[IA64] Add Variable Page Size and IA64 Support in Intel IOMMU

The patch contains Intel IOMMU IA64 specific code. It defines new
machvec dig_vtd, hooks for IOMMU, DMAR table detection, cache line flush
function, etc.

For a generic kernel with CONFIG_DMAR=y, if Intel IOMMU is detected,
dig_vtd is used for machinve vector. Otherwise, kernel falls back to
dig machine vector. Kernel parameter "machvec=dig" or "intel_iommu=off"
can be used to force kernel to boot dig machine vector.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

arch/ia64/kernel/pci-dma.c

@@ -0,0 +1,129 @@
+/*
+ * Dynamic DMA mapping support.
+ */
+
+#include <linux/types.h>
+#include <linux/mm.h>
+#include <linux/string.h>
+#include <linux/pci.h>
+#include <linux/module.h>
+#include <linux/dmar.h>
+#include <asm/iommu.h>
+#include <asm/machvec.h>
+#include <linux/dma-mapping.h>
+
+#include <asm/machvec.h>
+#include <asm/system.h>
+
+#ifdef CONFIG_DMAR
+
+#include <linux/kernel.h>
+#include <linux/string.h>
+
+#include <asm/page.h>
+#include <asm/iommu.h>
+
+dma_addr_t bad_dma_address __read_mostly;
+EXPORT_SYMBOL(bad_dma_address);
+
+static int iommu_sac_force __read_mostly;
+
+int no_iommu __read_mostly;
+#ifdef CONFIG_IOMMU_DEBUG
+int force_iommu __read_mostly = 1;
+#else
+int force_iommu __read_mostly;
+#endif
+
+/* Set this to 1 if there is a HW IOMMU in the system */
+int iommu_detected __read_mostly;
+
+/* Dummy device used for NULL arguments (normally ISA). Better would
+   be probably a smaller DMA mask, but this is bug-to-bug compatible
+   to i386. */
+struct device fallback_dev = {
+	.bus_id = "fallback device",
+	.coherent_dma_mask = DMA_32BIT_MASK,
+	.dma_mask = &fallback_dev.coherent_dma_mask,
+};
+
+void __init pci_iommu_alloc(void)
+{
+	/*
+	 * The order of these functions is important for
+	 * fall-back/fail-over reasons
+	 */
+	detect_intel_iommu();
+
+#ifdef CONFIG_SWIOTLB
+	pci_swiotlb_init();
+#endif
+}
+
+static int __init pci_iommu_init(void)
+{
+	if (iommu_detected)
+		intel_iommu_init();
+
+	return 0;
+}
+
+/* Must execute after PCI subsystem */
+fs_initcall(pci_iommu_init);
+
+void pci_iommu_shutdown(void)
+{
+	return;
+}
+
+void __init
+iommu_dma_init(void)
+{
+	return;
+}
+
+struct dma_mapping_ops *dma_ops;
+EXPORT_SYMBOL(dma_ops);
+
+int iommu_dma_supported(struct device *dev, u64 mask)
+{
+	struct dma_mapping_ops *ops = get_dma_ops(dev);
+
+#ifdef CONFIG_PCI
+	if (mask > 0xffffffff && forbid_dac > 0) {
+		dev_info(dev, "Disallowing DAC for device\n");
+		return 0;
+	}
+#endif
+
+	if (ops->dma_supported_op)
+		return ops->dma_supported_op(dev, mask);
+
+	/* Copied from i386. Doesn't make much sense, because it will
+	   only work for pci_alloc_coherent.
+	   The caller just has to use GFP_DMA in this case. */
+	if (mask < DMA_24BIT_MASK)
+		return 0;
+
+	/* Tell the device to use SAC when IOMMU force is on.  This
+	   allows the driver to use cheaper accesses in some cases.
+
+	   Problem with this is that if we overflow the IOMMU area and
+	   return DAC as fallback address the device may not handle it
+	   correctly.
+
+	   As a special case some controllers have a 39bit address
+	   mode that is as efficient as 32bit (aic79xx). Don't force
+	   SAC for these.  Assume all masks <= 40 bits are of this
+	   type. Normally this doesn't make any difference, but gives
+	   more gentle handling of IOMMU overflow. */
+	if (iommu_sac_force && (mask >= DMA_40BIT_MASK)) {
+		dev_info(dev, "Force SAC with mask %lx\n", mask);
+		return 0;
+	}
+
+	return 1;
+}
+EXPORT_SYMBOL(iommu_dma_supported);
+
+#endif