I'm writting a PCI device driver that needs to allocate "large"
aligned chunks of DMA memory for the hardware's queues. After loading
and unloading the driver a number of times, bus_dmamem_alloc starts to
fail.
In the device attach, the allocation code looks like (error checking
removed for brevity)
bus_dma_tag_create(NULL, 4, 0, BUS_SPACE_MAXADDR_32BIT,
BUS_SPACE_MAXADDR, NULL, NULL, BUS_SPACE_MAXSIZE_32BIT,
BUS_SPACE_MAXSIZE_32BIT, BUS_SPACE_UNRESTRICTED,
0, &parent);
bus_dma_tag_create(parent, 65536, 0, BUS_SPACE_MAXADDR_32BIT,
BUS_SPACE_MAXADDR, NULL, NULL, 65536, 1, 65536,
0, &child);
bus_dmamem_alloc(child, &virt, BUS_DMA_NOWAIT, &map);
bus_dmamap_load(child, map, virt, 65536, map_request, NULL, 0);
In the device detach, the code that frees up the memory
if (virt != NULL) {
bus_dmamap_unload(child, map);
bus_dmamem_free(child, virt, map);
bus_dmamap_destroy(child, map);
}
bus_dma_tag_destroy(child);
bus_dma_tag_destroy(parent);
I'm clearly doing something wrong, but I don't understand what the
problem is. Any ideas? Thanks!
--
Chuck Tuffli <chuck_tuffli AT NO_SPAM agilent DOT com>
Agilent Technologies, Storage and Networking
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