Re: [RFC PATCH v3 2/9] device_tree: Add qemu_fdt_add_path

[David Gibson]

On Sun, May 16, 2021 at 06:28:53PM +0800, Yanan Wang wrote:
> From: Andrew Jones <drjones@redhat.com>
> 
> qemu_fdt_add_path() works like qemu_fdt_add_subnode(), except it
> also adds all missing subnodes from the given path. We'll use it
> in a coming patch where we will add cpu-map to the device tree.
> 
> And we also tweak an error message of qemu_fdt_add_subnode().
> 
> Cc: David Gibson <david@gibson.dropbear.id.au>
> Cc: Alistair Francis <alistair.francis@wdc.com>
> Signed-off-by: Andrew Jones <drjones@redhat.com>
> Co-developed-by: Yanan Wang <wangyanan55@huawei.com>
> Signed-off-by: Yanan Wang <wangyanan55@huawei.com>

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

Wonder if I should integrate a function like this into libfdt.

> ---
>  include/sysemu/device_tree.h |  1 +
>  softmmu/device_tree.c        | 44 ++++++++++++++++++++++++++++++++++--
>  2 files changed, 43 insertions(+), 2 deletions(-)
> 
> diff --git a/include/sysemu/device_tree.h b/include/sysemu/device_tree.h
> index 8a2fe55622..ef060a9759 100644
> --- a/include/sysemu/device_tree.h
> +++ b/include/sysemu/device_tree.h
> @@ -121,6 +121,7 @@ uint32_t qemu_fdt_get_phandle(void *fdt, const char 
> *path);
>  uint32_t qemu_fdt_alloc_phandle(void *fdt);
>  int qemu_fdt_nop_node(void *fdt, const char *node_path);
>  int qemu_fdt_add_subnode(void *fdt, const char *name);
> +int qemu_fdt_add_path(void *fdt, const char *path);
>  
>  #define qemu_fdt_setprop_cells(fdt, node_path, property, ...)                
>  \
>      do {                                                                     
>  \
> diff --git a/softmmu/device_tree.c b/softmmu/device_tree.c
> index b621f63fba..3965c834ca 100644
> --- a/softmmu/device_tree.c
> +++ b/softmmu/device_tree.c
> @@ -540,8 +540,8 @@ int qemu_fdt_add_subnode(void *fdt, const char *name)
>  
>      retval = fdt_add_subnode(fdt, parent, basename);
>      if (retval < 0) {
> -        error_report("FDT: Failed to create subnode %s: %s", name,
> -                     fdt_strerror(retval));
> +        error_report("%s: Failed to create subnode %s: %s",
> +                     __func__, name, fdt_strerror(retval));
>          exit(1);
>      }
>  
> @@ -549,6 +549,46 @@ int qemu_fdt_add_subnode(void *fdt, const char *name)
>      return retval;
>  }
>  
> +/*
> + * qemu_fdt_add_path: Like qemu_fdt_add_subnode(), but will add
> + * all missing subnodes from the given path.
> + */
> +int qemu_fdt_add_path(void *fdt, const char *path)
> +{
> +    const char *name;
> +    const char *p = path;
> +    int namelen, retval;
> +    int parent = 0;
> +
> +    if (path[0] != '/') {
> +        return -1;
> +    }
> +
> +    while (p) {
> +        name = p + 1;
> +        p = strchr(name, '/');
> +        namelen = p != NULL ? p - name : strlen(name);
> +
> +        retval = fdt_subnode_offset_namelen(fdt, parent, name, namelen);
> +        if (retval < 0 && retval != -FDT_ERR_NOTFOUND) {
> +            error_report("%s: Unexpected error in finding subnode %.*s: %s",
> +                         __func__, namelen, name, fdt_strerror(retval));
> +            exit(1);
> +        } else if (retval == -FDT_ERR_NOTFOUND) {
> +            retval = fdt_add_subnode_namelen(fdt, parent, name, namelen);
> +            if (retval < 0) {
> +                error_report("%s: Failed to create subnode %.*s: %s",
> +                             __func__, namelen, name, fdt_strerror(retval));
> +                exit(1);
> +            }
> +        }
> +
> +        parent = retval;
> +    }
> +
> +    return retval;
> +}
> +
>  void qemu_fdt_dumpdtb(void *fdt, int size)
>  {
>      const char *dumpdtb = current_machine->dumpdtb;

-- 
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

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