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From: Jeremy Linton <jeremy.linton@arm.com>
To: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
	Sudeep Holla <Sudeep.Holla@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>,
	Hanjun Guo <hanjun.guo@linaro.org>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Will Deacon <Will.Deacon@arm.com>,
	Catalin Marinas <Catalin.Marinas@arm.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Mark Rutland <Mark.Rutland@arm.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-riscv@lists.infradead.org, wangxiongfeng2@huawei.com,
	vkilari@codeaurora.org, Al Stone <ahs3@redhat.com>,
	Dietmar Eggemann <Dietmar.Eggemann@arm.com>,
	Morten Rasmussen <Morten.Rasmussen@arm.com>,
	palmer@sifive.com, Len Brown <lenb@kernel.org>,
	John Garry <john.garry@huawei.com>,
	austinwc@codeaurora.org, tnowicki@caviumnetworks.com,
	jhugo@qti.qualcomm.com, timur@qti.qualcomm.com,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>
Subject: Re: [PATCH v8 05/13] ACPI/PPTT: Add Processor Properties Topology Table parsing
Date: Fri, 27 Apr 2018 11:20:44 -0500	[thread overview]
Message-ID: <b750e86b-bc51-0440-b48d-0e8d3177fa8d@arm.com> (raw)
In-Reply-To: <CAJZ5v0jjPnyC0vm-Fb8y2hw1B9Uc2J5sZrtZYzt_ENT2Sini3A@mail.gmail.com>

Hi,

Thanks for taking a look at this.

On 04/27/2018 06:02 AM, Rafael J. Wysocki wrote:
> On Thu, Apr 26, 2018 at 1:31 AM, Jeremy Linton <jeremy.linton@arm.com> wrote:
>> ACPI 6.2 adds a new table, which describes how processing units
>> are related to each other in tree like fashion. Caches are
>> also sprinkled throughout the tree and describe the properties
>> of the caches in relation to other caches and processing units.
>>
>> Add the code to parse the cache hierarchy and report the total
>> number of levels of cache for a given core using
>> acpi_find_last_cache_level() as well as fill out the individual
>> cores cache information with cache_setup_acpi() once the
>> cpu_cacheinfo structure has been populated by the arch specific
>> code.
>>
>> An additional patch later in the set adds the ability to report
>> peers in the topology using find_acpi_cpu_topology()
>> to report a unique ID for each processing unit at a given level
>> in the tree. These unique id's can then be used to match related
>> processing units which exist as threads, within a given
>> package, etc.
>>
>> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
>> Acked-by: Sudeep Holla <sudeep.holla@arm.com>
>> ---
>>   drivers/acpi/pptt.c | 518 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>>   1 file changed, 518 insertions(+)
>>   create mode 100644 drivers/acpi/pptt.c
>>
>> diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c
>> new file mode 100644
>> index 000000000000..cced71ef851a
>> --- /dev/null
>> +++ b/drivers/acpi/pptt.c
>> @@ -0,0 +1,518 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * pptt.c - parsing of Processor Properties Topology Table
>> + *
>> + * Copyright (C) 2018, ARM
>> + *
>> + * This file implements parsing of Processor Properties Topology Table (PPTT)
>> + * which is optionally used to describe the processor and cache topology.
>> + * Due to the relative pointers used throughout the table, this doesn't
>> + * leverage the existing subtable parsing in the kernel.
>> + *
>> + * The PPTT structure is an inverted tree, with each node potentially
>> + * holding one or two inverted tree data structures describing
>> + * the caches available at that level. Each cache structure optionally
>> + * contains properties describing the cache at a given level which can be
>> + * used to override hardware probed values.
>> + */
>> +#define pr_fmt(fmt) "ACPI PPTT: " fmt
>> +
>> +#include <linux/acpi.h>
>> +#include <linux/cacheinfo.h>
>> +#include <acpi/processor.h>
>> +
>> +/**
>> + * fetch_pptt_subtable() - Find/Verify that the PPTT ref is a valid subtable
> 
> The parens above are at least redundant (if not harmful).  Everywhere
> else in a similar context too.

The kerneldoc ones? I guess i'm confused the kernel doc example in 
doc-guide/kernel-doc has

* function_name() - Brief description of function.


> 
> Also kerneldoc comments document function arguments too as a rule, so
> please do that here and wherever you use kerneldoc comments in the
> patchset.

Ok, sure.

