Lines Matching refs:in
11 algorithm in use.
27 means that we need some coordination in order to ensure that critical
36 methods of coordination are required in order to guarantee safe
39 The mechanism presented in this document describes a coherent memory
71 level. A CPU in this state is not necessarily being used
79 Each CPU has one of these states assigned to it at any point in time.
80 The CPU states are described in the "CPU state" section, below.
84 to introduce additional states in order to avoid races between different
85 CPUs in the cluster simultaneously modifying the state. The cluster-
86 level states are described in the "Cluster state" section.
88 To help distinguish the CPU states from cluster states in this
96 In this algorithm, each individual core in a multi-core processor is
98 therefore, a CPU can only be doing one thing at a single point in time.
102 The algorithm defines the following states for each CPU in the system:
152 A CPU cannot start participating in hardware coherency until the
154 then the CPU will wait in the CPU_COMING_UP state until the
158 Conditions: The CPU's parent cluster must be in CLUSTER_UP.
167 start participating in local coherency.
178 The CPU remains in this state until an explicit policy decision
188 While in this state, the CPU exits coherency, including any
209 In order to enable safe coordination in such situations, it is important
227 The different pairings of these states results in six possible
257 be decided in advance by some other means. Refer to the section
266 INBOUND_NOT_COMING_UP (corresponding to GOING_DOWN in the basic
268 COMING_UP in the basic model). The second path avoids cluster
271 CLUSTER_UP/INBOUND_COMING_UP is equivalent to UP in the basic
278 The next state in each case is notated
303 in order to achieve this.
306 setup to enable other CPUs in the cluster to enter coherency
317 enabled for the cluster. Other CPUs in the cluster can safely
332 enabled for the cluster. Other CPUs in the cluster can safely
335 The cluster will remain in this state until a policy decision is
346 must wait in this state until all CPUs in the cluster are in the
349 When all CPUs are in the CPU_DOWN state, the cluster can be torn
379 come online in the meantime and is trying to set up the cluster
388 in the CLUSTER_DOWN state; the inbound CPU will
392 unnecessary teardown and setup operations in situations where
431 Because CPUs may power up asynchronously in response to external wake-up
438 coherency controls in the bus fabric.
440 The current implementation in mcpm_head.S uses a separate mutual exclusion
441 mechanism to do this arbitration. This mechanism is documented in
442 detail in vlocks.txt.
461 low-level power-up code in mcpm_head.S. This could
462 involve CPU-specific setup code, but in the current
467 and from there to CLUSTER_DOWN or back to CLUSTER_UP (in
475 the low-level power-up code in mcpm_head.S. This
493 Originally created and documented by Dave Martin for Linaro Limited, in
498 License, as defined in linux/COPYING.