Re: [git patches] 2.6.x libata updates

[Alan Cox]

On Maw, 2006-01-03 at 12:43 -0500, Jeff Garzik wrote:
> Not really.  If there's no support in mainline, I'm ok with pushing them 
> upstream...  provided that they have been tested and verified to work on 
> at least one machine?  :)

Tested with real hardware and Debian (not enough RAM on MPIIX boxes for
Fedora 8)). The driver mostly duplicates some core code because the
MPIIX isn't quite a PCI IDE controller in the modern sense. That could
be changed to some flags (ALWAYS_LEGACY and DONT_DISABLE) for the core
PCI code but I agree with Bartlomiej sentiment from some time ago that
it is better not to clutter the core libata code with historical
wonders.

Would be slightly cleaner if the core code set adev->pio_mode to PIO0
before doing the identify. Thats something that perhaps should be
handled more specifically by the ATA core since we've no idea how the
BIOS left PATA/SATA controller modes before handing off to us ?


Suggested config entry:

config SCSI_ATA_MPIIX
	tristate "Intel MPIIX PATA support"
	depends on SCSI_SATA && PCI && X86 && !X86_64
	help
	  This option enables support for the Intel MPIIX laptop IDE
	  controller found on some older pentium class laptops.

	  If unsure, say N.


/*
 * pata_mpiix.c 	- Intel MPIIX PATA for new ATA layer
 *			  (C) 2005-2006 Red Hat Inc
 *			  Alan Cox <alan@xxxxxxxxxx>
 *
 * The MPIIX is different enough to the PIIX4 and friends that we give it
 * a separate driver. The old ide/pci code handles this by just not tuning
 * MPIIX at all. 
 *
 * The MPIIX also differs in another important way from the majority of PIIX
 * devices. The chip is a bridge (pardon the pun) between the old world of
 * ISA IDE and PCI IDE. Although the ATA timings are PCI configured the actual
 * IDE controller is not decoded in PCI space and the chip does not claim to
 * be IDE class PCI. This requires slightly non-standard probe logic compared
 * with PCI IDE and also that we do not disable the device when our driver is
 * unloaded (as it has many other functions).
 *
 * The driver conciously keeps this logic internally to avoid pushing quirky
 * PATA history into the clean libata layer.
 *
 * Thinkpad specific note: If you boot an MPIIX using thinkpad with a PCMCIA 
 * hard disk present this driver will not detect it. This is not a bug. In this
 * configuration the secondary port of the MPIIX is disabled and the addresses
 * are decoded by the PCMCIA bridge and therefore are for a generic IDE driver
 * to operate.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/init.h>
#include <linux/blkdev.h>
#include <linux/delay.h>
#include <scsi/scsi_host.h>
#include <linux/libata.h>

#define DRV_NAME "pata_mpiix"
#define DRV_VERSION "0.3"

/**
 *	mpiix_phy_reset		-	probe reset
 *	@ap: ATA port
 *
 *	Perform the ATA probe and bus reset sequence plus specific handling
 *	for this hardware. The MPIIX has the enable bits in a different place
 *	to PIIX4 and friends. As a pure PIO device it has no cable detect
 */

static void mpiix_phy_reset(struct ata_port *ap)
{
	struct pci_dev *pdev = to_pci_dev(ap->host_set->dev);
	static const struct pci_bits mpiix_enable_bits[] = {
		{ 0x6D, 1, 0x80, 0x80 },
		{ 0x6F, 1, 0x80, 0x80 }
	};

	if (!pci_test_config_bits(pdev, &mpiix_enable_bits[ap->hard_port_no])) {
		ata_port_disable(ap);
		printk(KERN_INFO "ata%u: port disabled. ignoring.\n", ap->id);
		return;
	}
	ap->cbl = ATA_CBL_PATA40;
	ata_port_probe(ap);
	ata_bus_reset(ap);
}

