OpenWrt – Rev 4

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From 2c58080407554e1bac8fd50d23cb02420524caed Mon Sep 17 00:00:00 2001
From: Felix Fietkau <nbd@nbd.name>
Date: Mon, 12 Aug 2013 12:50:22 +0200
Subject: [PATCH] MIPS: partially inline dma ops

Several DMA ops are no-op on many platforms, and the indirection through
the mips_dma_map_ops function table is causing the compiler to emit
unnecessary code.

Inlining visibly improves network performance in my tests (on a 24Kc
based system), and also slightly reduces code size of a few drivers.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
 arch/mips/Kconfig                   |   4 +
 arch/mips/include/asm/dma-mapping.h | 360 +++++++++++++++++++++++++++++++++++-
 arch/mips/mm/dma-default.c          | 163 ++--------------
 3 files changed, 373 insertions(+), 154 deletions(-)

--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -1453,6 +1453,7 @@ config CPU_CAVIUM_OCTEON
        select CPU_SUPPORTS_HUGEPAGES
        select USB_EHCI_BIG_ENDIAN_MMIO
        select MIPS_L1_CACHE_SHIFT_7
+       select SYS_HAS_DMA_OPS
        help
          The Cavium Octeon processor is a highly integrated chip containing
          many ethernet hardware widgets for networking tasks. The processor
@@ -1708,6 +1709,9 @@ config MIPS_MALTA_PM
        bool
        default y
 
+config SYS_HAS_DMA_OPS
+       bool
+
 #
 # CPU may reorder R->R, R->W, W->R, W->W
 # Reordering beyond LL and SC is handled in WEAK_REORDERING_BEYOND_LLSC
--- a/arch/mips/include/asm/dma-mapping.h
+++ b/arch/mips/include/asm/dma-mapping.h
@@ -1,9 +1,16 @@
 #ifndef _ASM_DMA_MAPPING_H
 #define _ASM_DMA_MAPPING_H
 
+#include <linux/kmemcheck.h>
+#include <linux/bug.h>
+#include <linux/scatterlist.h>
+#include <linux/dma-debug.h>
+#include <linux/dma-attrs.h>
+
 #include <asm/scatterlist.h>
 #include <asm/dma-coherence.h>
 #include <asm/cache.h>
+#include <asm/cpu-type.h>
 #include <asm-generic/dma-coherent.h>
 
 #ifndef CONFIG_SGI_IP27 /* Kludge to fix 2.6.39 build for IP27 */
@@ -12,12 +19,48 @@
 
 extern struct dma_map_ops *mips_dma_map_ops;
 
+void __dma_sync(struct page *page, unsigned long offset, size_t size,
+               enum dma_data_direction direction);
+void *mips_dma_alloc_coherent(struct device *dev, size_t size,
+                             dma_addr_t *dma_handle, gfp_t gfp,
+                             struct dma_attrs *attrs);
+void mips_dma_free_coherent(struct device *dev, size_t size, void *vaddr,
+                           dma_addr_t dma_handle, struct dma_attrs *attrs);
+
 static inline struct dma_map_ops *get_dma_ops(struct device *dev)
 {
+#ifdef CONFIG_SYS_HAS_DMA_OPS
        if (dev && dev->archdata.dma_ops)
                return dev->archdata.dma_ops;
        else
                return mips_dma_map_ops;
+#else
+       return NULL;
+#endif
+}
+
+/*
+ * Warning on the terminology - Linux calls an uncached area coherent;
+ * MIPS terminology calls memory areas with hardware maintained coherency
+ * coherent.
+ */
+
+static inline int cpu_needs_post_dma_flush(struct device *dev)
+{
+#ifndef CONFIG_SYS_HAS_CPU_R10000
+       return 0;
+#endif
+       return !plat_device_is_coherent(dev) &&
+              (boot_cpu_type() == CPU_R10000 ||
+               boot_cpu_type() == CPU_R12000 ||
+               boot_cpu_type() == CPU_BMIPS5000);
+}
+
+static inline struct page *dma_addr_to_page(struct device *dev,
+       dma_addr_t dma_addr)
+{
+       return pfn_to_page(
+               plat_dma_addr_to_phys(dev, dma_addr) >> PAGE_SHIFT);
 }
 
