Arm Limited

Gergely Kiss

Csaba Kelemen

Dominic William Brown

Christopher Vincent Severino

Seow Chuan Lim

Balázs Mészáros

Richard Andrew Paterson

Man Cheung Joseph Yiu

Gábor Móricz

A data processing apparatus includes a plurality of power domains controlled by respective power control signals PCS. Power control circuitry includes mapping circuitry which maps a plurality of power status signals PSS indicative of the power status of respective power domains, and received from those power domains, to form the power control signals which are then supplied power domains. The mapping circuitry may be controlled by mapping parameters stored within a memory mapped array. The mapping parameters may specify that a given power control signal is either sensitive or insensitive to the power status of a particular other power domain within the data processing apparatus-2. The mapping parameters may be fixed or software programmable.

Power control circuitry for controlling power domains

A system and method are provided for controlling a reset procedure. The system has a plurality of power domains, where each power domain comprises a plurality of components, and a plurality of power controllers, wherein each power controller has at last one associated power domain and is arranged to control a supply of power to each associated power domain. The plurality of power controllers are arranged in a hierarchical arrangement comprising two or more hierarchical levels. A given power controller at a given hierarchical level is arranged to implement a reset procedure requiring a reset to be performed in a given reset domain, where the given reset domain comprises at least a subset of the components provided in multiple power domains associated with multiple power controllers provided in at least one hierarchical level below the given hierarchical level. The given power controller is arranged to initiate a reset procedure by issuing a reset entry request for receipt by each of the multiple power controllers. Each power controller is arranged, on accepting the reset entry request, to perform a reset preparation procedure in respect of each associated power domain within the multiple power domains, and then to issue a response signal to confirm that the reset preparation procedure has been performed. In response to detecting that the response signal has been issued by each of the multiple power controllers, the given power controller asserts a reset signal to the multiple power domains providing components of the given reset domain in order to cause the reset to be performed in a synchronised manner in respect of all of the components in the given reset domain.

System and method for controlling a reset procedure

A system and method are provided for controlling power mode transitions. The system has a plurality of power domains, where each power domain has one or more components, and a plurality of power controllers, where each power domain is associated with one of the power controllers. For each power domain, the associated power controller controls transition of that power domain between a plurality of power modes. The power controllers are connected by communication links in order to implement a hierarchical relationship between the power controllers that comprises two or more hierarchical levels. Each power controller other than a highest level power controller in the hierarchical relationship is connected by a communication link to an associated higher level power controller at a higher hierarchical level in the hierarchical relationship. Each given power controller is arranged to implement a power mode transition policy in order to control transition of the associated power domain between the plurality of power modes. The power mode transition policy takes into account power mode information received from any other power controller that a given power controller is connected to by a communication link, so as to constrain the power mode transitions within the associated power domain in accordance with the hierarchical relationship. This provides an efficient and effective mechanism for handling transitions in power modes of power domains that are related to each other, but managed by different power controllers.

System and method for controlling power mode transitions

An integrated circuit () has first and second domains (). The first domain has a power controller () to control the power state of at least one device () in the second domain based on power management signals exchanged on a power management channel () between the first and second domains A reset isolation bridge () is provided on the power management channel () between the first and second domains (). The bridge () has first and second interfaces () to exchange the power management signals with the first and second domains respectively. Isolating circuitry () is provided in the bridge () to respond to a reset indication () indicating reset of one of the first and second domains, to isolate state transitions of the power management signals at the first and second interfaces () from each other.

Reset isolation bridge

A data processing system includes interconnect circuitry providing a plurality of memory transaction paths between one or more transaction masters, including a processor, debugging circuitry and a DMA unit, and one or more transaction slaves including a non-volatile memory, a DRAM memory and an I/O interface. A cache memory is provided between the interconnect circuitry and the non-volatile memory. This cache memory may be a two way set associative cache memory. The cache memory may serve as a read-only cache memory. A cache miss will result in a line fill of a cache line including the target data which was missed. If prefetching is enabled for the cache memory and the transaction was attempting to read a program instruction, then a prefetch operation may be performed in which a further contiguous cache line of data is also fetched into the cache memory upon the cache miss.

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Budapest, Hungary

Gergely Kiss