Hi - all
I'm still not work for using DMA API with kernel2.4-ts11 of TS-7400 since last
posted.
Just have something to share and keep some comment.
Now I'm working by compile new kernel with Disable D-CACHE in process of make
menuconfig.
Is'it ok?
Is there someone had experience with make kernel with disable DCACHE?
Any problem hide me for this case?
--- In "pakorn_0608" <> wrote:
>
> Still no good luck for me.
>
> I cannot use "dma_map_single".
> I put it into my code, it can compile, but, when i "insmod" , it have a
> notice "unresolved symbol virt_to_dma" called by dma_map_single.
>
> I search for virt_to_dma and i found that it is at
> {linuxpath}/asm/memory.h:
> #ifndef __arch_page_to_dma
> #define page_to_dma(dev, page)
> ((dma_addr_t)__virt_to_bus(page_address(page)))
> #define dma_to_virt(dev, addr) (__bus_to_virt(addr))
> #define virt_to_dma(dev, addr) (__virt_to_bus(addr))
> #else
> #define page_to_dma(dev, page) (__arch_page_to_dma(dev, page))
> #define dma_to_virt(dev, addr) (__arch_dma_to_virt(dev, addr))
> #define virt_to_dma(dev, addr) (__arch_virt_to_dma(dev, addr))
> #endif
>
>
> I thought It seem like i see virt_to_bus that i use before and it doesn't
> work.
>
> Anyway,i try to include "/asm/memory" to see result of using.It still show
> that "unresolved symbol virt_to_dma" when i insmod my module.
>
>
> --- In "pakorn_0608" <pakorn_0608@> wrote:
> >
> > I just come back on today, back to fight with DMA again.
> >
> > Firstly, your advice book, I found that there is this book at the library
> > of my office. I used to borrow it many for a few month ago when i coding
> > char device driver for linux on ts-7400. I'll borrow it again.
> >
> > Next, for ma_map_single api, i'll check it.
> >
> > Time to solve again.
> >
> > Thanks a lot,BMS.
> >
> > Pakorn
> >
> >
> >
> > --- In "Breton M. Saunders" <breton.saunders@>
> > wrote:
> > >
> > > pakorn_0608 wrote:
> > > > Thanks so much,BMS.
> > > > It's very kind of you.
> > > >
> > > > I'm finding another source of knowledge for solve this problem.
> > > > For "flush_dcache_page" included in "loop.c", It's good guildline for
> > > > me.
> > > > I'll see and learn from it.
> > > >
> > > > If any progress,i'll come to share again.
> > > >
> > > > BTW, I have to go to province on the evening and come back on monday,
> > > > It's hardly to play the net.
> > > > If any message from you,i may have chance to reply on monday.
> > > >
> > > > Thanks in advance.
> > > >
> > > >
> > > Gosh - its been a long time since I've done this stuff.
> > >
> > > Its coming back slowly.
> > >
> > > First thing: check this reference:
> > > http://www.xml.com/ldd/chapter/book/ch13.html
> > > You might just want to buy a copy actually. I found it indispensable
> > > when doing driver development.
> > >
> > > Second, look at:
> > > http://lxr.free-electrons.com/source/Documentation/DMA-API.txt
> > > In particular, section Id on streaming maps. I believe you can just use
> > > the dma_map_single api calls to correctly handle the cache coherency
> > > needed for the M2M.
> > >
> > > Good luck.
> > >
> > > -bms
> > >
> >
>
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