Messages in this thread | | | Date | Tue, 28 Aug 2012 08:53:06 +0530 | Subject | Re: [PATCH 1/2] dw_dmac: make driver endianness configurable | From | Viresh Kumar <> |
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On 27 August 2012 20:28, Hein Tibosch <hein_tibosch@yahoo.es> wrote: >>> +config DW_DMAC_MEM_64_BIT >>> + bool "Allow 64-bit memory transfers" >>> + default y if !AVR32 >>> + depends on DW_DMAC >>> + help >>> + Say yes if the DMA controller may do 64-bit memory transfers >>> + For AVR32, say no because only up to 32-bit transfers are >>> + defined >> Is this sane to add? Could some non-AVR32 platforms use 64-bit and 32-bit >> depending on runtime configuration? E.g. if you build a kernel with support >> for multiple boards/processors, and there is a mix of 32-bit and 64-bit wide >> DMA support. >> >> I think it is better to select 32/64-bit at runtime. > > I did that in the first patch, adding a new property to the dw_dma_slave > structure. It had the small disadvantage that some arch code had to be > adapted (at32ap700x.c). > > Viresh, what do you think? Add a property called "mem_64_bit_access" or so? > > Or should it be passed as a member of 'dw_dma_platform_data', because it > is a property of the (entire) DMA controller?
I think second option is better. But can there be some supportive scenarios of first option?
We have a system, with two different memory controllers, one supporting 32 bit and other 64 bit?
Or what we can do now is: go with option 2, i.e. update dw_dma_platform_data and if some platform like what i mentioned above comes, then we can move it to slave data.
viresh
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