 static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
@@ -30,12 +73,304 @@ static inline bool dma_capable(struct de
 
 static inline void dma_mark_clean(void *addr, size_t size) {}
 
-#include <asm-generic/dma-mapping-common.h>
+static inline dma_addr_t dma_map_single_attrs(struct device *dev, void *ptr,
+                                             size_t size,
+                                             enum dma_data_direction dir,
+                                             struct dma_attrs *attrs)
+{
+       struct dma_map_ops *ops = get_dma_ops(dev);
+       unsigned long offset = (unsigned long)ptr & ~PAGE_MASK;
+       struct page *page = virt_to_page(ptr);
+       dma_addr_t addr;
+
+       kmemcheck_mark_initialized(ptr, size);
+       BUG_ON(!valid_dma_direction(dir));
+       if (ops) {
+               addr = ops->map_page(dev, page, offset, size, dir, attrs);
+       } else {
+               if (!plat_device_is_coherent(dev))
+                       __dma_sync(page, offset, size, dir);
+
+               addr = plat_map_dma_mem_page(dev, page) + offset;
+       }
+       debug_dma_map_page(dev, page, offset, size, dir, addr, true);
+       return addr;
+}
+
+static inline void dma_unmap_single_attrs(struct device *dev, dma_addr_t addr,
+                                         size_t size,
+                                         enum dma_data_direction dir,
+                                         struct dma_attrs *attrs)
+{
+       struct dma_map_ops *ops = get_dma_ops(dev);
+
+       BUG_ON(!valid_dma_direction(dir));
+       if (ops) {
+               ops->unmap_page(dev, addr, size, dir, attrs);
+       } else {
+               if (cpu_needs_post_dma_flush(dev))
+                       __dma_sync(dma_addr_to_page(dev, addr),
+                                  addr & ~PAGE_MASK, size, dir);
+
+               plat_unmap_dma_mem(dev, addr, size, dir);
+       }
+       debug_dma_unmap_page(dev, addr, size, dir, true);
+}
+
+static inline int dma_map_sg_attrs(struct device *dev, struct scatterlist *sg,
+                                  int nents, enum dma_data_direction dir,
+                                  struct dma_attrs *attrs)
+{
+       struct dma_map_ops *ops = get_dma_ops(dev);
+       int i, ents;
+       struct scatterlist *s;
+
+       for_each_sg(sg, s, nents, i)
+               kmemcheck_mark_initialized(sg_virt(s), s->length);
+       BUG_ON(!valid_dma_direction(dir));
+       if (ops) {
+               ents = ops->map_sg(dev, sg, nents, dir, attrs);
+       } else {
+               for_each_sg(sg, s, nents, i) {
+                       struct page *page = sg_page(s);
+
+                       if (!plat_device_is_coherent(dev))
+                               __dma_sync(page, s->offset, s->length, dir);
+#ifdef CONFIG_NEED_SG_DMA_LENGTH
+                       s->dma_length = s->length;
+#endif
+                       s->dma_address =
+                               plat_map_dma_mem_page(dev, page) + s->offset;
+               }
+               ents = nents;
+       }
+       debug_dma_map_sg(dev, sg, nents, ents, dir);
+
+       return ents;
+}
+
+static inline void dma_unmap_sg_attrs(struct device *dev, struct scatterlist *sg,
+                                     int nents, enum dma_data_direction dir,
+                                     struct dma_attrs *attrs)
+{
+       struct dma_map_ops *ops = get_dma_ops(dev);
+       struct scatterlist *s;
+       int i;
+
+       BUG_ON(!valid_dma_direction(dir));
+       debug_dma_unmap_sg(dev, sg, nents, dir);
+       if (ops) {
+               ops->unmap_sg(dev, sg, nents, dir, attrs);
+               return;
+       }
+
+       for_each_sg(sg, s, nents, i) {
+               if (!plat_device_is_coherent(dev) && dir != DMA_TO_DEVICE)
+                       __dma_sync(sg_page(s), s->offset, s->length, dir);
+               plat_unmap_dma_mem(dev, s->dma_address, s->length, dir);
+       }
+}
+
