On 5/28/21 7:58 PM, Atish Patra wrote:

On Fri, May 28, 2021 at 10:06 AM Heinrich Schuchardt [off-list ref] wrote:

quoted

The value of the /chosen/stdout-path devicetree property is used to
determine the UART used by openSBI. According to the devicetree
specification the value may contain a hyphen, e.g.

         chosen {
                 stdout-path = "/serial at f00:115200";
         };

If the character ':' is present, it terminates the path of the device.

Signed-off-by: Heinrich Schuchardt <redacted>
---
v3:
         * Use fdt_path_offset_namelen() if stdout-path contains a ':'
           (thanks Atish).
         * Fix typo %s/pointed/pointed to/.
---
  lib/utils/serial/fdt_serial.c | 15 ++++++++++++---
  1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/lib/utils/serial/fdt_serial.c b/lib/utils/serial/fdt_serial.c
index 25982ec..1d1eba8 100644
--- a/lib/utils/serial/fdt_serial.c
+++ b/lib/utils/serial/fdt_serial.c

@@ -42,12 +42,21 @@ int fdt_serial_init(void)
         int pos, noff = -1, len, coff, rc;
         void *fdt = sbi_scratch_thishart_arg1_ptr();

-       /* Find offset of node pointed by stdout-path */
+       /* Find offset of node pointed to by stdout-path */
         coff = fdt_path_offset(fdt, "/chosen");
         if (-1 < coff) {
                 prop = fdt_getprop(fdt, coff, "stdout-path", &len);
-               if (prop && len)
-                       noff = fdt_path_offset(fdt, prop);
+               if (prop && len) {
+                       const char *sep, *start = prop;
+
+                       /* The device path may be followed by ':' */
+                       sep = strchr(start, ':');
+                       if (sep)
+                               noff = fdt_path_offset_namelen(fdt, prop,
+                                                              sep - start);
+                       else
+                               noff = fdt_path_offset(fdt, prop);

We can further simplify this by passing strlen() to
fdt_path_offset_namelen if ": "
is not present. But that's just personal preference.

Calling fdt_path_offset_namelen() with strlen() is what
fdt_path_offset() is actually doing.

The code above results in the smaller code size and is well readable.

Thank you for reviewing.

Best regards

Heinrich

I am fine with this version as well.

quoted

+               }
         }

         /* First check DT node pointed by stdout-path */
--
2.30.2

Either way,

Reviewed-by: Atish Patra <redacted>