a question of mpc8313, maybe simple

a question of mpc8313, maybe simple

[jumpingProgrammer]

i am working with a board of mpc8313 using default mpc8313erdb.dts.
But i do not know how can i correctly use DMA to transport data from memory
to a PCI device.
i tryed this
{
     .....
     request_irq(IRQ,....);
     request_dma(.....);
     ....
}

In request_irq() , i do not know what is the parameter IRQ.
And , i did not find any words about DMA in mpc8313erdb.dts .
So 
1. please tell me what should be the parameter IRQ?
      Is it the irq requested when DMA initialized or another one?
2. If i want initialize DMA, how should i do with mpc8313erdb.dts?


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Re: a question of mpc8313, maybe simple

[Scott Wood]

On Mon, Jun 23, 2008 at 05:48:07AM -0700, jumpingProgrammer wrote:
> i am working with a board of mpc8313 using default mpc8313erdb.dts.
> But i do not know how can i correctly use DMA to transport data from memory
> to a PCI device.
> i tryed this
> {
>      .....
>      request_irq(IRQ,....);
>      request_dma(.....);
>      ....
> }
> 
> In request_irq() , i do not know what is the parameter IRQ.

Use pci_dev->irq.

> And , i did not find any words about DMA in mpc8313erdb.dts .

PCI devices can do bus-mastering DMA themselves; request_dma() is for ISA
devices.

-Scott

Re: a question of mpc8313, maybe simple

[jumpingProgrammer]

Thanks a lot for answer my question.
But i am newhand and not very clear about it.
Do you mean:
1. in this case i do not need to include DMA when i "make menuconfig" ?
        The path is Device Drivers->DMA.
2. in this case i do not need add any DMA information in mpc8313erdb.dts?

Now i am reading PCI driver in kernel 2.6.20 to catch your meaning.


Scott Wood-2 wrote:
> 
> On Mon, Jun 23, 2008 at 05:48:07AM -0700, jumpingProgrammer wrote:
>> i am working with a board of mpc8313 using default mpc8313erdb.dts.
>> But i do not know how can i correctly use DMA to transport data from
>> memory
>> to a PCI device.
>> i tryed this
>> {
>>      .....
>>      request_irq(IRQ,....);
>>      request_dma(.....);
>>      ....
>> }
>> 
>> In request_irq() , i do not know what is the parameter IRQ.
> 
> Use pci_dev->irq.
> 
>> And , i did not find any words about DMA in mpc8313erdb.dts .
> 
> PCI devices can do bus-mastering DMA themselves; request_dma() is for ISA
> devices.
> 
> -Scott
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-dev
> 
> 

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Re: a question of mpc8313, maybe simple

[Scott Wood]

On Mon, Jun 23, 2008 at 06:13:41PM -0700, jumpingProgrammer wrote:
> 
> Thanks a lot for answer my question.
> But i am newhand and not very clear about it.
> Do you mean:
> 1. in this case i do not need to include DMA when i "make menuconfig" ?
>         The path is Device Drivers->DMA.

Right, that's for independent DMA engines, such as for offloading
memory-to-memory copies.

> 2. in this case i do not need add any DMA information in mpc8313erdb.dts?

Right.

-Scott