1 files changed, 60 insertions, 0 deletions
diff --git a/arch/ia64/hp/common/hwsw_iommu.c b/arch/ia64/hp/common/hwsw_iommu.c
new file mode 100644
index 000000000..58969039b
--- /dev/null
+++ b/arch/ia64/hp/common/hwsw_iommu.c
@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2004 Hewlett-Packard Development Company, L.P.
+ *   Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
+ *
+ * This is a pseudo I/O MMU which dispatches to the hardware I/O MMU
+ * whenever possible.  We assume that the hardware I/O MMU requires
+ * full 32-bit addressability, as is the case, e.g., for HP zx1-based
+ * systems (there, the I/O MMU window is mapped at 3-4GB).  If a
+ * device doesn't provide full 32-bit addressability, we fall back on
+ * the sw I/O TLB.  This is good enough to let us support broken
+ * hardware such as soundcards which have a DMA engine that can
+ * address only 28 bits.
+ */
+
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <linux/swiotlb.h>
+#include <linux/export.h>
+#include <asm/machvec.h>
+
+extern const struct dma_map_ops sba_dma_ops;
+
+/* swiotlb declarations & definitions: */
+extern int swiotlb_late_init_with_default_size (size_t size);
+
+/*
+ * Note: we need to make the determination of whether or not to use
+ * the sw I/O TLB based purely on the device structure.  Anything else
+ * would be unreliable or would be too intrusive.
+ */
+static inline int use_swiotlb(struct device *dev)
+{
+	return dev && dev->dma_mask &&
+		!sba_dma_ops.dma_supported(dev, *dev->dma_mask);
+}
+
+const struct dma_map_ops *hwsw_dma_get_ops(struct device *dev)
+{
+	if (use_swiotlb(dev))
+		return &swiotlb_dma_ops;
+	return &sba_dma_ops;
+}
+EXPORT_SYMBOL(hwsw_dma_get_ops);
+
+void __init
+hwsw_init (void)
+{
+	/* default to a smallish 2MB sw I/O TLB */
+	if (swiotlb_late_init_with_default_size (2 * (1<<20)) != 0) {
+#ifdef CONFIG_IA64_GENERIC
+		/* Better to have normal DMA than panic */
+		printk(KERN_WARNING "%s: Failed to initialize software I/O TLB,"
+		       " reverting to hpzx1 platform vector\n", __func__);
+		machvec_init("hpzx1");
+#else
+		panic("Unable to initialize software I/O TLB services");
+#endif
+	}
+}