[PATCHv24 14/16] X86: integrate CMA with DMA-mapping subsystem

Marek Szyprowski
2012-04-03T14:12:54Z

This patch adds support for CMA to dma-mapping subsystem for x86
architecture that uses common pci-dma/pci-nommu implementation. This
allows to test CMA on KVM/QEMU and a lot of common x86 boxes.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
CC: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
---
arch/x86/Kconfig | 1 +
arch/x86/include/asm/dma-contiguous.h | 13 +++++++++++++
arch/x86/include/asm/dma-mapping.h | 4 ++++
arch/x86/kernel/pci-dma.c | 18 ++++++++++++++++--
arch/x86/kernel/pci-nommu.c | 8 +-------
arch/x86/kernel/setup.c | 2 ++
6 files changed, 37 insertions(+), 9 deletions(-)
create mode 100644 arch/x86/include/asm/dma-contiguous.h

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 1d14cc6..bc1cfa8 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -31,6 +31,7 @@ config X86
select ARCH_WANT_OPTIONAL_GPIOLIB
select ARCH_WANT_FRAME_POINTERS
select HAVE_DMA_ATTRS
+ select HAVE_DMA_CONTIGUOUS if !SWIOTLB
select HAVE_KRETPROBES
select HAVE_OPTPROBES
select HAVE_FTRACE_MCOUNT_RECORD
diff --git a/arch/x86/include/asm/dma-contiguous.h b/arch/x86/include/asm/dma-contiguous.h
new file mode 100644
index 0000000..c092416
--- /dev/null
+++ b/arch/x86/include/asm/dma-contiguous.h
@@ -0,0 +1,13 @@
+#ifndef ASMX86_DMA_CONTIGUOUS_H
+#define ASMX86_DMA_CONTIGUOUS_H
+
+#ifdef __KERNEL__
+
+#include <linux/types.h>
+#include <asm-generic/dma-contiguous.h>
+
+static inline void
+dma_contiguous_early_fixup(phys_addr_t base, unsigned long size) { }
+
+#endif
+#endif
diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h
index ed3065f..90ac6f0 100644
--- a/arch/x86/include/asm/dma-mapping.h
+++ b/arch/x86/include/asm/dma-mapping.h
@@ -13,6 +13,7 @@
#include <asm/io.h>
#include <asm/swiotlb.h>
#include <asm-generic/dma-coherent.h>
+#include <linux/dma-contiguous.h>

#ifdef CONFIG_ISA
# define ISA_DMA_BIT_MASK DMA_BIT_MASK(24)
@@ -61,6 +62,9 @@ extern int dma_set_mask(struct device *dev, u64 mask);
extern void *dma_generic_alloc_coherent(struct device *dev, size_t size,
dma_addr_t *dma_addr, gfp_t flag);

+extern void dma_generic_free_coherent(struct device *dev, size_t size,
+ void *vaddr, dma_addr_t dma_addr);
+
static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
{
if (!dev->dma_mask)
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index 28e5e06..89094c3 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -99,14 +99,18 @@ void *dma_generic_alloc_coherent(struct device *dev, size_t size,
dma_addr_t *dma_addr, gfp_t flag)
{
unsigned long dma_mask;
- struct page *page;
+ struct page *page = NULL;
+ unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
dma_addr_t addr;

dma_mask = dma_alloc_coherent_mask(dev, flag);

flag |= __GFP_ZERO;
again:
- page = alloc_pages_node(dev_to_node(dev), flag, get_order(size));
+ if (!(flag & GFP_ATOMIC))
+ page = dma_alloc_from_contiguous(dev, count, get_order(size));
+ if (!page)
+ page = alloc_pages_node(dev_to_node(dev), flag, get_order(size));
if (!page)
return NULL;

@@ -126,6 +130,16 @@ again:
return page_address(page);
}

+void dma_generic_free_coherent(struct device *dev, size_t size, void *vaddr,
+ dma_addr_t dma_addr)
+{
+ unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+ struct page *page = virt_to_page(vaddr);
+
+ if (!dma_release_from_contiguous(dev, page, count))
+ free_pages((unsigned long)vaddr, get_order(size));
+}
+
/*
* See <Documentation/x86/x86_64/boot-options.txt> for the iommu kernel
* parameter documentation.
diff --git a/arch/x86/kernel/pci-nommu.c b/arch/x86/kernel/pci-nommu.c
index 3af4af8..656566f 100644
--- a/arch/x86/kernel/pci-nommu.c
+++ b/arch/x86/kernel/pci-nommu.c
@@ -74,12 +74,6 @@ static int nommu_map_sg(struct device *hwdev, struct scatterlist *sg,
return nents;
}

-static void nommu_free_coherent(struct device *dev, size_t size, void *vaddr,
- dma_addr_t dma_addr)
-{
- free_pages((unsigned long)vaddr, get_order(size));
-}
-
static void nommu_sync_single_for_device(struct device *dev,
dma_addr_t addr, size_t size,
enum dma_data_direction dir)
@@ -97,7 +91,7 @@ static void nommu_sync_sg_for_device(struct device *dev,

struct dma_map_ops nommu_dma_ops = {
.alloc_coherent = dma_generic_alloc_coherent,
- .free_coherent = nommu_free_coherent,
+ .free_coherent = dma_generic_free_coherent,
.map_sg = nommu_map_sg,
.map_page = nommu_map_page,
.sync_single_for_device = nommu_sync_single_for_device,
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 1a29015..d6c956e 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -50,6 +50,7 @@
#include <asm/pci-direct.h>
#include <linux/init_ohci1394_dma.h>
#include <linux/kvm_para.h>
+#include <linux/dma-contiguous.h>

#include <linux/errno.h>
#include <linux/kernel.h>
@@ -934,6 +935,7 @@ void __init setup_arch(char **cmdline_p)
}
#endif
memblock.current_limit = get_max_mapped();
+ dma_contiguous_reserve(0);

/*
* NOTE: On x86-32, only from this point on, fixmaps are ready for use.
--
1.7.1.569.g6f426