PPC: sg chaining support

This updates the ppc iommu/pci dma mappers to sg chaining. Includes
further fixes from FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>.

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

5 files changed, 34 insertions, 165 deletions

diff --git a/arch/powerpc/kernel/dma_64.c b/arch/powerpc/kernel/dma_64.c
index 7b0e754383cf..9001104b56b0 100644
--- a/arch/powerpc/kernel/dma_64.c
+++ b/arch/powerpc/kernel/dma_64.c
@@ -154,12 +154,13 @@ static void dma_direct_unmap_single(struct device *dev, dma_addr_t dma_addr,
 {
 }
 
-static int dma_direct_map_sg(struct device *dev, struct scatterlist *sg,
+static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
                              int nents, enum dma_data_direction direction)
 {
+        struct scatterlist *sg;
         int i;
 
-        for (i = 0; i < nents; i++, sg++) {
+        for_each_sg(sgl, sg, nents, i) {
                 sg->dma_address = (page_to_phys(sg->page) + sg->offset) |
                         dma_direct_offset;
                 sg->dma_length = sg->length;
diff --git a/arch/powerpc/kernel/ibmebus.c b/arch/powerpc/kernel/ibmebus.c
index 53bf64623bd8..2e16ca5778a3 100644
--- a/arch/powerpc/kernel/ibmebus.c
+++ b/arch/powerpc/kernel/ibmebus.c
@@ -87,15 +87,16 @@ static void ibmebus_unmap_single(struct device *dev,
 }
 
 static int ibmebus_map_sg(struct device *dev,
-                          struct scatterlist *sg,
+                          struct scatterlist *sgl,
                           int nents, enum dma_data_direction direction)
 {
+        struct scatterlist *sg;
         int i;
 
-        for (i = 0; i < nents; i++) {
-                sg[i].dma_address = (dma_addr_t)page_address(sg[i].page)
-                        + sg[i].offset;
-                sg[i].dma_length = sg[i].length;
+        for_each_sg(sgl, sg, nents, i) {
+                sg->dma_address = (dma_addr_t)page_address(sg->page)
+                        + sg->offset;
+                sg->dma_length = sg->length;
         }
 
         return nents;
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index e4ec6eee81a8..306a6f75b6c5 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -277,7 +277,7 @@ int iommu_map_sg(struct iommu_table *tbl, struct scatterlist *sglist,
         dma_addr_t dma_next = 0, dma_addr;
         unsigned long flags;
         struct scatterlist *s, *outs, *segstart;
-        int outcount, incount;
+        int outcount, incount, i;
         unsigned long handle;
 
         BUG_ON(direction == DMA_NONE);
@@ -297,7 +297,7 @@ int iommu_map_sg(struct iommu_table *tbl, struct scatterlist *sglist,
 
         spin_lock_irqsave(&(tbl->it_lock), flags);
 
-        for (s = outs; nelems; nelems--, s++) {
+        for_each_sg(sglist, s, nelems, i) {
                 unsigned long vaddr, npages, entry, slen;
 
                 slen = s->length;
@@ -341,7 +341,8 @@ int iommu_map_sg(struct iommu_table *tbl, struct scatterlist *sglist,
                         if (novmerge || (dma_addr != dma_next)) {
                                 /* Can't merge: create a new segment */
                                 segstart = s;
-                                outcount++; outs++;
+                                outcount++;
+                                outs = sg_next(outs);
                                 DBG("    can't merge, new segment.\n");
                         } else {
                                 outs->dma_length += s->length;
@@ -374,7 +375,7 @@ int iommu_map_sg(struct iommu_table *tbl, struct scatterlist *sglist,
          * next entry of the sglist if we didn't fill the list completely
          */
         if (outcount < incount) {
-                outs++;
+                outs = sg_next(outs);
                 outs->dma_address = DMA_ERROR_CODE;
                 outs->dma_length = 0;
         }
@@ -385,7 +386,7 @@ int iommu_map_sg(struct iommu_table *tbl, struct scatterlist *sglist,
         return outcount;
 
  failure:
-        for (s = &sglist[0]; s <= outs; s++) {
+        for_each_sg(sglist, s, nelems, i) {
                 if (s->dma_length != 0) {
                         unsigned long vaddr, npages;
 
@@ -395,6 +396,8 @@ int iommu_map_sg(struct iommu_table *tbl, struct scatterlist *sglist,
                         s->dma_address = DMA_ERROR_CODE;
                         s->dma_length = 0;
                 }
+                if (s == outs)
+                        break;
         }
         spin_unlock_irqrestore(&(tbl->it_lock), flags);
         return 0;
@@ -404,6 +407,7 @@ int iommu_map_sg(struct iommu_table *tbl, struct scatterlist *sglist,
 void iommu_unmap_sg(struct iommu_table *tbl, struct scatterlist *sglist,
                 int nelems, enum dma_data_direction direction)
 {
+        struct scatterlist *sg;
         unsigned long flags;
 
