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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>
114 lines
2.6 KiB
C
114 lines
2.6 KiB
C
/*
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* pata_netcell.c - Netcell PATA driver
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*
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* (c) 2006 Red Hat <alan@redhat.com>
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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/pci.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 <linux/device.h>
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#include <scsi/scsi_host.h>
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#include <linux/libata.h>
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#include <linux/ata.h>
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#define DRV_NAME "pata_netcell"
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#define DRV_VERSION "0.1.7"
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/* No PIO or DMA methods needed for this device */
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static struct scsi_host_template netcell_sht = {
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ATA_BMDMA_SHT(DRV_NAME),
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};
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static struct ata_port_operations netcell_ops = {
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.inherits = &ata_bmdma_port_ops,
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.cable_detect = ata_cable_80wire,
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};
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/**
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* netcell_init_one - Register Netcell ATA PCI device with kernel services
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* @pdev: PCI device to register
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* @ent: Entry in netcell_pci_tbl matching with @pdev
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*
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* Called from kernel PCI layer.
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*
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* LOCKING:
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* Inherited from PCI layer (may sleep).
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*
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* RETURNS:
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* Zero on success, or -ERRNO value.
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*/
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static int netcell_init_one (struct pci_dev *pdev, const struct pci_device_id *ent)
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{
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static int printed_version;
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static const struct ata_port_info info = {
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.sht = &netcell_sht,
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.flags = ATA_FLAG_SLAVE_POSS,
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/* Actually we don't really care about these as the
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firmware deals with it */
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.pio_mask = 0x1f, /* pio0-4 */
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.mwdma_mask = 0x07, /* mwdma0-2 */
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.udma_mask = ATA_UDMA5, /* UDMA 133 */
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.port_ops = &netcell_ops,
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};
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const struct ata_port_info *port_info[] = { &info, NULL };
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int rc;
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if (!printed_version++)
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dev_printk(KERN_DEBUG, &pdev->dev,
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"version " DRV_VERSION "\n");
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rc = pcim_enable_device(pdev);
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if (rc)
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return rc;
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/* Any chip specific setup/optimisation/messages here */
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ata_pci_clear_simplex(pdev);
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/* And let the library code do the work */
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return ata_pci_init_one(pdev, port_info);
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}
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static const struct pci_device_id netcell_pci_tbl[] = {
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{ PCI_VDEVICE(NETCELL, PCI_DEVICE_ID_REVOLUTION), },
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{ } /* terminate list */
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};
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static struct pci_driver netcell_pci_driver = {
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.name = DRV_NAME,
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.id_table = netcell_pci_tbl,
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.probe = netcell_init_one,
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.remove = ata_pci_remove_one,
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#ifdef CONFIG_PM
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.suspend = ata_pci_device_suspend,
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.resume = ata_pci_device_resume,
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#endif
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};
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static int __init netcell_init(void)
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{
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return pci_register_driver(&netcell_pci_driver);
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}
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static void __exit netcell_exit(void)
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{
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pci_unregister_driver(&netcell_pci_driver);
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}
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module_init(netcell_init);
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module_exit(netcell_exit);
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MODULE_AUTHOR("Alan Cox");
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MODULE_DESCRIPTION("SCSI low-level driver for Netcell PATA RAID");
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MODULE_LICENSE("GPL");
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MODULE_DEVICE_TABLE(pci, netcell_pci_tbl);
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MODULE_VERSION(DRV_VERSION);
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