![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>
144 lines
3.3 KiB
C
144 lines
3.3 KiB
C
/*
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* OHCI HCD (Host Controller Driver) for USB.
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*
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* Copyright (C) 2008 Renesas Solutions Corp.
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*
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* Author : Yoshihiro Shimoda <shimoda.yoshihiro@renesas.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*/
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#include <linux/platform_device.h>
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static int ohci_sh_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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ohci_hcd_init(ohci);
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ohci_init(ohci);
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ohci_run(ohci);
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hcd->state = HC_STATE_RUNNING;
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return 0;
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}
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static const struct hc_driver ohci_sh_hc_driver = {
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.description = hcd_name,
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.product_desc = "SuperH 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_sh_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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#define resource_len(r) (((r)->end - (r)->start) + 1)
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static int ohci_hcd_sh_probe(struct platform_device *pdev)
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{
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struct resource *res = NULL;
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struct usb_hcd *hcd = NULL;
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int irq = -1;
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int ret;
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if (usb_disabled())
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return -ENODEV;
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (!res) {
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err("platform_get_resource error.");
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return -ENODEV;
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}
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irq = platform_get_irq(pdev, 0);
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if (irq < 0) {
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err("platform_get_irq error.");
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return -ENODEV;
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}
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/* initialize hcd */
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hcd = usb_create_hcd(&ohci_sh_hc_driver, &pdev->dev, (char *)hcd_name);
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if (!hcd) {
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err("Failed to create hcd");
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return -ENOMEM;
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}
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hcd->regs = (void __iomem *)res->start;
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hcd->rsrc_start = res->start;
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hcd->rsrc_len = resource_len(res);
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ret = usb_add_hcd(hcd, irq, IRQF_DISABLED);
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if (ret != 0) {
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err("Failed to add hcd");
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usb_put_hcd(hcd);
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return ret;
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}
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return ret;
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}
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static int ohci_hcd_sh_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_remove_hcd(hcd);
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usb_put_hcd(hcd);
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return 0;
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}
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static struct platform_driver ohci_hcd_sh_driver = {
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.probe = ohci_hcd_sh_probe,
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.remove = ohci_hcd_sh_remove,
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.shutdown = usb_hcd_platform_shutdown,
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.driver = {
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.name = "sh_ohci",
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.owner = THIS_MODULE,
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},
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};
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MODULE_ALIAS("platform:sh_ohci");
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