linux-kernel - Re: [PATCH v3 2/2] firmware: Keem Bay: Add support for Arm Trusted Firmware Service call

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Message-ID: <b29226d8-08ad-f708-73d7-1c4bb66e5767@xilinx.com>
Date:   Wed, 7 Oct 2020 15:58:40 +0200
From:   Michal Simek <michal.simek@...inx.com>
To:     "Zulkifli, Muhammad Husaini" <muhammad.husaini.zulkifli@...el.com>,
        Michal Simek <michal.simek@...inx.com>,
        "Hunter, Adrian" <adrian.hunter@...el.com>,
        "sudeep.holla@....com" <sudeep.holla@....com>,
        "ulf.hansson@...aro.org" <ulf.hansson@...aro.org>,
        "linux-mmc@...r.kernel.org" <linux-mmc@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Cc:     "Raja Subramanian, Lakshmi Bai" 
        <lakshmi.bai.raja.subramanian@...el.com>,
        "Wan Mohamad, Wan Ahmad Zainie" 
        <wan.ahmad.zainie.wan.mohamad@...el.com>,
        "arnd@...db.de" <arnd@...db.de>
Subject: Re: [PATCH v3 2/2] firmware: Keem Bay: Add support for Arm Trusted
 Firmware Service call

Hi,

On 07. 10. 20 15:52, Zulkifli, Muhammad Husaini wrote:
> Hi,
> 
>> -----Original Message-----
>> From: Michal Simek <michal.simek@...inx.com>
>> Sent: Wednesday, October 7, 2020 9:37 PM
>> To: Zulkifli, Muhammad Husaini <muhammad.husaini.zulkifli@...el.com>;
>> Michal Simek <michal.simek@...inx.com>; Hunter, Adrian
>> <adrian.hunter@...el.com>; sudeep.holla@....com; ulf.hansson@...aro.org;
>> linux-mmc@...r.kernel.org; linux-arm-kernel@...ts.infradead.org; linux-
>> kernel@...r.kernel.org
>> Cc: Raja Subramanian, Lakshmi Bai <lakshmi.bai.raja.subramanian@...el.com>;
>> Wan Mohamad, Wan Ahmad Zainie
>> <wan.ahmad.zainie.wan.mohamad@...el.com>; arnd@...db.de
>> Subject: Re: [PATCH v3 2/2] firmware: Keem Bay: Add support for Arm Trusted
>> Firmware Service call
>>
>> Hi,
>>
>> On 07. 10. 20 15:21, Zulkifli, Muhammad Husaini wrote:
>>> Hi Michal,
>>>
>>> Thanks for the feedback. I replied inline
>>>
>>>> -----Original Message-----
>>>> From: Michal Simek <michal.simek@...inx.com>
>>>> Sent: Wednesday, October 7, 2020 4:20 PM
>>>> To: Zulkifli, Muhammad Husaini <muhammad.husaini.zulkifli@...el.com>;
>>>> Hunter, Adrian <adrian.hunter@...el.com>; michal.simek@...inx.com;
>>>> sudeep.holla@....com; ulf.hansson@...aro.org;
>>>> linux-mmc@...r.kernel.org; linux-arm-kernel@...ts.infradead.org;
>>>> linux-kernel@...r.kernel.org
>>>> Cc: Raja Subramanian, Lakshmi Bai
>>>> <lakshmi.bai.raja.subramanian@...el.com>;
>>>> Wan Mohamad, Wan Ahmad Zainie
>>>> <wan.ahmad.zainie.wan.mohamad@...el.com>; arnd@...db.de
>>>> Subject: Re: [PATCH v3 2/2] firmware: Keem Bay: Add support for Arm
>>>> Trusted Firmware Service call
>>>>
>>>> Hi,
>>>>
>>>> 1. Keem Bay: in subject is wrong. Tools are working with it and you
>>>> should just use keembay: instead.
>>> Are you saying like this ?
>>> Keem Bay: Add support for Arm Trusted Firmware Service call
>>
>> like this:
>> firmware: keembay: Add support for Arm Trusted Firmware Service call
>>
>>>
>>>>
>>>> 2. This should come first before actual change to keep the tree bisectable.
>>> Noted. Done the changes
>>>>
