	= drive->hwif;
	struct it821x_dev *itdev = ide_get_hwifdata(hwif);
	int channel = hwif->channel;
	int unit = drive->select.b.unit;
	u8 conf;

	/* Program UDMA timing bits */
	if(itdev->clock_mode == ATA_66)
		conf = timing >> 8;
	else
		conf = timing & 0xFF;
	if(itdev->timing10 == 0)
		pci_write_config_byte(hwif->pci_dev, 0x56 + 4 * channel + unit, conf);
	else {
		pci_write_config_byte(hwif->pci_dev, 0x56 + 4 * channel, conf);
		pci_write_config_byte(hwif->pci_dev, 0x56 + 4 * channel + 1, conf);
	}
}

/**
 *	it821x_clock_strategy
 *	@drive: drive to set up
 *
 *	Select between the 50 and 66Mhz base clocks to get the best
 *	results for this interface.
 */

static void it821x_clock_strategy(ide_drive_t *drive)
{
	ide_hwif_t *hwif = drive->hwif;
	struct it821x_dev *itdev = ide_get_hwifdata(hwif);

	u8 unit = drive->select.b.unit;
	ide_drive_t *pair = &hwif->drives[1-unit];

	int clock, altclock;
	u8 v;
	int sel = 0;

	if(itdev->want[0][0] > itdev->want[1][0]) {
		clock = itdev->want[0][1];
		altclock = itdev->want[1][1];
	} else {
		clock = itdev->want[1][1];
		altclock = itdev->want[0][1];
	}

	/*
	 * if both clocks can be used for the mode with the higher priority
	 * use the clock needed by the mode with the lower priority
	 */
	if (clock == ATA_ANY)
		clock = altclock;

	/* Nobody cares - keep the same clock */
	if(clock == ATA_ANY)
		return;
	/* No change */
	if(clock == itdev->clock_mode)
		return;

	/* Load this into the controller ? */
	if(clock == ATA_66)
		itdev->clock_mode = ATA_66;
	else {
		itdev->clock_mode = ATA_50;
		sel = 1;
	}
	pci_read_config_byte(hwif->pci_dev, 0x50, &v);
	v &= ~(1 << (1 + hwif->channel));
	v |= sel << (1 + hwif->channel);
	pci_write_config_byte(hwif->pci_dev, 0x50, v);

	/*
	 *	Reprogram the UDMA/PIO of the pair drive for the switch
	 *	MWDMA will be dealt with by the dma switcher
	 */
	if(pair && itdev->udma[1-unit] != UDMA_OFF) {
		it821x_program_udma(pair, itdev->udma[1-unit]);
		it821x_program(pair, itdev->pio[1-unit]);
	}
	/*
	 *	Reprogram the UDMA/PIO of our drive for the switch.
	 *	MWDMA will be dealt with by the dma switcher
	 */
	if(itdev->udma[unit] != UDMA_OFF) {
		it821x_program_udma(drive, itdev->udma[unit]);
		it821x_program(drive, itdev->pio[unit]);
	}
}

/**
 *	it821x_set_pio_mode	-	set host controller for PIO mode
 *	@drive: drive
 *	@pio: PIO mode number
 *
 *	Tune the host to the desired PIO mode taking into the consideration
 *	the maximum PIO mode supported by the other device on the cable.
 */

static void it821x_set_pio_mode(ide_drive_t *drive, const u8 pio)
{
	ide_hwif_t *hwif	= drive->hwif;
	struct it821x_dev *itdev = ide_get_hwifdata(hwif);
	int unit = drive->select.b.unit;
	ide_drive_t *pair = &hwif->drives[1 - unit];
	u8 set_pio = pio;

	/* Spec says 89 ref driver uses 88 */
	static u16 pio_timings[]= { 0xAA88, 0xA382, 0xA181, 0x3332, 0x3121 };
	static u8 pio_want[]    = { ATA_66, ATA_66, ATA_66, ATA_66, ATA_ANY };

