devres: add devm_kmalloc() and friends (managed memory allocators)

devm_kmalloc() is identical to kmalloc() except that the memory
allocated with it is managed and will be automatically released
when the device is removed/unbound.

Likewise for the other variants.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Simon Glass <sjg@chromium.org>

drivers/core/devres.c

@@ -194,3 +194,37 @@ void devres_release_all(struct udevice *dev)
 {
 	release_nodes(dev, &dev->devres_head, false);
 }
+
+/*
+ * Managed kmalloc/kfree
+ */
+static void devm_kmalloc_release(struct udevice *dev, void *res)
+{
+	/* noop */
+}
+
+static int devm_kmalloc_match(struct udevice *dev, void *res, void *data)
+{
+	return res == data;
+}
+
+void *devm_kmalloc(struct udevice *dev, size_t size, gfp_t gfp)
+{
+	void *data;
+
+	data = _devres_alloc(devm_kmalloc_release, size, gfp);
+	if (unlikely(!data))
+		return NULL;
+
+	devres_add(dev, data);
+
+	return data;
+}
+
+void devm_kfree(struct udevice *dev, void *p)
+{
+	int rc;
+
+	rc = devres_destroy(dev, devm_kmalloc_release, devm_kmalloc_match, p);
+	WARN_ON(rc);
+}

include/dm/device.h

@@ -14,6 +14,8 @@
 #include <dm/uclass-id.h>
 #include <fdtdec.h>
 #include <linker_lists.h>
+#include <linux/compat.h>
+#include <linux/kernel.h>
 #include <linux/list.h>
 
 struct driver_info;
@@ -605,4 +607,46 @@ int devres_destroy(struct udevice *dev, dr_release_t release,
 int devres_release(struct udevice *dev, dr_release_t release,
 		   dr_match_t match, void *match_data);
 
+/* managed devm_k.alloc/kfree for device drivers */
+/**
+ * devm_kmalloc - Resource-managed kmalloc
+ * @dev: Device to allocate memory for
+ * @size: Allocation size
+ * @gfp: Allocation gfp flags
+ *
+ * Managed kmalloc.  Memory allocated with this function is
+ * automatically freed on driver detach.  Like all other devres
+ * resources, guaranteed alignment is unsigned long long.
+ *
+ * RETURNS:
+ * Pointer to allocated memory on success, NULL on failure.
+ */
+void *devm_kmalloc(struct udevice *dev, size_t size, gfp_t gfp);
+static inline void *devm_kzalloc(struct udevice *dev, size_t size, gfp_t gfp)
+{
+	return devm_kmalloc(dev, size, gfp | __GFP_ZERO);
+}
+static inline void *devm_kmalloc_array(struct udevice *dev,
+				       size_t n, size_t size, gfp_t flags)
+{
+	if (size != 0 && n > SIZE_MAX / size)
+		return NULL;
+	return devm_kmalloc(dev, n * size, flags);
+}
+static inline void *devm_kcalloc(struct udevice *dev,
+				 size_t n, size_t size, gfp_t flags)
+{
+	return devm_kmalloc_array(dev, n, size, flags | __GFP_ZERO);
+}
+
+/**
+ * devm_kfree - Resource-managed kfree
+ * @dev: Device this memory belongs to
+ * @p: Memory to free
+ *
+ * Free memory allocated with devm_kmalloc().
+ */
+void devm_kfree(struct udevice *dev, void *p);
+
+
 #endif