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question on Exclusive access

tom

Hi All,

I am a bit confused with Exclusive access and Locked access

Would you give me example what scenario master will use exclusive access and Locked access? 

Thanks a lot!

Parents
  • 0 in reply to tom

    I don't know of a specific tutorial that walks through the various cases with examples.  There are some videos online regarding Load link/Store conditional (LL/SC), which is the name for what LDREX/STREX (or LDXR/STXR if you speak ARMv8) provide.  Those videos talk in general principles.  There's some architecture course material online as well.

    If you want more concrete implementation details, you can look at real-world implementations and how they map onto architecture specifications.  For example:

    • Sections 6.5.1 through 6.5.3 of the Cortex-A53 r0p4 TRM (DDI0500G), describe its internal exclusive monitor. 
    • Section B2.9 in the ARMv8 ARM (DDI 0487H.a) walks through how ARM defines the behavior for local and global monitors, along with state machine descriptions.
    • Chapter 6 of the AMBA 5 CHI spec (IHI0050E.b) describes the operation of exclusive accesses in a CHI fabric.
    • Section A7.2 in the AMBA AXI and ACE spec (IHI0020H) describes the operation of exclusive accesses in an AXI fabric.
Reply
  • 0 in reply to tom

    I don't know of a specific tutorial that walks through the various cases with examples.  There are some videos online regarding Load link/Store conditional (LL/SC), which is the name for what LDREX/STREX (or LDXR/STXR if you speak ARMv8) provide.  Those videos talk in general principles.  There's some architecture course material online as well.

    If you want more concrete implementation details, you can look at real-world implementations and how they map onto architecture specifications.  For example:

    • Sections 6.5.1 through 6.5.3 of the Cortex-A53 r0p4 TRM (DDI0500G), describe its internal exclusive monitor. 
    • Section B2.9 in the ARMv8 ARM (DDI 0487H.a) walks through how ARM defines the behavior for local and global monitors, along with state machine descriptions.
    • Chapter 6 of the AMBA 5 CHI spec (IHI0050E.b) describes the operation of exclusive accesses in a CHI fabric.
    • Section A7.2 in the AMBA AXI and ACE spec (IHI0020H) describes the operation of exclusive accesses in an AXI fabric.
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