Charles Brown wrote: > Eike, > > A followup on the pci_alloc_consistent. Once the hardware has > deposited data into the buffer, how do I copy out of that buffer into a > user space buffer? memcpy_fromio? Do I need to ioremap it, first? > something like; > > // get memory that is usable by DMA > > outmem = pci_alloc_consistent(pdev, PAGE_SIZE, &outmem_phys); > > // tell board about it > > memcpy_toio(dest + 4, &outmem_phys, sizeof(outmem_phys)); Nope, it's easier: pci_alloc_consistent() will return you 2 addresses: the physical one (which you pass to the device) and the "software" one, i.e. what the kernel can see. When you notice that your device is finished you call dma_sync_single_for_cpu() to make sure will be accessible by your CPU(s) (caches and the like need to be noticed) and then you can simply memcpy() from your kernel buffer to whereever you like. Eike
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