dma-buf: heaps: Add heap helpers (5248eb12) · Commits · 戴 / test

drivers/dma-buf/Makefile

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		@@ -2,6 +2,7 @@
		obj-y := dma-buf.o dma-fence.o dma-fence-array.o dma-fence-chain.o \
		dma-resv.o seqno-fence.o
		obj-$(CONFIG_DMABUF_HEAPS) += dma-heap.o
		obj-$(CONFIG_DMABUF_HEAPS) += heaps/
		obj-$(CONFIG_SYNC_FILE) += sync_file.o
		obj-$(CONFIG_SW_SYNC) += sw_sync.o sync_debug.o
		obj-$(CONFIG_UDMABUF) += udmabuf.o

drivers/dma-buf/heaps/Makefile

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		# SPDX-License-Identifier: GPL-2.0
		obj-y += heap-helpers.o

drivers/dma-buf/heaps/heap-helpers.c

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		// SPDX-License-Identifier: GPL-2.0
		#include <linux/device.h>
		#include <linux/dma-buf.h>
		#include <linux/err.h>
		#include <linux/highmem.h>
		#include <linux/idr.h>
		#include <linux/list.h>
		#include <linux/slab.h>
		#include <linux/uaccess.h>
		#include <linux/vmalloc.h>
		#include <uapi/linux/dma-heap.h>

		#include "heap-helpers.h"

		void init_heap_helper_buffer(struct heap_helper_buffer *buffer,
		void (free)(struct heap_helper_buffer ))
		{
		buffer->priv_virt = NULL;
		mutex_init(&buffer->lock);
		buffer->vmap_cnt = 0;
		buffer->vaddr = NULL;
		buffer->pagecount = 0;
		buffer->pages = NULL;
		INIT_LIST_HEAD(&buffer->attachments);
		buffer->free = free;
		}

		struct dma_buf heap_helper_export_dmabuf(struct heap_helper_buffer buffer,
		int fd_flags)
		{
		DEFINE_DMA_BUF_EXPORT_INFO(exp_info);

		exp_info.ops = &heap_helper_ops;
		exp_info.size = buffer->size;
		exp_info.flags = fd_flags;
		exp_info.priv = buffer;

		return dma_buf_export(&exp_info);
		}

		static void dma_heap_map_kernel(struct heap_helper_buffer buffer)
		{
		void *vaddr;

		vaddr = vmap(buffer->pages, buffer->pagecount, VM_MAP, PAGE_KERNEL);
		if (!vaddr)
		return ERR_PTR(-ENOMEM);

		return vaddr;
		}

		static void dma_heap_buffer_destroy(struct heap_helper_buffer *buffer)
		{
		if (buffer->vmap_cnt > 0) {
		WARN(1, "%s: buffer still mapped in the kernel\n", __func__);
		vunmap(buffer->vaddr);
		}

		buffer->free(buffer);
		}

		static void dma_heap_buffer_vmap_get(struct heap_helper_buffer buffer)
		{
		void *vaddr;

		if (buffer->vmap_cnt) {
		buffer->vmap_cnt++;
		return buffer->vaddr;
		}
		vaddr = dma_heap_map_kernel(buffer);
		if (IS_ERR(vaddr))
		return vaddr;
		buffer->vaddr = vaddr;
		buffer->vmap_cnt++;
		return vaddr;
		}

		static void dma_heap_buffer_vmap_put(struct heap_helper_buffer *buffer)
		{
		if (!--buffer->vmap_cnt) {
		vunmap(buffer->vaddr);
		buffer->vaddr = NULL;
		}
		}

		struct dma_heaps_attachment {
		struct device *dev;
		struct sg_table table;
		struct list_head list;
		};

		static int dma_heap_attach(struct dma_buf *dmabuf,
		struct dma_buf_attachment *attachment)
		{
		struct dma_heaps_attachment *a;
		struct heap_helper_buffer *buffer = dmabuf->priv;
		int ret;

		a = kzalloc(sizeof(*a), GFP_KERNEL);
		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);

		attachment->priv = a;

		mutex_lock(&buffer->lock);
		list_add(&a->list, &buffer->attachments);
		mutex_unlock(&buffer->lock);

		return 0;
		}

		static void dma_heap_detach(struct dma_buf *dmabuf,
		struct dma_buf_attachment *attachment)
		{
		struct dma_heaps_attachment *a = attachment->priv;
		struct heap_helper_buffer *buffer = dmabuf->priv;

		mutex_lock(&buffer->lock);
		list_del(&a->list);
		mutex_unlock(&buffer->lock);

		sg_free_table(&a->table);
		kfree(a);
		}

		static
		struct sg_table dma_heap_map_dma_buf(struct dma_buf_attachment attachment,
		enum dma_data_direction direction)
		{
		struct dma_heaps_attachment *a = attachment->priv;
		struct sg_table *table;

		table = &a->table;

		if (!dma_map_sg(attachment->dev, table->sgl, table->nents,
		direction))
		table = ERR_PTR(-ENOMEM);
		return table;
		}

		static void dma_heap_unmap_dma_buf(struct dma_buf_attachment *attachment,
		struct sg_table *table,
		enum dma_data_direction direction)
		{
		dma_unmap_sg(attachment->dev, table->sgl, table->nents, direction);
		}

		static vm_fault_t dma_heap_vm_fault(struct vm_fault *vmf)
		{
		struct vm_area_struct *vma = vmf->vma;
		struct heap_helper_buffer *buffer = vma->vm_private_data;