> 
>> + *
>> + * Given the PPTT table, find and verify that the subtable entry
>> + * is located within the table
>> + *
>> + * Return: acpi_subtable_header* or NULL
>> + */
>> +static struct acpi_subtable_header *fetch_pptt_subtable(struct acpi_table_header *table_hdr,
>> +                                                       u32 pptt_ref)
>> +{
>> +       struct acpi_subtable_header *entry;
>> +
>> +       /* there isn't a subtable at reference 0 */
>> +       if (pptt_ref < sizeof(struct acpi_subtable_header))
>> +               return NULL;
>> +
>> +       if (pptt_ref + sizeof(struct acpi_subtable_header) > table_hdr->length)
>> +               return NULL;
>> +
>> +       entry = ACPI_ADD_PTR(struct acpi_subtable_header, table_hdr, pptt_ref);
>> +
>> +       if (entry->length == 0)
>> +               return NULL;
>> +
>> +       if (pptt_ref + entry->length > table_hdr->length)
>> +               return NULL;
>> +
>> +       return entry;
>> +}
> 
> Apart from the above I'm not entirely sure why you need the changes in
> patch [09/13] to go in a separate patch.  All of them are new code
> going into the file created by this patch, so why not to put them
> here?


Ok, I was doing that because Lorenzo asked for it, but he hasn't said 
much so I will collapse it back together. That makes me happy, as 
splitting chunks between patches is a pain anyway.

  reply	other threads:[~2018-04-27 16:20 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-25 23:31 [PATCH v8 00/13] Support PPTT for ARM64 Jeremy Linton
2018-04-25 23:31 ` [PATCH v8 01/13] drivers: base: cacheinfo: move cache_setup_of_node() Jeremy Linton
2018-04-25 23:31 ` [PATCH v8 02/13] drivers: base: cacheinfo: setup DT cache properties early Jeremy Linton
2018-04-25 23:31 ` [PATCH v8 03/13] cacheinfo: rename of_node to fw_token Jeremy Linton
2018-04-25 23:31 ` [PATCH v8 04/13] arm64/acpi: Create arch specific cpu to acpi id helper Jeremy Linton
2018-04-26 10:27   ` Sudeep Holla
2018-04-26 18:33     ` Jeremy Linton
2018-04-27 13:08       ` Sudeep Holla
2018-04-25 23:31 ` [PATCH v8 05/13] ACPI/PPTT: Add Processor Properties Topology Table parsing Jeremy Linton
2018-04-27 11:02   ` Rafael J. Wysocki
2018-04-27 16:20     ` Jeremy Linton [this message]
2018-04-30  7:59       ` Rafael J. Wysocki
2018-04-25 23:31 ` [PATCH v8 06/13] ACPI: Enable PPTT support on ARM64 Jeremy Linton
2018-04-25 23:31 ` [PATCH v8 07/13] drivers: base cacheinfo: Add support for ACPI based firmware tables Jeremy Linton
2018-04-26 11:05   ` Sudeep Holla
2018-04-26 18:57     ` Jeremy Linton
2018-04-27 12:49       ` Sudeep Holla
2018-04-25 23:31 ` [PATCH v8 08/13] arm64: " Jeremy Linton
2018-04-25 23:31 ` [PATCH v8 09/13] ACPI/PPTT: Add topology parsing code Jeremy Linton
2018-04-25 23:31 ` [PATCH v8 10/13] arm64: topology: rename cluster_id Jeremy Linton
2018-05-01 14:40   ` Sudeep Holla
2018-05-03 15:14   ` Morten Rasmussen
2018-04-25 23:31 ` [PATCH v8 11/13] arm64: topology: enable ACPI/PPTT based CPU topology Jeremy Linton
2018-05-01 14:46   ` Sudeep Holla
2018-05-02  8:24     ` Rafael J. Wysocki
2018-05-02 22:35       ` Jeremy Linton
2018-05-03  8:41         ` Rafael J. Wysocki
2018-05-03 15:15   ` Morten Rasmussen
2018-04-25 23:31 ` [PATCH v8 12/13] ACPI: Add PPTT to injectable table list Jeremy Linton
2018-04-25 23:31 ` [PATCH v8 13/13] arm64: topology: divorce MC scheduling domain from core_siblings Jeremy Linton
2018-05-01 14:33   ` Sudeep Holla
2018-05-02 11:49     ` Morten Rasmussen
2018-05-02 22:32       ` Jeremy Linton
2018-05-03 11:20         ` Morten Rasmussen
2018-05-02 22:34     ` Jeremy Linton
2018-05-03 15:12   ` Morten Rasmussen
2018-04-26  7:57 ` [PATCH v8 00/13] Support PPTT for ARM64 Ard Biesheuvel
2018-05-04  8:10 ` vkilari
2018-05-04 11:44   ` Sudeep Holla
2018-05-04 11:34 ` Xiongfeng Wang
2018-05-09 13:20 ` Tomasz Nowicki

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