drivers/gpu/host1x/channel.c

   1 /*
   2  * Tegra host1x Channel
   3  *
   4  * Copyright (c) 2010-2013, NVIDIA Corporation.
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms and conditions of the GNU General Public License,
   8  * version 2, as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include <linux/slab.h>
  20 #include <linux/module.h>
  21
  22 #include "channel.h"
  23 #include "dev.h"
  24 #include "job.h"
  25
  26 /* Constructor for the host1x device list */
  27 int host1x_channel_list_init(struct host1x_channel_list *chlist,
  28                              unsigned int num_channels)
  29 {
  30         chlist->channels = kcalloc(num_channels, sizeof(struct host1x_channel),
  31                                    GFP_KERNEL);
  32         if (!chlist->channels)
  33                 return -ENOMEM;
  34
  35         chlist->allocated_channels =
  36                 kcalloc(BITS_TO_LONGS(num_channels), sizeof(unsigned long),
  37                         GFP_KERNEL);
  38         if (!chlist->allocated_channels) {
  39                 kfree(chlist->channels);
  40                 return -ENOMEM;
  41         }
  42
  43         bitmap_zero(chlist->allocated_channels, num_channels);
  44
  45         return 0;
  46 }
  47
  48 void host1x_channel_list_free(struct host1x_channel_list *chlist)
  49 {
  50         kfree(chlist->allocated_channels);
  51         kfree(chlist->channels);
  52 }
  53
  54 int host1x_job_submit(struct host1x_job *job)
  55 {
  56         struct host1x *host = dev_get_drvdata(job->channel->dev->parent);
  57
  58         return host1x_hw_channel_submit(host, job);
  59 }
  60 EXPORT_SYMBOL(host1x_job_submit);
  61
  62 struct host1x_channel *host1x_channel_get(struct host1x_channel *channel)
  63 {
  64         kref_get(&channel->refcount);
  65
  66         return channel;
  67 }
  68 EXPORT_SYMBOL(host1x_channel_get);
  69
  70 /**
  71  * host1x_channel_get_index() - Attempt to get channel reference by index
  72  * @host: Host1x device object
  73  * @index: Index of channel
  74  *
  75  * If channel number @index is currently allocated, increase its refcount
  76  * and return a pointer to it. Otherwise, return NULL.
  77  */
  78 struct host1x_channel *host1x_channel_get_index(struct host1x *host,
  79                                                 unsigned int index)
  80 {
  81         struct host1x_channel *ch = &host->channel_list.channels[index];
  82
  83         if (!kref_get_unless_zero(&ch->refcount))
  84                 return NULL;
  85
  86         return ch;
  87 }
  88
  89 static void release_channel(struct kref *kref)
  90 {
  91         struct host1x_channel *channel =
  92                 container_of(kref, struct host1x_channel, refcount);
  93         struct host1x *host = dev_get_drvdata(channel->dev->parent);
  94         struct host1x_channel_list *chlist = &host->channel_list;
  95
  96         host1x_hw_cdma_stop(host, &channel->cdma);
  97         host1x_cdma_deinit(&channel->cdma);
  98
  99         clear_bit(channel->id, chlist->allocated_channels);
 100 }
 101
 102 void host1x_channel_put(struct host1x_channel *channel)
 103 {
 104         kref_put(&channel->refcount, release_channel);
 105 }
 106 EXPORT_SYMBOL(host1x_channel_put);
 107
 108 static struct host1x_channel *acquire_unused_channel(struct host1x *host)
 109 {
 110         struct host1x_channel_list *chlist = &host->channel_list;
 111         unsigned int max_channels = host->info->nb_channels;
 112         unsigned int index;
 113
 114         index = find_first_zero_bit(chlist->allocated_channels, max_channels);
 115         if (index >= max_channels) {
 116                 dev_err(host->dev, "failed to find free channel\n");
 117                 return NULL;
 118         }
 119
 120         chlist->channels[index].id = index;
 121
 122         set_bit(index, chlist->allocated_channels);
 123
 124         return &chlist->channels[index];
 125 }
 126
 127 /**
 128  * host1x_channel_request() - Allocate a channel
 129  * @device: Host1x unit this channel will be used to send commands to
 130  *
 131  * Allocates a new host1x channel for @device. If there are no free channels,
 132  * this will sleep until one becomes available. May return NULL if CDMA
 133  * initialization fails.
 134  */
 135 struct host1x_channel *host1x_channel_request(struct device *dev)
 136 {
 137         struct host1x *host = dev_get_drvdata(dev->parent);
 138         struct host1x_channel_list *chlist = &host->channel_list;
 139         struct host1x_channel *channel;
 140         int err;
 141
 142         channel = acquire_unused_channel(host);
 143         if (!channel)
 144                 return NULL;
 145
 146         kref_init(&channel->refcount);
 147         mutex_init(&channel->submitlock);
 148         channel->dev = dev;
 149
 150         err = host1x_hw_channel_init(host, channel, channel->id);
 151         if (err < 0)
 152                 goto fail;
 153
 154         err = host1x_cdma_init(&channel->cdma);
 155         if (err < 0)
 156                 goto fail;
 157
 158         return channel;
 159
 160 fail:
 161         clear_bit(channel->id, chlist->allocated_channels);
 162
 163         dev_err(dev, "failed to initialize channel\n");
 164
 165         return NULL;
 166 }
 167 EXPORT_SYMBOL(host1x_channel_request);