Re: [PATCH 13/22] nds32: use generic dma_noncoherent_ops

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2018-04-20 16:03 GMT+08:00 Christoph Hellwig <hch@xxxxxx>:
Switch to the generic noncoherent direct mapping implementation.

This makes sure kmap_atomic_pfn is consistently used for access to
virtual addresses instead of either using the slower plain kmap
or blindly expecting page_address() to work.

This makes sure the cache_sync routines is called in the unmap_sg
case, to match the unmap_single and sync_{single,sg}_to_cpu cases.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
 arch/nds32/Kconfig                   |   3 +
 arch/nds32/include/asm/Kbuild        |   1 +
 arch/nds32/include/asm/dma-mapping.h |  14 ---
 arch/nds32/kernel/dma.c              | 182 ++++++---------------------
 4 files changed, 39 insertions(+), 161 deletions(-)
 delete mode 100644 arch/nds32/include/asm/dma-mapping.h

diff --git a/arch/nds32/Kconfig b/arch/nds32/Kconfig
index 249f38d3388f..67d0ac0a989c 100644
--- a/arch/nds32/Kconfig
+++ b/arch/nds32/Kconfig
@@ -5,10 +5,13 @@

 config NDS32
         def_bool y
+       select ARCH_HAS_SYNC_DMA_FOR_CPU
+       select ARCH_HAS_SYNC_DMA_FOR_DEVICE
        select ARCH_WANT_FRAME_POINTERS if FTRACE
        select CLKSRC_MMIO
        select CLONE_BACKWARDS
        select COMMON_CLK
+       select DMA_NONCOHERENT_OPS
        select GENERIC_ATOMIC64
        select GENERIC_CPU_DEVICES
        select GENERIC_CLOCKEVENTS
diff --git a/arch/nds32/include/asm/Kbuild b/arch/nds32/include/asm/Kbuild
index 06bdf8167f5a..b3e951f805f8 100644
--- a/arch/nds32/include/asm/Kbuild
+++ b/arch/nds32/include/asm/Kbuild
@@ -13,6 +13,7 @@ generic-y += cputime.h
 generic-y += device.h
 generic-y += div64.h
 generic-y += dma.h
+generic-y += dma-mapping.h
 generic-y += emergency-restart.h
 generic-y += errno.h
 generic-y += exec.h
diff --git a/arch/nds32/include/asm/dma-mapping.h b/arch/nds32/include/asm/dma-mapping.h
deleted file mode 100644
index 2dd47d245c25..000000000000
--- a/arch/nds32/include/asm/dma-mapping.h
+++ /dev/null
@@ -1,14 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-// Copyright (C) 2005-2017 Andes Technology Corporation
-
-#ifndef ASMNDS32_DMA_MAPPING_H
-#define ASMNDS32_DMA_MAPPING_H
-
-extern struct dma_map_ops nds32_dma_ops;
-
-static inline struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus)
-{
-       return &nds32_dma_ops;
-}
-
-#endif
diff --git a/arch/nds32/kernel/dma.c b/arch/nds32/kernel/dma.c
index d291800fc621..688f1a03dee6 100644
--- a/arch/nds32/kernel/dma.c
+++ b/arch/nds32/kernel/dma.c
@@ -3,17 +3,14 @@

 #include <linux/types.h>
 #include <linux/mm.h>
-#include <linux/export.h>
 #include <linux/string.h>
-#include <linux/scatterlist.h>
-#include <linux/dma-mapping.h>
+#include <linux/dma-noncoherent.h>
 #include <linux/io.h>
 #include <linux/cache.h>
 #include <linux/highmem.h>
 #include <linux/slab.h>
 #include <asm/cacheflush.h>
 #include <asm/tlbflush.h>
-#include <asm/dma-mapping.h>
 #include <asm/proc-fns.h>

 /*
@@ -22,11 +19,6 @@
 static pte_t *consistent_pte;
 static DEFINE_RAW_SPINLOCK(consistent_lock);

-enum master_type {
-       FOR_CPU = 0,
-       FOR_DEVICE = 1,
-};
-
 /*
  * VM region handling support.
  *
@@ -124,10 +116,8 @@ static struct arch_vm_region *vm_region_find(struct arch_vm_region *head,
        return c;
 }

-/* FIXME: attrs is not used. */
-static void *nds32_dma_alloc_coherent(struct device *dev, size_t size,
-                                     dma_addr_t * handle, gfp_t gfp,
-                                     unsigned long attrs)
+void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
+               gfp_t gfp, unsigned long attrs)
 {
        struct page *page;
        struct arch_vm_region *c;
@@ -232,8 +222,8 @@ static void *nds32_dma_alloc_coherent(struct device *dev, size_t size,
        return NULL;
 }

-static void nds32_dma_free(struct device *dev, size_t size, void *cpu_addr,
-                          dma_addr_t handle, unsigned long attrs)
+void arch_dma_free(struct device *dev, size_t size, void *cpu_addr,
+               dma_addr_t handle, unsigned long attrs)
 {
        struct arch_vm_region *c;
        unsigned long flags, addr;
@@ -333,145 +323,43 @@ static int __init consistent_init(void)
 }

 core_initcall(consistent_init);
-static void consistent_sync(void *vaddr, size_t size, int direction, int master_type);
-static dma_addr_t nds32_dma_map_page(struct device *dev, struct page *page,
-                                    unsigned long offset, size_t size,
-                                    enum dma_data_direction dir,
-                                    unsigned long attrs)
-{
-       if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
-               consistent_sync((void *)(page_address(page) + offset), size, dir, FOR_DEVICE);
-       return page_to_phys(page) + offset;
-}
-
-static void nds32_dma_unmap_page(struct device *dev, dma_addr_t handle,
-                                size_t size, enum dma_data_direction dir,
-                                unsigned long attrs)
-{
-       if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
-               consistent_sync(phys_to_virt(handle), size, dir, FOR_CPU);
-}

