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Commit bc8b1cbe authored by Patrick Daly's avatar Patrick Daly
Browse files

iommu: dma-mapping-fast: Avoid pci memory regions 



Certain memory regions are reserved by pci devices. When an endpoint
makes an access to these regions, the access is routed to the appropriate
location with the pci complex, and does not pass through the iommu into
the greater system. Therefore these address cannot be used for dma.

Change-Id: I1e909e4c0fbcadd53576b27a57cc49ed131cf328
Signed-off-by: default avatarPatrick Daly <pdaly@codeaurora.org>
parent 88d321d1

drivers/iommu/dma-mapping-fast.c

+47 −0
Original line number Diff line number Diff line
@@ -765,6 +765,51 @@ static struct dma_fast_smmu_mapping *__fast_smmu_create_mapping_sized( 
	return ERR_PTR(-ENOMEM);

}



/*

 * Based off of similar code from dma-iommu.c, but modified to use a different

 * iova allocator

 */

static void fast_smmu_reserve_pci_windows(struct device *dev,

			    struct dma_fast_smmu_mapping *mapping)

{

	struct pci_host_bridge *bridge;

	struct resource_entry *window;

	phys_addr_t start, end;

	struct pci_dev *pci_dev;

	unsigned long flags;



	if (!dev_is_pci(dev))

		return;



	pci_dev = to_pci_dev(dev);

	bridge = pci_find_host_bridge(pci_dev->bus);



	spin_lock_irqsave(&mapping->lock, flags);

	resource_list_for_each_entry(window, &bridge->windows) {

		if (resource_type(window->res) != IORESOURCE_MEM &&

		    resource_type(window->res) != IORESOURCE_IO)

			continue;



		start = round_down(window->res->start - window->offset,

				FAST_PAGE_SIZE);

		end = round_up(window->res->end - window->offset,

				FAST_PAGE_SIZE);

		start = max_t(unsigned long, mapping->base, start);

		end = min_t(unsigned long, mapping->base + mapping->size, end);

		if (start >= end)

			continue;



		dev_dbg(dev, "iova allocator reserved 0x%pa-0x%pa\n",

				&start, &end);



		start = (start - mapping->base) >> FAST_PAGE_SHIFT;

		end = (end - mapping->base) >> FAST_PAGE_SHIFT;

		bitmap_set(mapping->bitmap, start, end - start);

	}

	spin_unlock_irqrestore(&mapping->lock, flags);

}





/**

 * fast_smmu_attach_device

 * @dev: valid struct device pointer
@@ -798,6 +843,8 @@ int fast_smmu_attach_device(struct device *dev, 
	mapping->fast->domain = domain;

	mapping->fast->dev = dev;



	fast_smmu_reserve_pci_windows(dev, mapping->fast);



	group = dev->iommu_group;

	if (!group) {

		dev_err(dev, "No iommu associated with device\n");