From: Thierry Reding
The fdtdec_get_carveout() and fdtdec_set_carveout() function can be used
to read a carveout from a given node or add a carveout to a given node
using the standard device tree bindings (involving reserved-memory nodes
and the memory-region property).
Reviewed-by: Simon Glass
Signed-off-by: Thierry Reding
---
Changes in v3:
- add examples to code comments
Changes in v2:
- use debug() instead of printf() to save code size
- fix carveout size computations, was off by one
- use fdtdec_get_addr_size_auto_noparent()
include/fdtdec.h | 81
lib/fdtdec.c | 87
2 files changed, 168 insertions(+)
diff --git a/include/fdtdec.h b/include/fdtdec.h
index b54ed38fb362..13b743f59ab1 100644
--- a/include/fdtdec.h
+++ b/include/fdtdec.h
@@ -1030,6 +1030,8 @@ int fdtdec_set_phandle(void *blob, int node, uint32_t
phandle);
* The phandle returned from the function call can be used to reference this
* reserved memory region from other nodes.
*
+ * See fdtdec_set_carveout() for a more elaborate example.
+ *
* @param blob FDT blob
* @param basename base name of the node to create
* @param carveout information about the carveout region
@@ -1040,6 +1042,85 @@ int fdtdec_add_reserved_memory(void *blob, const char
*basename,
const struct fdt_memory *carveout,
uint32_t *phandlep);
+/**
+ * fdtdec_get_carveout() - reads a carveout from an FDT
+ *
+ * Reads information about a carveout region from an FDT. The carveout is a
+ * referenced by its phandle that is read from a given property in a given
+ * node.
+ *
+ * @param blob FDT blob
+ * @param node name of a node
+ * @param name name of the property in the given node that contains
+ * the phandle for the carveout
+ * @param indexindex of the phandle for which to read the
carveout
+ * @param carveout return location for the carveout information
+ * @return 0 on success or a negative error code on failure
+ */
+int fdtdec_get_carveout(const void *blob, const char *node, const char *name,
+ unsigned int index, struct fdt_memory *carveout);
+
+/**
+ * fdtdec_set_carveout() - sets a carveout region for a given node
+ *
+ * Sets a carveout region for a given node. If a reserved-memory node already
+ * exists for the carveout, the phandle for that node will be reused. If no
+ * such node exists, a new one will be created and a phandle to it stored in
+ * a specified property of the given node.
+ *
+ * As an example, consider the following code snippet:
+ *
+ * const char *node = "/host1x@5000/dc@5424";
+ * struct fdt_memory fb = {
+ * .start = 0x92cb3000,
+ * .end = 0x934b2fff,
+ * };
+ *
+ * fdtdec_set_carveout(fdt, node, "memory-region", 0, "framebuffer", );
+ *
+ * dc@5420 is a display controller and was set up by the bootloader to
+ * scan out the framebuffer specified by "fb". This would cause the following
+ * reserved memory region to be added:
+ *
+ * reserved-memory {
+ * #address-cells = <0x0002>;
+ * #size-cells = <0x0002>;
+ * ranges;
+ *
+ * framebuffer@92cb3000 {
+ * reg = <0x 0x92cb3000 0x 0x0080>;
+ * phandle = <0x004d>;
+ * };
+ * };
+ *
+ * A "memory-region" property will also be added to the node referenced by the
+ * offset parameter.
+ *
+ * host1x@5000 {
+ * ...
+ *
+ * dc@5424 {
+ * ...
+ * memory-region = <0x004d>;
+ * ...
+ * };
+ *
+ * ...
+ * };
+ *
+ * @param blob FDT blob
+ * @param node name of the node to add the carveout to
+ * @param prop_namename of the property in which to store the phandle of
+ * the carveout
+ * @param indexindex of the phandle to store
+ * @param name base name of the reserved-memory node to create
+ * @param carveout information about the carveout to add
+ * @return 0 on success or a negative error code on failure
+ */
+int fdtdec_set_carveout(void *blob, const char *node, const char *prop_name,
+ unsigned int index, const char *name,
+ const struct fdt_memory *carveout);
+
/**
* Set up the device tree ready for use
*/
diff --git a/lib/fdtdec.c b/lib/fdtdec.c
index be54ad5bd092..bd05ab90fce1 100644
--- a/lib/fdtdec.c
+++ b/lib/fdtdec.c
@@ -1381,6 +1381,93 @@ int fdtdec_add_reserved_memory(void *blob, const char
*basename,
return 0;
}
+int fdtdec_get_carveout(const void *blob, const char *node, const char *name,
+ unsigned int index, struct fdt_memory *carveout)
+{
+ const fdt32_t *prop;
+ uint32_t phandle;
+ int offset, len;
+
