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a question of mpc8313, maybe simple

DISCUSSION jumpingProgrammer 2 participants 4 messages Jun 23, 2008 – Jun 24, 2008

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jumpingProgrammer

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#0 lore raw

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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#1 lore raw
Quoted 4 lines · 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

Quoted 8 lines
{
     .....
     request_irq(IRQ,....);
     request_dma(.....);
     ....
}

In request_irq() , i do not know what is the parameter IRQ.

Use pci_dev->irq.

Quoted 1 line

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

author
#2 lore raw

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.

Quoted 30 lines · Scott Wood-2 wrote:
Quoted 5 lines · 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

Quoted 8 lines
{
     .....
     request_irq(IRQ,....);
     request_dma(.....);
     ....
}

In request_irq() , i do not know what is the parameter IRQ.

Use pci_dev->irq.

Quoted 1 line

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
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#3 lore raw
Quoted 6 lines · 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.

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

Quoted 1 line

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

Right.

-Scott