Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 171 insertions, 0 deletions

diff --git a/drivers/parisc/iommu-helpers.h b/drivers/parisc/iommu-helpers.h
new file mode 100644
index 0000000..38d9e1a
--- /dev/null
+++ b/drivers/parisc/iommu-helpers.h
@@ -0,0 +1,171 @@
+/**
+ * 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)(u64 *, 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;
+	u64 *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/%05x %08lx/%05x\n", nents,
+			   (unsigned long)sg_dma_address(startsg), cnt,
+			   sg_virt_addr(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 = sg_virt_addr(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 scatterlist *startsg, int nents,
+		      int (*iommu_alloc_range)(struct ioc *, 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;
+
+	while (nents > 0) {
+
+		/*
+		** Prepare for first/next DMA stream
+		*/
+		contig_sg = startsg;
+		dma_len = startsg->length;
+		dma_offset = sg_virt_addr(startsg) & ~IOVP_MASK;
+
+		/* 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 prevstartsg_end, startsg_end;
+
+			prevstartsg_end = sg_virt_addr(startsg) +
+				startsg->length;
+
+			startsg++;
+			startsg_end = sg_virt_addr(startsg) + 
+				startsg->length;
+
+			/* PARANOID: clear entries */
+			sg_dma_address(startsg) = 0;
+			sg_dma_len(startsg) = 0;
+
+			/*
+			** First make sure current dma stream won't
+			** exceed DMA_CHUNK_SIZE if we coalesce the
+			** next entry.
+			*/   
+			if(unlikely(ROUNDUP(dma_len + dma_offset + startsg->length,
+					    IOVP_SIZE) > DMA_CHUNK_SIZE))
+				break;
+
+			/*
+			** Next see if we can append the next chunk (i.e.
+			** it must end on one page and begin on another
+			*/
+			if (unlikely(((prevstartsg_end | sg_virt_addr(startsg)) & ~PAGE_MASK) != 0))
+				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 = ROUNDUP(dma_len + dma_offset, IOVP_SIZE);
+		sg_dma_address(contig_sg) =
+			PIDE_FLAG 
+			| (iommu_alloc_range(ioc, dma_len) << IOVP_SHIFT)
+			| dma_offset;
+		n_mappings++;
+	}
+
+	return n_mappings;
+}
+