arch/x86/kernel/pci-dma.c - maze/linux - Git at Google

 #include <linux/dma-mapping.h>
 #include <linux/dma-debug.h>
 #include <linux/dmar.h>
 #include <linux/bootmem.h>
 #include <linux/pci.h>

 #include <asm/proto.h>
 #include <asm/dma.h>
 #include <asm/iommu.h>
 #include <asm/gart.h>
 #include <asm/calgary.h>
 #include <asm/amd_iommu.h>

 static int forbid_dac __read_mostly;

 struct dma_map_ops *dma_ops;
 EXPORT_SYMBOL(dma_ops);

 static int iommu_sac_force __read_mostly;

 #ifdef CONFIG_IOMMU_DEBUG
 int panic_on_overflow __read_mostly = 1;
 int force_iommu __read_mostly = 1;
 #else
 int panic_on_overflow __read_mostly = 0;
 int force_iommu __read_mostly = 0;
 #endif

 int iommu_merge __read_mostly = 0;

 int no_iommu __read_mostly;
 /* Set this to 1 if there is a HW IOMMU in the system */
 int iommu_detected __read_mostly = 0;

 dma_addr_t bad_dma_address __read_mostly = 0;
 EXPORT_SYMBOL(bad_dma_address);

 /* Dummy device used for NULL arguments (normally ISA). Better would
    be probably a smaller DMA mask, but this is bug-to-bug compatible
    to older i386. */
 struct device x86_dma_fallback_dev = {
 	.init_name = "fallback device",
 	.coherent_dma_mask = DMA_BIT_MASK(32),
 	.dma_mask = &x86_dma_fallback_dev.coherent_dma_mask,
 };
 EXPORT_SYMBOL(x86_dma_fallback_dev);

 /* Number of entries preallocated for DMA-API debugging */
 #define PREALLOC_DMA_DEBUG_ENTRIES       32768

 int dma_set_mask(struct device *dev, u64 mask)
 {
 	if (!dev->dma_mask || !dma_supported(dev, mask))
 		return -EIO;

 	*dev->dma_mask = mask;

 	return 0;
 }
 EXPORT_SYMBOL(dma_set_mask);

 #ifdef CONFIG_X86_64
 static __initdata void *dma32_bootmem_ptr;
 static unsigned long dma32_bootmem_size __initdata = (128ULL<<20);

 static int __init parse_dma32_size_opt(char *p)
 {
 	if (!p)
 		return -EINVAL;
 	dma32_bootmem_size = memparse(p, &p);
 	return 0;
 }
 early_param("dma32_size", parse_dma32_size_opt);

 void __init dma32_reserve_bootmem(void)
 {
 	unsigned long size, align;
 	if (max_pfn <= MAX_DMA32_PFN)
 		return;

 	/*
 	 * check aperture_64.c allocate_aperture() for reason about
 	 * using 512M as goal
 	 */
 	align = 64ULL<<20;
 	size = roundup(dma32_bootmem_size, align);
 	dma32_bootmem_ptr = __alloc_bootmem_nopanic(size, align,
 				 512ULL<<20);
 	if (dma32_bootmem_ptr)
 		dma32_bootmem_size = size;
 	else
 		dma32_bootmem_size = 0;
 }
 static void __init dma32_free_bootmem(void)
 {

 	if (max_pfn <= MAX_DMA32_PFN)
 		return;

 	if (!dma32_bootmem_ptr)
 		return;

 	free_bootmem(__pa(dma32_bootmem_ptr), dma32_bootmem_size);

 	dma32_bootmem_ptr = NULL;
 	dma32_bootmem_size = 0;
 }
 #endif

 void __init pci_iommu_alloc(void)
 {
 #ifdef CONFIG_X86_64
 	/* free the range so iommu could get some range less than 4G */
 	dma32_free_bootmem();
 #endif

 	/*
 	 * The order of these functions is important for
 	 * fall-back/fail-over reasons
 	 */
 	gart_iommu_hole_init();

 	detect_calgary();

 	detect_intel_iommu();

 	amd_iommu_detect();

 	pci_swiotlb_init();
 }

 void *dma_generic_alloc_coherent(struct device *dev, size_t size,
 				 dma_addr_t *dma_addr, gfp_t flag)
 {
 	unsigned long dma_mask;
 	struct page *page;
 	dma_addr_t addr;

 	dma_mask = dma_alloc_coherent_mask(dev, flag);

 	flag |= __GFP_ZERO;
 again:
 	page = alloc_pages_node(dev_to_node(dev), flag, get_order(size));
 	if (!page)
 		return NULL;

 	addr = page_to_phys(page);
 	if (!is_buffer_dma_capable(dma_mask, addr, size)) {
 		__free_pages(page, get_order(size));

