HIPC: Difference between revisions

← Older edit Newer edit →

@@ Line 17: / Line 17: @@
 | 1 || 9-0 || Total word count (in u32's).
 |-
-| 1 || 13-10 || Flags for buf C descriptor. Value 1 = write output data into cmdreply(separate from raw-data). If set to 2, enable buf C descriptor.
+| 1 || 13-10 || Flags for buf C descriptor.
 |-
 | 1 || 31 || Enable handle descriptor.
@@ Line 55: / Line 55: @@
 |}
-=== Buffer descriptor A/B ===
+=== Buffer descriptor X "Pointer" ===
+This one is packed even worse than A, they inserted the bit38-36 of the address ''on top'' of the counter field.
+Officially, the counter is known as "receive index". This one writes to the buffer described in the ReceiveList.
+{| class="wikitable" border="1"
+! Word || Bits || Description
+|-
+| 0 || 5-0 || Bits 5-0 of counter.
+|-
+| 0 || 8-6 || Bit 38-36 of address.
+|-
+| 0 || 11-9 || Bits 11-9 of counter.
+|-
+| 0 || 15-12 || Bit 35-32 of address.
+|-
+| 0 || 31-16 || Size
+|-
+| 1 || || Lower 32-bits of address.
+|}
+=== Buffer descriptor A/B/W "Send"/"Receive"/"Exchange" ===
 This packing is so unnecessarily complex.
@@ Line 74: / Line 95: @@
 |}
-=== Buffer descriptor C ===
+=== Buffer descriptor C "ReceiveList" ===
+There's a 4-bit flag in the main header controlling the behavior of C descriptors.
+If it has value 0, the C descriptor functionality is disabled. If it has value 1, there is no C descriptor. If it has value 2, there is a single C descriptor.
+Otherwise it has (flag-2) C descriptors.
 {| class="wikitable" border="1"
 ! Word || Bits || Description
@@ Line 83: / Line 110: @@
 |-
 | 1 || 31-16 || Size
-|}
-Ignored by kernel unless the cmdreply has bufX-descriptor enabled? Probably copies the data from the cmdreply bufX to this bufC?
-=== Buffer descriptor X ===
-This one is packed even worse than A, they inserted the bit38-36 of the address ''on top'' of the counter field.
-{| class="wikitable" border="1"
-! Word || Bits || Description
-|-
-| 0 || 5-0 || Bits 5-0 of counter.
-|-
-| 0 || 8-6 || Bit 38-36 of address.
-|-
-| 0 || 11-9 || Bits 11-9 of counter.
-|-
-| 0 || 15-12 || Bit 35-32 of address.
-|-
-| 0 || 31-16 || Size
-|-
-| 1 || || Lower 32-bits of address.
 |}