ramoops: use DT reserved-memory bindings

Instead of a ramoops-specific node, use a child node of /reserved-memory.
This requires that of_platform_device_create() be explicitly called
for the node, though, since "/reserved-memory" does not have its own
"compatible" property.

Suggested-by: Rob Herring <robh@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Rob Herring <robh@kernel.org>

1 files changed, 48 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/reserved-memory/ramoops.txt b/Documentation/devicetree/bindings/reserved-memory/ramoops.txt
new file mode 100644
index 000000000000..e81f821a2135
--- /dev/null
+++ b/Documentation/devicetree/bindings/reserved-memory/ramoops.txt
@@ -0,0 +1,48 @@
+Ramoops oops/panic logger
+=========================
+
+ramoops provides persistent RAM storage for oops and panics, so they can be
+recovered after a reboot. This is a child-node of "/reserved-memory", and
+is named "ramoops" after the backend, rather than "pstore" which is the
+subsystem.
+
+Parts of this storage may be set aside for other persistent log buffers, such
+as kernel log messages, or for optional ECC error-correction data.  The total
+size of these optional buffers must fit in the reserved region.
+
+Any remaining space will be used for a circular buffer of oops and panic
+records.  These records have a configurable size, with a size of 0 indicating
+that they should be disabled.
+
+At least one of "record-size", "console-size", "ftrace-size", or "pmsg-size"
+must be set non-zero, but are otherwise optional as listed below.
+
+
+Required properties:
+
+- compatible: must be "ramoops"
+
+- reg: region of memory that is preserved between reboots
+
+
+Optional properties:
+
+- ecc-size: enables ECC support and specifies ECC buffer size in bytes
+  (defaults to 0: no ECC)
+
+- record-size: maximum size in bytes of each dump done on oops/panic
+  (defaults to 0: disabled)
+
+- console-size: size in bytes of log buffer reserved for kernel messages
+  (defaults to 0: disabled)
+
+- ftrace-size: size in bytes of log buffer reserved for function tracing and
+  profiling (defaults to 0: disabled)
+
+- pmsg-size: size in bytes of log buffer reserved for userspace messages
+  (defaults to 0: disabled)
+
+- unbuffered: if present, use unbuffered mappings to map the reserved region
+  (defaults to buffered mappings)
+
+- no-dump-oops: if present, only dump panics (defaults to panics and oops)