From: John Stultz john.stultz@linaro.org

Keep track of the heap device struct.

This will be useful for special DMA allocations and actions.

Signed-off-by: John Stultz john.stultz@linaro.org Signed-off-by: Albert Esteve aesteve@redhat.com --- drivers/dma-buf/dma-heap.c | 34 ++++++++++++++++++++++++++-------- include/linux/dma-heap.h | 2 ++ 2 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/drivers/dma-buf/dma-heap.c b/drivers/dma-buf/dma-heap.c index ac5f8685a6494..1124d63eb1398 100644 --- a/drivers/dma-buf/dma-heap.c +++ b/drivers/dma-buf/dma-heap.c @@ -31,6 +31,7 @@ * @heap_devt: heap device node * @list: list head connecting to list of heaps * @heap_cdev: heap char device + * @heap_dev: heap device * * Represents a heap of memory from which buffers can be made. */ @@ -41,6 +42,7 @@ struct dma_heap { dev_t heap_devt; struct list_head list; struct cdev heap_cdev; + struct device *heap_dev; };

static LIST_HEAD(heap_list); @@ -223,6 +225,19 @@ const char *dma_heap_get_name(struct dma_heap *heap) } EXPORT_SYMBOL_NS_GPL(dma_heap_get_name, "DMA_BUF_HEAP");

+/** + * dma_heap_get_dev() - get device struct for the heap + * @heap: DMA-Heap to retrieve device struct from + * + * Returns: + * The device struct for the heap. + */ +struct device *dma_heap_get_dev(struct dma_heap *heap) +{ + return heap->heap_dev; +} +EXPORT_SYMBOL_NS_GPL(dma_heap_get_dev, "DMA_BUF_HEAP"); + /** * dma_heap_add - adds a heap to dmabuf heaps * @exp_info: information needed to register this heap @@ -230,7 +245,6 @@ EXPORT_SYMBOL_NS_GPL(dma_heap_get_name, "DMA_BUF_HEAP"); struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info) { struct dma_heap *heap, *h, *err_ret; - struct device *dev_ret; unsigned int minor; int ret;

@@ -272,14 +286,14 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info) goto err1; }

- dev_ret = device_create(dma_heap_class, - NULL, - heap->heap_devt, - NULL, - heap->name); - if (IS_ERR(dev_ret)) { + heap->heap_dev = device_create(dma_heap_class, + NULL, + heap->heap_devt, + NULL, + heap->name); + if (IS_ERR(heap->heap_dev)) { pr_err("dma_heap: Unable to create device\n"); - err_ret = ERR_CAST(dev_ret); + err_ret = ERR_CAST(heap->heap_dev); goto err2; }

@@ -295,6 +309,10 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info) } }

+ /* Make sure it doesn't disappear on us */ + heap->heap_dev = get_device(heap->heap_dev); + + /* Add heap to the list */ list_add(&heap->list, &heap_list); mutex_unlock(&heap_list_lock); diff --git a/include/linux/dma-heap.h b/include/linux/dma-heap.h index 648328a64b27e..493085e69b70e 100644 --- a/include/linux/dma-heap.h +++ b/include/linux/dma-heap.h @@ -12,6 +12,7 @@ #include <linux/types.h>

struct dma_heap; +struct device;

/** * struct dma_heap_ops - ops to operate on a given heap @@ -43,6 +44,7 @@ struct dma_heap_export_info { void *dma_heap_get_drvdata(struct dma_heap *heap);

const char *dma_heap_get_name(struct dma_heap *heap); +struct device *dma_heap_get_dev(struct dma_heap *heap);

struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info);

Split dma_heap_add() into creation and registration phases while preserving the ordering between cdev_add() and device_add(), and ensuring all device fields are initialised.

This will allow to access the heap_dev before it is registered and becomes available to userspace, making error handling easier.

Signed-off-by: Albert Esteve aesteve@redhat.com --- drivers/dma-buf/dma-heap.c | 126 +++++++++++++++++++++++++++++++++++---------- include/linux/dma-heap.h | 3 ++ 2 files changed, 103 insertions(+), 26 deletions(-)

diff --git a/drivers/dma-buf/dma-heap.c b/drivers/dma-buf/dma-heap.c index 1124d63eb1398..88189d4e48561 100644 --- a/drivers/dma-buf/dma-heap.c +++ b/drivers/dma-buf/dma-heap.c @@ -238,15 +238,30 @@ struct device *dma_heap_get_dev(struct dma_heap *heap) } EXPORT_SYMBOL_NS_GPL(dma_heap_get_dev, "DMA_BUF_HEAP");

+static void dma_heap_dev_release(struct device *dev) +{ + struct dma_heap *heap; + + pr_debug("heap device: '%s': %s\n", dev_name(dev), __func__); + heap = dev_get_drvdata(dev); + kfree(heap->name); + kfree(heap); + kfree(dev); +} + /** - * dma_heap_add - adds a heap to dmabuf heaps - * @exp_info: information needed to register this heap + * dma_heap_create() - allocate and initialize a heap object + * @exp_info: information needed to create a heap + * + * Creates a heap instance but does not register it or create device nodes. + * Use dma_heap_register() to make it visible to userspace, or + * dma_heap_destroy() to release it. + * + * Returns a heap on success or ERR_PTR(-errno) on failure. */ -struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info) +struct dma_heap *dma_heap_create(const struct dma_heap_export_info *exp_info) { - struct dma_heap *heap, *h, *err_ret; - unsigned int minor; - int ret; + struct dma_heap *heap;

if (!exp_info->name || !strcmp(exp_info->name, "")) { pr_err("dma_heap: Cannot add heap without a name\n"); @@ -265,13 +280,41 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info) heap->name = exp_info->name; heap->ops = exp_info->ops; heap->priv = exp_info->priv; + heap->heap_dev = kzalloc_obj(*heap->heap_dev); + if (!heap->heap_dev) { + kfree(heap); + return ERR_PTR(-ENOMEM); + } + + device_initialize(heap->heap_dev); + dev_set_drvdata(heap->heap_dev, heap); + + dev_set_name(heap->heap_dev, heap->name); + heap->heap_dev->class = dma_heap_class; + heap->heap_dev->release = dma_heap_dev_release; + + return heap; +} +EXPORT_SYMBOL_NS_GPL(dma_heap_create, "DMA_BUF_HEAP"); + +/** + * dma_heap_register() - register a heap with the dma-heap framework + * @heap: heap instance created with dma_heap_create() + * + * Registers the heap, creating its device node and adding it to the heap + * list. Returns 0 on success or a negative error code on failure. + */ +int dma_heap_register(struct dma_heap *heap) +{ + struct dma_heap *h; + unsigned int minor; + int ret;

/* Find unused minor number */ ret = xa_alloc(&dma_heap_minors, &minor, heap, XA_LIMIT(0, NUM_HEAP_MINORS - 1), GFP_KERNEL); if (ret < 0) { pr_err("dma_heap: Unable to get minor number for heap\n"); - err_ret = ERR_PTR(ret); goto err0; }

@@ -282,42 +325,34 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info) ret = cdev_add(&heap->heap_cdev, heap->heap_devt, 1); if (ret < 0) { pr_err("dma_heap: Unable to add char device\n"); - err_ret = ERR_PTR(ret); goto err1; }

- heap->heap_dev = device_create(dma_heap_class, - NULL, - heap->heap_devt, - NULL, - heap->name); - if (IS_ERR(heap->heap_dev)) { - pr_err("dma_heap: Unable to create device\n"); - err_ret = ERR_CAST(heap->heap_dev); + heap->heap_dev->devt = heap->heap_devt; + + ret = device_add(heap->heap_dev); + if (ret) { + pr_err("dma_heap: Unable to add device\n"); goto err2; }

mutex_lock(&heap_list_lock); /* check the name is unique */ list_for_each_entry(h, &heap_list, list) { - if (!strcmp(h->name, exp_info->name)) { + if (!strcmp(h->name, heap->name)) { mutex_unlock(&heap_list_lock); pr_err("dma_heap: Already registered heap named %s\n", - exp_info->name); - err_ret = ERR_PTR(-EINVAL); + heap->name); + ret = -EINVAL; goto err3; } }

