[PATCH 1/2] of: Implement iterator for phandles
Joerg Roedel
joro at 8bytes.org
Wed Mar 16 09:42:06 PDT 2016
From: Joerg Roedel <jroedel at suse.de>
Getting the arguments of phandles is somewhat limited at the
moement, because the number of arguments supported by core
code is limited to MAX_PHANDLE_ARGS, which is set to 16
currently.
In case of the arm smmu this is not enough, as the 128
supported stream-ids are encoded in device-tree with
arguments to phandles. On some systems with more than 16
stream-ids this causes a WARN_ON being triggered at boot and
an incomplete initialization of the smmu.
This patch-set implements an iterator interface over
phandles which allows to parse out arbitrary numbers of
arguments per phandle. The existing function for parsing
them, __of_parse_phandle_with_args(), is converted to make
use of the iterator.
Signed-off-by: Joerg Roedel <jroedel at suse.de>
---
drivers/of/base.c | 219 ++++++++++++++++++++++++++++++-----------------------
include/linux/of.h | 95 +++++++++++++++++++++++
2 files changed, 220 insertions(+), 94 deletions(-)
diff --git a/drivers/of/base.c b/drivers/of/base.c
index 017dd94..9a5f199 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -1439,119 +1439,150 @@ void of_print_phandle_args(const char *msg, const struct of_phandle_args *args)
printk("\n");
}
-static int __of_parse_phandle_with_args(const struct device_node *np,
- const char *list_name,
- const char *cells_name,
- int cell_count, int index,
- struct of_phandle_args *out_args)
+int of_phandle_iterator_init(struct of_phandle_iterator *it,
+ const struct device_node *np,
+ const char *list_name,
+ const char *cells_name,
+ int cell_count)
{
- const __be32 *list, *list_end;
- int rc = 0, size, cur_index = 0;
- uint32_t count = 0;
- struct device_node *node = NULL;
- phandle phandle;
+ const __be32 *list;
+ int size;
/* Retrieve the phandle list property */
list = of_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;
+ it->np = np;
+ it->node = NULL;
+ it->list = list;
+ it->phandle_end = list;
+ it->list_end = list + size / sizeof(*list);
+ it->cells_name = cells_name;
+ it->cell_count = cell_count;
+ it->cur_index = -1;
- /*
- * 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 = of_find_node_by_phandle(phandle);
- if (!node) {
- pr_err("%s: could not find phandle\n",
- np->full_name);
- goto err;
- }
- }
+ return 0;
+}
- if (cells_name) {
- if (of_property_read_u32(node, cells_name,
- &count)) {
- pr_err("%s: could not get %s for %s\n",
- np->full_name, cells_name,
- node->full_name);
- goto err;
- }
- } else {
- count = cell_count;
- }
+int of_phandle_iterator_next(struct of_phandle_iterator *it)
+{
+ phandle phandle = 0;
+ uint32_t count = 0;
- /*
- * Make sure that the arguments actually fit in the
- * remaining property data length
- */
- if (list + count > list_end) {
- pr_err("%s: arguments longer than property\n",
- np->full_name);
- goto err;
- }
+ if (it->phandle_end >= it->list_end)
+ return -ENOENT;
+
+ if (it->node) {
+ of_node_put(it->node);
+ it->node = NULL;
+ }
+
+ it->list = it->phandle_end;
+ it->cur_index += 1;
+ phandle = be32_to_cpup(it->list++);
+
+ if (phandle) {
+ if (it->cells_name) {
+ it->node = of_find_node_by_phandle(phandle);
+ if (!it->node)
+ goto no_node;
+
+ if (of_property_read_u32(it->node,
+ it->cells_name,
+ &count))
+ goto no_property;
+ } else {
+ count = it->cell_count;
}
- /*
- * 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.
