linux-kernel - Re: [PATCH v3 4/4] ARM: OMAP2+: sleep43xx: Call secure suspend/resume handlers

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Message-ID: <a29d1e78-9736-ea93-8a53-4600f8f48cde@ti.com>
Date:   Tue, 31 Dec 2019 11:50:47 +0530
From:   Lokesh Vutla <lokeshvutla@...com>
To:     "Andrew F. Davis" <afd@...com>, Tony Lindgren <tony@...mide.com>
CC:     <linux-omap@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 4/4] ARM: OMAP2+: sleep43xx: Call secure suspend/resume
 handlers



On 31/12/19 12:20 AM, Andrew F. Davis wrote:
> During suspend CPU context may be lost in both non-secure and secure CPU
> states. The kernel can handle saving and restoring the non-secure context
> but must call into the secure side to allow it to save any context it may
> lose. Add these calls here.
> 
> Note that on systems with OP-TEE available the suspend call is issued to
> OP-TEE using the ARM SMCCC, but the resume call is always issued to the
> ROM. This is because on waking from suspend the ROM is restored as the
> secure monitor. It is this resume call that instructs the ROM to restore
> OP-TEE, all subsequent calls will be handled by OP-TEE and should use the
> ARM SMCCC.
> 
> Signed-off-by: Andrew F. Davis <afd@...com>
> Acked-by: Dave Gerlach <d-gerlach@...com>
> ---
>  arch/arm/mach-omap2/omap-secure.h |  3 +++
>  arch/arm/mach-omap2/pm33xx-core.c | 17 +++++++++++++++++
>  2 files changed, 20 insertions(+)
> 
> diff --git a/arch/arm/mach-omap2/omap-secure.h b/arch/arm/mach-omap2/omap-secure.h
> index 736e594365f4..ba8c486c0454 100644
> --- a/arch/arm/mach-omap2/omap-secure.h
> +++ b/arch/arm/mach-omap2/omap-secure.h
> @@ -53,6 +53,9 @@
>  #define OMAP4_PPA_L2_POR_INDEX		0x23
>  #define OMAP4_PPA_CPU_ACTRL_SMP_INDEX	0x25
>  
> +#define AM43xx_PPA_SVC_PM_SUSPEND	0x71
> +#define AM43xx_PPA_SVC_PM_RESUME	0x72
> +
>  /* Secure RX-51 PPA (Primary Protected Application) APIs */
>  #define RX51_PPA_HWRNG			29
>  #define RX51_PPA_L2_INVAL		40
> diff --git a/arch/arm/mach-omap2/pm33xx-core.c b/arch/arm/mach-omap2/pm33xx-core.c
> index f11442ed3eff..4a564f676ff9 100644
> --- a/arch/arm/mach-omap2/pm33xx-core.c
> +++ b/arch/arm/mach-omap2/pm33xx-core.c
> @@ -28,6 +28,7 @@
>  #include "prm33xx.h"
>  #include "soc.h"
>  #include "sram.h"
> +#include "omap-secure.h"
>  
>  static struct powerdomain *cefuse_pwrdm, *gfx_pwrdm, *per_pwrdm, *mpu_pwrdm;
>  static struct clockdomain *gfx_l4ls_clkdm;
> @@ -166,6 +167,16 @@ static int am43xx_suspend(unsigned int state, int (*fn)(unsigned long),
>  {
>  	int ret = 0;
>  
> +	/* Suspend secure side on HS devices */
> +	if (omap_type() != OMAP2_DEVICE_TYPE_GP) {
> +		if (optee_available)
> +			omap_smccc_smc(AM43xx_PPA_SVC_PM_SUSPEND, 0);
> +		else
> +			omap_secure_dispatcher(AM43xx_PPA_SVC_PM_SUSPEND,
> +					       FLAG_START_CRITICAL,
> +					       0, 0, 0, 0, 0);
> +	}
> +
>  	amx3_pre_suspend_common();
>  	scu_power_mode(scu_base, SCU_PM_POWEROFF);
>  	ret = cpu_suspend(args, fn);
> @@ -174,6 +185,12 @@ static int am43xx_suspend(unsigned int state, int (*fn)(unsigned long),
>  	if (!am43xx_check_off_mode_enable())
>  		amx3_post_suspend_common();
>  
> +	/* Resume secure side on HS devices */
> +	if (omap_type() != OMAP2_DEVICE_TYPE_GP)
> +		omap_secure_dispatcher(AM43xx_PPA_SVC_PM_RESUME,
> +				       FLAG_START_CRITICAL,
> +				       0, 0, 0, 0, 0);

Don't you need to check optee_available here?

Thanks and regards,
Lokesh

> +
>  	return ret;
>  }
>  
>