	/*
	 * Compute the best PIO mode we can for a given device. We must
	 * pick a speed that does not cause problems with the other device
	 * on the cable.
	 */
	if (pair) {
		u8 pair_pio = ide_get_best_pio_mode(pair, 255, 4);
		/* trim PIO to the slowest of the master/slave */
		if (pair_pio < set_pio)
			set_pio = pair_pio;
	}

	/* We prefer 66Mhz clock for PIO 0-3, don't care for PIO4 */
	itdev->want[unit][1] = pio_want[set_pio];
	itdev->want[unit][0] = 1;	/* PIO is lowest priority */
	itdev->pio[unit] = pio_timings[set_pio];
	it821x_clock_strategy(drive);
	it821x_program(drive, itdev->pio[unit]);
}

/**
 *	it821x_tune_mwdma	-	tune a channel for MWDMA
 *	@drive: drive to set up
 *	@mode_wanted: the target operating mode
 *
 *	Load the timing settings for this device mode into the
 *	controller when doing MWDMA in pass through mode. The caller
 *	must manage the whole lack of per device MWDMA/PIO timings and
 *	the shared MWDMA/PIO timing register.
 */

static void it821x_tune_mwdma (ide_drive_t *drive, byte mode_wanted)
{
	ide_hwif_t *hwif	= drive->hwif;
	struct it821x_dev *itdev = (void *)ide_get_hwifdata(hwif);
	int unit = drive->select.b.unit;
	int channel = hwif->channel;
	u8 conf;

	static u16 dma[]	= { 0x8866, 0x3222, 0x3121 };
	static u8 mwdma_want[]	= { ATA_ANY, ATA_66, ATA_ANY };

	itdev->want[unit][1] = mwdma_want[mode_wanted];
	itdev->want[unit][0] = 2;	/* MWDMA is low priority */
	itdev->mwdma[unit] = dma[mode_wanted];
	itdev->udma[unit] = UDMA_OFF;

	/* UDMA bits off - Revision 0x10 do them in pairs */
	pci_read_config_byte(hwif->pci_dev, 0x50, &conf);
	if(itdev->timing10)
		conf |= channel ? 0x60: 0x18;
	else
		conf |= 1 << (3 + 2 * channel + unit);
	pci_write_config_byte(hwif->pci_dev, 0x50, conf);

	it821x_clock_strategy(drive);
	/* FIXME: do we need to program this ? */
	/* it821x_program(drive, itdev->mwdma[unit]); */
}

/**
 *	it821x_tune_udma	-	tune a channel for UDMA
 *	@drive: drive to set up
 *	@mode_wanted: the target operating mode
 *
 *	Load the timing settings for this device mode into the
 *	controller when doing UDMA modes in pass through.
 */

static void it821x_tune_udma (ide_drive_t *drive, byte mode_wanted)
{
	ide_hwif_t *hwif	= drive->hwif;
	struct it821x_dev *itdev = ide_get_hwifdata(hwif);
	int unit = drive->select.b.unit;
	int channel = hwif->channel;
	u8 conf;

	static u16 udma[]	= { 0x4433, 0x4231, 0x3121, 0x2121, 0x1111, 0x2211, 0x1111 };
	static u8 udma_want[]	= { ATA_ANY, ATA_50, ATA_ANY, ATA_66, ATA_66, ATA_50, ATA_66 };

	itdev->want[unit][1] = udma_want[mode_wanted];
	itdev->want[unit][0] = 3;	/* UDMA is high priority */
	itdev->mwdma[unit] = MWDMA_OFF;
	itdev->udma[unit] = udma[mode_wanted];
	if(mode_wanted >= 5)
		itdev->udma[unit] |= 0x8080;	/* UDMA 5/6 select on */

	/* UDMA on. Again revision 0x10 must do the pair */
	pci_read_config_byte(hwif->pci_dev, 0x50, &conf);
	if(itdev->timing10)
		conf &= channel ? 0x9F: 0xE7;
	else