Abstract: A system and method for efficiently storing traces of multiple components in an embedded system. A system-on-a-chip (SOC) includes a trace unit for collecting and storing trace history, bus event statistics, or both. The SOC may transfer cache coherent messages across multiple buses between a shared memory and a cache coherent controller. The trace unit includes a trace buffer with multiple physical partitions assigned to subsets of the multiple buses. The number of partitions is less than the number of multiple buses. One or more trace instructions may cause a trace history, trace bus event statistics, local time stamps and a global time-base value to be stored in a physical partition within the trace buffer.

Abstract: In an embodiment, a system includes a memory controller that includes a memory cache and a display controller configured to control a display. The system may be configured to detect that the images being displayed are essentially static, and may be configured to cause the display controller to request allocation in the memory cache for source frame buffer data. In some embodiments, the system may also alter power management configuration in the memory cache to prevent the memory cache from shutting down or reducing its effective size during the idle screen case, so that the frame buffer data may remain cached. During times that the display is dynamically changing, the frame buffer data may not be cached in the memory cache and the power management configuration may permit the shutting down/size reduction in the memory cache.

Abstract: Embodiments of a bridge circuit and system are disclosed that may allow converting transactions from one communication protocol to another. The bridge circuit may be coupled to a first bus employing a first communication protocol, and a second bus employing a second communication protocol. The second bus may include a plurality of virtual channels. The bridge circuit may be configured to receive transactions over the first bus, and convert the transactions to the second communication protocol, and to assign the converted transaction to one of the plurality of virtual channels. The bridge circuit may be further configured store the converted transaction. A plurality of limited throughput signals may be generated by the bridge circuit dependent upon a number of available credits for the plurality of virtual channels.

Abstract: In some embodiments, a system includes a shared, high bandwidth resource (e.g. a memory system), multiple agents configured to communicate with the shared resource, and a communication fabric coupling the multiple agents to the shared resource. The communication fabric may be equipped with limiters configured to limit bandwidth from the various agents based on one or more performance metrics measured with respect to the shared, high bandwidth resource. For example, the performance metrics may include one or more of latency, number of outstanding transactions, resource utilization, etc. The limiters may dynamically modify their limit configurations based on the performance metrics. In an embodiment, the system may include multiple thresholds for the performance metrics, and exceeding a given threshold may include modifying the limiters in the communication fabric. There may be hysteresis implemented in the system as well in some embodiments, to reduce the frequency of transitions between configurations.

Abstract: An SOC implements a security enclave processor (SEP). The SEP may include a processor and one or more security peripherals. The SEP may be isolated from the rest of the SOC (e.g. one or more central processing units (CPUs) in the SOC, or application processors (APs) in the SOC). Access to the SEP may be strictly controlled by hardware. For example, a mechanism in which the CPUs/APs can only access a mailbox location in the SEP is described. The CPU/AP may write a message to the mailbox, which the SEP may read and respond to. The SEP may include one or more of the following in some embodiments: secure key management using wrapping keys, SEP control of boot and/or power management, and separate trust zones in memory.

Abstract: In one embodiment, an SOC includes multiple components including a CPU complex and one or more non-CPU components such as peripheral interface controllers, memory controllers, media components, etc. The SOC also includes an SOC debug control unit, which is coupled to receive detected debug events from the components. Each component may include a local debug control unit that is configured to monitor for various debug events within that component. The debug events may be specific to the component. The local debug control units may transmit detected events to the SOC debug control unit. The SOC debug control unit may detect one or more events from one or more components, and may halt the components of the SOC responsive to detecting the selected events.

Abstract: In an embodiment, a system includes an interrupt controller, one or more CPUs coupled to the interrupt controller, a communication fabric, one or more peripheral devices configured to generate interrupts to be transmitted to the interrupt controller, and one or more interrupt message circuits coupled to the peripheral devices. The interrupt message circuits are configured to generate interrupt messages to convey the interrupts over the fabric to the interrupt controller. Some of the interrupts are level-sensitive interrupts, and the interrupt message circuits are configured to transmit level-sensitive interrupt messages to the interrupt controller. At least one of the interrupts is edge-triggered. The system is configured to convert the edge-triggered interrupt to a level-sensitive interrupt so that interrupts may be handled in the same fashion.