- /* Make sure it doesn't disappear on us */ - heap->heap_dev = get_device(heap->heap_dev); - - /* Add heap to the list */ list_add(&heap->list, &heap_list); mutex_unlock(&heap_list_lock);

- return heap; + return 0;

err3: device_destroy(dma_heap_class, heap->heap_devt); @@ -326,8 +361,47 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info) err1: xa_erase(&dma_heap_minors, minor); err0: - kfree(heap); - return err_ret; + dma_heap_destroy(heap); + return ret; +} +EXPORT_SYMBOL_NS_GPL(dma_heap_register, "DMA_BUF_HEAP"); + +/** + * dma_heap_destroy() - release a heap created by dma_heap_create() + * @heap: heap instance to release + * + * Drops the heap device reference; the heap and its device are freed in the + * device release path when the last reference is gone. + */ +void dma_heap_destroy(struct dma_heap *heap) +{ + put_device(heap->heap_dev); +} +EXPORT_SYMBOL_NS_GPL(dma_heap_destroy, "DMA_BUF_HEAP"); + +/** + * dma_heap_add - adds a heap to dmabuf heaps + * @exp_info: information needed to register this heap + */ +struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info) +{ + struct dma_heap *heap; + int ret; + + heap = dma_heap_create(exp_info); + if (IS_ERR(heap)) { + pr_err("dma_heap: failed to create heap (%d)\n", PTR_ERR(heap)); + return PTR_ERR(heap); + } + + ret = dma_heap_register(heap); + if (ret) { + pr_err("dma_heap: failed to register heap (%d)\n", ret); + dma_heap_destroy(heap); + return ERR_PTR(ret); + } + + return heap; } EXPORT_SYMBOL_NS_GPL(dma_heap_add, "DMA_BUF_HEAP");

diff --git a/include/linux/dma-heap.h b/include/linux/dma-heap.h index 493085e69b70e..1b0ea43ba66c3 100644 --- a/include/linux/dma-heap.h +++ b/include/linux/dma-heap.h @@ -46,6 +46,9 @@ void *dma_heap_get_drvdata(struct dma_heap *heap); const char *dma_heap_get_name(struct dma_heap *heap); struct device *dma_heap_get_dev(struct dma_heap *heap);

+struct dma_heap *dma_heap_create(const struct dma_heap_export_info *exp_info); +int dma_heap_register(struct dma_heap *heap); +void dma_heap_destroy(struct dma_heap *heap); struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info);

extern bool mem_accounting;

Add a dma-buf heap for DT coherent reserved-memory (i.e., 'shared-dma-pool' without 'reusable' property), exposing one heap per region for userspace buffers.

The heap binds the heap device to each memory region so coherent allocations use the correct dev->dma_mem, and it defers registration until module_init when normal allocators are available.

Signed-off-by: Albert Esteve aesteve@redhat.com --- drivers/dma-buf/dma-heap.c | 4 +- drivers/dma-buf/heaps/Kconfig | 9 + drivers/dma-buf/heaps/Makefile | 1 + drivers/dma-buf/heaps/coherent_heap.c | 426 ++++++++++++++++++++++++++++++++++ include/linux/dma-heap.h | 11 + include/linux/dma-map-ops.h | 7 + 6 files changed, 456 insertions(+), 2 deletions(-)

diff --git a/drivers/dma-buf/dma-heap.c b/drivers/dma-buf/dma-heap.c index 88189d4e48561..ba87e5ac16ae2 100644 --- a/drivers/dma-buf/dma-heap.c +++ b/drivers/dma-buf/dma-heap.c @@ -390,8 +390,8 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info)

