patch-2.3.35 linux/arch/sparc64/kernel/iommu_common.c

• Lines: 234
• Date: Mon Dec 20 22:05:52 1999
• Orig file: v2.3.34/linux/arch/sparc64/kernel/iommu_common.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.34/linux/arch/sparc64/kernel/iommu_common.c linux/arch/sparc64/kernel/iommu_common.c
@@ -0,0 +1,233 @@
+/* $Id: iommu_common.c,v 1.2 1999/12/19 09:17:53 davem Exp $
+ * iommu_common.c: UltraSparc SBUS/PCI common iommu code.
+ *
+ * Copyright (C) 1999 David S. Miller (davem@redhat.com)
+ */
+
+#include "iommu_common.h"
+
+/* You are _strongly_ advised to enable the following debugging code
+ * any time you make changes to the sg code below, run it for a while
+ * with filesystems mounted read-only before buying the farm... -DaveM
+ */
+
+#ifdef VERIFY_SG
+int verify_lengths(struct scatterlist *sg, int nents, int npages)
+{
+	int sg_len, dma_len;
+	int i, pgcount;
+
+	sg_len = 0;
+	for (i = 0; i < nents; i++)
+		sg_len += sg[i].length;
+
+	dma_len = 0;
+	for (i = 0; i < nents && sg[i].dvma_length; i++)
+		dma_len += sg[i].dvma_length;
+
+	if (sg_len != dma_len) {
+		printk("verify_lengths: Error, different, sg[%d] dma[%d]\n",
+		       sg_len, dma_len);
+		return -1;
+	}
+
+	pgcount = 0;
+	for (i = 0; i < nents && sg[i].dvma_length; i++) {
+		unsigned long start, end;
+
+		start = sg[i].dvma_address;
+		start = start & PAGE_MASK;
+
+		end = sg[i].dvma_address + sg[i].dvma_length;
+		end = (end + (PAGE_SIZE - 1)) & PAGE_MASK;
+
+		pgcount += ((end - start) >> PAGE_SHIFT);
+	}
+
+	if (pgcount != npages) {
+		printk("verify_langths: Error, page count wrong, "
+		       "npages[%d] pgcount[%d]\n",
+		       npages, pgcount);
+		return -1;
+	}
+
+	/* This test passes... */
+	return 0;
+}
+
+int verify_one_map(struct scatterlist *dma_sg, struct scatterlist **__sg, int nents, iopte_t **__iopte)
+{
+	struct scatterlist *sg = *__sg;
+	iopte_t *iopte = *__iopte;
+	int retval = 0;
+	u32 dlen = dma_sg->dvma_length;
+	u32 daddr = dma_sg->dvma_address;
+	unsigned int sglen;
+	unsigned long sgaddr;
+
+	sglen = sg->length;
+	sgaddr = (unsigned long) sg->address;
+	while (dlen > 0) {
+		unsigned long paddr;
+
+		/* SG and DMA_SG must begin at the same sub-page boundary. */
+		if ((sgaddr & ~PAGE_MASK) != (daddr & ~PAGE_MASK)) {
+			printk("verify_one_map: Wrong start offset "
+			       "sg[%08lx] dma[%08x]\n",
+			       sgaddr, daddr);
+			retval = -nents;
+			goto out;
+		}
+
+		/* Verify the IOPTE points to the right page. */
+		paddr = iopte_val(*iopte) & IOPTE_PAGE;
+		if ((paddr + PAGE_OFFSET) != (sgaddr & PAGE_MASK)) {
+			printk("verify_one_map: IOPTE[%08lx] maps the "
+			       "wrong page, should be [%08lx]\n",
+			       iopte_val(*iopte), (sgaddr & PAGE_MASK) - PAGE_OFFSET);
+			retval = -nents;
+			goto out;
+		}
+
+		/* If this SG crosses a page, adjust to that next page
+		 * boundary and loop.
