drivers/gpu/host1x/context.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2021, NVIDIA Corporation.
   4  */
   5
   6 #include <linux/device.h>
   7 #include <linux/kref.h>
   8 #include <linux/of.h>
   9 #include <linux/of_device.h>
  10 #include <linux/pid.h>
  11 #include <linux/slab.h>
  12
  13 #include "context.h"
  14 #include "dev.h"
  15
  16 static void host1x_memory_context_release(struct device *dev)
  17 {
  18         /* context device is freed in host1x_memory_context_list_free() */
  19 }
  20
  21 int host1x_memory_context_list_init(struct host1x *host1x)
  22 {
  23         struct host1x_memory_context_list *cdl = &host1x->context_list;
  24         struct device_node *node = host1x->dev->of_node;
  25         struct host1x_memory_context *ctx;
  26         unsigned int i;
  27         int err;
  28
  29         cdl->devs = NULL;
  30         cdl->len = 0;
  31         mutex_init(&cdl->lock);
  32
  33         err = of_property_count_u32_elems(node, "iommu-map");
  34         if (err < 0)
  35                 return 0;
  36
  37         cdl->len = err / 4;
  38         cdl->devs = kcalloc(cdl->len, sizeof(*cdl->devs), GFP_KERNEL);
  39         if (!cdl->devs)
  40                 return -ENOMEM;
  41
  42         for (i = 0; i < cdl->len; i++) {
  43                 ctx = &cdl->devs[i];
  44
  45                 ctx->host = host1x;
  46
  47                 device_initialize(&ctx->dev);
  48
  49                 /*
  50                  * Due to an issue with T194 NVENC, only 38 bits can be used.
  51                  * Anyway, 256GiB of IOVA ought to be enough for anyone.
  52                  */
  53                 ctx->dma_mask = DMA_BIT_MASK(38);
  54                 ctx->dev.dma_mask = &ctx->dma_mask;
  55                 ctx->dev.coherent_dma_mask = ctx->dma_mask;
  56                 dev_set_name(&ctx->dev, "host1x-ctx.%d", i);
  57                 ctx->dev.bus = &host1x_context_device_bus_type;
  58                 ctx->dev.parent = host1x->dev;
  59                 ctx->dev.release = host1x_memory_context_release;
  60
  61                 ctx->dev.dma_parms = &ctx->dma_parms;
  62                 dma_set_max_seg_size(&ctx->dev, UINT_MAX);
  63
  64                 err = device_add(&ctx->dev);
  65                 if (err) {
  66                         dev_err(host1x->dev, "could not add context device %d: %d\n", i, err);
  67                         put_device(&ctx->dev);
  68                         goto unreg_devices;
  69                 }
  70
  71                 err = of_dma_configure_id(&ctx->dev, node, true, &i);
  72                 if (err) {
  73                         dev_err(host1x->dev, "IOMMU configuration failed for context device %d: %d\n",
  74                                 i, err);
  75                         device_unregister(&ctx->dev);
  76                         goto unreg_devices;
  77                 }
  78
  79                 if (!tegra_dev_iommu_get_stream_id(&ctx->dev, &ctx->stream_id) ||
  80                     !device_iommu_mapped(&ctx->dev)) {
  81                         dev_err(host1x->dev, "Context device %d has no IOMMU!\n", i);
  82                         device_unregister(&ctx->dev);
  83
  84                         /*
  85                          * This means that if IOMMU is disabled but context devices
  86                          * are defined in the device tree, Host1x will fail to probe.
  87                          * That's probably OK in this time and age.
  88                          */
  89                         err = -EINVAL;
  90
  91                         goto unreg_devices;
  92                 }
  93         }
  94
  95         return 0;
  96
  97 unreg_devices:
  98         while (i--)
  99                 device_unregister(&cdl->devs[i].dev);
 100
 101         kfree(cdl->devs);
 102         cdl->devs = NULL;
 103         cdl->len = 0;
 104
 105         return err;
 106 }
 107
 108 void host1x_memory_context_list_free(struct host1x_memory_context_list *cdl)
 109 {
 110         unsigned int i;
 111
 112         for (i = 0; i < cdl->len; i++)
 113                 device_unregister(&cdl->devs[i].dev);
 114
 115         kfree(cdl->devs);
 116         cdl->len = 0;
 117 }
 118
 119 struct host1x_memory_context *host1x_memory_context_alloc(struct host1x *host1x,
 120                                                           struct device *dev,
 121                                                           struct pid *pid)
 122 {
 123         struct host1x_memory_context_list *cdl = &host1x->context_list;
 124         struct host1x_memory_context *free = NULL;
 125         int i;
 126
 127         if (!cdl->len)
 128                 return ERR_PTR(-EOPNOTSUPP);
 129
 130         mutex_lock(&cdl->lock);
 131
 132         for (i = 0; i < cdl->len; i++) {
 133                 struct host1x_memory_context *cd = &cdl->devs[i];
 134
 135                 if (cd->dev.iommu->iommu_dev != dev->iommu->iommu_dev)
 136                         continue;
 137
 138                 if (cd->owner == pid) {
 139                         refcount_inc(&cd->ref);
 140                         mutex_unlock(&cdl->lock);
 141                         return cd;
 142                 } else if (!cd->owner && !free) {
 143                         free = cd;
 144                 }
 145         }
 146
 147         if (!free) {
 148                 mutex_unlock(&cdl->lock);
 149                 return ERR_PTR(-EBUSY);
 150         }
 151
 152         refcount_set(&free->ref, 1);
 153         free->owner = get_pid(pid);
 154
 155         mutex_unlock(&cdl->lock);
 156
 157         return free;
 158 }
 159 EXPORT_SYMBOL_GPL(host1x_memory_context_alloc);
 160
 161 void host1x_memory_context_get(struct host1x_memory_context *cd)
 162 {
 163         refcount_inc(&cd->ref);
 164 }
 165 EXPORT_SYMBOL_GPL(host1x_memory_context_get);
 166
 167 void host1x_memory_context_put(struct host1x_memory_context *cd)
 168 {
 169         struct host1x_memory_context_list *cdl = &cd->host->context_list;
 170
 171         if (refcount_dec_and_mutex_lock(&cd->ref, &cdl->lock)) {
 172                 put_pid(cd->owner);
 173                 cd->owner = NULL;
 174                 mutex_unlock(&cdl->lock);
 175         }
 176 }
 177 EXPORT_SYMBOL_GPL(host1x_memory_context_put);