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-rw-r--r--drivers/parisc/iommu-helpers.h182
1 files changed, 182 insertions, 0 deletions
diff --git a/drivers/parisc/iommu-helpers.h b/drivers/parisc/iommu-helpers.h
new file mode 100644
index 0000000000..c43f1a212a
--- /dev/null
+++ b/drivers/parisc/iommu-helpers.h
@@ -0,0 +1,182 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <linux/prefetch.h>
+
+/**
+ * iommu_fill_pdir - Insert coalesced scatter/gather chunks into the I/O Pdir.
+ * @ioc: The I/O Controller.
+ * @startsg: The scatter/gather list of coalesced chunks.
+ * @nents: The number of entries in the scatter/gather list.
+ * @hint: The DMA Hint.
+ *
+ * This function inserts the coalesced scatter/gather list chunks into the
+ * I/O Controller's I/O Pdir.
+ */
+static inline unsigned int
+iommu_fill_pdir(struct ioc *ioc, struct scatterlist *startsg, int nents,
+ unsigned long hint,
+ void (*iommu_io_pdir_entry)(__le64 *, space_t, unsigned long,
+ unsigned long))
+{
+ struct scatterlist *dma_sg = startsg; /* pointer to current DMA */
+ unsigned int n_mappings = 0;
+ unsigned long dma_offset = 0, dma_len = 0;
+ __le64 *pdirp = NULL;
+
+ /* Horrible hack. For efficiency's sake, dma_sg starts one
+ * entry below the true start (it is immediately incremented
+ * in the loop) */
+ dma_sg--;
+
+ while (nents-- > 0) {
+ unsigned long vaddr;
+ long size;
+
+ DBG_RUN_SG(" %d : %08lx %p/%05x\n", nents,
+ (unsigned long)sg_dma_address(startsg),
+ sg_virt(startsg), startsg->length
+ );
+
+
+ /*
+ ** Look for the start of a new DMA stream
+ */
+
+ if (sg_dma_address(startsg) & PIDE_FLAG) {
+ u32 pide = sg_dma_address(startsg) & ~PIDE_FLAG;
+
+ BUG_ON(pdirp && (dma_len != sg_dma_len(dma_sg)));
+
+ dma_sg++;
+
+ dma_len = sg_dma_len(startsg);
+ sg_dma_len(startsg) = 0;
+ dma_offset = (unsigned long) pide & ~IOVP_MASK;
+ n_mappings++;
+#if defined(ZX1_SUPPORT)
+ /* Pluto IOMMU IO Virt Address is not zero based */
+ sg_dma_address(dma_sg) = pide | ioc->ibase;
+#else
+ /* SBA, ccio, and dino are zero based.
+ * Trying to save a few CPU cycles for most users.
+ */
+ sg_dma_address(dma_sg) = pide;
+#endif
+ pdirp = &(ioc->pdir_base[pide >> IOVP_SHIFT]);
+ prefetchw(pdirp);
+ }
+
+ BUG_ON(pdirp == NULL);
+
+ vaddr = (unsigned long)sg_virt(startsg);
+ sg_dma_len(dma_sg) += startsg->length;
+ size = startsg->length + dma_offset;
+ dma_offset = 0;
+#ifdef IOMMU_MAP_STATS
+ ioc->msg_pages += startsg->length >> IOVP_SHIFT;
+#endif
+ do {
+ iommu_io_pdir_entry(pdirp, KERNEL_SPACE,
+ vaddr, hint);
+ vaddr += IOVP_SIZE;
+ size -= IOVP_SIZE;
+ pdirp++;
+ } while(unlikely(size > 0));
+ startsg++;
+ }
+ return(n_mappings);
+}
+
+
+/*
+** First pass is to walk the SG list and determine where the breaks are
+** in the DMA stream. Allocates PDIR entries but does not fill them.
+** Returns the number of DMA chunks.
+**
+** Doing the fill separate from the coalescing/allocation keeps the
+** code simpler. Future enhancement could make one pass through
+** the sglist do both.
+*/
+
+static inline unsigned int
+iommu_coalesce_chunks(struct ioc *ioc, struct device *dev,
+ struct scatterlist *startsg, int nents,
+ int (*iommu_alloc_range)(struct ioc *, struct device *, size_t))
+{
+ struct scatterlist *contig_sg; /* contig chunk head */
+ unsigned long dma_offset, dma_len; /* start/len of DMA stream */
+ unsigned int n_mappings = 0;
+ unsigned int max_seg_size = min(dma_get_max_seg_size(dev),
+ (unsigned)DMA_CHUNK_SIZE);
+ unsigned int max_seg_boundary = dma_get_seg_boundary(dev) + 1;
+ if (max_seg_boundary) /* check if the addition above didn't overflow */
+ max_seg_size = min(max_seg_size, max_seg_boundary);
+
+ while (nents > 0) {
+
+ /*
+ ** Prepare for first/next DMA stream
+ */
+ contig_sg = startsg;
+ dma_len = startsg->length;
+ dma_offset = startsg->offset;
+
+ /* PARANOID: clear entries */
+ sg_dma_address(startsg) = 0;
+ sg_dma_len(startsg) = 0;
+
+ /*
+ ** This loop terminates one iteration "early" since
+ ** it's always looking one "ahead".
+ */
+ while(--nents > 0) {
+ unsigned long prev_end, sg_start;
+
+ prev_end = (unsigned long)sg_virt(startsg) +
+ startsg->length;
+
+ startsg++;
+ sg_start = (unsigned long)sg_virt(startsg);
+
+ /* PARANOID: clear entries */
+ sg_dma_address(startsg) = 0;
+ sg_dma_len(startsg) = 0;
+
+ /*
+ ** First make sure current dma stream won't
+ ** exceed max_seg_size if we coalesce the
+ ** next entry.
+ */
+ if (unlikely(ALIGN(dma_len + dma_offset + startsg->length, IOVP_SIZE) >
+ max_seg_size))
+ break;
+
+ /*
+ * Next see if we can append the next chunk (i.e.
+ * it must end on one page and begin on another, or
+ * it must start on the same address as the previous
+ * entry ended.
+ */
+ if (unlikely((prev_end != sg_start) ||
+ ((prev_end | sg_start) & ~PAGE_MASK)))
+ break;
+
+ dma_len += startsg->length;
+ }
+
+ /*
+ ** End of DMA Stream
+ ** Terminate last VCONTIG block.
+ ** Allocate space for DMA stream.
+ */
+ sg_dma_len(contig_sg) = dma_len;
+ dma_len = ALIGN(dma_len + dma_offset, IOVP_SIZE);
+ sg_dma_address(contig_sg) =
+ PIDE_FLAG
+ | (iommu_alloc_range(ioc, dev, dma_len) << IOVP_SHIFT)
+ | dma_offset;
+ n_mappings++;
+ }
+
+ return n_mappings;
+}
+