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>

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 cd02cec..e81f821 100644 (file)
--- 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 9264bca..26b9f31 100644 (file)
--- 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 <linux/pstore_ram.h>

diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 765390e..8aa1976 100644 (file)
--- 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 47516a7..427eee7 100644 (file)
--- 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");