SPARC64: sg chaining support

This updates the sparc64 iommu/pci dma mappers to sg chaining.

Acked-by: David S. Miller <davem@davemloft.net>

Later updated to newer kernel with unified sparc64 iommu sg handling.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

2 files changed, 43 insertions, 28 deletions

diff --git a/arch/sparc64/kernel/iommu.c b/arch/sparc64/kernel/iommu.c
index b35a62167e9..db3ffcf7a12 100644
--- a/arch/sparc64/kernel/iommu.c
+++ b/arch/sparc64/kernel/iommu.c
@@ -10,6 +10,7 @@
 #include <linux/device.h>
 #include <linux/dma-mapping.h>
 #include <linux/errno.h>
+#include <linux/scatterlist.h>
 
 #ifdef CONFIG_PCI
 #include <linux/pci.h>
@@ -480,7 +481,7 @@ static inline void fill_sg(iopte_t *iopte, struct scatterlist *sg,
                            unsigned long iopte_protection)
 {
         struct scatterlist *dma_sg = sg;
-        struct scatterlist *sg_end = sg + nelems;
+        struct scatterlist *sg_end = sg_last(sg, nelems);
         int i;
 
         for (i = 0; i < nused; i++) {
@@ -515,7 +516,7 @@ static inline void fill_sg(iopte_t *iopte, struct scatterlist *sg,
                                         len -= (IO_PAGE_SIZE - (tmp & (IO_PAGE_SIZE - 1UL)));
                                         break;
                                 }
-                                sg++;
+                                sg = sg_next(sg);
                         }
 
                         pteval = iopte_protection | (pteval & IOPTE_PAGE);
@@ -528,24 +529,24 @@ static inline void fill_sg(iopte_t *iopte, struct scatterlist *sg,
                         }
 
                         pteval = (pteval & IOPTE_PAGE) + len;
-                        sg++;
+                        sg = sg_next(sg);
 
                         /* Skip over any tail mappings we've fully mapped,
                          * adjusting pteval along the way.  Stop when we
                          * detect a page crossing event.
                          */
-                        while (sg < sg_end &&
+                        while (sg != sg_end &&
                                (pteval << (64 - IO_PAGE_SHIFT)) != 0UL &&
                                (pteval == SG_ENT_PHYS_ADDRESS(sg)) &&
                                ((pteval ^
                                  (SG_ENT_PHYS_ADDRESS(sg) + sg->length - 1UL)) >> IO_PAGE_SHIFT) == 0UL) {
                                 pteval += sg->length;
-                                sg++;
+                                sg = sg_next(sg);
                         }
                         if ((pteval << (64 - IO_PAGE_SHIFT)) == 0UL)
                                 pteval = ~0UL;
                 } while (dma_npages != 0);
-                dma_sg++;
+                dma_sg = sg_next(dma_sg);
         }
 }
 
@@ -606,7 +607,7 @@ static int dma_4u_map_sg(struct device *dev, struct scatterlist *sglist,
         sgtmp = sglist;
         while (used && sgtmp->dma_length) {
                 sgtmp->dma_address += dma_base;
-                sgtmp++;
+                sgtmp = sg_next(sgtmp);
                 used--;
         }
         used = nelems - used;
@@ -642,6 +643,7 @@ static void dma_4u_unmap_sg(struct device *dev, struct scatterlist *sglist,
         struct strbuf *strbuf;
         iopte_t *base;
         unsigned long flags, ctx, i, npages;
+        struct scatterlist *sg, *sgprv;
         u32 bus_addr;
 
         if (unlikely(direction == DMA_NONE)) {
@@ -654,11 +656,14 @@ static void dma_4u_unmap_sg(struct device *dev, struct scatterlist *sglist,
 
         bus_addr = sglist->dma_address & IO_PAGE_MASK;
 
-        for (i = 1; i < nelems; i++)
-                if (sglist[i].dma_length == 0)
+        sgprv = NULL;
+        for_each_sg(sglist, sg, nelems, i) {
+                if (sg->dma_length == 0)
                         break;
-        i--;
-        npages = (IO_PAGE_ALIGN(sglist[i].dma_address + sglist[i].dma_length) -
+                sgprv = sg;
+        }
+
+        npages = (IO_PAGE_ALIGN(sgprv->dma_address + sgprv->dma_length) -
                   bus_addr) >> IO_PAGE_SHIFT;
 
         base = iommu->page_table +
@@ -730,6 +735,7 @@ static void dma_4u_sync_sg_for_cpu(struct device *dev,
         struct iommu *iommu;
         struct strbuf *strbuf;
         unsigned long flags, ctx, npages, i;
+        struct scatterlist *sg, *sgprv;
         u32 bus_addr;
 
         iommu = dev->archdata.iommu;
@@ -753,11 +759,14 @@ static void dma_4u_sync_sg_for_cpu(struct device *dev,
 
