From: Grygorii Strashko <grygorii.strashko@ti.com>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
Saravana Kannan <saravanak@google.com>
Cc: Rob Herring <robh+dt@kernel.org>,
Frank Rowand <frowand.list@gmail.com>, <geert+renesas@glider.be>,
<gregkh@linuxfoundation.org>, <linux-omap@vger.kernel.org>,
<linux-pm@vger.kernel.org>, <peter.ujfalusi@ti.com>,
<rjw@rjwysocki.net>, <tomi.valkeinen@ti.com>, <tony@atomide.com>,
<ulf.hansson@linaro.org>, <kernel-team@android.com>,
<devicetree@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v1] of: platform: Batch fwnode parsing in the init_machine() path
Date: Fri, 2 Oct 2020 18:03:48 +0300 [thread overview]
Message-ID: <e0ef8816-11ea-3a1a-cac6-14b9f6c92bcf@ti.com> (raw)
In-Reply-To: <17bdc3f0-d816-151a-fef2-88cd38fc8621@ti.com>
On 02/10/2020 14:40, Grygorii Strashko wrote:
>
>
> On 02/10/2020 02:19, Laurent Pinchart wrote:
>> Hi Saravana,
>>
>> Thank you for the patch.
>>
>> On Thu, Oct 01, 2020 at 03:59:51PM -0700, Saravana Kannan wrote:
>>> When commit 93d2e4322aa7 ("of: platform: Batch fwnode parsing when
>>> adding all top level devices") optimized the fwnode parsing when all top
>>> level devices are added, it missed out optimizing this for platform
>>> where the top level devices are added through the init_machine() path.
>>>
>>> This commit does the optimization for all paths by simply moving the
>>> fw_devlink_pause/resume() inside of_platform_default_populate().
>>
>> Based on v5.9-rc5, before the patch:
>>
>> [ 0.652887] cpuidle: using governor menu
>> [ 12.349476] No ATAGs?
>>
>> After the patch:
>>
>> [ 0.650460] cpuidle: using governor menu
>> [ 12.262101] No ATAGs?
>>
>> :-(
>
> This is kinda expected :( because omap2 arch doesn't call of_platform_default_populate()
>
> Call path:
> board-generic.c
> DT_MACHINE_START()
> .init_machine = omap_generic_init,
>
> omap_generic_init()
> pdata_quirks_init(omap_dt_match_table);
> of_platform_populate(NULL, omap_dt_match_table,
> omap_auxdata_lookup, NULL);
>
> Other affected platforms
> arm: mach-ux500
> some mips
> some powerpc
>
> there are also case when a lot of devices placed under bus node, in such case
> of_platform_populate() calls from bus drivers will also suffer from this issue.
>
> I think one option could be to add some parameter to _populate() or introduce new api.
>
> By the way, is there option to disable this feature at all?
> Is there Kconfig option?
> Is there any reasons why such complex and time consuming code added to the kernel and not implemented on DTC level?
>
>
> Also, I've came with another diff, pls check.
>
> [ 0.000000] Booting Linux on physical CPU 0x0
> [ 0.000000] Linux version 5.9.0-rc6-01791-g9acba6b38757-dirty (grygorii@grygorii-XPS-13-9370) (arm-linux-gnueabihf-gcc (GNU Toolcha0
> [ 0.000000] CPU: ARMv7 Processor [412fc0f2] revision 2 (ARMv7), cr=10c5387d
> [ 0.000000] CPU: div instructions available: patching division code
> [ 0.000000] CPU: PIPT / VIPT nonaliasing data cache, PIPT instruction cache
> [ 0.000000] OF: fdt: Machine model: TI AM5718 IDK
> ...
> [ 0.053443] cpuidle: using governor ladder
> [ 0.053470] cpuidle: using governor menu
> [ 0.089304] No ATAGs?
> ...
