From 8e4bff4cab0ddac6060645b0715210484d02ff40 Mon Sep 17 00:00:00 2001
From: Yuval Adam <_@yuv.al>
Date: Wed, 30 Aug 2017 08:25:59 +0000
Subject: Initial file dump from open source release

---
 arch/x86/kernel/pci-swiotlb.c | 109 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 109 insertions(+)
 create mode 100644 arch/x86/kernel/pci-swiotlb.c

(limited to 'arch/x86/kernel/pci-swiotlb.c')

diff --git a/arch/x86/kernel/pci-swiotlb.c b/arch/x86/kernel/pci-swiotlb.c
new file mode 100644
index 00000000..6c483ba9
--- /dev/null
+++ b/arch/x86/kernel/pci-swiotlb.c
@@ -0,0 +1,109 @@
+/* Glue code to lib/swiotlb.c */
+
+#include <linux/pci.h>
+#include <linux/cache.h>
+#include <linux/module.h>
+#include <linux/swiotlb.h>
+#include <linux/bootmem.h>
+#include <linux/dma-mapping.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;
+
+static void *x86_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
+					dma_addr_t *dma_handle, gfp_t flags,
+					struct dma_attrs *attrs)
+{
+	void *vaddr;
+
+	vaddr = dma_generic_alloc_coherent(hwdev, size, dma_handle, flags,
+					   attrs);
+	if (vaddr)
+		return vaddr;
+
+	return swiotlb_alloc_coherent(hwdev, size, dma_handle, flags);
+}
+
+static void x86_swiotlb_free_coherent(struct device *dev, size_t size,
+				      void *vaddr, dma_addr_t dma_addr,
+				      struct dma_attrs *attrs)
+{
+	swiotlb_free_coherent(dev, size, vaddr, dma_addr);
+}
+
+static struct dma_map_ops swiotlb_dma_ops = {
+	.mapping_error = swiotlb_dma_mapping_error,
+	.alloc = x86_swiotlb_alloc_coherent,
+	.free = x86_swiotlb_free_coherent,
+	.sync_single_for_cpu = swiotlb_sync_single_for_cpu,
+	.sync_single_for_device = swiotlb_sync_single_for_device,
+	.sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
+	.sync_sg_for_device = swiotlb_sync_sg_for_device,
+	.map_sg = swiotlb_map_sg_attrs,
+	.unmap_sg = swiotlb_unmap_sg_attrs,
+	.map_page = swiotlb_map_page,
+	.unmap_page = swiotlb_unmap_page,
+	.dma_supported = NULL,
+};
+
+/*
+ * 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)
+{
+	int use_swiotlb = swiotlb | swiotlb_force;
+
+	if (swiotlb_force)
+		swiotlb = 1;
+
+	return use_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) 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
+	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);
+		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();
+	}
+}
-- 
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