+static inline dma_addr_t dma_map_page(struct device *dev, struct page *page,
+                                     size_t offset, size_t size,
+                                     enum dma_data_direction dir)
+{
+       struct dma_map_ops *ops = get_dma_ops(dev);
+       dma_addr_t addr;
+
+       kmemcheck_mark_initialized(page_address(page) + offset, size);
+       BUG_ON(!valid_dma_direction(dir));
+       if (ops) {
+               addr = ops->map_page(dev, page, offset, size, dir, NULL);
+       } else {
+               if (!plat_device_is_coherent(dev))
+                       __dma_sync(page, offset, size, dir);
+
+               addr = plat_map_dma_mem_page(dev, page) + offset;
+       }
+       debug_dma_map_page(dev, page, offset, size, dir, addr, false);
+
+       return addr;
+}
+
+static inline void dma_unmap_page(struct device *dev, dma_addr_t addr,
+                                 size_t size, enum dma_data_direction dir)
+{
+       struct dma_map_ops *ops = get_dma_ops(dev);
+
+       BUG_ON(!valid_dma_direction(dir));
+       if (ops) {
+               ops->unmap_page(dev, addr, size, dir, NULL);
+       } else {
+               if (cpu_needs_post_dma_flush(dev))
+                       __dma_sync(dma_addr_to_page(dev, addr),
+                                  addr & ~PAGE_MASK, size, dir);
+
+               plat_unmap_dma_mem(dev, addr, size, dir);
+       }
+       debug_dma_unmap_page(dev, addr, size, dir, false);
+}
+
+static inline void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr,
+                                          size_t size,
+                                          enum dma_data_direction dir)
+{
+       struct dma_map_ops *ops = get_dma_ops(dev);
+
+       BUG_ON(!valid_dma_direction(dir));
+       if (ops)
+               ops->sync_single_for_cpu(dev, addr, size, dir);
+       else if (cpu_needs_post_dma_flush(dev))
+               __dma_sync(dma_addr_to_page(dev, addr),
+                          addr & ~PAGE_MASK, size, dir);
+       debug_dma_sync_single_for_cpu(dev, addr, size, dir);
+}
+
+static inline void dma_sync_single_for_device(struct device *dev,
+                                             dma_addr_t addr, size_t size,
+                                             enum dma_data_direction dir)
+{
+       struct dma_map_ops *ops = get_dma_ops(dev);
+
+       BUG_ON(!valid_dma_direction(dir));
+       if (ops)
+               ops->sync_single_for_device(dev, addr, size, dir);
+       else if (!plat_device_is_coherent(dev))
+               __dma_sync(dma_addr_to_page(dev, addr),
+                          addr & ~PAGE_MASK, size, dir);
+       debug_dma_sync_single_for_device(dev, addr, size, dir);
+}
+
+static inline void dma_sync_single_range_for_cpu(struct device *dev,
+                                                dma_addr_t addr,
+                                                unsigned long offset,
+                                                size_t size,
+                                                enum dma_data_direction dir)
+{
+       const struct dma_map_ops *ops = get_dma_ops(dev);
+
+       BUG_ON(!valid_dma_direction(dir));
+       if (ops)
+               ops->sync_single_for_cpu(dev, addr + offset, size, dir);
+       else if (cpu_needs_post_dma_flush(dev))
+               __dma_sync(dma_addr_to_page(dev, addr + offset),
+                          (addr + offset) & ~PAGE_MASK, size, dir);
+       debug_dma_sync_single_range_for_cpu(dev, addr, offset, size, dir);
+}
+
+static inline void dma_sync_single_range_for_device(struct device *dev,
+                                                   dma_addr_t addr,
+                                                   unsigned long offset,
+                                                   size_t size,
+                                                   enum dma_data_direction dir)
+{
+       const struct dma_map_ops *ops = get_dma_ops(dev);
+
+       BUG_ON(!valid_dma_direction(dir));
+       if (ops)
+               ops->sync_single_for_device(dev, addr + offset, size, dir);
+       else if (!plat_device_is_coherent(dev))
+               __dma_sync(dma_addr_to_page(dev, addr + offset),
+                          (addr + offset) & ~PAGE_MASK, size, dir);
+       debug_dma_sync_single_range_for_device(dev, addr, offset, size, dir);
+}
+
+static inline void
+dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
+                   int nelems, enum dma_data_direction dir)
+{
+       struct dma_map_ops *ops = get_dma_ops(dev);
+       struct scatterlist *s;
+       int i;
+
+       BUG_ON(!valid_dma_direction(dir));
+       if (ops)
+               ops->sync_sg_for_cpu(dev, sg, nelems, dir);
+       else if (cpu_needs_post_dma_flush(dev)) {
+               for_each_sg(sg, s, nelems, i)
+                       __dma_sync(sg_page(s), s->offset, s->length, dir);
+       }
+       debug_dma_sync_sg_for_cpu(dev, sg, nelems, dir);
+}
+
+static inline void
+dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
+                      int nelems, enum dma_data_direction dir)
+{
+       struct dma_map_ops *ops = get_dma_ops(dev);
+       struct scatterlist *s;
+       int i;
+
+       BUG_ON(!valid_dma_direction(dir));
+       if (ops)
+               ops->sync_sg_for_device(dev, sg, nelems, dir);
+       else if (!plat_device_is_coherent(dev)) {
+               for_each_sg(sg, s, nelems, i)
+                       __dma_sync(sg_page(s), s->offset, s->length, dir);
+       }
+       debug_dma_sync_sg_for_device(dev, sg, nelems, dir);
+
+}
+
+#define dma_map_single(d, a, s, r) dma_map_single_attrs(d, a, s, r, NULL)
+#define dma_unmap_single(d, a, s, r) dma_unmap_single_attrs(d, a, s, r, NULL)
+#define dma_map_sg(d, s, n, r) dma_map_sg_attrs(d, s, n, r, NULL)
+#define dma_unmap_sg(d, s, n, r) dma_unmap_sg_attrs(d, s, n, r, NULL)
+
+extern int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
+                          void *cpu_addr, dma_addr_t dma_addr, size_t size);
+
+/**
+ * dma_mmap_attrs - map a coherent DMA allocation into user space
+ * @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
+ * @vma: vm_area_struct describing requested user mapping
+ * @cpu_addr: kernel CPU-view address returned from dma_alloc_attrs
+ * @handle: device-view address returned from dma_alloc_attrs
+ * @size: size of memory originally requested in dma_alloc_attrs
+ * @attrs: attributes of mapping properties requested in dma_alloc_attrs
+ *
+ * Map a coherent DMA buffer previously allocated by dma_alloc_attrs
+ * into user space.  The coherent DMA buffer must not be freed by the
+ * driver until the user space mapping has been released.
+ */
+static inline int
+dma_mmap_attrs(struct device *dev, struct vm_area_struct *vma, void *cpu_addr,
+              dma_addr_t dma_addr, size_t size, struct dma_attrs *attrs)
+{
+       struct dma_map_ops *ops = get_dma_ops(dev);
+       BUG_ON(!ops);
+       if (ops && ops->mmap)
+               return ops->mmap(dev, vma, cpu_addr, dma_addr, size, attrs);
+       return dma_common_mmap(dev, vma, cpu_addr, dma_addr, size);
+}
+
+#define dma_mmap_coherent(d, v, c, h, s) dma_mmap_attrs(d, v, c, h, s, NULL)
+
+int
+dma_common_get_sgtable(struct device *dev, struct sg_table *sgt,
+                      void *cpu_addr, dma_addr_t dma_addr, size_t size);
+
+static inline int
+dma_get_sgtable_attrs(struct device *dev, struct sg_table *sgt, void *cpu_addr,
+                     dma_addr_t dma_addr, size_t size, struct dma_attrs *attrs)
+{
+       struct dma_map_ops *ops = get_dma_ops(dev);
+       BUG_ON(!ops);
+       if (ops && ops->get_sgtable)
+               return ops->get_sgtable(dev, sgt, cpu_addr, dma_addr, size,
+                                       attrs);
+       return dma_common_get_sgtable(dev, sgt, cpu_addr, dma_addr, size);
+}
+
+#define dma_get_sgtable(d, t, v, h, s) dma_get_sgtable_attrs(d, t, v, h, s, NULL)
+
 
