Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
In-Reply-To: <20180420080313.18796-14-hch@lst.de>
References: <20180420080313.18796-1-hch@lst.de> <20180420080313.18796-14-hch@lst.de>
From:   Greentime Hu <green.hu@gmail.com>
Date:   Mon, 23 Apr 2018 14:49:42 +0800
Message-ID: <CAEbi=3fkakVD2vxGu6SgJM77JnNM8Y79xS8_o6m9d_85BJpMFQ@mail.gmail.com>
Subject: Re: [PATCH 13/22] nds32: use generic dma_noncoherent_ops
To:     Christoph Hellwig <hch@lst.de>
Cc:     linux-arch <linux-arch@vger.kernel.org>,
        Michal Simek <monstr@monstr.eu>,
        Vincent Chen <deanbo422@gmail.com>,
        linux-alpha@vger.kernel.org, linux-snps-arc@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org, linux-c6x-dev@linux-c6x.org,
        linux-hexagon@vger.kernel.org, linux-m68k@lists.linux-m68k.org,
        nios2-dev@lists.rocketboards.org, openrisc@lists.librecores.org,
        linux-parisc@vger.kernel.org, linux-sh@vger.kernel.org,
        sparclinux <sparclinux@vger.kernel.org>,
        linux-xtensa@linux-xtensa.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

2018-04-20 16:03 GMT+08:00 Christoph Hellwig <hch@lst.de>:
> 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@lst.de>
> ---
>  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.