Some reserved memory regions might have particular memory setup or attributes that make them good candidates for heaps.
Let's provide a heap type that will create a new heap for each reserved memory region flagged as such.
Signed-off-by: Maxime Ripard mripard@kernel.org --- drivers/dma-buf/heaps/Kconfig | 8 + drivers/dma-buf/heaps/Makefile | 1 + drivers/dma-buf/heaps/carveout_heap.c | 362 ++++++++++++++++++++++++++++++++++ 3 files changed, 371 insertions(+)
diff --git a/drivers/dma-buf/heaps/Kconfig b/drivers/dma-buf/heaps/Kconfig index a5eef06c422644e8aadaf5aff2bd9a33c49c1ba3..1ce4f6828d8c06bfdd7bc2e5127707f1778586e6 100644 --- a/drivers/dma-buf/heaps/Kconfig +++ b/drivers/dma-buf/heaps/Kconfig @@ -1,5 +1,13 @@ +config DMABUF_HEAPS_CARVEOUT + bool "DMA-BUF Carveout Heaps" + depends on DMABUF_HEAPS + help + Choose this option to enable the carveout dmabuf heap. The carveout + heap is backed by pages from reserved memory regions flagged as + exportable. If in doubt, say Y. + config DMABUF_HEAPS_SYSTEM bool "DMA-BUF System Heap" depends on DMABUF_HEAPS help Choose this option to enable the system dmabuf heap. The system heap diff --git a/drivers/dma-buf/heaps/Makefile b/drivers/dma-buf/heaps/Makefile index 974467791032ffb8a7aba17b1407d9a19b3f3b44..b734647ad5c84f449106748160258e372f153df2 100644 --- a/drivers/dma-buf/heaps/Makefile +++ b/drivers/dma-buf/heaps/Makefile @@ -1,3 +1,4 @@ # SPDX-License-Identifier: GPL-2.0 +obj-$(CONFIG_DMABUF_HEAPS_CARVEOUT) += carveout_heap.o obj-$(CONFIG_DMABUF_HEAPS_SYSTEM) += system_heap.o obj-$(CONFIG_DMABUF_HEAPS_CMA) += cma_heap.o diff --git a/drivers/dma-buf/heaps/carveout_heap.c b/drivers/dma-buf/heaps/carveout_heap.c new file mode 100644 index 0000000000000000000000000000000000000000..c01abc72c09d4f2a373462fded2856d975a36c8f --- /dev/null +++ b/drivers/dma-buf/heaps/carveout_heap.c @@ -0,0 +1,362 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <linux/dma-buf.h> +#include <linux/dma-heap.h> +#include <linux/genalloc.h> +#include <linux/highmem.h> +#include <linux/of_reserved_mem.h> + +struct carveout_heap_priv { + struct dma_heap *heap; + struct gen_pool *pool; +}; + +struct carveout_heap_buffer_priv { + struct mutex lock; + struct list_head attachments; + + unsigned long num_pages; + struct carveout_heap_priv *heap; + phys_addr_t paddr; + void *vaddr; + unsigned int vmap_cnt; +}; + +struct carveout_heap_attachment { + struct list_head head; + struct sg_table table; + + struct device *dev; + bool mapped; +}; + +static int carveout_heap_attach(struct dma_buf *buf, + struct dma_buf_attachment *attachment) +{ + struct carveout_heap_buffer_priv *priv = buf->priv; + struct carveout_heap_attachment *a; + struct sg_table *sgt; + unsigned long len = priv->num_pages * PAGE_SIZE; + int ret; + + a = kzalloc(sizeof(*a), GFP_KERNEL); + if (!a) + return -ENOMEM; + INIT_LIST_HEAD(&a->head); + a->dev = attachment->dev; + attachment->priv = a; + + sgt = &a->table; + ret = sg_alloc_table(sgt, 1, GFP_KERNEL); + if (ret) + goto err_cleanup_attach; + + sg_set_buf(sgt->sgl, priv->vaddr, len); + + mutex_lock(&priv->lock); + list_add(&a->head, &priv->attachments); + mutex_unlock(&priv->lock); + + return 0; + +err_cleanup_attach: + kfree(a); + return ret; +} + +static void carveout_heap_detach(struct dma_buf *dmabuf, + struct dma_buf_attachment *attachment) +{ + struct carveout_heap_buffer_priv *priv = dmabuf->priv; + struct carveout_heap_attachment *a = attachment->priv; + + mutex_lock(&priv->lock); + list_del(&a->head); + mutex_unlock(&priv->lock); + + sg_free_table(&a->table); + kfree(a); +} + +static struct sg_table * +carveout_heap_map_dma_buf(struct dma_buf_attachment *attachment, + enum dma_data_direction direction) +{ + struct carveout_heap_attachment *a = attachment->priv; + struct sg_table *table = &a->table; + int ret; + + ret = dma_map_sgtable(a->dev, table, direction, 0); + if (ret) + return ERR_PTR(ret); + + a->mapped = true; + + return table; +} + +static void carveout_heap_unmap_dma_buf(struct dma_buf_attachment *attachment, + struct sg_table *table, + enum dma_data_direction direction) +{ + struct carveout_heap_attachment *a = attachment->priv; + + a->mapped = false; + dma_unmap_sgtable(a->dev, table, direction, 0); +} + +static int +carveout_heap_dma_buf_begin_cpu_access(struct dma_buf *dmabuf, + enum dma_data_direction direction) +{ + struct carveout_heap_buffer_priv *priv = dmabuf->priv; + struct carveout_heap_attachment *a; + unsigned long len = priv->num_pages * PAGE_SIZE; + + mutex_lock(&priv->lock); + + if (priv->vmap_cnt) + invalidate_kernel_vmap_range(priv->vaddr, len); + + list_for_each_entry(a, &priv->attachments, head) { + if (!a->mapped) + continue; + + dma_sync_sgtable_for_cpu(a->dev, &a->table, direction); + } + + mutex_unlock(&priv->lock); + + return 0; +} + +static int +carveout_heap_dma_buf_end_cpu_access(struct dma_buf *dmabuf, + enum dma_data_direction direction) +{ + struct carveout_heap_buffer_priv *priv = dmabuf->priv; + struct carveout_heap_attachment *a; + unsigned long len = priv->num_pages * PAGE_SIZE; + + mutex_lock(&priv->lock); + + if (priv->vmap_cnt) + flush_kernel_vmap_range(priv->vaddr, len); + + list_for_each_entry(a, &priv->attachments, head) { + if (!a->mapped) + continue; + + dma_sync_sgtable_for_device(a->dev, &a->table, direction); + } + + mutex_unlock(&priv->lock); + + return 0; +} + +static int carveout_heap_mmap(struct dma_buf *dmabuf, + struct vm_area_struct *vma) +{ + struct carveout_heap_buffer_priv *priv = dmabuf->priv; + unsigned long len = priv->num_pages * PAGE_SIZE; + + return vm_iomap_memory(vma, priv->paddr, len); +} + +static int carveout_heap_vmap(struct dma_buf *dmabuf, struct iosys_map *map) +{ + struct carveout_heap_buffer_priv *priv = dmabuf->priv; + unsigned long len = priv->num_pages * PAGE_SIZE; + + mutex_lock(&priv->lock); + + if (!priv->vmap_cnt) { + void *vaddr = memremap(priv->paddr, len, MEMREMAP_WB); + + if (!vaddr) { + mutex_unlock(&priv->lock); + return -ENOMEM; + } + + priv->vaddr = vaddr; + } + + WARN_ON(!priv->vaddr); + iosys_map_set_vaddr(map, priv->vaddr); + priv->vmap_cnt++; + + mutex_unlock(&priv->lock); + + return 0; +} + +static void carveout_heap_vunmap(struct dma_buf *dmabuf, struct iosys_map *map) +{ + struct carveout_heap_buffer_priv *priv = dmabuf->priv; + + mutex_lock(&priv->lock); + + priv->vmap_cnt--; + if (!priv->vmap_cnt) { + memunmap(priv->vaddr); + priv->vaddr = NULL; + } + + mutex_unlock(&priv->lock); + + iosys_map_clear(map); +} + +static void carveout_heap_dma_buf_release(struct dma_buf *buf) +{ + struct carveout_heap_buffer_priv *buffer_priv = buf->priv; + struct carveout_heap_priv *heap_priv = buffer_priv->heap; + unsigned long len = buffer_priv->num_pages * PAGE_SIZE; + + gen_pool_free(heap_priv->pool, buffer_priv->paddr, len); + kfree(buffer_priv); +} + +static