 		if (dma_mask < DMA_BIT_MASK(32) && !(flag & GFP_DMA)) {
 			flag = (flag & ~GFP_DMA32) | GFP_DMA;
 			goto again;
 		}

 		return NULL;
 	}

 	*dma_addr = addr;
 	return page_address(page);
 }

 /*
  * See <Documentation/x86_64/boot-options.txt> for the iommu kernel parameter
  * documentation.
  */
 static __init int iommu_setup(char *p)
 {
 	iommu_merge = 1;

 	if (!p)
 		return -EINVAL;

 	while (*p) {
 		if (!strncmp(p, "off", 3))
 			no_iommu = 1;
 		/* gart_parse_options has more force support */
 		if (!strncmp(p, "force", 5))
 			force_iommu = 1;
 		if (!strncmp(p, "noforce", 7)) {
 			iommu_merge = 0;
 			force_iommu = 0;
 		}

 		if (!strncmp(p, "biomerge", 8)) {
 			iommu_merge = 1;
 			force_iommu = 1;
 		}
 		if (!strncmp(p, "panic", 5))
 			panic_on_overflow = 1;
 		if (!strncmp(p, "nopanic", 7))
 			panic_on_overflow = 0;
 		if (!strncmp(p, "merge", 5)) {
 			iommu_merge = 1;
 			force_iommu = 1;
 		}
 		if (!strncmp(p, "nomerge", 7))
 			iommu_merge = 0;
 		if (!strncmp(p, "forcesac", 8))
 			iommu_sac_force = 1;
 		if (!strncmp(p, "allowdac", 8))
 			forbid_dac = 0;
 		if (!strncmp(p, "nodac", 5))
 			forbid_dac = -1;
 		if (!strncmp(p, "usedac", 6)) {
 			forbid_dac = -1;
 			return 1;
 		}
 #ifdef CONFIG_SWIOTLB
 		if (!strncmp(p, "soft", 4))
 			swiotlb = 1;
 #endif

 		gart_parse_options(p);

 #ifdef CONFIG_CALGARY_IOMMU
 		if (!strncmp(p, "calgary", 7))
 			use_calgary = 1;
 #endif /* CONFIG_CALGARY_IOMMU */

 		p += strcspn(p, ",");
 		if (*p == ',')
 			++p;
 	}
 	return 0;
 }
 early_param("iommu", iommu_setup);

 int dma_supported(struct device *dev, u64 mask)
 {
 	struct dma_map_ops *ops = get_dma_ops(dev);

 #ifdef CONFIG_PCI
 	if (mask > 0xffffffff && forbid_dac > 0) {
 		dev_info(dev, "PCI: Disallowing DAC for device\n");
 		return 0;
 	}
 #endif

 	if (ops->dma_supported)
 		return ops->dma_supported(dev, mask);

 	/* Copied from i386. Doesn't make much sense, because it will
 	   only work for pci_alloc_coherent.
 	   The caller just has to use GFP_DMA in this case. */
 	if (mask < DMA_BIT_MASK(24))
 		return 0;

 	/* Tell the device to use SAC when IOMMU force is on.  This
 	   allows the driver to use cheaper accesses in some cases.

 	   Problem with this is that if we overflow the IOMMU area and
 	   return DAC as fallback address the device may not handle it
 	   correctly.

 	   As a special case some controllers have a 39bit address
 	   mode that is as efficient as 32bit (aic79xx). Don't force
 	   SAC for these.  Assume all masks <= 40 bits are of this
 	   type. Normally this doesn't make any difference, but gives
 	   more gentle handling of IOMMU overflow. */
 	if (iommu_sac_force && (mask >= DMA_BIT_MASK(40))) {
 		dev_info(dev, "Force SAC with mask %Lx\n", mask);
 		return 0;
 	}

 	return 1;
 }
 EXPORT_SYMBOL(dma_supported);

 static int __init pci_iommu_init(void)
 {
 	dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);

 #ifdef CONFIG_PCI
 	dma_debug_add_bus(&pci_bus_type);
 #endif

 	calgary_iommu_init();

 	intel_iommu_init();

 	amd_iommu_init();

 	gart_iommu_init();

 	no_iommu_init();
 	return 0;
 }

 void pci_iommu_shutdown(void)
 {
 	gart_iommu_shutdown();
 }
 /* Must execute after PCI subsystem */
 fs_initcall(pci_iommu_init);

