Hi Maxime, Thank you for the patch.
On lun., avril 07, 2025 at 18:29, Maxime Ripard <mrip...@kernel.org> wrote: > 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 <mrip...@kernel.org> > --- > drivers/dma-buf/heaps/Kconfig | 8 + > drivers/dma-buf/heaps/Makefile | 1 + > drivers/dma-buf/heaps/carveout_heap.c | 360 > ++++++++++++++++++++++++++++++++++ > 3 files changed, 369 insertions(+) > > diff --git a/drivers/dma-buf/heaps/Kconfig b/drivers/dma-buf/heaps/Kconfig > index > a5eef06c422644e8aadaf5aff2bd9a33c49c1ba3..c6981d696733b4d8d0c3f6f5a37d967fd6a1a4a2 > 100644 > --- a/drivers/dma-buf/heaps/Kconfig > +++ b/drivers/dma-buf/heaps/Kconfig > @@ -1,5 +1,13 @@ > +config DMABUF_HEAPS_CARVEOUT > + bool "Carveout Heaps" Nitpick: Shouldn't this be: "DMA-BUF Carveout Heaps" ? This way, we are consistent with the other entries in this Kconfig. In my opinion, I don't know enough about dma-buf to do a good review, but I've tried my best by comparing this to a downstream heap I'm using from: https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/drivers/dma-buf/heaps/carveout-heap.c?h=ti-android-linux-6.6.y Reviewed-by: Mattijs Korpershoek <mkorpersh...@kernel.org> > + 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..f7198b781ea57f4f60e554d917c9277e9a716b16 > --- /dev/null > +++ b/drivers/dma-buf/heaps/carveout_heap.c > @@ -0,0 +1,360 @@ > +// 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; > + dma_addr_t daddr; > + 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_dma_address(sgt->sgl) = priv->daddr; > + sg_dma_len(sgt->sgl) = 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(-ENOMEM); > + > + 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 > 0) > + 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 > 0) > + 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; > + struct page *page = virt_to_page(priv->vaddr); > + > + return remap_pfn_range(vma, vma->vm_start, page_to_pfn(page), > + len, vma->vm_page_prot); > +} > + > +static int carveout_heap_vmap(struct dma_buf *dmabuf, struct iosys_map *map) > +{ > + struct carveout_heap_buffer_priv *priv = dmabuf->priv; > + > + mutex_lock(&priv->lock); > + > + 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--; > + 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, (unsigned long)buffer_priv->vaddr, 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; > + dma_addr_t daddr; > + size_t size = PAGE_ALIGN(len); > + void *vaddr; > + 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); > + > + vaddr = gen_pool_dma_zalloc(heap_priv->pool, size, &daddr); > + if (!vaddr) { > + ret = -ENOMEM; > + goto err_free_buffer_priv; > + } > + > + buffer_priv->vaddr = vaddr; > + buffer_priv->daddr = daddr; > + 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, (unsigned long)vaddr, 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; > + void *base; > + 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; > + > + base = memremap(rmem->base, rmem->size, MEMREMAP_WB); > + if (!base) { > + ret = -ENOMEM; > + goto err_release_mem_region; > + } > + > + ret = gen_pool_add_virt(pool, (unsigned long)base, rmem->base, > + rmem->size, NUMA_NO_NODE); > + if (ret) > + goto err_unmap; > + > + 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_cleanup_pool_region; > + } > + priv->heap = heap; > + > + return 0; > + > +err_cleanup_pool_region: > + gen_pool_free(pool, (unsigned long)base, rmem->size); > +err_unmap: > + memunmap(base); > +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_property_read_bool(node, "export")) > + continue; > + > + ret = carveout_heap_setup(node); > + if (ret) > + return ret; > + } > + > + return 0; > +} > + > +module_init(carveout_heap_init); > > -- > 2.49.0
