From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751319AbdAMJIZ (ORCPT ); Fri, 13 Jan 2017 04:08:25 -0500 Received: from szxga01-in.huawei.com ([58.251.152.64]:7338 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751284AbdAMJIX (ORCPT ); Fri, 13 Jan 2017 04:08:23 -0500 Subject: Re: [PATCH v2 1/2] of: base: add support to find the level of the last cache To: Sudeep Holla , References: <1484245772-31511-1-git-send-email-sudeep.holla@arm.com> CC: Rob Herring , Catalin Marinas , Will Deacon , , , Mark Rutland From: Tan Xiaojun Message-ID: <58789877.1010705@huawei.com> Date: Fri, 13 Jan 2017 17:05:59 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <1484245772-31511-1-git-send-email-sudeep.holla@arm.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.21.79] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020202.58789880.0109,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-06-18 04:22:30, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: aa765d821d16bdc270d07faa30f42ea7 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2017/1/13 2:29, Sudeep Holla wrote: > It is useful to have helper function just to get the number of cache > levels for a given logical cpu. We can obtain the same by just checking > the level at which the last cache is present. This patch adds support > to find the level of the last cache for a given cpu. > > It will be used on ARM64 platform where the device tree provides the > information for the additional non-architected/transparent/external > last level caches that are not integrated with the processors. > > Suggested-by: Rob Herring > Cc: Rob Herring > Cc: Mark Rutland > Signed-off-by: Sudeep Holla Tested-by: Tan Xiaojun > --- > drivers/of/base.c | 27 +++++++++++++++++++++++++++ > include/linux/of.h | 1 + > 2 files changed, 28 insertions(+) > > v1->v2: > - Moved to using "cache-level" in the last level cache instead > of counting through all the nodes as suggested by Rob > > diff --git a/drivers/of/base.c b/drivers/of/base.c > index d4bea3c797d6..c1128a077aea 100644 > --- a/drivers/of/base.c > +++ b/drivers/of/base.c > @@ -25,6 +25,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -2268,6 +2269,32 @@ struct device_node *of_find_next_cache_node(const struct device_node *np) > } > > /** > + * of_find_last_cache_level - Find the level at which the last cache is > + * present for the given logical cpu > + * > + * @cpu: cpu number(logical index) for which the last cache level is needed > + * > + * Returns the the level at which the last cache is present. It is exactly > + * same as the total number of cache levels for the given logical cpu. > + */ > +int of_find_last_cache_level(unsigned int cpu) > +{ > + int cache_level = 0; > + struct device_node *prev = NULL, *np = of_cpu_device_node_get(cpu); > + > + while (np) { > + prev = np; > + of_node_put(np); > + np = of_find_next_cache_node(np); > + } > + > + if (prev) > + of_property_read_u32(prev, "cache-level", &cache_level); > + > + return cache_level; > +} > + > +/** > * of_graph_parse_endpoint() - parse common endpoint node properties > * @node: pointer to endpoint device_node > * @endpoint: pointer to the OF endpoint data structure > diff --git a/include/linux/of.h b/include/linux/of.h > index d72f01009297..21e6323de0f3 100644 > --- a/include/linux/of.h > +++ b/include/linux/of.h > @@ -280,6 +280,7 @@ extern struct device_node *of_get_child_by_name(const struct device_node *node, > > /* cache lookup */ > extern struct device_node *of_find_next_cache_node(const struct device_node *); > +extern int of_find_last_cache_level(unsigned int cpu); > extern struct device_node *of_find_node_with_property( > struct device_node *from, const char *prop_name); > > -- > 2.7.4 > > > . >