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This makes all of a machine's memory accessible to remote debugging via FireWire, using the physical response unit (i.e. RDMA) of OHCI-1394 link layer controllers. This requires actual support by the controller. The only ones currently known to support it are Agere/LSI FW643. Most if not all other OHCI-1394 controllers do not implement the optional Physical Upper Bound register. With them, RDMA will continue to be limited to the lowermost 4 GB. firewire-ohci's startup message in the kernel log is augmented to tell whether the controller does expose more than 4 GB to RDMA. While OHCI-1394 allows for a maximum Physical Upper Bound of 0xffff'0000'0000 (near 256 TB), this implementation sets it to 0x8000'0000'0000 (128 TB) in order to avoid interference with applications that require interrupt-served asynchronous request reception at respectively low addresses. Note, this change does not switch remote DMA on. It only increases the range of remote access to all memory (instead of just 4 GB) whenever remote DMA was switched on by other means. The latter is achieved by setting firewire-ohci's remote_dma parameter, or if the physical DMA filter is opened through firewire-sbp2. Derived from patch "firewire: Enable physical DMA above 4GB" by Peter Hurley <peter@hurleysoftware.com> from March 27, 2013. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> |
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| .. | ||
| core-card.c | ||
| core-cdev.c | ||
| core-device.c | ||
| core-iso.c | ||
| core-topology.c | ||
| core-transaction.c | ||
| core.h | ||
| init_ohci1394_dma.c | ||
| Kconfig | ||
| Makefile | ||
| net.c | ||
| nosy-user.h | ||
| nosy.c | ||
| nosy.h | ||
| ohci.c | ||
| ohci.h | ||
| sbp2.c | ||