Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752759AbaBSIQu (ORCPT ); Wed, 19 Feb 2014 03:16:50 -0500 Received: from mail-pd0-f172.google.com ([209.85.192.172]:56705 "EHLO mail-pd0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752712AbaBSIQs (ORCPT ); Wed, 19 Feb 2014 03:16:48 -0500 From: Kevin Hao To: devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Kevin Hao , Rob Herring , Sebastian Hesselbarth , Grant Likely Subject: [PATCH v3 2/4] of: reimplement the matching method for __of_match_node() Date: Wed, 19 Feb 2014 16:15:45 +0800 Message-Id: <1392797745-7561-1-git-send-email-haokexin@gmail.com> X-Mailer: git-send-email 1.8.5.3 In-Reply-To: <20140219075812.GE14031@pek-khao-d1.corp.ad.wrs.com> References: <20140219075812.GE14031@pek-khao-d1.corp.ad.wrs.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 [grant.likely: Changed multiplier to 4 which makes more sense] Signed-off-by: Grant Likely --- 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", }, {} }; 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) { const char* cp; int cplen, l; + int score = 0; cp = __of_get_property(device, "compatible", &cplen); if (cp == NULL) return 0; while (cplen > 0) { - if (of_compat_cmp(cp, compat, strlen(compat)) == 0) + score++; + if (of_compat_cmp(cp, compat, strlen(compat)) == 0) { + if (pscore) + *pscore = score; return 1; + } l = strlen(cp) + 1; cp += l; cplen -= l; @@ -368,6 +375,15 @@ static int __of_device_is_compatible(const struct device_node *device, /** Checks if the given "compat" string matches one of the strings in * the device's "compatible" property */ +static int __of_device_is_compatible(const struct device_node *device, + const char *compat) +{ + return __of_device_is_compatible_score(device, compat, NULL); +} + +/** Checks if the given "compat" string matches one of the strings in + * the device's "compatible" property + */ int of_device_is_compatible(const struct device_node *device, const char *compat) { @@ -734,25 +750,55 @@ static const struct of_device_id *__of_match_node(const struct of_device_id *matches, const struct device_node *node) { + const struct of_device_id *best_match = NULL; + int best_score = 0; + 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; + int score = 0; + + /* + * Matching compatible is better than matching type and name, + * and the specific compatible is better than the general. + */ + if (matches->compatible[0]) { + if (__of_device_is_compatible_score(node, + matches->compatible, &score)) + score = INT_MAX - 4 * score; + else + score = INT_MIN; + } + + /* + * Matching type is better than matching name, but matching + * both is even better than that. + */ + if (matches->type[0]) { + if (node->type && !strcmp(matches->type, node->type)) + score += 2; + else + score = INT_MIN; + } + + /* Matching name is a bit better than not */ + if (matches->name[0]) { + if (node->name && !strcmp(matches->name, node->name)) + score++; + else + score = INT_MIN; + } + + if (score > best_score) { + best_match = matches; + best_score = score; + } + matches++; } - return NULL; + + return best_match; } /** @@ -760,7 +806,19 @@ 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. The priority order + * for the matching is: + * 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 */ const struct of_device_id *of_match_node(const struct of_device_id *matches, const struct device_node *node) -- 1.8.5.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/