> [ 3.092291] devtmpfs: mounted
> [ 3.095804] Freeing unused kernel memory: 1024K
> [ 3.100483] Run /sbin/init as init process
>
>
>
> ------ >< ---
> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> index 071f04da32c8..4521b26e7745 100644
> --- a/drivers/of/platform.c
> +++ b/drivers/of/platform.c
> @@ -514,6 +514,12 @@ static const struct of_device_id reserved_mem_matches[] = {
> {}
> };
>
> +static int __init of_platform_fw_devlink_pause(void)
> +{
> + fw_devlink_pause();
> +}
> +core_initcall(of_platform_fw_devlink_pause);
> +
> static int __init of_platform_default_populate_init(void)
> {
> struct device_node *node;
> @@ -538,9 +544,7 @@ static int __init of_platform_default_populate_init(void)
> }
>
> /* Populate everything else. */
> - fw_devlink_pause();
> of_platform_default_populate(NULL, NULL, NULL);
> - fw_devlink_resume();
>
> return 0;
> }
> @@ -548,6 +552,7 @@ arch_initcall_sync(of_platform_default_populate_init);
>
> static int __init of_platform_sync_state_init(void)
> {
> + fw_devlink_resume();
^ it seems has to be done earlier, like
+static int __init of_platform_fw_devlink_resume(void)
+{
+ fw_devlink_resume();
+ return 0;
+}
+device_initcall_sync(of_platform_fw_devlink_resume);
> device_links_supplier_sync_state_resume();
> return 0;
> }
>
>
>
--
Best regards,
grygorii
next prev parent reply other threads:[~2020-10-02 15:04 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200924055313.GC9471@atomide.com>
[not found] ` <fe0a4fa8-53fc-d316-261f-52f631f12469@ti.com>
[not found] ` <20200924060826.GE9471@atomide.com>
[not found] ` <20200924133049.GH3968@pendragon.ideasonboard.com>
[not found] ` <20200925115147.GM9471@atomide.com>
[not found] ` <20200925115817.GB3933@pendragon.ideasonboard.com>
[not found] ` <20200930052057.GP9471@atomide.com>
[not found] ` <d8d81891-7e22-81a2-19df-6e9a5f8679c4@ti.com>
[not found] ` <20201001075344.GU9471@atomide.com>
[not found] ` <20201001081748.GW9471@atomide.com>
[not found] ` <20201001082256.GA3722@pendragon.ideasonboard.com>
2020-10-01 12:56 ` Slow booting on x15 Grygorii Strashko
2020-10-01 13:11 ` Geert Uytterhoeven
2020-10-01 13:49 ` Grygorii Strashko
2020-10-01 18:24 ` Saravana Kannan
2020-10-01 19:43 ` Grygorii Strashko
2020-10-01 22:22 ` Saravana Kannan
2020-10-01 22:30 ` Saravana Kannan
2020-10-01 22:38 ` Laurent Pinchart
2020-10-01 22:44 ` Saravana Kannan
2020-10-01 22:59 ` [PATCH v1] of: platform: Batch fwnode parsing in the init_machine() path Saravana Kannan
2020-10-01 23:19 ` Laurent Pinchart
2020-10-02 11:40 ` Grygorii Strashko
2020-10-02 15:03 ` Grygorii Strashko [this message]
2020-10-02 17:48 ` Saravana Kannan
2020-10-02 18:11 ` Grygorii Strashko
2020-10-02 14:07 ` Rob Herring
2020-10-02 17:51 ` Saravana Kannan
2020-10-02 17:54 ` Laurent Pinchart
2020-10-02 17:58 ` Saravana Kannan
2020-10-02 18:27 ` Laurent Pinchart
2020-10-02 18:35 ` Grygorii Strashko
2020-10-02 19:56 ` Saravana Kannan
2020-10-03 0:13 ` Laurent Pinchart
2020-10-27 3:29 ` Saravana Kannan
2020-10-28 7:34 ` Tomi Valkeinen
2020-10-02 20:29 ` Rob Herring
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