         BUG_ON(direction == DMA_NONE);
@@ -413,15 +417,16 @@ void iommu_unmap_sg(struct iommu_table *tbl, struct scatterlist *sglist,
 
         spin_lock_irqsave(&(tbl->it_lock), flags);
 
+        sg = sglist;
         while (nelems--) {
                 unsigned int npages;
-                dma_addr_t dma_handle = sglist->dma_address;
+                dma_addr_t dma_handle = sg->dma_address;
 
-                if (sglist->dma_length == 0)
+                if (sg->dma_length == 0)
                         break;
-                npages = iommu_num_pages(dma_handle,sglist->dma_length);
+                npages = iommu_num_pages(dma_handle, sg->dma_length);
                 __iommu_free(tbl, dma_handle, npages);
-                sglist++;
+                sg = sg_next(sg);
         }
 
         /* Flush/invalidate TLBs if necessary. As for iommu_free(), we
diff --git a/include/asm-powerpc/dma-mapping.h b/include/asm-powerpc/dma-mapping.h
index 60eacde828c0..2af321f36aba 100644
--- a/include/asm-powerpc/dma-mapping.h
+++ b/include/asm-powerpc/dma-mapping.h
@@ -6,149 +6,6 @@
  */
 #ifndef _ASM_DMA_MAPPING_H
 #define _ASM_DMA_MAPPING_H
-#ifdef __KERNEL__
-
-#include <linux/types.h>
-#include <linux/cache.h>
-/* need struct page definitions */
-#include <linux/mm.h>
-#include <linux/scatterlist.h>
-#include <asm/io.h>
-
-#define DMA_ERROR_CODE          (~(dma_addr_t)0x0)
-
-#ifdef CONFIG_NOT_COHERENT_CACHE
-/*
- * DMA-consistent mapping functions for PowerPCs that don't support
- * cache snooping.  These allocate/free a region of uncached mapped
- * memory space for use with DMA devices.  Alternatively, you could
- * allocate the space "normally" and use the cache management functions
- * to ensure it is consistent.
- */
-extern void *__dma_alloc_coherent(size_t size, dma_addr_t *handle, gfp_t gfp);
-extern void __dma_free_coherent(size_t size, void *vaddr);
-extern void __dma_sync(void *vaddr, size_t size, int direction);
-extern void __dma_sync_page(struct page *page, unsigned long offset,
-                                 size_t size, int direction);
-
-#else /* ! CONFIG_NOT_COHERENT_CACHE */
-/*
- * Cache coherent cores.
- */
-
-#define __dma_alloc_coherent(gfp, size, handle) NULL
-#define __dma_free_coherent(size, addr)         ((void)0)
-#define __dma_sync(addr, size, rw)              ((void)0)
-#define __dma_sync_page(pg, off, sz, rw)        ((void)0)
-
-#endif /* ! CONFIG_NOT_COHERENT_CACHE */
-
-#ifdef CONFIG_PPC64
-/*
- * DMA operations are abstracted for G5 vs. i/pSeries, PCI vs. VIO
- */
-struct dma_mapping_ops {
-        void *          (*alloc_coherent)(struct device *dev, size_t size,
-                                dma_addr_t *dma_handle, gfp_t flag);
-        void            (*free_coherent)(struct device *dev, size_t size,
-                                void *vaddr, dma_addr_t dma_handle);
-        dma_addr_t      (*map_single)(struct device *dev, void *ptr,
-                                size_t size, enum dma_data_direction direction);
-        void            (*unmap_single)(struct device *dev, dma_addr_t dma_addr,
-                                size_t size, enum dma_data_direction direction);
-        int             (*map_sg)(struct device *dev, struct scatterlist *sg,
-                                int nents, enum dma_data_direction direction);
-        void            (*unmap_sg)(struct device *dev, struct scatterlist *sg,
-                                int nents, enum dma_data_direction direction);
-        int             (*dma_supported)(struct device *dev, u64 mask);
-        int             (*set_dma_mask)(struct device *dev, u64 dma_mask);
-};
-
-static inline struct dma_mapping_ops *get_dma_ops(struct device *dev)
-{
-        /* We don't handle the NULL dev case for ISA for now. We could
-         * do it via an out of line call but it is not needed for now. The
-         * only ISA DMA device we support is the floppy and we have a hack
-         * in the floppy driver directly to get a device for us.
-         */
-        if (unlikely(dev == NULL || dev->archdata.dma_ops == NULL))
-                return NULL;
-        return dev->archdata.dma_ops;
-}
-
-static inline int dma_supported(struct device *dev, u64 mask)
-{
-        struct dma_mapping_ops *dma_ops = get_dma_ops(dev);
-
-        if (unlikely(dma_ops == NULL))
-                return 0;
-        if (dma_ops->dma_supported == NULL)
-                return 1;
-        return dma_ops->dma_supported(dev, mask);
-}
-
-static inline int dma_set_mask(struct device *dev, u64 dma_mask)
-{
-        struct dma_mapping_ops *dma_ops = get_dma_ops(dev);
-
-        if (unlikely(dma_ops == NULL))
-                return -EIO;
-        if (dma_ops->set_dma_mask != NULL)
-                return dma_ops->set_dma_mask(dev, dma_mask);
-        if (!dev->dma_mask || !dma_supported(dev, dma_mask))
-                return -EIO;
-        *dev->dma_mask = dma_mask;
-        return 0;
-}
-
-static inline void *dma_alloc_coherent(struct device *dev, size_t size,
-                                       dma_addr_t *dma_handle, gfp_t flag)
-{
-        struct dma_mapping_ops *dma_ops = get_dma_ops(dev);
-
-        BUG_ON(!dma_ops);
-        return dma_ops->alloc_coherent(dev, size, dma_handle, flag);
-}
-
-static inline void dma_free_coherent(struct device *dev, size_t size,
-                                     void *cpu_addr, dma_addr_t dma_handle)
-{
-        struct dma_mapping_ops *dma_ops = get_dma_ops(dev);
-
-        BUG_ON(!dma_ops);
-        dma_ops->free_coherent(dev, size, cpu_addr, dma_handle);
-}
-
-static inline dma_addr_t dma_map_single(struct device *dev, void *cpu_addr,
-                                        size_t size,
-                                        enum dma_data_direction direction)
-{
-        struct dma_mapping_ops *dma_ops = get_dma_ops(dev);
-
-        BUG_ON(!dma_ops);
-        return dma_ops->map_single(dev, cpu_addr, size, direction);
-}
-
-static inline void dma_unmap_single(struct device *dev, dma_addr_t dma_addr,
-                                    size_t size,
-                                    enum dma_data_direction direction)
-{
-        struct dma_mapping_ops *dma_ops = get_dma_ops(dev);
-
-        BUG_ON(!dma_ops);
-        dma_ops->unmap_single(dev, dma_addr, size, direction);
-}
-
-static inline dma_addr_t dma_map_page(struct device *dev, struct page *page,
-                                      unsigned long offset, size_t size,
-                                      enum dma_data_direction direction)
-{
-        struct dma_mapping_ops *dma_ops = get_dma_ops(dev);
-
-        BUG_ON(!dma_ops);
-        return dma_ops->map_single(dev, page_address(page) + offset, size,
-                        direction);
-}
 
