linux/drivers/ata/pata_ns87410.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

205 lines
5.4 KiB
C

/*
* pata_ns87410.c - National Semiconductor 87410 PATA for new ATA layer
* (C) 2006 Red Hat Inc
* Alan Cox <alan@redhat.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; see the file COPYING. If not, write to
* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#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_ns87410"
#define DRV_VERSION "0.4.6"
/**
* ns87410_pre_reset - probe begin
* @link: ATA link
* @deadline: deadline jiffies for the operation
*
* Check enabled ports
*/
static int ns87410_pre_reset(struct ata_link *link, unsigned long deadline)
{
struct ata_port *ap = link->ap;
struct pci_dev *pdev = to_pci_dev(ap->host->dev);
static const struct pci_bits ns87410_enable_bits[] = {
{ 0x43, 1, 0x08, 0x08 },
{ 0x47, 1, 0x08, 0x08 }
};
if (!pci_test_config_bits(pdev, &ns87410_enable_bits[ap->port_no]))
return -ENOENT;
return ata_std_prereset(link, deadline);
}
/**
* ns87410_error_handler - 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 ns87410_error_handler(struct ata_port *ap)
{
ata_bmdma_drive_eh(ap, ns87410_pre_reset, ata_std_softreset, NULL, ata_std_postreset);
}
/**
* ns87410_set_piomode - set initial PIO mode data
* @ap: ATA interface
* @adev: ATA device
*
* Program timing data. This is kept per channel not per device,
* and only affects the data port.
*/
static void ns87410_set_piomode(struct ata_port *ap, struct ata_device *adev)
{
struct pci_dev *pdev = to_pci_dev(ap->host->dev);
int port = 0x40 + 4 * ap->port_no;
u8 idetcr, idefr;
struct ata_timing at;
static const u8 activebits[15] = {
0, 1, 2, 3, 4,
5, 5, 6, 6, 6,
6, 7, 7, 7, 7
};
static const u8 recoverbits[12] = {
0, 1, 2, 3, 4, 5, 6, 6, 7, 7, 7, 7
};
pci_read_config_byte(pdev, port + 3, &idefr);
if (ata_pio_need_iordy(adev))
idefr |= 0x04; /* IORDY enable */
else
idefr &= ~0x04;
if (ata_timing_compute(adev, adev->pio_mode, &at, 30303, 1) < 0) {
dev_printk(KERN_ERR, &pdev->dev, "unknown mode %d.\n", adev->pio_mode);
return;
}
at.active = FIT(at.active, 2, 16) - 2;
at.setup = FIT(at.setup, 1, 4) - 1;
at.recover = FIT(at.recover, 1, 12) - 1;
idetcr = (at.setup << 6) | (recoverbits[at.recover] << 3) | activebits[at.active];
pci_write_config_byte(pdev, port, idetcr);
pci_write_config_byte(pdev, port + 3, idefr);
/* We use ap->private_data as a pointer to the device currently
loaded for timing */
ap->private_data = adev;
}
/**
* ns87410_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.
*/
static unsigned int ns87410_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)
ns87410_set_piomode(ap, adev);
return ata_qc_issue_prot(qc);
}
static struct scsi_host_template ns87410_sht = {
ATA_PIO_SHT(DRV_NAME),
};
static struct ata_port_operations ns87410_port_ops = {
.inherits = &ata_sff_port_ops,
.qc_issue = ns87410_qc_issue_prot,
.cable_detect = ata_cable_40wire,
.set_piomode = ns87410_set_piomode,
.error_handler = ns87410_error_handler,
};
static int ns87410_init_one(struct pci_dev *dev, const struct pci_device_id *id)
{
static const struct ata_port_info info = {
.sht = &ns87410_sht,
.flags = ATA_FLAG_SLAVE_POSS,
.pio_mask = 0x0F,
.port_ops = &ns87410_port_ops
};
const struct ata_port_info *ppi[] = { &info, NULL };
return ata_pci_init_one(dev, ppi);
}
static const struct pci_device_id ns87410[] = {
{ PCI_VDEVICE(NS, PCI_DEVICE_ID_NS_87410), },
{ },
};
static struct pci_driver ns87410_pci_driver = {
.name = DRV_NAME,
.id_table = ns87410,
.probe = ns87410_init_one,
.remove = ata_pci_remove_one,
#ifdef CONFIG_PM
.suspend = ata_pci_device_suspend,
.resume = ata_pci_device_resume,
#endif
};
static int __init ns87410_init(void)
{
return pci_register_driver(&ns87410_pci_driver);
}
static void __exit ns87410_exit(void)
{
pci_unregister_driver(&ns87410_pci_driver);
}
MODULE_AUTHOR("Alan Cox");
MODULE_DESCRIPTION("low-level driver for Nat Semi 87410");
MODULE_LICENSE("GPL");
MODULE_DEVICE_TABLE(pci, ns87410);
MODULE_VERSION(DRV_VERSION);
module_init(ns87410_init);
module_exit(ns87410_exit);