/**
 *	mpiix_set_piomode	-	set initial PIO mode data
 *	@ap: ATA interface
 *	@adev: ATA device
 *
 *	Called to do the PIO mode setup. The MPIIX allows us to program the
 *	IORDY sample point (2-5 clocks), recovery 1-4 clocks and whether
 *	prefetching or iordy are used.
 *
 *	This would get very ugly because we can only program timing for one
 *	device at a time, the other gets PIO0. Fortunately libata calls 
 *	our qc_issue_prot command before a command is issued so we can
 *	flip the timings back and forth to reduce the pain.
 */

static void mpiix_set_piomode(struct ata_port *ap, struct ata_device *adev)
{
	int control = 0;
	int pio = adev->pio_mode - XFER_PIO_0;
	struct pci_dev *pdev = to_pci_dev(ap->host_set->dev);
	u16 idetim;
	static const	 /* ISP  RTC */
	u8 timings[][2]	= { { 0, 0 },
			    { 0, 0 },
			    { 1, 0 },
			    { 2, 1 },
			    { 2, 3 }, };

	pci_read_config_word(pdev, 0x6C, &idetim);
	/* Mask the IORDY/TIME/PPE0 bank for this device */
	if (adev->class == ATA_DEV_ATA)
		control |= 4;	/* PPE enable for disk */
	if (ata_pio_need_iordy(adev))
		control |= 2;	/* IORDY */
	if (pio > 0)
		control |= 1;	/* This drive is on the fast timing bank */

	/* Mask out timing and clear both TIME bank selects */
	idetim &= 0xCCEE;
	idetim &= ~(0x07  << (2 * adev->devno));
	idetim |= (control << (2 * adev->devno));
	
	idetim |= (timings[pio][0] << 12) | (timings[pio][1] << 8);
	pci_write_config_word(pdev, 0x6C, idetim);
	
	/* We use ap->private_data as a pointer to the device currently
	   loaded for timing */
	ap->private_data = adev;
}

/**
 *	mpiix_qc_issue_prot	-	command issue
 *	@qc: command pending
 *
 *	Called when the libata layer is about to issue a command. We wrap
 *	this interface so that we can load the correct ATA timings if
 *	neccessary. Our logic also clears TIME0/TIME1 for the other device so
 *	that, even if we get this wrong, cycles to the other device will
 *	be made PIO0.
 */

static int mpiix_qc_issue_prot(struct ata_queued_cmd *qc)
{
	struct ata_port *ap = qc->ap;
	struct ata_device *adev = qc->dev;

	/* If modes have been configured and the channel data is not loaded
	   then load it. We have to check if pio_mode is set as the core code
	   does not set adev->pio_mode to XFER_PIO_0 while probing as would be
	   logical */
	   
	if(adev->pio_mode && adev != ap->private_data)
		mpiix_set_piomode(ap, adev);
		
	return ata_qc_issue_prot(qc);
}

static struct scsi_host_template mpiix_sht = {
	.module			= THIS_MODULE,
	.name			= DRV_NAME,
	.ioctl			= ata_scsi_ioctl,
	.queuecommand		= ata_scsi_queuecmd,
	.eh_strategy_handler	= ata_scsi_error,
	.can_queue		= ATA_DEF_QUEUE,
	.this_id		= ATA_SHT_THIS_ID,
	.sg_tablesize		= LIBATA_MAX_PRD,
	.max_sectors		= ATA_MAX_SECTORS,
	.cmd_per_lun		= ATA_SHT_CMD_PER_LUN,
	.emulated		= ATA_SHT_EMULATED,
	.use_clustering		= ATA_SHT_USE_CLUSTERING,
	.proc_name		= DRV_NAME,
	.dma_boundary		= ATA_DMA_BOUNDARY,
	.slave_configure	= ata_scsi_slave_config,
	.bios_param		= ata_std_bios_param,
	.ordered_flush		= 1,
};

static struct ata_port_operations mpiix_port_ops = {
	.port_disable	= ata_port_disable,
	.set_piomode	= mpiix_set_piomode,

	.tf_load	= ata_tf_load,
	.tf_read	= ata_tf_read,
	.check_status 	= ata_check_status,
	.exec_command	= ata_exec_command,
	.dev_select 	= ata_std_dev_select,

	.phy_reset	= mpiix_phy_reset,

	.qc_prep 	= ata_qc_prep,
	.qc_issue	= mpiix_qc_issue_prot,
	.eng_timeout	= ata_eng_timeout,

