Subject: Re: [PATCH 3/3] soc: xilinx: zynqmp: Add firmware interface
To: Arnd Bergmann <arnd@arndb.de>, Michal Simek <michal.simek@xilinx.com>
CC: Linux ARM <linux-arm-kernel@lists.infradead.org>,
        =?UTF-8?Q?S=c3=b6ren_Brinkmann?= <soren.brinkmann@xilinx.com>,
        Lucas Stach <l.stach@pengutronix.de>, Michal Simek <monstr@monstr.eu>,
        yangbo lu <yangbo.lu@nxp.com>,
        =?UTF-8?Q?Andreas_F=c3=a4rber?= <afaerber@suse.de>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Alexandre Belloni <alexandre.belloni@free-electrons.com>,
        Baoyou Xie <baoyou.xie@linaro.org>, Shawn Guo <shawnguo@kernel.org>,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        Nicolas Ferre <nicolas.ferre@microchip.com>,
        Simon Horman <horms+renesas@verge.net.au>
References: <cover.1501854302.git.michal.simek@xilinx.com>
 <98038734d73c604dee6ac0d34740d5bc2034e87d.1501854302.git.michal.simek@xilinx.com>
 <CAK8P3a1UhKAhYx2fCoWGm7HMka+8XrzFCxEphYNdyNS7yYR8cA@mail.gmail.com>
 <247a5660-6c53-ccc3-7b9f-bfd2a11f6f54@xilinx.com>
 <CAK8P3a3TsnYRWnurAduChLVc5q41vax_S0mpK5sQPUo5reM5bw@mail.gmail.com>
 <d55c3064-3db8-dad9-ac0a-8adad53465ff@xilinx.com>
 <3809b6a0-1cb9-37af-a524-8bc1986268ec@xilinx.com>
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From: Michal Simek <michal.simek@xilinx.com>
Message-ID: <5a53e449-b269-89da-9b69-e560132502fc@xilinx.com>
Date: Thu, 17 Aug 2017 12:48:08 +0200
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On 16.8.2017 17:05, Arnd Bergmann wrote:
> On Wed, Aug 16, 2017 at 4:34 PM, Michal Simek <michal.simek@xilinx.com> wrote:
>> On 16.8.2017 16:00, Michal Simek wrote:
>>> On 16.8.2017 14:41, Arnd Bergmann wrote:
>>>
>>
>> What do you think?
>>                 ret_payload[0] = lower_32_bits(le64_to_cpu(res.a0));
>>                 ret_payload[1] = upper_32_bits(le64_to_cpu(res.a0));
>>                 ret_payload[2] = lower_32_bits(le64_to_cpu(res.a1));
>>                 ret_payload[3] = upper_32_bits(le64_to_cpu(res.a1));
>>                 ret_payload[4] = lower_32_bits(le64_to_cpu(res.a2));
>>
>> There should be probably also change in invoke_pm_fn to do conversion
>> from cpu to le64.
>>
>> int invoke_pm_fn(u32 pm_api_id, u32 arg0, u32 arg1, u32 arg2, u32 arg3,
>>                  u32 *ret_payload)
>> {
>>         /*
>>          * Added SIP service call Function Identifier
>>          * Make sure to stay in x0 register
>>          */
>>         u64 smc_arg[4];
>>
>>         smc_arg[0] = cpu_to_le64(PM_SIP_SVC | pm_api_id);
>>         smc_arg[1] = cpu_to_le64(((u64)arg1 << 32) | arg0);
>>         smc_arg[2] = cpu_to_le64(((u64)arg3 << 32) | arg2);
>>
>>         return do_fw_call(smc_arg[0], smc_arg[1], smc_arg[2], ret_payload);
>> }
>>
>> This is not tested on BE just on LE.
> 
> Looks good, just make sure you also check with sparse (make C=1)
> to ensure you have the right __le64/__le32 types everywhere.

Are you aware about any doc where it is written that data should be
passed as little endian?

I was playing with it a little bit and this means that these 2(3 with
hvc) needs to be changed.

asmlinkage void __arm_smccc_smc(__le64 a0, __le64 a1, __le64 a2,
 __le64 a3,__le64 a4, __le64 a5, __le64 a6, __le64 a7,
struct arm_smccc_res *res, struct arm_smccc_quirk *quirk);

 struct arm_smccc_res {
-       unsigned long a0;
-       unsigned long a1;
-       unsigned long a2;
-       unsigned long a3;
+       __le64 a0;
+       __le64 a1;
+       __le64 a2;
+       __le64 a3;
 };

Thanks,
Michal