// SPDX-License-Identifier: GPL-2.0
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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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