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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v2 05/15] xen/dts: Add dt_parse_phandle_with_args and dt_parse_phandle
Code adapted from linux drivers/of/base.c (commit ef42c58).
Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
---
Changes in v2:
- Remove hard tabs in dt_parse_phandle
---
xen/common/device_tree.c | 151 ++++++++++++++++++++++++++++++++++++++++-
xen/include/xen/device_tree.h | 54 +++++++++++++++
2 files changed, 203 insertions(+), 2 deletions(-)
diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
index ccdb7ff..564f2bb 100644
--- a/xen/common/device_tree.c
+++ b/xen/common/device_tree.c
@@ -1090,9 +1090,9 @@ int dt_device_get_address(const struct dt_device_node
*dev, int index,
*
* Returns a node pointer.
*/
-static const struct dt_device_node *dt_find_node_by_phandle(dt_phandle handle)
+static struct dt_device_node *dt_find_node_by_phandle(dt_phandle handle)
{
- const struct dt_device_node *np;
+ struct dt_device_node *np;
dt_for_each_device_node(dt_host, np)
if ( np->phandle == handle )
@@ -1477,6 +1477,153 @@ bool_t dt_device_is_available(const struct
dt_device_node *device)
return 0;
}
+static int __dt_parse_phandle_with_args(const struct dt_device_node *np,
+ const char *list_name,
+ const char *cells_name,
+ int cell_count, int index,
+ struct dt_phandle_args *out_args)
+{
+ const __be32 *list, *list_end;
+ int rc = 0, cur_index = 0;
+ u32 size, count = 0;
+ struct dt_device_node *node = NULL;
+ dt_phandle phandle;
+
+ /* Retrieve the phandle list property */
+ list = dt_get_property(np, list_name, &size);
+ if ( !list )
+ return -ENOENT;
+ list_end = list + size / sizeof(*list);
+
+ /* Loop over the phandles until all the requested entry is found */
+ while ( list < list_end )
+ {
+ rc = -EINVAL;
+ count = 0;
+
+ /*
+ * If phandle is 0, then it is an empty entry with no
+ * arguments. Skip forward to the next entry.
+ * */
+ phandle = be32_to_cpup(list++);
+ if ( phandle )
+ {
+ /*
+ * Find the provider node and parse the #*-cells
+ * property to determine the argument length.
+ *
+ * This is not needed if the cell count is hard-coded
+ * (i.e. cells_name not set, but cell_count is set),
+ * except when we're going to return the found node
+ * below.
+ */
+ if ( cells_name || cur_index == index )
+ {
+ node = dt_find_node_by_phandle(phandle);
+ if ( !node )
+ {
+ dt_printk(XENLOG_ERR "%s: could not find phandle\n",
+ np->full_name);
+ goto err;
+ }
+ }
+
+ if ( cells_name )
+ {
+ if ( !dt_property_read_u32(node, cells_name, &count) )
+ {
+ dt_printk("%s: could not get %s for %s\n",
+ np->full_name, cells_name, node->full_name);
+ goto err;
+ }
+ }
+ else
+ count = cell_count;
+
+ /*
+ * Make sure that the arguments actually fit in the
+ * remaining property data length
+ */
+ if ( list + count > list_end )
+ {
+ dt_printk(XENLOG_ERR "%s: arguments longer than property\n",
+ np->full_name);
+ goto err;
+ }
+ }
+
+ /*
+ * All of the error cases above bail out of the loop, so at
+ * this point, the parsing is successful. If the requested
+ * index matches, then fill the out_args structure and return,
+ * or return -ENOENT for an empty entry.
