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From: swarren@wwwdotorg•org (Stephen Warren)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 6/6] ARM: tegra114: add CPU hotplug support
Date: Wed, 15 May 2013 17:11:41 -0600	[thread overview]
Message-ID: <5194162D.7010007@wwwdotorg.org> (raw)
In-Reply-To: <1368613644-11863-7-git-send-email-josephl@nvidia.com>

On 05/15/2013 04:27 AM, Joseph Lo wrote:
> The Tegra114 is a quad cores SoC. Each core can be hotplugged including
> CPU0. The hotplug sequence can be controlled by setting event trigger in
> flow controller. Then the flow controller will take care all the power
> sequence that include CPU up and down.

> diff --git a/arch/arm/mach-tegra/Makefile b/arch/arm/mach-tegra/Makefile

> +obj-$(CONFIG_ARCH_TEGRA_114_SOC)	+= sleep-tegra30.o

CONFIG_ARCH_TEGRA_3x_SOC also adds that to obj-y. Will including it
twice cause problems?

> diff --git a/arch/arm/mach-tegra/reset-handler.S b/arch/arm/mach-tegra/reset-handler.S

>   *	  CPU boot vector when restarting the a CPU following
>   *	  an LP2 transition. Also branched to by LP0 and LP1 resume after
>   *	  re-enabling sdram.
> + *
> + *	r6: SoC ID << 8

I meant to ask in patch 1: Perhaps the macro could do a >>8 so that code
can compare directly against the SoC IDs instead of having to compare
against shifted values.

> +	tegra_check_soc_id TEGRA114, TEGRA_APB_MISC_BASE, r6, r7
> +	beq	no_cpu0_chk

Does that need a THUMB(it ...) added? Same elsewhere.

> +	cmp	r6, #(TEGRA114 <<8)

Needs a space after <<.

> diff --git a/arch/arm/mach-tegra/sleep-tegra30.S b/arch/arm/mach-tegra/sleep-tegra30.S

> @@ -45,12 +46,17 @@ ENDPROC(tegra30_hotplug_shutdown)
>   * and powergates it -- flags (in R0) indicate the request type.
>   * Must never be called for CPU 0.

That comment is wrong now, I think.

>  	tst	r0, #TEGRA30_POWER_HOTPLUG_SHUTDOWN
> +	beq	flow_ctrl_setting_for_lp2
> +
> +	/* flow controller set up for hotplug */
> +	mov	r3, #FLOW_CTRL_WAITEVENT		@ For hotplug
> +	b	flow_ctrl_done
> +flow_ctrl_setting_for_lp2:
> +	/* flow controller set up for LP2 */
> +	cmp	r10, #(TEGRA30 << 8)
>  	moveq   r3, #FLOW_CTRL_WAIT_FOR_INTERRUPT	@ For LP2

Do you need e.g. "movne r3, #0" or similar here? Otherwise, I think r3
ends up not being initialized.

> -	movne	r3, #FLOW_CTRL_WAITEVENT		@ For hotplug
> +flow_ctrl_done:
> +	cmp	r10, #(TEGRA30 << 8)
>  	str	r3, [r2]

I wonder whether creating a separate tegra114_cpu_shutdown() wouldn't be
better, to avoid all the runtime conditional code.

  reply	other threads:[~2013-05-15 23:11 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-05-15 10:27 [PATCH 0/6] ARM: tegra114: add CPU hotplug support Joseph Lo
2013-05-15 10:27 ` [PATCH 1/6] ARM: tegra: add an assembly marco to check Tegra SoC ID Joseph Lo
2013-05-15 22:43   ` Stephen Warren
2013-05-16 10:09     ` Joseph Lo
2013-05-16 18:21       ` Stephen Warren
2013-05-15 10:27 ` [PATCH 2/6] ARM: tegra: skip SCU and PL310 code when CPU is not Cortex-A9 Joseph Lo
2013-05-15 22:48   ` Stephen Warren
2013-05-16 10:13     ` Joseph Lo
2013-05-15 10:27 ` [PATCH 3/6] ARM: tegra: make tegra_resume can work for Tegra114 Joseph Lo
2013-05-15 22:57   ` Stephen Warren
2013-05-16 10:35     ` Joseph Lo
2013-05-16 18:24       ` Stephen Warren
2013-05-15 10:27 ` [PATCH 4/6] ARM: tegra114: add power up sequence for warm boot CPU Joseph Lo
2013-05-15 10:27 ` [PATCH 5/6] clk: tegra114: implement wait_for_reset and disable_clock for tegra_cpu_car_ops Joseph Lo
2013-05-15 23:02   ` Stephen Warren
2013-05-16 19:17   ` Mike Turquette
2013-05-15 10:27 ` [PATCH 6/6] ARM: tegra114: add CPU hotplug support Joseph Lo
2013-05-15 23:11   ` Stephen Warren [this message]
2013-05-16 11:14     ` Joseph Lo
2013-05-16 18:26       ` Stephen Warren
2013-05-15 23:38 ` [PATCH 0/6] " Stephen Warren
2013-05-16  9:53   ` Joseph Lo
2013-05-16 18:19     ` Stephen Warren
2013-05-17 10:15       ` Joseph Lo
2013-05-17 10:27       ` Russell King - ARM Linux
2013-05-17 10:23     ` Russell King - ARM Linux

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