Re: [PATCH 5/9] MIPS: Convert DMA to use dma-mapping-common.h

[David Daney]

On 09/26/2010 10:30 PM, FUJITA Tomonori wrote:
> On Thu, 23 Sep 2010 15:38:12 -0700
> David Daney<ddaney@xxxxxxxxxxxxxxxxxx>  wrote:
>
> > Use asm-generic/dma-mapping-common.h to handle all DMA mapping
> > operations and establish a default get_dma_ops() that forwards all
> > operations to the existing code.
> >
> > Augment dev_archdata to carry a pointer to the struct dma_map_ops,
> > allowing DMA operations to be overridden on a per device basis.
> > Currently this is never filled in, so the default dma_map_ops are
> > used.  A follow-on patch sets this for Octeon PCI devices.
> >
> > Also initialize the dma_debug system as it is now used if it is
> > configured.
> >
> > Signed-off-by: David Daney<ddaney@xxxxxxxxxxxxxxxxxx>
> > ---
> >   arch/mips/Kconfig                   |    2 +
> >   arch/mips/include/asm/device.h      |   15 +++-
> >   arch/mips/include/asm/dma-mapping.h |  125 +++++++++++++++++--------
> >   arch/mips/mm/dma-default.c          |  179 +++++++++++++---------------------
> >   4 files changed, 172 insertions(+), 149 deletions(-)
> >
> > diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
> > index 6c33709..e68b89f 100644
> > --- a/arch/mips/Kconfig
> > +++ b/arch/mips/Kconfig
> > @@ -14,6 +14,8 @@ config MIPS
> >   	select HAVE_KRETPROBES
> >   	select RTC_LIB if !MACH_LOONGSON
> >   	select GENERIC_ATOMIC64 if !64BIT
> > +	select HAVE_DMA_ATTRS
> > +	select HAVE_DMA_API_DEBUG
> >
> >   mainmenu "Linux/MIPS Kernel Configuration"
> >
> > diff --git a/arch/mips/include/asm/device.h b/arch/mips/include/asm/device.h
> > index 06746c5..65bf274 100644
> > --- a/arch/mips/include/asm/device.h
> > +++ b/arch/mips/include/asm/device.h
> > @@ -3,4 +3,17 @@
> >    *
> >    * This file is released under the GPLv2
> >    */
> > -#include<asm-generic/device.h>
> > +#ifndef _ASM_MIPS_DEVICE_H
> > +#define _ASM_MIPS_DEVICE_H
> > +
> > +struct mips_dma_map_ops;
> > +
> > +struct dev_archdata {
> > +	/* DMA operations on that device */
> > +	struct mips_dma_map_ops	*dma_ops;
> > +};
> > +
> > +struct pdev_archdata {
> > +};
> > +
> > +#endif /* _ASM_MIPS_DEVICE_H*/
> > diff --git a/arch/mips/include/asm/dma-mapping.h b/arch/mips/include/asm/dma-mapping.h
> > index 18fbf7a..9a4c307 100644
> > --- a/arch/mips/include/asm/dma-mapping.h
> > +++ b/arch/mips/include/asm/dma-mapping.h
> > @@ -5,51 +5,67 @@
> >   #include<asm/cache.h>
> >   #include<asm-generic/dma-coherent.h>
> >
> > -void *dma_alloc_noncoherent(struct device *dev, size_t size,
> > -			   dma_addr_t *dma_handle, gfp_t flag);
> > +struct mips_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);
> > +};
>
> The above code doesn't look great but we don't want to add phys_to_dma
> and dma_to_phys to dma_map_ops struct, and these functions on MIPS
> looks too complicated for ifdef. So I guess that we need to live with
> the above code.

I think you have a point here.  I will attempt to move these two into a 
chip specific operations vector, and leave the more generic MIPS version 
with the simplified static definition.

Thanks,
David Daney
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