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-rw-r--r--arch/powerpc/kernel/dma-iommu.c221
1 files changed, 221 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/dma-iommu.c b/arch/powerpc/kernel/dma-iommu.c
new file mode 100644
index 0000000000..8920862ffd
--- /dev/null
+++ b/arch/powerpc/kernel/dma-iommu.c
@@ -0,0 +1,221 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
+ *
+ * Provide default implementations of the DMA mapping callbacks for
+ * busses using the iommu infrastructure
+ */
+
+#include <linux/dma-direct.h>
+#include <linux/pci.h>
+#include <asm/iommu.h>
+
+#ifdef CONFIG_ARCH_HAS_DMA_MAP_DIRECT
+#define can_map_direct(dev, addr) \
+ ((dev)->bus_dma_limit >= phys_to_dma((dev), (addr)))
+
+bool arch_dma_map_page_direct(struct device *dev, phys_addr_t addr)
+{
+ if (likely(!dev->bus_dma_limit))
+ return false;
+
+ return can_map_direct(dev, addr);
+}
+
+#define is_direct_handle(dev, h) ((h) >= (dev)->archdata.dma_offset)
+
+bool arch_dma_unmap_page_direct(struct device *dev, dma_addr_t dma_handle)
+{
+ if (likely(!dev->bus_dma_limit))
+ return false;
+
+ return is_direct_handle(dev, dma_handle);
+}
+
+bool arch_dma_map_sg_direct(struct device *dev, struct scatterlist *sg,
+ int nents)
+{
+ struct scatterlist *s;
+ int i;
+
+ if (likely(!dev->bus_dma_limit))
+ return false;
+
+ for_each_sg(sg, s, nents, i) {
+ if (!can_map_direct(dev, sg_phys(s) + s->offset + s->length))
+ return false;
+ }
+
+ return true;
+}
+
+bool arch_dma_unmap_sg_direct(struct device *dev, struct scatterlist *sg,
+ int nents)
+{
+ struct scatterlist *s;
+ int i;
+
+ if (likely(!dev->bus_dma_limit))
+ return false;
+
+ for_each_sg(sg, s, nents, i) {
+ if (!is_direct_handle(dev, s->dma_address + s->length))
+ return false;
+ }
+
+ return true;
+}
+#endif /* CONFIG_ARCH_HAS_DMA_MAP_DIRECT */
+
+/*
+ * Generic iommu implementation
+ */
+
+/* Allocates a contiguous real buffer and creates mappings over it.
+ * Returns the virtual address of the buffer and sets dma_handle
+ * to the dma address (mapping) of the first page.
+ */
+static void *dma_iommu_alloc_coherent(struct device *dev, size_t size,
+ dma_addr_t *dma_handle, gfp_t flag,
+ unsigned long attrs)
+{
+ return iommu_alloc_coherent(dev, get_iommu_table_base(dev), size,
+ dma_handle, dev->coherent_dma_mask, flag,
+ dev_to_node(dev));
+}
+
+static void dma_iommu_free_coherent(struct device *dev, size_t size,
+ void *vaddr, dma_addr_t dma_handle,
+ unsigned long attrs)
+{
+ iommu_free_coherent(get_iommu_table_base(dev), size, vaddr, dma_handle);
+}
+
+/* Creates TCEs for a user provided buffer. The user buffer must be
+ * contiguous real kernel storage (not vmalloc). The address passed here
+ * comprises a page address and offset into that page. The dma_addr_t
+ * returned will point to the same byte within the page as was passed in.
