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![Tejun Heo](/assets/img/avatar_default.png)
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>
279 lines
7.4 KiB
C
279 lines
7.4 KiB
C
/*
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* Generic platform device PATA driver
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*
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* Copyright (C) 2006 - 2007 Paul Mundt
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*
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* Based on pata_pcmcia:
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*
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* Copyright 2005-2006 Red Hat Inc <alan@redhat.com>, all rights reserved.
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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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/init.h>
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#include <linux/blkdev.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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#include <linux/platform_device.h>
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#include <linux/ata_platform.h>
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#define DRV_NAME "pata_platform"
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#define DRV_VERSION "1.2"
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static int pio_mask = 1;
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/*
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* Provide our own set_mode() as we don't want to change anything that has
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* already been configured..
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*/
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static int pata_platform_set_mode(struct ata_link *link, struct ata_device **unused)
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{
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struct ata_device *dev;
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ata_link_for_each_dev(dev, link) {
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if (ata_dev_enabled(dev)) {
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/* We don't really care */
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dev->pio_mode = dev->xfer_mode = XFER_PIO_0;
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dev->xfer_shift = ATA_SHIFT_PIO;
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dev->flags |= ATA_DFLAG_PIO;
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ata_dev_printk(dev, KERN_INFO, "configured for PIO\n");
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}
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}
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return 0;
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}
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static struct scsi_host_template pata_platform_sht = {
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ATA_PIO_SHT(DRV_NAME),
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};
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static struct ata_port_operations pata_platform_port_ops = {
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.inherits = &ata_sff_port_ops,
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.data_xfer = ata_data_xfer_noirq,
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.cable_detect = ata_cable_unknown,
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.set_mode = pata_platform_set_mode,
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.port_start = ATA_OP_NULL,
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};
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static void pata_platform_setup_port(struct ata_ioports *ioaddr,
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unsigned int shift)
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{
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/* Fixup the port shift for platforms that need it */
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ioaddr->data_addr = ioaddr->cmd_addr + (ATA_REG_DATA << shift);
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ioaddr->error_addr = ioaddr->cmd_addr + (ATA_REG_ERR << shift);
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ioaddr->feature_addr = ioaddr->cmd_addr + (ATA_REG_FEATURE << shift);
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ioaddr->nsect_addr = ioaddr->cmd_addr + (ATA_REG_NSECT << shift);
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ioaddr->lbal_addr = ioaddr->cmd_addr + (ATA_REG_LBAL << shift);
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ioaddr->lbam_addr = ioaddr->cmd_addr + (ATA_REG_LBAM << shift);
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ioaddr->lbah_addr = ioaddr->cmd_addr + (ATA_REG_LBAH << shift);
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ioaddr->device_addr = ioaddr->cmd_addr + (ATA_REG_DEVICE << shift);
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ioaddr->status_addr = ioaddr->cmd_addr + (ATA_REG_STATUS << shift);
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ioaddr->command_addr = ioaddr->cmd_addr + (ATA_REG_CMD << shift);
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}
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/**
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* __pata_platform_probe - attach a platform interface
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* @dev: device
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* @io_res: Resource representing I/O base
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* @ctl_res: Resource representing CTL base
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* @irq_res: Resource representing IRQ and its flags
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* @ioport_shift: I/O port shift
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* @__pio_mask: PIO mask
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*
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* Register a platform bus IDE interface. Such interfaces are PIO and we
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* assume do not support IRQ sharing.
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*
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* Platform devices are expected to contain at least 2 resources per port:
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*
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* - I/O Base (IORESOURCE_IO or IORESOURCE_MEM)
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* - CTL Base (IORESOURCE_IO or IORESOURCE_MEM)
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*
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* and optionally:
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*
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* - IRQ (IORESOURCE_IRQ)
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*
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* If the base resources are both mem types, the ioremap() is handled
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* here. For IORESOURCE_IO, it's assumed that there's no remapping
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* necessary.
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*
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* If no IRQ resource is present, PIO polling mode is used instead.
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*/
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int __devinit __pata_platform_probe(struct device *dev,
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struct resource *io_res,
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struct resource *ctl_res,
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struct resource *irq_res,
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unsigned int ioport_shift,
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int __pio_mask)
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{
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struct ata_host *host;
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struct ata_port *ap;
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unsigned int mmio;
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int irq = 0;
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int irq_flags = 0;
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/*
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* Check for MMIO
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*/
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mmio = (( io_res->flags == IORESOURCE_MEM) &&
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(ctl_res->flags == IORESOURCE_MEM));
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/*
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* And the IRQ
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*/
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if (irq_res && irq_res->start > 0) {
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irq = irq_res->start;
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irq_flags = irq_res->flags;
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}
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/*
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* Now that that's out of the way, wire up the port..
