On Wed, 19 Feb 2014 16:15:45 +0800, Kevin Hao <haokexin@xxxxxxxxx> wrote:
> In the current implementation of __of_match_node(), it will compare
> each given match entry against all the node's compatible strings
> with of_device_is_compatible().
>
> To achieve multiple compatible strings per node with ordering from
> specific to generic, this requires given matches to be ordered from
> specific to generic. For most of the drivers this is not true and
> also an alphabetical ordering is more sane there.
>
> Therefore, we define a following priority order for the match, and
> then scan all the entries to find the best match.
> 1. specific compatible && type && name
> 2. specific compatible && type
> 3. specific compatible && name
> 4. specific compatible
> 5. general compatible && type && name
> 6. general compatible && type
> 7. general compatible && name
> 8. general compatible
> 9. type && name
> 10. type
> 11. name
>
> This is based on some pseudo-codes provided by Grant Likely.
>
> Signed-off-by: Kevin Hao <haokexin@xxxxxxxxx>
> [grant.likely: Changed multiplier to 4 which makes more sense]
> Signed-off-by: Grant Likely <grant.likely@xxxxxxxxxx>
> ---
> v3: Also need to bail out when there does have a compatible member in match
> entry, but it doesn't match with the device node's compatible.
>
> v2: Fix the bug such as we get the same score for the following two match
> entries:
> name2 { }
>
> struct of_device_id matches[] = {
> {.name = "name2", },
> {.name = "name2", .type = "type1", },
> {}
> };
BTW, I prefer patch version information like the above to appear before
the '---' line so that it shows up in the final commit log. It is often
useful to have the revision history in mainline.
>
> drivers/of/base.c | 96 ++++++++++++++++++++++++++++++++++++++++++++-----------
> 1 file changed, 77 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/of/base.c b/drivers/of/base.c
> index ba195fbce4c6..8f79f006d86f 100644
> --- a/drivers/of/base.c
> +++ b/drivers/of/base.c
> @@ -342,21 +342,28 @@ struct device_node *of_get_cpu_node(int cpu, unsigned int *thread)
> }
> EXPORT_SYMBOL(of_get_cpu_node);
>
> -/** Checks if the given "compat" string matches one of the strings in
> - * the device's "compatible" property
> +/*
> + * Compare with the __of_device_is_compatible, this will return a score for the
> + * matching strings. The smaller value indicates the match for the more specific
> + * compatible string.
> */
> -static int __of_device_is_compatible(const struct device_node *device,
> - const char *compat)
> +static int __of_device_is_compatible_score(const struct device_node *device,
> + const char *compat, int *pscore)
> {
Another note: I've removed this new function. There are only three users
of __of_device_is_compatible, and they are all in this file. Adding a
field is just fine. I'm also considering rolling the name and
device_type checks into this function, but that goes beyond the bug fix
so it will wait until the next merge window.
g.
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