![Alan Stern](/assets/img/avatar_default.png)
This patch (as1069c) changes the way OHCI root-hub status-change interrupts are enabled. Currently a special HCD method, hub_irq_enable(), is called when the hub driver is finished using a root hub. This approach turns out to be subject to races, resulting in unnecessary polling. The patch does away with the method entirely. Instead, the driver automatically enables the RHSC interrupt when no more status changes are present. This scheme is safe with controllers using level-triggered semantics for their interrupt flags. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
254 lines
6 KiB
C
254 lines
6 KiB
C
/*
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* OHCI HCD (Host Controller Driver) for USB.
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*
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* (C) Copyright 1999 Roman Weissgaerber <weissg@vienna.at>
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* (C) Copyright 2000-2002 David Brownell <dbrownell@users.sourceforge.net>
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* (C) Copyright 2002 Hewlett-Packard Company
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*
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* Bus Glue for Sharp LH7A404
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*
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* Written by Christopher Hoover <ch@hpl.hp.com>
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* Based on fragments of previous driver by Russell King et al.
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*
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* Modified for LH7A404 from ohci-sa1111.c
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* by Durgesh Pattamatta <pattamattad@sharpsec.com>
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*
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* This file is licenced under the GPL.
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*/
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#include <linux/platform_device.h>
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#include <linux/signal.h>
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#include <mach/hardware.h>
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extern int usb_disabled(void);
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/*-------------------------------------------------------------------------*/
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static void lh7a404_start_hc(struct platform_device *dev)
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{
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printk(KERN_DEBUG __FILE__
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": starting LH7A404 OHCI USB Controller\n");
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/*
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* Now, carefully enable the USB clock, and take
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* the USB host controller out of reset.
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*/
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CSC_PWRCNT |= CSC_PWRCNT_USBH_EN; /* Enable clock */
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udelay(1000);
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USBH_CMDSTATUS = OHCI_HCR;
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printk(KERN_DEBUG __FILE__
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": Clock to USB host has been enabled \n");
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}
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static void lh7a404_stop_hc(struct platform_device *dev)
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{
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printk(KERN_DEBUG __FILE__
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": stopping LH7A404 OHCI USB Controller\n");
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CSC_PWRCNT &= ~CSC_PWRCNT_USBH_EN; /* Disable clock */
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}
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/*-------------------------------------------------------------------------*/
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/* configure so an HC device and id are always provided */
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/* always called with process context; sleeping is OK */
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/**
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* usb_hcd_lh7a404_probe - initialize LH7A404-based HCDs
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* Context: !in_interrupt()
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*
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* Allocates basic resources for this USB host controller, and
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* then invokes the start() method for the HCD associated with it
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* through the hotplug entry's driver_data.
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*
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*/
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int usb_hcd_lh7a404_probe (const struct hc_driver *driver,
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struct platform_device *dev)
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{
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int retval;
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struct usb_hcd *hcd;
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if (dev->resource[1].flags != IORESOURCE_IRQ) {
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pr_debug("resource[1] is not IORESOURCE_IRQ");
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return -ENOMEM;
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}
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hcd = usb_create_hcd(driver, &dev->dev, "lh7a404");
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if (!hcd)
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return -ENOMEM;
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hcd->rsrc_start = dev->resource[0].start;
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hcd->rsrc_len = dev->resource[0].end - dev->resource[0].start + 1;
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if (!request_mem_region(hcd->rsrc_start, hcd->rsrc_len, hcd_name)) {
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pr_debug("request_mem_region failed");
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retval = -EBUSY;
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goto err1;
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}
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hcd->regs = ioremap(hcd->rsrc_start, hcd->rsrc_len);
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if (!hcd->regs) {
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pr_debug("ioremap failed");
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retval = -ENOMEM;
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goto err2;
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}
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lh7a404_start_hc(dev);
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ohci_hcd_init(hcd_to_ohci(hcd));
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retval = usb_add_hcd(hcd, dev->resource[1].start, IRQF_DISABLED);
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if (retval == 0)
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return retval;
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lh7a404_stop_hc(dev);
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iounmap(hcd->regs);
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err2:
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release_mem_region(hcd->rsrc_start, hcd->rsrc_len);
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err1:
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usb_put_hcd(hcd);
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return retval;
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}
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/* may be called without controller electrically present */
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/* may be called with controller, bus, and devices active */
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/**
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* usb_hcd_lh7a404_remove - shutdown processing for LH7A404-based HCDs
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* @dev: USB Host Controller being removed
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* Context: !in_interrupt()
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*
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* Reverses the effect of usb_hcd_lh7a404_probe(), first invoking
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* the HCD's stop() method. It is always called from a thread
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* context, normally "rmmod", "apmd", or something similar.
