From 35da60941e44dbf57868e67686dd24cc1a33125a Mon Sep 17 00:00:00 2001 From: Greg Hackmann Date: Thu, 7 Jan 2016 15:40:56 -0800 Subject: 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 [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 --- Documentation/devicetree/bindings/misc/ramoops.txt | 48 ++++++++++++++++++++++ Documentation/ramoops.txt | 6 ++- 2 files changed, 52 insertions(+), 2 deletions(-) create mode 100644 Documentation/devicetree/bindings/misc/ramoops.txt (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/misc/ramoops.txt b/Documentation/devicetree/bindings/misc/ramoops.txt new file mode 100644 index 000000000000..cd02cec67d38 --- /dev/null +++ b/Documentation/devicetree/bindings/misc/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. 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) diff --git a/Documentation/ramoops.txt b/Documentation/ramoops.txt index 5d8675615e59..9264bcab4099 100644 --- a/Documentation/ramoops.txt +++ b/Documentation/ramoops.txt @@ -45,7 +45,7 @@ corrupt, but usually it is restorable. 2. Setting the parameters -Setting the ramoops parameters can be done in 2 different manners: +Setting the ramoops parameters can be done in 3 different manners: 1. Use the module parameters (which have the names of the variables described as before). For quick debugging, you can also reserve parts of memory during boot @@ -54,7 +54,9 @@ Setting the ramoops parameters can be done in 2 different manners: kernel to use only the first 128 MB of memory, and place ECC-protected ramoops region at 128 MB boundary: "mem=128M ramoops.mem_address=0x8000000 ramoops.ecc=1" - 2. Use a platform device and set the platform data. The parameters can then + 2. Use Device Tree bindings, as described in + Documentation/device-tree/bindings/misc/ramoops.txt. + 3. Use a platform device and set the platform data. The parameters can then be set through that platform data. An example of doing that is: #include -- cgit v1.2.3-59-g8ed1b