Re: [PATCH v3 5/6] xen/arm: zynqmp: implement zynqmp_eemi

From: Julien Grall <julien.grall@arm.com>
To: Stefano Stabellini <sstabellini@kernel.org>
Cc: edgar.iglesias@xilinx.com,
	Stefano Stabellini <stefanos@xilinx.com>, nd <nd@arm.com>,
	Stefano Stabellini <stefano.stabellini@xilinx.com>,
	xen-devel@lists.xen.org
Subject: Re: [PATCH v3 5/6] xen/arm: zynqmp: implement zynqmp_eemi
Date: Tue, 16 Oct 2018 14:44:55 +0100	[thread overview]
Message-ID: <e755f5d7-a5b9-b91c-b6e9-2c40fd080935@arm.com> (raw)
In-Reply-To: <alpine.DEB.2.10.1810161446200.5150@sstabellini-ThinkPad-X260>

Hi,

On 10/16/2018 07:48 AM, Stefano Stabellini wrote:
> On Mon, 15 Oct 2018, Julien Grall wrote:
>> (Resending the e-mail using a different smtp)
>>
>> On 15/10/2018 08:32, Julien Grall wrote:
>>> Hi,
>>>
>>> On 10/10/2018 11:49 PM, Stefano Stabellini wrote:
>>>> On Tue, 28 Aug 2018, Julien Grall wrote:
>>>>> Hi Stefano,
>>>>>
>>>>> On 11/08/18 01:01, Stefano Stabellini wrote:
>>>>>> From: "Edgar E. Iglesias" <edgar.iglesias@xilinx.com>
>>>>>>
>>>>>> From: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
>>>>>>
>>>>>> zynqmp_eemi uses the defined functions and structs to decide whether
>>>>>> to
>>>>>> make a call to the firmware, or to simply return a predefined value.
>>>>>>
>>>>>> Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
>>>>>> Signed-off-by: Stefano Stabellini <stefanos@xilinx.com>
>>>>>> ---e
>>>>>>     xen/arch/arm/platforms/xilinx-zynqmp-eemi.c | 143
>>>>>> +++++++++++++++++++++++++++-
>>>>>>     1 file changed, 142 insertions(+), 1 deletion(-)
>>>>>>
>>>>>> diff --git a/xen/arch/arm/platforms/xilinx-zynqmp-eemi.c
>>>>>> b/xen/arch/arm/platforms/xilinx-zynqmp-eemi.c
>>>>>> index 62cc15c..1dbdf04 100644
>>>>>> --- a/xen/arch/arm/platforms/xilinx-zynqmp-eemi.c
>>>>>> +++ b/xen/arch/arm/platforms/xilinx-zynqmp-eemi.c
>>>>>> @@ -808,7 +808,148 @@ static bool domain_has_mmio_access(struct domain
>>>>>> *d,
>>>>>>       bool zynqmp_eemi(struct cpu_user_regs *regs)
>>>>>>     {
>>>>>> -    return false;
>>>>>> +    struct arm_smccc_res res;
>>>>>> +    bool is_mmio_write = false;
>>>>>> +    uint32_t fid = get_user_reg(regs, 0);
>>>>>> +    uint32_t nodeid = get_user_reg(regs, 1);
>>>>>> +    unsigned int pm_fn = fid & 0xFFFF;
>>>>>
>>>>> Here you will receive all the function ID for the SIP subsystem. Can you
>>>>> confirm the EEMI can be accessed from both SMC32 and SMC64 convention?
>>>>
>>>> Yep
>>>
>>> Can you point me to the documentation? For instance, CALL_COUNT, UID and
>>> VERSION are only accessible via SMC32.
> 
> https://www.xilinx.com/support/documentation/user_guides/ug1200-eemi-api.pdf
> 
> I am checking if there is a newer version of it.

I am afraid I can't find the function ID in that documentation nor any 
mention of the SMC calling convention. I am surprised that EEMI would 
ignore tops bits of the ID given they convey different information (e.g 
fast/yielding call, 32/64-bit convention).

Looking at the branch you mentioned earlier on, zynqmp_pm_invoke_fn 
(drivers/firmware/xilinx/zynqmp.c) is definitely using the SMC64 calling 
convention as described in the documentation above the function.

Cheers,

-- 
Julien Grall

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