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Message-ID: <529E614B.3070307@gmail.com>
Date: Tue, 03 Dec 2013 23:55:07 +0100
From: Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>
To: Meelis Roos <mroos@...ux.ee>
CC: Grant Likely <grant.likely@...aro.org>,
Rob Herring <rob.herring@...xeda.com>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Russell King <linux@....linux.org.uk>,
Thierry Reding <thierry.reding@...il.com>,
Marc Kleine-Budde <mkl@...gutronix.de>,
Scott Wood <scottwood@...escale.com>,
devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
Linux Kernel list <linux-kernel@...r.kernel.org>,
David Miller <davem@...emloft.net>
Subject: Re: [PATCH v2] OF: base: match each node compatible against all given
matches first
On 12/03/2013 09:14 PM, Meelis Roos wrote:
>> Currently, of_match_node compares each given match against all 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, this patch modifies of_match_node to match each of the node's
>> compatible strings against all given matches first, before checking the
>> next compatible string. This implies that node's compatibles are ordered
>> from specific to generic while given matches can be in any order.
>
> I think I am on the CC: list because of a CPU detection problem report
> on sparc64 (183912d352a242a276a7877852f107459a13aff9 (of: move
> of_get_cpu_node implementation to DT core library) caused trouble and
The reason you are on Cc is that Thierry added you on last patch
version. I cannot see how above commit should be related with this
one, but maybe Thierry can comment on it.
> was reverted). So while your V2 patch does not cause any visible harm on
> the same Sun E3500, my gut feeling is that an additional patch would be
> needed to actually test it (a patch like
> 183912d352a242a276a7877852f107459a13aff9).
This patch deals with matching a node with more than one compatible
string on a (unordered) list of matches. Although not related to your
issue, it is good to hear that it causes no harm on DT-mature archs :)
I tested it with ARM and l2x0 cache controllers, where the specific
of_device_id (marvell,tauros3-cache) is sorted after the generic
one (arm,pl310-cache). The corresponding node's property is
compatible = "marvell,tauros3-cache", "arm,pl310-cache".
Without this patch, of_match_node always hits the first match that
equals _any_ of the above compatible strings. With this patch, it
hits the matches _in order_ of the compatible strings.
> Is this correct or am I missing something?
Thierry?
>> Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>
>> ---
>> Changelog:
>> v1->v2:
>> - Allow checks against nodes with no compatible (Reported by Rob Herring)
>> - Add some comments
>>
>> Cc: Grant Likely <grant.likely@...aro.org>
>> Cc: Rob Herring <rob.herring@...xeda.com>
>> Cc: Benjamin Herrenschmidt <benh@...nel.crashing.org>
>> Cc: Russell King <linux@....linux.org.uk>
>> Cc: Thierry Reding <thierry.reding@...il.com>
>> Cc: Meelis Roos <mroos@...ux.ee>
>> Cc: Marc Kleine-Budde <mkl@...gutronix.de>
>> Cc: Scott Wood <scottwood@...escale.com>
>> Cc: devicetree@...r.kernel.org
>> Cc: linux-arm-kernel@...ts.infradead.org
>> Cc: linux-kernel@...r.kernel.org
>> ---
>> drivers/of/base.c | 53 +++++++++++++++++++++++++++++++++++++----------------
>> 1 files changed, 37 insertions(+), 16 deletions(-)
>>
>> diff --git a/drivers/of/base.c b/drivers/of/base.c
>> index f807d0e..8d007d8 100644
>> --- a/drivers/of/base.c
>> +++ b/drivers/of/base.c
>> @@ -731,24 +731,42 @@ static
>> const struct of_device_id *__of_match_node(const struct of_device_id *matches,
>> const struct device_node *node)
>> {
>> + const char *cp;
>> + int cplen, l;
>> +
>> if (!matches)
>> return NULL;
>>
>> - while (matches->name[0] || matches->type[0] || matches->compatible[0]) {
>> - int match = 1;
>> - if (matches->name[0])
>> - match &= node->name
>> - && !strcmp(matches->name, node->name);
>> - if (matches->type[0])
>> - match &= node->type
>> - && !strcmp(matches->type, node->type);
>> - if (matches->compatible[0])
>> - match &= __of_device_is_compatible(node,
>> - matches->compatible);
>> - if (match)
>> - return matches;
>> - matches++;
>> - }
>> + cp = __of_get_property(node, "compatible", &cplen);
>> + do {
>> + const struct of_device_id *m = matches;
>> +
>> + /* Check against matches with current compatible string */
>> + while (m->name[0] || m->type[0] || m->compatible[0]) {
>> + int match = 1;
>> + if (m->name[0])
>> + match &= node->name
>> + && !strcmp(m->name, node->name);
>> + if (m->type[0])
>> + match &= node->type
>> + && !strcmp(m->type, node->type);
>> + if (m->compatible[0])
>> + match &= cp
>> + && !of_compat_cmp(m->compatible, cp,
>> + strlen(m->compatible));
>> + if (match)
>> + return m;
>> + m++;
>> + }
>> +
>> + /* Get node's next compatible string */
>> + if (cp) {
>> + l = strlen(cp) + 1;
>> + cp += l;
>> + cplen -= l;
>> + }
>> + } while (cp && (cplen > 0));
>> +
>> return NULL;
>> }
>>
>> @@ -757,7 +775,10 @@ const struct of_device_id *__of_match_node(const struct of_device_id *matches,
>> * @matches: array of of device match structures to search in
>> * @node: the of device structure to match against
>> *
>> - * Low level utility function used by device matching.
>> + * Low level utility function used by device matching. Matching order
>> + * is to compare each of the node's compatibles with all given matches
>> + * first. This implies node's compatible is sorted from specific to
>> + * generic while matches can be in any order.
>> */
>> const struct of_device_id *of_match_node(const struct of_device_id *matches,
>> const struct device_node *node)
>>
>
--
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