The HyperNews Linux KHG Discussion Pages

## PCI DMA transfers...

  Forum: Device Drivers
  Re: Physical Address to Point DMA data to (John Huggins)
  Date: Wed, 19 Nov 1997 20:42:38 GMT
  From: David M. Rector <drector@lanl.gov>

I have been trying to deal with the same issues, transfer a large chunck of data directly to memory using DMA, however my understanding is that kernel memory is divided into ALOT of 4k blocks, and any given 4k block can be anywhere, physically in memory based on the page tables. I was told, a while ago that there are only two ways to do it.
    1) use the page tables to find out where each 4k block is,
    	then transfer 4k at a time
    2) reserve a block of memory at boot time, then use that
    	space as "buffer" memory. You may even be able to
    	get a pointer to it.
Dave Rector drector@lanl.gov