Friday 24 December 2010 00:54:34 Russell King - ARM Linux napisaÅ(a): > 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. There was no __iomem attribute specified for the .virt_base member of the struct dma_coherent_mem, pure (void *), so nothing to be changed there. Thanks, Janusz > It also pushes the sparse address space warnings to the right place > IMHO too. > -- > To unsubscribe from this list: send the line "unsubscribe > linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