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*
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*/
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void usb_hcd_lh7a404_remove (struct usb_hcd *hcd, struct platform_device *dev)
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{
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usb_remove_hcd(hcd);
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lh7a404_stop_hc(dev);
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iounmap(hcd->regs);
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release_mem_region(hcd->rsrc_start, hcd->rsrc_len);
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usb_put_hcd(hcd);
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}
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/*-------------------------------------------------------------------------*/
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static int __devinit
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ohci_lh7a404_start (struct usb_hcd *hcd)
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{
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struct ohci_hcd *ohci = hcd_to_ohci (hcd);
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int ret;
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ohci_dbg (ohci, "ohci_lh7a404_start, ohci:%p", ohci);
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if ((ret = ohci_init(ohci)) < 0)
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return ret;
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if ((ret = ohci_run (ohci)) < 0) {
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err ("can't start %s", hcd->self.bus_name);
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ohci_stop (hcd);
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return ret;
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}
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return 0;
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}
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/*-------------------------------------------------------------------------*/
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static const struct hc_driver ohci_lh7a404_hc_driver = {
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.description = hcd_name,
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.product_desc = "LH7A404 OHCI",
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.hcd_priv_size = sizeof(struct ohci_hcd),
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/*
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* generic hardware linkage
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*/
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.irq = ohci_irq,
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.flags = HCD_USB11 | HCD_MEMORY,
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/*
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* basic lifecycle operations
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*/
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.start = ohci_lh7a404_start,
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.stop = ohci_stop,
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.shutdown = ohci_shutdown,
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/*
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* managing i/o requests and associated device resources
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*/
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.urb_enqueue = ohci_urb_enqueue,
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.urb_dequeue = ohci_urb_dequeue,
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.endpoint_disable = ohci_endpoint_disable,
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/*
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* scheduling support
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*/
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.get_frame_number = ohci_get_frame,
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/*
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* root hub support
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*/
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.hub_status_data = ohci_hub_status_data,
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.hub_control = ohci_hub_control,
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#ifdef CONFIG_PM
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.bus_suspend = ohci_bus_suspend,
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.bus_resume = ohci_bus_resume,
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#endif
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.start_port_reset = ohci_start_port_reset,
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};
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/*-------------------------------------------------------------------------*/
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static int ohci_hcd_lh7a404_drv_probe(struct platform_device *pdev)
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{
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int ret;
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pr_debug ("In ohci_hcd_lh7a404_drv_probe");
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if (usb_disabled())
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return -ENODEV;
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ret = usb_hcd_lh7a404_probe(&ohci_lh7a404_hc_driver, pdev);
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return ret;
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}
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static int ohci_hcd_lh7a404_drv_remove(struct platform_device *pdev)
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{
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struct usb_hcd *hcd = platform_get_drvdata(pdev);
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usb_hcd_lh7a404_remove(hcd, pdev);
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return 0;
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}
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/*TBD*/
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/*static int ohci_hcd_lh7a404_drv_suspend(struct platform_device *dev)
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{
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struct usb_hcd *hcd = platform_get_drvdata(dev);
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return 0;
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}
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static int ohci_hcd_lh7a404_drv_resume(struct platform_device *dev)
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{
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struct usb_hcd *hcd = platform_get_drvdata(dev);
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return 0;
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}
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*/
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static struct platform_driver ohci_hcd_lh7a404_driver = {
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.probe = ohci_hcd_lh7a404_drv_probe,
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.remove = ohci_hcd_lh7a404_drv_remove,
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.shutdown = usb_hcd_platform_shutdown,
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/*.suspend = ohci_hcd_lh7a404_drv_suspend, */
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/*.resume = ohci_hcd_lh7a404_drv_resume, */
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.driver = {
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.name = "lh7a404-ohci",
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.owner = THIS_MODULE,
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},
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};
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MODULE_ALIAS("platform:lh7a404-ohci");
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