On Sun, Dec 15, 2013 at 08:14:32PM +0800, Huacai Chen wrote:
> This is probably a workaround because Loongson doesn't support DMA
> address above 4GB. If memory is more than 4GB, CONFIG_SWIOTLB and
> ZONE_DMA32 should be selected. In this way, DMA pages are allocated
> below 4GB preferably.
>
> However, CONFIG_SWIOTLB+ZONE_DMA32 is not enough, so, we provide a
> platform-specific dma_map_ops::set_dma_mask() to make sure each
> driver's dma_mask and coherent_dma_mask is below 32-bit.
>
> Signed-off-by: Huacai Chen <chenhc@xxxxxxxxxx>
> Signed-off-by: Hongliang Tao <taohl@xxxxxxxxxx>
> Signed-off-by: Hua Yan <yanh@xxxxxxxxxx>
> ---
> arch/mips/include/asm/dma-mapping.h | 5 +
> .../mips/include/asm/mach-loongson/dma-coherence.h | 23 +++
> arch/mips/loongson/common/Makefile | 5 +
> arch/mips/loongson/common/dma-swiotlb.c | 163 ++++++++++++++++++++
> 4 files changed, 196 insertions(+), 0 deletions(-)
> create mode 100644 arch/mips/loongson/common/dma-swiotlb.c
>
> diff --git a/arch/mips/include/asm/dma-mapping.h b/arch/mips/include/asm/dma-mapping.h
> index 84238c5..06412aa 100644
> --- a/arch/mips/include/asm/dma-mapping.h
> +++ b/arch/mips/include/asm/dma-mapping.h
> @@ -49,9 +49,14 @@ static inline int dma_mapping_error(struct device *dev, u64 mask)
> static inline int
> dma_set_mask(struct device *dev, u64 mask)
> {
> + struct dma_map_ops *ops = get_dma_ops(dev);
> +
> if(!dev->dma_mask || !dma_supported(dev, mask))
> return -EIO;
>
> + if (ops->set_dma_mask)
> + return ops->set_dma_mask(dev, mask);
> +
Hmm, this doesn't look correct to me, there is probably a bug somewhere
else... (see below).
> *dev->dma_mask = mask;
>
> return 0;
> diff --git a/arch/mips/include/asm/mach-loongson/dma-coherence.h b/arch/mips/include/asm/mach-loongson/dma-coherence.h
> index aeb2c05..0461161 100644
> --- a/arch/mips/include/asm/mach-loongson/dma-coherence.h
> +++ b/arch/mips/include/asm/mach-loongson/dma-coherence.h
> @@ -11,18 +11,34 @@
> #ifndef __ASM_MACH_LOONGSON_DMA_COHERENCE_H
> #define __ASM_MACH_LOONGSON_DMA_COHERENCE_H
>
> +#ifdef CONFIG_SWIOTLB
> +#include <linux/swiotlb.h>
> +#endif
> +
> struct device;
>
> +extern dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr);
> +extern phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr);
> static inline dma_addr_t plat_map_dma_mem(struct device *dev, void *addr,
> size_t size)
> {
> +#ifdef CONFIG_CPU_LOONGSON3
> + return virt_to_phys(addr) < 0x10000000 ?
> + (virt_to_phys(addr) | 0x0000000080000000) : virt_to_phys(addr);
> +#else
> return virt_to_phys(addr) | 0x80000000;
> +#endif
> }
I have some problem to understand this, especially the fact that the
physical range 0x80000000 -> 0x90000000 will be mapped from two
different area, for virt_to_phys(addr) between 0x00000000 and 0x0fffffff
and for virt_to_phys(addr) between 0x80000000 and 0x90000000.
Could you maybe give us the memory map so that we can understand what is
done here.
> static inline dma_addr_t plat_map_dma_mem_page(struct device *dev,
> struct page *page)
> {
> +#ifdef CONFIG_CPU_LOONGSON3
> + return page_to_phys(page) < 0x10000000 ?
> + (page_to_phys(page) | 0x0000000080000000) : page_to_phys(page);
> +#else
> return page_to_phys(page) | 0x80000000;
> +#endif
> }
Same here.
> static inline unsigned long plat_dma_addr_to_phys(struct device *dev,
> @@ -30,6 +46,9 @@ static inline unsigned long plat_dma_addr_to_phys(struct device *dev,
> {
> #if defined(CONFIG_CPU_LOONGSON2F) && defined(CONFIG_64BIT)
> return (dma_addr > 0x8fffffff) ? dma_addr : (dma_addr & 0x0fffffff);
> +#elif defined(CONFIG_CPU_LOONGSON3) && defined(CONFIG_64BIT)
> + return (dma_addr < 0x90000000 && dma_addr >= 0x80000000) ?