 static inline int dma_supported(struct device *dev, u64 mask)
 {
        struct dma_map_ops *ops = get_dma_ops(dev);
-       return ops->dma_supported(dev, mask);
+       if (ops)
+               return ops->dma_supported(dev, mask);
+       return plat_dma_supported(dev, mask);
 }
 
 static inline int dma_mapping_error(struct device *dev, u64 mask)
@@ -43,7 +378,9 @@ static inline int dma_mapping_error(stru
        struct dma_map_ops *ops = get_dma_ops(dev);
 
        debug_dma_mapping_error(dev, mask);
-       return ops->mapping_error(dev, mask);
+       if (ops)
+               return ops->mapping_error(dev, mask);
+       return 0;
 }
 
 static inline int
@@ -54,7 +391,7 @@ dma_set_mask(struct device *dev, u64 mas
        if(!dev->dma_mask || !dma_supported(dev, mask))
                return -EIO;
 
-       if (ops->set_dma_mask)
+       if (ops && ops->set_dma_mask)
                return ops->set_dma_mask(dev, mask);
 
        *dev->dma_mask = mask;
@@ -74,7 +411,11 @@ static inline void *dma_alloc_attrs(stru
        void *ret;
        struct dma_map_ops *ops = get_dma_ops(dev);
 
-       ret = ops->alloc(dev, size, dma_handle, gfp, attrs);
+       if (ops)
+               ret = ops->alloc(dev, size, dma_handle, gfp, attrs);
+       else
+               ret = mips_dma_alloc_coherent(dev, size, dma_handle, gfp,
+                                             attrs);
 
        debug_dma_alloc_coherent(dev, size, *dma_handle, ret);
 
@@ -89,7 +430,10 @@ static inline void dma_free_attrs(struct
 {
        struct dma_map_ops *ops = get_dma_ops(dev);
 
-       ops->free(dev, size, vaddr, dma_handle, attrs);
+       if (ops)
+               ops->free(dev, size, vaddr, dma_handle, attrs);
+       else
+               mips_dma_free_coherent(dev, size, vaddr, dma_handle, attrs);
 
        debug_dma_free_coherent(dev, size, vaddr, dma_handle);
 }
--- a/arch/mips/mm/dma-default.c
+++ b/arch/mips/mm/dma-default.c
@@ -26,7 +26,7 @@
 
 #ifdef CONFIG_DMA_MAYBE_COHERENT
 int coherentio = 0;    /* User defined DMA coherency from command line. */
-EXPORT_SYMBOL_GPL(coherentio);
+EXPORT_SYMBOL(coherentio);
 int hw_coherentio = 0; /* Actual hardware supported DMA coherency setting. */
 
 static int __init setcoherentio(char *str)
@@ -46,30 +46,6 @@ static int __init setnocoherentio(char *
 early_param("nocoherentio", setnocoherentio);
 #endif
 
