Abstract: A method includes receiving, by a L2 controller, a request to perform a global operation on a L2 cache and preventing new blocking transactions from entering a pipeline coupled to the L2 cache while permitting new non-blocking transactions to enter the pipeline. Blocking transactions include read transactions and non-victim write transactions. Non-blocking transactions include response transactions, snoop transactions, and victim transactions.

Abstract: In described examples, a processor system includes a processor core generating memory transactions, a lower level cache memory with a lower memory controller, and a higher level cache memory with a higher memory controller having a memory pipeline. The higher memory controller is connected to the lower memory controller by a bypass path that skips the memory pipeline. The higher memory controller: determines whether a memory transaction is a bypass write, which is a memory write request indicated not to result in a corresponding write being directed to the higher level cache memory; if the memory transaction is determined a bypass write, determines whether a memory transaction that prevents passing is in the memory pipeline; and if no transaction that prevents passing is determined to be in the memory pipeline, sends the memory transaction to the lower memory controller using the bypass path.

Abstract: An apparatus includes a CPU core and a L1 cache subsystem including a L1 main cache, a L1 victim cache, and a L1 controller. The apparatus includes a L2 cache subsystem including a L2 main cache, a shadow L1 main cache, a shadow L1 victim cache, and a L2 controller configured to receive a read request from the L1 controller as a single transaction. Read request includes a read address, a first indication of an address and a coherence state of a cache line A to be moved from the L1 main cache to the L1 victim cache to allocate space for data returned in response to the read request, and a second indication of an address and a coherence state of a cache line B to be removed from the L1 victim cache in response to the cache line A being moved to the L1 victim cache.

Abstract: A method includes receiving, by a level two (L2) controller, a first request for a cache line in a shared cache coherence state; mapping, by the L2 controller, the first request to a second request for a cache line in an exclusive cache coherence state; and responding, by the L2 controller, to the second request.

Abstract: In described examples, a processor system includes a processor core that generates memory write requests, a cache memory, and a memory controller. The memory controller has a memory pipeline. The memory controller is coupled to control the cache memory and communicatively coupled to the processor core. The memory controller is configured to receive the memory write requests from the processor core; schedule the memory write requests on the memory pipeline; and contemporaneously with scheduling respective ones of the memory write requests on the memory pipeline, send to the processor core a write acknowledgment confirming that writing of a data payload of the respective memory write request to the cache memory has completed.

Abstract: An apparatus including a CPU core and a L1 cache subsystem coupled to the CPU core. The L1 cache subsystem includes a L1 main cache, a L1 victim cache, and a L1 controller. The apparatus includes a L2 cache subsystem coupled to the L1 cache subsystem. The L2 cache subsystem includes a L2 main cache, a shadow L1 main cache, a shadow L1 victim cache, and a L2 controller. The L2 controller receives an indication from the L1 controller that a cache line A is being relocated from the L1 main cache to the L1 victim cache; in response to the indication, update the shadow L1 main cache to reflect that the cache line A is no longer located in the L1 main cache; and in response to the indication, update the shadow L1 victim cache to reflect that the cache line A is located in the L1 victim cache.

Abstract: An apparatus includes a central processing unit (CPU) core and a cache subsystem coupled to the CPU core. The cache subsystem includes a first memory, a second memory, and a controller coupled to the first and second memories. The controller is configured to receive a transaction from a master, the transaction directed to the first memory and comprising an address; re-calculate an error correcting code (ECC) for a line of data in the second memory associated with the address; determine that a non-correctable error is present in the line of data in the second memory based on a comparison of the re-calculated ECC and a stored ECC for the line of data; and in response to the determination that a non-correctable error is present in the line of data in the second memory, terminate the transaction without accessing the first memory.

Abstract: In described examples, a processor system includes a processor core that generates memory write requests, and a cache memory with a memory controller having a memory pipeline. The cache memory has cache lines of length L. The cache memory has a minimum write length that is less than a cache line length of the cache memory. The memory pipeline determines whether the data payload includes a first chunk and ECC syndrome that correspond to a partial write and are writable by a first cache write operation, and a second chunk and ECC syndrome that correspond to a full write operation that can be performed separately from the first cache write operation. The memory pipeline performs an RMW operation to store the first chunk and ECC syndrome in the cache memory, and performs the full write operation to store the second chunk and ECC syndrome in the cache memory.

Abstract: A method includes receiving a first request to allocate a line in an N-way set associative cache and, in response to a cache coherence state of a way indicating that a cache line stored in the way is invalid, allocating the way for the first request. The method also includes, in response to no ways in the set having a cache coherence state indicating that the cache line stored in the way is invalid, randomly selecting one of the ways in the set. The method also includes, in response to a cache coherence state of the selected way indicating that another request is not pending for the selected way, allocating the selected way for the first request.

Abstract: In described examples, a coherent memory system includes a central processing unit (CPU) and first and second level caches. The memory system can include a pipeline for accessing data stored in one of the caches. Requestors can access the data stored in one of the caches by sending requests at a same time that can be arbitrated by the pipeline.