> + (dma_addr & 0x0fffffff) : dma_addr;
> #else
> return dma_addr & 0x7fffffff;
> #endif
> @@ -55,7 +74,11 @@ static inline int plat_dma_supported(struct device *dev, u64 mask)
>
> static inline int plat_device_is_coherent(struct device *dev)
> {
> +#ifdef CONFIG_DMA_NONCOHERENT
> return 0;
> +#else
> + return 1;
> +#endif /* CONFIG_DMA_NONCOHERENT */
> }
>
> #endif /* __ASM_MACH_LOONGSON_DMA_COHERENCE_H */
> diff --git a/arch/mips/loongson/common/Makefile b/arch/mips/loongson/common/Makefile
> index 9e4484c..0bb9cc9 100644
> --- a/arch/mips/loongson/common/Makefile
> +++ b/arch/mips/loongson/common/Makefile
> @@ -26,3 +26,8 @@ obj-$(CONFIG_CS5536) += cs5536/
> #
>
> obj-$(CONFIG_LOONGSON_SUSPEND) += pm.o
> +
> +#
> +# Big Memory (SWIOTLB) Support
> +#
> +obj-$(CONFIG_SWIOTLB) += dma-swiotlb.o
> diff --git a/arch/mips/loongson/common/dma-swiotlb.c b/arch/mips/loongson/common/dma-swiotlb.c
> new file mode 100644
> index 0000000..6741f1b
> --- /dev/null
> +++ b/arch/mips/loongson/common/dma-swiotlb.c
> @@ -0,0 +1,163 @@
> +#include <linux/mm.h>
> +#include <linux/init.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/scatterlist.h>
> +#include <linux/swiotlb.h>
> +#include <linux/bootmem.h>
> +
> +#include <asm/bootinfo.h>
> +#include <dma-coherence.h>
> +
> +static void *loongson_dma_alloc_coherent(struct device *dev, size_t size,
> + dma_addr_t *dma_handle, gfp_t gfp, struct dma_attrs *attrs)
> +{
> + void *ret;
> +
> + if (dma_alloc_from_coherent(dev, size, dma_handle, &ret))
> + return ret;
> +
> + /* ignore region specifiers */
> + gfp &= ~(__GFP_DMA | __GFP_DMA32 | __GFP_HIGHMEM);
> +
> +#ifdef CONFIG_ZONE_DMA
> + if (dev == NULL)
> + gfp |= __GFP_DMA;
> + else if (dev->coherent_dma_mask <= DMA_BIT_MASK(24))
> + gfp |= __GFP_DMA;
> + else
> +#endif
> +#ifdef CONFIG_ZONE_DMA32
> + if (dev == NULL)
> + gfp |= __GFP_DMA32;
> + else if (dev->coherent_dma_mask <= DMA_BIT_MASK(32))
> + gfp |= __GFP_DMA32;
> + else
> +#endif
> + ;
...this part is probably where the bug lies. You have to force
__GFP_DMA32 (unless __GFP_DMA is set), to make sure the DMA will be
allocated in the 32-bit zone, as Loongson 3A doest support DMA only
below 4GB.
Also the logic above is likely wrong, I invite you to look at commit
a2e715a86c6dc85fb4a13c0c818637131de44cd2. You want to use __GFP_DMA if
the dma mask doesn't fit in the 32-bit region.
