C++ pgprot_writecombine函数代码示例

static int rockchip_gem_alloc_iommu(struct rockchip_gem_object *rk_obj,
				    bool alloc_kmap)
{
	int ret;

	ret = rockchip_gem_get_pages(rk_obj);
	if (ret < 0)
		return ret;

	ret = rockchip_gem_iommu_map(rk_obj);
	if (ret < 0)
		goto err_free;

	if (alloc_kmap) {
		rk_obj->kvaddr = vmap(rk_obj->pages, rk_obj->num_pages, VM_MAP,
				      pgprot_writecombine(PAGE_KERNEL));
		if (!rk_obj->kvaddr) {
			DRM_ERROR("failed to vmap() buffer\n");
			ret = -ENOMEM;
			goto err_unmap;
		}
	}

	return 0;

err_unmap:
	rockchip_gem_iommu_unmap(rk_obj);
err_free:
	rockchip_gem_put_pages(rk_obj);

	return ret;
}

static int mips_dma_mmap(struct device *dev, struct vm_area_struct *vma,
	void *cpu_addr, dma_addr_t dma_addr, size_t size,
	unsigned long attrs)
{
	unsigned long user_count = vma_pages(vma);
	unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
	unsigned long addr = (unsigned long)cpu_addr;
	unsigned long off = vma->vm_pgoff;
	unsigned long pfn;
	int ret = -ENXIO;

	if (!plat_device_is_coherent(dev))
		addr = CAC_ADDR(addr);

	pfn = page_to_pfn(virt_to_page((void *)addr));

	if (attrs & DMA_ATTR_WRITE_COMBINE)
		vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
	else
		vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

	if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
		return ret;

	if (off < count && user_count <= (count - off)) {
		ret = remap_pfn_range(vma, vma->vm_start,
				      pfn + off,
				      user_count << PAGE_SHIFT,
				      vma->vm_page_prot);
	}

	return ret;
}

/*
 * Allocate a writecombining region, in much the same way as
 * dma_alloc_coherent above.
 */
void *
dma_alloc_writecombine(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp)
{
	return __dma_alloc(dev, size, handle, gfp,
			   pgprot_writecombine(pgprot_kernel),
			   __builtin_return_address(0));
}

pgprot_t arch_dma_mmap_pgprot(struct device *dev, pgprot_t prot,
		unsigned long attrs)
{
	if (!dev_is_dma_coherent(dev) || (attrs & DMA_ATTR_WRITE_COMBINE))
		return pgprot_writecombine(prot);
	return prot;
}

/*
	enable user space access to iram buffer
*/
static int imx_iram_audio_playback_mmap(struct snd_pcm_substream *substream,
					struct vm_area_struct *area)
{
	struct snd_dma_buffer *buf = &substream->dma_buffer;
	unsigned long off;
	unsigned long phys;
	unsigned long size;
	int ret = 0;

	area->vm_ops = &snd_mxc_audio_playback_vm_ops;
	area->vm_private_data = substream;

	off = area->vm_pgoff << PAGE_SHIFT;
	phys = buf->addr + off;
	size = area->vm_end - area->vm_start;

	if (off + size > SND_RAM_SIZE)
		return -EINVAL;

	area->vm_page_prot = pgprot_writecombine(area->vm_page_prot);
	area->vm_flags |= VM_IO;
	ret =
	    remap_pfn_range(area, area->vm_start, phys >> PAGE_SHIFT,
			    size, area->vm_page_prot);
	if (ret == 0)
		area->vm_ops->open(area);

