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029cfd6b74
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>
140 lines
3.1 KiB
C
140 lines
3.1 KiB
C
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/*
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* pata-isapnp.c - ISA PnP PATA controller driver.
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* Copyright 2005/2006 Red Hat Inc <alan@redhat.com>, all rights reserved.
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*
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* Based in part on ide-pnp.c by Andrey Panin <pazke@donpac.ru>
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/isapnp.h>
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#include <linux/init.h>
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#include <linux/blkdev.h>
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#include <linux/delay.h>
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#include <scsi/scsi_host.h>
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#include <linux/ata.h>
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#include <linux/libata.h>
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#define DRV_NAME "pata_isapnp"
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#define DRV_VERSION "0.2.2"
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static struct scsi_host_template isapnp_sht = {
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ATA_PIO_SHT(DRV_NAME),
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};
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static struct ata_port_operations isapnp_port_ops = {
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.inherits = &ata_sff_port_ops,
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.cable_detect = ata_cable_40wire,
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};
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/**
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* isapnp_init_one - attach an isapnp interface
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* @idev: PnP device
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* @dev_id: matching detect line
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*
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* Register an ISA bus IDE interface. Such interfaces are PIO 0 and
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* non shared IRQ.
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*/
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static int isapnp_init_one(struct pnp_dev *idev, const struct pnp_device_id *dev_id)
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{
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struct ata_host *host;
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struct ata_port *ap;
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void __iomem *cmd_addr, *ctl_addr;
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int irq = 0;
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irq_handler_t handler = NULL;
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if (pnp_port_valid(idev, 0) == 0)
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return -ENODEV;
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if (pnp_irq_valid(idev, 0)) {
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irq = pnp_irq(idev, 0);
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handler = ata_interrupt;
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}
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/* allocate host */
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host = ata_host_alloc(&idev->dev, 1);
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if (!host)
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return -ENOMEM;
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/* acquire resources and fill host */
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cmd_addr = devm_ioport_map(&idev->dev, pnp_port_start(idev, 0), 8);
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if (!cmd_addr)
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return -ENOMEM;
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ap = host->ports[0];
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ap->ops = &isapnp_port_ops;
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ap->pio_mask = 1;
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ap->flags |= ATA_FLAG_SLAVE_POSS;
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ap->ioaddr.cmd_addr = cmd_addr;
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if (pnp_port_valid(idev, 1) == 0) {
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ctl_addr = devm_ioport_map(&idev->dev,
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pnp_port_start(idev, 1), 1);
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ap->ioaddr.altstatus_addr = ctl_addr;
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ap->ioaddr.ctl_addr = ctl_addr;
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}
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ata_std_ports(&ap->ioaddr);
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ata_port_desc(ap, "cmd 0x%llx ctl 0x%llx",
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(unsigned long long)pnp_port_start(idev, 0),
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(unsigned long long)pnp_port_start(idev, 1));
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/* activate */
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return ata_host_activate(host, irq, handler, 0,
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&isapnp_sht);
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}
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/**
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* isapnp_remove_one - unplug an isapnp interface
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* @idev: PnP device
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*
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* Remove a previously configured PnP ATA port. Called only on module
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* unload events as the core does not currently deal with ISAPnP docking.
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*/
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static void isapnp_remove_one(struct pnp_dev *idev)
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{
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struct device *dev = &idev->dev;
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struct ata_host *host = dev_get_drvdata(dev);
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ata_host_detach(host);
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}
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static struct pnp_device_id isapnp_devices[] = {
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/* Generic ESDI/IDE/ATA compatible hard disk controller */
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{.id = "PNP0600", .driver_data = 0},
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{.id = ""}
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};
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MODULE_DEVICE_TABLE(pnp, isapnp_devices);
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static struct pnp_driver isapnp_driver = {
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.name = DRV_NAME,
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.id_table = isapnp_devices,
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.probe = isapnp_init_one,
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.remove = isapnp_remove_one,
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};
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static int __init isapnp_init(void)
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{
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return pnp_register_driver(&isapnp_driver);
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}
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static void __exit isapnp_exit(void)
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{
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pnp_unregister_driver(&isapnp_driver);
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}
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MODULE_AUTHOR("Alan Cox");
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MODULE_DESCRIPTION("low-level driver for ISA PnP ATA");
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MODULE_LICENSE("GPL");
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MODULE_VERSION(DRV_VERSION);
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module_init(isapnp_init);
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module_exit(isapnp_exit);
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