Changes between Version 73 and Version 74 of library_stdio


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Timestamp:
Apr 12, 2015, 2:36:55 PM (9 years ago)
Author:
alain
Comment:

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  • library_stdio

    v73 v74  
    5151The '''vci_mwmr_dma''' component implements two transfer modes that can be configured by the user application through dedicate system calls.
    5252The user application must use the ''giet_coproc_alloc()'' system call to get a private hardware coprocessor. Then it must use the ''giet_coproc_channel_init()'' system call to configure the TO_COPROC/FROM_COPROC channels.
    53 The coprocessor and the communication channels are activated / deactivated by the ''get_coproc_run()'' system call.
     53The coprocessor and the communication channels are activated by the ''get_coproc_run()'' system call.
    5454 * In '''MODE_MWMR''', each channel FSM  implements the 7 steps MWMR protocol, and transfer an "infinite" data stream, between one coprocessor port and a MWMR software FIFO in memory. The There is no transfer completion signaling, as the synchronisation is done through the MWMR FIFOs. The MWR IRQ is only asserted if a VCI error is reported in memory access.
    55  * In '''MODE_DMA_IRQ''' or '''MODE_DMA_NO_IRQ''', each channel FSM transfers a single buffer between one coprocessor port and the memory. When transfer is completed, the channel FSM keep blocked until it is re-activated. In '''MODE_DMA_IRQ''', the calling task is descheduled, after coprocessor activation, in the ''giet_coproc_run()'' system call. The transfer completion is signaled by the MWR IRQ that updates the ''_coproc_done'' / ''_coproc_status'' variables, deactivates the coprocessor, and resumes the calling task.  In '''MODE_DMA_NO_IRQ''', the ''giet_coproc_start()'' system call is not blocking, and the user task must use the ''giet_coproc_completed()'' system call to detect transfer completion (by polling the coprocessor registers).
     55 * In '''MODE_DMA_IRQ''' or '''MODE_DMA_NO_IRQ''', each channel FSM transfers a single buffer between one coprocessor port and the memory. When transfer is completed, the channel FSM keep blocked until it is re-activated. In '''MODE_DMA_IRQ''', the calling task is descheduled, after coprocessor activation, in the ''giet_coproc_run()'' system call. The transfer completion is signaled by the MWR IRQ that updates the ''_coproc_done'' / ''_coproc_status'' variables, deactivates the coprocessor, and resumes the calling task.  In '''MODE_DMA_NO_IRQ''', the ''giet_coproc_start()'' system call is not blocking. The user task must use the ''giet_coproc_completed()'' system call that detect transfer completion by polling the coprocessor registers, and deactivates the coprocessor before returning.
    5656
    5757'''WARNING''': For a given coprocessor, all channels must be running in the same mode. If this is not the case, the result is unpredictable.