GNU Linux-libre 4.19.286-gnu1
[releases.git] / drivers / usb / wusbcore / reservation.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * WUSB cluster reservation management
4  *
5  * Copyright (C) 2007 Cambridge Silicon Radio Ltd.
6  */
7 #include <linux/kernel.h>
8 #include <linux/uwb.h>
9
10 #include "wusbhc.h"
11
12 /*
13  * WUSB cluster reservations are multicast reservations with the
14  * broadcast cluster ID (BCID) as the target DevAddr.
15  *
16  * FIXME: consider adjusting the reservation depending on what devices
17  * are attached.
18  */
19
20 static int wusbhc_bwa_set(struct wusbhc *wusbhc, u8 stream,
21         const struct uwb_mas_bm *mas)
22 {
23         if (mas == NULL)
24                 mas = &uwb_mas_bm_zero;
25         return wusbhc->bwa_set(wusbhc, stream, mas);
26 }
27
28 /**
29  * wusbhc_rsv_complete_cb - WUSB HC reservation complete callback
30  * @rsv:    the reservation
31  *
32  * Either set or clear the HC's view of the reservation.
33  *
34  * FIXME: when a reservation is denied the HC should be stopped.
35  */
36 static void wusbhc_rsv_complete_cb(struct uwb_rsv *rsv)
37 {
38         struct wusbhc *wusbhc = rsv->pal_priv;
39         struct device *dev = wusbhc->dev;
40         struct uwb_mas_bm mas;
41
42         dev_dbg(dev, "%s: state = %d\n", __func__, rsv->state);
43         switch (rsv->state) {
44         case UWB_RSV_STATE_O_ESTABLISHED:
45                 uwb_rsv_get_usable_mas(rsv, &mas);
46                 dev_dbg(dev, "established reservation: %*pb\n",
47                         UWB_NUM_MAS, mas.bm);
48                 wusbhc_bwa_set(wusbhc, rsv->stream, &mas);
49                 break;
50         case UWB_RSV_STATE_NONE:
51                 dev_dbg(dev, "removed reservation\n");
52                 wusbhc_bwa_set(wusbhc, 0, NULL);
53                 break;
54         default:
55                 dev_dbg(dev, "unexpected reservation state: %d\n", rsv->state);
56                 break;
57         }
58 }
59
60
61 /**
62  * wusbhc_rsv_establish - establish a reservation for the cluster
63  * @wusbhc: the WUSB HC requesting a bandwidth reservation
64  */
65 int wusbhc_rsv_establish(struct wusbhc *wusbhc)
66 {
67         struct uwb_rc *rc = wusbhc->uwb_rc;
68         struct uwb_rsv *rsv;
69         struct uwb_dev_addr bcid;
70         int ret;
71
72         if (rc == NULL)
73                 return -ENODEV;
74
75         rsv = uwb_rsv_create(rc, wusbhc_rsv_complete_cb, wusbhc);
76         if (rsv == NULL)
77                 return -ENOMEM;
78
79         bcid.data[0] = wusbhc->cluster_id;
80         bcid.data[1] = 0;
81
82         rsv->target.type = UWB_RSV_TARGET_DEVADDR;
83         rsv->target.devaddr = bcid;
84         rsv->type = UWB_DRP_TYPE_PRIVATE;
85         rsv->max_mas = 256; /* try to get as much as possible */
86         rsv->min_mas = 15;  /* one MAS per zone */
87         rsv->max_interval = 1; /* max latency is one zone */
88         rsv->is_multicast = true;
89
90         ret = uwb_rsv_establish(rsv);
91         if (ret == 0)
92                 wusbhc->rsv = rsv;
93         else
94                 uwb_rsv_destroy(rsv);
95         return ret;
96 }
97
98
99 /**
100  * wusbhc_rsv_terminate - terminate the cluster reservation
101  * @wusbhc: the WUSB host whose reservation is to be terminated
102  */
103 void wusbhc_rsv_terminate(struct wusbhc *wusbhc)
104 {
105         if (wusbhc->rsv) {
106                 uwb_rsv_terminate(wusbhc->rsv);
107                 uwb_rsv_destroy(wusbhc->rsv);
108                 wusbhc->rsv = NULL;
109         }
110 }