-/*
- * Make an area consistent for devices.
- */
-static void consistent_sync(void *vaddr, size_t size, int direction, int master_type)
+void arch_sync_dma_for_device(struct device *dev, phys_addr_t paddr,
+               size_t size, enum dma_data_direction dir)
 {
-       unsigned long start = (unsigned long)vaddr;
-       unsigned long end = start + size;
-
-       if (master_type == FOR_CPU) {
-               switch (direction) {
-               case DMA_TO_DEVICE:
-                       break;
-               case DMA_FROM_DEVICE:
-               case DMA_BIDIRECTIONAL:
-                       cpu_dma_inval_range(start, end);
-                       break;
-               default:
-                       BUG();
-               }
-       } else {
-               /* FOR_DEVICE */
-               switch (direction) {
-               case DMA_FROM_DEVICE:
-                       break;
-               case DMA_TO_DEVICE:
-               case DMA_BIDIRECTIONAL:
-                       cpu_dma_wb_range(start, end);
-                       break;
-               default:
-                       BUG();
-               }
+       void *addr = kmap_atomic_pfn(PHYS_PFN(paddr));
+       unsigned long start = (unsigned long)addr;
+
+       switch (direction) {
+       case DMA_FROM_DEVICE:
+               break;
+       case DMA_TO_DEVICE:
+       case DMA_BIDIRECTIONAL:
+               cpu_dma_wb_range(start, start + size);
+               break;
+       default:
+               BUG();
        }
-}

-static int nds32_dma_map_sg(struct device *dev, struct scatterlist *sg,
-                           int nents, enum dma_data_direction dir,
-                           unsigned long attrs)
-{
-       int i;
-
-       for (i = 0; i < nents; i++, sg++) {
-               void *virt;
-               unsigned long pfn;
-               struct page *page = sg_page(sg);
-
-               sg->dma_address = sg_phys(sg);
-               pfn = page_to_pfn(page) + sg->offset / PAGE_SIZE;
-               page = pfn_to_page(pfn);
-               if (PageHighMem(page)) {
-                       virt = kmap_atomic(page);
-                       consistent_sync(virt, sg->length, dir, FOR_CPU);
-                       kunmap_atomic(virt);
-               } else {
-                       if (sg->offset > PAGE_SIZE)
-                               panic("sg->offset:%08x > PAGE_SIZE\n",
-                                     sg->offset);
-                       virt = page_address(page) + sg->offset;
-                       consistent_sync(virt, sg->length, dir, FOR_CPU);
-               }
-       }
-       return nents;
-}
-
-static void nds32_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
-                              int nhwentries, enum dma_data_direction dir,
-                              unsigned long attrs)
-{
+       kunmap_atomic(addr);
 }

-static void
-nds32_dma_sync_single_for_cpu(struct device *dev, dma_addr_t handle,
-                             size_t size, enum dma_data_direction dir)
+void arch_sync_dma_for_cpu(struct device *dev, phys_addr_t paddr,
+               size_t size, enum dma_data_direction dir)
 {
-       consistent_sync((void *)phys_to_virt(handle), size, dir, FOR_CPU);
-}
-
-static void
-nds32_dma_sync_single_for_device(struct device *dev, dma_addr_t handle,
-                                size_t size, enum dma_data_direction dir)
-{
-       consistent_sync((void *)phys_to_virt(handle), size, dir, FOR_DEVICE);
-}
-
-static void
-nds32_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg, int nents,
-                         enum dma_data_direction dir)
-{
-       int i;
-
-       for (i = 0; i < nents; i++, sg++) {
-               char *virt =
-                   page_address((struct page *)sg->page_link) + sg->offset;
-               consistent_sync(virt, sg->length, dir, FOR_CPU);
+       void *addr = kmap_atomic_pfn(PHYS_PFN(paddr));
+       unsigned long start = (unsigned long)addr;
+
+       switch (direction) {
+       case DMA_TO_DEVICE:
+               break;
+       case DMA_FROM_DEVICE:
+       case DMA_BIDIRECTIONAL:
+               cpu_dma_inval_range(start, end);
+               break;
+       default:
+               BUG();
        }

  CC      arch/nds32/kernel/dma.o
arch/nds32/kernel/dma.c: In function 'arch_sync_dma_for_device':
arch/nds32/kernel/dma.c:333:10: error: 'direction' undeclared (first
use in this function)
  switch (direction) {
          ^~~~~~~~~
arch/nds32/kernel/dma.c:333:10: note: each undeclared identifier is
reported only once for each function it appears in
arch/nds32/kernel/dma.c: In function 'arch_sync_dma_for_cpu':
arch/nds32/kernel/dma.c:353:10: error: 'direction' undeclared (first
use in this function)
  switch (direction) {
          ^~~~~~~~~
arch/nds32/kernel/dma.c:358:30: error: 'end' undeclared (first use in
this function)
   cpu_dma_inval_range(start, end);
                              ^~~
make[1]: *** [arch/nds32/kernel/dma.o] Error 1
make: *** [arch/nds32/kernel] Error 2

After this building error, the ftmac100.c driver is broken. Not sure
what happened.
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