From: Sudeep.KarkadaNagesha@arm•com (Sudeep KarkadaNagesha)
To: linux-arm-kernel@lists•infradead.org
Subject: [RFC PATCH 02/11] ARM: DT/kernel: define ARM specific arch_of_get_cpu_node
Date: Tue, 16 Jul 2013 10:03:21 +0100 [thread overview]
Message-ID: <51E50C59.50900@arm.com> (raw)
In-Reply-To: <51E44943.7000600@gmail.com>
On 15/07/13 20:10, Rob Herring wrote:
> On 07/15/2013 05:22 AM, Sudeep.KarkadaNagesha at arm.com wrote:
>> From: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm•com>
>>
>> CPU subsystem now provides architecture specific hook to retrieve the
>> of_node. Most of the cpu DT node parsing and initialisation is contained
>> in devtree.c. It's better to contain all CPU device node parsing there.
>>
>> arch_of_get_cpu_node is mainly used to assign cpu->of_node when CPUs get
>> registered. This patch overrides the defination of the same. It can also
>> act as the helper function in pre-SMP/early initialisation stages to
>> retrieve CPU device node pointers in logical ordering.
>>
>> This mainly helps to avoid replication of the code doing CPU node parsing
>> and physical(MPIDR) to logical mapping.
>>
>> Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm•com>
>
> [snip]
>
>> +struct device_node * __init arch_of_get_cpu_node(int cpu)
>> +{
>> + struct device_node *cpun, *cpus;
>> + const u32 *cell;
>> + u64 hwid;
>> + int ac;
>> +
>> + cpus = of_find_node_by_path("/cpus");
>> + if (WARN(!cpus, "Missing cpus node, bailing out\n"))
>> + return NULL;
>> +
>> + if (WARN_ON(of_property_read_u32(cpus, "#address-cells", &ac)))
>> + ac = of_n_addr_cells(cpus);
>> +
>> + for_each_child_of_node(cpus, cpun) {
>> + if (of_node_cmp(cpun->type, "cpu"))
>> + continue;
>> + cell = of_get_property(cpun, "reg", NULL);
>> + if (WARN(!cell, "%s: missing reg property\n", cpun->full_name))
>> + continue;
>> +
>> + hwid = of_read_number(cell, ac);
>> + if ((hwid & MPIDR_HWID_BITMASK) == cpu_logical_map(cpu))
>
> Most of this function is not ARM specific, so it would be nice if we
> could shrink the arch specific part down to just this match. A default
> match of reg == logical cpu number might be useful.
>
I completely agree, in fact that was my initial idea too.
But when I had a look at powerpc implementation of "of_get_cpu_node" in
arch/powerpc/kernel/prom.c, it looked like PPC is using some
compatibles(e.g. ibm,ppc-interrupt-server#s) which are not specified in
ePAPR. I am not sure is that's allowed or not, if allowed then we can't
have generic of_get_cpu_node with just arch specific hwid matching function.
Let me know how would you prefer me to proceed on this.
Regards,
Sudeep
next prev parent reply other threads:[~2013-07-16 9:03 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-15 10:22 [RFC PATCH 00/11] ARM: DT: update cpu device of_node Sudeep.KarkadaNagesha at arm.com
2013-07-15 10:22 ` [RFC PATCH 01/11] driver/core: cpu: initialize of_node in cpu's device struture Sudeep.KarkadaNagesha at arm.com
2013-07-16 6:27 ` Viresh Kumar
2013-07-15 10:22 ` [RFC PATCH 02/11] ARM: DT/kernel: define ARM specific arch_of_get_cpu_node Sudeep.KarkadaNagesha at arm.com
2013-07-15 19:10 ` Rob Herring
2013-07-16 6:29 ` Viresh Kumar
2013-07-16 9:03 ` Sudeep KarkadaNagesha [this message]
2013-07-17 14:16 ` Sudeep KarkadaNagesha
2013-07-15 10:22 ` [RFC PATCH 03/11] ARM: topology: remove hwid/MPIDR dependency from cpu_capacity Sudeep.KarkadaNagesha at arm.com
2013-07-15 10:22 ` [RFC PATCH 04/11] ARM: mvebu: remove device tree parsing for cpu nodes Sudeep.KarkadaNagesha at arm.com
2013-07-15 10:22 ` [RFC PATCH 05/11] drivers/bus: arm-cci: avoid parsing DT for cpu device nodes Sudeep.KarkadaNagesha at arm.com
2013-07-15 10:22 ` [RFC PATCH 06/11] cpufreq: imx6q-cpufreq: remove device tree parsing for cpu nodes Sudeep.KarkadaNagesha at arm.com
2013-07-16 1:22 ` Shawn Guo
2013-07-15 10:22 ` [RFC PATCH 07/11] cpufreq: cpufreq-cpu0: " Sudeep.KarkadaNagesha at arm.com
2013-07-16 1:26 ` Shawn Guo
2013-07-15 10:22 ` [RFC PATCH 08/11] cpufreq: highbank-cpufreq: " Sudeep.KarkadaNagesha at arm.com
2013-07-15 10:22 ` [RFC PATCH 09/11] cpufreq: spear-cpufreq: " Sudeep.KarkadaNagesha at arm.com
2013-07-15 10:22 ` [RFC PATCH 10/11] cpufreq: kirkwood-cpufreq: " Sudeep.KarkadaNagesha at arm.com
2013-07-15 10:22 ` [RFC PATCH 11/11] cpufreq: arm_big_little: " Sudeep.KarkadaNagesha at arm.com
2013-07-16 6:31 ` [RFC PATCH 00/11] ARM: DT: update cpu device of_node Viresh Kumar
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=51E50C59.50900@arm.com \
--to=sudeep.karkadanagesha@arm$(echo .)com \
--cc=linux-arm-kernel@lists$(echo .)infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox