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linux/drivers/ata/pata_radisys.c
Tejun Heo 029cfd6b74 libata: implement and use ops inheritance
libata lets low level drivers build ata_port_operations table and
register it with libata core layer.  This allows low level drivers
high level of flexibility but also burdens them with lots of
boilerplate entries.

This becomes worse for drivers which support related similar
controllers which differ slightly.  They share most of the operations
except for a few.  However, the driver still needs to list all
operations for each variant.  This results in large number of
duplicate entries, which is not only inefficient but also error-prone
as it becomes very difficult to tell what the actual differences are.

This duplicate boilerplates all over the low level drivers also make
updating the core layer exteremely difficult and error-prone.  When
compounded with multi-branched development model, it ends up
accumulating inconsistencies over time.  Some of those inconsistencies
cause immediate problems and fixed.  Others just remain there dormant
making maintenance increasingly difficult.

To rectify the problem, this patch implements ata_port_operations
inheritance.  To allow LLDs to easily re-use their own ops tables
overriding only specific methods, this patch implements poor man's
class inheritance.  An ops table has ->inherits field which can be set
to any ops table as long as it doesn't create a loop.  When the host
is started, the inheritance chain is followed and any operation which
isn't specified is taken from the nearest ancestor which has it
specified.  This operation is called finalization and done only once
per an ops table and the LLD doesn't have to do anything special about
it other than making the ops table non-const such that libata can
update it.

libata provides four base ops tables lower drivers can inherit from -
base, sata, pmp, sff and bmdma.  To avoid overriding these ops
accidentaly, these ops are declared const and LLDs should always
inherit these instead of using them directly.

After finalization, all the ops table are identical before and after
the patch except for setting .irq_handler to ata_interrupt in drivers
which didn't use to.  The .irq_handler doesn't have any actual effect
and the field will soon be removed by later patch.

* sata_sx4 is still using old style EH and currently doesn't take
  advantage of ops inheritance.

Signed-off-by: Tejun Heo <htejun@gmail.com>
2008-04-17 15:44:17 -04:00

271 lines
6.9 KiB
C

/*
* pata_radisys.c - Intel PATA/SATA controllers
*
* (C) 2006 Red Hat <alan@redhat.com>
*
* Some parts based on ata_piix.c by Jeff Garzik and others.
*
* A PIIX relative, this device has a single ATA channel and no
* slave timings, SITRE or PPE. In that sense it is a close relative
* of the original PIIX. It does however support UDMA 33/66 per channel
* although no other modes/timings. Also lacking is 32bit I/O on the ATA
* port.
*/
#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 <linux/device.h>
#include <scsi/scsi_host.h>
#include <linux/libata.h>
#include <linux/ata.h>
#define DRV_NAME "pata_radisys"
#define DRV_VERSION "0.4.4"
/**
* radisys_set_piomode - Initialize host controller PATA PIO timings
* @ap: ATA port
* @adev: Device whose timings we are configuring
*
* Set PIO mode for device, in host controller PCI config space.
*
* LOCKING:
* None (inherited from caller).
*/
static void radisys_set_piomode (struct ata_port *ap, struct ata_device *adev)
{
unsigned int pio = adev->pio_mode - XFER_PIO_0;
struct pci_dev *dev = to_pci_dev(ap->host->dev);
u16 idetm_data;
int control = 0;
/*
* See Intel Document 298600-004 for the timing programing rules
* for PIIX/ICH. Note that the early PIIX does not have the slave
* timing port at 0x44. The Radisys is a relative of the PIIX
* but not the same so be careful.
*/
static const /* ISP RTC */
u8 timings[][2] = { { 0, 0 }, /* Check me */
{ 0, 0 },
{ 1, 1 },
{ 2, 2 },
{ 3, 3 }, };
if (pio > 0)
control |= 1; /* TIME1 enable */
if (ata_pio_need_iordy(adev))
control |= 2; /* IE IORDY */
pci_read_config_word(dev, 0x40, &idetm_data);
/* Enable IE and TIME as appropriate. Clear the other
drive timing bits */
idetm_data &= 0xCCCC;
idetm_data |= (control << (4 * adev->devno));
idetm_data |= (timings[pio][0] << 12) |
(timings[pio][1] << 8);
pci_write_config_word(dev, 0x40, idetm_data);
/* Track which port is configured */
ap->private_data = adev;
}
/**
* radisys_set_dmamode - Initialize host controller PATA DMA timings
* @ap: Port whose timings we are configuring
* @adev: Device to program
* @isich: True if the device is an ICH and has IOCFG registers
*
* Set MWDMA mode for device, in host controller PCI config space.
*
* LOCKING:
* None (inherited from caller).
*/
static void radisys_set_dmamode (struct ata_port *ap, struct ata_device *adev)
{
struct pci_dev *dev = to_pci_dev(ap->host->dev);
u16 idetm_data;
u8 udma_enable;
static const /* ISP RTC */
u8 timings[][2] = { { 0, 0 },
{ 0, 0 },
{ 1, 1 },
{ 2, 2 },
{ 3, 3 }, };
/*
* MWDMA is driven by the PIO timings. We must also enable
* IORDY unconditionally.
*/
pci_read_config_word(dev, 0x40, &idetm_data);
pci_read_config_byte(dev, 0x48, &udma_enable);
if (adev->dma_mode < XFER_UDMA_0) {
unsigned int mwdma = adev->dma_mode - XFER_MW_DMA_0;
const unsigned int needed_pio[3] = {
XFER_PIO_0, XFER_PIO_3, XFER_PIO_4
};
int pio = needed_pio[mwdma] - XFER_PIO_0;
int control = 3; /* IORDY|TIME0 */
/* If the drive MWDMA is faster than it can do PIO then
we must force PIO0 for PIO cycles. */
if (adev->pio_mode < needed_pio[mwdma])
control = 1;
/* Mask out the relevant control and timing bits we will load. Also
clear the other drive TIME register as a precaution */
idetm_data &= 0xCCCC;
idetm_data |= control << (4 * adev->devno);
idetm_data |= (timings[pio][0] << 12) | (timings[pio][1] << 8);
udma_enable &= ~(1 << adev->devno);
} else {
u8 udma_mode;
/* UDMA66 on: UDMA 33 and 66 are switchable via register 0x4A */
pci_read_config_byte(dev, 0x4A, &udma_mode);
if (adev->xfer_mode == XFER_UDMA_2)
udma_mode &= ~ (1 << adev->devno);
else /* UDMA 4 */
udma_mode |= (1 << adev->devno);
pci_write_config_byte(dev, 0x4A, udma_mode);
udma_enable |= (1 << adev->devno);
}
pci_write_config_word(dev, 0x40, idetm_data);
pci_write_config_byte(dev, 0x48, udma_enable);
/* Track which port is configured */
ap->private_data = adev;
}
/**
* radisys_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
* necessary. 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 unsigned int radisys_qc_issue_prot(struct ata_queued_cmd *qc)
{
struct ata_port *ap = qc->ap;
struct ata_device *adev = qc->dev;
if (adev != ap->private_data) {
/* UDMA timing is not shared */
if (adev->dma_mode < XFER_UDMA_0) {
if (adev->dma_mode)
radisys_set_dmamode(ap, adev);
else if (adev->pio_mode)
radisys_set_piomode(ap, adev);
}
}
return ata_qc_issue_prot(qc);
}
static struct scsi_host_template radisys_sht = {
ATA_BMDMA_SHT(DRV_NAME),
};
static struct ata_port_operations radisys_pata_ops = {
.inherits = &ata_bmdma_port_ops,
.qc_issue = radisys_qc_issue_prot,
.cable_detect = ata_cable_unknown,
.set_piomode = radisys_set_piomode,
.set_dmamode = radisys_set_dmamode,
};
/**
* radisys_init_one - Register PIIX ATA PCI device with kernel services
* @pdev: PCI device to register
* @ent: Entry in radisys_pci_tbl matching with @pdev
*
* Called from kernel PCI layer. We probe for combined mode (sigh),
* and then hand over control to libata, for it to do the rest.
*
* LOCKING:
* Inherited from PCI layer (may sleep).
*
* RETURNS:
* Zero on success, or -ERRNO value.
*/
static int radisys_init_one (struct pci_dev *pdev, const struct pci_device_id *ent)
{
static int printed_version;
static const struct ata_port_info info = {
.sht = &radisys_sht,
.flags = ATA_FLAG_SLAVE_POSS,
.pio_mask = 0x1f, /* pio0-4 */
.mwdma_mask = 0x07, /* mwdma1-2 */
.udma_mask = 0x14, /* UDMA33/66 only */
.port_ops = &radisys_pata_ops,
};
const struct ata_port_info *ppi[] = { &info, NULL };
if (!printed_version++)
dev_printk(KERN_DEBUG, &pdev->dev,
"version " DRV_VERSION "\n");
return ata_pci_init_one(pdev, ppi);
}
static const struct pci_device_id radisys_pci_tbl[] = {
{ PCI_VDEVICE(RADISYS, 0x8201), },
{ } /* terminate list */
};
static struct pci_driver radisys_pci_driver = {
.name = DRV_NAME,
.id_table = radisys_pci_tbl,
.probe = radisys_init_one,
.remove = ata_pci_remove_one,
#ifdef CONFIG_PM
.suspend = ata_pci_device_suspend,
.resume = ata_pci_device_resume,
#endif
};
static int __init radisys_init(void)
{
return pci_register_driver(&radisys_pci_driver);
}
static void __exit radisys_exit(void)
{
pci_unregister_driver(&radisys_pci_driver);
}
module_init(radisys_init);
module_exit(radisys_exit);
MODULE_AUTHOR("Alan Cox");
MODULE_DESCRIPTION("SCSI low-level driver for Radisys R82600 controllers");
MODULE_LICENSE("GPL");
MODULE_DEVICE_TABLE(pci, radisys_pci_tbl);
MODULE_VERSION(DRV_VERSION);