A string array in device tree is simply a series of \0 terminated
strings next to each other. As libfdt doesn't support that directly
we need to build it ourselves.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20201105175153.30489-4-alex.bennee@linaro.org>

---
v2
  - checkpatch long line fix
---
 include/sysemu/device_tree.h | 17 +++++++++++++++++
 softmmu/device_tree.c        | 26 ++++++++++++++++++++++++++
 2 files changed, 43 insertions(+)

diff --git a/include/sysemu/device_tree.h b/include/sysemu/device_tree.h
index 982c89345f..8a2fe55622 100644
--- a/include/sysemu/device_tree.h
+++ b/include/sysemu/device_tree.h
@@ -70,6 +70,23 @@ int qemu_fdt_setprop_u64(void *fdt, const char *node_path,
                          const char *property, uint64_t val);
 int qemu_fdt_setprop_string(void *fdt, const char *node_path,
                             const char *property, const char *string);
+
+/**
+ * qemu_fdt_setprop_string_array: set a string array property
+ *
+ * @fdt: pointer to the dt blob
+ * @name: node name
+ * @prop: property array
+ * @array: pointer to an array of string pointers
+ * @len: length of array
+ *
+ * assigns a string array to a property. This function converts and
+ * array of strings to a sequential string with \0 separators before
+ * setting the property.
+ */
+int qemu_fdt_setprop_string_array(void *fdt, const char *node_path,
+                                  const char *prop, char **array, int len);
+
 int qemu_fdt_setprop_phandle(void *fdt, const char *node_path,
                              const char *property,
                              const char *target_node_path);
diff --git a/softmmu/device_tree.c b/softmmu/device_tree.c
index b9a3ddc518..2691c58cf6 100644
--- a/softmmu/device_tree.c
+++ b/softmmu/device_tree.c
@@ -21,6 +21,7 @@
 #include "qemu/error-report.h"
 #include "qemu/option.h"
 #include "qemu/bswap.h"
+#include "qemu/cutils.h"
 #include "sysemu/device_tree.h"
 #include "sysemu/sysemu.h"
 #include "hw/loader.h"
@@ -397,6 +398,31 @@ int qemu_fdt_setprop_string(void *fdt, const char *node_path,
     return r;
 }
 
+/*
+ * libfdt doesn't allow us to add string arrays directly but they are
+ * test a series of null terminated strings with a length. We build
+ * the string up here so we can calculate the final length.
+ */
+int qemu_fdt_setprop_string_array(void *fdt, const char *node_path,
+                                  const char *prop, char **array, int len)
+{
+    int ret, i, total_len = 0;
+    char *str, *p;
+    for (i = 0; i < len; i++) {
+        total_len += strlen(array[i]) + 1;
+    }
+    p = str = g_malloc0(total_len);
+    for (i = 0; i < len; i++) {
+        int len = strlen(array[i]) + 1;
+        pstrcpy(p, len, array[i]);
+        p += len;
+    }
+
+    ret = qemu_fdt_setprop(fdt, node_path, prop, str, total_len);
+    g_free(str);
+    return ret;
+}
+
 const void *qemu_fdt_getprop(void *fdt, const char *node_path,
                              const char *property, int *lenp, Error **errp)
 {
-- 
2.20.1

On Thu, Feb 11, 2021 at 05:19:41PM +0000, Alex Bennée wrote:
> A string array in device tree is simply a series of \0 terminated
> strings next to each other. As libfdt doesn't support that directly
> we need to build it ourselves.

Hm, that might not make a bad extension to libfdt...

> 
> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
> Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
> Message-Id: <20201105175153.30489-4-alex.bennee@linaro.org>
> 
> ---
> v2
>   - checkpatch long line fix
> ---
>  include/sysemu/device_tree.h | 17 +++++++++++++++++
>  softmmu/device_tree.c        | 26 ++++++++++++++++++++++++++
>  2 files changed, 43 insertions(+)
> 
> diff --git a/include/sysemu/device_tree.h b/include/sysemu/device_tree.h
> index 982c89345f..8a2fe55622 100644
> --- a/include/sysemu/device_tree.h
> +++ b/include/sysemu/device_tree.h
> @@ -70,6 +70,23 @@ int qemu_fdt_setprop_u64(void *fdt, const char *node_path,
>                           const char *property, uint64_t val);
>  int qemu_fdt_setprop_string(void *fdt, const char *node_path,
>                              const char *property, const char *string);
> +
> +/**
> + * qemu_fdt_setprop_string_array: set a string array property
> + *
> + * @fdt: pointer to the dt blob
> + * @name: node name
> + * @prop: property array
> + * @array: pointer to an array of string pointers
> + * @len: length of array
> + *
> + * assigns a string array to a property. This function converts and
> + * array of strings to a sequential string with \0 separators before
> + * setting the property.
> + */
> +int qemu_fdt_setprop_string_array(void *fdt, const char *node_path,
> +                                  const char *prop, char **array, int len);
> +
>  int qemu_fdt_setprop_phandle(void *fdt, const char *node_path,
>                               const char *property,
>                               const char *target_node_path);
> diff --git a/softmmu/device_tree.c b/softmmu/device_tree.c
> index b9a3ddc518..2691c58cf6 100644
> --- a/softmmu/device_tree.c
> +++ b/softmmu/device_tree.c
> @@ -21,6 +21,7 @@
>  #include "qemu/error-report.h"
>  #include "qemu/option.h"
>  #include "qemu/bswap.h"
> +#include "qemu/cutils.h"
>  #include "sysemu/device_tree.h"
>  #include "sysemu/sysemu.h"
>  #include "hw/loader.h"
> @@ -397,6 +398,31 @@ int qemu_fdt_setprop_string(void *fdt, const char *node_path,
>      return r;
>  }
>  
> +/*
> + * libfdt doesn't allow us to add string arrays directly but they are
> + * test a series of null terminated strings with a length. We build
> + * the string up here so we can calculate the final length.
> + */
> +int qemu_fdt_setprop_string_array(void *fdt, const char *node_path,
> +                                  const char *prop, char **array, int len)
> +{
> +    int ret, i, total_len = 0;
> +    char *str, *p;
> +    for (i = 0; i < len; i++) {
> +        total_len += strlen(array[i]) + 1;
> +    }
> +    p = str = g_malloc0(total_len);
> +    for (i = 0; i < len; i++) {
> +        int len = strlen(array[i]) + 1;
> +        pstrcpy(p, len, array[i]);
> +        p += len;
> +    }
> +
> +    ret = qemu_fdt_setprop(fdt, node_path, prop, str, total_len);
> +    g_free(str);
> +    return ret;
> +}
> +
>  const void *qemu_fdt_getprop(void *fdt, const char *node_path,
>                               const char *property, int *lenp, Error **errp)
>  {

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson