[patch 3/5] ia64: make IOMMU respect the segment boundary limits

[akpm@linux-foundation.org]

From: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>

IA64's IOMMU implementation allocates memory areas spanning LLD's segment
boundary limit.  It forces low level drivers to have a workaround to adjust
scatter lists that the IOMMU builds.

We are in the process of making all the IOMMUs respect the segment boundary
limits to remove such work around in LLDs.  This patch is for IA64's IOMMU.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/ia64/Kconfig               |    3 +
 arch/ia64/hp/common/sba_iommu.c |   56 ++++++++++++++++++++----------
 2 files changed, 42 insertions(+), 17 deletions(-)

diff -puN arch/ia64/Kconfig~ia64-make-iommu-respect-the-segment-boundary-limits arch/ia64/Kconfig
--- a/arch/ia64/Kconfig~ia64-make-iommu-respect-the-segment-boundary-limits
+++ a/arch/ia64/Kconfig
@@ -622,6 +622,9 @@ config IRQ_PER_CPU
 	bool
 	default y
 
+config IOMMU_HELPER
+	def_bool (IA64_HP_ZX1 || IA64_HP_ZX1_SWIOTLB || IA64_GENERIC)
+
 source "arch/ia64/hp/sim/Kconfig"
 
 source "arch/ia64/Kconfig.debug"
diff -puN arch/ia64/hp/common/sba_iommu.c~ia64-make-iommu-respect-the-segment-boundary-limits arch/ia64/hp/common/sba_iommu.c
--- a/arch/ia64/hp/common/sba_iommu.c~ia64-make-iommu-respect-the-segment-boundary-limits
+++ a/arch/ia64/hp/common/sba_iommu.c
@@ -35,6 +35,7 @@
 #include <linux/nodemask.h>
 #include <linux/bitops.h>         /* hweight64() */
 #include <linux/crash_dump.h>
+#include <linux/iommu-helper.h>
 
 #include <asm/delay.h>		/* ia64_get_itc() */
 #include <asm/io.h>
@@ -460,6 +461,13 @@ get_iovp_order (unsigned long size)
 	return order;
 }
 
+static unsigned long ptr_to_pide(struct ioc *ioc, unsigned long *res_ptr,
+				 unsigned int bitshiftcnt)
+{
+	return (((unsigned long)res_ptr - (unsigned long)ioc->res_map) << 3)
+		+ bitshiftcnt;
+}
+
 /**
  * sba_search_bitmap - find free space in IO PDIR resource bitmap
  * @ioc: IO MMU structure which owns the pdir we are interested in.
@@ -471,15 +479,25 @@ get_iovp_order (unsigned long size)
  * Cool perf optimization: search for log2(size) bits at a time.
  */
 static SBA_INLINE unsigned long
-sba_search_bitmap(struct ioc *ioc, unsigned long bits_wanted, int use_hint)
+sba_search_bitmap(struct ioc *ioc, struct device *dev,
+		  unsigned long bits_wanted, int use_hint)
 {
 	unsigned long *res_ptr;
 	unsigned long *res_end = (unsigned long *) &(ioc->res_map[ioc->res_size]);
-	unsigned long flags, pide = ~0UL;
+	unsigned long flags, pide = ~0UL, tpide;
+	unsigned long boundary_size;
+	unsigned long shift;
+	int ret;
 
 	ASSERT(((unsigned long) ioc->res_hint & (sizeof(unsigned long) - 1UL)) = 0);
 	ASSERT(res_ptr < res_end);
 
+	boundary_size = (unsigned long long)dma_get_seg_boundary(dev) + 1;
+	boundary_size = ALIGN(boundary_size, 1ULL << iovp_shift) >> iovp_shift;
+
+	BUG_ON(ioc->ibase & ~iovp_mask);
+	shift = ioc->ibase >> iovp_shift;
+
 	spin_lock_irqsave(&ioc->res_lock, flags);
 
 	/* Allow caller to force a search through the entire resource space */
@@ -504,9 +522,7 @@ sba_search_bitmap(struct ioc *ioc, unsig
 			if (likely(*res_ptr != ~0UL)) {
 				bitshiftcnt = ffz(*res_ptr);
 				*res_ptr |= (1UL << bitshiftcnt);
-				pide = ((unsigned long)res_ptr - (unsigned long)ioc->res_map);
-				pide <<= 3;	/* convert to bit address */
-				pide += bitshiftcnt;
+				pide = ptr_to_pide(ioc, res_ptr, bitshiftcnt);
 				ioc->res_bitshift = bitshiftcnt + bits_wanted;
 				goto found_it;
 			}
@@ -535,11 +551,13 @@ sba_search_bitmap(struct ioc *ioc, unsig
 			DBG_RES("    %p %lx %lx\n", res_ptr, mask, *res_ptr);
 			ASSERT(0 != mask);
 			for (; mask ; mask <<= o, bitshiftcnt += o) {
-				if(0 = ((*res_ptr) & mask)) {
+				tpide = ptr_to_pide(ioc, res_ptr, bitshiftcnt);
+				ret = iommu_is_span_boundary(tpide, bits_wanted,
+							     shift,
+							     boundary_size);
+				if ((0 = ((*res_ptr) & mask)) && !ret) {
 					*res_ptr |= mask;     /* mark resources busy! */
-					pide = ((unsigned long)res_ptr - (unsigned long)ioc->res_map);
-					pide <<= 3;	/* convert to bit address */
-					pide += bitshiftcnt;
+					pide = tpide;
 					ioc->res_bitshift = bitshiftcnt + bits_wanted;
 					goto found_it;
 				}
@@ -560,6 +578,11 @@ sba_search_bitmap(struct ioc *ioc, unsig
 		end = res_end - qwords;
 
 		for (; res_ptr < end; res_ptr++) {
+			tpide = ptr_to_pide(ioc, res_ptr, 0);
+			ret = iommu_is_span_boundary(tpide, bits_wanted,
+						     shift, boundary_size);
+			if (ret)
+				goto next_ptr;
 			for (i = 0 ; i < qwords ; i++) {
 				if (res_ptr[i] != 0)
 					goto next_ptr;
@@ -572,8 +595,7 @@ sba_search_bitmap(struct ioc *ioc, unsig
 				res_ptr[i] = ~0UL;
 			res_ptr[i] |= RESMAP_MASK(bits);
 
-			pide = ((unsigned long)res_ptr - (unsigned long)ioc->res_map);
-			pide <<= 3;	/* convert to bit address */
+			pide = tpide;
 			res_ptr += qwords;
 			ioc->res_bitshift = bits;
 			goto found_it;
@@ -605,7 +627,7 @@ found_it:
  * resource bit map.
  */
 static int
-sba_alloc_range(struct ioc *ioc, size_t size)
+sba_alloc_range(struct ioc *ioc, struct device *dev, size_t size)
 {
 	unsigned int pages_needed = size >> iovp_shift;
 #ifdef PDIR_SEARCH_TIMING
@@ -622,9 +644,9 @@ sba_alloc_range(struct ioc *ioc, size_t 
 	/*
 	** "seek and ye shall find"...praying never hurts either...
 	*/
-	pide = sba_search_bitmap(ioc, pages_needed, 1);
+	pide = sba_search_bitmap(ioc, dev, pages_needed, 1);
 	if (unlikely(pide >= (ioc->res_size << 3))) {
-		pide = sba_search_bitmap(ioc, pages_needed, 0);
+		pide = sba_search_bitmap(ioc, dev, pages_needed, 0);
 		if (unlikely(pide >= (ioc->res_size << 3))) {
 #if DELAYED_RESOURCE_CNT > 0
 			unsigned long flags;
@@ -653,7 +675,7 @@ sba_alloc_range(struct ioc *ioc, size_t 
 			}
 			spin_unlock_irqrestore(&ioc->saved_lock, flags);
 
-			pide = sba_search_bitmap(ioc, pages_needed, 0);
+			pide = sba_search_bitmap(ioc, dev, pages_needed, 0);
 			if (unlikely(pide >= (ioc->res_size << 3)))
 				panic(__FILE__ ": I/O MMU @ %p is out of mapping resources\n",
 				      ioc->ioc_hpa);
@@ -936,7 +958,7 @@ sba_map_single(struct device *dev, void 
 	spin_unlock_irqrestore(&ioc->res_lock, flags);
 #endif
 
-	pide = sba_alloc_range(ioc, size);
+	pide = sba_alloc_range(ioc, dev, size);
 
 	iovp = (dma_addr_t) pide << iovp_shift;
 
@@ -1373,7 +1395,7 @@ sba_coalesce_chunks(struct ioc *ioc, str
 		dma_len = (dma_len + dma_offset + ~iovp_mask) & iovp_mask;
 		ASSERT(dma_len <= DMA_CHUNK_SIZE);
 		dma_sg->dma_address = (dma_addr_t) (PIDE_FLAG
-			| (sba_alloc_range(ioc, dma_len) << iovp_shift)
+			| (sba_alloc_range(ioc, dev, dma_len) << iovp_shift)
 			| dma_offset);
 		n_mappings++;
 	}
_