Commit 8617a5c5 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Michael Ellerman
Browse files

powerpc/dma: handle iommu bypass in dma_iommu_ops 



Add a new iommu_bypass flag to struct dev_archdata so that the dma_iommu
implementation can handle the direct mapping transparently instead of
switiching ops around.  Setting of this flag is controlled by new
pci_controller_ops method.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Tested-by: default avatarChristian Zigotzky <chzigotzky@xenosoft.de>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent a20f507f

arch/powerpc/include/asm/device.h

+5 −0
Original line number Diff line number Diff line
@@ -19,6 +19,11 @@ struct iommu_table; 
 * drivers/macintosh/macio_asic.c

 */

struct dev_archdata {

	/*

	 * Set to %true if the dma_iommu_ops are requested to use a direct

	 * window instead of dynamically mapping memory.

	 */

	bool			iommu_bypass : 1;

	/*

	 * These two used to be a union. However, with the hybrid ops we need

	 * both so here we store both a DMA offset for direct mappings and

arch/powerpc/include/asm/dma-mapping.h

+8 −0
Original line number Diff line number Diff line
@@ -29,6 +29,14 @@ extern int dma_nommu_mmap_coherent(struct device *dev, 
				    struct vm_area_struct *vma,

				    void *cpu_addr, dma_addr_t handle,

				    size_t size, unsigned long attrs);

int dma_nommu_map_sg(struct device *dev, struct scatterlist *sgl,

		int nents, enum dma_data_direction direction,

		unsigned long attrs);

dma_addr_t dma_nommu_map_page(struct device *dev, struct page *page,

		unsigned long offset, size_t size,

		enum dma_data_direction dir, unsigned long attrs);

int dma_nommu_dma_supported(struct device *dev, u64 mask);

u64 dma_nommu_get_required_mask(struct device *dev);



#ifdef CONFIG_NOT_COHERENT_CACHE

/*

arch/powerpc/include/asm/pci-bridge.h

+2 −0
Original line number Diff line number Diff line
@@ -19,6 +19,8 @@ struct device_node; 
struct pci_controller_ops {

	void		(*dma_dev_setup)(struct pci_dev *pdev);

	void		(*dma_bus_setup)(struct pci_bus *bus);

	bool		(*iommu_bypass_supported)(struct pci_dev *pdev,

				u64 mask);



	int		(*probe_mode)(struct pci_bus *bus);

arch/powerpc/kernel/dma-iommu.c

+64 −6
Original line number Diff line number Diff line
@@ -6,12 +6,30 @@ 
 * busses using the iommu infrastructure

 */



#include <linux/dma-direct.h>

#include <linux/pci.h>

#include <asm/iommu.h>



/*

 * Generic iommu implementation

 */



/*

 * The coherent mask may be smaller than the real mask, check if we can

 * really use a direct window.

 */

static inline bool dma_iommu_alloc_bypass(struct device *dev)

{

	return dev->archdata.iommu_bypass &&

		dma_nommu_dma_supported(dev, dev->coherent_dma_mask);

}



static inline bool dma_iommu_map_bypass(struct device *dev,

		unsigned long attrs)

{

	return dev->archdata.iommu_bypass;

}



/* Allocates a contiguous real buffer and creates mappings over it.

 * Returns the virtual address of the buffer and sets dma_handle

 * to the dma address (mapping) of the first page.
@@ -20,6 +38,9 @@ static void *dma_iommu_alloc_coherent(struct device *dev, size_t size, 
				      dma_addr_t *dma_handle, gfp_t flag,

				      unsigned long attrs)

{

	if (dma_iommu_alloc_bypass(dev))

		return __dma_nommu_alloc_coherent(dev, size, dma_handle, flag,

				attrs);

	return iommu_alloc_coherent(dev, get_iommu_table_base(dev), size,

				    dma_handle, dev->coherent_dma_mask, flag,

				    dev_to_node(dev));
@@ -29,7 +50,11 @@ static void dma_iommu_free_coherent(struct device *dev, size_t size, 
				    void *vaddr, dma_addr_t dma_handle,

				    unsigned long attrs)

{

	iommu_free_coherent(get_iommu_table_base(dev), size, vaddr, dma_handle);

	if (dma_iommu_alloc_bypass(dev))

		__dma_nommu_free_coherent(dev, size, vaddr, dma_handle, attrs);

	else

		iommu_free_coherent(get_iommu_table_base(dev), size, vaddr,

				dma_handle);

}



/* Creates TCEs for a user provided buffer.  The user buffer must be
@@ -42,6 +67,9 @@ static dma_addr_t dma_iommu_map_page(struct device *dev, struct page *page, 
				     enum dma_data_direction direction,

				     unsigned long attrs)

{

	if (dma_iommu_map_bypass(dev, attrs))

		return dma_nommu_map_page(dev, page, offset, size, direction,

				attrs);

	return iommu_map_page(dev, get_iommu_table_base(dev), page, offset,

			      size, device_to_mask(dev), direction, attrs);

}
@@ -51,8 +79,9 @@ static void dma_iommu_unmap_page(struct device *dev, dma_addr_t dma_handle, 
				 size_t size, enum dma_data_direction direction,

				 unsigned long attrs)

