From 687ac05d71bbb3172e0546248e40483ef43a4813 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Fri, 24 Aug 2018 18:04:22 +0100 Subject: docs/devel/memory.txt: Document _with_attrs accessors When we added the _with_attrs accessors we forgot to mention them in the documentation. Signed-off-by: Peter Maydell Message-Id: <20180824170422.5783-4-peter.maydell@linaro.org> Based-on: <20180802174042.29234-1-peter.maydell@linaro.org> Signed-off-by: Paolo Bonzini --- docs/devel/memory.txt | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'docs/devel/memory.txt') diff --git a/docs/devel/memory.txt b/docs/devel/memory.txt index 4fff0d5..42577e1 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 -- cgit v1.1