+ */
+static dma_addr_t dma_iommu_map_page(struct device *dev, struct page *page,
+ unsigned long offset, size_t size,
+ enum dma_data_direction direction,
+ unsigned long attrs)
+{
+ return iommu_map_page(dev, get_iommu_table_base(dev), page, offset,
+ size, dma_get_mask(dev), direction, attrs);
+}
+
+
+static void dma_iommu_unmap_page(struct device *dev, dma_addr_t dma_handle,
+ size_t size, enum dma_data_direction direction,
+ unsigned long attrs)
+{
+ iommu_unmap_page(get_iommu_table_base(dev), dma_handle, size, direction,
+ attrs);
+}
+
+
+static int dma_iommu_map_sg(struct device *dev, struct scatterlist *sglist,
+ int nelems, enum dma_data_direction direction,
+ unsigned long attrs)
+{
+ return ppc_iommu_map_sg(dev, get_iommu_table_base(dev), sglist, nelems,
+ dma_get_mask(dev), direction, attrs);
+}
+
+static void dma_iommu_unmap_sg(struct device *dev, struct scatterlist *sglist,
+ int nelems, enum dma_data_direction direction,
+ unsigned long attrs)
+{
+ ppc_iommu_unmap_sg(get_iommu_table_base(dev), sglist, nelems,
+ direction, attrs);
+}
+
+static bool dma_iommu_bypass_supported(struct device *dev, u64 mask)
+{
+ struct pci_dev *pdev = to_pci_dev(dev);
+ struct pci_controller *phb = pci_bus_to_host(pdev->bus);
+
+ if (iommu_fixed_is_weak || !phb->controller_ops.iommu_bypass_supported)
+ return false;
+ return phb->controller_ops.iommu_bypass_supported(pdev, mask);
+}
+
+/* We support DMA to/from any memory page via the iommu */
+int dma_iommu_dma_supported(struct device *dev, u64 mask)
+{
+ struct iommu_table *tbl;
+
+ if (dev_is_pci(dev) && dma_iommu_bypass_supported(dev, mask)) {
+ /*
+ * dma_iommu_bypass_supported() sets dma_max when there is
+ * 1:1 mapping but it is somehow limited.
+ * ibm,pmemory is one example.
+ */
+ dev->dma_ops_bypass = dev->bus_dma_limit == 0;
+ if (!dev->dma_ops_bypass)
+ dev_warn(dev,
+ "iommu: 64-bit OK but direct DMA is limited by %llx\n",
+ dev->bus_dma_limit);
+ else
+ dev_dbg(dev, "iommu: 64-bit OK, using fixed ops\n");
+ return 1;
+ }
+
+ tbl = get_iommu_table_base(dev);
+
+ if (!tbl) {
+ dev_err(dev, "Warning: IOMMU dma not supported: mask 0x%08llx, table unavailable\n", mask);
+ return 0;
+ }
+
+ if (tbl->it_offset > (mask >> tbl->it_page_shift)) {
+ dev_info(dev, "Warning: IOMMU offset too big for device mask\n");
+ dev_info(dev, "mask: 0x%08llx, table offset: 0x%08lx\n",
+ mask, tbl->it_offset << tbl->it_page_shift);
+ return 0;
+ }
+
+ dev_dbg(dev, "iommu: not 64-bit, using default ops\n");
+ dev->dma_ops_bypass = false;
+ return 1;
+}
+
+u64 dma_iommu_get_required_mask(struct device *dev)
+{
+ struct iommu_table *tbl = get_iommu_table_base(dev);
+ u64 mask;
+
+ if (dev_is_pci(dev)) {
+ u64 bypass_mask = dma_direct_get_required_mask(dev);
+
+ if (dma_iommu_dma_supported(dev, bypass_mask)) {
+ dev_info(dev, "%s: returning bypass mask 0x%llx\n", __func__, bypass_mask);
+ return bypass_mask;
+ }
+ }
+
+ if (!tbl)
+ return 0;
+
+ mask = 1ULL << (fls_long(tbl->it_offset + tbl->it_size) +
+ tbl->it_page_shift - 1);
+ mask += mask - 1;
+
+ return mask;
+}
+
+const struct dma_map_ops dma_iommu_ops = {
+ .alloc = dma_iommu_alloc_coherent,
+ .free = dma_iommu_free_coherent,
+ .map_sg = dma_iommu_map_sg,
+ .unmap_sg = dma_iommu_unmap_sg,
+ .dma_supported = dma_iommu_dma_supported,
+ .map_page = dma_iommu_map_page,
+ .unmap_page = dma_iommu_unmap_page,
+ .get_required_mask = dma_iommu_get_required_mask,
+ .mmap = dma_common_mmap,
+ .get_sgtable = dma_common_get_sgtable,
+ .alloc_pages = dma_common_alloc_pages,
+ .free_pages = dma_common_free_pages,
+};