#ifdef CONFIG_ISA
if (dev == NULL)
dma_flag = __GFP_DMA;
else
#endif
#ifdef CONFIG_ZONE_DMA
if (dev->coherent_dma_mask < DMA_BIT_MASK(32))
dma_flag = __GFP_DMA;
else
#endif
#ifdef CONFIG_ZONE_DMA32
/* Loongson 3A only support DMA in the memory below 4GB */
dma_flag = __GFP_DMA32;
#endif
;
> + gfp |= __GFP_NORETRY;
> +
> + ret = swiotlb_alloc_coherent(dev, size, dma_handle, gfp);
> + mb();
> + return ret;
> +}
> +
> +static void loongson_dma_free_coherent(struct device *dev, size_t size,
> + void *vaddr, dma_addr_t dma_handle, struct dma_attrs *attrs)
> +{
> + int order = get_order(size);
> +
> + if (dma_release_from_coherent(dev, order, vaddr))
> + return;
> +
> + swiotlb_free_coherent(dev, size, vaddr, dma_handle);
> +}
> +
> +static dma_addr_t loongson_dma_map_page(struct device *dev, struct page *page,
> + unsigned long offset, size_t size,
> + enum dma_data_direction dir,
> + struct dma_attrs *attrs)
> +{
> + dma_addr_t daddr = swiotlb_map_page(dev, page, offset, size,
> + dir, attrs);
> + mb();
> + return daddr;
> +}
> +
> +static int loongson_dma_map_sg(struct device *dev, struct scatterlist *sg,
> + int nents, enum dma_data_direction dir,
> + struct dma_attrs *attrs)
> +{
> + int r = swiotlb_map_sg_attrs(dev, sg, nents, dir, NULL);
> + mb();
> +
> + return r;
> +}
> +
> +static void loongson_dma_sync_single_for_device(struct device *dev,
> + dma_addr_t dma_handle, size_t size,
> + enum dma_data_direction dir)
> +{
> + swiotlb_sync_single_for_device(dev, dma_handle, size, dir);
> + mb();
> +}
> +
> +static void loongson_dma_sync_sg_for_device(struct device *dev,
> + struct scatterlist *sg, int nents,
> + enum dma_data_direction dir)
> +{
> + swiotlb_sync_sg_for_device(dev, sg, nents, dir);
> + mb();
> +}
> +
> +static dma_addr_t loongson_unity_phys_to_dma(struct device *dev, phys_addr_t paddr)
> +{
> + return (paddr < 0x10000000) ?
> + (paddr | 0x0000000080000000) : paddr;
> +}
> +
> +static phys_addr_t loongson_unity_dma_to_phys(struct device *dev, dma_addr_t daddr)
> +{
> + return (daddr < 0x90000000 && daddr >= 0x80000000) ?
> + (daddr & 0x0fffffff) : daddr;
> +}
The name "unity" is a big strange here as it's clearly not a transparent
mapping. You should probably just call them loongson_phys_to_dma and
loongson_dma_to_phys. Also as above I don't really understand what is
done here.
> +
> +struct loongson_dma_map_ops {
> + struct dma_map_ops dma_map_ops;
> + dma_addr_t (*phys_to_dma)(struct device *dev, phys_addr_t paddr);
> + phys_addr_t (*dma_to_phys)(struct device *dev, dma_addr_t daddr);
> +};
> +
> +dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
> +{
> + struct loongson_dma_map_ops *ops = container_of(get_dma_ops(dev),
> + struct loongson_dma_map_ops, dma_map_ops);
> +
> + return ops->phys_to_dma(dev, paddr);
> +}
> +
> +phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr)
> +{
> + struct loongson_dma_map_ops *ops = container_of(get_dma_ops(dev),
> + struct loongson_dma_map_ops, dma_map_ops);
> +
> + return ops->dma_to_phys(dev, daddr);
> +}
> +
> +static int loongson_dma_set_mask(struct device *dev, u64 mask)
> +{
> + /* Loongson doesn't support DMA above 32-bit */
> + if (mask > DMA_BIT_MASK(32)) {
> + *dev->dma_mask = DMA_BIT_MASK(32);
> + return -EIO;
> + }
> +
> + *dev->dma_mask = mask;
> +
> + return 0;
> +}
> +
> +static struct loongson_dma_map_ops loongson_linear_dma_map_ops = {
> + .dma_map_ops = {
> + .alloc = loongson_dma_alloc_coherent,
> + .free = loongson_dma_free_coherent,
> + .map_page = loongson_dma_map_page,
> + .unmap_page = swiotlb_unmap_page,
> + .map_sg = loongson_dma_map_sg,
> + .unmap_sg = swiotlb_unmap_sg_attrs,
> + .sync_single_for_cpu = swiotlb_sync_single_for_cpu,
> + .sync_single_for_device = loongson_dma_sync_single_for_device,
> + .sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
> + .sync_sg_for_device = loongson_dma_sync_sg_for_device,
> + .mapping_error = swiotlb_dma_mapping_error,
> + .dma_supported = swiotlb_dma_supported,
> + .set_dma_mask = loongson_dma_set_mask
> + },
> + .phys_to_dma = loongson_unity_phys_to_dma,
> + .dma_to_phys = loongson_unity_dma_to_phys
> +};
> +
> +void __init plat_swiotlb_setup(void)
> +{
> + swiotlb_init(1);
> + mips_dma_map_ops = &loongson_linear_dma_map_ops.dma_map_ops;
> +}
> --
> 1.7.7.3
>
>
>
--
Aurelien Jarno GPG: 1024D/F1BCDB73
aurelien@xxxxxxxxxxx http://www.aurel32.net
