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From: Daniel Palmer <daniel@0x0f.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: "Bert Vermeulen" <bert@biot.com>,
	"Russell King" <linux@armlinux.org.uk>,
	"Linus Walleij" <linus.walleij@linaro.org>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Geert Uytterhoeven" <geert+renesas@glider.be>,
	"Anshuman Khandual" <anshuman.khandual@arm.com>,
	"Marc Zyngier" <maz@kernel.org>,
	"Mark Rutland" <mark.rutland@arm.com>,
	"John Crispin" <john@phrozen.org>,
	"Ard Biesheuvel" <ardb@kernel.org>,
	"YiFei Zhu" <yifeifz2@illinois.edu>,
	"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
	"Mike Rapoport" <rppt@kernel.org>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
	"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
	DTML <devicetree@vger.kernel.org>
Subject: Re: [PATCH v2 4/5] ARM: Add basic support for Airoha EN7523 SoC
Date: Tue, 7 Sep 2021 23:32:20 +0900	[thread overview]
Message-ID: <CAFr9PX=Oi-HJYUFBfJn4pHUSk=drf7otyx473hvq1UC5_gaTHQ@mail.gmail.com> (raw)
In-Reply-To: <CAK8P3a0y0PhmOdMPnx10zG6s6RfiuC9Ju9s5SMnOk8oZ+cAFMw@mail.gmail.com>

Hi Arnd,

On Tue, 7 Sept 2021 at 23:12, Arnd Bergmann <arnd@arndb.de> wrote:

> > I think the broken memory controller is still there so somehow I'd
> > need to get the heavy barrier to work in arm64. I haven't yet worked
> > out if that's even possible.
>I think I missed that part of the discussion, or I forgot about it already.
>What is the issue you are referring to here?

Sorry. I should have put a bit more context. This is for the SSD268G
not the original target of this series. But a similar situation.
The SSD268G (according to the decompiled device tree) is the same
hardware as the MSTAR_V7 chips but with a Cortex A53 instead of the
Cortex A7.
So it probably has the same memory controller as the MSTAR_V7 stuff
and that memory controller is not coherent so it needs the kernel to
make sure memory requests are flushed out to memory before DMA
happens[0]. For arm I fixed that with the heavy mb callback. With
arm64 I have no idea how to fix that.

I'm interested to see how this Airoha EN7523 series goes as if/when I
push anything for the SSD268G it'll probably only be for a 32bit
kernel.

0 - https://elixir.bootlin.com/linux/latest/source/arch/arm/mach-mstar/mstarv7.c#L61

WARNING: multiple messages have this Message-ID (diff)
From: Daniel Palmer <daniel@0x0f.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: "Bert Vermeulen" <bert@biot.com>,
	"Russell King" <linux@armlinux.org.uk>,
	"Linus Walleij" <linus.walleij@linaro.org>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Geert Uytterhoeven" <geert+renesas@glider.be>,
	"Anshuman Khandual" <anshuman.khandual@arm.com>,
	"Marc Zyngier" <maz@kernel.org>,
	"Mark Rutland" <mark.rutland@arm.com>,
	"John Crispin" <john@phrozen.org>,
	"Ard Biesheuvel" <ardb@kernel.org>,
	"YiFei Zhu" <yifeifz2@illinois.edu>,
	"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
	"Mike Rapoport" <rppt@kernel.org>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
	"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
	DTML <devicetree@vger.kernel.org>
Subject: Re: [PATCH v2 4/5] ARM: Add basic support for Airoha EN7523 SoC
Date: Tue, 7 Sep 2021 23:32:20 +0900	[thread overview]
Message-ID: <CAFr9PX=Oi-HJYUFBfJn4pHUSk=drf7otyx473hvq1UC5_gaTHQ@mail.gmail.com> (raw)
In-Reply-To: <CAK8P3a0y0PhmOdMPnx10zG6s6RfiuC9Ju9s5SMnOk8oZ+cAFMw@mail.gmail.com>

Hi Arnd,

On Tue, 7 Sept 2021 at 23:12, Arnd Bergmann <arnd@arndb.de> wrote:

> > I think the broken memory controller is still there so somehow I'd
> > need to get the heavy barrier to work in arm64. I haven't yet worked
> > out if that's even possible.
>I think I missed that part of the discussion, or I forgot about it already.
>What is the issue you are referring to here?

Sorry. I should have put a bit more context. This is for the SSD268G
not the original target of this series. But a similar situation.
The SSD268G (according to the decompiled device tree) is the same
hardware as the MSTAR_V7 chips but with a Cortex A53 instead of the
Cortex A7.
So it probably has the same memory controller as the MSTAR_V7 stuff
and that memory controller is not coherent so it needs the kernel to
make sure memory requests are flushed out to memory before DMA
happens[0]. For arm I fixed that with the heavy mb callback. With
arm64 I have no idea how to fix that.

I'm interested to see how this Airoha EN7523 series goes as if/when I
push anything for the SSD268G it'll probably only be for a 32bit
kernel.

0 - https://elixir.bootlin.com/linux/latest/source/arch/arm/mach-mstar/mstarv7.c#L61

_______________________________________________
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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2021-09-07 14:29 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-07 10:27 [PATCH v2 0/5] Add support for Airoha EN7523 SoC Bert Vermeulen
2021-09-07 10:27 ` Bert Vermeulen
2021-09-07 10:27 ` [PATCH v2 1/5] dt-bindings: Add vendor prefix for Airoha Bert Vermeulen
2021-09-07 10:27   ` Bert Vermeulen
2021-09-07 11:13   ` Krzysztof Kozlowski
2021-09-07 11:13     ` Krzysztof Kozlowski
2021-09-07 10:27 ` [PATCH v2 2/5] dt-bindings: arm: airoha: Add binding for EN7523 SoC and EVB Bert Vermeulen
2021-09-07 10:27   ` Bert Vermeulen
2021-09-07 10:27 ` [PATCH v2 3/5] ARM: dts: Add basic support for Airoha EN7523 Bert Vermeulen
2021-09-07 10:27   ` Bert Vermeulen
2021-09-07 10:27 ` [PATCH v2 4/5] ARM: Add basic support for Airoha EN7523 SoC Bert Vermeulen
2021-09-07 10:27   ` Bert Vermeulen
2021-09-07 10:48   ` Daniel Palmer
2021-09-07 10:48     ` Daniel Palmer
2021-09-07 11:51     ` Arnd Bergmann
2021-09-07 11:51       ` Arnd Bergmann
2021-09-07 12:27       ` Daniel Palmer
2021-09-07 12:27         ` Daniel Palmer
2021-09-07 14:11         ` Arnd Bergmann
2021-09-07 14:11           ` Arnd Bergmann
2021-09-07 14:32           ` Daniel Palmer [this message]
2021-09-07 14:32             ` Daniel Palmer
2021-09-07 15:22             ` Arnd Bergmann
2021-09-07 15:22               ` Arnd Bergmann
2021-09-07 10:27 ` [PATCH v2 5/5] ARM: multi_v7_defconfig: Add " Bert Vermeulen
2021-09-07 10:27   ` Bert Vermeulen
2021-09-07 10:39   ` Dmitry Osipenko
2021-09-07 10:39     ` Dmitry Osipenko
2021-09-07 10:41     ` Bert Vermeulen
2021-09-07 10:41       ` Bert Vermeulen
2021-09-07 11:03       ` Dmitry Osipenko
2021-09-07 11:03         ` Dmitry Osipenko

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