+ */
+ rc = -ENOENT;
+ if ( cur_index == index )
+ {
+ if (!phandle)
+ goto err;
+
+ if ( out_args )
+ {
+ int i;
+
+ WARN_ON(count > MAX_PHANDLE_ARGS);
+ if (count > MAX_PHANDLE_ARGS)
+ count = MAX_PHANDLE_ARGS;
+ out_args->np = node;
+ out_args->args_count = count;
+ for ( i = 0; i < count; i++ )
+ out_args->args[i] = be32_to_cpup(list++);
+ }
+
+ /* Found it! return success */
+ return 0;
+ }
+
+ node = NULL;
+ list += count;
+ cur_index++;
+ }
+
+ /*
+ * Returning result will be one of:
+ * -ENOENT : index is for empty phandle
+ * -EINVAL : parsing error on data
+ * [1..n] : Number of phandle (count mode; when index = -1)
+ */
+ rc = index < 0 ? cur_index : -ENOENT;
+err:
+ return rc;
+}
+
+struct dt_device_node *dt_parse_phandle(const struct dt_device_node *np,
+ const char *phandle_name, int index)
+{
+ struct dt_phandle_args args;
+
+ if (index < 0)
+ return NULL;
+
+ if (__dt_parse_phandle_with_args(np, phandle_name, NULL, 0,
+ index, &args))
+ return NULL;
+
+ return args.np;
+}
+
+
+int dt_parse_phandle_with_args(const struct dt_device_node *np,
+ const char *list_name,
+ const char *cells_name, int index,
+ struct dt_phandle_args *out_args)
+{
+ if ( index < 0 )
+ return -EINVAL;
+ return __dt_parse_phandle_with_args(np, list_name, cells_name, 0,
+ index, out_args);
+}
+
/**
* unflatten_dt_node - Alloc and populate a device_node from the flat tree
* @fdt: The parent device tree blob
diff --git a/xen/include/xen/device_tree.h b/xen/include/xen/device_tree.h
index 7c075d9..d429e60 100644
--- a/xen/include/xen/device_tree.h
+++ b/xen/include/xen/device_tree.h
@@ -112,6 +112,13 @@ struct dt_device_node {
};
+#define MAX_PHANDLE_ARGS 16
+struct dt_phandle_args {
+ struct dt_device_node *np;
+ int args_count;
+ uint32_t args[MAX_PHANDLE_ARGS];
+};
+
/**
* IRQ line type.
*
@@ -621,6 +628,53 @@ void dt_set_range(__be32 **cellp, const struct
dt_device_node *np,
void dt_get_range(const __be32 **cellp, const struct dt_device_node *np,
u64 *address, u64 *size);
+/**
+ * dt_parse_phandle - Resolve a phandle property to a device_node pointer
+ * @np: Pointer to device node holding phandle property
+ * @phandle_name: Name of property holding a phandle value
+ * @index: For properties holding a table of phandles, this is the index into
+ * the table
+ *
+ * Returns the device_node pointer.
+ */
+struct dt_device_node *dt_parse_phandle(const struct dt_device_node *np,
+ const char
*phandle_name,
+ int index);
+
+/**
+ * dt_parse_phandle_with_args() - Find a node pointed by phandle in a list
+ * @np: pointer to a device tree node containing a list
+ * @list_name: property name that contains a list
+ * @cells_name: property name that specifies phandles' arguments count
+ * @index: index of a phandle to parse out
+ * @out_args: optional pointer to output arguments structure (will be filled)
+ *
+ * This function is useful to parse lists of phandles and their arguments.
+ * Returns 0 on success and fills out_args, on error returns appropriate
+ * errno value.
+ *
+ * Example:
+ *
+ * phandle1: node1 {
+ * #list-cells = <2>;
+ * }
+ *
+ * phandle2: node2 {
+ * #list-cells = <1>;
+ * }
+ *
+ * node3 {
+ * list = <&phandle1 1 2 &phandle2 3>;
+ * }
+ *
+ * To get a device_node of the `node2' node you may call this:
+ * dt_parse_phandle_with_args(node3, "list", "#list-cells", 1, &args);
+ */
+int dt_parse_phandle_with_args(const struct dt_device_node *np,
+ const char *list_name,
+ const char *cells_name, int index,
+ struct dt_phandle_args *out_args);
+
#endif /* __XEN_DEVICE_TREE_H */
/*
--
1.7.10.4
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