diff options
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/device-tree/nx.txt | 42 |
1 files changed, 20 insertions, 22 deletions
diff --git a/doc/device-tree/nx.txt b/doc/device-tree/nx.txt index 6c48956..84c97ac 100644 --- a/doc/device-tree/nx.txt +++ b/doc/device-tree/nx.txt @@ -8,9 +8,25 @@ xscom node, as: /xscom@<xscom_addr>/nx@<nx_addr> With unique xscom and nx addresses. Their compatible node contains -"ibm,power-nx". There is nothing that the OS should directly do with the -NX nodes, instead the specific coprocessor nodes should be used, as -described below. +"ibm,power-nx". + + +NX 842 Coprocessor +------------------ + +This is the memory compression coprocessor, which uses the IBM proprietary +842 compression algorithm and format. Each nx node contains an 842 engine. + +ibm,842-coprocessor-type : CT value common to all 842 coprocessors +ibm,842-coprocessor-instance : CI value unique to all 842 coprocessors + +Access to the coprocessor requires using the ICSWX instruction, which uses +a specific format including a Coprocessor Type (CT) and Coprocessor Instance +(CI) value to address each request to the right coprocessor. The driver should +use the CT and CI values for a particular node to communicate with it. For +all 842 coprocessors in the system, the CT value will (should) be the same, +while each will have a different CI value. The driver can use CI 0 to allow +the hardware to automatically select which coprocessor instance to use. NX RNG Coprocessor @@ -18,7 +34,7 @@ NX RNG Coprocessor This is the Random Number Generator (RNG) coprocessor, which is a part of each NX coprocessor. Each node represents a unique RNG coprocessor. -The nodes are located at: +Its nodes are not under the main nx node, they are located at: /hwrng@<addr> : RNG at address <addr> ibm,chip-id : chip id where the RNG is @@ -27,21 +43,3 @@ reg : address of the register to read from Each read from the RNG register will provide a new random number. -NX 842 Coprocessor ------------------- - -This is the memory compression coprocessor, which uses the IBM proprietary -842 compression algorithm and format. Each node represents a unique 842 -coprocessor. The nodes are located at: - -/ibm,nx842-powernv#<chip-id> : 842 coprocessor on chip <chip-id> -ibm,chip-id : chip id where the 842 is -ibm,coprocessor-type : CT value common to all 842 coprocessors -ibm,coprocessor-instance : CI value unique to all 842 coprocessors - -Access to the coprocessor requires using the ICSWX instruction, which uses -a specific format including a Coprocessor Type (CT) and Coprocessor Instance (CI) -value to address each request to the right coprocessor. The system should -use the CT and CI values for a particular node to communicate with it. For -all 842 coprocessors in the system, the CT value will (should) be the same, -while each will have a different CI value. |