drivers/staging/wimax/op-reset.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Linux WiMAX
   4  * Implement and export a method for resetting a WiMAX device
   5  *
   6  * Copyright (C) 2008 Intel Corporation <linux-wimax@intel.com>
   7  * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
   8  *
   9  * This implements a simple synchronous call to reset a WiMAX device.
  10  *
  11  * Resets aim at being warm, keeping the device handles active;
  12  * however, when that fails, it falls back to a cold reset (that will
  13  * disconnect and reconnect the device).
  14  */
  15
  16 #include "net-wimax.h"
  17 #include <net/genetlink.h>
  18 #include "linux-wimax.h"
  19 #include <linux/security.h>
  20 #include <linux/export.h>
  21 #include "wimax-internal.h"
  22
  23 #define D_SUBMODULE op_reset
  24 #include "debug-levels.h"
  25
  26
  27 /**
  28  * wimax_reset - Reset a WiMAX device
  29  *
  30  * @wimax_dev: WiMAX device descriptor
  31  *
  32  * Returns:
  33  *
  34  * %0 if ok and a warm reset was done (the device still exists in
  35  * the system).
  36  *
  37  * -%ENODEV if a cold/bus reset had to be done (device has
  38  * disconnected and reconnected, so current handle is not valid
  39  * any more).
  40  *
  41  * -%EINVAL if the device is not even registered.
  42  *
  43  * Any other negative error code shall be considered as
  44  * non-recoverable.
  45  *
  46  * Description:
  47  *
  48  * Called when wanting to reset the device for any reason. Device is
  49  * taken back to power on status.
  50  *
  51  * This call blocks; on successful return, the device has completed the
  52  * reset process and is ready to operate.
  53  */
  54 int wimax_reset(struct wimax_dev *wimax_dev)
  55 {
  56         int result = -EINVAL;
  57         struct device *dev = wimax_dev_to_dev(wimax_dev);
  58         enum wimax_st state;
  59
  60         might_sleep();
  61         d_fnstart(3, dev, "(wimax_dev %p)\n", wimax_dev);
  62         mutex_lock(&wimax_dev->mutex);
  63         dev_hold(wimax_dev->net_dev);
  64         state = wimax_dev->state;
  65         mutex_unlock(&wimax_dev->mutex);
  66
  67         if (state >= WIMAX_ST_DOWN) {
  68                 mutex_lock(&wimax_dev->mutex_reset);
  69                 result = wimax_dev->op_reset(wimax_dev);
  70                 mutex_unlock(&wimax_dev->mutex_reset);
  71         }
  72         dev_put(wimax_dev->net_dev);
  73
  74         d_fnend(3, dev, "(wimax_dev %p) = %d\n", wimax_dev, result);
  75         return result;
  76 }
  77 EXPORT_SYMBOL(wimax_reset);
  78
  79
  80 /*
  81  * Exporting to user space over generic netlink
  82  *
  83  * Parse the reset command from user space, return error code.
  84  *
  85  * No attributes.
  86  */
  87 int wimax_gnl_doit_reset(struct sk_buff *skb, struct genl_info *info)
  88 {
  89         int result, ifindex;
  90         struct wimax_dev *wimax_dev;
  91
  92         d_fnstart(3, NULL, "(skb %p info %p)\n", skb, info);
  93         result = -ENODEV;
  94         if (info->attrs[WIMAX_GNL_RESET_IFIDX] == NULL) {
  95                 pr_err("WIMAX_GNL_OP_RFKILL: can't find IFIDX attribute\n");
  96                 goto error_no_wimax_dev;
  97         }
  98         ifindex = nla_get_u32(info->attrs[WIMAX_GNL_RESET_IFIDX]);
  99         wimax_dev = wimax_dev_get_by_genl_info(info, ifindex);
 100         if (wimax_dev == NULL)
 101                 goto error_no_wimax_dev;
 102         /* Execute the operation and send the result back to user space */
 103         result = wimax_reset(wimax_dev);
 104         dev_put(wimax_dev->net_dev);
 105 error_no_wimax_dev:
 106         d_fnend(3, NULL, "(skb %p info %p) = %d\n", skb, info, result);
 107         return result;
 108 }