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

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Date:   Wed, 7 Oct 2020 13:29:46 +0000
From:   "Zulkifli, Muhammad Husaini" <muhammad.husaini.zulkifli@...el.com>
To:     Sudeep Holla <sudeep.holla@....com>,
        Michal Simek <michal.simek@...inx.com>
CC:     "Hunter, Adrian" <adrian.hunter@...el.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>,
        "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 Sudeep,

Thanks for the feedback. I replied inline

>-----Original Message-----
>From: Sudeep Holla <sudeep.holla@....com>
>Sent: Wednesday, October 7, 2020 6:11 PM
>To: Michal Simek <michal.simek@...inx.com>
>Cc: Zulkifli, Muhammad Husaini <muhammad.husaini.zulkifli@...el.com>;
>Hunter, Adrian <adrian.hunter@...el.com>; Sudeep Holla
><sudeep.holla@....com>; ulf.hansson@...aro.org; linux-
>mmc@...r.kernel.org; linux-arm-kernel@...ts.infradead.org; linux-
>kernel@...r.kernel.org; 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
>
>On Wed, Oct 07, 2020 at 10:20:21AM +0200, Michal Simek wrote:
>> Hi,
>>
>> 1. Keem Bay: in subject is wrong. Tools are working with it and you
>> should just use keembay: instead.
>>
>> 2. This should come first before actual change to keep the tree bisectable.
>>
>> 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.
>>
>
>Yes we do. Refer include/linux/arm-smccc.h I expect something like below,
>which also indicated you are using wrong OWNER space. You can't be 0 which is
>reserved for CPU ARCH. You need to be SIP(0x2)
>
>#define ARM_SMCCC_SIP_KEEMBAY_SET_SD_VOLTAGE          \
>        ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,       \
>                           ARM_SMCCC_SMC_32,          \
>                           ARM_SMCCC_OWNER_SIP,       \
>                           0xFF26)
>
>
>--

Testing with below func and definition. It is working .
#define ARM_SMCCC_SIP_KEEMBAY_SET_SD_VOLTAGE          \
        ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,       \
                           ARM_SMCCC_SMC_32,          \
                           ARM_SMCCC_OWNER_SIP,       \
                           0xFF26)

int keembay_sd_voltage_selection(int volt)
{
	struct arm_smccc_res res;
	
	arm_smccc_1_1_invoke(ARM_SMCCC_SIP_KEEMBAY_SET_SD_VOLTAGE, volt, &res);
	if ((int)res.a0 < 0)
		return -EINVAL;

	return 0;
}
>Regards,
>Sudeep