Re: [PATCH for-7.2 04/10] hmp, device_tree.c: introduce fdt-save

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Daniel Henrique Barboza (danielhb413@gmail.com) wrote:
> To save the FDT blob we have the '-machine dumpdtb=<file>' property. With this
> property set, the machine saves the FDT in <file> and exit. The created
> file can then be converted to plain text dts format using 'dtc'.
> 
> There's nothing particularly sophisticated into saving the FDT that
> can't be done with the machine at any state, as long as the machine has
> a valid FDT to be saved.
> 
> The 'fdt-save' command receives a 'filename' paramenter and, if a valid
> FDT is available, it'll save it in a file 'filename'. In short, this is
> a '-machine dumpdtb' that can be fired on demand via HMP.
> 
> A valid FDT consists of a FDT that was created using libfdt being
> retrieved via 'current_machine->fdt' in device_tree.c. This condition is
> met by most FDT users in QEMU.
> 
> Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
> Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>

These all probably should be done as wrappers around qmp equivalents.

Dave

> ---
>  hmp-commands.hx              | 13 +++++++++++++
>  include/sysemu/device_tree.h |  2 ++
>  monitor/misc.c               | 13 +++++++++++++
>  softmmu/device_tree.c        | 18 ++++++++++++++++++
>  4 files changed, 46 insertions(+)
> 
> diff --git a/hmp-commands.hx b/hmp-commands.hx
> index c9d465735a..3c134cf652 100644
> --- a/hmp-commands.hx
> +++ b/hmp-commands.hx
> @@ -1768,3 +1768,16 @@ ERST
>                        "\n\t\t\t -b to specify dirty bitmap as method of calculation)",
>          .cmd        = hmp_calc_dirty_rate,
>      },
> +
> +    {
> +        .name       = "fdt-save",
> +        .args_type  = "filename:s",
> +        .params     = "[filename] file to save the FDT",
> +        .help       = "save the FDT in the 'filename' file to be decoded using dtc",
> +        .cmd        = hmp_fdt_save,
> +    },
> +
> +SRST
> +``fdt-save`` *filename*
> +  Save the FDT in the 'filename' file to be decoded using dtc
> +ERST
> diff --git a/include/sysemu/device_tree.h b/include/sysemu/device_tree.h
> index ef060a9759..1397adb21c 100644
> --- a/include/sysemu/device_tree.h
> +++ b/include/sysemu/device_tree.h
> @@ -123,6 +123,8 @@ 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);
>  
> +void fdt_save(const char *filename, Error **errp);
> +
>  #define qemu_fdt_setprop_cells(fdt, node_path, property, ...)                 \
>      do {                                                                      \
>          uint32_t qdt_tmp[] = { __VA_ARGS__ };                                 \
> diff --git a/monitor/misc.c b/monitor/misc.c
> index 3d2312ba8d..145285cec0 100644
> --- a/monitor/misc.c
> +++ b/monitor/misc.c
> @@ -78,6 +78,7 @@
>  #include "qapi/qmp-event.h"
>  #include "sysemu/cpus.h"
>  #include "qemu/cutils.h"
> +#include "sysemu/device_tree.h"
>  
>  #if defined(TARGET_S390X)
>  #include "hw/s390x/storage-keys.h"
> @@ -936,6 +937,18 @@ static void hmp_boot_set(Monitor *mon, const QDict *qdict)
>      }
>  }
>  
> +static void hmp_fdt_save(Monitor *mon, const QDict *qdict)
> +{
> +    const char *path = qdict_get_str(qdict, "filename");
> +    Error *local_err = NULL;
> +
> +    fdt_save(path, &local_err);
> +
> +    if (local_err) {
> +        error_report_err(local_err);
> +    }
> +}
> +
>  static void hmp_info_mtree(Monitor *mon, const QDict *qdict)
>  {
>      bool flatview = qdict_get_try_bool(qdict, "flatview", false);
> diff --git a/softmmu/device_tree.c b/softmmu/device_tree.c
> index 6ca3fad285..eeab6a5ef0 100644
> --- a/softmmu/device_tree.c
> +++ b/softmmu/device_tree.c
> @@ -643,3 +643,21 @@ out:
>      g_free(propcells);
>      return ret;
>  }
> +
> +void fdt_save(const char *filename, Error **errp)
> +{
> +    int size;
> +
> +    if (!current_machine->fdt) {
> +        error_setg(errp, "Unable to find the machine FDT");
> +        return;
> +    }
> +
> +    size = fdt_totalsize(current_machine->fdt);
> +
> +    if (g_file_set_contents(filename, current_machine->fdt, size, NULL)) {
> +        return;
> +    }
> +
> +    error_setg(errp, "Error when saving machine FDT to file %s", filename);
> +}
> -- 
> 2.36.1
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK