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

Christoph Hellwig
2018-04-25T06:39:28Z

On Wed, Apr 25, 2018 at 09:43:43AM +0800, Greentime Hu wrote:
> Hi Crhistoph,
>
> The ftmac100 works if I revert this commit.

Thanks. ftmac100 only use dma_map_page, which in the old nds32 code
is just doing a plain page_address and never kmaps. Can you apply
the patch below on the tree with the origin "nds32: use generic
dma_noncoherent_ops" reverted? This always just uses page_address,
although that, just like the original code is broken if you actually
have highmem that needs to be mapped:

---
>From 1dc5d1cae4cd7b9ce03d0e2943364ed4cca938d7 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Mon, 16 Apr 2018 19:20:30 +0200
Subject: nds32: use generic dma_noncoherent_ops

Switch to the generic noncoherent direct mapping implementation.

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, 37 insertions(+), 163 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..78311a1e6fd1 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 +323,39 @@ 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)
+void arch_sync_dma_for_device(struct device *dev, phys_addr_t paddr,
+ size_t size, enum dma_data_direction dir)
{
- 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)
-{
- 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 = phys_to_virt(paddr);
+ unsigned long start = (unsigned long)addr;
+
+ switch (dir) {
+ 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)
+void arch_sync_dma_for_cpu(struct device *dev, phys_addr_t paddr,
+ size_t size, enum dma_data_direction dir)
{
- 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);
- }
+ void *addr = phys_to_virt(paddr);
+ unsigned long start = (unsigned long)addr;
+
+ switch (dir) {
+ case DMA_TO_DEVICE:
+ break;
+ case DMA_FROM_DEVICE:
+ case DMA_BIDIRECTIONAL:
+ cpu_dma_inval_range(start, start + size);
+ break;
+ default:
+ BUG();
}
- return nents;
}
-
-static void nds32_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
- int nhwentries, enum dma_data_direction dir,
- unsigned long attrs)
-{
-}
-
-static void
-nds32_dma_sync_single_for_cpu(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_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);
- }
-}
-
-static void
-nds32_dma_sync_sg_for_device(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_DEVICE);
- }
-}
-
-struct dma_map_ops nds32_dma_ops = {
- .alloc = nds32_dma_alloc_coherent,
- .free = nds32_dma_free,
- .map_page = nds32_dma_map_page,
- .unmap_page = nds32_dma_unmap_page,
- .map_sg = nds32_dma_map_sg,
- .unmap_sg = nds32_dma_unmap_sg,
- .sync_single_for_device = nds32_dma_sync_single_for_device,
- .sync_single_for_cpu = nds32_dma_sync_single_for_cpu,
- .sync_sg_for_cpu = nds32_dma_sync_sg_for_cpu,
- .sync_sg_for_device = nds32_dma_sync_sg_for_device,
-};
-
-EXPORT_SYMBOL(nds32_dma_ops);
--
2.17.0