From: Thierry Reding <tred...@nvidia.com>
The fdt_get_max_phandle() function has some shortcomings. On one hand
it returns just a uint32_t which means to check for the "negative"
error code a caller has to explicitly check against the error code
(uint32_t)-1. In addition, the -1 is the only error code that can be
returned, so a caller cannot tell the difference between the various
failures.
Fix this by adding a new fdt_find_max_phandle() function that returns an
error code on failure and 0 on success, just like other APIs, and stores
the maximum phandle value in an output argument on success.
This also refactors fdt_get_max_phandle() to use the new function. Add a
note pointing out that the new fdt_find_max_phandle() function should be
preferred over fdt_get_max_phandle().
Signed-off-by: Thierry Reding <tred...@nvidia.com>
Message-Id: <20190326153302.17109-1-thierry.red...@gmail.com>
[dwg: Reword for some inaccuracies in the commit message]
Signed-off-by: David Gibson <da...@gibson.dropbear.id.au>
---
cpukit/dtc/libfdt/fdt_ro.c | 44 +++++++++++++++++++++++++++++---------------
cpukit/include/libfdt.h | 16 ++++++++++++++++
cpukit/include/libfdt_env.h | 1 +
3 files changed, 46 insertions(+), 15 deletions(-)
diff --git a/cpukit/dtc/libfdt/fdt_ro.c b/cpukit/dtc/libfdt/fdt_ro.c
index eafc142828..1d0335ee71 100644
--- a/cpukit/dtc/libfdt/fdt_ro.c
+++ b/cpukit/dtc/libfdt/fdt_ro.c
@@ -144,32 +144,46 @@ static int fdt_string_eq_(const void *fdt, int stroffset,
return p && (slen == len) && (memcmp(p, s, len) == 0);
}
-uint32_t fdt_get_max_phandle(const void *fdt)
+int fdt_find_max_phandle(const void *fdt, uint32_t *phandle)
{
- uint32_t max_phandle = 0;
- int offset;
+ uint32_t max = 0;
+ int offset = -1;
- for (offset = fdt_next_node(fdt, -1, NULL);;
- offset = fdt_next_node(fdt, offset, NULL)) {
- uint32_t phandle;
+ while (true) {
+ uint32_t value;
- if (offset == -FDT_ERR_NOTFOUND)
- return max_phandle;
+ offset = fdt_next_node(fdt, offset, NULL);
+ if (offset < 0) {
+ if (offset == -FDT_ERR_NOTFOUND)
+ break;
- if (offset < 0)
- return (uint32_t)-1;
+ return offset;
+ }
- phandle = fdt_get_phandle(fdt, offset);
- if (phandle == (uint32_t)-1)
- continue;
+ value = fdt_get_phandle(fdt, offset);
- if (phandle > max_phandle)
- max_phandle = phandle;
+ if (value > max)
+ max = value;
}
+ if (phandle)
+ *phandle = max;
+
return 0;
}
+uint32_t fdt_get_max_phandle(const void *fdt)
+{
+ uint32_t phandle;
+ int err;
+
+ err = fdt_find_max_phandle(fdt, &phandle);
+ if (err < 0)
+ return (uint32_t)-1;
+
+ return phandle;
+}
+
static const struct fdt_reserve_entry *fdt_mem_rsv(const void *fdt, int n)
{
int offset = n * sizeof(struct fdt_reserve_entry);
diff --git a/cpukit/include/libfdt.h b/cpukit/include/libfdt.h
index e70f5bf7e8..e1498c3c21 100644
--- a/cpukit/include/libfdt.h
+++ b/cpukit/include/libfdt.h
@@ -385,6 +385,20 @@ const char *fdt_get_string(const void *fdt, int stroffset,
int *lenp);
*/
const char *fdt_string(const void *fdt, int stroffset);
+/**
+ * fdt_find_max_phandle - find and return the highest phandle in a tree
+ * @fdt: pointer to the device tree blob
+ * @phandle: return location for the highest phandle value found in the tree
+ *
+ * fdt_find_max_phandle() finds the highest phandle value in the given device
+ * tree. The value returned in @phandle is only valid if the function returns
+ * success.
+ *
+ * returns:
+ * 0 on success or a negative error code on failure
+ */
+int fdt_find_max_phandle(const void *fdt, uint32_t *phandle);
+
/**
* fdt_get_max_phandle - retrieves the highest phandle in a tree
* @fdt: pointer to the device tree blob
@@ -393,6 +407,8 @@ const char *fdt_string(const void *fdt, int stroffset);
* device tree. This will ignore badly formatted phandles, or phandles
* with a value of 0 or -1.
*
+ * This function is deprecated in favour of fdt_find_max_phandle().
+ *
* returns:
* the highest phandle on success
* 0, if no phandle was found in the device tree
diff --git a/cpukit/include/libfdt_env.h b/cpukit/include/libfdt_env.h
index eb2053845c..4d1cdfa585 100644
--- a/cpukit/include/libfdt_env.h
+++ b/cpukit/include/libfdt_env.h
@@ -52,6 +52,7 @@
* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
+#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
--
2.16.4
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