-static inline struct page *dma_addr_to_page(struct device *dev,
-       dma_addr_t dma_addr)
-{
-       return pfn_to_page(
-               plat_dma_addr_to_phys(dev, dma_addr) >> PAGE_SHIFT);
-}
-
-/*
- * The affected CPUs below in 'cpu_needs_post_dma_flush()' can
- * speculatively fill random cachelines with stale data at any time,
- * requiring an extra flush post-DMA.
- *
- * Warning on the terminology - Linux calls an uncached area coherent;
- * MIPS terminology calls memory areas with hardware maintained coherency
- * coherent.
- */
-static inline int cpu_needs_post_dma_flush(struct device *dev)
-{
-       return !plat_device_is_coherent(dev) &&
-              (boot_cpu_type() == CPU_R10000 ||
-               boot_cpu_type() == CPU_R12000 ||
-               boot_cpu_type() == CPU_BMIPS5000);
-}
-
 static gfp_t massage_gfp_flags(const struct device *dev, gfp_t gfp)
 {
        gfp_t dma_flag;
@@ -125,8 +101,9 @@ void *dma_alloc_noncoherent(struct devic
 }
 EXPORT_SYMBOL(dma_alloc_noncoherent);
 
-static void *mips_dma_alloc_coherent(struct device *dev, size_t size,
-       dma_addr_t * dma_handle, gfp_t gfp, struct dma_attrs *attrs)
+void *mips_dma_alloc_coherent(struct device *dev, size_t size,
+                             dma_addr_t *dma_handle, gfp_t gfp,
+                             struct dma_attrs *attrs)
 {
        void *ret;
        struct page *page = NULL;
@@ -157,6 +134,7 @@ static void *mips_dma_alloc_coherent(str
 
        return ret;
 }
+EXPORT_SYMBOL(mips_dma_alloc_coherent);
 
 
 void dma_free_noncoherent(struct device *dev, size_t size, void *vaddr,
@@ -167,8 +145,8 @@ void dma_free_noncoherent(struct device
 }
 EXPORT_SYMBOL(dma_free_noncoherent);
 
-static void mips_dma_free_coherent(struct device *dev, size_t size, void *vaddr,
-       dma_addr_t dma_handle, struct dma_attrs *attrs)
+void mips_dma_free_coherent(struct device *dev, size_t size, void *vaddr,
+                           dma_addr_t dma_handle, struct dma_attrs *attrs)
 {
        unsigned long addr = (unsigned long) vaddr;
        int order = get_order(size);
@@ -188,6 +166,7 @@ static void mips_dma_free_coherent(struc
        if (!dma_release_from_contiguous(dev, page, count))
                __free_pages(page, get_order(size));
 }
+EXPORT_SYMBOL(mips_dma_free_coherent);
 
 static inline void __dma_sync_virtual(void *addr, size_t size,
        enum dma_data_direction direction)
@@ -216,8 +195,8 @@ static inline void __dma_sync_virtual(vo
  * If highmem is not configured then the bulk of this loop gets
  * optimized out.
  */
-static inline void __dma_sync(struct page *page,
-       unsigned long offset, size_t size, enum dma_data_direction direction)
+void __dma_sync(struct page *page, unsigned long offset, size_t size,
+               enum dma_data_direction direction)
 {
        size_t left = size;
 