- */
+ if (it->list + count > it->list_end)
+ goto too_many_args;
+ }
+
+ it->phandle_end = it->list + count;
+ it->cur_count = count;
+ it->phandle = phandle;
+
+ return 0;
+
+no_node:
+ pr_err("%s: could not find phandle\n", it->np->full_name);
+
+ return -EINVAL;
+
+no_property:
+ pr_err("%s: could not get %s for %s\n", it->np->full_name,
+ it->cells_name, it->node->full_name);
+
+ return -EINVAL;
+
+too_many_args:
+ pr_err("%s: arguments longer than property\n", it->np->full_name);
+
+ return -EINVAL;
+}
+
+int of_phandle_iterator_args(struct of_phandle_iterator *it,
+ uint32_t *args,
+ int size)
+{
+ int i, count;
+
+ count = it->cur_count;
+
+ if (WARN_ON(size < count))
+ count = size;
+
+ for (i = 0; i < count; i++)
+ args[i] = be32_to_cpup(it->list++);
+
+ return count;
+}
+
+static int __of_parse_phandle_with_args(const struct device_node *np,
+ const char *list_name,
+ const char *cells_name,
+ int cell_count, int index,
+ struct of_phandle_args *out_args)
+{
+ struct of_phandle_iterator it;
+ int rc;
+
+ rc = of_phandle_iterator_init(&it, np, list_name,
+ cells_name, cell_count);
+ if (rc)
+ return rc;
+
+ while ((rc = of_phandle_iterator_next(&it)) == 0) {
+ uint32_t count;
+ int cur_index;
+
+ count = of_phandle_iterator_count(&it);
+ cur_index = of_phandle_iterator_index(&it);
+
rc = -ENOENT;
if (cur_index == index) {
- if (!phandle)
- goto err;
-
- if (out_args) {
- int i;
- if (WARN_ON(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++);
- } else {
- of_node_put(node);
- }
+ if (!of_phandle_iterator_phandle(&it))
+ break;
+
+ rc = 0;
/* Found it! return success */
- return 0;
- }
+ if (!out_args)
+ break;
- of_node_put(node);
- node = NULL;
- list += count;
- cur_index++;
+ out_args->np = of_phandle_iterator_node(&it);
+ out_args->args_count = of_phandle_iterator_args(&it,
+ out_args->args,
+ MAX_PHANDLE_ARGS);
+
+ break;
+ }
}
- /*
- * Unlock node before 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:
- if (node)
- of_node_put(node);
+ of_phandle_iterator_destroy(&it);
+
return rc;
}
diff --git a/include/linux/of.h b/include/linux/of.h
index dc6e396..31e6ee9 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -75,6 +75,19 @@ struct of_phandle_args {
uint32_t args[MAX_PHANDLE_ARGS];
};
+struct of_phandle_iterator {
+ const struct device_node *np;
+ const __be32 *list;
+ const __be32 *list_end;
+ const __be32 *phandle_end;
+ phandle phandle;
+ struct device_node *node;
+ const char *cells_name;
+ int cell_count;
+ int cur_index;
+ uint32_t cur_count;
+};
+
struct of_reconfig_data {
struct device_node *dn;
struct property *prop;
@@ -334,6 +347,50 @@ extern int of_parse_phandle_with_fixed_args(const struct device_node *np,
extern int of_count_phandle_with_args(const struct device_node *np,
const char *list_name, const char *cells_name);
+/* phandle iterator functions */
+extern int of_phandle_iterator_init(struct of_phandle_iterator *it,
+ const struct device_node *np,
+ const char *list_name,
+ const char *cells_name,
+ int cell_count);
+
+static inline void of_phandle_iterator_destroy(struct of_phandle_iterator *it)
+{
+ if (it->node)
+ of_node_put(it->node);
+}
+
+extern int of_phandle_iterator_next(struct of_phandle_iterator *it);
+
+static inline int of_phandle_iterator_index(const struct of_phandle_iterator *it)
+{
+ return it->cur_index;
+}
+
+static inline uint32_t of_phandle_iterator_count(const struct of_phandle_iterator *it)
+{
+ return it->cur_count;
+}
+
+static inline uint32_t of_phandle_iterator_phandle(const struct of_phandle_iterator *it)
+{
+ return it->phandle;
+}
+
+static inline struct device_node *of_phandle_iterator_node(struct of_phandle_iterator *it)
+{
+ if (!it->node)
+ it->node = of_find_node_by_phandle(it->phandle);
+
+ if (it->node)
+ of_node_get(it->node);
+
+ return it->node;
+}
+
+extern int of_phandle_iterator_args(struct of_phandle_iterator *it,
+ uint32_t *args,
+ int size);
extern void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align));
extern int of_alias_get_id(struct device_node *np, const char *stem);
extern int of_alias_get_highest_id(const char *stem);
@@ -608,6 +665,44 @@ static inline int of_count_phandle_with_args(struct device_node *np,
return -ENOSYS;
}
+static inline int of_phandle_iterator_init(struct of_phandle_iterator *it,
+ const struct device_node *np,
+ const char *list_name,
+ const char *cells_name,
+ int cell_count)
+{
+ return -ENOSYS;
+}
+
+static inline void of_phandle_iterator_destroy(struct of_phandle_iterator *it)
+{
+}
+
+static inline int of_phandle_iterator_next(struct of_phandle_iterator *it)
+{
+ return -ENOSYS;
+}
+
+static inline int of_phandle_iterator_index(const struct of_phandle_iterator *it)
+{
+ return -1;
+}
+
+static inline uint32_t of_phandle_iterator_count(const struct of_phandle_iterator *it)
+{
+ return 0;
+}
+
+static inline uint32_t of_phandle_iterator_phandle(const struct of_phandle_iterator *it)
+{
+ return 0;
+}
+
+static inline struct device_node *of_phandle_iterator_node(struct of_phandle_iterator *it)
+{
+ return NULL;
+}
+
static inline int of_alias_get_id(struct device_node *np, const char *stem)
{
return -ENOSYS;
--
1.9.1
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