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

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Date:   Thu, 2 Jan 2020 10:32:19 +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 7:47 PM, Andrew F. Davis wrote:
> On 12/31/19 1:20 AM, Lokesh Vutla wrote:
>>
>>
>> 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?
>>
> 
> 
> I address this in the second paragraph of the commit message. I can add
> a comment in code also if you think anyone will find it confusing.

Yeah, a comment would help.

Thanks and regards,
Lokesh

> 
> Andrew
> 
> 
>> Thanks and regards,
>> Lokesh
>>
>>> +
>>>  	return ret;
>>>  }
>>>  
>>>