Re: [Xen-devel] [RFC 15/24] xen/arm: Use dt_device_match to avoid multiple if conditions

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Fri, 2013-08-16 at 22:05 +0100, Julien Grall wrote:
> There is some place in Xen ARM code where multiple if conditions is used
> check the presence of a node or find a node.
> These pieces of code can be replace by an array and using proper device tree
> helpers.
> 
> Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
> ---
>  xen/arch/arm/domain_build.c |   12 +++++++++---
>  xen/arch/arm/time.c         |   11 ++++++++---
>  2 files changed, 17 insertions(+), 6 deletions(-)
> 
> diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
> index a324c3b..604ec1c 100644
> --- a/xen/arch/arm/domain_build.c
> +++ b/xen/arch/arm/domain_build.c
> @@ -435,6 +435,14 @@ static int map_device(struct domain *d, const struct 
> dt_device_node *dev)
>      return 0;
>  }
>  
> +static const struct dt_device_match skip_matches[] __initconst =
> +{
> +    DT_MATCH_COMPATIBLE("xen,xen"),
> +    DT_MATCH_TYPE("memory"),
> +    DT_MATCH_PATH("/chosen"),
> +    { /* sentinel */ },
> +};

Can this not be within the scope of the only function which uses it?

If not then perhaps it can be given a more meaningful name.
dom0_skip_matches?

> +
>  static int handle_node(struct domain *d, const struct dt_device_node *np)
>  {
>      const struct dt_device_node *child;
> @@ -443,9 +451,7 @@ static int handle_node(struct domain *d, const struct 
> dt_device_node *np)
>      DPRINT("handle %s\n", dt_node_full_name(np));
>  
>      /* Skip theses nodes and the sub-nodes */
> -    if ( dt_device_is_compatible(np, "xen,xen") ||
> -         dt_device_type_is_equal(np, "memory") ||
> -         !strcmp("/chosen", dt_node_full_name(np)) )
> +    if ( dt_match_node(skip_matches, np ) )
>          return 0;
>  
>      if ( dt_device_used_by(np) != DOMID_XEN )
> diff --git a/xen/arch/arm/time.c b/xen/arch/arm/time.c
> index b5864ef..05e58ba 100644
> --- a/xen/arch/arm/time.c
> +++ b/xen/arch/arm/time.c
> @@ -98,6 +98,13 @@ static uint32_t calibrate_timer(void)
>  }
>  */
>  
> +static const struct dt_device_match timer_ids[] __initdata =
> +{
> +    DT_MATCH_COMPATIBLE("arm,armv7-timer"),
> +    DT_MATCH_COMPATIBLE("arm,armv8-timer"),
> +    { /* sentinel */ },
> +};
> +
>  /* Set up the timer on the boot CPU */
>  int __init init_xen_time(void)
>  {
> @@ -105,9 +112,7 @@ int __init init_xen_time(void)
>      int res;
>      unsigned int i;
>  
> -    dev = dt_find_compatible_node(NULL, NULL, "arm,armv7-timer");
> -    if ( !dev )
> -        dev = dt_find_compatible_node(NULL, NULL, "arm,armv8-timer");
> +    dev = dt_find_matching_node(NULL, timer_ids);
>      if ( !dev )
>          panic("Unable to find a compatible timer in the device tree\n");
>  



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