Abstract: In an embodiment, a system includes at least one peripheral device, an interrupt controller, a memory controller, at least one CPU, and an interrupt message circuit coupled to the peripheral device. The interrupt message circuit may be coupled to receive the interrupt signal from the peripheral device, and may be configured to generate an interrupt message for transmission on a communication fabric. In some embodiments, there may be multiple peripherals which have independent paths through the fabric for memory operations to the memory controller. Each such peripheral may be coupled to an instance of the interrupt message circuit. In an embodiment, the interrupt is level sensitive. The interrupt message circuit may be configured to transmit interrupt set messages an interrupt clear messages to the interrupt controller, to indicate the levels.

Abstract: A system and method for maintaining accurate interrupt timestamps. A semiconductor chip includes an interrupt controller (IC) with an interface to multiple sources of interrupts. In response to receiving an interrupt, the IC copies and records the value stored in a main time base counter used for maintaining a global elapsed time. The IC sends an indication of the interrupt to a corresponding processor. Either an interrupt service routine (ISR) or a device driver requests a timestamp associated with the interrupt. Rather than send a request to the operating system to obtain a current value stored in the main time base counter, the processor requests the recorded timestamp from the IC. The IC identifies the stored timestamp associated with the interrupt and returns it to the processor.

Abstract: An SOC implements a security enclave processor (SEP). The SEP may include a processor and one or more security peripherals. The SEP may be isolated from the rest of the SOC (e.g. one or more central processing units (CPUs) in the SOC, or application processors (APs) in the SOC). Access to the SEP may be strictly controlled by hardware. For example, a mechanism in which the CPUs/APs can only access a mailbox location in the SEP is described. The CPU/AP may write a message to the mailbox, which the SEP may read and respond to. The SEP may include one or more of the following in some embodiments: secure key management using wrapping keys, SEP control of boot and/or power management, and separate trust zones in memory.

Abstract: In some embodiments, a system includes a shared, high bandwidth resource (e.g. a memory system), multiple agents configured to communicate with the shared resource, and a communication fabric coupling the multiple agents to the shared resource. The communication fabric may be equipped with limiters configured to limit bandwidth from the various agents based on one or more performance metrics measured with respect to the shared, high bandwidth resource. For example, the performance metrics may include one or more of latency, number of outstanding transactions, resource utilization, etc. The limiters may dynamically modify their limit configurations based on the performance metrics. In an embodiment, the system may include multiple thresholds for the performance metrics, and exceeding a given threshold may include modifying the limiters in the communication fabric. There may be hysteresis implemented in the system as well in some embodiments, to reduce the frequency of transitions between configurations.

Abstract: An SOC implements a security enclave processor (SEP). The SEP may include a processor and one or more security peripherals. The SEP may be isolated from the rest of the SOC (e.g. one or more central processing units (CPUs) in the SOC, or application processors (APs) in the SOC). Access to the SEP may be strictly controlled by hardware. For example, a mechanism in which the CPUs/APs can only access a mailbox location in the SEP is described. The CPU/AP may write a message to the mailbox, which the SEP may read and respond to. The SEP may include one or more of the following in some embodiments: secure key management using wrapping keys, SEP control of boot and/or power management, and separate trust zones in memory.

Abstract: A system and method for efficiently monitoring traces of multiple components in an embedded system. A system-on-a-chip (SOC) includes a trace unit for collecting and storing trace history, bus event statistics, or both. The SOC may transfer cache coherent messages across multiple buses between a shared memory and a cache coherent controller. The trace unit includes multiple bus event filters. Programmable configuration registers are used to assign the bus event filters to selected buses for monitoring associated bus traffic and determining whether qualified bus events occur. If so, the bus event filters increment an associated count for each of the qualified bus events. The values used for determining qualified bus events may be set by programmable configuration registers.

Abstract: A system and method for efficiently storing traces of multiple components in an embedded system. A system-on-a-chip (SOC) includes a trace unit for collecting and storing trace history, bus event statistics, or both. The SOC may transfer cache coherent messages across multiple buses between a shared memory and a cache coherent controller. The trace unit includes a trace buffer with multiple physical partitions assigned to subsets of the multiple buses. The number of partitions is less than the number of multiple buses. One or more trace instructions may cause a trace history, trace bus event statistics, local time stamps and a global time-base value to be stored in a physical partition within the trace buffer.

Abstract: In one embodiment, an SOC includes multiple components including a CPU complex and one or more non-CPU components such as peripheral interface controllers, memory controllers, media components, etc. The SOC also includes an SOC debug control unit, which is coupled to receive detected debug events from the components. Each component may include a local debug control unit that is configured to monitor for various debug events within that component. The debug events may be specific to the component. The local debug control units may transmit detected events to the SOC debug control unit. The SOC debug control unit may detect one or more events from one or more components, and may halt the components of the SOC responsive to detecting the selected events.

Abstract: Smart routing between peers in a point-to-point link based system begins when a device of a plurality of devices in a point-to-point link interconnected system receives a packet from an upstream link or a downstream link. The processing continues when the device interprets the packet to determine a destination of the packet. If the device is the destination of the packet, the device accepts the packet. If, however, the device is not the destination of the packet, the device forwards the packet on another upstream link or another downstream link without alteration of at least one of: source information of the packet and destination information of the packet.

Abstract: Techniques are disclosed relating to integrated circuits that implement a virtual memory. In one embodiment, an integrated circuit is disclosed that includes a translation lookaside buffer configured to store non-prefetched translations and a translation table configured to store prefetched translations. In such an embodiment, the translation lookaside buffer and the translation table share table walk circuitry. In some embodiments, the table walk circuitry is configured to store a translation in the translation table in response to a prefetch request and without updating the translation lookaside buffer. In some embodiments, the translation lookaside buffer, the translation table, and table walk circuitry are included within a memory management unit configured to service memory requests received from a plurality of client circuits via a plurality of direct memory access (DMA) channels.

Abstract: A multiple processor device generates a control packet for at least one connectionless-based packet in partial accordance with a control packet format of the connection-based point-to-point link and partially not in accordance with the control packet format. For instance, the multiple processor device generates the control packet to include, in noncompliance with the control packet format, one or more of an indication that at least one connectionless-based packet is being transported, an indication of a virtual channel of a plurality of virtual channels associated with the at least one connectionless-based packet, an indication of an amount of data included in the associated data packet, status of the at least one connectionless-based packet, and an error status indication.

Abstract: A dual mode digital interface supports the HyperTransport Standard and at least one other interface standard. The dual mode digital interface includes a plurality of data line deskew/sampling blocks, a data group deskew module, and an enablement control module. The plurality of data line deskew/sampling blocks deskew and sample incoming data on respective data lines based upon a clock signal to produce deskewed data. The data group deskew module receives deskewed data from each of the plurality of data line deskew/sampling blocks and removes inter-data line skew from the deskewed data to produce received data. The plurality of data line deskew/sampling blocks and the data group deskew module can be configured in a first mode when supporting an aspect of the HyperTransport Standard and configured in a second mode when supporting the at least one other interface standard.

Abstract: Smart routing between peers in a point-to-point link based system begins when a device of a plurality of devices in a point-to-point link interconnected system receives a packet from an upstream link or a downstream link. The processing continues when the device interprets the packet to determine a destination of the packet. If the device is the destination of the packet, the device accepts the packet. If, however, the device is not the destination of the packet, the device forwards the packet on another upstream link or another downstream link without alteration of at least one of: source information of the packet and destination information of the packet.