SPRZ397K November   2012  – September 2024 TDA2EG-17 , TDA2HF , TDA2HG , TDA2HV , TDA2LF , TDA2SA , TDA2SG , TDA2SX

 

  1.   1
  2. 1Introduction
    1.     Related Documentation
    2.     Trademarks
    3.     Modules Impacted
  3. 2Silicon Advisories
    1.     Revisions SR 2.0, 1.1, 1.0 - Advisories List
    2.     i202
    3.     i378
    4.     i631
    5.     i694
    6.     i698
    7.     i699
    8.     i727
    9.     i729
    10.     i734
    11.     i767
    12.     i782
    13.     i783
    14.     i802
    15.     i803
    16.     i807
    17.     i808
    18.     i809
    19.     i810
    20.     i813
    21.     i814
    22.     i815
    23.     i818
    24.     i819
    25.     i820
    26.     i824
    27.     i826
    28.     i829
    29.     i834
    30.     i837
    31.     i840
    32.     i841
    33.     i842
    34.     i843
    35.     i847
    36.     i849
    37.     i852
    38.     i854
    39.     i855
    40.     i856
    41.     i859
    42.     i861
    43.     i862
    44.     i863
    45.     i868
    46.     i869
    47.     i870
    48.     i871
    49.     i872
    50.     i874
    51.     i875
    52.     i878
    53.     i879
    54.     i880
    55.     i882
    56.     i883
    57.     i884
    58.     i887
    59.     i889
    60.     i890
    61.     i893
    62.     i895
    63.     i896
    64.     i897
    65.     i898
    66.     i899
    67.     i900
    68.     i901
    69.     i903
    70.     i916
    71.     i927
    72.     i929
    73.     i930
    74.     i932
    75.     i933
    76.     i936
    77.     i940
    78.     i2446
  4. 3Silicon Limitations
    1.     Revisions SR 2.0, 1.1, 1.0 - Limitations List
    2.     i596
    3.     i641
    4.     i833
    5.     i838
    6.     i844
    7.     i845
    8.     i848
    9.     i850
    10.     i851
    11.     i853
    12.     i857
    13.     i858
    14.     i876
    15.     i877
    16.     i892
    17.     i909
  5. 4Silicon Cautions
    1.     Revisions SR 2.0, 1.1, 1.0 - Cautions List
    2.     i781
    3. 4.1 106
    4.     i827
    5.     i832
    6.     i836
    7.     i839
    8.     i864
    9.     i885
    10.     i886
    11.     i912
    12.     i926
    13.     i931
    14.     i935
  6. 5Revision History

i898

DSP Pre-fetch Should Be Disabled before Entering Power Down Mode

CRITICALITY

Medium

DESCRIPTION

The DSP may hang after multiple iterations of going into C66x Corepac Power Down and wake up from external events.

The C66x XMC (External Memory Controller) can have outstanding pre-fetch requests when C66x Corepac transitions to a Power Down state. The XMC clocks are gated internally during this transition. While XMC clocks are gated, outstanding pre-fetch request responses are not seen by the XMC which leads to an inconsistent state between the XMC and the L3 Interconnect. When the DSP wakes up, this can manifest as different symptoms within the DSP subsystem, including Cache corruption, incorrect data being returned to the CPU, and can eventually lead to a DSP hang condition.

WORKAROUND

The steps to avoid this issue are as given below:

  1. Ensure the code which places the DSP C66x Corepac to Power Down State (power down entry procedure shown below) is placed in the DSP C66x L2 RAM memory.
  2. Set the IDLE bit in PDCCMD register during initialization.
  3. Inside the power down entry procedure include the following software sequence:
    1. Execute MFENCE instruction.
    2. Write 1 to XPFCMD.INV (address 0x0800_0300).
    3. Read XPFACS (address 0x0800_0304).
    4. Execute IDLE instruction.

While executing multi-threaded DSP software with C66x Corepac Power Down caution should be observed to not allow the power down entry sequence to be preempted and switch context.

The software developer can choose to not perform the above software sequence by never enabling the DSP C66x Pre-fetch. The developer should understand the impact of not enabling DSP Pre-fetch on the DSP CPU memory access performance in their application.

REVISIONS IMPACTED

SR 2.0, 1.1, 1.0

TDA2x: 2.0, 1.1, 1.0

DRA75x, DRA74x: 2.0, 1.1, 1.0

AM572x: 2.0, 1.1