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https://github.com/edk2-porting/linux-next.git
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55897af630
While the dma-direct code is (relatively) clean and simple we actually have to use the swiotlb ops for the mapping on many architectures due to devices with addressing limits. Instead of keeping two implementations around this commit allows the dma-direct implementation to call the swiotlb bounce buffering functions and thus share the guts of the mapping implementation. This also simplified the dma-mapping setup on a few architectures where we don't have to differenciate which implementation to use. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Tested-by: Jesper Dangaard Brouer <brouer@redhat.com> Tested-by: Tony Luck <tony.luck@intel.com>
80 lines
1.7 KiB
C
80 lines
1.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Glue code to lib/swiotlb.c */
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#include <linux/pci.h>
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#include <linux/cache.h>
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#include <linux/init.h>
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#include <linux/swiotlb.h>
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#include <linux/memblock.h>
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#include <linux/dma-direct.h>
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#include <linux/mem_encrypt.h>
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#include <asm/iommu.h>
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#include <asm/swiotlb.h>
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#include <asm/dma.h>
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#include <asm/xen/swiotlb-xen.h>
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#include <asm/iommu_table.h>
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int swiotlb __read_mostly;
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/*
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* pci_swiotlb_detect_override - set swiotlb to 1 if necessary
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*
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* This returns non-zero if we are forced to use swiotlb (by the boot
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* option).
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*/
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int __init pci_swiotlb_detect_override(void)
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{
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if (swiotlb_force == SWIOTLB_FORCE)
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swiotlb = 1;
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return swiotlb;
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}
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IOMMU_INIT_FINISH(pci_swiotlb_detect_override,
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pci_xen_swiotlb_detect,
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pci_swiotlb_init,
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pci_swiotlb_late_init);
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/*
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* If 4GB or more detected (and iommu=off not set) or if SME is active
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* then set swiotlb to 1 and return 1.
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*/
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int __init pci_swiotlb_detect_4gb(void)
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{
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/* don't initialize swiotlb if iommu=off (no_iommu=1) */
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if (!no_iommu && max_possible_pfn > MAX_DMA32_PFN)
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swiotlb = 1;
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/*
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* If SME is active then swiotlb will be set to 1 so that bounce
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* buffers are allocated and used for devices that do not support
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* the addressing range required for the encryption mask.
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*/
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if (sme_active())
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swiotlb = 1;
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return swiotlb;
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}
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IOMMU_INIT(pci_swiotlb_detect_4gb,
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pci_swiotlb_detect_override,
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pci_swiotlb_init,
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pci_swiotlb_late_init);
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void __init pci_swiotlb_init(void)
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{
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if (swiotlb)
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swiotlb_init(0);
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}
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void __init pci_swiotlb_late_init(void)
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{
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/* An IOMMU turned us off. */
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if (!swiotlb)
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swiotlb_exit();
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else {
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printk(KERN_INFO "PCI-DMA: "
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"Using software bounce buffering for IO (SWIOTLB)\n");
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swiotlb_print_info();
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}
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}
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