	.irq_handler	= ata_interrupt,
	.irq_clear	= ata_bmdma_irq_clear,

	.port_start	= ata_port_start,
	.port_stop	= ata_port_stop,
	.host_stop	= ata_host_stop
};

static int mpiix_init_one(struct pci_dev *dev, const struct pci_device_id *id)
{
	/* Single threaded by the PCI probe logic */
	static struct ata_probe_ent probe[2];
	static int printed_version;
	u16 idetim;
	int ports = 0;
	
	if (!printed_version++)
		dev_printk(KERN_DEBUG, &dev->dev, "version " DRV_VERSION "\n");
		
	/* MPIIX has many functions which can be turned on or off according
	   to other devices present. Make sure IDE is enabled before we try
	   and use it */
	   
	pci_read_config_word(dev, 0x6C, &idetim);
	if(!(idetim & 0x8000))
		return -ENODEV;

	/* We do our own plumbing to avoid leaking special cases for whacko
	   ancient hardware into the core code. There are two issues to 
	   worry about.  #1 The chip is a bridge so if in legacy mode and
	   without BARs set fools the setup.  #2 If you pci_disable_device
	   the MPIIX your box goes castors up */

	INIT_LIST_HEAD(&probe[0].node);
	probe[0].dev = pci_dev_to_dev(dev);
	probe[0].port_ops = &mpiix_port_ops;
	probe[0].sht = &mpiix_sht;
	probe[0].pio_mask = 0x1F;
	probe[0].irq = 14;
	probe[0].irq_flags = SA_SHIRQ;
	probe[0].host_flags = ATA_FLAG_SLAVE_POSS;
	probe[0].legacy_mode = 1;
	probe[0].hard_port_no = 0;
	probe[0].n_ports = 1;
	probe[0].port[0].cmd_addr = 0x1F0;
	probe[0].port[0].ctl_addr = 0x3F6;
	probe[0].port[0].altstatus_addr = 0x3F6;
	
	/* The secondary lurks at different addresses but is otherwise
	   the same beastie */
	   
	INIT_LIST_HEAD(&probe[1].node);
	probe[1] = probe[0];
	probe[1].irq = 15;
	probe[1].hard_port_no = 1;
	probe[1].port[0].cmd_addr = 0x170;
	probe[1].port[0].ctl_addr = 0x376;
	probe[1].port[0].altstatus_addr = 0x376;
	
	/* Let libata fill in the port details */
	ata_std_ports(&probe[0].port[0]);
	ata_std_ports(&probe[1].port[0]);
	
	/* Now add the ports that are active */
	ports += ata_device_add(&probe[0]);
	ports += ata_device_add(&probe[1]);
	if(ports)
		return 0;
	return -ENODEV;
}

/**
 *	mpiix_remove_one	-	device unload
 *	@pdev: PCI device being removed
 *
 *	Handle an unplug/unload event for a PCI device. Unload the
 *	PCI driver but do not use the default handler as we *MUST NOT*
 *	disable the device as it has other functions.
 */
 
static void __devexit mpiix_remove_one(struct pci_dev *pdev)
{
	struct device *dev = pci_dev_to_dev(pdev);
	struct ata_host_set *host_set = dev_get_drvdata(dev);

	ata_host_set_remove(host_set);
	dev_set_drvdata(dev, NULL);
}



static const struct pci_device_id mpiix[] = {
	{ PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82371MX, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0 },
	{ 0, },
};

static struct pci_driver mpiix_pci_driver = {
        .name 		= DRV_NAME,
	.id_table	= mpiix,
	.probe 		= mpiix_init_one,
	.remove		= mpiix_remove_one
};

static int __init mpiix_init(void)
{
	return pci_module_init(&mpiix_pci_driver);
}


static void __exit mpiix_exit(void)
{
	pci_unregister_driver(&mpiix_pci_driver);
}


MODULE_AUTHOR("Alan Cox");
MODULE_DESCRIPTION("low-level driver for Intel MPIIX");
MODULE_LICENSE("GPL");
MODULE_DEVICE_TABLE(pci, mpiix);
MODULE_VERSION(DRV_VERSION);

module_init(mpiix_init);
module_exit(mpiix_exit);