Visible to Intel only — GUID: iga1443129828193
Ixiasoft
Visible to Intel only — GUID: iga1443129828193
Ixiasoft
31.7.1.4.2. Control Register
The address offset for the Control Register table is 0x0.
Bit | Fields | Access | Default Value | Description |
---|---|---|---|---|
31:5 | Reserved | R | 0x0 | Reserved fields |
4 | Park Mode | R/W | 0x0 | This bit enables the mSGDMA to repeatedly execute the same linked list over and over again. In order for this to work, software need to setup the last descriptor to point back to the first descriptor. 1: Park mode is enabled. Pefetcher will not clear the owned by hardware field during descriptor write back 0: Park mode is disabled. Prefetcher will clear the owned by hardware field during descriptor write back. Software can terminate the park mode operation by clearing this field. Since this field is in CSR and not in descriptor field itself, this termination event is asynchronous to current descriptor in progress (user can’t deterministically choose which descriptor in the linked list to stop). Park mode feature is not intended to be used on the fly. User must not enable this bit when the Prefetcher is already in operation. This bit shall be set during initialization/configuration phase of the control register. |
3 | Global Interrupt Enable Mask | R/W | 0x0 | Setting this bit will allow interrupts to propagate to the interrupt sender port. This mask occurs before the register logic so any interrupt events that are triggered when the mask is disabled will not be latched by IRQ register bit in status register.
Note: There is an equivalent global interrupt enable mask bit in dispatcher core CSR. When the Prefetcher is enabled, software shall use this bit. When the Prefetcher is disabled, software shall use equivalent global interrupt enable mask bit in dispatcher core CSR.
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2 | Reset_Prefetcher | R/W1S40 | 0x0 | This bit is used when software intends to stop the Prefetcher core when it is in the middle of data transfer. When this bit is 1, the Prefetcher core begin its reset sequence. This bit is automatically cleared by hardware when the reset sequence has completed. Therefore, software need to poll for this bit to be cleared by hardware to ensure the reset sequence has finished. This function is intended to be used along with reset dispatcher function in dispatcher core. Once the reset sequence in the Prefetcher core has completed, software is expected to reset the dispatcher core, polls for dispatcher’s reset sequence to be completed by reading dispatcher core status register. |
1 | Desc_Poll_En | R/W | 0x0 | Descriptor polling enable bit. 1: When the last descriptor in current linked list has been processed, the Prefetcher core polls the Owned By Hardware bit of next descriptor to be set and automatically resumes data transfer without the need for software to set the Run bit. The polling frequency is specified in Desc_Poll_Freq register. 0: When the last descriptor in current linked list has been processed, the Prefetcher stops operation and clears the run bit. In order to restart the DMA engine, software need to set the Run bit back to 1. In case software intends to disable polling operation in the middle of transfer, software can write this field to 0. In this case, the whole mSGDMA operation is stopped when the Prefetcher core encounter owned by hardware bit = 0.
Note: This bit should be set during initialization or configuration of the control register.
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0 | Run | R/W1S | 0x0 | Software sets this bit to 1 to start the descriptor fetching operation which subsequently initiates the DMA transaction. When descriptor polling is disabled, this bit is automatically cleared by hardware when the last descriptor in the descriptor list has been processed or when the Prefetcher core read owned by hardware bit = 0. When descriptor polling is enabled, mSGDMA operation is continuously run. Thus the run bit stays 1. This field is also cleared by hardware when reset sequence process triggered by Reset_Prefetcher bit completes. |