	return ret;
}

/**
 * drm_gem_mmap_obj - memory map a GEM object
 * @obj: the GEM object to map
 * @obj_size: the object size to be mapped, in bytes
 * @vma: VMA for the area to be mapped
 *
 * Set up the VMA to prepare mapping of the GEM object using the gem_vm_ops
 * provided by the driver. Depending on their requirements, drivers can either
 * provide a fault handler in their gem_vm_ops (in which case any accesses to
 * the object will be trapped, to perform migration, GTT binding, surface
 * register allocation, or performance monitoring), or mmap the buffer memory
 * synchronously after calling drm_gem_mmap_obj.
 *
 * This function is mainly intended to implement the DMABUF mmap operation, when
 * the GEM object is not looked up based on its fake offset. To implement the
 * DRM mmap operation, drivers should use the drm_gem_mmap() function.
 *
 * drm_gem_mmap_obj() assumes the user is granted access to the buffer while
 * drm_gem_mmap() prevents unprivileged users from mapping random objects. So
 * callers must verify access restrictions before calling this helper.
 *
 * NOTE: This function has to be protected with dev->struct_mutex
 *
 * Return 0 or success or -EINVAL if the object size is smaller than the VMA
 * size, or if no gem_vm_ops are provided.
 */
int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size,
		     struct vm_area_struct *vma)
{
	struct drm_device *dev = obj->dev;

	lockdep_assert_held(&dev->struct_mutex);

	/* Check for valid size. */
	if (obj_size < vma->vm_end - vma->vm_start)
		return -EINVAL;

	if (!dev->driver->gem_vm_ops)
		return -EINVAL;

	vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
	vma->vm_ops = dev->driver->gem_vm_ops;
	vma->vm_private_data = obj;
	vma->vm_page_prot =  pgprot_writecombine(vm_get_page_prot(vma->vm_flags));

	/* Take a ref for this mapping of the object, so that the fault
	 * handler can dereference the mmap offset's pointer to the object.
	 * This reference is cleaned up by the corresponding vm_close
	 * (which should happen whether the vma was created by this call, or
	 * by a vm_open due to mremap or partial unmap or whatever).
	 */
	drm_gem_object_reference(obj);

	drm_vm_open_locked(dev, vma);
	return 0;
}

static pgprot_t __get_dma_pgprot(struct dma_attrs *attrs, pgprot_t prot,
				 bool coherent)
{
	if (!coherent || dma_get_attr(DMA_ATTR_WRITE_COMBINE, attrs))
		return pgprot_writecombine(prot);
	return prot;
}

int exynos_mem_mmap(struct file *filp, struct vm_area_struct *vma)
{
	struct exynos_mem *mem = (struct exynos_mem *)filp->private_data;
	bool cacheable = mem->cacheable;
	dma_addr_t start = vma->vm_pgoff << PAGE_SHIFT;
	u32 pfn = vma->vm_pgoff;
	u32 size = vma->vm_end - vma->vm_start;

	if (!cma_is_registered_region(start, size)) {
		pr_err("[%s] handling non-cma region (%#[email protected]%#x)is prohibited\n",
						__func__, size, start);
		return -EINVAL;
	}

	if (!cacheable)
		vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);

	vma->vm_flags |= VM_RESERVED;
	vma->vm_ops = &exynos_mem_ops;

	if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED)) {
		pr_err("writable mapping must be shared\n");
		return -EINVAL;
	}

	if (remap_pfn_range(vma, vma->vm_start, pfn, size, vma->vm_page_prot)) {
		pr_err("mmap fail\n");
		return -EINVAL;
	}

	vma->vm_ops->open(vma);

	return 0;
}

int ion_cp_heap_map_user(struct ion_heap *heap, struct ion_buffer *buffer,
			struct vm_area_struct *vma, unsigned long flags)
{
	int ret_value = -EAGAIN;
	struct ion_cp_heap *cp_heap =
		container_of(heap, struct ion_cp_heap, heap);

	mutex_lock(&cp_heap->lock);
	if (cp_heap->heap_protected == HEAP_NOT_PROTECTED) {
		if (ion_cp_request_region(cp_heap)) {
			mutex_unlock(&cp_heap->lock);
			return -EINVAL;
		}

		if (!ION_IS_CACHED(flags))
			vma->vm_page_prot = pgprot_writecombine(
							vma->vm_page_prot);

		ret_value =  remap_pfn_range(vma, vma->vm_start,
			__phys_to_pfn(buffer->priv_phys) + vma->vm_pgoff,
			vma->vm_end - vma->vm_start,
			vma->vm_page_prot);

