57 lines
1.9 KiB
Diff
57 lines
1.9 KiB
Diff
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commit 1c388919d89ca35741e9c4d3255adf87f76f0c06
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Author: Geert Uytterhoeven <geert@linux-m68k.org>
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Date: Sat May 7 20:53:16 2011 +0200
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resources: Add lookup_resource()
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Add a function to find an existing resource by a resource start address.
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This allows to implement simple allocators (with a malloc/free-alike API)
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on top of the resource system.
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Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
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diff --git a/include/linux/ioport.h b/include/linux/ioport.h
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index e9bb22c..63eb429 100644
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--- a/include/linux/ioport.h
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+++ b/include/linux/ioport.h
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@@ -132,6 +132,7 @@ extern int allocate_resource(struct resource *root, struct resource *new,
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resource_size_t,
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resource_size_t),
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void *alignf_data);
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+struct resource *lookup_resource(struct resource *root, resource_size_t start);
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int adjust_resource(struct resource *res, resource_size_t start,
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resource_size_t size);
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resource_size_t resource_alignment(struct resource *res);
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diff --git a/kernel/resource.c b/kernel/resource.c
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index 3ff4017..3b3cedc 100644
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--- a/kernel/resource.c
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+++ b/kernel/resource.c
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@@ -553,6 +553,27 @@ int allocate_resource(struct resource *root, struct resource *new,
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EXPORT_SYMBOL(allocate_resource);
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+/**
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+ * lookup_resource - find an existing resource by a resource start address
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+ * @root: root resource descriptor
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+ * @start: resource start address
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+ *
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+ * Returns a pointer to the resource if found, NULL otherwise
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+ */
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+struct resource *lookup_resource(struct resource *root, resource_size_t start)
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+{
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+ struct resource *res;
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+
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+ read_lock(&resource_lock);
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+ for (res = root->child; res; res = res->sibling) {
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+ if (res->start == start)
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+ break;
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+ }
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+ read_unlock(&resource_lock);
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+
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+ return res;
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+}
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+
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/*
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* Insert a resource into the resource tree. If successful, return NULL,
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* otherwise return the conflicting resource (compare to __request_resource())
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