const struct dma_buf_ops carveout_heap_buf_ops = { + .attach = carveout_heap_attach, + .detach = carveout_heap_detach, + .map_dma_buf = carveout_heap_map_dma_buf, + .unmap_dma_buf = carveout_heap_unmap_dma_buf, + .begin_cpu_access = carveout_heap_dma_buf_begin_cpu_access, + .end_cpu_access = carveout_heap_dma_buf_end_cpu_access, + .mmap = carveout_heap_mmap, + .vmap = carveout_heap_vmap, + .vunmap = carveout_heap_vunmap, + .release = carveout_heap_dma_buf_release, +}; + +static struct dma_buf *carveout_heap_allocate(struct dma_heap *heap, + unsigned long len, + u32 fd_flags, + u64 heap_flags) +{ + struct carveout_heap_priv *heap_priv = dma_heap_get_drvdata(heap); + struct carveout_heap_buffer_priv *buffer_priv; + DEFINE_DMA_BUF_EXPORT_INFO(exp_info); + struct dma_buf *buf; + phys_addr_t paddr; + /* len is guaranteed to be page-aligned by the framework, so we can use it as is. */ + size_t size = len; + int ret; + + buffer_priv = kzalloc(sizeof(*buffer_priv), GFP_KERNEL); + if (!buffer_priv) + return ERR_PTR(-ENOMEM); + + INIT_LIST_HEAD(&buffer_priv->attachments); + mutex_init(&buffer_priv->lock); + + paddr = gen_pool_alloc(heap_priv->pool, size); + if (!paddr) { + ret = -ENOMEM; + goto err_free_buffer_priv; + } + + buffer_priv->paddr = paddr; + buffer_priv->heap = heap_priv; + buffer_priv->num_pages = size >> PAGE_SHIFT; + + /* create the dmabuf */ + exp_info.exp_name = dma_heap_get_name(heap); + exp_info.ops = &carveout_heap_buf_ops; + exp_info.size = size; + exp_info.flags = fd_flags; + exp_info.priv = buffer_priv; + + buf = dma_buf_export(&exp_info); + if (IS_ERR(buf)) { + ret = PTR_ERR(buf); + goto err_free_buffer; + } + + return buf; + +err_free_buffer: + gen_pool_free(heap_priv->pool, paddr, len); +err_free_buffer_priv: + kfree(buffer_priv); + + return ERR_PTR(ret); +} + +static const struct dma_heap_ops carveout_heap_ops = { + .allocate = carveout_heap_allocate, +}; + +static int __init carveout_heap_setup(struct device_node *node) +{ + struct dma_heap_export_info exp_info = {}; + const struct reserved_mem *rmem; + struct carveout_heap_priv *priv; + struct dma_heap *heap; + struct gen_pool *pool; + int ret; + + rmem = of_reserved_mem_lookup(node); + if (!rmem) + return -EINVAL; + + priv = kzalloc(sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + pool = gen_pool_create(PAGE_SHIFT, NUMA_NO_NODE); + if (!pool) { + ret = -ENOMEM; + goto err_cleanup_heap; + } + priv->pool = pool; + + ret = gen_pool_add(pool, rmem->base, rmem->size, NUMA_NO_NODE); + if (ret) + goto err_release_mem_region; + + exp_info.name = node->full_name; + exp_info.ops = &carveout_heap_ops; + exp_info.priv = priv; + + heap = dma_heap_add(&exp_info); + if (IS_ERR(heap)) { + ret = PTR_ERR(heap); + goto err_release_mem_region; + } + priv->heap = heap; + + return 0; + +err_release_mem_region: + gen_pool_destroy(pool); +err_cleanup_heap: + kfree(priv); + return ret; +} + +static int __init carveout_heap_init(void) +{ + struct device_node *rmem_node; + struct device_node *node; + int ret; + + rmem_node = of_find_node_by_path("/reserved-memory"); + if (!rmem_node) + return 0; + + for_each_child_of_node(rmem_node, node) { + if (!of_device_is_compatible(node, "carved-out")) + continue; + + ret = carveout_heap_setup(node); + if (ret) + return ret; + } + + return 0; +} + +module_init(carveout_heap_init);