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*/
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host = ata_host_alloc(dev, 1);
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if (!host)
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return -ENOMEM;
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ap = host->ports[0];
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ap->ops = &pata_platform_port_ops;
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ap->pio_mask = __pio_mask;
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ap->flags |= ATA_FLAG_SLAVE_POSS;
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/*
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* Use polling mode if there's no IRQ
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*/
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if (!irq) {
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ap->flags |= ATA_FLAG_PIO_POLLING;
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ata_port_desc(ap, "no IRQ, using PIO polling");
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}
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/*
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* Handle the MMIO case
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*/
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if (mmio) {
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ap->ioaddr.cmd_addr = devm_ioremap(dev, io_res->start,
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io_res->end - io_res->start + 1);
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ap->ioaddr.ctl_addr = devm_ioremap(dev, ctl_res->start,
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ctl_res->end - ctl_res->start + 1);
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} else {
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ap->ioaddr.cmd_addr = devm_ioport_map(dev, io_res->start,
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io_res->end - io_res->start + 1);
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ap->ioaddr.ctl_addr = devm_ioport_map(dev, ctl_res->start,
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ctl_res->end - ctl_res->start + 1);
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}
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if (!ap->ioaddr.cmd_addr || !ap->ioaddr.ctl_addr) {
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dev_err(dev, "failed to map IO/CTL base\n");
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return -ENOMEM;
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}
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ap->ioaddr.altstatus_addr = ap->ioaddr.ctl_addr;
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pata_platform_setup_port(&ap->ioaddr, ioport_shift);
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ata_port_desc(ap, "%s cmd 0x%llx ctl 0x%llx", mmio ? "mmio" : "ioport",
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(unsigned long long)io_res->start,
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(unsigned long long)ctl_res->start);
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/* activate */
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return ata_host_activate(host, irq, irq ? ata_interrupt : NULL,
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irq_flags, &pata_platform_sht);
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}
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EXPORT_SYMBOL_GPL(__pata_platform_probe);
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/**
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* __pata_platform_remove - unplug a platform interface
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* @dev: device
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*
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* A platform bus ATA device has been unplugged. Perform the needed
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* cleanup. Also called on module unload for any active devices.
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*/
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int __devexit __pata_platform_remove(struct device *dev)
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{
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struct ata_host *host = dev_get_drvdata(dev);
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ata_host_detach(host);
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return 0;
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}
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EXPORT_SYMBOL_GPL(__pata_platform_remove);
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static int __devinit pata_platform_probe(struct platform_device *pdev)
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{
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struct resource *io_res;
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struct resource *ctl_res;
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struct resource *irq_res;
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struct pata_platform_info *pp_info = pdev->dev.platform_data;
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/*
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* Simple resource validation ..
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*/
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if ((pdev->num_resources != 3) && (pdev->num_resources != 2)) {
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dev_err(&pdev->dev, "invalid number of resources\n");
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return -EINVAL;
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}
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/*
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* Get the I/O base first
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*/
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io_res = platform_get_resource(pdev, IORESOURCE_IO, 0);
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if (io_res == NULL) {
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io_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (unlikely(io_res == NULL))
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return -EINVAL;
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}
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/*
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* Then the CTL base
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*/
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ctl_res = platform_get_resource(pdev, IORESOURCE_IO, 1);
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if (ctl_res == NULL) {
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ctl_res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
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if (unlikely(ctl_res == NULL))
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return -EINVAL;
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}
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/*
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* And the IRQ
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*/
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irq_res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
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if (irq_res)
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irq_res->flags = pp_info ? pp_info->irq_flags : 0;
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return __pata_platform_probe(&pdev->dev, io_res, ctl_res, irq_res,
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pp_info ? pp_info->ioport_shift : 0,
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pio_mask);
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}
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static int __devexit pata_platform_remove(struct platform_device *pdev)
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{
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return __pata_platform_remove(&pdev->dev);
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}
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static struct platform_driver pata_platform_driver = {
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.probe = pata_platform_probe,
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.remove = __devexit_p(pata_platform_remove),
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.driver = {
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.name = DRV_NAME,
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.owner = THIS_MODULE,
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},
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};
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static int __init pata_platform_init(void)
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{
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return platform_driver_register(&pata_platform_driver);
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}
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static void __exit pata_platform_exit(void)
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{
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platform_driver_unregister(&pata_platform_driver);
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}
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module_init(pata_platform_init);
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module_exit(pata_platform_exit);
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module_param(pio_mask, int, 0);
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MODULE_AUTHOR("Paul Mundt");
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MODULE_DESCRIPTION("low-level driver for platform device ATA");
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MODULE_LICENSE("GPL");
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MODULE_VERSION(DRV_VERSION);
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