From patchwork Mon Dec 2 11:02:20 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hiroshi Doyu X-Patchwork-Id: 295884 X-Patchwork-Delegate: swarren@nvidia.com Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 9E5A42C009D for ; Mon, 2 Dec 2013 22:02:52 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753472Ab3LBLCv (ORCPT ); Mon, 2 Dec 2013 06:02:51 -0500 Received: from hqemgate16.nvidia.com ([216.228.121.65]:3785 "EHLO hqemgate16.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751284Ab3LBLCt convert rfc822-to-8bit (ORCPT ); Mon, 2 Dec 2013 06:02:49 -0500 Received: from hqnvupgp07.nvidia.com (Not Verified[216.228.121.13]) by hqemgate16.nvidia.com id ; Mon, 02 Dec 2013 03:03:03 -0800 Received: from hqemhub01.nvidia.com ([172.20.12.94]) by hqnvupgp07.nvidia.com (PGP Universal service); Mon, 02 Dec 2013 02:59:59 -0800 X-PGP-Universal: processed; by hqnvupgp07.nvidia.com on Mon, 02 Dec 2013 02:59:59 -0800 Received: from HQMAIL104.nvidia.com (172.18.146.11) by hqemhub01.nvidia.com (172.20.150.30) with Microsoft SMTP Server (TLS) id 8.3.327.1; Mon, 2 Dec 2013 03:02:49 -0800 Received: from HQMAIL104.nvidia.com (172.18.146.11) by HQMAIL104.nvidia.com (172.18.146.11) with Microsoft SMTP Server (TLS) id 15.0.712.24; Mon, 2 Dec 2013 03:02:29 -0800 Received: from deemhub02.nvidia.com (10.21.69.138) by HQMAIL104.nvidia.com (172.18.146.11) with Microsoft SMTP Server (TLS) id 15.0.712.24 via Frontend Transport; Mon, 2 Dec 2013 03:02:29 -0800 Received: from DEMAIL01.nvidia.com ([10.21.69.139]) by deemhub02.nvidia.com ([10.21.69.138]) with mapi; Mon, 2 Dec 2013 12:02:27 +0100 From: Hiroshi Doyu To: "swarren@wwwdotorg.org" CC: "grant.likely@linaro.org" , "thierry.reding@gmail.com" , "robherring2@gmail.com" , "joro@8bytes.org" , Stephen Warren , "will.deacon@arm.com" , "mark.rutland@arm.com" , "devicetree@vger.kernel.org" , "iommu@lists.linux-foundation.org" , "linux-tegra@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "lorenzo.pieralisi@arm.com" , "galak@codeaurora.org" , "linux-kernel@vger.kernel.org" Date: Mon, 2 Dec 2013 12:02:20 +0100 Subject: Re: [RFC][PATCHv6+++ 01/13] of: introduce of_property_for_earch_phandle_with_args() Thread-Topic: [RFC][PATCHv6+++ 01/13] of: introduce of_property_for_earch_phandle_with_args() Thread-Index: Ac7vTfwxH42xXu3UTSWJNuMwLYxJJA== Message-ID: <20131202.130220.1404999403649937134.hdoyu@nvidia.com> References: <20131128.145818.1345100874304396564.hdoyu@nvidia.com><20131129.134625.431945240074254704.hdoyu@nvidia.com><529B8739.60701@wwwdotorg.org> In-Reply-To: <529B8739.60701@wwwdotorg.org> Accept-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-nvconfidentiality: public acceptlanguage: en-US MIME-Version: 1.0 Sender: linux-tegra-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-tegra@vger.kernel.org Stephen Warren wrote @ Sun, 1 Dec 2013 20:00:09 +0100: > On 11/29/2013 04:46 AM, Hiroshi Doyu wrote: > ... > > Iterating over a property containing a list of phandles with arguments > > is a common operation for device drivers. This patch adds a new > > of_property_for_each_phandle_with_args() macro to make the iteration > > simpler. > > > > Introduced a new struct "of_phandle_iter" to keep the state when > > iterating over the list. > > > > Signed-off-by: Hiroshi Doyu > > --- > > v6+++: > > Surely that's v9; "+++" is rather unusual. My intention was to put this into the next v7 series after I get this reviewed as RFC. ... > Together with removing: > > > + const char *cells_name; > > + int cell_count; > > ... then you'd only be left with cur/end, so I think you could get away > without a struct at all, but simply "cur" as the iterator variable, plus > "end" as the one temp variable. Although the above proposal would be alsmot same as "[RFC][PATCHv6++ 01/13]"(*1) where I use *list(cur) and rem as remaining count, here's the update. I'll put this into v7 series. ---8<------8<------8<------8<------8<------8<------8<------8<------8<--- From: Hiroshi Doyu Iterating over a property containing a list of phandles with arguments is a common operation for device drivers. This patch adds a new of_property_for_each_phandle_with_args() macro to make the iteration simpler. Signed-off-by: Hiroshi Doyu --- v6++++: Iterate without intrducing a new struct. v6+++: Introduced a new struct "of_phandle_iter" to keep the state when iterating over the list. v6++: Optimized to avoid O(n^2), suggested by Stephen Warren. http://lists.linuxfoundation.org/pipermail/iommu/2013-November/007066.html I didn't introduce any struct to hold params and state here. v6+: Use the description, which Grant Likely proposed, to be full enough that a future reader can figure out why a patch was written. v5: New patch for v5. Signed-off-by: Hiroshi Doyu --- drivers/of/base.