{

	iommu_unmap_page(get_iommu_table_base(dev), dma_handle, size, direction,

			 attrs);

	if (!dma_iommu_map_bypass(dev, attrs))

		iommu_unmap_page(get_iommu_table_base(dev), dma_handle, size,

				direction,  attrs);

}
@@ -60,6 +89,8 @@ static int dma_iommu_map_sg(struct device *dev, struct scatterlist *sglist, 
			    int nelems, enum dma_data_direction direction,

			    unsigned long attrs)

{

	if (dma_iommu_map_bypass(dev, attrs))

		return dma_nommu_map_sg(dev, sglist, nelems, direction, attrs);

	return ppc_iommu_map_sg(dev, get_iommu_table_base(dev), sglist, nelems,

				device_to_mask(dev), direction, attrs);

}
@@ -68,10 +99,20 @@ static void dma_iommu_unmap_sg(struct device *dev, struct scatterlist *sglist, 
		int nelems, enum dma_data_direction direction,

		unsigned long attrs)

{

	if (!dma_iommu_map_bypass(dev, attrs))

		ppc_iommu_unmap_sg(get_iommu_table_base(dev), sglist, nelems,

			   direction, attrs);

}



static bool dma_iommu_bypass_supported(struct device *dev, u64 mask)

{

	struct pci_dev *pdev = to_pci_dev(dev);

	struct pci_controller *phb = pci_bus_to_host(pdev->bus);



	return phb->controller_ops.iommu_bypass_supported &&

		phb->controller_ops.iommu_bypass_supported(pdev, mask);

}



/* We support DMA to/from any memory page via the iommu */

int dma_iommu_dma_supported(struct device *dev, u64 mask)

{
@@ -83,12 +124,21 @@ int dma_iommu_dma_supported(struct device *dev, u64 mask) 
		return 0;

	}



	if (dev_is_pci(dev) && dma_iommu_bypass_supported(dev, mask)) {

		dev->archdata.iommu_bypass = true;

		dev_dbg(dev, "iommu: 64-bit OK, using fixed ops\n");

		return 1;

	}



	if (tbl->it_offset > (mask >> tbl->it_page_shift)) {

		dev_info(dev, "Warning: IOMMU offset too big for device mask\n");

		dev_info(dev, "mask: 0x%08llx, table offset: 0x%08lx\n",

				mask, tbl->it_offset << tbl->it_page_shift);

		return 0;

	} else

	}



	dev_dbg(dev, "iommu: not 64-bit, using default ops\n");

	dev->archdata.iommu_bypass = false;

	return 1;

}
@@ -96,9 +146,17 @@ u64 dma_iommu_get_required_mask(struct device *dev) 
{

	struct iommu_table *tbl = get_iommu_table_base(dev);

	u64 mask;



	if (!tbl)

		return 0;



	if (dev_is_pci(dev)) {

		u64 bypass_mask = dma_nommu_get_required_mask(dev);



		if (dma_iommu_bypass_supported(dev, bypass_mask))

			return bypass_mask;

	}



	mask = 1ULL < (fls_long(tbl->it_offset + tbl->it_size) - 1);

	mask += mask - 1;

arch/powerpc/kernel/dma.c

+8 −11
Original line number Diff line number Diff line
@@ -40,7 +40,7 @@ static u64 __maybe_unused get_pfn_limit(struct device *dev) 
	return pfn;

}



static int dma_nommu_dma_supported(struct device *dev, u64 mask)

int dma_nommu_dma_supported(struct device *dev, u64 mask)

{

#ifdef CONFIG_PPC64

	u64 limit = get_dma_offset(dev) + (memblock_end_of_DRAM() - 1);
@@ -178,7 +178,7 @@ int dma_nommu_mmap_coherent(struct device *dev, struct vm_area_struct *vma, 
			       vma->vm_page_prot);

}



static int dma_nommu_map_sg(struct device *dev, struct scatterlist *sgl,

int dma_nommu_map_sg(struct device *dev, struct scatterlist *sgl,

		int nents, enum dma_data_direction direction,

		unsigned long attrs)

{
@@ -209,7 +209,7 @@ static void dma_nommu_unmap_sg(struct device *dev, struct scatterlist *sgl, 
		__dma_sync_page(sg_page(sg), sg->offset, sg->length, direction);

}



static u64 dma_nommu_get_required_mask(struct device *dev)

u64 dma_nommu_get_required_mask(struct device *dev)

{

	u64 end, mask;
@@ -221,12 +221,9 @@ static u64 dma_nommu_get_required_mask(struct device *dev) 
	return mask;

}



static inline dma_addr_t dma_nommu_map_page(struct device *dev,

					     struct page *page,

					     unsigned long offset,

					     size_t size,

					     enum dma_data_direction dir,

					     unsigned long attrs)

dma_addr_t dma_nommu_map_page(struct device *dev, struct page *page,

		unsigned long offset, size_t size,

		enum dma_data_direction dir, unsigned long attrs)

{

	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))

		__dma_sync_page(page, offset, size, dir);

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