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authorBjorn Andersson <bjorn.andersson@linaro.org>2017-10-11 08:08:54 +0300
committerAndy Gross <andy.gross@linaro.org>2017-10-22 13:06:33 +0300
commiteb297bc716ec2cb3147e6e99002e37058c65cba3 (patch)
tree680bcfbebfe7be6feab741dea7d3c41108330dbc /drivers/of/of_reserved_mem.c
parenta50ff19d0658d8a09026158448894f06a4521f33 (diff)
downloadlinux-eb297bc716ec2cb3147e6e99002e37058c65cba3.tar.xz
of: reserved_mem: Accessor for acquiring reserved_mem
In some cases drivers referencing a reserved-memory region might want to remap the entire region, but when defining the reserved-memory by "size" the client driver has no means to know the associated base address of the reserved memory region. This patch adds an accessor for such drivers to acquire a handle to their associated reserved-memory for this purpose. A complicating factor for the implementation is that the reserved_mem objects are created from the flattened DeviceTree, as such we can't use the device_node address for comparison. Fortunately the name of the node will be used as "name" of the reserved_mem and will be used when building the full_name, so we can compare the "name" with the basename of the full_name to find the match. Reviewed-by: Rob Herring <robh@kernel.org> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org> Signed-off-by: Andy Gross <andy.gross@linaro.org>
Diffstat (limited to 'drivers/of/of_reserved_mem.c')
-rw-r--r--drivers/of/of_reserved_mem.c26
1 files changed, 26 insertions, 0 deletions
diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
index d507c3569a88..b108c7a1f74c 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -397,3 +397,29 @@ void of_reserved_mem_device_release(struct device *dev)
rmem->ops->device_release(rmem, dev);
}
EXPORT_SYMBOL_GPL(of_reserved_mem_device_release);
+
+/**
+ * of_reserved_mem_lookup() - acquire reserved_mem from a device node
+ * @np: node pointer of the desired reserved-memory region
+ *
+ * This function allows drivers to acquire a reference to the reserved_mem
+ * struct based on a device node handle.
+ *
+ * Returns a reserved_mem reference, or NULL on error.
+ */
+struct reserved_mem *of_reserved_mem_lookup(struct device_node *np)
+{
+ const char *name;
+ int i;
+
+ if (!np->full_name)
+ return NULL;
+
+ name = kbasename(np->full_name);
+ for (i = 0; i < reserved_mem_count; i++)
+ if (!strcmp(reserved_mem[i].name, name))
+ return &reserved_mem[i];
+
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(of_reserved_mem_lookup);