On Fri, Dec 24, 2010 at 12:20:32AM +0100, Janusz Krzysztofik wrote: > The patch tries to implement a solution suggested by Russell King, > http://lists.infradead.org/pipermail/linux-arm-kernel/2010-December/035264.html. > It is expected to solve video buffer allocation issues for at least a > few soc_camera I/O memory less host interface drivers, designed around > the videobuf_dma_contig layer, which allocates video buffers using > dma_alloc_coherent(). > > Created against linux-2.6.37-rc5. > > Tested on ARM OMAP1 based Amstrad Delta with a WIP OMAP1 camera patch, > patterned upon two mach-mx3 machine types which already try to use the > dma_declare_coherent_memory() method for reserving a region of system > RAM preallocated with another dma_alloc_coherent(). Compile tested for > all modified files except arch/sh/drivers/pci/fixups-dreamcast.c. > > Signed-off-by: Janusz Krzysztofik <jkrzyszt@xxxxxxxxxxxx> > --- > I intended to quote Russell in my commit message and even asked him for > his permission, but since he didn't respond, I decided to include a link > to his original message only. There's no problem quoting messages which were sent to public mailing lists, especially when there's a record of what was said in public archives too. I think this is definitely a step forward. > --- linux-2.6.37-rc5/arch/arm/mach-mx3/mach-pcm037.c.orig 2010-12-09 23:07:34.000000000 +0100 > +++ linux-2.6.37-rc5/arch/arm/mach-mx3/mach-pcm037.c 2010-12-23 18:32:24.000000000 +0100 > @@ -431,7 +431,7 @@ static int __init pcm037_camera_alloc_dm > memset(buf, 0, buf_size); > > dma = dma_declare_coherent_memory(&mx3_camera.dev, > - dma_handle, dma_handle, buf_size, > + buf, dma_handle, buf_size, > DMA_MEMORY_MAP | DMA_MEMORY_EXCLUSIVE); > > /* The way we call dma_declare_coherent_memory only a malloc can fail */ > --- linux-2.6.37-rc5/arch/arm/mach-mx3/mach-mx31moboard.c.orig 2010-12-09 23:07:34.000000000 +0100 > +++ linux-2.6.37-rc5/arch/arm/mach-mx3/mach-mx31moboard.c 2010-12-23 18:32:24.000000000 +0100 > @@ -486,7 +486,7 @@ static int __init mx31moboard_cam_alloc_ > memset(buf, 0, buf_size); > > dma = dma_declare_coherent_memory(&mx3_camera.dev, > - dma_handle, dma_handle, buf_size, > + buf, dma_handle, buf_size, > DMA_MEMORY_MAP | DMA_MEMORY_EXCLUSIVE); > > /* The way we call dma_declare_coherent_memory only a malloc can fail */ A side note for the mx3 folk: although it's not specified in DMA-API, memory allocated from dma_alloc_coherent() on ARM is already memset to zero by the allocation function. > --- linux-2.6.37-rc5/drivers/base/dma-coherent.c.orig 2010-12-09 23:08:03.000000000 +0100 > +++ linux-2.6.37-rc5/drivers/base/dma-coherent.c 2010-12-23 18:32:24.000000000 +0100 > @@ -14,10 +14,9 @@ struct dma_coherent_mem { > unsigned long *bitmap; > }; > > -int dma_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr, > +int dma_declare_coherent_memory(struct device *dev, void *virt_addr, > dma_addr_t device_addr, size_t size, int flags) > { > - void __iomem *mem_base = NULL; > int pages = size >> PAGE_SHIFT; > int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long); > > @@ -30,10 +29,6 @@ int dma_declare_coherent_memory(struct d > > /* FIXME: this routine just ignores DMA_MEMORY_INCLUDES_CHILDREN */ > > - mem_base = ioremap(bus_addr, size); > - if (!mem_base) > - goto out; > - > dev->dma_mem = kzalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL); > if (!dev->dma_mem) > goto out; > @@ -41,7 +36,7 @@ int dma_declare_coherent_memory(struct d > if (!dev->dma_mem->bitmap) > goto free1_out; > > - dev->dma_mem->virt_base = mem_base; > + dev->dma_mem->virt_base = virt_addr; I didn't see anything changing the dev->dma_mem->virt_base type to drop the __iomem attribute (which I suspect shouldn't be there - we're returning it via a void pointer anyway, so I think the whole coherent part of the DMA API should be __iomem-less. It also pushes the sparse address space warnings to the right place IMHO too. -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
