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From:   Robert Marko <robert.marko@sartura.hr>
Date:   Mon, 31 Jan 2022 14:00:25 +0100
Message-ID: <CA+HBbNE5nRmFAR44gYMW+Uqi_5e4s+4wBGoQTUbnhC0Pdkc6iw@mail.gmail.com>
Subject: Re: [PATCH v9 03/13] ARM: Add basic support for Airoha EN7523 SoC
To:     Felix Fietkau <nbd@nbd.name>
Cc:     Luka Perkov <luka.perkov@sartura.hr>,
        Russell King <linux@armlinux.org.uk>,
        Arnd Bergmann <arnd@arndb.de>, Olof Johansson <olof@lixom.net>,
        soc@kernel.org, Rob Herring <robh+dt@kernel.org>,
        linux-mediatek@lists.infradead.org,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        John Crispin <john@phrozen.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        devicetree <devicetree@vger.kernel.org>
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On Mon, Jan 31, 2022 at 1:57 PM Felix Fietkau <nbd@nbd.name> wrote:
>
>
> On 31.01.22 11:51, Luka Perkov wrote:
> > Hello Felix,
> >
> > On Sun, Jan 30, 2022 at 3:56 PM Felix Fietkau <nbd@nbd.name> wrote:
> >>
> >> From: John Crispin <john@phrozen.org>
> >>
> >> EN7523 is an armv8 based silicon used inside broadband access type devices
> >> such as xPON and xDSL. It shares various silicon blocks with MediaTek
> >> silicon such as the MT7622.
> >>
> >> Add basic support for Airoha EN7523, enough for booting to console.
> >>
> >> The UART is basically 8250-compatible, except for the clock selection.
> >> A clock-frequency value is synthesized to get this to run at 115200 bps.
> >>
> >> Signed-off-by: John Crispin <john@phrozen.org>
> >> Signed-off-by: Bert Vermeulen <bert@biot.com>
> >> Signed-off-by: Felix Fietkau <nbd@nbd.name>
> >> ---
> >> index 000000000000..ea23b5abb478
> >> --- /dev/null
> >> +++ b/arch/arm/mach-airoha/airoha.c
> >> @@ -0,0 +1,16 @@
> >> +// SPDX-License-Identifier: GPL-2.0-or-later
> >> +/*
> >> + * Device Tree support for Airoha SoCs
> >> + *
> >> + * Copyright (c) 2022 Felix Fietkau <nbd@nbd.name>
> >> + */
> >> +#include <asm/mach/arch.h>
> >> +
> >> +static const char * const airoha_board_dt_compat[] = {
> >> +       "airoha,en7523",
> >> +       NULL,
> >> +};
> >> +
> >> +DT_MACHINE_START(MEDIATEK_DT, "Airoha Cortex-A53 (Device Tree)")
> >
> > Since this is Cortex-A53 core is there a reason why this is not placed
> > within arm64 directory?
>  From what I can tell, it's a stripped-down core that only runs in
> 32-bit mode.

Hmm, this is new for me that you could do that to an ARMv8 (A53) core.
I know that you can run ARMv7 code but not that you can reduce it to
32 bit only.

Regards,
Robert
>
> - Felix


-- 
Robert Marko
Staff Embedded Linux Engineer
Sartura Ltd.
Lendavska ulica 16a
10000 Zagreb, Croatia
Email: robert.marko@sartura.hr
Web: www.sartura.hr