drivers/staging/uwb/scan.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Ultra Wide Band
   4  * Scanning management
   5  *
   6  * Copyright (C) 2005-2006 Intel Corporation
   7  * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
   8  *
   9  * FIXME: docs
  10  * FIXME: there are issues here on how BEACON and SCAN on USB RCI deal
  11  *        with each other. Currently seems that START_BEACON while
  12  *        SCAN_ONLY will cancel the scan, so we need to update the
  13  *        state here. Clarification request sent by email on
  14  *        10/05/2005.
  15  *        10/28/2005 No clear answer heard--maybe we'll hack the API
  16  *                   so that when we start beaconing, if the HC is
  17  *                   scanning in a mode not compatible with beaconing
  18  *                   we just fail.
  19  */
  20
  21 #include <linux/device.h>
  22 #include <linux/err.h>
  23 #include <linux/slab.h>
  24 #include <linux/stat.h>
  25 #include "uwb-internal.h"
  26
  27
  28 /**
  29  * Start/stop scanning in a radio controller
  30  *
  31  * @rc:      UWB Radio Controller
  32  * @channel: Channel to scan; encodings in WUSB1.0[Table 5.12]
  33  * @type:    Type of scanning to do.
  34  * @bpst_offset: value at which to start scanning (if type ==
  35  *                UWB_SCAN_ONLY_STARTTIME)
  36  * @returns: 0 if ok, < 0 errno code on error
  37  *
  38  * We put the command on kmalloc'ed memory as some arches cannot do
  39  * USB from the stack. The reply event is copied from an stage buffer,
  40  * so it can be in the stack. See WUSB1.0[8.6.2.4] for more details.
  41  */
  42 int uwb_rc_scan(struct uwb_rc *rc,
  43                 unsigned channel, enum uwb_scan_type type,
  44                 unsigned bpst_offset)
  45 {
  46         int result;
  47         struct uwb_rc_cmd_scan *cmd;
  48         struct uwb_rc_evt_confirm reply;
  49
  50         result = -ENOMEM;
  51         cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
  52         if (cmd == NULL)
  53                 goto error_kzalloc;
  54         mutex_lock(&rc->uwb_dev.mutex);
  55         cmd->rccb.bCommandType = UWB_RC_CET_GENERAL;
  56         cmd->rccb.wCommand = cpu_to_le16(UWB_RC_CMD_SCAN);
  57         cmd->bChannelNumber = channel;
  58         cmd->bScanState = type;
  59         cmd->wStartTime = cpu_to_le16(bpst_offset);
  60         reply.rceb.bEventType = UWB_RC_CET_GENERAL;
  61         reply.rceb.wEvent = UWB_RC_CMD_SCAN;
  62         result = uwb_rc_cmd(rc, "SCAN", &cmd->rccb, sizeof(*cmd),
  63                             &reply.rceb, sizeof(reply));
  64         if (result < 0)
  65                 goto error_cmd;
  66         if (reply.bResultCode != UWB_RC_RES_SUCCESS) {
  67                 dev_err(&rc->uwb_dev.dev,
  68                         "SCAN: command execution failed: %s (%d)\n",
  69                         uwb_rc_strerror(reply.bResultCode), reply.bResultCode);
  70                 result = -EIO;
  71                 goto error_cmd;
  72         }
  73         rc->scanning = channel;
  74         rc->scan_type = type;
  75 error_cmd:
  76         mutex_unlock(&rc->uwb_dev.mutex);
  77         kfree(cmd);
  78 error_kzalloc:
  79         return result;
  80 }
  81
  82 /*
  83  * Print scanning state
  84  */
  85 static ssize_t uwb_rc_scan_show(struct device *dev,
  86                                 struct device_attribute *attr, char *buf)
  87 {
  88         struct uwb_dev *uwb_dev = to_uwb_dev(dev);
  89         struct uwb_rc *rc = uwb_dev->rc;
  90         ssize_t result;
  91
  92         mutex_lock(&rc->uwb_dev.mutex);
  93         result = sprintf(buf, "%d %d\n", rc->scanning, rc->scan_type);
  94         mutex_unlock(&rc->uwb_dev.mutex);
  95         return result;
  96 }
  97
  98 /*
  99  *
 100  */
 101 static ssize_t uwb_rc_scan_store(struct device *dev,
 102                                  struct device_attribute *attr,
 103                                  const char *buf, size_t size)
 104 {
 105         struct uwb_dev *uwb_dev = to_uwb_dev(dev);
 106         struct uwb_rc *rc = uwb_dev->rc;
 107         unsigned channel;
 108         unsigned type;
 109         unsigned bpst_offset = 0;
 110         ssize_t result = -EINVAL;
 111
 112         result = sscanf(buf, "%u %u %u\n", &channel, &type, &bpst_offset);
 113         if (result >= 2 && type < UWB_SCAN_TOP)
 114                 result = uwb_rc_scan(rc, channel, type, bpst_offset);
 115
 116         return result < 0 ? result : size;
 117 }
 118
 119 /** Radio Control sysfs interface (declaration) */
 120 DEVICE_ATTR(scan, S_IRUGO | S_IWUSR, uwb_rc_scan_show, uwb_rc_scan_store);