Hi everyone
there is a problem of my own driver
I want to get data from kernel space to user space indirectly using mmap()
but i dont know how I can do , anyone can give me some advices ?
firstly, fetch data by DMA to a memory allocated by "kmalloc"
then i want to mmap it to user space and save
>
> in the manual reference charpter 9.13 DMA, source and destination address
> If you are DMAing from an internal peripheral, then it's
> width will be hard-coded and can be read from the user-manual.
you mean it will be set by hard circuit ? maybe i should talk with your hard
engineer.
but as
thank you dave for your reply
my processor is MPC8247, on Linux 2.6.11
in MPC8247 manual reference, the interrupt of DMA unit belonged PCI bridge.
that is different from SDMA and IDMA. through i do not know what 's the
different. heard SDMA is used to transfer between CPM and 60x. DMA is used
excuse me
I hate to bother everyone but I have a question about DMA of PCI bridge
Now I attempt to fetch data from peripheral device to SDRAM, and it has been
successed
but how the DMA controller know the data bandwidth of src and dest.
for example, if i get a 16bits data with a 32bits bus, and
i tried to fetch data from periphial memories with DMA
the flow as following
flags = claim_dma_lock();
disable_dma(DMA_CH);
clear_dma_ff();
set_dma_count(DMA_CH, 4);
set_dma_addr(DMA_CH, virt_to_bus(kv_buf));
release_dma_lock(flags);
enable_dma(DMA_CH);
the code hault at disable_dma(DMA_CH)
in
thanks for Scott's following
> You need to pass your physical address (0xd000) to ioremap() to
> obtain a virtual address that you can dereference.
actually, i have done that like you said. pass my phy addr to a virtual
addr, but i suppose it is a kernel virtual addr. i wanna get data from p
i want to mapping FIFO memory to bank 3 by configure br3 and or3
the boot info as following.
in my code, i have mapped FIFO to 0xD000, then i red the value from this
address.
the prompts as following
there is some wrong with BRx and ORx set? or something others?
please give me some sugges
hi all:
now there was one question like this following:
there are two chips which are dual-port FIFO memories on my target board.
I attempt two read data with the way of DMA from FIFO to SDRAM
In my point, i need a driver of DMA and a driver of FIFO
but i have no idea at all that what should i do
evolution! kernel 2.6.11 has run on the board with u-boot 1.1.4, also, at
early booting time LEDs are disabled due to MMU on and off. so i tried to
turn LEDs on after start_kernel function, wow, blinking! that is before
start_kernel will be done successfully. then i modified registers mapping in
i
thanks Scott 's following
> I don't quite follow the above, but what I meant is that you need to
> put a mapping in place that covers your LED I/O once you have the MMU on.
> Any mappings that U-boot made will be gone at that point.
i am sorry for my poor expression. i think i have got your mean
thanks Scott
> Another thing that would generally be good is to keep replies on the
> list rather than taking it to private e-mail as soon as someone replies.
> Someone else may have something helpful to say based on your followup,
> or may have the same problem and be helped by the conclusion.
thanks Scott!
> That is very old code; you're more likely to get help when running
> something up-to-date.
i have a latest u-boot-2009.03 updated instead of mine, and kernel version
is instead of 2.6.24.5
> This alternative was listed as text/plain. is not plaintext.
> Please fix your maile
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