heap = dma_heap_create(exp_info); if (IS_ERR(heap)) { - pr_err("dma_heap: failed to create heap (%d)\n", PTR_ERR(heap)); - return PTR_ERR(heap); + pr_err("dma_heap: failed to create heap (%ld)\n", PTR_ERR(heap)); + return ERR_CAST(heap); }

ret = dma_heap_register(heap); diff --git a/drivers/dma-buf/heaps/Kconfig b/drivers/dma-buf/heaps/Kconfig index a5eef06c42264..aeb475e585048 100644 --- a/drivers/dma-buf/heaps/Kconfig +++ b/drivers/dma-buf/heaps/Kconfig @@ -12,3 +12,12 @@ config DMABUF_HEAPS_CMA Choose this option to enable dma-buf CMA heap. This heap is backed by the Contiguous Memory Allocator (CMA). If your system has these regions, you should say Y here. + +config DMABUF_HEAPS_COHERENT + bool "DMA-BUF Coherent Reserved-Memory Heap" + depends on DMABUF_HEAPS && OF_RESERVED_MEM && DMA_DECLARE_COHERENT + help + Choose this option to enable coherent reserved-memory dma-buf heaps. + This heap is backed by non-reusable DT "shared-dma-pool" regions. + If your system defines coherent reserved-memory regions, you should + say Y here. diff --git a/drivers/dma-buf/heaps/Makefile b/drivers/dma-buf/heaps/Makefile index 974467791032f..96bda7a65f041 100644 --- a/drivers/dma-buf/heaps/Makefile +++ b/drivers/dma-buf/heaps/Makefile @@ -1,3 +1,4 @@ # SPDX-License-Identifier: GPL-2.0 obj-$(CONFIG_DMABUF_HEAPS_SYSTEM) += system_heap.o obj-$(CONFIG_DMABUF_HEAPS_CMA) += cma_heap.o +obj-$(CONFIG_DMABUF_HEAPS_COHERENT) += coherent_heap.o diff --git a/drivers/dma-buf/heaps/coherent_heap.c b/drivers/dma-buf/heaps/coherent_heap.c new file mode 100644 index 0000000000000..d033d737bb9df --- /dev/null +++ b/drivers/dma-buf/heaps/coherent_heap.c @@ -0,0 +1,426 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * DMABUF heap for coherent reserved-memory regions + * + * Copyright (C) 2026 Red Hat, Inc. + * Author: Albert Esteve aesteve@redhat.com + * + */ + +#include <linux/dma-buf.h> +#include <linux/dma-heap.h> +#include <linux/dma-map-ops.h> +#include <linux/dma-mapping.h> +#include <linux/err.h> +#include <linux/highmem.h> +#include <linux/iosys-map.h> +#include <linux/of_reserved_mem.h> +#include <linux/scatterlist.h> +#include <linux/slab.h> +#include <linux/vmalloc.h> + +struct coherent_heap { + struct dma_heap *heap; + struct reserved_mem *rmem; + char *name; +}; + +struct coherent_heap_buffer { + struct coherent_heap *heap; + struct list_head attachments; + struct mutex lock; + unsigned long len; + dma_addr_t dma_addr; + void *alloc_vaddr; + struct page **pages; + pgoff_t pagecount; + int vmap_cnt; + void *vaddr; +}; + +struct dma_heap_attachment { + struct device *dev; + struct sg_table table; + struct list_head list; + bool mapped; +}; + +static int coherent_heap_attach(struct dma_buf *dmabuf, + struct dma_buf_attachment *attachment) +{ + struct coherent_heap_buffer *buffer = dmabuf->priv; + struct dma_heap_attachment *a; + int ret; + + a = kzalloc_obj(*a); + if (!a) + return -ENOMEM; + + ret = sg_alloc_table_from_pages(&a->table, buffer->pages, + buffer->pagecount, 0, + buffer->pagecount << PAGE_SHIFT, + GFP_KERNEL); + if (ret) { + kfree(a); + return ret; + } + + a->dev = attachment->dev; + INIT_LIST_HEAD(&a->list); + a->mapped = false; + + attachment->priv = a; + + mutex_lock(&buffer->lock); + list_add(&a->list, &buffer->attachments); + mutex_unlock(&buffer->lock); + + return 0; +} + +static void coherent_heap_detach(struct dma_buf *dmabuf, + struct dma_buf_attachment *attachment) +{ + struct coherent_heap_buffer *buffer = dmabuf->priv; + struct dma_heap_attachment *a = attachment->priv; + + mutex_lock(&buffer->lock); + list_del(&a->list); + mutex_unlock(&buffer->lock); + + sg_free_table(&a->table); + kfree(a); +} + +static struct sg_table *coherent_heap_map_dma_buf(struct dma_buf_attachment *attachment, + enum dma_data_direction direction) +{ + struct dma_heap_attachment *a = attachment->priv; + struct sg_table *table = &a->table; + int ret; + + ret = dma_map_sgtable(attachment->dev, table, direction, 0); + if (ret) + return ERR_PTR(-ENOMEM); + a->mapped = true; + + return table; +} + +static void coherent_heap_unmap_dma_buf(struct dma_buf_attachment *attachment, + struct sg_table *table, + enum dma_data_direction direction) +{ + struct dma_heap_attachment *a = attachment->priv; + + a->mapped = false; + dma_unmap_sgtable(attachment->dev, table, direction, 0); +} + +static int coherent_heap_dma_buf_begin_cpu_access(struct dma_buf *dmabuf, + enum dma_data_direction direction) +{ + struct coherent_heap_buffer *buffer = dmabuf->priv; + struct dma_heap_attachment *a; + + mutex_lock(&buffer->lock); + if (buffer->vmap_cnt) + invalidate_kernel_vmap_range(buffer->vaddr, buffer->len); + + list_for_each_entry(a, &buffer->attachments, list) { + if (!a->mapped) + continue; + dma_sync_sgtable_for_cpu(a->dev, &a->table, direction); + } + mutex_unlock(&buffer->lock); + + return 0; +} + +static int coherent_heap_dma_buf_end_cpu_access(struct dma_buf *dmabuf, + enum dma_data_direction direction) +{ + struct coherent_heap_buffer *buffer = dmabuf->priv; + struct dma_heap_attachment *a; + + mutex_lock(&buffer->lock); + if (buffer->vmap_cnt) + flush_kernel_vmap_range(buffer->vaddr, buffer->len); + + list_for_each_entry(a, &buffer->attachments, list) { + if (!a->mapped) + continue; + dma_sync_sgtable_for_device(a->dev, &a->table, direction); + } + mutex_unlock(&buffer->lock); + + return 0; +} + +static int coherent_heap_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma) +{ + struct coherent_heap_buffer *buffer = dmabuf->priv; + struct coherent_heap *coh_heap = buffer->heap; + struct device *heap_dev = dma_heap_get_dev(coh_heap->heap); + + return dma_mmap_coherent(heap_dev, vma, buffer->alloc_vaddr, + buffer->dma_addr, buffer->len); +} + +static void *coherent_heap_do_vmap(struct coherent_heap_buffer *buffer) +{ + void *vaddr; + + vaddr = vmap(buffer->pages, buffer->pagecount, VM_MAP, PAGE_KERNEL); + if (!vaddr) + return ERR_PTR(-ENOMEM); + + return vaddr; +} + +static int coherent_heap_vmap(struct dma_buf *dmabuf, struct iosys_map *map) +{ + struct coherent_heap_buffer *buffer = dmabuf->priv; + void *vaddr; + int ret = 0; + + mutex_lock(&buffer->lock); + if (buffer->vmap_cnt) { + buffer->vmap_cnt++; + iosys_map_set_vaddr(map, buffer->vaddr); + goto out; + } + + vaddr = coherent_heap_do_vmap(buffer); + if (IS_ERR(vaddr)) { + ret = PTR_ERR(vaddr); + goto out; + } + + buffer->vaddr = vaddr; + buffer->vmap_cnt++; + iosys_map_set_vaddr(map, buffer->vaddr); +out: + mutex_unlock(&buffer->lock); + + return ret; +} + +static void coherent_heap_vunmap(struct dma_buf *dmabuf, struct iosys_map *map) +{ + struct coherent_heap_buffer *buffer = dmabuf->priv; + + mutex_lock(&buffer->lock); + if (!--buffer->vmap_cnt) { + vunmap(buffer->vaddr); + buffer->vaddr = NULL; + } + mutex_unlock(&buffer->lock); + iosys_map_clear(map); +} + +static void coherent_heap_dma_buf_release(struct dma_buf *dmabuf) +{ + struct coherent_heap_buffer *buffer = dmabuf->priv; + struct coherent_heap *coh_heap = buffer->heap; + struct device *heap_dev = dma_heap_get_dev(coh_heap->heap); + + if (buffer->vmap_cnt > 0) { + WARN(1, "%s: buffer still mapped in the kernel\n", __func__); + vunmap(buffer->vaddr); + buffer->vaddr = NULL; + buffer->vmap_cnt = 0; + } + + if (buffer->alloc_vaddr) + dma_free_coherent(heap_dev, buffer->len, buffer->alloc_vaddr, + buffer->dma_addr); + kfree(buffer->pages); + kfree(buffer); +} + +static const struct dma_buf_ops coherent_heap_buf_ops = { + .attach = coherent_heap_attach, + .detach = coherent_heap_detach, + .map_dma_buf = coherent_heap_map_dma_buf, + .unmap_dma_buf = coherent_heap_unmap_dma_buf, + .begin_cpu_access = coherent_heap_dma_buf_begin_cpu_access, + .end_cpu_access = coherent_heap_dma_buf_end_cpu_access, + .mmap = coherent_heap_mmap, + .vmap = coherent_heap_vmap, + .vunmap = coherent_heap_vunmap, + .release = coherent_heap_dma_buf_release, +}; + +static struct dma_buf *coherent_heap_allocate(struct dma_heap *heap, + unsigned long len, + u32 fd_flags, + u64 heap_flags) +{ + struct coherent_heap *coh_heap; + struct coherent_heap_buffer *buffer; + struct device *heap_dev; + DEFINE_DMA_BUF_EXPORT_INFO(exp_info); + size_t size = PAGE_ALIGN(len); + pgoff_t pagecount = size >> PAGE_SHIFT; + struct dma_buf *dmabuf; + int ret = -ENOMEM; + pgoff_t pg; + + coh_heap = dma_heap_get_drvdata(heap); + if (!coh_heap) + return ERR_PTR(-EINVAL); + + heap_dev = dma_heap_get_dev(coh_heap->heap); + if (!heap_dev) + return ERR_PTR(-ENODEV); + + buffer = kzalloc_obj(*buffer); + if (!buffer) + return ERR_PTR(-ENOMEM); + + INIT_LIST_HEAD(&buffer->attachments); + mutex_init(&buffer->lock); + buffer->len = size; + buffer->heap = coh_heap; + buffer->pagecount = pagecount; + + buffer->alloc_vaddr = dma_alloc_coherent(heap_dev, buffer->len, + &buffer->dma_addr, GFP_KERNEL); + if (!buffer->alloc_vaddr) { + ret = -ENOMEM; + goto free_buffer; + } + + buffer->pages = kmalloc_array(pagecount, sizeof(*buffer->pages), + GFP_KERNEL); + if (!buffer->pages) { + ret = -ENOMEM; + goto free_dma; + } + + for (pg = 0; pg < pagecount; pg++) + buffer->pages[pg] = virt_to_page((char *)buffer->alloc_vaddr + + (pg * PAGE_SIZE)); + + /* create the dmabuf */ + exp_info.exp_name = dma_heap_get_name(heap); + exp_info.ops = &coherent_heap_buf_ops; + exp_info.size = buffer->len; + exp_info.flags = fd_flags; + exp_info.priv = buffer; + dmabuf = dma_buf_export(&exp_info); + if (IS_ERR(dmabuf)) { + ret = PTR_ERR(dmabuf); + goto free_pages; + } + return dmabuf; + +free_pages: + kfree(buffer->pages); +free_dma: + dma_free_coherent(heap_dev, buffer->len, buffer->alloc_vaddr, + buffer->dma_addr); +free_buffer: + kfree(buffer); + return ERR_PTR(ret); +} + +static const struct dma_heap_ops coherent_heap_ops = { + .allocate = coherent_heap_allocate, +}; + +static int coherent_heap_init_dma_mask(struct device *dev) +{ + int ret; + + ret = dma_coerce_mask_and_coherent(dev, DMA_BIT_MASK(64)); + if (!ret) + return 0; + + /* Fallback to 32-bit DMA mask */ + return dma_coerce_mask_and_coherent(dev, DMA_BIT_MASK(32)); +} + +static int __coherent_heap_register(struct reserved_mem *rmem) +{ + struct dma_heap_export_info exp_info; + struct coherent_heap *coh_heap; + struct device *heap_dev; + int ret; + + if (!rmem || !rmem->name) + return -EINVAL; + + coh_heap = kzalloc_obj(*coh_heap); + if (!coh_heap) + return -ENOMEM; + + coh_heap->rmem = rmem; + coh_heap->name = kstrdup(rmem->name, GFP_KERNEL); + if (!coh_heap->name) { + ret = -ENOMEM; + goto free_coherent_heap; + } + + exp_info.name = coh_heap->name; + exp_info.ops = &coherent_heap_ops; + exp_info.priv = coh_heap; + + coh_heap->heap = dma_heap_create(&exp_info); + if (IS_ERR(coh_heap->heap)) { + ret = PTR_ERR(coh_heap->heap); + goto free_name; + } + + heap_dev = dma_heap_get_dev(coh_heap->heap); + ret = coherent_heap_init_dma_mask(heap_dev); + if (ret) { + pr_err("coherent_heap: failed to set DMA mask (%d)\n", ret); + goto destroy_heap; + } + + ret = of_reserved_mem_device_init_with_mem(heap_dev, rmem); + if (ret) { + pr_err("coherent_heap: failed to initialize memory (%d)\n", ret); + goto destroy_heap; + } + + ret = dma_heap_register(coh_heap->heap); + if (ret) { + pr_err("coherent_heap: failed to register heap (%d)\n", ret); + goto destroy_heap; + } + + return 0; + +destroy_heap: + dma_heap_destroy(coh_heap->heap); + coh_heap->heap = NULL; +free_name: + kfree(coh_heap->name); +free_coherent_heap: + kfree(coh_heap); + + return ret; +} + +static int __init coherent_heap_register(void) +{ + struct reserved_mem *rmem; + unsigned int i; + int ret; + + for (i = 0; (rmem = dma_coherent_get_reserved_region(i)) != NULL; i++) { + ret = __coherent_heap_register(rmem); + if (ret) { + pr_warn("Failed to add coherent heap %s", + rmem->name ? rmem->name : "unknown"); + continue; + } + } + + return 0; +} +module_init(coherent_heap_register); +MODULE_DESCRIPTION("DMA-BUF heap for coherent reserved-memory regions"); diff --git a/include/linux/dma-heap.h b/include/linux/dma-heap.h index 1b0ea43ba66c3..77e6cb66ffce1 100644 --- a/include/linux/dma-heap.h +++ b/include/linux/dma-heap.h @@ -9,10 +9,12 @@ #ifndef _DMA_HEAPS_H #define _DMA_HEAPS_H