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/of.h | 34 ++++++++++++++++++++++++++++++++++ 2 files changed, 87 insertions(+) diff --git a/drivers/of/base.c b/drivers/of/base.c index f807d0e..7501f24 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -1201,6 +1201,59 @@ void of_print_phandle_args(const char *msg, const struct of_phandle_args *args) printk("\n"); } +const __be32 *of_phandle_iter_next(const char *cells_name, int cell_count, + const __be32 *cur, const __be32 *end, + struct of_phandle_args *out_args) +{ + phandle phandle; + struct device_node *dn; + int i; + + if (!cells_name && !cell_count) + return NULL; + + if (!cur) + return NULL; + + if (end - cur <= 0) + return NULL; + + phandle = be32_to_cpup(cur++); + if (!phandle) + return NULL; + + dn = of_find_node_by_phandle(phandle); + if (!dn) + return NULL; + + if (cells_name) + if (of_property_read_u32(dn, cells_name, &cell_count)) + return NULL; + + out_args->np = dn; + out_args->args_count = cell_count; + for (i = 0; i < cell_count; i++) + out_args->args[i] = be32_to_cpup(cur++); + + return cur; +} +EXPORT_SYMBOL_GPL(of_phandle_iter_next); + +const __be32 *of_phandle_iter_init(const struct device_node *np, + const char *list_name, + const __be32 **end) +{ + size_t bytes; + const __be32 *cur; + + cur = of_get_property(np, list_name, &bytes); + if (bytes) + *end = cur + bytes / sizeof(*cur); + + return cur; +} +EXPORT_SYMBOL_GPL(of_phandle_iter_init); + static int __of_parse_phandle_with_args(const struct device_node *np, const char *list_name, const char *cells_name, diff --git a/include/linux/of.h b/include/linux/of.h index 276c546..c23710b 100644 --- a/include/linux/of.h +++ b/include/linux/of.h @@ -303,6 +303,14 @@ extern int of_parse_phandle_with_fixed_args(const struct device_node *np, extern int of_count_phandle_with_args(const struct device_node *np, const char *list_name, const char *cells_name); +extern const __be32 *of_phandle_iter_init(const struct device_node *np, + const char *list_name, + const __be32 **end); +extern const __be32 *of_phandle_iter_next(const char *cells_name, + int cell_count, + const __be32 *cur, const __be32 *end, + struct of_phandle_args *out_args); + extern void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align)); extern int of_alias_get_id(struct device_node *np, const char *stem); @@ -527,6 +535,24 @@ static inline int of_count_phandle_with_args(struct device_node *np, return -ENOSYS; } +static inline const __be32 *of_phandle_iter_init(const struct device_node *np, + const char *list_name, + const char *cells_name, + const int cell_count, + struct of_phandle_args *out_args) +{ + return NULL; +} + +static inline const __be32 *of_phandle_iter_next(const char *cells_name, + int cell_count, + const __be32 *cur, + const __be32 *end, + struct of_phandle_args *out_args); +{ + return NULL; +} + static inline int of_alias_get_id(struct device_node *np, const char *stem) { return -ENOSYS; @@ -613,6 +639,14 @@ static inline int of_property_read_u32(const struct device_node *np, s; \ s = of_prop_next_string(prop, s)) +#define of_property_for_each_phandle_with_args(node, list_name, cells_name, \ + cell_count, out_args, cur, end) \ + for (cur = of_phandle_iter_init(node, list_name, &end), \ + cur = of_phandle_iter_next(cells_name, cell_count, \ + cur, end, &out_args); \ + cur; \ + cur = of_phandle_iter_next(cells_name, cell_count, cur, end, &out_args)) + #if defined(CONFIG_PROC_FS) && defined(CONFIG_PROC_DEVICETREE) extern void proc_device_tree_add_node(struct device_node *, struct proc_dir_entry *); extern void proc_device_tree_add_prop(struct proc_dir_entry *pde, struct property *prop);