		if (ret_value)
			ion_cp_release_region(cp_heap);
		else
			++cp_heap->umap_count;
	}
	mutex_unlock(&cp_heap->lock);
	return ret_value;
}

int
pci_mmap_page_range (struct pci_dev *dev, struct vm_area_struct *vma,
		     enum pci_mmap_state mmap_state, int write_combine)
{
	/*
	 * I/O space cannot be accessed via normal processor loads and
	 * stores on this platform.
	 */
	if (mmap_state == pci_mmap_io)
		/*
		 * XXX we could relax this for I/O spaces for which ACPI
		 * indicates that the space is 1-to-1 mapped.  But at the
		 * moment, we don't support multiple PCI address spaces and
		 * the legacy I/O space is not 1-to-1 mapped, so this is moot.
		 */
		return -EINVAL;

	/*
	 * Leave vm_pgoff as-is, the PCI space address is the physical
	 * address on this platform.
	 */
	if (write_combine && efi_range_is_wc(vma->vm_start,
					     vma->vm_end - vma->vm_start))
		vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
	else
		vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

	if (remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
			     vma->vm_end - vma->vm_start, vma->vm_page_prot))
		return -EAGAIN;

	return 0;
}

/** @note munmap handler is done by vma close handler */
int mali_mmap(struct file *filp, struct vm_area_struct *vma)
{
	struct mali_session_data *session;
	mali_mem_allocation *descriptor;
	u32 size = vma->vm_end - vma->vm_start;
	u32 mali_addr = vma->vm_pgoff << PAGE_SHIFT;

	session = (struct mali_session_data *)filp->private_data;
	if (NULL == session) {
		MALI_PRINT_ERROR(("mmap called without any session data available\n"));
		return -EFAULT;
	}

	MALI_DEBUG_PRINT(4, ("MMap() handler: start=0x%08X, phys=0x%08X, size=0x%08X vma->flags 0x%08x\n",
			     (unsigned int)vma->vm_start, (unsigned int)(vma->vm_pgoff << PAGE_SHIFT),
			     (unsigned int)(vma->vm_end - vma->vm_start), vma->vm_flags));

	/* Set some bits which indicate that, the memory is IO memory, meaning
	 * that no paging is to be performed and the memory should not be
	 * included in crash dumps. And that the memory is reserved, meaning
	 * that it's present and can never be paged out (see also previous
	 * entry)
	 */
	vma->vm_flags |= VM_IO;
	vma->vm_flags |= VM_DONTCOPY;
	vma->vm_flags |= VM_PFNMAP;
#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 7, 0)
	vma->vm_flags |= VM_RESERVED;
#else
	vma->vm_flags |= VM_DONTDUMP;
	vma->vm_flags |= VM_DONTEXPAND;
#endif

	vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
	vma->vm_ops = &mali_kernel_vm_ops; /* Operations used on any memory system */

	descriptor = mali_mem_block_alloc(mali_addr, size, vma, session);
	if (NULL == descriptor) {
		descriptor = mali_mem_os_alloc(mali_addr, size, vma, session);
		if (NULL == descriptor) {
			MALI_DEBUG_PRINT(3, ("MMAP failed\n"));
			return -ENOMEM;
		}
	}

	MALI_DEBUG_ASSERT(MALI_MEM_ALLOCATION_VALID_MAGIC == descriptor->magic);

	vma->vm_private_data = (void *)descriptor;

	/* Put on descriptor map */
	if (_MALI_OSK_ERR_OK != mali_descriptor_mapping_allocate_mapping(session->descriptor_mapping, descriptor, &descriptor->id)) {
		_mali_osk_mutex_wait(session->memory_lock);
		mali_mem_os_release(descriptor);
		_mali_osk_mutex_signal(session->memory_lock);
		return -EFAULT;
	}

	return 0;
}

static int hv_cdev_mmap(struct file *filp, struct vm_area_struct *vma)
{
	hv_cdev_private *priv = filp->private_data;

	int res;

