linux-kernel - Re: [PATCHv2] arm: mach-omap2: prevent UART console idle on suspend while using "no_console

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Message-ID: <515ADE7C.1020303@amarulasolutions.com>
Date:	Tue, 02 Apr 2013 15:34:52 +0200
From:	Michael Trimarchi <michael@...rulasolutions.com>
To:	Sourav Poddar <sourav.poddar@...com>
CC:	tony@...mide.com, khilman@...aro.org, rmk+kernel@....linux.org.uk,
	gregkh@...uxfoundation.org, linux-serial@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-omap@...r.kernel.org,
	b-cousson@...com, Santosh Shilimkar <santosh.shilimkar@...com>,
	Felipe Balbi <balbi@...com>, Rajendra nayak <rnayak@...com>
Subject: Re: [PATCHv2] arm: mach-omap2: prevent UART console idle on suspend
 while using "no_console_suspend"

Hi

On 02/04/13 15:28, Sourav Poddar wrote:
> With dt boot, uart wakeup after suspend is non functional while using
> "no_console_suspend" in the bootargs. With "no_console_suspend" used, od->flags
> should be ORed with "OMAP_DEVICE_NO_IDLE_ON_SUSPEND", thereby not allowing the console
> to idle in the suspend path.
> 
> Tested on omap5430evm, omap4430sdp.
> 
> Cc: Santosh Shilimkar<santosh.shilimkar@...com>
> Cc: Felipe Balbi<balbi@...com>
> Cc: Rajendra nayak<rnayak@...com>
> Signed-off-by: Sourav Poddar <sourav.poddar@...com>
> ---
> v1->v2
> These patches were sent before as a series[1], but realised
> "core_initcall(omap_serial_early_init)" in serial.c get executed
> irrespective of dt or non dt boot and it will do most of the stuff
> for us.
> As suggested by Kevin Hilman in the previous version, this patch will
> also prevent creating dependency between omap_device
> (generic device-independent code) and a specific driver (UART).
> 
> [1]: http://lkml.org/lkml/2013/3/18/294
> 
>  arch/arm/mach-omap2/omap_device.c |    5 +++--
>  arch/arm/mach-omap2/omap_hwmod.h  |    5 +++++
>  arch/arm/mach-omap2/serial.c      |    4 +++-
>  3 files changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm/mach-omap2/omap_device.c b/arch/arm/mach-omap2/omap_device.c
> index 381be7a..89be64d 100644
> --- a/arch/arm/mach-omap2/omap_device.c
> +++ b/arch/arm/mach-omap2/omap_device.c
> @@ -170,8 +170,9 @@ static int omap_device_build_from_dt(struct platform_device *pdev)
>  			r->name = dev_name(&pdev->dev);
>  	}
>  
> -	if (of_get_property(node, "ti,no_idle_on_suspend", NULL))
> -		omap_device_disable_idle_on_suspend(pdev);
> +	if (oh->flags & HWMOD_DISABLE_IDLE_ON_SUSPEND ||
> +		of_get_property(node, "ti,no_idle_on_suspend", NULL))
> +			omap_device_disable_idle_on_suspend(pdev);
>  
>  	pdev->dev.pm_domain = &omap_device_pm_domain;
>  
> diff --git a/arch/arm/mach-omap2/omap_hwmod.h b/arch/arm/mach-omap2/omap_hwmod.h
> index d43d9b6..50e6145 100644
> --- a/arch/arm/mach-omap2/omap_hwmod.h
> +++ b/arch/arm/mach-omap2/omap_hwmod.h
> @@ -459,6 +459,10 @@ struct omap_hwmod_omap4_prcm {
>   *     correctly, or this is being abused to deal with some PM latency
>   *     issues -- but we're currently suffering from a shortage of
>   *     folks who are able to track these issues down properly.
> + * HWMOD_DISABLE_IDLE_ON_SUSPEND: don't idle this module on suspend. This is
> + *     needed for uart controller, which requires its clock not to be cut
> + *     during suspend while using "no_console_suspend" in bootargs with
> + *     device tree boot.
>   */
>  #define HWMOD_SWSUP_SIDLE			(1 << 0)
>  #define HWMOD_SWSUP_MSTANDBY			(1 << 1)
> @@ -471,6 +475,7 @@ struct omap_hwmod_omap4_prcm {
>  #define HWMOD_16BIT_REG				(1 << 8)
>  #define HWMOD_EXT_OPT_MAIN_CLK			(1 << 9)
>  #define HWMOD_BLOCK_WFI				(1 << 10)
> +#define HWMOD_DISABLE_IDLE_ON_SUSPEND		(1 << 12)

Just a comment more. Why 12 and not 11?

Michael

>  
>  /*
>   * omap_hwmod._int_flags definitions
> diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c
> index 8396b5b..adbafbd 100644
> --- a/arch/arm/mach-omap2/serial.c
> +++ b/arch/arm/mach-omap2/serial.c
> @@ -236,8 +236,10 @@ static int __init omap_serial_early_init(void)
>  					uart_name, uart->num);
>  			}
>  
> -			if (cmdline_find_option("no_console_suspend"))
> +			if (cmdline_find_option("no_console_suspend")) {
>  				no_console_suspend = true;
> +				oh->flags |= HWMOD_DISABLE_IDLE_ON_SUSPEND;
> +			}
>  
>  			/*
>  			 * omap-uart can be used for earlyprintk logs
> 

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