forked from luck/tmp_suning_uos_patched
54d3f8c63d
ACPI offers two methods that allow us to infer whether or not a USB port is removable. The _PLD method gives us information on whether the port is "user visible" or not. If that's not present then we can fall back to the _UPC method which tells us whether or not a port is connectable. Signed-off-by: Matthew Garrett <mjg@redhat.com> Signed-off-by: Lan Tianyu <tianyu.lan@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
118 lines
2.5 KiB
C
118 lines
2.5 KiB
C
/*
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* USB-ACPI glue code
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*
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* Copyright 2012 Red Hat <mjg@redhat.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation, version 2.
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*
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*/
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#include <linux/module.h>
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#include <linux/usb.h>
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#include <linux/device.h>
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/acpi.h>
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#include <linux/pci.h>
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#include <acpi/acpi_bus.h>
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#include "usb.h"
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static int usb_acpi_check_upc(struct usb_device *udev, acpi_handle handle)
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{
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acpi_status status;
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struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
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union acpi_object *upc;
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int ret = 0;
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status = acpi_evaluate_object(handle, "_UPC", NULL, &buffer);
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if (ACPI_FAILURE(status))
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return -ENODEV;
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upc = buffer.pointer;
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if (!upc || (upc->type != ACPI_TYPE_PACKAGE)
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|| upc->package.count != 4) {
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ret = -EINVAL;
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goto out;
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}
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if (upc->package.elements[0].integer.value)
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udev->removable = USB_DEVICE_REMOVABLE;
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else
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udev->removable = USB_DEVICE_FIXED;
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out:
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kfree(upc);
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return ret;
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}
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static int usb_acpi_check_pld(struct usb_device *udev, acpi_handle handle)
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{
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acpi_status status;
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struct acpi_pld pld;
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status = acpi_get_physical_device_location(handle, &pld);
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if (ACPI_FAILURE(status))
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return -ENODEV;
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if (pld.user_visible)
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udev->removable = USB_DEVICE_REMOVABLE;
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else
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udev->removable = USB_DEVICE_FIXED;
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return 0;
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}
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static int usb_acpi_find_device(struct device *dev, acpi_handle *handle)
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{
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struct usb_device *udev;
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struct device *parent;
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acpi_handle *parent_handle;
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if (!is_usb_device(dev))
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return -ENODEV;
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udev = to_usb_device(dev);
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parent = dev->parent;
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parent_handle = DEVICE_ACPI_HANDLE(parent);
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if (!parent_handle)
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return -ENODEV;
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*handle = acpi_get_child(parent_handle, udev->portnum);
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if (!*handle)
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return -ENODEV;
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/*
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* PLD will tell us whether a port is removable to the user or
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* not. If we don't get an answer from PLD (it's not present
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* or it's malformed) then try to infer it from UPC. If a
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* device isn't connectable then it's probably not removable.
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*/
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if (usb_acpi_check_pld(udev, *handle) != 0)
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usb_acpi_check_upc(udev, *handle);
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return 0;
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}
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static struct acpi_bus_type usb_acpi_bus = {
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.bus = &usb_bus_type,
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.find_bridge = NULL,
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.find_device = usb_acpi_find_device,
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};
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int usb_acpi_register(void)
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{
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return register_acpi_bus_type(&usb_acpi_bus);
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}
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void usb_acpi_unregister(void)
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{
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unregister_acpi_bus_type(&usb_acpi_bus);
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}
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