+		 */
+		if ((sgaddr & PAGE_MASK) ^ ((sgaddr + sglen - 1) & PAGE_MASK)) {
+			unsigned long next_page, diff;
+
+			next_page = (sgaddr + PAGE_SIZE) & PAGE_MASK;
+			diff = next_page - sgaddr;
+			sgaddr += diff;
+			daddr += diff;
+			sglen -= diff;
+			dlen -= diff;
+			if (dlen > 0)
+				iopte++;
+			continue;
+		}
+
+		/* SG wholly consumed within this page. */
+		daddr += sglen;
+		dlen -= sglen;
+
+		if (dlen > 0 && ((daddr & ~PAGE_MASK) == 0))
+			iopte++;
+
+		sg++;
+		sgaddr = (unsigned long) sg->address;
+		sglen = sg->length;
+	}
+	if (dlen < 0) {
+		/* Transfer overrun, big problems. */
+		printk("verify_one_map: Transfer overrun by %d bytes.\n",
+		       -dlen);
+		retval = -nents;
+	} else {
+		/* Advance to next dma_sg implies that the next iopte will
+		 * begin it.
+		 */
+		iopte++;
+	}
+
+out:
+	*__sg = sg;
+	*__iopte = iopte;
+	return retval;
+}
+
+int verify_maps(struct scatterlist *sg, int nents, iopte_t *iopte)
+{
+	struct scatterlist *dma_sg = sg;
+	struct scatterlist *orig_dma_sg = dma_sg;
+	int orig_nents = nents;
+
+	for (;;) {
+		nents = verify_one_map(dma_sg, &sg, nents, &iopte);
+		if (nents <= 0)
+			break;
+		dma_sg++;
+		if (dma_sg->dvma_length == 0)
+			break;
+	}
+
+	if (nents > 0) {
+		printk("verify_maps: dma maps consumed by some sgs remain (%d)\n",
+		       nents);
+		return -1;
+	}
+
+	if (nents < 0) {
+		printk("verify_maps: Error, messed up mappings, "
+		       "at sg %d dma_sg %d\n",
+		       (int) (orig_nents + nents), (int) (dma_sg - orig_dma_sg));
+		return -1;
+	}
+
+	/* This test passes... */
+	return 0;
+}
+
+void verify_sglist(struct scatterlist *sg, int nents, iopte_t *iopte, int npages)
+{
+	if (verify_lengths(sg, nents, npages) < 0 ||
+	    verify_maps(sg, nents, iopte) < 0) {
+		int i;
+
+		printk("verify_sglist: Crap, messed up mappings, dumping, iodma at %08x.\n",
+		       (u32) (sg->dvma_address & PAGE_MASK));
+		for (i = 0; i < nents; i++) {
+			printk("sg(%d): address(%p) length(%x) "
+			       "dma_address[%08x] dma_length[%08x]\n",
+			       i,
+			       sg[i].address, sg[i].length,
+			       sg[i].dvma_address, sg[i].dvma_length);
+		}
+	}
+
+	/* Seems to be ok */
+}
+#endif
+
+/* Two addresses are "virtually contiguous" if and only if:
+ * 1) They are equal, or...
+ * 2) They are both on a page boundry
+ */
+#define VCONTIG(__X, __Y)	(((__X) == (__Y)) || \
+				 (((__X) | (__Y)) << (64UL - PAGE_SHIFT)) == 0UL)
+
+unsigned long prepare_sg(struct scatterlist *sg, int nents)
+{
+	struct scatterlist *dma_sg = sg;
+	unsigned long prev;
+	u32 dent_addr, dent_len;
+
+	prev  = (unsigned long) sg->address;
+	prev += (unsigned long) (dent_len = sg->length);
+	dent_addr = (u32) ((unsigned long)sg->address & (PAGE_SIZE - 1UL));
+	while (--nents) {
+		unsigned long addr;
+
+		sg++;
+		addr = (unsigned long) sg->address;
+		if (! VCONTIG(prev, addr)) {
+			dma_sg->dvma_address = dent_addr;
+			dma_sg->dvma_length = dent_len;
+			dma_sg++;
+
+			dent_addr = ((dent_addr +
+				      dent_len +
+				      (PAGE_SIZE - 1UL)) >> PAGE_SHIFT);
+			dent_addr <<= PAGE_SHIFT;
+			dent_addr += addr & (PAGE_SIZE - 1UL);
+			dent_len = 0;
+		}
+		dent_len += sg->length;
+		prev = addr + sg->length;
+	}
+	dma_sg->dvma_address = dent_addr;
+	dma_sg->dvma_length = dent_len;
+
+	return ((unsigned long) dent_addr +
+		(unsigned long) dent_len +
+		(PAGE_SIZE - 1UL)) >> PAGE_SHIFT;
+}