Prioritized address decoder
View Patent ↗A prioritized address decoder has been disclosed. One embodiment of the prioritized address decoder includes a first comparator to compare a destination device address of data with a first address range associated with a first device and a second comparator coupled to the first comparator to compare the destination device address with a second address range associated with a second device, wherein the data is sent to the second device in response to a first output of the first comparator and a second output of the second comparator.
1. A prioritized address decoder comprising:
a first comparator associated with a trusted first destination device to compare a received destination device address for data with a first address range associated with the trusted first destination device, the first comparator sending the data to the first device if the destination device address is within the first address range; and
a second comparator associated with a non-trusted second destination device and coupled to the first comparator to compare the destination device address with a second address range associated with the non-trusted second device, wherein the second comparator sends the data to the second device only if the second comparator receives a first output of the first comparator, the first output indicating that the destination device address does not correspond to the first address range, wherein the first comparator disables the second comparator when the destination device address is within the first address range;
a third comparator coupled to the first and the second comparators to compare the destination device address with a third address range associated with a third device, wherein the data is sent to the third device only if the third comparator receives a third output of the third comparator, the third output indicating that the destination device address does not correspond to the second address range, wherein in the third comparator is disabled when the address is within either the first address range or the second address range.
2. The prioritized address decoder of claim 1 , wherein if the first address range is associated with a first device of a computer system, then secured data in the computer system is authorized to be sent to the first device.
3. The prioritized address decoder of claim 1 , wherein if the second address range is associated with a second device of a computer system, then the secured data is not authorized to be sent to the second device.
4. The prioritized address decoder of claim 1 , wherein the comparators include a plurality of configuration bits corresponding to respective address ranges.
5. The method of claim 4 , wherein the plurality of configuration bits are software configurable.
6. The method of claim 5 , wherein the plurality of configuration bits are locked during a trusted mode.
7. A computer system comprising:
a dynamic random access memory (DRAM);
a memory controller coupled to the DRAM, the memory controller comprising a prioritized address decoder, the prioritized decoder including
a first comparator associated with a trusted first destination device to compare a received destination device address for data with a first address range associated with the trusted first destination device, the first comparator sending the data to the first device if the destination device address is within the first address range; and
a second comparator associated with a non-trusted second destination device and coupled to the first comparator to compare the destination device address with a second address range associated with the non-trusted second device, wherein the second comparator sends the data to the second device only if the second comparator receives a first output of the first comparator, the first output indicating that the destination device address does not correspond to the first address range, wherein the first comparator disables the second comparator when the destination device address is within the first address range;
a third comparator coupled to the first and the second comparators to compare the destination device address with a third address range associated with a third device, wherein the data is sent to the third device only if the third comparator receives a third output of the third comparator, the third output indicating that the destination device address does not correspond to the second address range, wherein in the third comparator is disabled when the address is within either the first address range or the second address range.
8. The computer system of claim 7 , further comprising a processor coupled to the memory controller, wherein the trusted agent is the processor.
9. The computer system of claim 7 , wherein the second address range is associated with agents coupled to an external bus.
10. The computer system of claim 7 , wherein the memory controller further comprises a plurality of configuration registers storing information on the first and the second address ranges.
11. The computer system of claim 10 , wherein the information is stored in the plurality of configuration registers during configuration.
12. The computer system of claim 10 , wherein the plurality of configuration registers are locked during a trusted mode.