         /* Step 2: Kick data out of streaming buffers. */
         bus_addr = sglist[0].dma_address & IO_PAGE_MASK;
-        for(i = 1; i < nelems; i++)
-                if (!sglist[i].dma_length)
+        sgprv = NULL;
+        for_each_sg(sglist, sg, nelems, i) {
+                if (sg->dma_length == 0)
                         break;
-        i--;
-        npages = (IO_PAGE_ALIGN(sglist[i].dma_address + sglist[i].dma_length)
+                sgprv = sg;
+        }
+
+        npages = (IO_PAGE_ALIGN(sgprv->dma_address + sgprv->dma_length)
                   - bus_addr) >> IO_PAGE_SHIFT;
         strbuf_flush(strbuf, iommu, bus_addr, ctx, npages, direction);
 
diff --git a/arch/sparc64/kernel/pci_sun4v.c b/arch/sparc64/kernel/pci_sun4v.c
index 95de1444ee6..cacacfae545 100644
--- a/arch/sparc64/kernel/pci_sun4v.c
+++ b/arch/sparc64/kernel/pci_sun4v.c
@@ -13,6 +13,7 @@
 #include <linux/irq.h>
 #include <linux/msi.h>
 #include <linux/log2.h>
+#include <linux/scatterlist.h>
 
 #include <asm/iommu.h>
 #include <asm/irq.h>
@@ -373,7 +374,7 @@ static inline long fill_sg(long entry, struct device *dev,
                            int nused, int nelems, unsigned long prot)
 {
         struct scatterlist *dma_sg = sg;
-        struct scatterlist *sg_end = sg + nelems;
+        struct scatterlist *sg_end = sg_last(sg, nelems);
         unsigned long flags;
         int i;
 
@@ -413,7 +414,7 @@ static inline long fill_sg(long entry, struct device *dev,
                                         len -= (IO_PAGE_SIZE - (tmp & (IO_PAGE_SIZE - 1UL)));
                                         break;
                                 }
-                                sg++;
+                                sg = sg_next(sg);
                         }
 
                         pteval = (pteval & IOPTE_PAGE);
@@ -431,24 +432,25 @@ static inline long fill_sg(long entry, struct device *dev,
                         }
 
                         pteval = (pteval & IOPTE_PAGE) + len;
-                        sg++;
+                        sg = sg_next(sg);
 
                         /* Skip over any tail mappings we've fully mapped,
                          * adjusting pteval along the way.  Stop when we
                          * detect a page crossing event.
                          */
-                        while (sg < sg_end &&
-                               (pteval << (64 - IO_PAGE_SHIFT)) != 0UL &&
+                        while ((pteval << (64 - IO_PAGE_SHIFT)) != 0UL &&
                                (pteval == SG_ENT_PHYS_ADDRESS(sg)) &&
                                ((pteval ^
                                  (SG_ENT_PHYS_ADDRESS(sg) + sg->length - 1UL)) >> IO_PAGE_SHIFT) == 0UL) {
                                 pteval += sg->length;
-                                sg++;
+                                if (sg == sg_end)
+                                        break;
+                                sg = sg_next(sg);
                         }
                         if ((pteval << (64 - IO_PAGE_SHIFT)) == 0UL)
                                 pteval = ~0UL;
                 } while (dma_npages != 0);
-                dma_sg++;
+                dma_sg = sg_next(dma_sg);
         }
 
         if (unlikely(iommu_batch_end() < 0L))
@@ -510,7 +512,7 @@ static int dma_4v_map_sg(struct device *dev, struct scatterlist *sglist,
         sgtmp = sglist;
         while (used && sgtmp->dma_length) {
                 sgtmp->dma_address += dma_base;
-                sgtmp++;
+                sgtmp = sg_next(sgtmp);
                 used--;
         }
         used = nelems - used;
@@ -545,6 +547,7 @@ static void dma_4v_unmap_sg(struct device *dev, struct scatterlist *sglist,
         struct pci_pbm_info *pbm;
         struct iommu *iommu;
         unsigned long flags, i, npages;
+        struct scatterlist *sg, *sgprv;
         long entry;
         u32 devhandle, bus_addr;
 
@@ -558,12 +561,15 @@ static void dma_4v_unmap_sg(struct device *dev, struct scatterlist *sglist,
         devhandle = pbm->devhandle;
         
         bus_addr = sglist->dma_address & IO_PAGE_MASK;
-
-        for (i = 1; i < nelems; i++)
-                if (sglist[i].dma_length == 0)
+        sgprv = NULL;
+        for_each_sg(sglist, sg, nelems, i) {
+                if (sg->dma_length == 0)
                         break;
-        i--;
-        npages = (IO_PAGE_ALIGN(sglist[i].dma_address + sglist[i].dma_length) -
+
+                sgprv = sg;
+        }
+
+        npages = (IO_PAGE_ALIGN(sgprv->dma_address + sgprv->dma_length) -
                   bus_addr) >> IO_PAGE_SHIFT;
 
         entry = ((bus_addr - iommu->page_table_map_base) >> IO_PAGE_SHIFT);