Abstract: In described examples, a processor system includes a processor core that generates memory write requests, a cache memory, and a memory pipeline of the cache memory. The memory pipeline has a holding buffer, an anchor stage, and an RMW pipeline. The anchor stage determines whether a data payload of a write request corresponds to a partial write. If so, the data payload is written to the holding buffer and conforming data is read from a corresponding cache memory address to merge with the data payload. The RMW pipeline has a merge stage and a syndrome generation stage. The merge stage merges the data payload in the holding buffer with the conforming data to make merged data. The syndrome generation stage generates an ECC syndrome using the merged data. The memory pipeline writes the data payload and ECC syndrome to the cache memory.

Abstract: In described examples, a coherent memory system includes a central processing unit (CPU) and first and second level caches. The CPU is arranged to execute program instructions to manipulate data in at least a first or second secure context. Each of the first and second caches stores a secure code for indicating the at least first or second secure contexts by which data for a respective cache line is received. The first and second level caches maintain coherency in response to comparing the secure codes of respective lines of cache and executing a cache coherency operation in response.

Abstract: An apparatus includes a central processing unit (CPU) core and a cache subsystem coupled to the CPU core. The cache subsystem includes a first memory, a second memory, and a controller coupled to the first and second memories. The controller is configured to execute a sequence of scrubbing transactions on the first memory and execute a functional transaction on the second memory. One of the scrubbing transactions and the functional transaction are executed concurrently.

Abstract: A method includes determining, by a level one (L1) controller, to change a size of a L1 main cache; servicing, by the L1 controller, pending read requests and pending write requests from a central processing unit (CPU) core; stalling, by the L1 controller, new read requests and new write requests from the CPU core; writing back and invalidating, by the L1 controller, the L1 main cache. The method also includes receiving, by a level two (L2) controller, an indication that the L1 main cache has been invalidated and, in response, flushing a pipeline of the L2 controller; in response to the pipeline being flushed, stalling, by the L2 controller, requests received from any master; reinitializing, by the L2 controller, a shadow L1 main cache. Reinitializing includes clearing previous contents of the shadow L1 main cache and changing the size of the shadow L1 main cache.

Abstract: A method includes receiving, by a first stage in a pipeline, a first transaction from a previous stage in pipeline; in response to first transaction comprising a high priority transaction, processing high priority transaction by sending high priority transaction to a buffer; receiving a second transaction from previous stage; in response to second transaction comprising a low priority transaction, processing low priority transaction by monitoring a full signal from buffer while sending low priority transaction to buffer; in response to full signal asserted and no high priority transaction being available from previous stage, pausing processing of low priority transaction; in response to full signal asserted and a high priority transaction being available from previous stage, stopping processing of low priority transaction and processing high priority transaction; and in response to full signal being de-asserted, processing low priority transaction by sending low priority transaction to buffer.

Abstract: A system includes a non-coherent component; a coherent, non-caching component; a coherent, caching component; and a level two (L2) cache subsystem coupled to the non-coherent component, the coherent, non-caching component, and the coherent, caching component. The L2 cache subsystem includes a L2 cache; a shadow level one (L1) main cache; a shadow L1 victim cache; and a L2 controller. The L2 controller is configured to receive and process a first transaction from the non-coherent component; receive and process a second transaction from the coherent, non-caching component; and receive and process a third transaction from the coherent, caching component.

Abstract: An apparatus includes a CPU core and a L1 cache subsystem including a L1 main cache, a L1 victim cache, and a L1 controller. The apparatus includes a L2 cache subsystem coupled to the L1 cache subsystem by a transaction bus and a tag update bus. The L2 cache subsystem includes a L2 main cache, a shadow L1 main cache, a shadow L1 victim cache, and a L2 controller. The L2 controller receives a message from the L1 controller over the tag update bus, including a valid signal, an address, and a coherence state. In response to the valid signal being asserted, the L2 controller identifies an entry in the shadow L1 main cache or the shadow L1 victim cache having an address corresponding to the address of the message and updates a coherence state of the identified entry to be the coherence state of the message.

Abstract: An apparatus includes a CPU core, a first memory cache with a first line size, and a second memory cache having a second line size larger than the first line size. Each line of the second memory cache includes an upper half and a lower half. A memory controller subsystem is coupled to the CPU core and to the first and second memory caches. Upon a miss in the first memory cache for a first target address, the memory controller subsystem determines that the first target address resulting in the miss maps to the lower half of a line in the second memory cache, retrieves the entire line from the second memory cache, and returns the entire line from the second memory cache to the first memory cache.

Abstract: A stream of data is accessed from a memory system using a stream of addresses generated in a first mode of operating a streaming engine in response to executing a first stream instruction. A block cache preload operation is performed on a cache in the memory using a block of addresses generated in a second mode of operating the streaming engine in response to executing a second stream instruction.

Abstract: A stream of data is accessed from a memory system using a stream of addresses generated in a first mode of operating a streaming engine in response to executing a first stream instruction. A block cache management operation is performed on a cache in the memory using a block of addresses generated in a second mode of operating the streaming engine in response to executing a second stream instruction.