@@ -246,108 +225,7 @@ static inline void __dma_sync(struct pag
                left -= len;
        } while (left);
 }
-
-static void mips_dma_unmap_page(struct device *dev, dma_addr_t dma_addr,
-       size_t size, enum dma_data_direction direction, struct dma_attrs *attrs)
-{
-       if (cpu_needs_post_dma_flush(dev))
-               __dma_sync(dma_addr_to_page(dev, dma_addr),
-                          dma_addr & ~PAGE_MASK, size, direction);
-
-       plat_unmap_dma_mem(dev, dma_addr, size, direction);
-}
-
-static int mips_dma_map_sg(struct device *dev, struct scatterlist *sg,
-       int nents, enum dma_data_direction direction, struct dma_attrs *attrs)
-{
-       int i;
-
-       for (i = 0; i < nents; i++, sg++) {
-               if (!plat_device_is_coherent(dev))
-                       __dma_sync(sg_page(sg), sg->offset, sg->length,
-                                  direction);
-#ifdef CONFIG_NEED_SG_DMA_LENGTH
-               sg->dma_length = sg->length;
-#endif
-               sg->dma_address = plat_map_dma_mem_page(dev, sg_page(sg)) +
-                                 sg->offset;
-       }
-
-       return nents;
-}
-
-static dma_addr_t mips_dma_map_page(struct device *dev, struct page *page,
-       unsigned long offset, size_t size, enum dma_data_direction direction,
-       struct dma_attrs *attrs)
-{
-       if (!plat_device_is_coherent(dev))
-               __dma_sync(page, offset, size, direction);
-
-       return plat_map_dma_mem_page(dev, page) + offset;
-}
-
-static void mips_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
-       int nhwentries, enum dma_data_direction direction,
-       struct dma_attrs *attrs)
-{
-       int i;
-
-       for (i = 0; i < nhwentries; i++, sg++) {
-               if (!plat_device_is_coherent(dev) &&
-                   direction != DMA_TO_DEVICE)
-                       __dma_sync(sg_page(sg), sg->offset, sg->length,
-                                  direction);
-               plat_unmap_dma_mem(dev, sg->dma_address, sg->length, direction);
-       }
-}
-
-static void mips_dma_sync_single_for_cpu(struct device *dev,
-       dma_addr_t dma_handle, size_t size, enum dma_data_direction direction)
-{
-       if (cpu_needs_post_dma_flush(dev))
-               __dma_sync(dma_addr_to_page(dev, dma_handle),
-                          dma_handle & ~PAGE_MASK, size, direction);
-}
-
-static void mips_dma_sync_single_for_device(struct device *dev,
-       dma_addr_t dma_handle, size_t size, enum dma_data_direction direction)
-{
-       if (!plat_device_is_coherent(dev))
-               __dma_sync(dma_addr_to_page(dev, dma_handle),
-                          dma_handle & ~PAGE_MASK, size, direction);
-}
-
-static void mips_dma_sync_sg_for_cpu(struct device *dev,
-       struct scatterlist *sg, int nelems, enum dma_data_direction direction)
-{
-       int i;
-
-       if (cpu_needs_post_dma_flush(dev))
-               for (i = 0; i < nelems; i++, sg++)
-                       __dma_sync(sg_page(sg), sg->offset, sg->length,
-                                  direction);
-}
-
-static void mips_dma_sync_sg_for_device(struct device *dev,
-       struct scatterlist *sg, int nelems, enum dma_data_direction direction)
-{
-       int i;
-
-       if (!plat_device_is_coherent(dev))
-               for (i = 0; i < nelems; i++, sg++)
-                       __dma_sync(sg_page(sg), sg->offset, sg->length,
-                                  direction);
-}
-
-int mips_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
-{
-       return 0;
-}
-
-int mips_dma_supported(struct device *dev, u64 mask)
-{
-       return plat_dma_supported(dev, mask);
-}
+EXPORT_SYMBOL(__dma_sync);
 
 void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
                         enum dma_data_direction direction)
@@ -360,23 +238,10 @@ void dma_cache_sync(struct device *dev,
 
 EXPORT_SYMBOL(dma_cache_sync);
 
-static struct dma_map_ops mips_default_dma_map_ops = {
-       .alloc = mips_dma_alloc_coherent,
-       .free = mips_dma_free_coherent,
-       .map_page = mips_dma_map_page,
-       .unmap_page = mips_dma_unmap_page,
-       .map_sg = mips_dma_map_sg,
-       .unmap_sg = mips_dma_unmap_sg,
-       .sync_single_for_cpu = mips_dma_sync_single_for_cpu,
-       .sync_single_for_device = mips_dma_sync_single_for_device,
-       .sync_sg_for_cpu = mips_dma_sync_sg_for_cpu,
-       .sync_sg_for_device = mips_dma_sync_sg_for_device,
-       .mapping_error = mips_dma_mapping_error,
-       .dma_supported = mips_dma_supported
-};
-
-struct dma_map_ops *mips_dma_map_ops = &mips_default_dma_map_ops;
+#ifdef CONFIG_SYS_HAS_DMA_OPS
+struct dma_map_ops *mips_dma_map_ops = NULL;
 EXPORT_SYMBOL(mips_dma_map_ops);
+#endif
 
 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)