[PATCH v2 1/2] of: Make of_find_property_value_of_size take a length range

From: Richard Fitzgerald
Date: Mon Sep 12 2016 - 09:01:47 EST


In preparation for adding variable-length array reads, change
of_find_property_value_of_size so that it takes an optional
maximum length. If the maximum is passed as 0, the behaviour is
unchanged and it will return a property if it's >= the requested
minimum length. If maximum is non-zero it will only return a
property whose length is min <= l <= max.

Signed-off-by: Richard Fitzgerald <rf@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
---
drivers/of/base.c | 39 +++++++++++++++++++++++++++++----------
1 file changed, 29 insertions(+), 10 deletions(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 3ce6953..b853737 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -1146,16 +1146,18 @@ EXPORT_SYMBOL_GPL(of_property_count_elems_of_size);
*
* @np: device node from which the property value is to be read.
* @propname: name of the property to be searched.
- * @len: requested length of property value
+ * @min: minimum allowed length of property value
+ * @max: maximum allowed length of property value (0 means unlimited)
+ * @len: if !=NULL, actual length is written to here
*
* Search for a property in a device node and valid the requested size.
* Returns the property value on success, -EINVAL if the property does not
* exist, -ENODATA if property does not have a value, and -EOVERFLOW if the
- * property data isn't large enough.
+ * property data is too small or too large.
*
*/
static void *of_find_property_value_of_size(const struct device_node *np,
- const char *propname, u32 len)
+ const char *propname, u32 min, u32 max, size_t *len)
{
struct property *prop = of_find_property(np, propname, NULL);

@@ -1163,9 +1165,14 @@ static void *of_find_property_value_of_size(const struct device_node *np,
return ERR_PTR(-EINVAL);
if (!prop->value)
return ERR_PTR(-ENODATA);
- if (len > prop->length)
+ if (prop->length < min)
+ return ERR_PTR(-EOVERFLOW);
+ if (max && prop->length > max)
return ERR_PTR(-EOVERFLOW);

+ if (len)
+ *len = prop->length;
+
return prop->value;
}

@@ -1189,7 +1196,9 @@ int of_property_read_u32_index(const struct device_node *np,
u32 index, u32 *out_value)
{
const u32 *val = of_find_property_value_of_size(np, propname,
- ((index + 1) * sizeof(*out_value)));
+ ((index + 1) * sizeof(*out_value)),
+ 0,
+ NULL);

if (IS_ERR(val))
return PTR_ERR(val);
@@ -1221,7 +1230,9 @@ int of_property_read_u8_array(const struct device_node *np,
const char *propname, u8 *out_values, size_t sz)
{
const u8 *val = of_find_property_value_of_size(np, propname,
- (sz * sizeof(*out_values)));
+ (sz * sizeof(*out_values)),
+ 0,
+ NULL);

if (IS_ERR(val))
return PTR_ERR(val);
@@ -1254,7 +1265,9 @@ int of_property_read_u16_array(const struct device_node *np,
const char *propname, u16 *out_values, size_t sz)
{
const __be16 *val = of_find_property_value_of_size(np, propname,
- (sz * sizeof(*out_values)));
+ (sz * sizeof(*out_values)),
+ 0,
+ NULL);

if (IS_ERR(val))
return PTR_ERR(val);
@@ -1286,7 +1299,9 @@ int of_property_read_u32_array(const struct device_node *np,
size_t sz)
{
const __be32 *val = of_find_property_value_of_size(np, propname,
- (sz * sizeof(*out_values)));
+ (sz * sizeof(*out_values)),
+ 0,
+ NULL);

if (IS_ERR(val))
return PTR_ERR(val);
@@ -1314,7 +1329,9 @@ int of_property_read_u64(const struct device_node *np, const char *propname,
u64 *out_value)
{
const __be32 *val = of_find_property_value_of_size(np, propname,
- sizeof(*out_value));
+ sizeof(*out_value),
+ 0,
+ NULL);

if (IS_ERR(val))
return PTR_ERR(val);
@@ -1345,7 +1362,9 @@ int of_property_read_u64_array(const struct device_node *np,
size_t sz)
{
const __be32 *val = of_find_property_value_of_size(np, propname,
- (sz * sizeof(*out_values)));
+ (sz * sizeof(*out_values)),
+ 0,
+ NULL);

if (IS_ERR(val))
return PTR_ERR(val);
--
1.9.1