	/* vm_pgoff = the offset of the area in the file, in pages */
	/* shift by PAGE_SHIFT to get physical addr offset         */
	unsigned long off = vma->vm_pgoff << PAGE_SHIFT;

	/* off is decided by user's mmap() offset parm. If 0, off=0 */
	phys_addr_t physical = priv->phys_start + off;

	unsigned long vsize = vma->vm_end - vma->vm_start;
	unsigned long psize = priv->dev_size - off;

	PINFO("%s: enter\n", __func__);
	PINFO("off=%lu, physical=%p, vsize=%lu, psize=%lu\n",
			off, (void *)physical, vsize, psize);

	if (vsize > psize) {
		PERR("%s: requested vma size exceeds disk size\n", __func__);
		return -EINVAL;
	}

	vma->vm_ops = &hv_cdev_vm_ops;

	switch (hv_mmap_type) {
	case 0:
	default:
		break;
	case 1:
		pgprot_writecombine(vma->vm_page_prot);
		break;
	case 2:
		pgprot_noncached(vma->vm_page_prot);
		break;
	}

	vma->vm_flags |= VM_LOCKED;	/* locked from swap */

	PDEBUG("phys_start=%p, page_frame_num=%d\n",
		(void *)priv->phys_start, (int)priv->phys_start >> PAGE_SHIFT);

	/* Remap the phys addr of device into user space virtual mem */
	res = remap_pfn_range(vma,
			vma->vm_start,
			physical >> PAGE_SHIFT,	/* = pfn */
			vsize,
			vma->vm_page_prot);

	if (res) {
		PERR("%s: error from remap_pfn_range()/n", __func__);
		return -EAGAIN;
	} else
		PDEBUG("%s: Physical mem remapped to user VA\n", __func__);

	return 0;
}

int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
{
	struct drm_file *priv = filp->private_data;
	struct drm_device *dev = priv->minor->dev;
	struct drm_gem_mm *mm = dev->mm_private;
	struct drm_local_map *map = NULL;
	struct drm_gem_object *obj;
	struct drm_hash_item *hash;
	int ret = 0;

	if (drm_device_is_unplugged(dev))
		return -ENODEV;

	mutex_lock(&dev->struct_mutex);

	if (drm_ht_find_item(&mm->offset_hash, vma->vm_pgoff, &hash)) {
		mutex_unlock(&dev->struct_mutex);
		return drm_mmap(filp, vma);
	}

	map = drm_hash_entry(hash, struct drm_map_list, hash)->map;
	if (!map ||
	    ((map->flags & _DRM_RESTRICTED) && !capable(CAP_SYS_ADMIN))) {
		ret =  -EPERM;
		goto out_unlock;
	}

	/*                       */
	if (map->size < vma->vm_end - vma->vm_start) {
		ret = -EINVAL;
		goto out_unlock;
	}

	obj = map->handle;
	if (!obj->dev->driver->gem_vm_ops) {
		ret = -EINVAL;
		goto out_unlock;
	}

	vma->vm_flags |= VM_RESERVED | VM_IO | VM_PFNMAP | VM_DONTEXPAND;
	vma->vm_ops = obj->dev->driver->gem_vm_ops;
	vma->vm_private_data = map->handle;
	vma->vm_page_prot =  pgprot_writecombine(vm_get_page_prot(vma->vm_flags));

	/*                                                             
                                                                    
                                                              
                                                                     
                                                             
  */
	drm_gem_object_reference(obj);

	drm_vm_open_locked(vma);

out_unlock:
	mutex_unlock(&dev->struct_mutex);

	return ret;
}

/**
 * drm_gem_mmap - memory map routine for GEM objects
 * @filp: DRM file pointer
 * @vma: VMA for the area to be mapped
 *
 * If a driver supports GEM object mapping, mmap calls on the DRM file
 * descriptor will end up here.
 *
 * If we find the object based on the offset passed in (vma->vm_pgoff will
 * contain the fake offset we created when the GTT map ioctl was called on
 * the object), we set up the driver fault handler so that any accesses
 * to the object can be trapped, to perform migration, GTT binding, surface
 * register allocation, or performance monitoring.
 */
int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
{
	struct drm_file *priv = filp->private_data;
	struct drm_device *dev = priv->minor->dev;
	struct drm_gem_mm *mm = dev->mm_private;
	struct drm_local_map *map = NULL;
	struct drm_gem_object *obj;
	struct drm_hash_item *hash;
	int ret = 0;