+#include <linux/errno.h> #include <linux/types.h>

struct dma_heap; struct device; +struct reserved_mem;

/** * struct dma_heap_ops - ops to operate on a given heap @@ -53,4 +55,13 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info);

extern bool mem_accounting;

+#if IS_ENABLED(CONFIG_DMABUF_HEAPS_COHERENT) +int dma_heap_coherent_register(struct reserved_mem *rmem); +#else +static inline int dma_heap_coherent_register(struct reserved_mem *rmem) +{ + return -EOPNOTSUPP; +} +#endif + #endif /* _DMA_HEAPS_H */ diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h index 60b63756df821..c87e5e44e5383 100644 --- a/include/linux/dma-map-ops.h +++ b/include/linux/dma-map-ops.h @@ -12,6 +12,7 @@

struct cma; struct iommu_ops; +struct reserved_mem;

struct dma_map_ops { void *(*alloc)(struct device *dev, size_t size, @@ -161,6 +162,7 @@ int dma_alloc_from_dev_coherent(struct device *dev, ssize_t size, int dma_release_from_dev_coherent(struct device *dev, int order, void *vaddr); int dma_mmap_from_dev_coherent(struct device *dev, struct vm_area_struct *vma, void *cpu_addr, size_t size, int *ret); +struct reserved_mem *dma_coherent_get_reserved_region(unsigned int idx); #else static inline int dma_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr, dma_addr_t device_addr, size_t size) @@ -172,6 +174,11 @@ static inline int dma_declare_coherent_memory(struct device *dev, #define dma_release_from_dev_coherent(dev, order, vaddr) (0) #define dma_mmap_from_dev_coherent(dev, vma, vaddr, order, ret) (0) static inline void dma_release_coherent_memory(struct device *dev) { } +static inline +struct reserved_mem *dma_coherent_get_reserved_region(unsigned int idx) +{ + return NULL; +} #endif /* CONFIG_DMA_DECLARE_COHERENT */

#ifdef CONFIG_DMA_GLOBAL_POOL

Following the current efforts to make CMA heap as module, we can do the same and turn the Coherent heap into a module as well, by changing the Kconfig into a tristate and importing the proper dma-buf namespaces.

This heap won't be able to unload (same as happens with the CMA heap), since we're missing a big part of the infrastructure that would allow to make it safe.

Signed-off-by: Albert Esteve aesteve@redhat.com --- drivers/dma-buf/heaps/Kconfig | 2 +- drivers/dma-buf/heaps/coherent_heap.c | 3 +++ 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/dma-buf/heaps/Kconfig b/drivers/dma-buf/heaps/Kconfig index aeb475e585048..2f84a1018b900 100644 --- a/drivers/dma-buf/heaps/Kconfig +++ b/drivers/dma-buf/heaps/Kconfig @@ -14,7 +14,7 @@ config DMABUF_HEAPS_CMA regions, you should say Y here.

config DMABUF_HEAPS_COHERENT - bool "DMA-BUF Coherent Reserved-Memory Heap" + tristate "DMA-BUF Coherent Reserved-Memory Heap" depends on DMABUF_HEAPS && OF_RESERVED_MEM && DMA_DECLARE_COHERENT help Choose this option to enable coherent reserved-memory dma-buf heaps. diff --git a/drivers/dma-buf/heaps/coherent_heap.c b/drivers/dma-buf/heaps/coherent_heap.c index d033d737bb9df..cdf8efa6c1564 100644 --- a/drivers/dma-buf/heaps/coherent_heap.c +++ b/drivers/dma-buf/heaps/coherent_heap.c @@ -424,3 +424,6 @@ static int __init coherent_heap_register(void) } module_init(coherent_heap_register); MODULE_DESCRIPTION("DMA-BUF heap for coherent reserved-memory regions"); +MODULE_LICENSE("GPL"); +MODULE_IMPORT_NS("DMA_BUF"); +MODULE_IMPORT_NS("DMA_BUF_HEAP");