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authorGreg Hackmann <ghackmann@google.com>2016-01-08 02:40:56 +0300
committerKees Cook <keescook@chromium.org>2016-06-14 21:34:39 +0300
commit35da60941e44dbf57868e67686dd24cc1a33125a (patch)
tree9c260e87ab53015553e1e254ce6872f1cd8f1032 /Documentation/devicetree/bindings/misc
parentcae7316708c45e4cfdc586c2e0a02eaea398e246 (diff)
downloadlinux-35da60941e44dbf57868e67686dd24cc1a33125a.tar.xz
pstore/ram: add Device Tree bindings
ramoops is one of the remaining places where ARM vendors still rely on board-specific shims. Device Tree lets us replace those shims with generic code. These bindings mirror the ramoops module parameters, with two small differences: (1) dump_oops becomes an optional "no-dump-oops" property, since ramoops sets dump_oops=1 by default. (2) mem_type=1 becomes the more self-explanatory "unbuffered" property. Signed-off-by: Greg Hackmann <ghackmann@google.com> [fixed platform_get_drvdata() crash, thanks to Brian Norris] [switched from u64 to u32 to simplify code, various whitespace fixes] [use dev_of_node() to gain code-elimination for CONFIG_OF=n] Signed-off-by: Kees Cook <keescook@chromium.org>
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diff --git a/Documentation/devicetree/bindings/misc/ramoops.txt b/Documentation/devicetree/bindings/misc/ramoops.txt
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+Ramoops oops/panic logger
+=========================
+
+ramoops provides persistent RAM storage for oops and panics, so they can be
+recovered after a reboot. It is a backend to pstore, so this node 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"
+
+- memory-region: phandle to a 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)