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- // SPDX-License-Identifier: GPL-2.0
- #include <linux/pci.h>
- #include <linux/cache.h>
- #include <linux/init.h>
- #include <linux/swiotlb.h>
- #include <linux/memblock.h>
- #include <linux/dma-direct.h>
- #include <linux/mem_encrypt.h>
- #include <asm/iommu.h>
- #include <asm/swiotlb.h>
- #include <asm/dma.h>
- #include <asm/xen/swiotlb-xen.h>
- #include <asm/iommu_table.h>
- int swiotlb __read_mostly;
- /*
- * 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_override(void)
- {
- if (swiotlb_force == SWIOTLB_FORCE)
- swiotlb = 1;
- return swiotlb;
- }
- IOMMU_INIT_FINISH(pci_swiotlb_detect_override,
- pci_xen_swiotlb_detect,
- pci_swiotlb_init,
- pci_swiotlb_late_init);
- /*
- * If 4GB or more detected (and iommu=off not set) or if SME is active
- * then set swiotlb to 1 and return 1.
- */
- int __init pci_swiotlb_detect_4gb(void)
- {
- /* don't initialize swiotlb if iommu=off (no_iommu=1) */
- if (!no_iommu && max_possible_pfn > MAX_DMA32_PFN)
- swiotlb = 1;
- /*
- * If SME is active then swiotlb will be set to 1 so that bounce
- * buffers are allocated and used for devices that do not support
- * the addressing range required for the encryption mask.
- */
- if (sme_active())
- swiotlb = 1;
- return swiotlb;
- }
- IOMMU_INIT(pci_swiotlb_detect_4gb,
- pci_swiotlb_detect_override,
- pci_swiotlb_init,
- pci_swiotlb_late_init);
- void __init pci_swiotlb_init(void)
- {
- if (swiotlb)
- swiotlb_init(0);
- }
- void __init pci_swiotlb_late_init(void)
- {
- /* An IOMMU turned us off. */
- if (!swiotlb)
- swiotlb_exit();
- else {
- printk(KERN_INFO "PCI-DMA: "
- "Using software bounce buffering for IO (SWIOTLB)\n");
- swiotlb_print_info();
- }
- }
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