diff options
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/devel/memory.txt | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/docs/devel/memory.txt b/docs/devel/memory.txt index 4fff0d5603..42577e1d86 100644 --- a/docs/devel/memory.txt +++ b/docs/devel/memory.txt @@ -326,8 +326,15 @@ visible as the pci-hole alias clips it to a 0.5GB range. MMIO Operations --------------- -MMIO regions are provided with ->read() and ->write() callbacks; in addition -various constraints can be supplied to control how these callbacks are called: +MMIO regions are provided with ->read() and ->write() callbacks, +which are sufficient for most devices. Some devices change behaviour +based on the attributes used for the memory transaction, or need +to be able to respond that the access should provoke a bus error +rather than completing successfully; those devices can use the +->read_with_attrs() and ->write_with_attrs() callbacks instead. + +In addition various constraints can be supplied to control how these +callbacks are called: - .valid.min_access_size, .valid.max_access_size define the access sizes (in bytes) which the device accepts; accesses outside this range will |