 static inline void dma_unmap_page(struct device *dev, dma_addr_t dma_address,
                                   size_t size,
@@ -276,14 +133,15 @@ static inline void dma_unmap_page(struct device *dev, dma_addr_t dma_address,
 }
 
 static inline int
-dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
+dma_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
            enum dma_data_direction direction)
 {
+        struct scatterlist *sg;
         int i;
 
         BUG_ON(direction == DMA_NONE);
 
-        for (i = 0; i < nents; i++, sg++) {
+        for_each_sg(sgl, sg, nents, i) {
                 BUG_ON(!sg->page);
                 __dma_sync_page(sg->page, sg->offset, sg->length, direction);
                 sg->dma_address = page_to_bus(sg->page) + sg->offset;
@@ -318,26 +176,28 @@ static inline void dma_sync_single_for_device(struct device *dev,
 }
 
 static inline void dma_sync_sg_for_cpu(struct device *dev,
-                struct scatterlist *sg, int nents,
+                struct scatterlist *sgl, int nents,
                 enum dma_data_direction direction)
 {
+        struct scatterlist *sg;
         int i;
 
         BUG_ON(direction == DMA_NONE);
 
-        for (i = 0; i < nents; i++, sg++)
+        for_each_sg(sgl, sg, nents, i)
                 __dma_sync_page(sg->page, sg->offset, sg->length, direction);
 }
 
 static inline void dma_sync_sg_for_device(struct device *dev,
-                struct scatterlist *sg, int nents,
+                struct scatterlist *sgl, int nents,
                 enum dma_data_direction direction)
 {
+        struct scatterlist *sg;
         int i;
 
         BUG_ON(direction == DMA_NONE);
 
-        for (i = 0; i < nents; i++, sg++)
+        for_each_sg(sgl, sg, nents, i)
                 __dma_sync_page(sg->page, sg->offset, sg->length, direction);
 }
 
diff --git a/include/asm-powerpc/scatterlist.h b/include/asm-powerpc/scatterlist.h
index 8c992d1491d4..b075f619c3b7 100644
--- a/include/asm-powerpc/scatterlist.h
+++ b/include/asm-powerpc/scatterlist.h
@@ -41,5 +41,7 @@ struct scatterlist {
 #define ISA_DMA_THRESHOLD       (~0UL)
 #endif
 
+#define ARCH_HAS_SG_CHAIN
+
 #endif /* __KERNEL__ */
 #endif /* _ASM_POWERPC_SCATTERLIST_H */