From 529182e204db083cb7bda832d1c5c6d9278ba1cb Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Fri, 29 Jul 2016 18:11:32 -0700 Subject: [PATCH] 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 Signed-off-by: Kees Cook Acked-by: Rob Herring --- .../{misc => reserved-memory}/ramoops.txt | 8 ++-- Documentation/ramoops.txt | 38 +++++++++++++------ drivers/of/platform.c | 20 +++++++++- fs/pstore/ram.c | 23 ++++------- 4 files changed, 56 insertions(+), 33 deletions(-) rename Documentation/devicetree/bindings/{misc => reserved-memory}/ramoops.txt (86%) diff --git a/Documentation/devicetree/bindings/misc/ramoops.txt b/Documentation/devicetree/bindings/reserved-memory/ramoops.txt similarity index 86% rename from Documentation/devicetree/bindings/misc/ramoops.txt rename to Documentation/devicetree/bindings/reserved-memory/ramoops.txt index cd02cec67d38..e81f821a2135 100644 --- a/Documentation/devicetree/bindings/misc/ramoops.txt +++ b/Documentation/devicetree/bindings/reserved-memory/ramoops.txt @@ -2,8 +2,9 @@ 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. +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 @@ -21,8 +22,7 @@ Required properties: - compatible: must be "ramoops" -- memory-region: phandle to a region of memory that is preserved between - reboots +- reg: region of memory that is preserved between reboots Optional properties: diff --git a/Documentation/ramoops.txt b/Documentation/ramoops.txt index 9264bcab4099..26b9f31cf65a 100644 --- a/Documentation/ramoops.txt +++ b/Documentation/ramoops.txt @@ -45,18 +45,34 @@ corrupt, but usually it is restorable. 2. Setting the parameters -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 - and then use the reserved memory for ramoops. For example, assuming a machine - with > 128 MB of memory, the following kernel command line will tell the - kernel to use only the first 128 MB of memory, and place ECC-protected ramoops - region at 128 MB boundary: +Setting the ramoops parameters can be done in several different manners: + + A. 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 and then use the reserved memory for ramoops. For example, assuming a + machine with > 128 MB of memory, the following kernel command line will tell + the 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 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 + + B. Use Device Tree bindings, as described in + Documentation/device-tree/bindings/reserved-memory/ramoops.txt. + For example: + + reserved-memory { + #address-cells = <2>; + #size-cells = <2>; + ranges; + + ramoops@8f000000 { + compatible = "ramoops"; + reg = <0 0x8f000000 0 0x100000>; + record-size = <0x4000>; + console-size = <0x4000>; + }; + }; + + C. 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 diff --git a/drivers/of/platform.c b/drivers/of/platform.c index 765390e3ed8d..8aa197691074 100644 --- a/drivers/of/platform.c +++ b/drivers/of/platform.c @@ -499,8 +499,24 @@ EXPORT_SYMBOL_GPL(of_platform_default_populate); static int __init of_platform_default_populate_init(void) { - if (of_have_populated_dt()) - of_platform_default_populate(NULL, NULL, NULL); + struct device_node *node; + + if (!of_have_populated_dt()) + return -ENODEV; + + /* + * Handle ramoops explicitly, since it is inside /reserved-memory, + * which lacks a "compatible" property. + */ + node = of_find_node_by_path("/reserved-memory"); + if (node) { + node = of_find_compatible_node(node, NULL, "ramoops"); + if (node) + of_platform_device_create(node, NULL, NULL); + } + + /* Populate everything else. */ + of_platform_default_populate(NULL, NULL, NULL); return 0; } diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c index 47516a794011..427eee7570bb 100644 --- a/fs/pstore/ram.c +++ b/fs/pstore/ram.c @@ -486,30 +486,21 @@ static int ramoops_parse_dt(struct platform_device *pdev, struct ramoops_platform_data *pdata) { struct device_node *of_node = pdev->dev.of_node; - struct device_node *mem_region; - struct resource res; + struct resource *res; u32 value; int ret; dev_dbg(&pdev->dev, "using Device Tree\n"); - mem_region = of_parse_phandle(of_node, "memory-region", 0); - if (!mem_region) { - dev_err(&pdev->dev, "no memory-region phandle\n"); - return -ENODEV; - } - - ret = of_address_to_resource(mem_region, 0, &res); - of_node_put(mem_region); - if (ret) { + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) { dev_err(&pdev->dev, - "failed to translate memory-region to resource: %d\n", - ret); - return ret; + "failed to locate DT /reserved-memory resource\n"); + return -EINVAL; } - pdata->mem_size = resource_size(&res); - pdata->mem_address = res.start; + pdata->mem_size = resource_size(res); + pdata->mem_address = res->start; pdata->mem_type = of_property_read_bool(of_node, "unbuffered"); pdata->dump_oops = !of_property_read_bool(of_node, "no-dump-oops"); -- 2.20.1