	if (drm_device_is_unplugged(dev))
		return -ENODEV;

	mutex_lock(&dev->struct_mutex);

	if (drm_ht_find_item(&mm->offset_hash, vma->vm_pgoff, &hash)) {
		mutex_unlock(&dev->struct_mutex);
		return drm_mmap(filp, vma);
	}

	map = drm_hash_entry(hash, struct drm_map_list, hash)->map;
	if (!map ||
	    ((map->flags & _DRM_RESTRICTED) && !capable(CAP_SYS_ADMIN))) {
		ret =  -EPERM;
		goto out_unlock;
	}

	/* Check for valid size. */
	if (map->size < vma->vm_end - vma->vm_start) {
		ret = -EINVAL;
		goto out_unlock;
	}

	obj = map->handle;
	if (!obj->dev->driver->gem_vm_ops) {
		ret = -EINVAL;
		goto out_unlock;
	}

	vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
	vma->vm_ops = obj->dev->driver->gem_vm_ops;
	vma->vm_private_data = map->handle;
	vma->vm_page_prot =  pgprot_writecombine(vm_get_page_prot(vma->vm_flags));

	/* Take a ref for this mapping of the object, so that the fault
	 * handler can dereference the mmap offset's pointer to the object.
	 * This reference is cleaned up by the corresponding vm_close
	 * (which should happen whether the vma was created by this call, or
	 * by a vm_open due to mremap or partial unmap or whatever).
	 */
	drm_gem_object_reference(obj);

	drm_vm_open_locked(dev, vma);

out_unlock:
	mutex_unlock(&dev->struct_mutex);

	return ret;
}

static int kbase_cpu_mmap(struct kbase_va_region *reg, struct vm_area_struct *vma, void *kaddr, u32 nr_pages)
{
	struct kbase_cpu_mapping *map;
	u64 start_off = vma->vm_pgoff - reg->start_pfn;
	phys_addr_t *page_array;
	int err = 0;
	int i;

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

	if (!map) {
		WARN_ON(1);
		err = -ENOMEM;
		goto out;
	}

	/*
	 * VM_DONTCOPY - don't make this mapping available in fork'ed processes
	 * VM_DONTEXPAND - disable mremap on this region
	 * VM_IO - disables paging
	 * VM_DONTDUMP - Don't include in core dumps (3.7 only)
	 * VM_MIXEDMAP - Support mixing struct page*s and raw pfns.
	 *               This is needed to support using the dedicated and
	 *               the OS based memory backends together.
	 */
	/*
	 * This will need updating to propagate coherency flags
	 * See MIDBASE-1057
	 */

#if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,7,0))
	vma->vm_flags |= VM_DONTCOPY | VM_DONTDUMP | VM_DONTEXPAND | VM_IO | VM_MIXEDMAP;
#else
	vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_RESERVED | VM_IO | VM_MIXEDMAP;
#endif
	vma->vm_ops = &kbase_vm_ops;
	vma->vm_private_data = reg;

	page_array = kbase_get_phy_pages(reg);

	if (!(reg->flags & KBASE_REG_CPU_CACHED)) {
		/* We can't map vmalloc'd memory uncached.
		 * Other memory will have been returned from
		 * kbase_phy_pages_alloc which should have done the cache
		 * maintenance necessary to support an uncached mapping
		 */
		BUG_ON(kaddr);
		vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
	}

	if (!kaddr) {
		for (i = 0; i < nr_pages; i++) {
			err = vm_insert_mixed(vma, vma->vm_start + (i << PAGE_SHIFT), page_array[i + start_off] >> PAGE_SHIFT);
			WARN_ON(err);
			if (err)
				break;
		}
	} else {