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); 178