		if (vmf->pgoff > buffer->pagecount)
		return VM_FAULT_SIGBUS;

		vmf->page = buffer->pages[vmf->pgoff];
		get_page(vmf->page);

		return 0;
		}

		static const struct vm_operations_struct dma_heap_vm_ops = {
		.fault = dma_heap_vm_fault,
		};

		static int dma_heap_mmap(struct dma_buf dmabuf, struct vm_area_struct vma)
		{
		struct heap_helper_buffer *buffer = dmabuf->priv;

		if ((vma->vm_flags & (VM_SHARED \| VM_MAYSHARE)) == 0)
		return -EINVAL;

		vma->vm_ops = &dma_heap_vm_ops;
		vma->vm_private_data = buffer;

		return 0;
		}

		static void dma_heap_dma_buf_release(struct dma_buf *dmabuf)
		{
		struct heap_helper_buffer *buffer = dmabuf->priv;

		dma_heap_buffer_destroy(buffer);
		}

		static int dma_heap_dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
		enum dma_data_direction direction)
		{
		struct heap_helper_buffer *buffer = dmabuf->priv;
		struct dma_heaps_attachment *a;
		int ret = 0;

		mutex_lock(&buffer->lock);

		if (buffer->vmap_cnt)
		invalidate_kernel_vmap_range(buffer->vaddr, buffer->size);

		list_for_each_entry(a, &buffer->attachments, list) {
		dma_sync_sg_for_cpu(a->dev, a->table.sgl, a->table.nents,
		direction);
		}
		mutex_unlock(&buffer->lock);

		return ret;
		}

		static int dma_heap_dma_buf_end_cpu_access(struct dma_buf *dmabuf,
		enum dma_data_direction direction)
		{
		struct heap_helper_buffer *buffer = dmabuf->priv;
		struct dma_heaps_attachment *a;

		mutex_lock(&buffer->lock);

		if (buffer->vmap_cnt)
		flush_kernel_vmap_range(buffer->vaddr, buffer->size);

		list_for_each_entry(a, &buffer->attachments, list) {
		dma_sync_sg_for_device(a->dev, a->table.sgl, a->table.nents,
		direction);
		}
		mutex_unlock(&buffer->lock);

		return 0;
		}

		static void dma_heap_dma_buf_vmap(struct dma_buf dmabuf)
		{
		struct heap_helper_buffer *buffer = dmabuf->priv;
		void *vaddr;

		mutex_lock(&buffer->lock);
		vaddr = dma_heap_buffer_vmap_get(buffer);
		mutex_unlock(&buffer->lock);

		return vaddr;
		}

		static void dma_heap_dma_buf_vunmap(struct dma_buf dmabuf, void vaddr)
		{
		struct heap_helper_buffer *buffer = dmabuf->priv;

		mutex_lock(&buffer->lock);
		dma_heap_buffer_vmap_put(buffer);
		mutex_unlock(&buffer->lock);
		}

		const struct dma_buf_ops heap_helper_ops = {
		.map_dma_buf = dma_heap_map_dma_buf,
		.unmap_dma_buf = dma_heap_unmap_dma_buf,
		.mmap = dma_heap_mmap,
		.release = dma_heap_dma_buf_release,
		.attach = dma_heap_attach,
		.detach = dma_heap_detach,
		.begin_cpu_access = dma_heap_dma_buf_begin_cpu_access,
		.end_cpu_access = dma_heap_dma_buf_end_cpu_access,
		.vmap = dma_heap_dma_buf_vmap,
		.vunmap = dma_heap_dma_buf_vunmap,
		};

drivers/dma-buf/heaps/heap-helpers.h

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		/* SPDX-License-Identifier: GPL-2.0 */
		/*
		* DMABUF Heaps helper code
		*
		* Copyright (C) 2011 Google, Inc.
		* Copyright (C) 2019 Linaro Ltd.
		*/

		#ifndef _HEAP_HELPERS_H
		#define _HEAP_HELPERS_H

		#include <linux/dma-heap.h>
		#include <linux/list.h>

		/**
		* struct heap_helper_buffer - helper buffer metadata
		* @heap: back pointer to the heap the buffer came from
		* @dmabuf: backing dma-buf for this buffer
		* @size: size of the buffer
		* @priv_virt pointer to heap specific private value
		* @lock mutext to protect the data in this structure
		* @vmap_cnt count of vmap references on the buffer
		* @vaddr vmap'ed virtual address
		* @pagecount number of pages in the buffer
		* @pages list of page pointers
		* @attachments list of device attachments
		*
		* @free heap callback to free the buffer
		*/
		struct heap_helper_buffer {
		struct dma_heap *heap;
		struct dma_buf *dmabuf;
		size_t size;

		void *priv_virt;
		struct mutex lock;
		int vmap_cnt;
		void *vaddr;
		pgoff_t pagecount;
		struct page **pages;
		struct list_head attachments;

		void (free)(struct heap_helper_buffer buffer);
		};

		void init_heap_helper_buffer(struct heap_helper_buffer *buffer,
		void (free)(struct heap_helper_buffer ));

		struct dma_buf heap_helper_export_dmabuf(struct heap_helper_buffer buffer,
		int fd_flags);

		extern const struct dma_buf_ops heap_helper_ops;
		#endif /* _HEAP_HELPERS_H */

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