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From:   Leonard Crestez <leonard.crestez@nxp.com>
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        Anson Huang <anson.huang@nxp.com>, Jacky Bai <ping.bai@nxp.com>
Subject: Re: [PATCH] soc: imx: Get iMX8MQ revision for B0 from ATF
Thread-Topic: [PATCH] soc: imx: Get iMX8MQ revision for B0 from ATF
Thread-Index: AQHVAbePp28Sq24nH0ukEcxeJWhXpA==
Date:   Tue, 7 May 2019 10:24:10 +0000
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On 03.05.2019 16:53, Guido G=FCnther wrote:=0A=
> This is similar to what the BSP does and needed to e.g. determine=0A=
> necessary quirks for MIPI DSI.=0A=
> =0A=
> Signed-off-by: Guido G=FCnther <agx@sigxcpu.org>=0A=
> =0A=
>  From the list discussion and changelog it's not clear to me why a=0A=
> different method was chosen for the B1 silicon so I left that in place=0A=
> as is and only trigger on the B0 silicon I have here.=0A=
=0A=
Fetching revision without an ATF call was done for the sake of avoiding =0A=
depending on ATF as much as vendor tree does. I'm not sure avoiding ATF =0A=
dependencies is a good approach.=0A=
=0A=
The imx8mq reference manual claims that 0x3036006c is should be soc =0A=
revision but that incorrectly reports 0x00824010 meaning "A0" on all =0A=
chips. So some nasty hacks are done in ATF instead by poking at ROM and =0A=
OCOTP.=0A=
=0A=
There were multiple discussions also for GPCv2 and 8mm about how much to =
=0A=
rely on firmware. I personally think that duplicating ATF workarounds =0A=
just makes supporting imx8m harder in Linux. Don't we want firmware to =0A=
help us with silicon erratas?=0A=
=0A=
> +#define IMX8MQ_ATF_GET_SOC_INFO		0xc2000006=0A=
=0A=
Any reason not to use original FSL_SIP_GET_SOC_INFO constant name?=0A=
=0A=
Since ATF can fetch revision for B1 as well it makes no sense to keep =0A=
the old code if we switch to using a SIP call, just call ATF always.=0A=
=0A=
ATF upstream currently has 8mq support but no SIP call for GET_SOC_INFO, =
=0A=
that could be added easily.=0A=
=0A=
--=0A=
Regards,=0A=
Leonard=0A=