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 */
 16int 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
 33void host1x_channel_list_free(struct host1x_channel_list *chlist)
 34{
 35	bitmap_free(chlist->allocated_channels);
 36	kfree(chlist->channels);
 37}
 38
 39int 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}
 45EXPORT_SYMBOL(host1x_job_submit);
 46
 47struct host1x_channel *host1x_channel_get(struct host1x_channel *channel)
 48{
 49	kref_get(&channel->refcount);
 50
 51	return channel;
 52}
 53EXPORT_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 */
 63struct 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
 74void 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}
 80EXPORT_SYMBOL(host1x_channel_stop);
 81
 82static 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
 95void host1x_channel_put(struct host1x_channel *channel)
 96{
 97	kref_put(&channel->refcount, release_channel);
 98}
 99EXPORT_SYMBOL(host1x_channel_put);
100
101static 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 */
127struct 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
153fail:
154	clear_bit(channel->id, chlist->allocated_channels);
155
156	dev_err(client->dev, "failed to initialize channel\n");
157
158	return NULL;
159}
160EXPORT_SYMBOL(host1x_channel_request);