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Commit efa631c2 authored by Konrad Rzeszutek Wilk's avatar Konrad Rzeszutek Wilk Committed by H. Peter Anvin
Browse files

x86, swiotlb: Simplify SWIOTLB pci_swiotlb_detect routine. 



In 'pci_swiotlb_detect' we used to do two different things:
 a). If user provided 'iommu=soft' or 'swiotlb=force' we
     would set swiotlb=1 and return 1 (and forcing pci-dma.c
     to call pci_swiotlb_init() immediately).
 b). If 4GB or more would be detected and if user did not specify
     iommu=off, we would set 'swiotlb=1' and return whatever 'a)'
     figured out.

We simplify this by splitting a) and b) in two different routines.

CC: Fujita Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
LKML-Reference: <1282845485-8991-5-git-send-email-konrad.wilk@oracle.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
parent 5bef80a4

arch/x86/include/asm/iommu_table.h

+2 −2
Original line number Diff line number Diff line
@@ -64,10 +64,10 @@ struct iommu_table_entry { 
 * to stop detecting the other IOMMUs after yours has been detected.

 */

#define IOMMU_INIT_POST(_detect)					\

	__IOMMU_INIT(_detect, pci_swiotlb_detect,  0, 0, 0)

	__IOMMU_INIT(_detect, pci_swiotlb_detect_4gb,  0, 0, 0)



#define IOMMU_INIT_POST_FINISH(detect)					\

	__IOMMU_INIT(_detect, pci_swiotlb_detect,  0, 0, 1)

	__IOMMU_INIT(_detect, pci_swiotlb_detect_4gb,  0, 0, 1)



/*

 * A more sophisticated version of IOMMU_INIT. This variant requires:

arch/x86/include/asm/swiotlb.h

+11 −2
Original line number Diff line number Diff line
@@ -5,17 +5,26 @@ 


#ifdef CONFIG_SWIOTLB

extern int swiotlb;

extern int __init pci_swiotlb_detect(void);

extern int __init pci_swiotlb_detect_override(void);

extern int __init pci_swiotlb_detect_4gb(void);

extern void __init pci_swiotlb_init(void);

extern void __init pci_swiotlb_late_init(void);

#else

#define swiotlb 0

static inline int pci_swiotlb_detect(void)

static inline int pci_swiotlb_detect_override(void)

{

	return 0;

}

static inline int pci_swiotlb_detect_4gb(void)

{

	return 0;

}

static inline void pci_swiotlb_init(void)

{

}

static inline void pci_swiotlb_late_init(void)

{

}

#endif



static inline void dma_mark_clean(void *addr, size_t size) {}

arch/x86/kernel/pci-dma.c

+3 −1
Original line number Diff line number Diff line
@@ -133,9 +133,11 @@ void __init pci_iommu_alloc(void) 
	/* free the range so iommu could get some range less than 4G */

	dma32_free_bootmem();



	if (pci_xen_swiotlb_detect() || pci_swiotlb_detect())

	if (pci_xen_swiotlb_detect() || pci_swiotlb_detect_override())

		goto out;



	pci_swiotlb_detect_4gb();



	gart_iommu_hole_init();



	detect_calgary();

arch/x86/kernel/pci-swiotlb.c

+27 −6
Original line number Diff line number Diff line
@@ -41,24 +41,33 @@ static struct dma_map_ops swiotlb_dma_ops = { 
};



/*

 * pci_swiotlb_detect - set swiotlb to 1 if necessary

 * pci_swiotlb_detect_override - set swiotlb to 1 if necessary

 *

 * This returns non-zero if we are forced to use swiotlb (by the boot

 * option).

 */

int __init pci_swiotlb_detect(void)

int __init pci_swiotlb_detect_override(void)

{

	int use_swiotlb = swiotlb | swiotlb_force;



	if (swiotlb_force)

		swiotlb = 1;



	return use_swiotlb;

}



/*

 * if 4GB or more detected (and iommu=off not set) return 1

 * and set swiotlb to 1.

 */

int __init pci_swiotlb_detect_4gb(void)

{

	/* don't initialize swiotlb if iommu=off (no_iommu=1) */

#ifdef CONFIG_X86_64

	if (!no_iommu && max_pfn > MAX_DMA32_PFN)

		swiotlb = 1;

#endif

	if (swiotlb_force)

		swiotlb = 1;



	return use_swiotlb;

	return swiotlb;

}



void __init pci_swiotlb_init(void)
@@ -68,3 +77,15 @@ void __init pci_swiotlb_init(void) 
		dma_ops = &swiotlb_dma_ops;

	}

}



void __init pci_swiotlb_late_init(void)

{

	/* An IOMMU turned us off. */

	if (!swiotlb)

		swiotlb_free();

	else {

		printk(KERN_INFO "PCI-DMA: "

		       "Using software bounce buffering for IO (SWIOTLB)\n");

		swiotlb_print_info();

	}

}