>>>> On 06. 10. 20 17:55, muhammad.husaini.zulkifli@...el.com wrote:
>>>>> From: Muhammad Husaini Zulkifli
>>>>> <muhammad.husaini.zulkifli@...el.com>
>>>>>
>>>>> Add header file to handle API function for device driver to
>>>>> communicate with Arm Trusted Firmware.
>>>>>
>>>>> Signed-off-by: Muhammad Husaini Zulkifli
>>>>> <muhammad.husaini.zulkifli@...el.com>
>>>>> ---
>>>>>  .../linux/firmware/intel/keembay_firmware.h   | 46 +++++++++++++++++++
>>>>>  1 file changed, 46 insertions(+)
>>>>>  create mode 100644 include/linux/firmware/intel/keembay_firmware.h
>>>>>
>>>>> diff --git a/include/linux/firmware/intel/keembay_firmware.h
>>>>> b/include/linux/firmware/intel/keembay_firmware.h
>>>>> new file mode 100644
>>>>> index 000000000000..9adb8c87b788
>>>>> --- /dev/null
>>>>> +++ b/include/linux/firmware/intel/keembay_firmware.h
>>>>> @@ -0,0 +1,46 @@
>>>>> +/* SPDX-License-Identifier: GPL-2.0 */
>>>>> +/*
>>>>> + *  Intel Keembay SOC Firmware API Layer
>>>>> + *
>>>>> + *  Copyright (C) 2020-2021, Intel Corporation
>>>>> + *
>>>>> + *  Muhammad Husaini Zulkifli <Muhammad.Husaini.Zulkifli@...el.com>
>>>>> + */
>>>>> +
>>>>> +#ifndef __FIRMWARE_KEEMBAY_SMC_H__
>>>>> +#define __FIRMWARE_KEEMBAY_SMC_H__
>>>>> +
>>>>> +#include <linux/arm-smccc.h>
>>>>> +
>>>>> +/**
>>>>
>>>> This is not a kernel doc comment. Just use /*
>>>>
>>>>> + * This file defines API function that can be called by device
>>>>> + driver in order to
>>>>> + * communicate with Arm Trusted Firmware.
>>>>> + */
>>>>> +
>>>>> +/* Setting for Keem Bay IO Pad Line Voltage Selection */
>>>>> +#define KEEMBAY_SET_SD_VOLTAGE_FUNC_ID	0x8200ff26
>>>>
>>>> Sudeep: Don't we have any macros for composing these IDs?
>>>> nit: IMHO composing these IDs from macros would make more sense to me.
>>>>
>>>>
>>>>> +#define KEEMBAY_SET_1V8_VOLT		0x01
>>>>
>>>> 0x01 is just 1
>>> Noted. Done the changes
>>>>
>>>>> +#define KEEMBAY_SET_3V3_VOLT		0x00
>>>>
>>>> 0x00 is just 0
>>> Noted. Done the changes
>>>>
>>>>> +
>>>>> +#if IS_ENABLED(CONFIG_HAVE_ARM_SMCCC_DISCOVERY)
>>>>> +static int do_fw_invoke(u64 func_id, u64 arg0, u64 arg1) {
>>>>> +	struct arm_smccc_res res;
>>>>> +
>>>>> +	arm_smccc_1_1_invoke(func_id, arg0, arg1, &res);
>>>>> +
>>>>> +	return res.a0;
>>>>
>>>> I am not big fan of this error propagation in case of failure.
>>>>
>>>> If smc fails you get via res.a0 SMCCC_RET_NOT_SUPPORTED which is
>>>> defined as
>>>> -1 which is based on errno-base.h defined as EPERM.
>>>>
>>>> That driver which Sudeep pointed you to is using EINVAL instead.
>>>>
>>>> It means I would add a code to check it.
>>>
>>> Yeah I changed to below line of codes. Is this Ok? Tested working.
>>> int keembay_sd_voltage_selection(int volt)
>>
>> static inline here shouldn't hurt.
> due to func() prototype " int keembay_sd_voltage_selection(int volt);" to solve warning issues by robot , I cannot set static inline here. 
> Will observed below error:
> 
> error: static declaration of ‘keembay_sd_voltage_selection’ follows non-static declaration
>  static inline int keembay_sd_voltage_selection(int volt).

Will take a look at when you send new version.

Thanks,
Michal