 #ifdef CONFIG_PCI
 /* Many VIA bridges seem to corrupt data for DAC. Disable it here */

 static __devinit void via_no_dac(struct pci_dev *dev)
 {
 	if ((dev->class >> 8) == PCI_CLASS_BRIDGE_PCI && forbid_dac == 0) {
 		dev_info(&dev->dev, "disabling DAC on VIA PCI bridge\n");
 		forbid_dac = 1;
 	}
 }
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_VIA, PCI_ANY_ID, via_no_dac);
 #endif
	#include <linux/dma-mapping.h>
	#include <linux/dma-debug.h>
	#include <linux/dmar.h>
	#include <linux/bootmem.h>
	#include <linux/pci.h>

	#include <asm/proto.h>
	#include <asm/dma.h>
	#include <asm/iommu.h>
	#include <asm/gart.h>
	#include <asm/calgary.h>
	#include <asm/amd_iommu.h>

	static int forbid_dac __read_mostly;

	struct dma_map_ops *dma_ops;
	EXPORT_SYMBOL(dma_ops);

	static int iommu_sac_force __read_mostly;

	#ifdef CONFIG_IOMMU_DEBUG
	int panic_on_overflow __read_mostly = 1;
	int force_iommu __read_mostly = 1;
	#else
	int panic_on_overflow __read_mostly = 0;
	int force_iommu __read_mostly = 0;
	#endif

	int iommu_merge __read_mostly = 0;

	int no_iommu __read_mostly;
	/* Set this to 1 if there is a HW IOMMU in the system */
	int iommu_detected __read_mostly = 0;

	dma_addr_t bad_dma_address __read_mostly = 0;
	EXPORT_SYMBOL(bad_dma_address);

	/* Dummy device used for NULL arguments (normally ISA). Better would
	be probably a smaller DMA mask, but this is bug-to-bug compatible
	to older i386. */
	struct device x86_dma_fallback_dev = {
	.init_name = "fallback device",
	.coherent_dma_mask = DMA_BIT_MASK(32),
	.dma_mask = &x86_dma_fallback_dev.coherent_dma_mask,
	};
	EXPORT_SYMBOL(x86_dma_fallback_dev);

	/* Number of entries preallocated for DMA-API debugging */
	#define PREALLOC_DMA_DEBUG_ENTRIES 32768

	int dma_set_mask(struct device *dev, u64 mask)
	{
	if (!dev->dma_mask \|\| !dma_supported(dev, mask))
	return -EIO;

	*dev->dma_mask = mask;

	return 0;
	}
	EXPORT_SYMBOL(dma_set_mask);

	#ifdef CONFIG_X86_64
	static __initdata void *dma32_bootmem_ptr;
	static unsigned long dma32_bootmem_size __initdata = (128ULL<<20);

	static int __init parse_dma32_size_opt(char *p)
	{
	if (!p)
	return -EINVAL;
	dma32_bootmem_size = memparse(p, &p);
	return 0;
	}
	early_param("dma32_size", parse_dma32_size_opt);

	void __init dma32_reserve_bootmem(void)
	{
	unsigned long size, align;
	if (max_pfn <= MAX_DMA32_PFN)
	return;

	/*
	* check aperture_64.c allocate_aperture() for reason about
	* using 512M as goal
	*/
	align = 64ULL<<20;
	size = roundup(dma32_bootmem_size, align);
	dma32_bootmem_ptr = __alloc_bootmem_nopanic(size, align,
	512ULL<<20);
	if (dma32_bootmem_ptr)
	dma32_bootmem_size = size;
	else
	dma32_bootmem_size = 0;
	}
	static void __init dma32_free_bootmem(void)
	{

	if (max_pfn <= MAX_DMA32_PFN)
	return;

	if (!dma32_bootmem_ptr)
	return;

	free_bootmem(__pa(dma32_bootmem_ptr), dma32_bootmem_size);

	dma32_bootmem_ptr = NULL;
	dma32_bootmem_size = 0;
	}
	#endif

	void __init pci_iommu_alloc(void)
	{
	#ifdef CONFIG_X86_64
	/* free the range so iommu could get some range less than 4G */
	dma32_free_bootmem();
	#endif

	/*
	* The order of these functions is important for
	* fall-back/fail-over reasons
	*/
	gart_iommu_hole_init();

	detect_calgary();

	detect_intel_iommu();

	amd_iommu_detect();

	pci_swiotlb_init();
	}

	void dma_generic_alloc_coherent(struct device dev, size_t size,
	dma_addr_t *dma_addr, gfp_t flag)
	{
	unsigned long dma_mask;
	struct page *page;
	dma_addr_t addr;

	dma_mask = dma_alloc_coherent_mask(dev, flag);

	flag \|= __GFP_ZERO;
	again:
	page = alloc_pages_node(dev_to_node(dev), flag, get_order(size));
	if (!page)
	return NULL;

	addr = page_to_phys(page);
	if (!is_buffer_dma_capable(dma_mask, addr, size)) {
	__free_pages(page, get_order(size));

