1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Tegra host1x Channel
4  *
5  * Copyright (c) 2010-2013, NVIDIA Corporation.
6  */
7 
8 #include <linux/slab.h>
9 #include <linux/module.h>
10 
11 #include "channel.h"
12 #include "dev.h"
13 #include "job.h"
14 
15 /* Constructor for the host1x device list */
host1x_channel_list_init(struct host1x_channel_list * chlist,unsigned int num_channels)16 int host1x_channel_list_init(struct host1x_channel_list *chlist,
17 			     unsigned int num_channels)
18 {
19 	chlist->channels = kcalloc(num_channels, sizeof(struct host1x_channel),
20 				   GFP_KERNEL);
21 	if (!chlist->channels)
22 		return -ENOMEM;
23 
24 	chlist->allocated_channels = bitmap_zalloc(num_channels, GFP_KERNEL);
25 	if (!chlist->allocated_channels) {
26 		kfree(chlist->channels);
27 		return -ENOMEM;
28 	}
29 
30 	return 0;
31 }
32 
host1x_channel_list_free(struct host1x_channel_list * chlist)33 void host1x_channel_list_free(struct host1x_channel_list *chlist)
34 {
35 	bitmap_free(chlist->allocated_channels);
36 	kfree(chlist->channels);
37 }
38 
host1x_job_submit(struct host1x_job * job)39 int host1x_job_submit(struct host1x_job *job)
40 {
41 	struct host1x *host = dev_get_drvdata(job->channel->dev->parent);
42 
43 	return host1x_hw_channel_submit(host, job);
44 }
45 EXPORT_SYMBOL(host1x_job_submit);
46 
host1x_channel_get(struct host1x_channel * channel)47 struct host1x_channel *host1x_channel_get(struct host1x_channel *channel)
48 {
49 	kref_get(&channel->refcount);
50 
51 	return channel;
52 }
53 EXPORT_SYMBOL(host1x_channel_get);
54 
55 /**
56  * host1x_channel_get_index() - Attempt to get channel reference by index
57  * @host: Host1x device object
58  * @index: Index of channel
59  *
60  * If channel number @index is currently allocated, increase its refcount
61  * and return a pointer to it. Otherwise, return NULL.
62  */
host1x_channel_get_index(struct host1x * host,unsigned int index)63 struct host1x_channel *host1x_channel_get_index(struct host1x *host,
64 						unsigned int index)
65 {
66 	struct host1x_channel *ch = &host->channel_list.channels[index];
67 
68 	if (!kref_get_unless_zero(&ch->refcount))
69 		return NULL;
70 
71 	return ch;
72 }
73 
host1x_channel_stop(struct host1x_channel * channel)74 void host1x_channel_stop(struct host1x_channel *channel)
75 {
76 	struct host1x *host = dev_get_drvdata(channel->dev->parent);
77 
78 	host1x_hw_cdma_stop(host, &channel->cdma);
79 }
80 EXPORT_SYMBOL(host1x_channel_stop);
81 
release_channel(struct kref * kref)82 static void release_channel(struct kref *kref)
83 {
84 	struct host1x_channel *channel =
85 		container_of(kref, struct host1x_channel, refcount);
86 	struct host1x *host = dev_get_drvdata(channel->dev->parent);
87 	struct host1x_channel_list *chlist = &host->channel_list;
88 
89 	host1x_hw_cdma_stop(host, &channel->cdma);
90 	host1x_cdma_deinit(&channel->cdma);
91 
92 	clear_bit(channel->id, chlist->allocated_channels);
93 }
94 
host1x_channel_put(struct host1x_channel * channel)95 void host1x_channel_put(struct host1x_channel *channel)
96 {
97 	kref_put(&channel->refcount, release_channel);
98 }
99 EXPORT_SYMBOL(host1x_channel_put);
100 
acquire_unused_channel(struct host1x * host)101 static struct host1x_channel *acquire_unused_channel(struct host1x *host)
102 {
103 	struct host1x_channel_list *chlist = &host->channel_list;
104 	unsigned int max_channels = host->info->nb_channels;
105 	unsigned int index;
106 
107 	index = find_first_zero_bit(chlist->allocated_channels, max_channels);
108 	if (index >= max_channels) {
109 		dev_err(host->dev, "failed to find free channel\n");
110 		return NULL;
111 	}
112 
113 	chlist->channels[index].id = index;
114 
115 	set_bit(index, chlist->allocated_channels);
116 
117 	return &chlist->channels[index];
118 }
119 
120 /**
121  * host1x_channel_request() - Allocate a channel
122  * @client: Host1x client this channel will be used to send commands to
123  *
124  * Allocates a new host1x channel for @client. May return NULL if CDMA
125  * initialization fails.
126  */
host1x_channel_request(struct host1x_client * client)127 struct host1x_channel *host1x_channel_request(struct host1x_client *client)
128 {
129 	struct host1x *host = dev_get_drvdata(client->dev->parent);
130 	struct host1x_channel_list *chlist = &host->channel_list;
131 	struct host1x_channel *channel;
132 	int err;
133 
134 	channel = acquire_unused_channel(host);
135 	if (!channel)
136 		return NULL;
137 
138 	kref_init(&channel->refcount);
139 	mutex_init(&channel->submitlock);
140 	channel->client = client;
141 	channel->dev = client->dev;
142 
143 	err = host1x_hw_channel_init(host, channel, channel->id);
144 	if (err < 0)
145 		goto fail;
146 
147 	err = host1x_cdma_init(&channel->cdma);
148 	if (err < 0)
149 		goto fail;
150 
151 	return channel;
152 
153 fail:
154 	clear_bit(channel->id, chlist->allocated_channels);
155 
156 	dev_err(client->dev, "failed to initialize channel\n");
157 
158 	return NULL;
159 }
160 EXPORT_SYMBOL(host1x_channel_request);
161