	if (dma_mask < DMA_BIT_MASK(32) && !(flag & GFP_DMA)) {
	flag = (flag & ~GFP_DMA32) \| GFP_DMA;
	goto again;
	}

	return NULL;
	}

	*dma_addr = addr;
	return page_address(page);
	}

	/*
	* See <Documentation/x86_64/boot-options.txt> for the iommu kernel parameter
	* documentation.
	*/
	static __init int iommu_setup(char *p)
	{
	iommu_merge = 1;

	if (!p)
	return -EINVAL;

	while (*p) {
	if (!strncmp(p, "off", 3))
	no_iommu = 1;
	/* gart_parse_options has more force support */
	if (!strncmp(p, "force", 5))
	force_iommu = 1;
	if (!strncmp(p, "noforce", 7)) {
	iommu_merge = 0;
	force_iommu = 0;
	}

	if (!strncmp(p, "biomerge", 8)) {
	iommu_merge = 1;
	force_iommu = 1;
	}
	if (!strncmp(p, "panic", 5))
	panic_on_overflow = 1;
	if (!strncmp(p, "nopanic", 7))
	panic_on_overflow = 0;
	if (!strncmp(p, "merge", 5)) {
	iommu_merge = 1;
	force_iommu = 1;
	}
	if (!strncmp(p, "nomerge", 7))
	iommu_merge = 0;
	if (!strncmp(p, "forcesac", 8))
	iommu_sac_force = 1;
	if (!strncmp(p, "allowdac", 8))
	forbid_dac = 0;
	if (!strncmp(p, "nodac", 5))
	forbid_dac = -1;
	if (!strncmp(p, "usedac", 6)) {
	forbid_dac = -1;
	return 1;
	}
	#ifdef CONFIG_SWIOTLB
	if (!strncmp(p, "soft", 4))
	swiotlb = 1;
	#endif

	gart_parse_options(p);

	#ifdef CONFIG_CALGARY_IOMMU
	if (!strncmp(p, "calgary", 7))
	use_calgary = 1;
	#endif /* CONFIG_CALGARY_IOMMU */

	p += strcspn(p, ",");
	if (*p == ',')
	++p;
	}
	return 0;
	}
	early_param("iommu", iommu_setup);

	int dma_supported(struct device *dev, u64 mask)
	{
	struct dma_map_ops *ops = get_dma_ops(dev);

	#ifdef CONFIG_PCI
	if (mask > 0xffffffff && forbid_dac > 0) {
	dev_info(dev, "PCI: Disallowing DAC for device\n");
	return 0;
	}
	#endif

	if (ops->dma_supported)
	return ops->dma_supported(dev, mask);

	/* Copied from i386. Doesn't make much sense, because it will
	only work for pci_alloc_coherent.
	The caller just has to use GFP_DMA in this case. */
	if (mask < DMA_BIT_MASK(24))
	return 0;

	/* Tell the device to use SAC when IOMMU force is on. This
	allows the driver to use cheaper accesses in some cases.

	Problem with this is that if we overflow the IOMMU area and
	return DAC as fallback address the device may not handle it
	correctly.

	As a special case some controllers have a 39bit address
	mode that is as efficient as 32bit (aic79xx). Don't force
	SAC for these. Assume all masks <= 40 bits are of this
	type. Normally this doesn't make any difference, but gives
	more gentle handling of IOMMU overflow. */
	if (iommu_sac_force && (mask >= DMA_BIT_MASK(40))) {
	dev_info(dev, "Force SAC with mask %Lx\n", mask);
	return 0;
	}

	return 1;
	}
	EXPORT_SYMBOL(dma_supported);

	static int __init pci_iommu_init(void)
	{
	dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);

	#ifdef CONFIG_PCI
	dma_debug_add_bus(&pci_bus_type);
	#endif

	calgary_iommu_init();

	intel_iommu_init();

	amd_iommu_init();

	gart_iommu_init();

	no_iommu_init();
	return 0;
	}

	void pci_iommu_shutdown(void)
	{
	gart_iommu_shutdown();
	}
	/* Must execute after PCI subsystem */
	fs_initcall(pci_iommu_init);

	#ifdef CONFIG_PCI
	/* Many VIA bridges seem to corrupt data for DAC. Disable it here */

	static __devinit void via_no_dac(struct pci_dev *dev)
	{
	if ((dev->class >> 8) == PCI_CLASS_BRIDGE_PCI && forbid_dac == 0) {
	dev_info(&dev->dev, "disabling DAC on VIA PCI bridge\n");
	forbid_dac = 1;
	}
	}
	DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_VIA, PCI_ANY_ID, via_no_dac);
	#endif